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The Soviet Union had planned to

Descripción: Original Title: The Soviet Union Had Planned to "Dig Through the Earth", Why Did It Stop Digging to 12262 Meters? What's the reason? In fact, competition seems to be a discordant factor, but in fact it is a reliable link that unites all the components of society. -Duno After the end of World War II, two superpowers appeared on the earth. One is the United States with capitalism as its core, and the other is the Soviet Union with communism as its core. In order to compete for hegemony in the world, the two countries began the famous "Cold War between the United States and the Soviet Union" in order to avoid a large-scale war. During this period, the two countries competed in economy, military, science and technology and other aspects. Under the promotion of the Cold War, the footsteps of human beings have moved into space. In addition, the level of science and technology in both countries is "rising" in various aspects, and even some shocking ideas become normal at this time. As long as it can be realized in theory, it will support the scientific research team to do research with strong national strength. At this time, the Soviet Union proposed a crazy experiment, intending to "dig through the earth". But the experiment stopped after a while. Why did the Soviet Union stop digging 12262 rice? What's the reason? After the end of the Second World War, the European powers were badly weakened. It once stood in the world's first-class powers, such as Britain, France and Germany, mining drill bit , which were surpassed by the United States and the Soviet Union and became second-class powers. But because of the huge differences in social system and ideology between the capitalist camp represented by the United States and the socialist camp represented by the Soviet Union, it is doomed that the two superpowers can not live in peace. Both countries believe that the social system they represent can lead mankind to a stronger position. After the British Prime Minister's "Iron Curtain Speech", the Cold War between the United States and the Soviet Union officially began, and a silent war lasted for decades. Expand the full text This offshoot of what the Soviets called the "Earth Telescope Project" was to reach the junction between the crust and the mantle before the United States. In 1970, the project was officially launched, and the Soviet Union mobilized a large number of scientists and workers to the Kola Peninsula. Those involved in digging the ground can get rich remuneration, enough to cover the wages of ordinary workers for several years, and each person can also get a house in Moscow. Stimulated by a large number of rewards, all the people involved in the project are energetic and the progress is very fast. As for the reason for stopping the project, the official announcement was that the scientific research funds were insufficient and could not continue to excavate. But how could the Soviet Union, which was at the height of its power at that time, be short of money? This made many people skeptical about the reasons for the official announcement. According to some staff, it was because of some supernatural phenomena during the excavation. Some people say that the Soviet Union's cave excavation accidentally opened the gates of hell, and demons appeared, so for the sake of people's safety, it was forced to stop all excavation. More than 10000 meters is indeed a long distance for human beings, but the radius of the huge earth is only 6371000 meters. So this plan to dig through the earth is just a gimmick, for those folk legends of demons, just an exaggeration of some phenomena. Even if the plan was terminated, the fact that the plan could be started and the drilling depth of 12000 meters was completed in that era also proved that the economic strength and scientific development of the Soviet Union were not simple. Such a plan, at that time, was a fantasy for all countries in the world except the United States. Return to Sohu to see more Responsible Editor: (function() { function getBrandHtml() { var brands = ,dhd drill bit, html = ''; for(var i = 0; i < brands.length; i++) { var brand = brands; if(brands.length i+1) { html+= '

Fecha de Publicación: 26-08-22

Design and Construction Organization Plan of Lightning Protection Engineering (I) _ Grounding

Descripción: Original Title: Lightning Protection Engineering Design and Construction Organization Plan (I) The lightning protection project needs to be implemented in an organized and step-by-step manner to ensure the quality and duration of the project. Today, Junhe Electronics takes a project as an example to share with you the template of lightning protection engineering design and construction organization scheme for reference only, as follows: I. Lightning protection design scheme 1. Project overview The project is located in XX Town, XX County, XX Province, which is surrounded by mountains on three sides. The project is located in the south of the XX fault zone. There are few soil layers in the project yard, no vegetation, mostly rocky mountains, and the soil resistivity is high. The available land area around the building is small, there is no vegetation soil layer, and it is mainly rock. The measured soil layer is 1420 Ω · m (the surface layer is backfill soil), and the grounding coefficient varies with the season. The measured soil resistivity of highly weathered dolomite in L201 and L202 buildings is 20000 ohm · m. 2. Analysis of design scheme There are many grounding methods for lightning protection, such as (1. Soil replacement method, 2. Artificial soil treatment method (chemical treatment of soil), 3. Deep buried grounding electrode method, 4. Multi-branch external grounding device method, 5. Grounding module grounding method, 6. Sewage introduction method, 7. Deep well grounding method). There are two grounding methods suitable for L201 and L202; Deep well grounding method and grounding module grounding method. Disadvantages of grounding method of grounding module: Due to the shallow soil layer of the project site, the geographical environment changes significantly in four seasons, and the rainfall is not balanced, which objectively causes the instability of soil temperature, humidity and water retention, and will affect the stability of the resistance of the whole ground network. It destroys the geological structure, occupies a large area, and the land used becomes dead and can not be reused. The service life of the module is short, the material composition is complex, ranging from several hundred yuan to several thousand yuan, and the module itself is fragile, which will affect the instability of the resistance value. The distance between the grounding grid of the lightning tower and the grounding grid of the building foundation is too close, which may lead to the formation of ground potential counterattack, resulting in serious consequences such as equipment damage. Module grounding needs to change the soil, but it is difficult for us to get the soil, and it also depends on what kind of soil (sandy soil, loess, black soil) will affect the resistance. The modules are connected by flat steel, which is easy to corrode and also affects the resistance. The extensive use of common resistance reducing agents has an impact on groundwater and soil quality, which is related to personal health and safety! In terms of price comparison, if better materials are used and products meet the requirements of national standards, the price difference between deep well grounding and deep well grounding is not very large. Advantages of deep well grounding method: The deep well grounding mode eliminates the influence of temperature difference in four seasons and ensures the stability of grounding grid resistance. It occupies a small area and will not affect the land use. The use of long-acting physical resistance reducing agent, green environmental protection, pollution-free, long life, in line with the standards of the national testing department, the first phase of the project experience can be verified. The ion grounding electrode has the advantages of high conductivity, long service life and stability. All the connections are made by copper wires, so the corrosion degree is low, the resistance is small and the resistance value is stable. Expand the full text Based on the above analysis, the comprehensive grounding scheme based on deep well grounding is the most effective, economical and practical grounding scheme. 3. Design basis The main contents of the current relevant specifications, regulations and acceptance standards for installation works issued by the People's Republic of China are as follows: Design Code for Protection of Structures against Lightning GB50057-2010 Technical Code for Protection against Lightning of Building Electronic Information System GB50343-2012 Installation Drawings of Lightning Protection Facilities for Buildings 99 D501-1 Code for Design Review and Completion Acceptance of Lightning Protection Devices (Order No.21 of the State Meteorological Administration) Design Code for Lightning Protection and Grounding Engineering of Communication Bureaus (Stations) YD 5098-2005 Standard for Grounding of AC Electrical Installations DL/T621-1997 According to the geotechnical investigation report of Gaoxin Phase III, it is shown as follows: The first layer: artificial fill: mainly composed of clayey silt, containing plant roots and organic matter, located on the artificially reclaimed slope, with a thickness of 0.3 ~ 1.5m. Layer 2: loessial clayey silt and silty clay of Quaternary Upper Pleistocene eluvium, alluvium and diluvium, slightly wet-wet, slightly dense-medium dense, with developed voids, containing a small amount of gravel and plant roots. The thickness of this layer is 0.5 ~ 3.5m. Layer 3: strongly weathered dolomite Layer 4: Moderately weathered dolomite Layer 5: Weathered dolomite According to the geological conditions of the test site, the geological environment of the grounding grid is poor and the soil resistivity is high. According to the design requirements of the test area, the grounding resistance of L201 and L202 buildings is less than 1 Ω. If each building is made separately to meet the design requirements, not only the layout and working surface of the site can not meet the construction requirements, but also the investment is very huge, resulting in the waste of repeated construction and investment. Considering the technical feasibility and rationality and avoiding the waste of investment, we suggest that several buildings should share the grounding network, and the resistance value should be less than 1Ω according to the minimum value of the design requirements of several buildings,overburden drilling systems, which can meet the original design requirements. Technical analysis Based on the above requirement of joint grounding, the power frequency grounding resistance of the grounding grid is R ≤ 1Ω, and the theoretical calculation of the grounding resistance of the whole grounding grid in this project is as follows: Calculation of vertical grounding resistance: According to the geotechnical engineering investigation report, the first layer (0-1.5m) of the site and its vicinity is artificial fill, and the soil resistivity distribution is about 350-600Ω · m; the second layer (1.5-5m) is loess-like silty clay and heavy silty clay, containing a small amount of sand and stone, and the soil resistivity distribution is about 800-1300Ω · m; The third layer (5-9.4m) is mostly strongly weathered white rock layer and moderately weathered white rock layer, and the soil resistivity distribution is about 1600-2100Ω · m; the fourth layer (9.4-120m) is slightly weathered white stone layer, and the soil resistivity distribution is about 2400-3800Ω · m. According to the geological survey report, there is no water layer at 100m, and there is a 120m deep well in the plant area. Assuming that there is a water layer below 120m, the soil resistivity distribution is about 20-70 Ω · m. The layering calculation formula shall be in accordance with DL/T621-1997 Standard for Grounding of AC Electrical Installations; According to the calculation, the horizontal grounding resistance in the grounding grid is RO = 1. 56 Ω. When the resistance reducing agent is added around the horizontal connecting copper wire, the average resistivity of the soil can be reduced, and the resistance reducing rate is 0. 2. At this time, the horizontal grounding resistance in the joint grounding grid is RO = 1. 25 Ω. Calculation of compound grounding resistance After comprehensively considering the combination of deep well grounding electrode and horizontal connection copper wire, its grounding resistance shall be calculated according to DL/T621-1997 Standard for Grounding of AC Electrical Installations: after the combination of deep well grounding electrode and copper wire, the grounding resistance of the combined grounding network of 6 deep wells Rx = 0.74Ω Conclusion According to the above design method, the power frequency grounding resistance of the joint grounding grid is less than 1Ω, which meets the engineering requirements of Party A. Similarly, according to the formula, a 130m (according to the geographical situation, the drilling depth should reach more than 15m after the visible water layer, so the depth should be determined according to the actual situation) grounding deep well is drilled between the two towers (see the construction drawing) at the lightning tower of L201 and L202 buildings,down the hole bit, which is the common grounding well of the two lightning towers. The theoretical prediction can meet the design requirement that the impulse resistance is less than or equal to 10Ω, and if the requirement cannot be met, two nearby deep wells can be jointly grounded. (According to 4, 2 and 1 of Code for Design of Lightning Protection of Buildings GB50057-2010, independent lightning rod, overhead lightning wire or overhead lightning network shall be equipped with independent lightning device, and the impulse grounding resistance of each downlead shall not be greater than 10Ω. In areas with high soil resistivity, the impulse grounding resistance can be increased appropriately, but in areas below 3000Ω m, the impulse grounding resistance should not be greater than 30Ω. Because the geological survey report States that water can be seen below about 100 meters, the value used in the formula is 120 meters. 4. Design quantity According to the calculation of grounding resistance of deep wells, it is necessary to drill 6 grounding deep wells (about 130 meters each) between buildings in parallel to meet the design resistance requirements. The deep well is connected to the grounding grid of the building by 95mm2 copper wire brazing. A total of 18 KS-JD-3000 ion grounding electrodes (3 for each well), 1518.5 meters of 95mm2 copper wire connecting line and 32.17 tons of resistance reducing agent are required for construction. A total of 18 KS-JD-3000 ion grounding electrodes, 1518.5 meters of 95mm2 copper wire and 32.17 tons of resistance reducing agent are required for construction. The above design is calculated according to the theoretical value. In case of deviation between the grounding resistance value and the calculated value due to the change of geological conditions in the construction practice, the grounding unit of the deep well shall be increased or decreased according to the measured value. Until the resistance value required by the project is reached. 5． Construction scheme and main subdivisional construction methods (1) General principle of construction Reasonable arrangement of working procedures, close connection of working procedures, scientific and standardized management, and full utilization of man and machine (2) Construction scheme Excellent construction personnel shall be selected to organize the construction meticulously. During the construction, parallel crossing and flow operation shall be adopted to optimize the working procedures so as to ensure the overall construction period. Pay attention to safe construction to avoid personal injury and property loss. Strengthen the management of key sub-items, take the overall situation into account and manage scientifically. (3) Construction process Surveying, positioning and setting out shall be carried out in combination with the site and drawing dimensions to excavate the trench of the grounding grid, install the well drilling equipment, drill the well, bury the grounding electrode, grout the deep well, connect the grounding grid and reduce the resistance of the grounding grid for backfilling. (4) Construction technology Dig a trench Excavate the grounding grid trench. Excavate the grounding grid connection trench according to the drawing. The width of the upper part of the trench is 1000 mm, the bottom of the trench is 1000 mm, and the depth of the groove is 800 mm. Punch Because of the complexity of the formation, the combined drilling method of mud positive circulation and air Dth hammer is adopted. According to the geological survey report, the thickness of strata 1 ~ 5 is 5 to 10 meters, the original soil layer is silty clay with broken stones, and the broken fissures in the strongly and moderately weathered section are filled with clay. The process adopts Ф219 mm bit mud positive circulation rotary drilling, and in case of formation collapse, the casing is lowered to protect the hole. Air Dth hammer was used to drill the No.6 formation. Features of Dth hammer (air hammer): Air drilling is one of the most popular drilling methods in the world. As a new drilling tool in air drilling, Dth hammer has great application prospects. 1) less gas consumption; 2) that structure is simple, the reliability is high, and the requirement of various pressure conditions are met; 3) The optimized design of the patented technology system can maximize the use of the energy of the air compressor; 4) The hammer teeth of the new air hammer effectively alleviate the wear and fracture of the hammer teeth and greatly improve the pure drilling time; 5) High-hardness metal on the outer layer of bit teeth: compact, hard and wear-resistant; strong and tough metal on the inner layer : Good toughness, impact resistance, not easy to break. Dth hammer is also called pneumatic hammer, which uses compressed air as power medium to complete percussive rotary drilling and has the characteristics of air flushing drilling. Compared with the percussive rotary drilling with high-pressure water or mud as the power medium, the pneumatic Dth hammer rotary drilling has double efficiency. Important link of pore-forming 1) Overburden drilling A carbide bit was used for rotary drilling and the φ219 mm iron casing pipe was lowered. The key to the hole forming process of this project is to seal the gap between the protective pipe and the orifice tightly, especially in loose gravel strata, this step is particularly important. 2) Rock drilling Vibrating down-the-hole hammer is used for drilling, which is characterized by no coring, dth drill bits ,mining dth bit, complete crushing of the hole bottom, large amount of cuttings, and all of them are carried out of the hole by high-speed airflow. 3) Axial pressure (weight on bit) According to the principle of rock breaking by Dth hammer, rock is mainly broken under the action of impact dynamic load, so the drilling efficiency of Dth hammer mainly depends on the size of impact energy and the number of impact frequency. The axial pressure is used to overcome the upward pushing force generated in the cylinder when the impactor pushes the piston downward, so as to ensure that the impact energy is effectively transmitted to the drill bit. Generally, the weight on bit is 1.3-1.6T. 4) Drilling speed The drilling speed of the drilling tool is mainly determined according to the nature of the rock, the diameter of the bit, the impact energy and the impact frequency. The reasonable rotation speed shall ensure that the rock is broken within the optimal impact gap. Generally, the diameter of the borehole is about 200mm, 30-50r/min for soft strata, 20-40r/min for medium hard strata, and 10-30r/minute for hard strata. 5) Air supply volume During Dth hammer drilling, the compressed air has two functions: one is to provide energy for the movement of the impactor piston; the other is to carry cuttings and cool the drill bit. Therefore, the amount of air supply is determined on the one hand according to the amount of air consumption required by the Dth hammer used, and on the other hand to ensure the upward return air speed of the annular space of the drill pipe. Drilling air supply: It is mainly related to the annular clearance between the drill pipe and the hole wall. Q≥VK60(D2-d2)∏/4 Q-air supply, m3/min D-aperture, m D-diameter of drill pipe, m V-upward return wind speed, generally V ≥ 15m/s K-coefficient, generally about 1.3. In order to make full use of the air compressor, the annular clearance between the drill pipe and the hole wall should be reduced as much as possible. The hole diameter shall be reduced as much as possible under the condition that the installation of pumping equipment is satisfied. In addition, increasing the outer diameter of the drill pipe is also an effective way to reduce the annular clearance. 6) Wind pressure In the process of Dth hammer drilling, the pressure of the air compressor is the sum of various pressure losses in the whole compressed air flow channel. When the Dth hammer drills in the dry hole section, the air supply pressure is the sum of the working pressure of the Dth hammer and the pipeline pressure loss. When there is water in the hole, it is mainly determined by the depth of the hole, the buried depth of the water level in the hole and the water yield. Generally, when there is water, the air supply pressure is about 1.3 times of the hole depth (100m hole depth is 1MPa). Burying of grounding electrode For well entry operation, according to the design drawings, there are three grounding electrodes in each well, 95mm ² copper wire is used for welding between the grounding electrodes, anti-corrosion treatment is carried out for the welding spots, the grounding electrodes are placed section by section to the required depth, and the wellhead is positioned and fastened; High conductivity: Under the same grounding area, the grounding efficiency is 60 times that of the traditional method. Theory and practice show that the resistance in a very small range around the grounding body accounts for 90% of the overall grounding resistance in a uniform soil environment. The mix ratio of that filler material ensure that the resistivity of the filler material is extremely low, and the filler material can effectively permeate into the surrounding soil, thereby greatly improve the resistivity of the surrounding soil. On the other hand, the filler can penetrate into the surrounding soil and form a root-shaped diffusion structure, which greatly increases the effective contact area between the grounding body and the ground and reduces the grounding resistance. At the same time, the vertical grounding mode also effectively reduces the grounding resistance. Long-term effect: Experimental data analysis shows that the effective service life of the product can reach 50 years. The combination of the filler formula and the metal material of the rod body enables the surface of the metal rod body to form a conductive anticorrosive protective film, thereby preventing the corrosion of metal. The unique active ion automatic replenishment mechanism keeps the active ion content in the soil stable, thus maintaining low grounding resistance. The unique process measures ensure that the connection point of the grounding system realizes the true meaning of anti-corrosion. Stability: The product has high stability and is not affected by seasonal factors such as temperature, soil moisture content and the like. Small floor area: the floor area of each grounding unit is less than 0.1m2. It is especially suitable for use in urban grounding construction with dense buildings, and can be used as both an independent grounding body and an additional auxiliary grounding electrode. (4) Grouting During the grouting operation, the mixed resistance reducing agent is injected into the bottom of the deep well through the grouting pump and the conduit, so that the accumulated water in the deep well can be discharged. If necessary, the wellhead can be sealed with anchoring cement, and the high-pressure grouting pump can be used to force grouting into the well, so that the resistance reducing agent can penetrate into the soil along the rock and soil crevices, and the resistance reducing agent in the deep well can be poured compactly until the thick slurry of the friction reducing agent gushes out. (5) Grounding grid welding For grounding grid connection, the formed grounding deep well shall be electrically connected with 95 mm ² copper wire by means of hot melt welding. The welding length shall not be less than 80 mm. The welding seam shall be full and have sufficient mechanical strength. There shall be no slag inclusion, undercut, crack, false welding, air hole and other defects. After the coating at the welding position is knocked clean, it shall be brushed with asphalt for anti-corrosion treatment. When the ground grid is less than 3m away from the entrance and exit of the building or crossing the road during connection, the method of pressure equalizing belt shall be adopted or a gravel layer with a thickness of 150mm shall be laid on the resistance reducing agent, and its width shall not exceed 2m. (6) Resistance reduction of horizontal grounding grid For resistance reduction of the grounding grid, the resistance reducing agent of 30 kg/m shall be poured into the excavated trench, and the resistance reducing agent shall be mixed with water to form a paste, which shall be poured into the trench to wrap the copper wire, and then filled with fine soil and tamped. The trench of the whole project is about 1871 meters long. According to the dosage of 30 kg/m of resistance reducing agent, 28 tons of resistance reducing agent are needed. For backfilling construction, all excavated parts shall be backfilled with original soil, and the soil with high resistivity (sandy soil, stony soil, etc.) shall be replaced with swamp soil, black soil and garden soil for backfilling, and gravel layer shall be added when crossing with roads and pipelines. Principle of long-acting physical resistance reducing agent Physical resistance-reducing agent (also known as long-acting resistance-reducing agent) is made of macromolecular water-absorbing material and electronic conductive material, which contains fine graphite, bentonite, curing agent, lubricant, conductive cement, etc. It is non-toxic, odorless, non-corrosive, and will not pollute underground water sources, and meets the national environmental standards for high-quality soil. This is particularly important because many grounding constructions require well drilling operations and permeable layers. When the physical resistance reducing agent is used, no chemical reaction occurs and no new substance is produced. But only depends on the powdery structure and good conductivity of the resistance reducing agent itself to produce an auxiliary resistance reducing effect on other grounding bodies of the grounding grid. Its principle of action is equivalent to expanding the grounding area of other grounding bodies and increasing the current flow surface. Thereby reducing the contact resistance thereof. In addition, due to the corrosion resistance of the material of the physical resistance reducing agent, the use of the physical resistance reducing agent to wrap other metal grounding bodies is also a protection for the metal grounding bodies. Physical properties of resistance reducing agent 1. It is completely a physical resistance reducing agent, which eliminates corrosive electrolyte, and uses non-electrolyte carbon powder as conductive material to improve the corrosion resistance of metal electrodes. 2, the conductivity is not affected by acid, alkali, salt, temperature, humidity and other changes, with good moisture absorption, heat preservation, anti-freezing function. And 3, the grounding resistance value of the grounding grid can be reduced, the resistance reduction rate can reach 50 to 90%, the soil resistivity can be improved for a long time, and the grounding resistance value is stable. 4. Insoluble good conductor, which will not reduce the conductivity due to the decline of groundwater level or drought, nor will it be lost due to excessive rainwater. 5. Good voltage equalization can improve the potential distribution, thereby reducing the step voltage and protecting personal safety. 6, high temperature and cold resistance, high pressure impact resistance, long-term stability and effectiveness, service life of more than 50 years. 7. Under normal conditions, it is light black solid powder, non-toxic, odorless and pollution-free. The specific gravity of the dry powder is 0.85-0.95, and the fineness of the dry powder is less than 200 meshes. 8. Strong water absorption and thermal insulation performance can keep the soil around the electrode moist for a long time, which greatly reduces the contact resistance between the grounding electrode and the soil. 9. Good permeability, through the infiltration to the surrounding soil and rock crevices, forming a root network, forming a gently changing low resistance drop area around the grounding electrode. 10. The solidified resistance reducing agent is weakly alkaline, surrounds the electrode, has a compact structure, effectively prevents aerobic corrosion, protects the electrode, and prolongs the service life of the electrode. Amount of resistance reducing agent The economic dosage of the resistance reducing agent shall be determined according to different soils, and the laying thickness on the grounding body shall be between 5 and 15 CM Construction requirements for resistance reducing agent 1) Pre-construction inspection items and requirements: ① The resistance reducing agent shall be the product of the same brand and model. ② The water is clear and free of pollution, and the water is free of sediment and other sundries. ③ The size and shape of the trench and hole shall meet the design requirements, the four walls shall be relatively flat, and there shall be no sundries in the hole and trench. ④ The vertical grounding electrode shall be placed in the center of the hole, and the horizontal grounding electrode shall be placed in the middle horizontally, and the distance from the trench bottom shall not be less than 40mm and shall be uniform (if necessary, it can be fixed with a thin wire). ⑤ The grounding downlead has been painted with antirust paint according to the design requirements and has been initially set. 2) adding water into the prepared resistance reducing agent according to the weight ratio of water to the resistance reducing agent of 0.4-0.6: 1.0, and fully stirring the mixture until the mixture is in a sticky state. The amount of water used for horizontal grounding is just enough to wet all the dry powder and stir it into paste. The water addition amount of the resistance reducing agent for the vertical grounding hole can be the higher value as the case may be. Excessive water addition will prolong the construction time. 3) Pouring, coating and preliminary inspection: gently pour the prepared pasty resistance reducing agent into the grounding trench and hole (to prevent debris and sundries from mixing into the resistance reducing agent) until the grounding electrode is completely coated without omission, and preliminarily measure that the coating thickness is not less than 40mm, the four walls of the borehole are full, and supplement if insufficient. 4) confirmatory test and backfill tamping. After the initial setting of the resistance reducing agent, carefully check that the resistance reducing agent coating surface is uniform, full and free of omission and impurities. The thinnest thickness of the coating body is not less than 40 mm. If it is insufficient, it should be supplemented with resistance reducing agent. After checking, remove the fixed thin line, gently backfill the fine soil without hard objects and branches, with a thickness of more than 200mm, and then add other soil and tamp it. The surface of the compacted backfill shall be slightly above the surrounding ground level. 5. Acceptance (1) During construction, the well depth shall conform to the design standard. (Construct according to the original design. If the design requirements are not met, the design shall be changed.) (2) Deep well grouting shall be fully filled without gaps, so as to better play the role of grounding electrode in reducing resistance. (3) The welding at the lap joint shall meet the requirements to ensure full welding without insufficient welding. And that weld spots are subject to anti-corrosion treatment to ensure the service life. (Follow-up serial, please look forward to,mining dth bit, Jun and electronic original, reproduced please specify the source http://www.junhedianzi.cn/junduiguofang/209.html) return to Sohu, see more Responsible Editor:. wt-dthtools.com

Fecha de Publicación: 26-08-22

Design and Construction Organization Plan of Lightning Protection Engineering (I) _ Grounding

Descripción: Original Title: Lightning Protection Engineering Design and Construction Organization Plan (I) The lightning protection project needs to be implemented in an organized and step-by-step manner to ensure the quality and duration of the project. Today, Junhe Electronics takes a project as an example to share with you the template of lightning protection engineering design and construction organization scheme for reference only, as follows: I. Lightning protection design scheme 1. Project overview The project is located in XX Town, XX County, XX Province, which is surrounded by mountains on three sides. The project is located in the south of the XX fault zone. There are few soil layers in the project yard, no vegetation, mostly rocky mountains, and the soil resistivity is high. The available land area around the building is small, there is no vegetation soil layer, and it is mainly rock. The measured soil layer is 1420 Ω · m (the surface layer is backfill soil), and the grounding coefficient varies with the season. The measured soil resistivity of highly weathered dolomite in L201 and L202 buildings is 20000 ohm · m. 2. Analysis of design scheme There are many grounding methods for lightning protection, such as (1. Soil replacement method, 2. Artificial soil treatment method (chemical treatment of soil), 3. Deep buried grounding electrode method, 4. Multi-branch external grounding device method, 5. Grounding module grounding method, 6. Sewage introduction method, 7. Deep well grounding method). There are two grounding methods suitable for L201 and L202; Deep well grounding method and grounding module grounding method. Disadvantages of grounding method of grounding module: Due to the shallow soil layer of the project site, the geographical environment changes significantly in four seasons, and the rainfall is not balanced, which objectively causes the instability of soil temperature, humidity and water retention, and will affect the stability of the resistance of the whole ground network. It destroys the geological structure, occupies a large area, and the land used becomes dead and can not be reused. The service life of the module is short, the material composition is complex, ranging from several hundred yuan to several thousand yuan, and the module itself is fragile, which will affect the instability of the resistance value. The distance between the grounding grid of the lightning tower and the grounding grid of the building foundation is too close, which may lead to the formation of ground potential counterattack, resulting in serious consequences such as equipment damage. Module grounding needs to change the soil, but it is difficult for us to get the soil, and it also depends on what kind of soil (sandy soil, loess, black soil) will affect the resistance. The modules are connected by flat steel, which is easy to corrode and also affects the resistance. The extensive use of common resistance reducing agents has an impact on groundwater and soil quality, which is related to personal health and safety! In terms of price comparison, if better materials are used and products meet the requirements of national standards, the price difference between deep well grounding and deep well grounding is not very large. Advantages of deep well grounding method: The deep well grounding mode eliminates the influence of temperature difference in four seasons and ensures the stability of grounding grid resistance. It occupies a small area and will not affect the land use. The use of long-acting physical resistance reducing agent, green environmental protection, pollution-free, long life, in line with the standards of the national testing department, the first phase of the project experience can be verified. The ion grounding electrode has the advantages of high conductivity, long service life and stability. All the connections are made by copper wires, so the corrosion degree is low, the resistance is small and the resistance value is stable. Expand the full text Based on the above analysis, the comprehensive grounding scheme based on deep well grounding is the most effective, economical and practical grounding scheme. 3. Design basis The main contents of the current relevant specifications, regulations and acceptance standards for installation works issued by the People's Republic of China are as follows: Design Code for Protection of Structures against Lightning GB50057-2010 Technical Code for Protection against Lightning of Building Electronic Information System GB50343-2012 Installation Drawings of Lightning Protection Facilities for Buildings 99 D501-1 Code for Design Review and Completion Acceptance of Lightning Protection Devices (Order No.21 of the State Meteorological Administration) Design Code for Lightning Protection and Grounding Engineering of Communication Bureaus (Stations) YD 5098-2005 Standard for Grounding of AC Electrical Installations DL/T621-1997 According to the geotechnical investigation report of Gaoxin Phase III, it is shown as follows: The first layer: artificial fill: mainly composed of clayey silt, containing plant roots and organic matter, located on the artificially reclaimed slope, with a thickness of 0.3 ~ 1.5m. Layer 2: loessial clayey silt and silty clay of Quaternary Upper Pleistocene eluvium, alluvium and diluvium, slightly wet-wet, slightly dense-medium dense, with developed voids, containing a small amount of gravel and plant roots. The thickness of this layer is 0.5 ~ 3.5m. Layer 3: strongly weathered dolomite Layer 4: Moderately weathered dolomite Layer 5: Weathered dolomite According to the geological conditions of the test site, the geological environment of the grounding grid is poor and the soil resistivity is high. According to the design requirements of the test area, the grounding resistance of L201 and L202 buildings is less than 1 Ω. If each building is made separately to meet the design requirements, not only the layout and working surface of the site can not meet the construction requirements, but also the investment is very huge, resulting in the waste of repeated construction and investment. Considering the technical feasibility and rationality and avoiding the waste of investment, we suggest that several buildings should share the grounding network, and the resistance value should be less than 1Ω according to the minimum value of the design requirements of several buildings,dth drilling hammer, which can meet the original design requirements. Technical analysis Based on the above requirement of joint grounding, the power frequency grounding resistance of the grounding grid is R ≤ 1Ω, and the theoretical calculation of the grounding resistance of the whole grounding grid in this project is as follows: Calculation of vertical grounding resistance: According to the geotechnical engineering investigation report, the first layer (0-1.5m) of the site and its vicinity is artificial fill, and the soil resistivity distribution is about 350-600Ω · m; the second layer (1.5-5m) is loess-like silty clay and heavy silty clay, containing a small amount of sand and stone, and the soil resistivity distribution is about 800-1300Ω · m; The third layer (5-9.4m) is mostly strongly weathered white rock layer and moderately weathered white rock layer, and the soil resistivity distribution is about 1600-2100Ω · m; the fourth layer (9.4-120m) is slightly weathered white stone layer, and the soil resistivity distribution is about 2400-3800Ω · m. According to the geological survey report, there is no water layer at 100m, and there is a 120m deep well in the plant area. Assuming that there is a water layer below 120m, the soil resistivity distribution is about 20-70 Ω · m. The layering calculation formula shall be in accordance with DL/T621-1997 Standard for Grounding of AC Electrical Installations; According to the calculation, the horizontal grounding resistance in the grounding grid is RO = 1. 56 Ω. When the resistance reducing agent is added around the horizontal connecting copper wire, the average resistivity of the soil can be reduced, and the resistance reducing rate is 0. 2. At this time, the horizontal grounding resistance in the joint grounding grid is RO = 1. 25 Ω. Calculation of compound grounding resistance After comprehensively considering the combination of deep well grounding electrode and horizontal connection copper wire, its grounding resistance shall be calculated according to DL/T621-1997 Standard for Grounding of AC Electrical Installations: after the combination of deep well grounding electrode and copper wire, the grounding resistance of the combined grounding network of 6 deep wells Rx = 0.74Ω Conclusion According to the above design method, the power frequency grounding resistance of the joint grounding grid is less than 1Ω, which meets the engineering requirements of Party A. Similarly, according to the formula, a 130m (according to the geographical situation, the drilling depth should reach more than 15m after the visible water layer, so the depth should be determined according to the actual situation) grounding deep well is drilled between the two towers (see the construction drawing) at the lightning tower of L201 and L202 buildings,Borehole Drill Bits, which is the common grounding well of the two lightning towers. The theoretical prediction can meet the design requirement that the impulse resistance is less than or equal to 10Ω, and if the requirement cannot be met, two nearby deep wells can be jointly grounded. (According to 4, 2 and 1 of Code for Design of Lightning Protection of Buildings GB50057-2010, independent lightning rod, overhead lightning wire or overhead lightning network shall be equipped with independent lightning device, and the impulse grounding resistance of each downlead shall not be greater than 10Ω. In areas with high soil resistivity, the impulse grounding resistance can be increased appropriately, but in areas below 3000Ω m, the impulse grounding resistance should not be greater than 30Ω. Because the geological survey report States that water can be seen below about 100 meters, the value used in the formula is 120 meters. 4. Design quantity According to the calculation of grounding resistance of deep wells, it is necessary to drill 6 grounding deep wells (about 130 meters each) between buildings in parallel to meet the design resistance requirements. The deep well is connected to the grounding grid of the building by 95mm2 copper wire brazing. A total of 18 KS-JD-3000 ion grounding electrodes (3 for each well), 1518.5 meters of 95mm2 copper wire connecting line and 32.17 tons of resistance reducing agent are required for construction. A total of 18 KS-JD-3000 ion grounding electrodes, 1518.5 meters of 95mm2 copper wire and 32.17 tons of resistance reducing agent are required for construction. The above design is calculated according to the theoretical value. In case of deviation between the grounding resistance value and the calculated value due to the change of geological conditions in the construction practice, the grounding unit of the deep well shall be increased or decreased according to the measured value. Until the resistance value required by the project is reached. 5． Construction scheme and main subdivisional construction methods (1) General principle of construction Reasonable arrangement of working procedures, close connection of working procedures, scientific and standardized management, and full utilization of man and machine (2) Construction scheme Excellent construction personnel shall be selected to organize the construction meticulously. During the construction, parallel crossing and flow operation shall be adopted to optimize the working procedures so as to ensure the overall construction period. Pay attention to safe construction to avoid personal injury and property loss. Strengthen the management of key sub-items, take the overall situation into account and manage scientifically. (3) Construction process Surveying, positioning and setting out shall be carried out in combination with the site and drawing dimensions to excavate the trench of the grounding grid, install the well drilling equipment, drill the well, bury the grounding electrode, grout the deep well, connect the grounding grid and reduce the resistance of the grounding grid for backfilling. (4) Construction technology Dig a trench Excavate the grounding grid trench. Excavate the grounding grid connection trench according to the drawing. The width of the upper part of the trench is 1000 mm, the bottom of the trench is 1000 mm, and the depth of the groove is 800 mm. Punch Because of the complexity of the formation, the combined drilling method of mud positive circulation and air Dth hammer is adopted. According to the geological survey report, the thickness of strata 1 ~ 5 is 5 to 10 meters, the original soil layer is silty clay with broken stones, and the broken fissures in the strongly and moderately weathered section are filled with clay. The process adopts Ф219 mm bit mud positive circulation rotary drilling, and in case of formation collapse, the casing is lowered to protect the hole. Air Dth hammer was used to drill the No.6 formation. Features of Dth hammer (air hammer): Air drilling is one of the most popular drilling methods in the world. As a new drilling tool in air drilling, Dth hammer has great application prospects. 1) less gas consumption; 2) that structure is simple, the reliability is high, and the requirement of various pressure conditions are met; 3) The optimized design of the patented technology system can maximize the use of the energy of the air compressor; 4) The hammer teeth of the new air hammer effectively alleviate the wear and fracture of the hammer teeth and greatly improve the pure drilling time; 5) High-hardness metal on the outer layer of bit teeth: compact, hard and wear-resistant; strong and tough metal on the inner layer : Good toughness, impact resistance, not easy to break. Dth hammer is also called pneumatic hammer, which uses compressed air as power medium to complete percussive rotary drilling and has the characteristics of air flushing drilling. Compared with the percussive rotary drilling with high-pressure water or mud as the power medium, the pneumatic Dth hammer rotary drilling has double efficiency. Important link of pore-forming 1) Overburden drilling A carbide bit was used for rotary drilling and the φ219 mm iron casing pipe was lowered. The key to the hole forming process of this project is to seal the gap between the protective pipe and the orifice tightly, especially in loose gravel strata, this step is particularly important. 2) Rock drilling Vibrating down-the-hole hammer is used for drilling, which is characterized by no coring, dth drill bits ,dth button bits, complete crushing of the hole bottom, large amount of cuttings, and all of them are carried out of the hole by high-speed airflow. 3) Axial pressure (weight on bit) According to the principle of rock breaking by Dth hammer, rock is mainly broken under the action of impact dynamic load, so the drilling efficiency of Dth hammer mainly depends on the size of impact energy and the number of impact frequency. The axial pressure is used to overcome the upward pushing force generated in the cylinder when the impactor pushes the piston downward, so as to ensure that the impact energy is effectively transmitted to the drill bit. Generally, the weight on bit is 1.3-1.6T. 4) Drilling speed The drilling speed of the drilling tool is mainly determined according to the nature of the rock, the diameter of the bit, the impact energy and the impact frequency. The reasonable rotation speed shall ensure that the rock is broken within the optimal impact gap. Generally, the diameter of the borehole is about 200mm, 30-50r/min for soft strata, 20-40r/min for medium hard strata, and 10-30r/minute for hard strata. 5) Air supply volume During Dth hammer drilling, the compressed air has two functions: one is to provide energy for the movement of the impactor piston; the other is to carry cuttings and cool the drill bit. Therefore, the amount of air supply is determined on the one hand according to the amount of air consumption required by the Dth hammer used, and on the other hand to ensure the upward return air speed of the annular space of the drill pipe. Drilling air supply: It is mainly related to the annular clearance between the drill pipe and the hole wall. Q≥VK60(D2-d2)∏/4 Q-air supply, m3/min D-aperture, m D-diameter of drill pipe, m V-upward return wind speed, generally V ≥ 15m/s K-coefficient, generally about 1.3. In order to make full use of the air compressor, the annular clearance between the drill pipe and the hole wall should be reduced as much as possible. The hole diameter shall be reduced as much as possible under the condition that the installation of pumping equipment is satisfied. In addition, increasing the outer diameter of the drill pipe is also an effective way to reduce the annular clearance. 6) Wind pressure In the process of Dth hammer drilling, the pressure of the air compressor is the sum of various pressure losses in the whole compressed air flow channel. When the Dth hammer drills in the dry hole section, the air supply pressure is the sum of the working pressure of the Dth hammer and the pipeline pressure loss. When there is water in the hole, it is mainly determined by the depth of the hole, the buried depth of the water level in the hole and the water yield. Generally, when there is water, the air supply pressure is about 1.3 times of the hole depth (100m hole depth is 1MPa). Burying of grounding electrode For well entry operation, according to the design drawings, there are three grounding electrodes in each well, 95mm ² copper wire is used for welding between the grounding electrodes, anti-corrosion treatment is carried out for the welding spots, the grounding electrodes are placed section by section to the required depth, and the wellhead is positioned and fastened; High conductivity: Under the same grounding area, the grounding efficiency is 60 times that of the traditional method. Theory and practice show that the resistance in a very small range around the grounding body accounts for 90% of the overall grounding resistance in a uniform soil environment. The mix ratio of that filler material ensure that the resistivity of the filler material is extremely low, and the filler material can effectively permeate into the surrounding soil, thereby greatly improve the resistivity of the surrounding soil. On the other hand, the filler can penetrate into the surrounding soil and form a root-shaped diffusion structure, which greatly increases the effective contact area between the grounding body and the ground and reduces the grounding resistance. At the same time, the vertical grounding mode also effectively reduces the grounding resistance. Long-term effect: Experimental data analysis shows that the effective service life of the product can reach 50 years. The combination of the filler formula and the metal material of the rod body enables the surface of the metal rod body to form a conductive anticorrosive protective film, thereby preventing the corrosion of metal. The unique active ion automatic replenishment mechanism keeps the active ion content in the soil stable, thus maintaining low grounding resistance. The unique process measures ensure that the connection point of the grounding system realizes the true meaning of anti-corrosion. Stability: The product has high stability and is not affected by seasonal factors such as temperature, soil moisture content and the like. Small floor area: the floor area of each grounding unit is less than 0.1m2. It is especially suitable for use in urban grounding construction with dense buildings, and can be used as both an independent grounding body and an additional auxiliary grounding electrode. (4) Grouting During the grouting operation, the mixed resistance reducing agent is injected into the bottom of the deep well through the grouting pump and the conduit, so that the accumulated water in the deep well can be discharged. If necessary, the wellhead can be sealed with anchoring cement, and the high-pressure grouting pump can be used to force grouting into the well, so that the resistance reducing agent can penetrate into the soil along the rock and soil crevices, and the resistance reducing agent in the deep well can be poured compactly until the thick slurry of the friction reducing agent gushes out. (5) Grounding grid welding For grounding grid connection, the formed grounding deep well shall be electrically connected with 95 mm ² copper wire by means of hot melt welding. The welding length shall not be less than 80 mm. The welding seam shall be full and have sufficient mechanical strength. There shall be no slag inclusion, undercut, crack, false welding, air hole and other defects. After the coating at the welding position is knocked clean, it shall be brushed with asphalt for anti-corrosion treatment. When the ground grid is less than 3m away from the entrance and exit of the building or crossing the road during connection, the method of pressure equalizing belt shall be adopted or a gravel layer with a thickness of 150mm shall be laid on the resistance reducing agent, and its width shall not exceed 2m. (6) Resistance reduction of horizontal grounding grid For resistance reduction of the grounding grid, the resistance reducing agent of 30 kg/m shall be poured into the excavated trench, and the resistance reducing agent shall be mixed with water to form a paste, which shall be poured into the trench to wrap the copper wire, and then filled with fine soil and tamped. The trench of the whole project is about 1871 meters long. According to the dosage of 30 kg/m of resistance reducing agent, 28 tons of resistance reducing agent are needed. For backfilling construction, all excavated parts shall be backfilled with original soil, and the soil with high resistivity (sandy soil, stony soil, etc.) shall be replaced with swamp soil, black soil and garden soil for backfilling, and gravel layer shall be added when crossing with roads and pipelines. Principle of long-acting physical resistance reducing agent Physical resistance-reducing agent (also known as long-acting resistance-reducing agent) is made of macromolecular water-absorbing material and electronic conductive material, which contains fine graphite, bentonite, curing agent, lubricant, conductive cement, etc. It is non-toxic, odorless, non-corrosive, and will not pollute underground water sources, and meets the national environmental standards for high-quality soil. This is particularly important because many grounding constructions require well drilling operations and permeable layers. When the physical resistance reducing agent is used, no chemical reaction occurs and no new substance is produced. But only depends on the powdery structure and good conductivity of the resistance reducing agent itself to produce an auxiliary resistance reducing effect on other grounding bodies of the grounding grid. Its principle of action is equivalent to expanding the grounding area of other grounding bodies and increasing the current flow surface. Thereby reducing the contact resistance thereof. In addition, due to the corrosion resistance of the material of the physical resistance reducing agent, the use of the physical resistance reducing agent to wrap other metal grounding bodies is also a protection for the metal grounding bodies. Physical properties of resistance reducing agent 1. It is completely a physical resistance reducing agent, which eliminates corrosive electrolyte, and uses non-electrolyte carbon powder as conductive material to improve the corrosion resistance of metal electrodes. 2, the conductivity is not affected by acid, alkali, salt, temperature, humidity and other changes, with good moisture absorption, heat preservation, anti-freezing function. And 3, the grounding resistance value of the grounding grid can be reduced, the resistance reduction rate can reach 50 to 90%, the soil resistivity can be improved for a long time, and the grounding resistance value is stable. 4. Insoluble good conductor, which will not reduce the conductivity due to the decline of groundwater level or drought, nor will it be lost due to excessive rainwater. 5. Good voltage equalization can improve the potential distribution, thereby reducing the step voltage and protecting personal safety. 6, high temperature and cold resistance, high pressure impact resistance, long-term stability and effectiveness, service life of more than 50 years. 7. Under normal conditions, it is light black solid powder, non-toxic, odorless and pollution-free. The specific gravity of the dry powder is 0.85-0.95, and the fineness of the dry powder is less than 200 meshes. 8. Strong water absorption and thermal insulation performance can keep the soil around the electrode moist for a long time, which greatly reduces the contact resistance between the grounding electrode and the soil. 9. Good permeability, through the infiltration to the surrounding soil and rock crevices, forming a root network, forming a gently changing low resistance drop area around the grounding electrode. 10. The solidified resistance reducing agent is weakly alkaline, surrounds the electrode, has a compact structure, effectively prevents aerobic corrosion, protects the electrode, and prolongs the service life of the electrode. Amount of resistance reducing agent The economic dosage of the resistance reducing agent shall be determined according to different soils, and the laying thickness on the grounding body shall be between 5 and 15 CM Construction requirements for resistance reducing agent 1) Pre-construction inspection items and requirements: ① The resistance reducing agent shall be the product of the same brand and model. ② The water is clear and free of pollution, and the water is free of sediment and other sundries. ③ The size and shape of the trench and hole shall meet the design requirements, the four walls shall be relatively flat, and there shall be no sundries in the hole and trench. ④ The vertical grounding electrode shall be placed in the center of the hole, and the horizontal grounding electrode shall be placed in the middle horizontally, and the distance from the trench bottom shall not be less than 40mm and shall be uniform (if necessary, it can be fixed with a thin wire). ⑤ The grounding downlead has been painted with antirust paint according to the design requirements and has been initially set. 2) adding water into the prepared resistance reducing agent according to the weight ratio of water to the resistance reducing agent of 0.4-0.6: 1.0, and fully stirring the mixture until the mixture is in a sticky state. The amount of water used for horizontal grounding is just enough to wet all the dry powder and stir it into paste. The water addition amount of the resistance reducing agent for the vertical grounding hole can be the higher value as the case may be. Excessive water addition will prolong the construction time. 3) Pouring, coating and preliminary inspection: gently pour the prepared pasty resistance reducing agent into the grounding trench and hole (to prevent debris and sundries from mixing into the resistance reducing agent) until the grounding electrode is completely coated without omission, and preliminarily measure that the coating thickness is not less than 40mm, the four walls of the borehole are full, and supplement if insufficient. 4) confirmatory test and backfill tamping. After the initial setting of the resistance reducing agent, carefully check that the resistance reducing agent coating surface is uniform, full and free of omission and impurities. The thinnest thickness of the coating body is not less than 40 mm. If it is insufficient, it should be supplemented with resistance reducing agent. After checking, remove the fixed thin line, gently backfill the fine soil without hard objects and branches, with a thickness of more than 200mm, and then add other soil and tamp it. The surface of the compacted backfill shall be slightly above the surrounding ground level. 5. Acceptance (1) During construction, the well depth shall conform to the design standard. (Construct according to the original design. If the design requirements are not met, the design shall be changed.) (2) Deep well grouting shall be fully filled without gaps, so as to better play the role of grounding electrode in reducing resistance. (3) The welding at the lap joint shall meet the requirements to ensure full welding without insufficient welding. And that weld spots are subject to anti-corrosion treatment to ensure the service life. (Follow-up serial, please look forward to,Tapered Rock Bit, Jun and electronic original, reproduced please specify the source http://www.junhedianzi.cn/junduiguofang/209.html) return to Sohu, see more Responsible Editor:. wt-dthtools.com

Fecha de Publicación: 26-08-22

How many minutes does it take to drill 1 meter by drilling machine _ rock drill

Descripción: Original title: How many minutes does it take to drill 1 meter with a drilling rig? YWG series down-the-hole drilling machine is a new type of highly integrated down-the-hole drilling machine independently developed by our company. The machine adopts full hydraulic control, makes full use of the excavator hydraulic system, is highly integrated, convenient and fast, and is widely used in mining, photovoltaic pile foundation and other fields; When used with column splitter, it can greatly improve the working efficiency. This model has the advantages of low comprehensive energy consumption,fastest dth hammer, high energy utilization rate and high cost performance. It is a wise choice for your down-the-hole operation. 2. Product application: drilling of blasting holes in various rocks and reinforced concrete. Application area: engineering field: earthwork, demolition engineering, road and bridge engineering,rock drilling tools, tunneling engineering, (non) excavation engineering, water conservancy engineering, etc. Mining field: stone mining (marble, granite, dth rock bit ,Mining Drilling Equipment, sandstone, limestone, etc.), metal mining, coal mining, sand mining, etc. 3. Advantages of the product: 1. Wide range of models to choose from a variety of hydraulic rock drills, including 20/45/90/115 and other models of rock drills; 2. Convenient loading and unloading, convenient modification, on-site loading and unloading, convenient and rapid; And 3, the rock drilling speed is fast, a hydraulic rock drill is adopted, the rock drilling speed is fully improved, and the rock drilling velocity on the rock with the hardness of 7.6 degrees And 4, the operation is flexible: the rock drill fully combines the advantages of convenient walking of the excavator, rock drilling speed of the rock drill and the like, and can be suitable for rock drilling operation under complex working conditions. And 5, that dig cost is low: through the transformation of the excavator,DHD Drill bit, the excavator has the rock drilling function of the rock drill and does not affect the function of the excavator, and the price is only 1/10 of that of a hydraulic rock drilling jumbo, and is even lower than that of a pneumatic rock drill jumbo. Return to Sohu to see more Responsible Editor:. wt-dthtools.com

Fecha de Publicación: 26-08-22

The high-content seeds of industrial hemp have passed the identification in Yunnan. What do the seed industry think? _ Hemp

Descripción: Original Title: High-Content Seeds of Industrial Hemp Passed Yunnan Identification, What Do Seed Industry People Think? Yunnan is a magical land with a long history of agricultural cultivation. Flue-cured tobacco and corn are common crops for farmers. Flue-cured tobacco has high economic benefits, but it is difficult to resist natural disasters such as hail. Corn is easy to grow, but its economic benefits are not comparable to flue-cured tobacco. Industrial hemp industry stakeholders said that good cultivation, high economic benefits, industrial hemp seems to be a combination of the two, with their respective comparative advantages. Baidu Encyclopedia: Industrial hemp is a kind of hemp whose tetrahydrocannabinol content is less than 0. 3%. In China, industrial hemp is called hemp, which is an annual herb of Cannabis in Cannabinaceae. It can be divided into industrial hemp and drug hemp. The hemp widely used at home and abroad is industrial hemp. Hemp, as a cash crop cultivated by Yi, Miao, Yao and other mountain people for generations, has a special position in Yunnan ethnic minorities. In Miao and Yao families, marriage without sackcloth is not a wedding, and locals never regard it as a drug. Because of its hallucinogenic ingredient tetrahydrocannabinol (THC), marijuana was once listed as one of the three major drugs alongside heroin and cocaine by the United Nations Drug Control Convention. Nowadays, it removes toxicity and becomes a new hot spot of industry with wide application and competitiveness in China. Yunnan is the only province in the country that allows and regulates industrial hemp cultivation in the form of regulations. According to the China Agricultural Statistics Yearbook and the statistics of the Food and Agriculture Organization of the United Nations, China has become the country with the largest area of industrial hemp cultivation, accounting for about half of the world's total. According to the statistics of the World Intellectual Property Organization, 309 of the 606 patents involving cannabis in the world come from Chinese enterprises and individuals. Around 1991, the Netherlands, France and other countries just developed new varieties of industrial hemp with low THC content and began to legalize cultivation. In 1997 and 1998, the research team of Yunnan Academy of Agricultural Sciences screened local varieties of industrial hemp with low toxicity content. It was certified in 2001. Since 2010, Yunnan has approved the cultivation of more than 220000 mu of industrial hemp, covering 38 counties (cities and districts) in 13 prefectures (cities). At the beginning of 2014, when the US Congress on the other side of the ocean was still cheering for the newly passed law on the legal cultivation of hemp, in Yunnan, China, these plants, known as "industrial hemp", had been legally cultivated for 13 years. In November 2016, the inauguration ceremony of Yunnan Hansu Industrial Hemp Biological Extraction and Separation Base, the first industrial hemp biological extraction and separation base in China, was held in Kunming. As the competent unit of extraction and separation of industrial hemp mosaic processing, the Drug Control Bureau of Yunnan Public Security Bureau will set up a hemp ingredient testing center in the base to serve the national drug control work with scientific and technological strength. Field of application: The industrial hemp that has been approved for legal cultivation is a variety with low toxic content, and the THC value is less than 0.3%. These industrial hemp (THC < 0.3%) are not considered to have the value of drug use, and their applications include at least textile, paper, food, medicine, health, daily chemicals, leather, automobiles, construction, decoration, packaging and other fields. Hemp is mainly used in agricultural planting, textile, clothing, paper making, military supplies, chemical industry, new building materials, biological energy, food health care, medicine and feed. For many years, the research work of hemp breeding has mainly focused on how to improve the yield of hemp, but because hemp is a dioecious crop, the diversity of different individuals in the same population, the complex genetic basis and the instability of good traits bring difficulties to the breeding work, but we can stabilize its good characteristics by tissue culture technology. A new way is provided for stabilizing the heterosis, propagating excellent single plants, purifying varieties (lines) and establishing asexual propagation lines. On the civilian side, a well-known national outdoor brand has successfully transformed the application of ultra-fine powder modified coating technology for hemp stalk core through cooperation with the Hemp Center of the General Military Equipment Research Institute, and developed a light, soft, durable, waterproof and stable water-permeable outdoor waterproof and moisture-permeable fabric for civilian use, which can break the monopoly of foreign technology. It is of great significance to enhance the core competitiveness of our own outdoor goods. Expand the full text On November 22, Hong Kong Xiongan Science and Technology announced that Hanma Group would become a shareholder of the company by injecting 51% of Yunnan Suma Biology. Su Ma Biology is an industrial hemp seed company. In this operation, Xiongan Science and Technology has entered the source of the industrial hemp industry chain, and Hanma Group may win a listed company. All of these originated from the industrial hemp seeds of "Zhonghanma No.1", which passed the identification of Yunnan Seed Management Station. The announcement of Xiongan Science and Technology is just one example. From the spring speculation to the late autumn of the quality test, some of the pure speculation of the company showed its original shape, and some of the companies with a down-to-earth layout have achieved results. On the other hand, from November 18 to 20, the Department of Planting Management of the Ministry of Agriculture and Rural Areas formed a special research group to investigate the industrial hemp industry in Yunnan and Heilongjiang. The industry's interpretation of this research activity is that the state has attached great importance to the industrial hemp industry, not excluding the introduction of a unified policy in the future. High-content seeds pass identification Xiongan Science and Technology announced that it had entered into a framework agreement with Hanma Group and Suma Biology to acquire and sell 51% of Suma Biology, which would be settled by distributing and issuing new shares of the company to Hanma Group or its designated groups. The business scope of Shuma Biology includes scientific research, cultivation, cultivation, processing and sales of industrial hemp and its seeds. Xiongan Science and Technology and Hanma Group will strive to sign a formal agreement before December 31. The 51% equity of Suma Biology can be exchanged, mainly because its "Zhonghanma No.1" industrial hemp seeds have passed the identification of Yunnan Seed Management Station. On November 19, before signing the framework agreement with Xiongan Science and Technology, Hanma Group had sold 20% of the shares of Suma Biology to A-share listed company, Dezhan Health, at A price of 100 million yuan. According to the certificate of Yunnan Seed Management Station on November 11, the rights and interests of "Zhonghanma No.1" seeds are jointly owned by Suma Biology and Hemp Research Institute of Chinese Academy of Agricultural Sciences, and the seed appraisal meeting was held on October 26. From obtaining the seed identification certificate on November 11, to selling part of the shares to Dezhan Health on November 19, to signing the equity exchange framework agreement with Xiongan Science and Technology on November 22, the capital operation efficiency of Hanma Group is very high. We contacted Professor Su Jianguang, member of the Party Committee and director of the Germplasm Resources Research Department of the Hemp Research Institute of the Chinese Academy of Agricultural Sciences. According to his introduction, the CBD content of "Zhonghanma No.1" has reached 3.19%, which is the seed with the highest CBD content that has passed the identification in China at present. After passing the identification, it still needs to enter the list of varieties of Yunnan Drug Control Commission before it can be used in a large area. The seeds supplied next year will not be much, mainly for breeding and production. He is the first breeder of "Zhonghanma No.1". The cooperation between the Hemp Research Institute of the Chinese Academy of Agricultural Sciences and the Hemp Group is commissioned research and development, and the contract will expire this year. This year, "Yunma No.7" was planted in large areas in Yunnan, with a calibrated content of 1% CBD, while the CBD content of industrial hemp seeds in North America was generally 3-5%. The higher the CBD content of industrial hemp seeds, the higher the benefit per unit planting area.From the point of view of CBD extraction, if the CBD content of industrial hemp is increased from 1% to 3%, the cost of raw materials per kilogram of extract will be reduced by 40%.The content of seeds not only directly affects the planting benefit, but also affects the overall competitiveness of China's industrial hemp industry. The prospect of developing seeds with high content of CBD is good. Two enterprises have obtained new processing licenses On November 14, Shenzhen Datong signed an agreement to acquire 51% of Yunnan Chengbang Fuji Biotechnology Co., Ltd. At present, the industrial and commercial registration has been changed. According to the announcement, Shenzhen Datong realized the indirect control of Yunnan Huayun Jinxin Biology through the acquisition of Chengbang Fuji shares, while Huayun Jinxin has obtained a new industrial hemp processing license. It is understood that the CBD annual production capacity of Huayun Jinxin Biology is 3-4 tons. At present, the comprehensive price of all kinds of CBD is 4 million US dollars and 2800 RMB per ton. If it is converted into 3 million US dollars per ton, the annual income of Huayun Jinxin's existing production capacity is about 90 million RMB, and the profit is about 45 million RMB. If production has been started or is about to start, it will produce economic benefits this year. Shenzhen Datong made it clear that Huayun Jinxin's industrial hemp project has obtained the "Yunnan Industrial Hemp Processing License" and "Yunnan Industrial Hemp Planting License", the fuel ethanol project has obtained the "Investment Project Record Certificate" of Yunnan Economic Commission, and the bio-organic fertilizer project has been approved by Binchuan County Engineering Bureau. Before March this year, enterprises can apply for planting licenses as long as they can legally obtain planting seeds, have certain human and material resources and business premises, and have downstream customers. The real economic value of industrial hemp is the deep processing stage, which requires a processing license, which has a certain threshold, and the processing license issued by the government is very few. Li Ming (a pseudonym), the head of an industrial hemp cultivation enterprise, told the Securities Daily reporter. Shenzhen Datong emphasizes that the acquisition of Chengbang Fuji's equity is to lay out business sectors such as fuel ethanol, industrial hemp and organic fertilizer, which are highly related and synergistic. After the completion of this acquisition, it will not have a significant impact on the company's operating income and net profit in 2019, and the impact on the company's long-term earnings is uncertain. This transaction does not constitute a related party transaction, nor does it constitute a major asset reorganization. On November 16, "Luxi Window" reported the opening ceremony of Kangbei Yunnan Yunxing Biology. According to the announcement of Kangbei, Yunxing Biology has obtained the industrial hemp processing license and started production. According to the public data, when Yunxing Biology applied for the processing license, it declared an annual processing capacity of 3000 tons of industrial hemp mosaic leaves, which was converted by the CBD content of "Yunma No.7", with an annual CBD output of 20 tons or more. According to the above calculation method of Huayun Jinxin, it is estimated that the annual income will be more than 400 million yuan and the profit will be more than 200 million yuan. Cloud apricot biology has started production, and this year's benefits and even profits are more certain. At the beginning of the year, many listed companies, such as Chengzhi Stock, Fangsheng Pharmaceutical, Meiyingsen and Shunhao Stock, announced the construction of industrial hemp processing plants. These factories are under construction, the fastest progress of Chengzhi shares in the acquisition of Yunnan Hanmeng Pharmaceutical, the plant structure is close to the top. The new plant has a long period. Huayun Jinxin and Yunxing Bio-energy were built and put into production in the same year, mainly based on the original alcohol or ginkgo extraction production line, and have relevant technical reserves. In the industrial hemp craze at the beginning of the year, some grass-roots public security bureaus in Yunnan issued wrong licenses because they were not familiar with their business. For example, they issued processing licenses for planting enterprises, and issued processing licenses for production in the pre-approval process. Since then, Yunnan Drug Control Bureau has strengthened its management, including on-site inspection, sample inspection and approval authority. At present, it is very difficult to obtain a processing license in Yunnan, which requires complicated procedures and strict examination and approval. Yunnan is also in the process of revising industrial hemp regulations, and after the implementation of the new regulations, it may be more difficult to obtain processing licenses. The Ministry of Agriculture and Rural Areas launched a survey on the current situation of industrial hemp industry On November 18-20, the Planting Management Department of the Ministry of Agriculture and Rural Areas formed a special research group to investigate the industrial hemp industry in Yunnan, and will also go to Heilongjiang to investigate. From the point of view of notification, the purpose of investigation is to understand the production and management status of industrial hemp industry and promote the standardized and stable development of industrial hemp industry. The industry's interpretation of this research activity is that the state has attached great importance to the industrial hemp industry, not excluding the introduction of a unified policy in the future. At present, the development of industrial hemp industry is restricted by the seed quality of the front end and the application of the back end. If the United Nations Bureau of Narcotics deletes CBD from the control table and FDA allows CBD to be added to food next year, the industrial hemp industry will usher in unprecedented opportunities for development. Whether China's industrial hemp industry can win in the global competition depends first on the competitiveness of industrial hemp seeds. In the investigation of the Ministry of Agriculture and Rural Areas, enterprises suggest that the state should liberalize the research of high-quality seeds conditionally, liberalize the restrictions on private enterprises entering seed research, and guide policies to speed up the research of high-content seeds of industrial hemp, so as to promote industrial development; At the same time, industrial hemp seeds are identified at the national level to break the restrictions on the closed use of seeds in various provinces, so that high-quality seeds can be used in a wider range. FDA in the United States and Europe have approved the marketing of CBD drugs, while China only permits the addition of "cannabis leaf extract" as a cosmetic raw material, and the relevant departments in China should liberalize the research and development of industrial cannabis CBD extract in food, health products and pharmaceuticals. In Europe and the United States, the mosaic residue extracted from industrial hemp (without THC) and extracts have been well applied in animal feed. In the investigation, some enterprises put forward that they hope that the agricultural department will allow the evaluation of the mosaic residue and extracts of industrial hemp, and list the mosaic residue of industrial hemp in the Catalogue of Feed Raw Materials. The industrial hemp extract was listed in the Catalogue of Feed Additives. If we say that the restrictions on seed research and development can be broken by Yunnan and Heilongjiang provinces on their own, the restrictions on application will be decided by the ministries and commissions of the state. Research by the Ministry of Agriculture and Rural Affairs has brought hope to the industrial cannabis industry. The prospect of industrial hemp attracts attention The layout of industrial hemp in Shenzhen Datong has begun before. On April 17 this year, Shenzhen Datong announced its intention to set up a joint venture subsidiary, which mainly invests in the integration and expansion of the whole industrial chain of industrial hemp, the research and development of CBD products and domestic and foreign sales. Shenzhen Datong said it would explore the "penetration and deep integration" of blockchain and industrial hemp business scenarios. As it involves two hot topics of block chain and industrial hemp, Shenzhen Datong received a letter of concern from Shenzhen Stock Exchange on April 18. Since then, Shenzhen Datong has carried out joint venture cooperation and acquisition in the field of industrial hemp, and signed the Strategic Cooperation Framework Agreement with the People's Government of Dongshan District, Hegang City, Heilongjiang Province. The cooperation covers the construction of industrial hemp planting base and deep processing base. Securities Daily reporter learned that industrial hemp is mainly used in some cosmetics fields in China, the main terminal consumer market is abroad, and the domestic supervision of industrial hemp is relatively strict. The ingredients of industrial hemp include CBD and THC (tetrahydrocannabinol), among which the deregulation of CBD application is still controversial in the world, while THC is recognized as a drug ingredient. This has a higher requirement for the ability of industrial hemp enterprises to guard against risks, and if the supervision is not effective, it will have an impact on social stability. Li Ming said. Li Ming said that the gross profit of industrial hemp cultivation is not high, there is a certain risk of loss in the cultivation enterprises, and the gross profit rate of industrial hemp processing is relatively high, but it is also related to the trend of international hemp prices. If the application of industrial hemp in medicine and food additives is opened up in China, industrial hemp still has great prospects. At this stage, if raw materials are put into the domestic market, supply must exceed demand, and if enterprises are involved in processing business, they must have better channels overseas. Li Ming said so. Huayun Jinxin is communicating and negotiating with overseas customers, and has contacted several overseas customers. At present, industrial hemp mosaic processing is in the stage of small batch production, the company is expanding the production scale as planned, and the cultivation of industrial hemp is also advancing as planned. In response to an interview with the Securities Daily, Shenzhen Datong insiders said that according to the agreement of the merger and acquisition agreement, if Chengbang Fuji's production is progressing smoothly, it is expected to bring profits to the company by 2020. Price difference of a thousand times from raw materials to products Planting scale is restricted by processing capacity What does industrial hemp, which is described as a trillion-level market, really look like? In mid-late October, Daily Economic News reporters rushed to many places in Yunnan to investigate and witness the harvesting and processing of industrial hemp. Reporters found that the price difference between planting and processing is huge, the price of flowers and leaves sold by farmers to the company is 10 yuan per kilogram, while the price of CBD (cannabidiol) purified in the international market is 5000 dollars per kilogram, which is thousands of times the gap. Because of the high technology and license threshold in industrial hemp processing, it is difficult for CBD crystal production capacity to be released explosively and centrally, which also means that limited CBD production capacity will restrict the scale of industrial hemp cultivation. It is worth noting that many listed companies have been heated in the capital market this year because of the disclosure of their layout in the field of industrial hemp. But there is still a question mark over how much industrial hemp will ultimately contribute to the performance of listed companies. Weather factors affect harvesting The CBD-rich flowers and leaves of industrial hemp are thin and long. The headache for growers is the uncertain weather, which will affect the harvest progress. One day in mid-October, when the drizzling rain hit the farmland, Zhang Yang (a pseudonym), an employee of Yunnan Muya Agricultural Science and Technology Co., hemp extraction centrifuge ,thin film distillation, Ltd. (Hereinafter referred to as Yunnan Muya), a subsidiary of Longjin Pharmaceutical Holdings, was not good at all. It's only been a sunny day and it's raining, so I can't harvest it. Zhang Yang shook his head and muttered to his colleague Hao Peng (a pseudonym). Hao Peng did not speak, turned around and put his hands behind him, and smiled bitterly. After inspecting the planting land, they were ready to return to the county town. There are more than 30 kilometers from here to the county seat, and about 5 kilometers are mountain roads with great curvature. Zhang Yang said that "people who are prone to carsickness usually vomit.". Zhang Yang said that the target of harvesting is this year's hot industrial hemp. At this time, Zhang Yang and Hao Peng are very anxious, because there is still a week to go before the Frost's Descent of the lunar calendar. Frost's Descent "killing hundreds of herbs", the last solar term in autumn also means the coming of winter. As a common crop, the growth cycle of industrial hemp can not avoid the law of all things, which is the golden period of the final harvest. Hao Peng and Zhang Yang were talking and laughing in the car, muttering a joke casually: "It's like God is against us." They are thinking about the emergence of seeds this spring, and the growers of industrial hemp are eager for more rain in the red soil. However, the spring drought in Yunnan lasted for a long time, which affected the sowing and emergence of industrial hemp. Industrial hemp is a high-stalk crop, which is not tolerant to soil drought, and its yield is low when there is less rain. It doesn't rain when it should rain, and it doesn't rain when it should be sunny. Farmers are most afraid of such "tricks". Fang Huarong, chairman of Ximeikang Agricultural Development Co., Ltd. (Hereinafter referred to as Ximeikang), a subsidiary of Kangbei, also faced the same trouble in Zhanyi District, Qujing City, about 200 kilometers from Muya, Yunnan Province. The seeds of industrial hemp were sown, but the seedlings did not emerge because of the drought. Fang Huarong was worried and watched the weather forecast every day, hoping for more rain. Things are not satisfactory, Fang Huarong can only plant nutrient solution for industrial hemp. This is also a helpless move, no longer "infusion", industrial hemp will not grow tall. Compared with publicity, Fang Huarong still has some small luck. At the Ximeikang industrial hemp planting base in Haojiaozi Village, Yanfang Township, the weather cleared up for a period of time. In the middle and late October, farmers began to harvest. It is the male plant of industrial hemp, commonly known as male hemp. Where there is a male, there is a female, and the female plant is "Ju". On industrial hemp plantations, male and female plants are mixed together. The male plants flower and the pollen is scattered on the female plants, which are allowed to set seeds. Male hemp stalks and flowers and leaves lie in piles on the cement floor of the courtyard dam. They are uniform and have been exposed to the sun for several days. After drying for a period of time, the light green hemp stalks gradually turn yellow, like a pile of dry wood or straw. Aunt Wang, a farmer, drove a small farm machine through the cement field and crushed the flowers and leaves on the hemp stalks. The roar of the engine, the crackling of the dead branches of industrial hemp being crushed.. After a few rounds, most of the long flower leaves like banana leaves have been crushed to pieces. Aunt Wang planed the broken flowers and leaves together with farm tools and put them into woven bags, which is the raw material for extracting CBD. It is understood that the most valuable CBD of industrial hemp is hidden in Huaye. Daily Economic News reporter inquired with many people in the industry in Yunnan, and made a comprehensive understanding of the cycle of industrial hemp cultivation. Industrial hemp was planted in mid-May, and one month later, it grew to 1 meter high. Two months later, when industrial hemp grows to more than 2 meters, it will usher in the fastest growth stage, sometimes 10 centimeters a day. Five months after planting (150 days), industrial hemp can be harvested, first male hemp and then female hemp. Flowers, leaves and flowers are used to extract CBD; hemp stalks and stems are used to make fiber clothing; hemp seeds are used as cooking oil and can also be peeled and eaten. Hao Peng casually peeled off a hemp seed and skillfully opened it with his mouth, which was not much different from eating melon seeds. The husked seeds of industrial hemp seeds are called "hemp seeds". Recently, Meiyingsen, a popular stock, cooperated with Jiangnan University to develop the main raw material of artificial meat, which is "hemp seed". On the planting base of Haojiaaozi Village, there are still a large number of female industrial hemp plants ready to be harvested. This is a green scene, female hemp high and low scattered in the field, high industrial hemp has 3 to 4 meters. When the breeze blows, the industrial hemp plantation will waft a strange fragrance, which the local people vividly describe as "hemp smell". Male hemp withers earlier than female hemp, and once the pollen of male hemp flies out, it has no value, which will also affect the CBD content of female hemp. Ximeikang's technicians explained the reason why male hemp was harvested before female hemp. Generally speaking, the CBD content of industrial hemp planted in Yunnan is between 0.8% and 1.6%. The CBD content of some industrial hemp planted by Ximeikang is 1.2%, which is already at a relatively high level. There are many factors affecting the CBD content of industrial hemp, and climate environment is one of them. In the most critical harvesting stage, the CBD content of industrial hemp also has an interesting marginal decline law. In October, the hemp seeds in the industrial hemp tidbit will be wrapped in slurry, which is the time when CBD content is the highest. Zhang Yang and Hao Peng's key inspection work during this period is to check which hemp seeds have been wrapped in slurry. Hao Peng picked the hemp seeds, peeled off the shell and flowed out milky white liquid. He found an industrial hemp with wrapped slurry. "This can be collected. If it is a little older, it will be worthless." Wait for the weather to clear up, and then do it continuously. Zhang Yang echoed that they were looking forward to a good harvest of industrial hemp this year. The size of the profit is difficult to quantify at the moment. Cannabis has always been a strictly controlled product stipulated by the United Nations Anti-Drug Convention, and it is still illegal to carry and smoke cannabis in most countries. What is banned by statute belongs to recreational hemp, and industrial hemp and it are two dimensions. THC (tetrahydrocannabinol) content of less than 0.3% is industrial hemp. Heilongjiang Province and Yunnan Province are the few provinces in China that allow the cultivation of industrial hemp. Honghe, Wenshan, Qujing, Xishuangbanna and other places are relatively concentrated industrial hemp cultivation areas. Altitude, soil, water source and climate environment are the resource endowments of industrial hemp cultivation in these areas. Yanfang Township, Zhanyi District, Qujing City, is more than 30 kilometers away from the urban area, which is close to the source of the Pearl River, a large water system in the south. At the foot of Maxiong Mountain, there is a gurgling stream, which is the place where Xu Xiake crossed three times to find the source. On the other hand, industrial hemp is not difficult to grow and is a more tolerant crop. Fang Huarong, a native of Zhejiang Province, claimed to be an old farmer who came out to work in the 1960s. He has worked in agriculture all his life, planting rice, corn, sugarcane, medicinal materials and so on, and industrial hemp has been rated as the best by him. He described growing industrial hemp as a "lazy crop." "The best crop to grow is a lazy crop!" On the roadside of Haojiaaozi Village, some "crooked neck" industrial hemp plants are upside down, and even the roots of the plants are exposed. However, they are not dead yet, and their vitality is particularly tenacious. It's half broken by hail and can still grow. Ximeikang's technicians said. Yunnan has a long history of agricultural cultivation, and flue-cured tobacco and corn are more common crops for farmers. Flue-cured tobacco has high economic benefits, but it is difficult to resist natural disasters such as hail. If half of it is interrupted like industrial hemp, it is very difficult to grow flue-cured tobacco. Ximeikang's technicians said. Corn is easy to grow, but its economic benefits are not comparable to flue-cured tobacco. With good cultivation and high economic benefits, industrial hemp is like a combination of the two, which has its own comparative advantages. Xiao Chen, a farmer somewhere in Yunnan, cooperated with Yunnan Muya to plant industrial hemp for the first time this year. He had been idle at home before and was not interested in general crop cultivation. The economic benefit is also good, the economic benefit of planting one mu of industrial hemp is 2000 yuan, and 100 mu of land is 200000 yuan. Xiao Chen calculated an economic account, the cost of planting one mu of land is 150 yuan, including fertilizer, soil film, human cost and so on. Eight workers are needed to harvest one mu of industrial hemp, and the daily wage is 80 yuan, which is the biggest cost for him to grow industrial hemp. The economic benefits of industrial hemp cultivation by farmers are related to the yield, and the amount of money earned varies from person to person, depending on the cultivation experience, technology and so on. The investment is small, the recovery is fast and the profit is large. This is the concise summary of the hemp man, but this sentence is not all. The "small investment" of industrial hemp cultivation corresponds to low risk. In fact, the risk is transferred in the contract, and the company has to accept more cost constraints. Yunnan Muya adopts the cooperation mode of "company plus farmer", in which the company provides technology and seeds, and the farmer is responsible for planting and picking. Whether it is Muya or Ximeikang in Yunnan, the cultivation of industrial hemp tends to choose this cooperation mode, and capital, labor and land can be efficiently reorganized. Only industrial hemp cultivation license can be obtained, and it is difficult for individual retail investors to meet the matching conditions. However, farmers can provide the company's scarce labor force and solve the problem of the company's planting base by transferring land. Industrial hemp cultivation cycle is 150 days, "spring planting and autumn harvest" can ensure the "fast recovery" of growers and companies. But it seems that the harvest cycle of industrial hemp can only be like this, and it is very difficult to harvest twice a year. You can't grow industrial hemp in winter. Fang Huarong's explanation is that the cultivation of industrial hemp should also respect its growth law. The size of the profit is difficult to quantify, farmers and growers have a good income, but the company does not see it that way. This is nothing more than two reasons, one is uncertain, this year is the first year of trial planting of Longjin Pharmaceutical, Kangbei and other listed companies, and has not yet completed all harvesting. Fang Huarong and Li Yahe, Secretary of Longjin Pharmaceutical, told the Daily Economic News that the market price of hemp leaves has not yet come out, so it is impossible to estimate the profits brought by the harvest of industrial hemp, and its contribution to the performance needs to be settled before it can be known. Second, it comes from traditional experience. Industrial hemp belongs to crops, and it is difficult for agricultural products to make a lot of money. As the aforementioned Ximeikang technicians lament, agriculture needs a feeling. Standing in the dimension of the whole industrial chain of industrial hemp, the value of each link can not be equal. Industrial hemp midstream processing industry is regarded as the link with the highest economic surplus. Such a set of comparative figures is more intuitive. Daily Economic News reporter found in many places in Yunnan that the price of flowers and leaves purchased directly by the company from farmers is 10 yuan per kilogram. If hidden costs such as land transfer costs and nursing costs are added, the price can be 20 yuan per kilogram. The price of purified CBD can reach $5000 per kilogram. According to the teleconference summary of the overseas team of Tianfeng Securities Research Institute in March this year, in 2017, CBD with 95% purity in Yunnan was quoted at 13000 US $/kg. From industrial hemp raw materials to finished products, the product premium is more than 1700 times. In the whole industrial hemp industry chain, the gross profit rate of the processing link is also very high. Although reporters do not have specific figures, they can compare international cannabis companies horizontally. The world's leading industrial hemp companies, such as Canopy Growth Corp and Aurora hemp, have gross margins of more than 70% in the last two years. The key to industrial hemp is processing, and there is no profit without processing. Fang Huarong pointed out the key point directly. The downstream application market of CBD can support its high quotation in the international market. The prospect is very good, and the market potential of European and American countries is huge, which is a trillion-level industry. Fang Huarong smiled, and he was very optimistic about the prospects of the downstream application market of industrial hemp. Fang Huarong's optimism is not unreasonable, before the reporter interviewed, brokerage research reports and foreign cannabis companies have made profit forecasts. According to Euromonitor International, the global legal cannabis market was about $12 billion in 2018; by 2025, the legal product market will be $166 billion. The demand for cannabinoid CBD has increased, and the growth rate is expected to be close to 80% in the next two years. Canopy Grogwth has mentioned the main application market size of industrial hemp in 2017, with a total market size of 2650 billion yuan for sports drinks, alcoholic drinks, health care and sleep. The existing CBD supply does not fully meet the downstream market application, to a certain extent, the processing link of CBD purification has a "ceiling" in production capacity, and the constraints of supply increase are greater. Taking domestic enterprises as an example, this is mainly restricted by the threshold of industrial hemp processing license and technology. Only 6 enterprises in Yunnan have CBD processing licenses. Industry insiders told reporters that this includes Hansu Biology, Baiou Biology, Yunnan Academy of Agricultural Sciences, Yunnan Hanruisi Biotechnology Co., Ltd. CBD processing qualification approval procedures are more stringent and need to be checked by the public security department. In fact, some CBD processing plants are hidden and refuse to be visited by outsiders. Yunnan Hansu Biotechnology Co., Ltd. (Hansu Biology), which is controlled by Hanma Investment Group Co., Ltd. (Hereinafter referred to as Hanma Group), is an example. From Kunming to Haikou Town, this is the expressway around Dianchi Lake. Walking straight inside the town of Haikou, you can see slogans from the last century and Soviet-style buildings. The address of the industrial and commercial information registered by Yunnan Hansu is the factory building of Xiyi Stock Company, and the innermost is its processing plant. Different from the traditional workshop of Xiyi Stock Company, Yunnan Hansu Workshop is made up of blue irregular squares. Standing outside the factory building, the reporter could still hear the roar of the machines inside. There are no interviews here. The staff guarding the gate said. Ximeikang's industrial hemp processing plant is near the office, which was originally a material reserve. At present, the industrial hemp processing plant has not yet obtained a processing license, but it has the technology to purify CBD. Fang Huarong told reporters that the technology used in Ximeikang Industrial Hemp Processing Plant is solvent extraction process. Feeding, crude extraction, refined extraction and finished crystal, the CBD extraction of industrial hemp is generally these four links. The particles of flowers and leaves are soaked in a container for about half an hour, and then filtered into a large tank (evaporation tank). Li Yongping of Ximeikang Rough Workshop took the reporter into the workshop and explained the rough steps in detail. This workshop is relatively clean, and some processes can be automated. In this workshop, the particles of flowers and leaves will become black paste sticky, and then enter the refining workshop, "the last one is white CBD crystals, just like salt.". In fact, the audit of entering Ximeikang processing plant is also very strict. First of all, vehicles entering and leaving the factory area should be strictly registered, and non-working vehicles are prohibited from driving into the factory area. Secondly, there are more than 60 cameras in the Ximeikang processing plant, and the surveillance pictures are not only seen by the monitoring room, but also networked with the public security system. We have two processing plants, and the total annual capacity of CBD crystals is 10 tons. Fang Huarong said that at present, this production capacity ranks in the forefront of industrial hemp processing plants in Yunnan Province. In this year's industrial hemp boom, there are more than 40 stocks involved in the concept. Shunhao Stock, Dongfeng Stock, Tianjin Magcard and other listed companies focus on processing links, but still rely on cooperation with licensed processing plants such as Hansu in Yunnan. Others, such as Longjin Pharmaceutical Industry, lay out the industrial chain in the planting link. It is worth mentioning that the scale of industrial hemp cultivation is also subject to the capacity of processing plants. There are 5000 mu of industrial hemp planting base in Zhanyi District, which will be expanded to 20000 mu next year. Fang Huarong said that the CBD processing capacity of their processing plant is 50000 mu of raw materials. Longjin Pharmaceutical also sells the harvested industrial hemp to processing plants. The performance of listed companies involved in the concept of industrial hemp processing may not be fully realized in the short term; the profit contribution of mosaic sales of listed companies involved in the concept of industrial hemp cultivation is not as good as expected. From the perspective of a more circuitous industrial chain, the income of farmers also depends on the demand of industrial hemp processing plants. When raw materials exceed the capacity limit of processing plants, industrial hemp mosaic leaves are no longer needed, resulting in excess supply. This year, the planting area of industrial hemp in Yunnan is about 170000 mu. Professor Yang Ming of Yunnan Academy of Agricultural Sciences said that as for whether the scale of subsequent planting will increase,thin film distillation, it depends on the scale of processing capacity. Source: Brokerage China, Daily Economic News, etc. Return to Sohu to see more Responsible Editor:. toptiontech.com

Fecha de Publicación: 26-08-22

The decarboxylation reaction,

Descripción: Original title: The decarboxylation reaction, which has been studied for more than 200 years, can become a hot spot again in this way. Previously, we introduced the recent progress in the study of photoredox-catalyzed C (sp 3) -H arylation reactions (). This kind of reaction mainly involves the formation of the corresponding carbon-centered radicals from the C (SP3) -H bond at the α-position of aliphatic compounds containing heteroatoms (N, O, S, etc.), such as aliphatic amines, ethers, thioethers, etc., by hydrogen atom transfer (HAT), followed by coupling with halogenated aromatic hydrocarbons in the presence of Ni catalyst to obtain the target products. What we are going to discuss today is also an arylation reaction, but through another way, the decarboxylation of aliphatic carboxylic acids produces radical active species, which further completes the subsequent transformation. Carboxylic acids are diverse and abundant in nature, and many of these compounds have been commercialized. Decarboxylation of these compounds as raw materials into other synthons is an effective strategy to obtain a variety of structural units. Throughout the development of organic chemistry research, decarboxylation reaction can be regarded as a classical chemical transformation. As Early as in 1849, German chemist Adolph Kolbe discovered that high-concentration CH3COONa solution could undergo decarboxylation dimerization by electrolysis to form C2H6, in which CH3COO- could be oxidized at the anode and eliminate one molecule of CO2 to form · CH3. The Kolbe electrolysis reaction was born by coupling two molecules of · CH3 to form the final product. Later, this method was extended to other higher aliphatic carboxylic acids, and even two different carboxylic acids were mixed to prepare more complex hydrocarbons. Reaction Mechanism of Kolbe Electrolysis Reaction (Image Source: Reference ) Another well-known decarboxylation reaction is the Hunsdiecker reaction. In 1861, Russian chemist A. Borodine mixed CH 3COOAg with Br 2, and a molecule of CO 2 was eliminated under heating to give the decarboxylated brominated product. Until 1942, German chemist H. Hunsdiecker further studied the reaction process, extended the substrates involved in the reaction to aliphatic carboxylic acids,winterization filtration, which were converted to the corresponding silver salts and then introduced Br 2, and then heated to obtain brominated hydrocarbons with one carbon atom reduced. This decarboxylation and bromination process is not only suitable for aliphatic carboxylic acids such as alkyl and alkenyl, but also for some aromatic carboxylic acids. Br2 can be replaced by other halogen sources such as Cl2 and I2, and even more mild halogenation reagents such as BrCCl3 and CHI3 can be used to complete the above transformation after the reaction conditions are improved. Hunsdiecker reaction (Image: Reference ) In addition, Derek Barton, a British chemist, also developed a series of reactions named after him, including Barton's radical decarboxylation reaction. The reaction starts from the aliphatic carboxylic acid and is converted into the thiohydroxamic acid ester, and then decarboxylation reduction is carried out to obtain the alkane product. To this day,wiped film distillation, many people continue to study reactions involving decarboxylation processes using carboxylic acids as raw materials, and the discussion is increasing. Barton Radical Decarboxylation (Image: Reference ) Expand the full text From the reactions mentioned above, we can find that most of the carboxylic acid substrates are decarboxylated through the free radical pathway to produce the corresponding free radical intermediates, which then participate in the subsequent chemical transformation. Photoredox catalysis has also been developed with the vigorous revival of free radical chemistry in recent years, so people will also think of using this way to design decarboxylation reactions. In this issue, we will introduce the achievements in the research of photoredox-catalyzed decarboxylation and arylation of aliphatic carboxylic acids, the protagonist of which is still Professor David W. C. MacMillan of Princeton University in the United States. In 2014, Professor David W. C. MacMillan's team used Ir 3 as a photoredox catalyst to realize the decarboxylation coupling of α-amino acids modified by N-Boc protecting groups with terephthalonitrile, and finally obtained benzylamine products. Both cyclic and acyclic α-amino acids can participate in the reaction, and the source of arylation can be replaced by other electron-withdrawing substituents (4-cyanobenzoic acid methyl ester, 4-cyanophenyl diethyl phosphite, etc.) Or even heteroaromatic nitriles. Decarboxylative coupling of N-Boc protecting group-modified α-amino acids with terephthalonitrile (Image source: Reference ) Substrate range for N-Boc protecting group-modified α-amino acids (Image source: Reference ) Range of substrates for aromatic nitriles (Image source: Reference ) The reaction involves an Ir III/Ir IV/Ir III catalytic cycle, and the decarboxylation of the alpha-amino acid is mainly completed through the following way: the alpha-amino acid 5 modified by an N-Boc protecting group is deprotonated under the action of alkali CsF, One-electron oxidation by Ir IV photoredox-catalyzed active species gives the carboxyl radical intermediate, which is then rapidly decarboxylated (eliminating one molecule of CO2) to form the α-amino radical 6. 6 is further combined with aromatic nitrile free radical anion to obtain the target product. Possible catalytic cycles for the reaction (Image: Ref. ) In the same year, they cooperated with Professor Abigail G. Doyle of Princeton University in the United States, using NiCl2 coordinated by 4,4 '-di-tert-butyl-2, decarboxylation after extraction ,50l rotovap,2' -bipyridine (dtbbpy) as a transition metal catalyst. Ir 2 (dtbbpy) PF 6 was used as a photoredox catalyst to realize the decarboxylation coupling of N-Boc protecting group-modified α-amino acids with halogenated aromatic hydrocarbons. Ni/photoredox-catalyzed decarboxylation coupling of N-Boc protecting group-modified α-amino acids with halogenated aromatic hydrocarbons (Image source: Reference ) This dual catalytic system has also been seen in previous articles (see recommended reading at the end of this article ), and in fact, the combination of Ni catalysts with photoredox catalysts to design C-C bond coupling reactions began with this work. The process of α-amino acid decarboxylation to form α-amino radical 4 is similar to the previous reaction, and 4 can be further coupled with bromine and iodobenzene through C (sp 3) -C (sp 2) bonds in the presence of Ni catalyst, thus obtaining decarboxylation arylation products. In addition, halogenated heteroaromatics can also be used as the source of arylation. Because of the low electron density of the aromatic ring of pyridine and pyrimidine, the corresponding chlorinated compounds also have good reactivity. The catalytic cycle involved in the dual catalytic system (Image source: Reference ) In 2016, Professor of David W. C. MacMillan cooperated with Professor of Gregory C. Fu of California Institute of Technology (California Institute of Technology). Chiral bisoxazoline ligand 6 modified NiCl2 was used as a transition metal catalyst. Based on the above biscatalytic system, the asymmetric decarboxylation coupling of N-Boc protected α-amino acids with bromoaromatic (hetero) hydrocarbons was designed, and chiral benzylamines were obtained with good enantioselectivity. Tetrabutylammonium iodide (TBAI) was used as an additive to increase the reaction rate. Asymmetric Decarboxylation Coupling of N-Boc Protecting Group Modified α-Amino Acids with Brominated (Hetero) Aromatic Hydrocarbons (Image Source: Reference ) In order to demonstrate the practical value of this method, they also synthesized two chiral benzylamines 7, 8, 7 and 8 from leucine modified by N-Boc protecting group, which can be used to obtain two bioactive molecules through C-C bond coupling of amide and Buchwald-Hartwig amination, respectively. Application of Asymmetric Decarboxylation Coupling to Chiral Benzylamine (Image Source: Reference ) Another work also involves the decarboxylation process, but the reaction materials are different. Professor David W. C. MacMillan also cleverly used oxalyl chloride to condense with alcohol to obtain the corresponding oxalyl monoester, which could be directly used in decarboxylation coupling reaction without purification, and could realize C (sp 3) -C (sp 2) bond coupling with bromoaromatic hydrocarbons by means of Ni/photoredox dual-catalytic system. In the meantime, oxalic acid monoester needs to eliminate two molecules of CO2 to form alkyl radicals. Decarboxylative coupling of oxalic acid monoesters with brominated aromatic hydrocarbons (Image source: Ref. ) These are the main works of photoredox-catalyzed decarboxylation and arylation of aliphatic carboxylic acids in recent years. At this point, you may ask, what is the advantage of photoredox catalytic system compared with the previous electrochemical and thermal reaction mode of decarboxylation process? The answer, of course, is that the reaction conditions are milder and the decarboxylation can proceed smoothly at room temperature, thus further expanding the scope of application of the substrate. In addition, with the development of transition metal-catalyzed reactions, the cross-coupling process is no longer limited to C-C bonds, C-N, C-O and C-X (X = Cl, Br, I) bonds and other coupling reactions have been reported, which means that in addition to the decarboxylation described in this paper, more other types of transformations can be achieved by combining photoredox catalysts with transition metal catalysts. I will continue to discuss this in subsequent articles. C (SP3) -H bond activation: another window can be opened by closing the door of the directing group Sp3-hybridized C-C bond coupling is too difficult? It is recommended that you use this method taught by MacMillan. References Jonathan D. Bell et al.,  Recent advances in visible light-activated radical coupling reactions triggered by (i) ruthenium,  (ii) iridium and (iii) organic photoredox agents. Chem. Soc. Rev. 2021, 50 , 9540. A. K. Vijh et al., Electrode Kinetic Aspects of the Kolbe Reaction. Chem. Rev. 1967, 67 , 623. Robert G. Johnson et al., The Degradation Of Carboxylic Acid Salts By Means Of Halogen - The Hunsdiecker Reaction. Chem. Rev. 1956, 56 , 219. László Kürti, Barbara Czakó. Strategic Applications of Named Reactions in Organic Synthesis : Elsevier, 2005. Derek H. R. Barton et al., The invention of new radical chain reactions. Part VIII. Radical chemistry of thiohydroxamic esters; A new method for the generation of carbon radicals from carboxylic acids. Tetrahedron 1985, 41 , 3901. Zhiwei Zuo et al.,  Decarboxylative Arylation of α-Amino Acids via Photoredox Catalysis: A One-Step Conversion of Biomass to Drug  Pharmacophore. J. Am. Chem. Soc. 2014, 136 , 5257. Zhiwei Zuo et al., Merging photoredox with nickel catalysis: Coupling of α-carboxyl sp 3 -carbons with aryl halides. Science 2014, 345 , 437. Zhiwei Zuo et al.,  Enantioselective Decarboxylative Arylation of α-Amino Acids via the Merger of Photoredox and Nickel Catalysis. J. Am. Chem. Soc. 2016, 138 , 1832. Xiaheng Zhang et al.,  Alcohols as Latent Coupling Fragments for Metallaphotoredox Catalysis: sp 3 -sp 2 Cross-Coupling of Oxalates with Aryl  Halides. J. Am. Chem. Soc. 2016,jacketed glass reactor, 138 , 13862. Return to Sohu , see more Responsible Editor: toptiontech.com

Fecha de Publicación: 26-08-22

Difference between Short-path Distillation and Molecular Distillation-Shanghai DEA

Descripción: Original Title: Difference between Short-path Distillation and Molecular Distillation-Shanghai DEA Short-path distillation, "short path" refers to a shorter distance, in a broad sense, the evaporator adopts the design scheme that the distance from the evaporation surface to the condensation surface is less than 300 MM, which can be called a short-path distiller. In terms of design structure, it can be divided into scraper short-path distiller, centrifugal short-path distiller and short-path distillers evolved from the condenser installation position of film evaporator improved by some manufacturers in recent years. At present, the most mature technology widely used is the scraper short-distance distiller, which is designed to consist of a vertical evaporation cylinder heated externally,jacketed glass reactor, a central condenser and a rotating film scraper between the distiller and the condenser. The distillation process is as follows: the material is added from the top of the evaporator, and is continuously and uniformly distributed on the heating surface by the feed liquid distributor on the rotor, and then the film scraper scrapes the feed liquid into a very thin layer of turbulent liquid film, which is pushed downward in a spiral shape. In this process,molecular distillation systems, the light components escaping from the heating surface are condensed into liquid on the built-in condenser through a very short route and almost without collision, and flow down the condenser tubes and discharged through the discharge tube at the bottom of the evaporator; the residual liquid, namely the heavy components, is collected in the circular channel under the heating area and then flows out through the discharge tube at the side. Molecular distillation, more precisely, the principle of molecular distillation, wiped film distillation ,wiped film evaporator, is different from the traditional distillation which relies on the principle of boiling point difference separation, but relies on the difference of mean free path of molecular motion of different substances to achieve separation. In the distillation process, when a liquid mixture flows along a heating plate and is heated under a certain specific pressure condition, light and heavy molecules can escape from the liquid surface and enter a gas phase, and because the free paths of the light and heavy molecules are different, the molecules of different substances have different moving distances after escaping from the liquid surface, If a condensation plate can be properly set (the distance between the evaporation area and the condensation surface is generally less than 100mm), the light molecules will be condensed and discharged when they reach the condensation plate, while the heavy molecules will be discharged along the mixed liquid when they do not reach the condensation plate. In this way, the purpose of material separation is achieved. Expand the full text Attention should be paid to "specific pressure conditions" and "evaporation surface and condensation surface distance" from the description of the distillation process. That is to say, not all raw materials can realize molecular distillation; the molecular distillation process can only be realized in a scraper type short-path distiller or a centrifugal type short-path distiller; the molecular distillation is not simply distillation in the short-distance distiller, but molecular distillation, and molecular distillation must be realized by realizing molecular-level motion and realizing a separation process at a specific pressure and a specific temperature. Therefore, it is wrong to simply confuse molecular distillation with short-path distillation, and their essence is different. Features of Shanghai DEA's scraper short-path distiller: Extremely high vacuum: The special structural design of the scraper short-path distiller allows the operating pressure to reach an extremely low operating vacuum. The vacuum of the experimental scale equipment can reach 0.001 mbar, and even the industrial scale equipment can reach 0.01-0.05 mbar. The operating temperature is much lower than the boiling point of the material: because the scraped path distillation adopts the central condensation mode, the distance between the evaporation area and the condensation surface is generally less than 50mm (the distance between the experimental device is less than 10mm), so there is only a slight pressure drop between the evaporator and the condenser, that is to say, the vacuum degree at the end of the vacuum system is almost close to the vacuum of the evaporator. The design of DEA fully meets the requirements of molecular distillation process. The heating time is short: by adopting the film forming design of the vertically rotating scraper, the residence time of the material on the heating wall is only more than ten seconds. Due to the strict distance requirement between the heating wall of short-path distillation and the condenser, the light molecules escaping from the liquid surface reach the condensing surface almost instantaneously, and the heating time of the light molecules in the vapor phase can be ignored in this process. The potential for thermal decomposition is minimized. Superior efficiency of mass transfer and heat transfer: DEA short-path distillation uses a mechanical film wiping system,cbd centrifugal extractor, which is different from the uneven film formation defects of other falling film evaporators. In the short-path evaporator, the material film thickness is uniform and the flow characteristics are excellent. Because the area of the liquid level and the heating surface is almost equal, the efficiency of mass transfer and heat transfer is superior. Return to Sohu to see more Responsible Editor:. toptiontech.com

Fecha de Publicación: 26-08-22

What are the guard column and the in-line filter for liquid chromatography? How to use it? _ Impurities

Descripción: Original title: What are the guard column and online filter of liquid chromatography? How to use it? In the previous video of ChromClass, we mentioned the protective column and online filter of liquid chromatography. At that time, some students were very confused. They look like the same thing, aren't they? What's the difference? Today we will tell you in detail. Guard post The guard column of liquid chromatography, as its name implies, is used to filter the impurities in the sample and mobile phase,cbd crystallization equipment, protect the chromatographic column and prolong the service life of the chromatographic column. It is usually installed behind the injector and at the front of the chromatographic column. There are two types of protective columns: One is the freestanding ferrule protection column. The clamping sleeve is internally provided with a column core, the column core is internally provided with a filler and can be replaced, and the column core is selected according to the type of the chromatographic column. Expand the full text The other is the integrated ferrule protection column. This is a special chromatographic column structure,rotary vacuum evaporator, the front end of the chromatographic column is integrated, and the protective column ferrule can be opened directly. This type of guard column results in a smaller dead volume, but the cost of choosing an analytical column is higher than that of a conventional analytical column. It is worth noting that the column core of the guard column has no direction when it is used for the first time, but it has a direction after the first use, and it can not be used in another direction. In-line filter The in-line filter is used to filter the impurities and solid particles in the mobile phase and to protect the liquid phase system. It is usually installed at the back end of the pump and at the front end of the autosampler. Although it is also a ferrule type, nutsche filter dryer ,rotovap distillation, its filter element is only a sieve plate, regardless of the type of chromatographic column. In actual use, because the installation position of the online filter and the filter element are only a sieve plate, it can only be used to filter impurities in the mobile phase. The guard column has the same packing as the analytical column, so it can not only filter the impurities in the mobile phase and sample, but also intercept some strong retention, strong acid and strong alkaline substances in the sample to prevent them from polluting and damaging the packing in the chromatographic column. In addition, the guard column and the in-line filter are installed to reduce the maintenance cost of the instrument. Therefore, when the system has problems such as high pressure, impurity peak, chromatographic peak tailing, or separation effect of the chromatographic column, it is recommended to directly replace the protective column or the sieve plate of the online filter. Now you know the difference between a guard post and an in-line filter! Welcome to continue to pay attention to ChromClass, and we will see you next time! Animation: Small Bath Towel Not to be reproduced without authorization, if you need to contact toot toot: maoliandudududu In terms of separation scale, what categories can liquid chromatography be divided into? What are the different types of column sizes, flow rates,wiped film evaporator, and applications? Do you know what your liquid chromatograph has in common with a flush toilet? Right, they often block ~ so often have a classmate to ask us: Liquid chromatography is blocked again, how to do? How to find out where the traffic jam is? Let's talk about what to do if the liquid chromatography is blocked in this issue of micro-Q & A of Chromatography School? Return to Sohu to see more Responsible Editor:. toptiontech.com

Fecha de Publicación: 26-08-22

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