BTC Metcalfe law
Publish: 2021-05-05 09:31:38
1.
Nanjing HALS Medical Technology Co., Ltd. is a limited liability company (invested or controlled by natural person) registered in Jiangning District, Nanjing City, Jiangsu Province on March 23, 2010. Its registered address is located at No. 9, qingshuiting West Road, Jiangning Development Zone, Nanjing city
the unified social credit code / registration number of Nanjing HALS Medical Technology Co., Ltd. is 913201045520625259, which is Chen Zhong, the legal person of the enterprise. At present, the enterprise is in business
the business scope of Nanjing HALS Medical Technology Co., Ltd. is sales of medical devices (according to the scope listed in the license); Prepackaged food and bulk food, dairy procts (including infant formula milk powder) wholesale and retail. Sales of computer software and hardware, ship accessories, class I medical devices, general merchandise, electronic procts, cosmetics and daily chemicals; Bioengineering technology development, technology consultation, technology service and technology transfer; Health food sales General items: Sales of bio based materials (except for the items that need to be approved according to law, they can independently carry out business activities according to law with business license). In Jiangsu Province, the total registered capital of companies with similar business scope is 43631.49 million yuan, and the main capital is concentrated in 1-10 million and 10-50 million enterprises, a total of 12030
Nanjing HALS Medical Technology Co., Ltd. has invested 0 companies and 1 branch
check more information of Nanjing HALS Medical Technology Co., Ltd
2. There are three reasons for the vibration of slag vertical mill:
1. The influence of the change of material properties on the vibration
1. The particle size of the material
the material layer formed in the proction process of slag vertical mill has a certain particle gradation, so it has a certain range of requirements for the particle size of raw materials. Too large or too small particles will lead to the destruction of the grading balance, It is very harmful to weaken the toughness and rigidity of the material layer
(1) when the particle size is too large, the success rate of one-time grinding will decrease, and the number of material circulation will increase, resulting in the obvious weakening of the "medium particle size" material which does not meet the fineness requirements above the air ring. This situation also affects the smooth passing of particles meeting the requirements of fineness, leading to a vicious circle. At the same time, with the increase of the amount of recycled powder, the proportion of powdery materials on the material layer increases, the original grading balance is broken, the stability of the material layer becomes poor, and the vibration will increase. This kind of situation is common before and after the replacement of limestone. Because there are too many large particles at the head and tail of the pile, the vertical mill system will change. In operation, proper material rection can be carried out to stabilize the pressure difference and material layer
(2) when the material particles are too small, or even too much powdery material, e to the poor adhesion and good fluidity of fine particles, it is not easy to form an effective material layer, and the grinding roller is not easy to effectively "gnaw" the material for normal rolling, which is easy to cause the relative sliding between the grinding roller and the grinding plate, leading to severe vibration of the vertical mill. The existence of a large number of powdery materials will increase the st concentration, the pressure difference and the ventilation resistance, which will destroy the normal operation track of the air flow and weaken the lifting capacity of the gas. If the material is not reced in time and the necessary adjustment is made, the vibration of the vertical mill will stop soon. In serious cases, the roller will vibrate violently as soon as it is lowered. If a large amount of powdery materials are suddenly put into the mill, the vertical mill will stop suddenly, and there is no adjustment time, so this situation is difficult to control. When it is found that the material is too fine, especially when the pressure difference has increased significantly, it is necessary to rece the material in time, rece the grinding pressure, rece the outlet humidity, increase the amount of water spray, and appropriately rece the speed of the powder separator. During operation, the center is to ensure the stability of the material layer and the stability of the pressure difference. When there is a certain material layer, graally increase the grinding pressure
(3) when there are large pieces of materials in the uniform particles, the roller will also fluctuate
2. Grindability of materials
in fact, the grindability of materials has been taken into account in the selection and design of vertical mill. Generally, when the grindability and corrosiveness of materials are poor, the capacity of vertical mill will be reced and it can only be forced to run with reced materials, otherwise it will cause vibration of vertical mill and cause unstable operation. Therefore, the change of material grindability is a very important index for the operation and assessment of vertical mill
in general, the grindability of materials should be tested regularly to provide a certain basis for the operation of vertical mill and the procurement and mining of material supply department
the change of material properties has far more influence on the wear than that. The change of material properties will cause excessive wear of the lining plate, accelerate the wear progress of the lining plate, and increase the grinding pressure to ensure the output, which will cause greater impact and damage to the lining plate; The excessive wear of the liner will cause the vibration of the mill in turn, so the material supply department should consider the influence of the opposite mill when changing the material properties. Cost control should be considered comprehensively
Second, the influence of equipment failure on vibration
1. New lining plate
because the new vertical mill roller and grinding plate lining plate are relatively flat, it is not easy to stabilize and "absorb" the material, which will lead to certain vibration. In operation, the thickness of material layer can be appropriately increased, the water spray can be increased, and the material retaining ring can be increased. After a period of operation, the liner surface will graally adapt to the nature of the material and run smoothly
2. Excessive wear of the lining plate
e to the centrifugal force of the grinding plate, the large materials on the grinding plate are concentrated in the outer area of the grinding plate, so that the wear of the outer side of the grinding roller and the lining plate of the grinding plate is greater than that of the inner side ring the operation. When the material layer fluctuates greatly or the material layer is thin, this kind of unbalanced wear may cause hard impact on the inner side of the roller liner and the inner side of the disc liner, resulting in vibration. When the grinding roller liner is turned around, it may also cause this kind of vibration because the worn parts can not be completely matched
3. Damage of button bar and "tendon"
the function of the button bar and the "cattle bar" is to prevent the radial displacement of the grinding roller on the grinding plate. When they are damaged, the radial swing of the grinding roller will be too large, and the normal "suction" angle will be damaged. In serious cases, the relative sliding between the grinding roller and the grinding plate will be caused, resulting in vibration. At the same time, e to their damage, the eccentricity of the center tripod may be caused, which aggravates the vibration described in 2 above
4. The hydraulic system is faulty
the hydraulic system is one of the most important equipment systems in the vertical mill, and the huge grinding force exerted by the grinding roller on the material is provided by it. However, e to the hydraulic system failure caused by the action of the tension rod is not consistent, down roll and up roll when the three rolls are not synchronized, etc. may cause mill vibration
5. The valve of powder return hammer is faulty
when the seal of the heavy hammer valve is not tight e to excessive wear or mechanical failure, a part of the air will leak out from the vertical hammer valve, which will rece the air volume of upward feeding and affect the normal lifting of materials; On the other hand, the wind leaking into the vertical hammer valve will make the air flow in the separator disordered and make a large number of powdery materials accumulate in the cone bucket. Once the accumulated materials suddenly fall, it must be a large number of powdery materials. These powdery materials will inevitably cause large vibration when they fall on the grinding plate, and the vibration is relatively regular
6. The accumulator pressure is insufficient or the nitrogen bag is damaged
the pre charged gas pressure of nitrogen air bag in the accumulator should be 60% - 70% of the normal grinding pressure. When the accumulator pressure is insufficient or the nitrogen air bag is damaged, it will lose the buffering effect and cause the hard drop of grinding roller, which is easy to cause large vibration
7. Water spray system
the water spraying system plays an important role in stabilizing the material layer, especially when there are many powdery materials. In general, no matter how much material is fed, the sprinkler will be started to increase the toughness and rigidity of the material. When one of the three spray pipes is blocked or leaking, it will lead to the imbalance of the material layer, cause the fluctuation of the grinding roller, and cause the vibration. In addition, if the water spray system stops ring operation, the material layer in the mill will lose its toughness and rigidity, resulting in vibration of the mill
8. Retaining ring
when the material properties and the working parameters of the vertical mill are stable, the height of the retaining ring basically determines the maximum thickness of the material layer. When the retaining ring is too low, the cushion layer will become thinner, the buffer effect will be weakened, and the vibration will be intensified
9. The wear of the scraper, the uneven wear of the guide vane and the uneven damage of the wind deflector can cause the uneven distribution of the air flow in the grinding ring and in the grinding, resulting in the different thickness of the material on the grinding plate and the corresponding vibration< Third, the influence of system problems and process parameters on vibration
1
because of its hard texture, when the grinding roller grinds it, the impact and damage to the lining plate are relatively serious. At the same time, the grinding roll will also have a large jump, causing sudden vibration. Although the material into the mill has passed through several iron removal devices, the falling off protective device in the mill and the large block of lining plate will still cause large vibration
2. The belt scale is broken, out of control and fluctuates greatly
e to the change of seasons and materials, the belt scale will break and jam, especially when the limestone and sandstone are broken, the material layer will suddenly become thinner, the buffering effect will be weakened, and the grinding pressure is still large, which will cause vibration
when the belt weigher is out of control and running fast, the amount of grinding materials increases abnormally, resulting in too thick material layer and reced grinding effect. At the same time, e to the large amount of materials, the pressure difference becomes larger, and the ventilation is not smooth, when it reaches a certain limit, the vertical mill will suddenly vibrate greatly. When the feed fluctuation is large, it will cause the wave form of the feed layer, and the roller will fluctuate on the grinding plate, causing vibration
3. Sudden change of air volume and air pressure
when the SP furnace is put in and out, and the kiln is fed, stopped and collapsed, the air flow and pressure of the system will fluctuate greatly, which will change the normal movement track of the air flow in the mill, destroy the established system balance and cause vibration
4. The material layer is too thin or too thick
the material layer is actually a cushion between the grinding roller and the grinding plate. Under normal circumstances, the extrusion of the material by the grinding roller and the grinding plate is the extrusion of the material in the material layer. When the material layer is too thin, its buffering effect will be weakened and the vibration will be increased. When the material layer is too thick, the buffer effect is too large, which leads to the decline of grinding capacity and proction capacity, and the pressure difference will graally rise. When it reaches a certain limit, the vibration will suddenly increase. Therefore, in normal operation, we should closely monitor the material layer thickness and timely adjust the parameters to make the material layer stable in a certain range
5. The temperature in the mill is too high
the high temperature in the mill will lead to the destruction of the toughness and rigidity of the material layer, especially when the temperature is too high, the material becomes very loose, not only the material layer becomes thinner, but also it is not easy to be "sucked" by the grinding roller for rolling, causing severe vibration. In general, the corresponding control can be carried out by adjusting the mill baffle and the amount of water spray
6. The air volume, material volume and grinding pressure of the system do not match
in the vertical mill system, the air volume, feed volume and grinding pressure should be a balanced whole. One parameter should be changed ring normal operation, and other parameters should be adjusted accordingly. If the parameters do not match, vibration will also occur
for example, when the air volume of the system is too low, too much slag will spit out, and the gas can not blow the medium particles back to the grinding plate for grinding again, resulting in too thin material layer; At the same time, too small air volume can not lift the material smoothly, but suspended in the grinding tire, increasing the resistance of ventilation. The vicious circle will soon lead to large vibration.
1. The influence of the change of material properties on the vibration
1. The particle size of the material
the material layer formed in the proction process of slag vertical mill has a certain particle gradation, so it has a certain range of requirements for the particle size of raw materials. Too large or too small particles will lead to the destruction of the grading balance, It is very harmful to weaken the toughness and rigidity of the material layer
(1) when the particle size is too large, the success rate of one-time grinding will decrease, and the number of material circulation will increase, resulting in the obvious weakening of the "medium particle size" material which does not meet the fineness requirements above the air ring. This situation also affects the smooth passing of particles meeting the requirements of fineness, leading to a vicious circle. At the same time, with the increase of the amount of recycled powder, the proportion of powdery materials on the material layer increases, the original grading balance is broken, the stability of the material layer becomes poor, and the vibration will increase. This kind of situation is common before and after the replacement of limestone. Because there are too many large particles at the head and tail of the pile, the vertical mill system will change. In operation, proper material rection can be carried out to stabilize the pressure difference and material layer
(2) when the material particles are too small, or even too much powdery material, e to the poor adhesion and good fluidity of fine particles, it is not easy to form an effective material layer, and the grinding roller is not easy to effectively "gnaw" the material for normal rolling, which is easy to cause the relative sliding between the grinding roller and the grinding plate, leading to severe vibration of the vertical mill. The existence of a large number of powdery materials will increase the st concentration, the pressure difference and the ventilation resistance, which will destroy the normal operation track of the air flow and weaken the lifting capacity of the gas. If the material is not reced in time and the necessary adjustment is made, the vibration of the vertical mill will stop soon. In serious cases, the roller will vibrate violently as soon as it is lowered. If a large amount of powdery materials are suddenly put into the mill, the vertical mill will stop suddenly, and there is no adjustment time, so this situation is difficult to control. When it is found that the material is too fine, especially when the pressure difference has increased significantly, it is necessary to rece the material in time, rece the grinding pressure, rece the outlet humidity, increase the amount of water spray, and appropriately rece the speed of the powder separator. During operation, the center is to ensure the stability of the material layer and the stability of the pressure difference. When there is a certain material layer, graally increase the grinding pressure
(3) when there are large pieces of materials in the uniform particles, the roller will also fluctuate
2. Grindability of materials
in fact, the grindability of materials has been taken into account in the selection and design of vertical mill. Generally, when the grindability and corrosiveness of materials are poor, the capacity of vertical mill will be reced and it can only be forced to run with reced materials, otherwise it will cause vibration of vertical mill and cause unstable operation. Therefore, the change of material grindability is a very important index for the operation and assessment of vertical mill
in general, the grindability of materials should be tested regularly to provide a certain basis for the operation of vertical mill and the procurement and mining of material supply department
the change of material properties has far more influence on the wear than that. The change of material properties will cause excessive wear of the lining plate, accelerate the wear progress of the lining plate, and increase the grinding pressure to ensure the output, which will cause greater impact and damage to the lining plate; The excessive wear of the liner will cause the vibration of the mill in turn, so the material supply department should consider the influence of the opposite mill when changing the material properties. Cost control should be considered comprehensively
Second, the influence of equipment failure on vibration
1. New lining plate
because the new vertical mill roller and grinding plate lining plate are relatively flat, it is not easy to stabilize and "absorb" the material, which will lead to certain vibration. In operation, the thickness of material layer can be appropriately increased, the water spray can be increased, and the material retaining ring can be increased. After a period of operation, the liner surface will graally adapt to the nature of the material and run smoothly
2. Excessive wear of the lining plate
e to the centrifugal force of the grinding plate, the large materials on the grinding plate are concentrated in the outer area of the grinding plate, so that the wear of the outer side of the grinding roller and the lining plate of the grinding plate is greater than that of the inner side ring the operation. When the material layer fluctuates greatly or the material layer is thin, this kind of unbalanced wear may cause hard impact on the inner side of the roller liner and the inner side of the disc liner, resulting in vibration. When the grinding roller liner is turned around, it may also cause this kind of vibration because the worn parts can not be completely matched
3. Damage of button bar and "tendon"
the function of the button bar and the "cattle bar" is to prevent the radial displacement of the grinding roller on the grinding plate. When they are damaged, the radial swing of the grinding roller will be too large, and the normal "suction" angle will be damaged. In serious cases, the relative sliding between the grinding roller and the grinding plate will be caused, resulting in vibration. At the same time, e to their damage, the eccentricity of the center tripod may be caused, which aggravates the vibration described in 2 above
4. The hydraulic system is faulty
the hydraulic system is one of the most important equipment systems in the vertical mill, and the huge grinding force exerted by the grinding roller on the material is provided by it. However, e to the hydraulic system failure caused by the action of the tension rod is not consistent, down roll and up roll when the three rolls are not synchronized, etc. may cause mill vibration
5. The valve of powder return hammer is faulty
when the seal of the heavy hammer valve is not tight e to excessive wear or mechanical failure, a part of the air will leak out from the vertical hammer valve, which will rece the air volume of upward feeding and affect the normal lifting of materials; On the other hand, the wind leaking into the vertical hammer valve will make the air flow in the separator disordered and make a large number of powdery materials accumulate in the cone bucket. Once the accumulated materials suddenly fall, it must be a large number of powdery materials. These powdery materials will inevitably cause large vibration when they fall on the grinding plate, and the vibration is relatively regular
6. The accumulator pressure is insufficient or the nitrogen bag is damaged
the pre charged gas pressure of nitrogen air bag in the accumulator should be 60% - 70% of the normal grinding pressure. When the accumulator pressure is insufficient or the nitrogen air bag is damaged, it will lose the buffering effect and cause the hard drop of grinding roller, which is easy to cause large vibration
7. Water spray system
the water spraying system plays an important role in stabilizing the material layer, especially when there are many powdery materials. In general, no matter how much material is fed, the sprinkler will be started to increase the toughness and rigidity of the material. When one of the three spray pipes is blocked or leaking, it will lead to the imbalance of the material layer, cause the fluctuation of the grinding roller, and cause the vibration. In addition, if the water spray system stops ring operation, the material layer in the mill will lose its toughness and rigidity, resulting in vibration of the mill
8. Retaining ring
when the material properties and the working parameters of the vertical mill are stable, the height of the retaining ring basically determines the maximum thickness of the material layer. When the retaining ring is too low, the cushion layer will become thinner, the buffer effect will be weakened, and the vibration will be intensified
9. The wear of the scraper, the uneven wear of the guide vane and the uneven damage of the wind deflector can cause the uneven distribution of the air flow in the grinding ring and in the grinding, resulting in the different thickness of the material on the grinding plate and the corresponding vibration< Third, the influence of system problems and process parameters on vibration
1
because of its hard texture, when the grinding roller grinds it, the impact and damage to the lining plate are relatively serious. At the same time, the grinding roll will also have a large jump, causing sudden vibration. Although the material into the mill has passed through several iron removal devices, the falling off protective device in the mill and the large block of lining plate will still cause large vibration
2. The belt scale is broken, out of control and fluctuates greatly
e to the change of seasons and materials, the belt scale will break and jam, especially when the limestone and sandstone are broken, the material layer will suddenly become thinner, the buffering effect will be weakened, and the grinding pressure is still large, which will cause vibration
when the belt weigher is out of control and running fast, the amount of grinding materials increases abnormally, resulting in too thick material layer and reced grinding effect. At the same time, e to the large amount of materials, the pressure difference becomes larger, and the ventilation is not smooth, when it reaches a certain limit, the vertical mill will suddenly vibrate greatly. When the feed fluctuation is large, it will cause the wave form of the feed layer, and the roller will fluctuate on the grinding plate, causing vibration
3. Sudden change of air volume and air pressure
when the SP furnace is put in and out, and the kiln is fed, stopped and collapsed, the air flow and pressure of the system will fluctuate greatly, which will change the normal movement track of the air flow in the mill, destroy the established system balance and cause vibration
4. The material layer is too thin or too thick
the material layer is actually a cushion between the grinding roller and the grinding plate. Under normal circumstances, the extrusion of the material by the grinding roller and the grinding plate is the extrusion of the material in the material layer. When the material layer is too thin, its buffering effect will be weakened and the vibration will be increased. When the material layer is too thick, the buffer effect is too large, which leads to the decline of grinding capacity and proction capacity, and the pressure difference will graally rise. When it reaches a certain limit, the vibration will suddenly increase. Therefore, in normal operation, we should closely monitor the material layer thickness and timely adjust the parameters to make the material layer stable in a certain range
5. The temperature in the mill is too high
the high temperature in the mill will lead to the destruction of the toughness and rigidity of the material layer, especially when the temperature is too high, the material becomes very loose, not only the material layer becomes thinner, but also it is not easy to be "sucked" by the grinding roller for rolling, causing severe vibration. In general, the corresponding control can be carried out by adjusting the mill baffle and the amount of water spray
6. The air volume, material volume and grinding pressure of the system do not match
in the vertical mill system, the air volume, feed volume and grinding pressure should be a balanced whole. One parameter should be changed ring normal operation, and other parameters should be adjusted accordingly. If the parameters do not match, vibration will also occur
for example, when the air volume of the system is too low, too much slag will spit out, and the gas can not blow the medium particles back to the grinding plate for grinding again, resulting in too thin material layer; At the same time, too small air volume can not lift the material smoothly, but suspended in the grinding tire, increasing the resistance of ventilation. The vicious circle will soon lead to large vibration.
3. Dry ball mill is the material from the feeding device through the feeding hollow shaft screw evenly into the first bin of the mill, the bin has a ladder liner or corrugated liner, with different specifications of steel balls, the cylinder rotation proces centrifugal force, the steel ball will fall to a certain height, resulting in heavy impact and grinding effect on the material. After rough grinding in the first bin, the material enters the second bin through a single-layer partition board. The bin is inlaid with a flat lining board and steel balls to further grind the material. The powder is discharged through the discharging grate plate to complete the grinding operation. Grinding mass fraction refers to the mass fraction of pulp in ball mill. Grinding fineness refers to the content of specified grade in the discharge of ball mill. Grinding mass fraction and grinding fineness are interrelated and influenced each other. In the proction operation, it is mainly controlled by the regulation of grinding feed water (after water). In open circuit grinding of dry ball mill, the factors that affect the grinding mass fraction are the properties of raw ore (mainly particle size composition), ore feeding amount and ore feeding water. In addition to the particle size composition of raw ore, the grinding mass fraction and ball adding system also affect the grinding fineness. When the property of raw ore changes, if the coarse particle increases and the ore feed remains unchanged, the back water should be reced and the grinding mass fraction should be increased to ensure the grinding fineness. If the fine particle increases, the back water should be increased and the ore feed should be increased appropriately to rece the over crushing. Under the condition of keeping the ore properties and medium conditions unchanged, the grinding fineness generally increases with the increase of grinding mass fraction within a certain range, and vice versa. In a word, the grinding mass fraction can be adjusted by adjusting the feed water quantity, and then the grinding fineness can be controlled. When the dry ball mill is closed-circuit grinding, the situation becomes more complex, adding a factor of sand return. When the feed water is constant, the increase of raw feed and return sand will increase the grinding mass fraction, otherwise it will decrease. The grinding fineness is affected not only by the amount of return sand, but also by the classification efficiency. When the amount of return sand is large, the particle size composition of the whole feed is changed, the fine particle size is increased, and the grinding speed is fast. Therefore, the grinding mass fraction should be appropriately reced, and the discharge speed should be increased to rece the over crushing. When the amount of return sand is reced and the raw ore is coarse, it is necessary to rece the back water to improve the grinding mass fraction. If you are a customer of ball mill, or you have any problems in the use of ball mill, we will provide you with professional solutions for ball mill application free of charge! Call now to learn more. I believe the communication with "Xinxing" people will be helpful to your choice! You can also visit our website: www.gyxxjx.com Gongyi Xinxing Machinery Factory
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