Hammer mills are widely used due to their simple structure. It is a machine with high power consumption in the feed mill, which accounts for 2/3 of the total energy of the powder production and more than 1/3 of the total energy of the pellet production. Therefore, how to make it synergistic and energy-saving is an important research topic in feed machinery. Many people have put a lot of effort into this, deduced a lot of formulas, and did a lot of experiments. The hammer is the core working part in the pulverizer, and the feed is crushed by it. It has a great influence on the efficiency of the pulverizer, so people have also done special research on the hammer.
First, the current research situation of the pulverizer hammer What is the pulverization process of the feed in the pulverizer? The West German Academy of Science Films filmed a film for this purpose. They took a shooting speed of 7,500 frames per second and shot at 0.00001 s. From the single screen of the film, the whole process of smashing a corn in the smashing room can be clearly seen. The conclusion drawn from this film is that corn requires only a small amount of energy to break when it is subjected to a frontal impact; but when it is eccentrically impacted, it requires much more energy to break. Most of the corn kernels in the crushing chamber are eccentric shocks, which will inevitably waste a lot of energy. This is why the shredder does not use energy efficiently. That is to say, in order to improve the efficiency of the pulverizer, it is necessary to increase the frontal impact rate. The only way is to increase the thickness of the hammer.
According to Rumpf's basic research on pulverization theory and the arguments of Herfz and Kranz, Germany's Friedish deduced the formulas related to some factors affecting the ultimate stress of material fragmentation (the formula is very complicated, then omitted). According to this formula, the smaller the comprehensive radius of curvature r of the impact point during the pulverization process, the more easily the feed is broken. The r value is composed of the radius of curvature r1 of the feed pellet and the radius of curvature r2 of the hammer. The relationship is:
The radius of curvature r1 of the hammer piece can be considered to be half the thickness of the hammer piece. When the feed type has been selected, the radius of curvature r1 of the particle is a constant value. In order to increase the pulverization efficiency, the r value must be reduced. The only way is to make r2 small, that is, to use a thinner hammer. In the test of crushing corn, Richard used hammers with thicknesses of 1/16, 1/8 and 1/4 inch respectively. Under the same conditions, the conclusion was: hammer ratio of 1/16 inch thickness The 1/8 inch hammer can increase efficiency by 23%; the 1/4 inch hammer can increase efficiency by 48%.
Liu Manru, from the China Academy of Agricultural Mechanization Sciences, has also done this kind of experiment. He (she) used the hammers of 1.6, 3, 5, and 6.25mm thickness to make the crushed corn test. The result is: 1.6mm hammer ratio 6.25 The efficiency of mm is increased by 45%; the efficiency of 5mm is increased by 25%.
Both sets of experiments have proved that the hammer is thin and efficient. Thus Friedish's theory is recognized as a traditional theory and continues to this day. But this theory and the film conclusion are opposite.
People have also made many articles on shapes and materials, but they can't solve the above contradictory conclusions. Since then, people's research on hammers has not progressed much. Nowadays, the commonly used Zui is still a rectangular hammer. The professional standard and industry standard of the People's Republic of China, "Hammer-type pulverizer hammer", stipulates that the hammer type is rectangular. Yueyang Zhengda and Wuhan Huamei are both American pulverizers, and their hammers are also rectangular. The hammers imported from Switzerland by Zhuzhou Xiangda are still rectangular.
So is there any article on the hammer that can be done?
Practice is the sole criterion for testing truth. Experiments for one purpose, different methods, and the opposite are true. This only shows that both methods are one-sided. To resolve contradictions, we must first start by analyzing contradictions. What the West German film saw was the crushing of the crushed indoor corn. From the inside, the conclusion was correct. The theory of Friedish and the experiments of Richard and Liu Manru are all calculated from the number of corn kernels leaving the crushing chamber, and the conclusion is correct. If a design can be found that both increases the frontal impact rate and allows the particles that have reached the particle size requirements to emerge from the mesh as soon as possible, the two opposing conclusions can be unified, so that the performance of the crusher is very good. Great improvement. The T-pulverizer hammer I designed was designed with this in mind, which unites the two opposing conclusions.
Second, the characteristics of the T-type crusher hammer 1. Increase the end area of ​​the hammer to increase the frontal impact rate.
After the material enters the crushing chamber, due to the centrifugal action, the feed moves in a circular motion near the sieve plate and the tooth plate, so that the impact portion of the hammer is at the end of the hammer. If the entire hammer is thickened, the frontal impact rate can be increased, but the area in which the non-working part pushes the air movement is also increased, so that the air circulation speed is increased, thereby reducing the relative impact speed of the hammer to the corn and reducing the corn. Breaking efficiency. If only the area of ​​the working part is increased and the area of ​​the non-working part is reduced, the frontal impact rate is increased and the air circulation speed is reduced, thereby increasing the relative impact speed of the hammer to the corn and improving the crushing efficiency of the corn. .
2. Add a large part of the slope to reduce the incident angle of the powder to the sieve hole. The end of the standard hammer is straight, and the corn is crushed by the front of the hammer, returning almost perpendicular to the impact surface of the hammer. There are two problems with this movement of corn granules:
(1) The granules cannot escape from the hammer hitting range very quickly. Since the particle speed is much slower than the hammer speed, it will be struck again by the hammer that is quickly caught up;
(2) The incident angle of the granules to the sieve holes is large, and the granules which are much smaller than the diameter of the sieve holes may not necessarily pass through the sieve holes, and jump back to the hammer-impacted impact after it hits the edge of the sieve holes. Both of these conditions result in unnecessary extra fine powder, reducing production efficiency and wasting energy. If the impact portion has an oblique angle α, the corn is impacted against the impact surface of the hammer, so that the corn granules impacted by the hammer are reflected toward the sieve, which greatly reduces the incident angle of the corn granules to the sieve holes. This speeds up the discharge of the powder and reduces the repeated impact. This increases efficiency, reduces energy consumption, and increases the uniformity of the powder particles.
3. The number of T-type hammers installed is less than that of standard hammers. As the working area of ​​the hammer is increased, the installed capacity is reduced, and the weight of the pulverizer rotor is also reduced, thereby reducing the internal energy consumption of the pulverizer.
Third, the T-type pulverizer hammer synergy energy-saving effect T-type pulverizer hammer test on a variety of hammer-type pulverizer can achieve significant synergistic energy-saving effect, the existing hammer-type pulverizer in addition to the spacer length Other structures can be changed without change. If the pulverizer rotor is redesigned using the T-type pulverizer hammer, the rotor can be further reduced, and the internal energy consumption of the pulverizer can be further reduced, thereby further increasing energy efficiency.
1. Comparison test (test) test data 2. Economic benefits From the data in the above table, it is easy to see that the T-type hammer is 11.4% to 15.4% higher than the standard hammer mass productivity; the pure working hour productivity is increased by 12.3% to 18.3. %, the number of hammers is reduced by 1/2 to 3/4. Take the SFSP112×30 type pulverizer as an example. According to a hammer piece, the corn can be crushed by 450t, and the electricity price is calculated by 0.7 yuan per degree. The monthly standard T-hammer standard hammer can save 440 yuan of electricity and save 13.9h of working hours. The benefits are particularly significant.
IV. Conclusion Through the above comparative experiments, the conclusions are as follows:
1.T-type crusher hammer, divided into two parts: hammer head and hammer body. The hammer is the part of the impact material. Its size varies with the size of the shredder and has a good value.
2. The impact surface of the hammer has an angle α with the longitudinal axis of the hammer. When α=0, the product size is fine, but it cannot increase energy efficiency. When the alpha value is within the range of zui, it not only increases energy efficiency, but also improves particle size uniformity.
3. The number of hammers installed in the T-type pulverizer is only 1/2 to 1/4 of the original quantity, and the weight of the rotor is reduced, which reduces the internal energy consumption of the pulverizer.
First, the current research situation of the pulverizer hammer What is the pulverization process of the feed in the pulverizer? The West German Academy of Science Films filmed a film for this purpose. They took a shooting speed of 7,500 frames per second and shot at 0.00001 s. From the single screen of the film, the whole process of smashing a corn in the smashing room can be clearly seen. The conclusion drawn from this film is that corn requires only a small amount of energy to break when it is subjected to a frontal impact; but when it is eccentrically impacted, it requires much more energy to break. Most of the corn kernels in the crushing chamber are eccentric shocks, which will inevitably waste a lot of energy. This is why the shredder does not use energy efficiently. That is to say, in order to improve the efficiency of the pulverizer, it is necessary to increase the frontal impact rate. The only way is to increase the thickness of the hammer.
According to Rumpf's basic research on pulverization theory and the arguments of Herfz and Kranz, Germany's Friedish deduced the formulas related to some factors affecting the ultimate stress of material fragmentation (the formula is very complicated, then omitted). According to this formula, the smaller the comprehensive radius of curvature r of the impact point during the pulverization process, the more easily the feed is broken. The r value is composed of the radius of curvature r1 of the feed pellet and the radius of curvature r2 of the hammer. The relationship is:
The radius of curvature r1 of the hammer piece can be considered to be half the thickness of the hammer piece. When the feed type has been selected, the radius of curvature r1 of the particle is a constant value. In order to increase the pulverization efficiency, the r value must be reduced. The only way is to make r2 small, that is, to use a thinner hammer. In the test of crushing corn, Richard used hammers with thicknesses of 1/16, 1/8 and 1/4 inch respectively. Under the same conditions, the conclusion was: hammer ratio of 1/16 inch thickness The 1/8 inch hammer can increase efficiency by 23%; the 1/4 inch hammer can increase efficiency by 48%.
Liu Manru, from the China Academy of Agricultural Mechanization Sciences, has also done this kind of experiment. He (she) used the hammers of 1.6, 3, 5, and 6.25mm thickness to make the crushed corn test. The result is: 1.6mm hammer ratio 6.25 The efficiency of mm is increased by 45%; the efficiency of 5mm is increased by 25%.
Both sets of experiments have proved that the hammer is thin and efficient. Thus Friedish's theory is recognized as a traditional theory and continues to this day. But this theory and the film conclusion are opposite.
People have also made many articles on shapes and materials, but they can't solve the above contradictory conclusions. Since then, people's research on hammers has not progressed much. Nowadays, the commonly used Zui is still a rectangular hammer. The professional standard and industry standard of the People's Republic of China, "Hammer-type pulverizer hammer", stipulates that the hammer type is rectangular. Yueyang Zhengda and Wuhan Huamei are both American pulverizers, and their hammers are also rectangular. The hammers imported from Switzerland by Zhuzhou Xiangda are still rectangular.
So is there any article on the hammer that can be done?
Practice is the sole criterion for testing truth. Experiments for one purpose, different methods, and the opposite are true. This only shows that both methods are one-sided. To resolve contradictions, we must first start by analyzing contradictions. What the West German film saw was the crushing of the crushed indoor corn. From the inside, the conclusion was correct. The theory of Friedish and the experiments of Richard and Liu Manru are all calculated from the number of corn kernels leaving the crushing chamber, and the conclusion is correct. If a design can be found that both increases the frontal impact rate and allows the particles that have reached the particle size requirements to emerge from the mesh as soon as possible, the two opposing conclusions can be unified, so that the performance of the crusher is very good. Great improvement. The T-pulverizer hammer I designed was designed with this in mind, which unites the two opposing conclusions.
Second, the characteristics of the T-type crusher hammer 1. Increase the end area of ​​the hammer to increase the frontal impact rate.
After the material enters the crushing chamber, due to the centrifugal action, the feed moves in a circular motion near the sieve plate and the tooth plate, so that the impact portion of the hammer is at the end of the hammer. If the entire hammer is thickened, the frontal impact rate can be increased, but the area in which the non-working part pushes the air movement is also increased, so that the air circulation speed is increased, thereby reducing the relative impact speed of the hammer to the corn and reducing the corn. Breaking efficiency. If only the area of ​​the working part is increased and the area of ​​the non-working part is reduced, the frontal impact rate is increased and the air circulation speed is reduced, thereby increasing the relative impact speed of the hammer to the corn and improving the crushing efficiency of the corn. .
2. Add a large part of the slope to reduce the incident angle of the powder to the sieve hole. The end of the standard hammer is straight, and the corn is crushed by the front of the hammer, returning almost perpendicular to the impact surface of the hammer. There are two problems with this movement of corn granules:
(1) The granules cannot escape from the hammer hitting range very quickly. Since the particle speed is much slower than the hammer speed, it will be struck again by the hammer that is quickly caught up;
(2) The incident angle of the granules to the sieve holes is large, and the granules which are much smaller than the diameter of the sieve holes may not necessarily pass through the sieve holes, and jump back to the hammer-impacted impact after it hits the edge of the sieve holes. Both of these conditions result in unnecessary extra fine powder, reducing production efficiency and wasting energy. If the impact portion has an oblique angle α, the corn is impacted against the impact surface of the hammer, so that the corn granules impacted by the hammer are reflected toward the sieve, which greatly reduces the incident angle of the corn granules to the sieve holes. This speeds up the discharge of the powder and reduces the repeated impact. This increases efficiency, reduces energy consumption, and increases the uniformity of the powder particles.
3. The number of T-type hammers installed is less than that of standard hammers. As the working area of ​​the hammer is increased, the installed capacity is reduced, and the weight of the pulverizer rotor is also reduced, thereby reducing the internal energy consumption of the pulverizer.
Third, the T-type pulverizer hammer synergy energy-saving effect T-type pulverizer hammer test on a variety of hammer-type pulverizer can achieve significant synergistic energy-saving effect, the existing hammer-type pulverizer in addition to the spacer length Other structures can be changed without change. If the pulverizer rotor is redesigned using the T-type pulverizer hammer, the rotor can be further reduced, and the internal energy consumption of the pulverizer can be further reduced, thereby further increasing energy efficiency.
1. Comparison test (test) test data 2. Economic benefits From the data in the above table, it is easy to see that the T-type hammer is 11.4% to 15.4% higher than the standard hammer mass productivity; the pure working hour productivity is increased by 12.3% to 18.3. %, the number of hammers is reduced by 1/2 to 3/4. Take the SFSP112×30 type pulverizer as an example. According to a hammer piece, the corn can be crushed by 450t, and the electricity price is calculated by 0.7 yuan per degree. The monthly standard T-hammer standard hammer can save 440 yuan of electricity and save 13.9h of working hours. The benefits are particularly significant.
IV. Conclusion Through the above comparative experiments, the conclusions are as follows:
1.T-type crusher hammer, divided into two parts: hammer head and hammer body. The hammer is the part of the impact material. Its size varies with the size of the shredder and has a good value.
2. The impact surface of the hammer has an angle α with the longitudinal axis of the hammer. When α=0, the product size is fine, but it cannot increase energy efficiency. When the alpha value is within the range of zui, it not only increases energy efficiency, but also improves particle size uniformity.
3. The number of hammers installed in the T-type pulverizer is only 1/2 to 1/4 of the original quantity, and the weight of the rotor is reduced, which reduces the internal energy consumption of the pulverizer.
Obstetric Delivery Table is suitable for gynecological diagnosis and examination, child-birth, caesarean operation and other gynecological surgical operations. Its height adjustment, back section and sitting section adjustment are precisely and smoothly controlled by pus rod. The low voltage system ensures user`s safety. The table has an aesthetically beautiful bodyline and the bed mattress is soft and made of leatheroid, which makes them easy to be taken off, cleaned and sterilized.
Obstetric Delivery Table,Gynecology Delivery Table,Delivery Table,Operating Table For Delivery
Shandong Lewin Medical Equipment Co., Ltd. , https://www.lewinmed.com