Measures to improve the efficiency of feed mill vibrating screen

LIMA Fish Feed Machine,Chicken Feed Machine

The vibrating screen is to make the material sieved, layered, transdermally, and transport material, and to the material screening machine, the main function is to grade the material, demeral, according to quality or particle size. Separation is an indispensable auxiliary production equipment for feed production. Common vibrating screen types are: elliptic vibrating screen, circular vibrating screen, linear vibrating screen, etc., wherein linear vibration sieve is widely used in feed industries, such as raw materials such as corn, soybeans, etc. Stone, excess gray, screening; granulated screening grading, etc. The linear vibrating screen is to rotate in reverse rotation by two vibrating motors, which causes reverse excitation force to force the cabinet to make the screen for longitudinal, straight round-trip movement, and the material is continuously obliquely moving on the screen surface. The material is loose when the material is throwing, and the small particles are mixed when colliding with the screen, thereby achieving the grading and delivery of materials. The screening effect of the vibrating screen is not only a great impact on product value, but also directly affects the efficiency of the next job. Therefore, it is important to find measures to improve the efficiency of vibrating screening, and find important practical significance. 1 Factors affecting the efficiency of the vibrating screen, the screening effect of the vibrating screen is related to many factors, including material properties, screen surface structural parameters, vibrating screen motion parameters, and the like. 1.1 Material Characteristics The vibrating screen often occurs in the production process, that is, the screen is stacked, the effective sieving area is small, the process efficiency is lowered, which is mainly based on material type and granules, material material, material moisture, material The particle size composition is equal to the maximum relationship. 1.1.1 The type of material type and the type of particulate material are different, and the physical characteristics are different. The type of material can be divided into two categories of brittleness and viscosity. During the vibration screening process, the viscous material is easily formed, and the screen is easily formed, and the screen is blocked, and the transmission rate is lowered, and the brittle material is not, the process efficiency can be guaranteed. . The particle shape of the material will also affect its translucent, the shape of the cube and the sphere is easy to screen, and the sheet material is easy to card in the screen, so that the screening process is reduced. 1.1.2 The material loose density material particles are substantially layered and transmissive in size, that is, the loose density of the material directly affects the processing power of the vibrating screen. Block-shaped bulk materials with large loose density are easy to screen, and the screening efficiency is also high; in contrast, material and powdery materials hng less loose density are not easy to screen, and the screening efficiency is also low. 1.1.3 Material humidity material is too high, easy to form adhesion, during vibration, the block is compressed to make the adhesion group more dense, increase the resistance of material movement, making it difficult to block the material particles; material Adhesions also make the sieve size, block the screen, reduce the effective screening area, and someti even unable to perform screening. Therefore, when the water content of materials is too high, the screening process should consider some remedies, such as taking measures such as drying materials. 1.1.4 Material particle size Composition of materials in the screening process is affected by many factors, the most direct and important factors are materials.The relative size of the particle size and the sieve size. The ratio of material particle size and the sieve size is referred to as relative particle size. The smaller the relative particle size, the higher the transmissive probability, and when the relative particle size is close to 1, the transmissive probability is approximately zero. Therefore, a material hng a relative particle size equal to 0.7 to 1.0 is usually referred to as a difficult sieve material or a critical material. There is also an influential impact on the sieve probability of the material in the material, the larger the content of the difficult sieve material in the material, the smaller the translation probability, the lower the screening efficiency. In order to obtain higher screening efficiency, it should be reduced as much as possible to reduce the conte of sieve materials in the aggregates. In addition, the particle size index difference has a certain impact on the screening efficiency, and the particle size index is too large, and the production cycle will be large, the quality and processing of the product are constrained. Therefore, the collapse of the aggregates should be strictly controlled. 1.2 Screen Structural Parameters 1.2.1 The length and width of the screen surface generally believe that the screen width directly affects the productivity, and the screen length directly affects the screening efficiency. Width, increased effective area, increase productivity; long sieve surface, the material is long, the screen is long, the screening opportunity, the screening efficiency is high. But the longer the longer, because the relationship between screening efficiency and the time experienced on the entire screen surface is complicated, at the beginning, due to more fine particle materials on the screen, within the unit time After a certain period of time, the material particle size remaining on the screen is a difficult sieve material close to the sieve size, even if the material is resting on the screen surface (ie, the length of the screen is very large) ), It is also difficult to increase the screening probability of the material, resulting in a decrease in the working efficiency of the screening machine. In fact, the sifter width has different degrees of screening efficiency, and the screen length has different degrees of screening capabilities. The matching of the two is also important, generally a length ratio of 1: 2 to 1: 3. 1.2.2 Sieve shape Although the shape of the screen is mainly dependent on the particle size of the sieve product and the application of the product under the sie, there is also a certain impact on screening efficiency. Compared with the other shape of the screen hole, the circular screen hole is the same as that of the nominal size, the measuring particle size transmitted by the screen is smaller, for example, the average maximum particle size transmitted through the circular screen particles is only the same size. 80% to 85% of the square screen particles; the roofed surface of the rectangular sieve is large, the sieving surface is light, large, and the material particle size transmitted through the screen is greater than the same shape. The material particle size of the square screen hole. Therefore, in order to achieve higher screening efficiency, different sieve shapes must be selected for different screening materials, which can improve the processing power of the vibrating screen. 1.2.3 The opening rate of the screen size and the screen surface is in the case of sieving material, the sieve size has a great effect on the screening efficiency. The larger the sieve size, the stronger the translation ability of the material particles, the larger the processing ability of the vibrating screen, of course, the sieve size is mainly determined by the process requireme of the sieve material. The opening ratio of the screen surface refers to the ratio of the screen opening area and the screen area (also known as the effective area coefficient). High opening rate increases the probability of material particles, and the processing ability of the vibrating screen is high. Conversely, the processing of the vibrating screenThe effort is low. Therefore, in order to improve the screening efficiency, a larger number of effective area coefficie should be selected. 1.2.4 Memory of sieve surfaces, non-metallic sieve, such as rubber grading sieve, polyamine lipids, nylon sieve, nylon sieve, etc., due to the characteristics of these non-metallic materials, in sieve Different high-frequency vibrations are generated in the process, so that the phenomenon of clogging is difficult to occur, which is conducive to the screening of the material, and improves the processing efficiency of the metal screen vibrating screen. [NextPage] 1. Vibration characteristics Parameter vibration characteristic parameters include vibration frequencies, amplitude, vibration direction angles and screen angles. 1.3.1 Throwing Index 4 Vibration Characteristics Parameters In addition to the different influences of the vibrating screen, their common influence can also be summarized as a parameter – throw strength D (or a throw index), its relationship is: d u003d ¦Ø2asin¦Â / gcoos¦Á u003d ksin¦Â / cos¦Á formula: A – amplitude (mm); ¦Ø – vibration circular frequency (rad / s); g – grty acceleration; ¦Â-vibration direction (¡ã); ¦Á- Screening angle (¡ã); k – vibration strength, k u003d ¦Ø2a / g. According to experience, when the throw strength D u003d 3 ~ 3.3, a vibration cycle of the sie is equal to the cycle of material beating, that is, the screen is vibrated once, the material will show a throwing movement, at this time, the material is the most easy to screen, this Motion status is very beneficial for reducing unnecessary energy consumption and improving the screening efficiency of the vibrating screen. However, this is based on the parameters obtained based on a single material particle beating. In fact, the material is present on the screen surface, and the material particles often generate friction, thereby requiring a larger throwing strength, so in actual A higher throw strength should be selected in the application. 1.3.2 Screening angle ¦Á screen surface and the horizontal angle of the horizontal plane are referred to as screening inclination. The size of the inclination is closely related to the amount of screening and screening efficiency of the screening equipment. When the inclination is increased, the throw strength of the material on the screen will increase, so that the material is accelerated on the screen surface, so that the amount of vibration screen is increased, but the material is shortened, and the granular screening is reduced. Thus reduced the screening efficiency. Conversely, the amount of treatment is lowered and the screening efficiency is improved. In order to control the vibrating screen sieve in a relatively ideal range, the sieve angle of the circular vibrating screen is typically at 15 ¡ã to 25 ¡ã, and the sieve angle of the linear vibrating screen is 0 ¡ã to 8 ¡ã. 1.3.3 The angle between the vibration direction angle ¦Â vibration direction and the upper screen surface is referred to as the vibration direction angle. The larger the angular value of the vibration direction, the shorter the distance movement of the material each time the movement moves, the slower the motion speed of the material on the screen surface, and the material can be sufficiently sieved, thereby obtaining a large screening efficiency. The smaller the angular value of the vibration direction, the farther the material is thrown, the farther the distance is farther, the faster the material passes through the screen, but the material is high, but the material cannot be sufficiently sieved. Therefore, the vibration direction should be reasonably selective. For difficult sieve materials, the vibration direction angle should take a large value, for easyThe sieve material, the vibration direction angle should take a small value; in general, the vibration direction angle of the circular vibrating sieve is 90 ¡ã, the vibration direction of the linear vibrating screen is 30 ¡ã ~ 60 ¡ã, which is often 45 ¡ã, this value Not only is well adapted to various screening performance, but also achieves the best movement speed and higher productivity. 1.3.4 Amplitude A amplitude A increased, and the screen jam will be greatly reduced, and it is also conducive to the layering of materials. But the amplitude is too large to the equipment. The choice of amplitude is determined based on the particle size and properties of the sieve material. In general, the larger the vibrating screen specification, the greater the amplitude selected. When a linear vibration screen is used for classification, the amplitude is slightly large; when the particle size treated is large, the amplitude should also increase accordingly; the granular particle size is small, and the amplitude should be small. Typically, the amplitude A u003d 3.5 ~ 6 mm of the linear vibrating screen. 1.3.5 Vibration Frequency ¦Ø vibration frequency increases, can increase the number of ti of jump on the screen, so that the screening probability of the material is increased, which is very helpful for speeding the material screening speed and improving the screening efficiency, but too high It will reduce the service life of the device. The selection of usually the vibration frequency is determined by the vibration intensity K and amplitude A. The relationship between them is: ¦Ø2 u003d 3 600k ¡¤ g ¡¤ COS¦Á / (a u200bu200b¡¤ sin¦Â) for high particle size, select a large amplitude and lower frequency; for material material, smaller Amplitude and higher frequency. 2 Improve the effectiveness of vibrating screen Working efficiency 2. Selecting a suitable vibrating screen type Although the screening effect depends primarily on the nature of the sieve material, the same material can obtain different sieving effects. If the screening efficiency of the fixed screen is low, the screening efficiency is related to the motion form of the sieve surface, and the particles are jitter in the direction of the vertical screen, the vibration frequency is High, the better the screening effect; on the shake screen sieve surface, the particles are mainly pulled along the screen. Since the rocking frequency of the shaking screen is lower than the frequency of the vibration screen, the screening effect is poor; cylindrical sieve The screen is easy to blocked, so the screening efficiency is low. Therefore, the vibrating screen type should be rationally selected according to the properties of the material to maximize the efficiency of work efficiency. If the material is pre-sieved and inspected, the screen is generally used in a circular vibrating screen; the crushing material is graded using a probability screen, such as a thick screen and a large vibrating screen; subjection and demerane, using a probability screen The sieve effect is better. In order to improve the efficiency of the vibrating screen, it is necessary to use a large number of sieve size, larger effective screening area, and the higher sieve opening ratio as much as possible in the premise of satisfying product particle size requireme Metal sieve. And use the appropriate screen shape to improve the screening capacity and productivity of material particles. [NextPage] 2.2 rationally selecting the rational selection of the vibrating motor and adjust the excitement vibrating motor is one of the key links affecting the vibrating screening, and the excitation force is a core factor affecting the productivity of the vibrating screen. 2.2.1 Selection of vibrating motors as the vibration source of the vibrating screen, should have the advantages of reasonable design, simple structure, compact, exciting efficiency, energy sng, easy installation and commissioning, etc., the selection of the vibrating motor includes the operating frequency, maximum excitation Force, power and other parameters. The first is to select the operating frequency and exciting force, the speed of the vibrating motor is close to the operating frequency; the maximum excitation force must be in the range of the selected motor synthesis excitation. The power of the vibrating motor is then selected based on the operating frequency and the maximum exclusion force. 2.2.2 The adjustment of the vibration force The productivity of the vibrating screen is indexed with an index relationship. The increase in excitation power increases rapidly, and the clogging rate increases rapidly with the increase of excitation. The increase in excitation allows the vibration intensity, and the force of the screen is increased, and the speed of the material is increased, the productivity is improved, and the clogging rate is lowered. The excitation force has a certain impact on the pass rate and the breaking ratio of the sieve, and the variation of the variation is wavy. When the excitation force is too small, the pass rate and the crushing rate are poor; when the excitation force is too large, the friction of the eccentric pieces on both ends of the vibrating motor rotation will increase, in the case of high speed rotation, it is easy to damage the motor, reduce the motor. Life, therefore is very important to reasonably adjust the size of the excitement. The vibration force of the vibrating motor is the centrifugal inertia generated by the eccentric block of high speed. Change the eccentricity, thereby changing the magnitude of the exciting force, can achieve the effect of adjusting the exciting force. 2.3 Improvement of screening surface motion mode The working efficiency of the vibrating screen is greatly affected. The ideal sieving mode should be: 1 The amplitude of the vertical direction of the screen surface injection should be larger than the exhaustion of the discharge end. This is because the injection end has a large vertical amplitude, which can make the thick material to be substituted, while using the inclination angle, the excess material is quickly spread to the middle of the screen, so that the fine particle material is relatively The thin material layer is separated from the actual use area of u200bu200bthe screen surface; when the material reaches the discharge end, the material has been divided, and only a small vertical direction amplitude can guarantee fine particle materials. There is a good screening condition, too large vertical amplitude, reversing the screening environment of the fine particles. 2 In the direction of the screen surface, start from the feed end, the material movement speed should be a decreased state. This is because the motion speed of the material is decreasing, allowing the material layer to maintain a certain thickness over the entire screen surface, so that the fine particle material is separated from the relatively longer sieve surface, increase the actual use area of u200bu200bthe sieve, and at the same time, The sieve surface along the screen length direction tends to be uniform, and the screening potential of the screen surface is given. For nearly a few years, the other thick sieves and dual-frequency vibrating screens have overcome the disadvantages of the entire screen amplitude of ordinary vibrating screens as the constant value and the unite screening ability, so that the feed end has a larger amplitude, the discharge end has And the same amplitude as the ordinary vibrating screen, thereby improving productivity. Recently, some scholars have obtained a new type of vibrating sieve-complicated motor trajectory vibrating screen, which is simple in structural, simple, high power consumption, and high work efficiency. The screen is moved in the feed end screen, and the middle screen surface is elliptical.The discharge end is an arc motion that is approximately straight, and the sifting direction of the sieve length direction is changed by point-by-point, and the moving speed in the screen length direction is decreasing. This improves both screening efficiency and work efficiency, and reduces production costs, which is an ideal sieving movement. 2.4 Using a non-metallic material screen using a thin elastic screen as a screening group, it is advantageous to improve the working efficiency of the vibrating screen. This screen is generally processed with rubber or polyurethane material, which reduces the sieve surface and the sieve material, so that the material produces second high-frequency vibration to avoid screening, and enhance the permeability of materials. And can alleviate the mechanical action of the sieve material to the screen, and the wire screen can be subjected to a large amplitude vibration. Non-metallic sheets have the following advantages: 1 Improve screening efficiency. It increases by about 15% by the screening efficiency of the metal screen. 2 Wear resistance and long service life. Its average life is over 2.5 ti the metal screen. 3 Reduce the installation time and improve the operating rate of the equipment. Since the service life of non-metallic material screen is greatly extended, the number of ti of screening is reduced, and the equipment operating rate is generally increased by 15% more than the metal screen. 4 Reduce noise and improve the work environment. Metal screening except for the sieve tank resonance, the h is also trembled, and this phenomenon is more obvious after wear, plus the steel collision of the material on the box and the vibration of other compone, and the resulting noise is higher. The entire screen plate of the non-metallic material screen is a whole, with a certain buffer, and can reduce noise 20 dB (a). 2.5 Multi-channel feed mode is typically used in all the way, and after the material is supplied to the sie, most of the materials smaller than the separation particle size will become sieved under the screen through the feed end, and the discharge The side of the 1/3 to 1/2 of the end, in addition to continuing a certain screening effect, it mainly serves as a function of transportation, so the utilization rate of the screen is not high. If multiple feed is used, it is equivalent to increasing the width of the screen surface, which reduces the thickness of the material supplied to the screen surface, which is advantageous for the fine particle material soon contact the screen through the screen, while fully utilizing the screen surface Reduce the unnecessary transportation of crude particles, thereby improving the screening efficiency. 2.6 Strengthening operational management operations and maintaining a certain impact on vibrating screening performance. In order to operate the vibrating screen, it must be carefully operated in accordance with the operation procedure, such as the feed is uniform, continuous and appropriate amount, ensuring that the material is uniformly distributed throughout the entire screen surface, to facilitate fine particles, and obtain a higher processing ability. And screening efficiency. In addition, it is necessary to strengthen the maintenance and maintenance of the screening machine, such as cleaning the screen and repair, replacing the damaged screen, ensuring the intact of the equipment. 3 Splitting the vibrating screen is the main equipment of the screening process, the design and manufacturing, process operation, maintenance and maintenance and operation management of the screening process, which has a large impact on the normal and reliable operation of the equipment, which in turn affects the efficiency and product quality of process production. . Master the influencing factors and regularities of vibrating screen sieve and improve the efficiency of vibrating screen sieve, which is important for ensuring sieving process engineering, high-yield is of great significance.. There are many factors affecting the efficiency of the vibrating screen sieve, improve the working efficiency of the vibrating screen, to take appropriate measures according to the actual situation, comprehensively consider, to maximize screening efficiency under the premise of ensuring the processing. At present, the vibrating screen products are moving towards large, heavyization, spatialization, standardization, series, generalization, etc., seek new vibration forms to improve processing capacity and screening efficiency, and perform screening machinery system optimization, Solving the reliability, fatigue life, vibration, and noise pollution problems, research, etc. Reference [1] Shen Xiangzhi. Analysis of the factors of vibrating screening efficiency [J]. ¿ì ¿ì±¨, 2007 (5): 86-87. [2] À¼ À¼, ÉÙ Ãô. Optimization design of reciprocating vibration screen motion parameters [J] Journal of China, 2001 (3): 60-62. [3] Li Yufeng, Li Yongzhi, Pan Dongming, et al. Determination of Linear Vibration Screen Movement [J]. Coal Mine Machinery, 2008 (3): 33-34 [4] Wang Hongbing, Zhang Lu Xia. Some factors affecting the simultaneous effect of linear vibrating screen [J]. Modern Manufacturing Technology and Equipment, 2008 (4): 29-31. [5] Wang Cuiqing, Yilong River. Impact line vibrating screen Several important parameters of the sub-effect [J] .Charming technology, 2006 (2): 13-14. [6] Zhang Zhongyuan. Ways to improve vibrating screen processing capacity [J]. ½ð, 2000 (7): 36-38 .

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