As we all know, if you want to choose a vibrating screen, the first thing you need to consider is what materials you need to screen, and choose the vibrating screen according to the materials. If the material screened by the vibrating screen is not matched with the equipment type and is not suitable, then there will be many problems, such as the vibrating screen does not go away, does not go down, the screening accuracy is not high. The type of vibrating screen is many, each type of vibrating screen is suitable for screening different materials, so how to choose the vibrating screen according to the material?
一.According to the material properties of the selection
1.Density
The difference in material density has a significant impact on the choice of vibrating screen. For denser materials, such as ores, metal particles, etc., during the screening process, they need greater excitation force to achieve particle beating and stratification to pass through the screen smoothly. Therefore, heavy duty vibrating screens and circular vibrating screens become the ideal choice for such materials. Heavy vibrating screen structure is sturdy, can withstand large impact load, and its strong excitation force is enough to drive the high-density bulk materials on the screen surface to achieve high efficiency screening, suitable for large particle size, relative density of materials screening, such as mining on the rough screening of raw ores. Circular vibrating screen, on the other hand, through the circular motion, generating a large centrifugal inertia force, so that the material on the screen surface to do circular motion, also can effectively deal with the density of materials, widely used in the field of mining in the fine grain material screening.
On the contrary, for smaller density materials, such as plastic particles, lightweight fibres, etc., too high excitation force may lead to excessive flying materials, or even escape from the screen surface, affecting the screening effect and production environment. At this time, linear vibrating screen or rotary vibrating screen is more suitable. Linear vibrating screen material movement trajectory for straight line, amplitude and excitation force is relatively mild, can make the light material in the screen surface smoothly jump forward to achieve screening; rotary vibration sieve through the vertical vibration motor drive material to do turnover movement, the movement is more gentle, but also can be well adapted to the screening needs of low-density materials, commonly used in food, medicine, chemical industry and other industries on the lightweight materials of fine screening.
2.Corrosive
Corrosive materials, such as acid, alkali solution and some chemical reagents, etc., in the screening process will have a corrosive effect on the contact parts of the vibrating screen, which requires the vibrating screen to have good corrosion resistance. From the material selection, stainless steel has become the first choice. It can effectively resist the erosion of strong acid and alkali, and ensure that the vibrating screen can run stably for a long time in the harsh chemical environment.
In the structural design of the vibrating screen, it is also necessary to consider the anti-corrosion factors. For example, try to reduce the gaps and dead corners in the structure to avoid the accumulation of corrosive materials, thus reducing the risk of corrosion; the use of components with good sealing performance to prevent the leakage of corrosive gases or liquids, and further protect the other parts of the equipment from corrosion.
3.Conductivity
Some materials are prone to static electricity in the screening process, such as plastic granules and powder materials. The presence of static electricity will make the material adsorbed on the screen surface, resulting in clogging of the screen holes, but also may lead to potential safety hazards. For this kind of material with conductivity, usually choose the vibrating screen with anti-static function. A common method is to add anti-static material in the vibrating screen screen material, such as stainless steel screen mesh in the addition of special conductive fibers, so that it has good electrical conductivity, can be timely to the material produced by the electrostatic conductive, to avoid static electricity accumulation. In addition, it can also be set in the equipment around the static electricity elimination device, to further ensure the safety and smoothness of the screening process .
二.The size of the particle size
1.Large particle material (more than 200mm)
For large particles of materials with a particle size of 200mm or more, such as large ores, coal, etc., heavy vibrating screen is the right choice. Heavy vibrating screen is specially designed for processing large particles and large output materials, and its structure is sturdy and durable, made of high-strength steel, which can withstand the great impact and wear of large particles in the screening process. It is equipped with a high-power exciter, which can generate strong vibration force to drive the large particles of material on the screen surface fully jumping and tumbling, to achieve rapid screening.
2.Medium grain size (10 – 200mm)
For materials in the medium particle size range (10 – 200mm), circular motion screens show unique advantages. Circular motion screen, such as circular vibrating screen, its work when the screen box to do circular movement, the material in the screen surface also do circular movement. This trajectory makes the material in the screen surface movement speed is faster, can increase the material and screen hole contact opportunity, thus improving the screening efficiency. In the production of sand and gravel aggregate, after the crusher processing of medium size sand and gravel, through the circular vibrating screen for screening, can be different size sand and gravel accurate classification, to meet the needs of the construction industry for different specifications of sand and gravel aggregate. Circular vibrating screen also has a simple structure, easy maintenance, long service life and other characteristics, which further makes it become the ideal equipment for screening medium size materials.
3.Small particle material (10mm or less)
When the material particle size of 10mm or less, the screening accuracy and efficiency requirements are higher, linear vibrating screen and high frequency vibrating screen has become a common choice. Linear vibrating screen through the two synchronous reverse rotation of the vibration motor, so that the screen body produces linear vibration, the material in the screen surface to do linear jumping movement. This movement makes the movement of materials on the screen surface more stable, and can effectively avoid excessive accumulation of materials and blockage of sieve holes, which is suitable for fine screening of small granular materials.
High-frequency vibrating screen stands out with its high frequency and small amplitude in the screening of small granular materials. Its vibration frequency can usually reach more than 50Hz, can quickly break the adhesion between the materials, so that small particles of material quickly through the sieve holes, to achieve high efficiency screening.
三.The shape of the difference
1.Lumpy materials
Lumpy materials usually have a large volume and irregular shape, and the main purpose of its sorting is to quickly sort out the particle size of large particles. In the ore sorting, coal sorting, glass sorting and other industries, often encounter such lumpy materials. For their screening, most of the selection of single-deck high-efficiency vibrating screen. This kind of vibrating screen has high efficiency, the motor is designed at the top or in the middle, and the box plate is thicker, which can withstand the impact and abrasion of lumpy materials. According to the different running trajectories of materials, it can be divided into two kinds of circular vibrating screen and high efficiency mining screen. When the circular vibrating screen is working, the screen box does circular movement, and the materials also do circular movement on the screen surface, this movement can make the materials jump and roll quickly on the screen surface to achieve rapid screening, and the design of large mesh facilitates the passage of lumpy materials to avoid clogging. High-efficiency mining sieve also has a strong screening capacity, can meet the screening needs of lumpy materials in mining and other industries.
2.Granular materials
Granular material classification generally refers to the screening of less than 10 mm, 0.5 mm or more, belonging to the range of granular materials. In the screening process of this kind of material, it is necessary to ensure the fineness and efficiency of screening, and at the same time to prevent the leakage of materials. Linear vibrating screen becomes the ideal choice for screening and grading granular materials because of its unique advantages. It has a good sealing effect, which can effectively avoid the leakage of materials in the screening process and keep the production environment clean. Materials in the linear vibrating screen screen surface along the screen to do forward linear jumping movement, this movement makes the material in the screen surface movement is more orderly, can increase the material and screen hole contact opportunity, so as to achieve high efficiency screening.
四.The application of industry
1.Mining, coal industry
The materials handled by the mining and coal industries are usually characterised by large volume, coarse particle size, high hardness and strong abrasiveness. In mining, the raw ore extracted from the ground often contains various sizes of particles, which need to be preliminarily screened and graded to meet the requirements of subsequent crushing, grinding and other processes. The coal industry also needs to screen the mined coal, remove gangue and other impurities, and classify the coal according to particle size to meet the needs of different users.
For these industries, linear vibrating screen and mining vibrating screen are commonly used equipment. Linear vibrating screen has the advantages of large handling capacity, high screening efficiency, simple structure, easy maintenance and so on. Its screen surface is horizontal or slightly inclined, and the material makes linear movement on the screen surface, which can quickly pass through the screen mesh and achieve efficient screening.
2.Food, pharmaceutical industry
The food and pharmaceutical industries have very high requirements for product health, safety and quality, and any tiny impurities or uneven particle size may affect the quality and safety of the product. In food processing, such as flour, icing sugar, milk powder and other raw materials sieving, need to remove the impurities and lumps, to ensure that the product size is uniform, fine taste . In the pharmaceutical industry, the particle size control of raw materials and finished products is more stringent, as different particle sizes may affect the solubility, absorption and efficacy of the drug.
3.Laboratory scene
In the laboratory, the screening of materials often need to accurately control the particle size, to obtain accurate data for scientific research and experiments to provide reliable support. Laboratory screening work is usually small, but the precision and stability of the equipment required is very high. Experimental screening equipment came into being, it has a small size, easy to operate, high screening precision, accurate data and other characteristics, to meet the laboratory screening requirements for a variety of materials.
Experimental screening equipment usually adopts high-precision screen mesh and advanced vibration control technology, which can achieve accurate classification of materials.
Selecting the right vibrating screen is a complex and systematic project, which needs to comprehensively consider many aspects of the material’s properties, particle size, shape, application industry and screening purpose. The neglect of any one factor may lead to the mismatch between the vibrating screen and the material, thus affecting the screening effect and production efficiency. Therefore, in the selection process, it is necessary to comprehensively and meticulously analyse the characteristics of the material to ensure that the selected vibrating screen can meet the needs of actual production.
