What Is a Vibrating Screen?

The vibrating screen works by using the reciprocating rotary vibration generated by the vibrator. The upper rotating weight of the vibrator causes the plane surface to vibrate on the sieve surface, while the lower rotating weight causes the screen surface to generate conical surface rotation vibration, and its combined effect causes the screen surface to generate a multi-rotational vibration. Its vibration trajectory is a complex spatial curve. The curve is projected as a circle in the horizontal plane, and is projected as an ellipse in the vertical plane. Adjust the excitation force of the upper and lower rotating weights to change the amplitude. Adjusting the spatial phase angle of the upper and lower hammers can change the curve shape of the trajectory of the sieve surface and change the trajectory of the material on the sieve surface.

It is a kind of filtering mechanical separation equipment used for solid phase treatment of mud. It consists of screen and vibrator. The thickness of the screen is expressed by mesh. Generally, those below 50 mesh are coarse sieve, and those above 80 mesh are fine sieve. The vibrator is an eccentric wheel, which is rotated by a motor to cause the screen frame to vibrate. Due to the vibration of the screen frame, coarse solid particles remain on the screen surface when the slurry flows on the screen surface, and are discharged from one end along the inclined surface. The finer solid phase particles and the slurry liquid flow through the screen holes to the mud pool together. .

The main types of vibrating screens: product advantages and disadvantages: high efficiency, light weight, complete and diverse series,

Vibration screening equipment can be divided into:

Before leaving the factory, the equipment needs to be assembled, assembled and tested without load. The equipment can only be delivered after passing the inspection. Therefore, after the equipment is delivered to the site, the user should check the entire machine according to the packing list and the complete equipment delivery note. Whether the parts are complete and whether the technical documents are missing.

It is mainly composed of screen box, shaker, suspension (or support) device and motor. electric

A vibrating screen is generally composed of a vibrator, a screen box, a support or suspension device,

The crushed material groups with different particle sizes are repeatedly sieved through a single-layer or multi-layer sieve surface with uniform holes, and divided into several different levels to become sieving. Particles larger than the sieve are left on the sieve surface and are called the sieve on the sieve surface. Particles smaller than the sieve pass through the sieve and are called the sieve on the sieve surface. The actual sieving process is that after a large number of granular materials with different particle sizes and mixed thicknesses enter the sieve surface, only a part of the particles are in contact with the sieve surface. Due to the vibration of the sieve box, the material layer on the sieve is loosened, so that large particles exist The gap was further enlarged, and the small particles took the opportunity to pass through the gap and transferred to the lower layer or the transport plane. Because the small particles have a small gap, the large particles cannot pass through, so the original cluttered particle group was separated, that is, the particles were layered according to the size of the particles to form a regular arrangement of small particles below and coarse particles above. The fine particles that reach the sieve surface are smaller than those who pass through the sieve, and finally the coarse and fine particles are separated and the sieving process is completed. However, sufficient separation is not available. Generally, a part of the under-sieve remains on the sieve during sieving. When the fine particles are sieved, although the particles are smaller than the sieve holes, they have different easiness of sieving. It is more difficult to pass through the sieve when the materials and the sieve size are similar, and it is even more difficult to pass through the particle gap below the sieve.

Use the block eccentricity as the excitation force, which is strong.

The screen beam and screen box use high-strength bolts, which are simple in structure and convenient and quick to maintain;

The scope of application of the vibrating screen is very wide. It involves almost every aspect of life. Various types of vibrating screens are used in processing and manufacturing.

Vibrating screen is mainly used in mining, coal, smelting, building materials, refractory materials, light industry, chemical industry, medicine, food and other industries.

Vibrating screens are most commonly used in mineral processing plants.

1. Sieve design, compact and easy to assemble, one person can operate the sieve.

2. Compared with other types of screening equipment, it has a larger screening area and high efficiency processing capacity.

3. Unique screen structure design, easy and fast screen replacement (it only takes 3 to 5 minutes), besides this design

Various screens (nylon, special dragon, PP mesh) are allowed.

4. Its parent network fully supports the fine mesh, so the fine mesh can have a long life alone, while reducing the use of fine mesh consumables, and the long production process can reduce many costs.

Function and principle:

The basic principle is to use the weights (unbalanced weights) installed at the upper and lower ends of the motor shaft to convert the rotary motion of the motor into horizontal, vertical and inclined three-dimensional motion, and then convey this motion to the screen surface. If the phase angle of the upper and lower weights is changed, the traveling direction of the raw materials can be changed.

Inspection before running the vibrating screen: including sanitation of the equipment, all parts of the connection bolts are complete, fastened and intact, check whether the shaker is intact, check all springs

With the further development of China's economic construction and scientific research, new vibrating screens will continue to appear, their use in various sectors will also increase, and they will play an increasingly important role.

As part of the work of the vibrating screen is a delicate operation, problems such as these cannot be avoided during operation. Sometimes the material is discharged when the material is sieved. At this time, the material screening can be adjusted by adjusting the upper and lower hammers. To achieve better results.

First of all, we can adjust the additional weight of the vibration motor. An additional weight is installed on one side of the upper and lower hammers (upper and lower eccentric blocks). This can increase the excitation force of the vibrating screen. The number of layers of the vibrating screen is different, it is appropriate to increase or decrease the excitation force and adjust the amount of additional weight. Secondly, the phase angle of the upper and lower weights of the vibrating motor can be changed, which changes the material in the vibrating screen.

1.Poor motor rotation

2. Alien sound

3. Raw materials cannot be automatically discharged

4, fine mesh is easy to break

5.The outlet of the discharge frame is cracked

Daily maintenance:

1. Before startup: check the coarse and fine nets for damage, and whether each set of ring is locked

2. When starting: pay attention to whether there is abnormal noise, whether the power supply is stable, and whether the vibration is abnormal.

The pharmaceutical industry has a close relationship with people s bodies, so the country has strict requirements on the pharmaceutical industry.

The pharmaceutical industry also has strict requirements for the screening of materials. The most basic is that the vibration screening equipment used in the pharmaceutical industry must be stainless steel 304 or even 316. The contact with the material is not allowed to be contaminated by impurities, so rubber accessories must also be Food-grade hygiene standards (silica gel), and screening equipment required by the pharmaceutical industry must pass GMP production standards. The use of vibrating screens in the pharmaceutical industry has very strict requirements, which must meet the GMP production standards of the pharmaceutical industry, which is related to whether the drugs called through the screen will be contaminated.

In fact, as a non-complex screening machine, the so-called

1. Check whether the attached safety splint is removed before starting.

2. Check that all locking parts are secure.

JB 20034-2004 medicinal vortex vibratory screening machine

JB-T 2444-1999 Block type double-shaft vibrating screen for coal

JB-T 5508-2004

Screening factors affecting vibrating screen

The technical and economic indicators of the screening process are screening efficiency and productivity, the former being the quality index and the latter being the quantitative index. There is a certain relationship between them, and it is also related to many other factors that determine the results of screening. The factors that affect the screening process can be roughly divided into three categories:

Physical properties of screened material

Including the particle size composition, humidity, mud content and particle shape of the material itself.

When the content of fine particles is large, the productivity of the sieve is also large. When the humidity of the material is large, the screening efficiency will generally decrease. However, the larger the size of the sieve, the smaller the effect of moisture. Therefore, for wet materials with large moisture content, in order to improve the screening process, generally, the method of increasing the sieve can be used, or wet screening. The material with large mud content (when the mud content is greater than 8%) should be wet-screened or washed in advance.

Influence of screen surface structure parameters

1. Sieving: Sieving is to divide particles and powder into particle segments of different sizes. A single vibrating screen can be equipped with 4 layers of screens, which can continuously sort out 2-5

1. Development towards high efficiency and high output: The modernization of industry has promoted the expansion of the enterprise scope, greatly improved the production capacity of sand making equipment, and matched with high-efficiency and high-capacity screening machines.

2. Development towards standardization, serialization, and generalization: This is a way to facilitate planning and construction of specialized production, and to ensure quality and low costs. According to the three different trajectories of the vibrating screen, different screening methods are accepted, and according to the special requirements of the people's economy in various industries, various situations of vibrating screening equipment have been formed, and they have been widely used in the industrial sector.

3. Increase of vibration intensity: The vibration process of the sieve machine is gradually strengthened, that is, the vibration parameters of the sieve machine are increased to obtain greater speed and acceleration.

4. Development towards light weight, environmental protection, and simplified layout: The old vibrating screen in the 1980s was inconvenient to change the screen. There were 48 netting bolts per layer, and the time for changing a screen was at least 4 hours, and the powder had a high mesh count. It is easy to leak out from the bolt. With the continuous increase of the requirements of the vibrating screen in the industrial sector, old-style vibrating screens will be gradually phased out. In order to meet the requirements of the industrial, chemical and other sectors, the new vibrating screen should be developed in the direction of light weight, environmental protection and simplified layout.

From the National Bureau of Statistics, in 2010, Feng Chaoyang, Secretary General of the Professional Committee for Washing Equipment, said that driven by the development of coal, iron ore, non-ferrous mines, steel, chemical, power generation, cement and other industries, the vibrating screen industry will maintain strong demand. the amount. It is estimated that the total demand for shakers in 2010 will reach 9.23 billion yuan. ^[11]

According to the latest media survey, domestic enterprises engaged in the vibration machinery industry are mainly concentrated in Xinxiang, Hebi, Henan, Nantong, Xuzhou, Anshan, Chaoyang, Shanghai, Tianjin, Tangshan, Hebei, Foshan, Guangdong, Songzi, Jinan, Shandong, and Shaoyang, Hunan. Few regions. Henan Xinxiang has absolute advantages in the field of vibration machinery production, research and development and manufacturing, mainly divided into two types of light screening machinery and heavy vibration screening machinery.

Application of vibrating screen in paper industry:

1. Preliminary sorting of dry lime into slurry lime pond

Purpose: To ensure the uniform particle size of the materials entering the slurry lime pond;

1. Paper filler (customer materials: slurry calcium carbonate and slurry titanium dioxide)

Purpose: To improve the accuracy of papermaking fillers;

1. Paper white water--medium:

   Model of shaker screen box

   Using finite element analysis ANSYS software to establish the finite element model of the screen box, there are two methods, one is to directly use ANSYS software to build the solid model of the screen box, or to build the solid model in the PRO / E software and then import it into ANSYS. This method takes a long time to model and calculate, and the ideal result may not be calculated. The second method is to use the shell and plate elements in ANSYS software to build a finite element model of the screen box. Fast, fast calculations and accurate results.

   During the use of the vibrating screen, there will be various problems. Among them, through the continuous analysis and summary of the occurrence of slurry running, it is mainly screened with high solid content in the drilling fluid, high viscosity of the mud, and dispersion of cuttings. The material is related to the vibration conditions of the vibrating screen, the screen mesh number is small, and the screen area is small. It also has a lot to do with the direction and position of the liquid inlet of the vibrating screen during field installation. Several points can do some analysis.

   1. The number of screen meshes used is unreasonable. The processing capacity of each vibrating screen is 50L / s. This is because the testing conditions of the processing capacity are in accordance with national standards: a 60-mesh screen is selected, and the specific gravity is 1.8 weighted mud for testing. The viscosity of the mud is different. River sand. Due to the rapid drilling of the surface layer, a large amount of solid phase is used to occupy the effective screen area. Therefore, fine screens cannot be used in shallow sections. Therefore, a larger hole screen should be used at the beginning of drilling. As the drilling depth increases, a finer screen is gradually adopted.

   2. Strata and mud conditions affect throughput. Alternatively, when drilling into a loose sandy formation or quicksand

   3. During the layer, sand particles are easily stuck in the screen holes, causing screen blocking. Therefore, several screens with different mesh sizes should be tested to reduce the sieve blocking phenomenon.

   4. Check that the motor is turning correctly. First remove the shroud of the vibrator and check whether the eccentric blocks of both motors rotate outward. Secondly, if the steering is wrong, please replace any two phase wires in the incoming power of the electric control box. Wrong way one (the two motors rotate toward the inside), although the cuttings can also be removed, but the speed is slow; Wrong way two (the two motors rotate in the same direction), the vibration force is very small, and the sand is basically not discharged or treated with mud .

   5. Check the amplitude of the shaker. The larger the vibration amplitude, the larger the processing capacity; the vibration force is adjusted to 90% when leaving the factory. If running pulp occurs, you can align the inner and outer eccentric blocks with an angle of 100%. (At this time, the amount of mud treatment has only increased by about 15%)

   6. Check whether the flow distribution on the screen frame is reasonable. The vibrating screen with hook screen structure has lower screen surface on both sides and mud

   7. It is easy to flow to both sides and run away. Make sure that the mud enters the screen frame from the middle. At this time, two schemes can be adopted. One is to adjust the front spring seat to appropriately increase the angle of the front of the screen box; the other is to adjust the position of the flip plate of the extension groove to control the flow distribution.

   The vibrating screen is operated by using a vibrator-type multi-rotational oscillation. The upper rotating weight of the vibrator causes plane oscillating oscillations on the sieve surface, while the lower rotating weight causes conical surface oscillations on the sieve surface, and its combined effect causes the sieve surface to oscillate repeatedly. In normal operation, how to prevent the vibration screen bearing from being damaged, let's discuss it together:
   When the eccentric block of the device is dropped after long-term use or the size of the eccentric block is not common, the linear oscillating shaker shaker symmetry eccentric block layout occurs at high speed. Will cause abnormal equipment speed. At this moment, the layout of the eccentric block should be replaced in time. The two tending blocks of the linear oscillating sieve are the same size and work in balance. After the speed of the bearing of the linear oscillating screen is abnormal, it is easy to cause conflict and temperature rise. When the bearing of the linear oscillating screen is short of smooth oil or the increase of smooth oil does not meet the equipment requirements, which will cause the blockage of the vibrating screen labyrinth sealing equipment, the temperature rise of the bearing layout will exceed the regular scale value. At this moment, it is necessary to check the smooth system of the equipment in time. The smooth oil is hygienic enough. If the appearance of blockage is found, the bearing should be installed for thorough hygiene. If the seal is damaged or the bearing is cracked after wearing, the seal and bearing should be replaced in time. Adjust the linear vibration screen from the beginning. After heavy. ^[13]