What should I do if the vibrating screen runs out? The reason and treatment method of running pulp

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Mining vibrating screen can be used not only for powder materials, but also for the screening of liquid materials such as coal slime. However, unlike powder materials, powder materials are easy to accumulate, while liquid materials It is easy to flow out, which is the so-called slurry phenomenon. So what should I do if the vibrating screen runs out? At this time, it is necessary to analyze the reasons for the running pulp first, in order to better deal with it.

The reason why the vibrating screen runs out of pulp

High frequency dehydration vibrating screen

1. Influence of formation and mud

The influence of formation and mud is divided into the following two cases:

(1) When drilling into a loose sand-bearing layer or quicksand layer, the sand particles are easily stuck in the screen holes, resulting in the phenomenon of slurry running.

(2) Since the drugs added in the drilling fluid are not fully dissolved and stick on the screen, serious slurry running will occur at this time.

2. Unreasonable mesh number

The unreasonable mesh size of the selected screen will easily cause the slurry to run away. The processing capacity of each vibrating screen is 50L/s, because the conditions for the processing capacity test are according to the standard: 60 mesh screen is selected, and the test is carried out on the weighted mud with a specific gravity of 1.8, and the mud viscosity is the river with different particle sizes in the mud. sand. Due to the rapid drilling of the surface layer, a large amount of solid phase is generated and occupies the effective screen area, so the vibrating screen cannot use fine screen in the shallow well section.

3. Vibrating screen amplitude is too small

The vibration amplitude of the vibrating screen generally determines the processing capacity. If the amplitude is too small, it is easy to cause material accumulation, and it is easy to cause slurry running for coal slime slurry materials. Usually the vibration force of the vibrating screen is adjusted to 90% at the factory.

4. Uneven distribution of liquid flow in the screen frame

The uneven distribution of liquid flow in the screen frame is also the reason why the vibrating screen runs out of slurry. In the vibrating screen of the hook screen structure, the surface of the screen on both sides is lower than that in the middle, and the mud is easy to flow to both sides and escape.

5. The vibration motor turns incorrectly

If the vibration motor is turned inward by mistake, although the projection angle is also forward, the liquid flow has the force to push backward. At this time, the speed of the liquid flow moving forward is much slower, and it stays on the screen for a long time. It will cause the liquid flow to be unable to discharge, resulting in the phenomenon of running slurry.

The method of dealing with the slurry running of the vibrating screen

Linear vibrating screen

1. Experiment with different meshes

First, try several screens with different mesh numbers to see which one is more suitable, so as to solve the phenomenon of slurry running. Secondly, it should be used after the drug is fully dissolved, or a larger mesh screen should be used.

2. Different screen meshes are used in sections

In the early stage of the use of vibrating screen drilling, a screen with a larger mesh should be used, and as the drilling depth deepens, a screen with a finer mesh should be gradually used.

3. Check the vibrating screen amplitude

The larger the vibration amplitude is, the larger the processing capacity is; the vibration force is adjusted to 90% at the factory. If the slurry is running, the angle of the inner and outer eccentric blocks can be aligned, and the vibration force is 100%. (At this time, the treatment volume of the mud is only increased by about 15%)

4. Check the flow distribution

That is, to check whether the liquid flow spreads on the screen frame reasonably, the mud should enter the screen frame from the middle. At the same time, two solutions can be adopted. One is to adjust the front spring seat to properly raise the angle of the front of the screen box; the other is to adjust the front spring seat. Adjust the position of the turning plate of the elongated tank to control the distribution of liquid flow.

5. Check the vibration motor steering

First remove the shield of the vibrator, check whether the rotation direction of the eccentric hammers of the two motors can both rotate to the outside, and secondly, if the rotation is wrong, please exchange any two phase wires in the incoming power supply of the electric control box. The two motors rotate inward), although they can also sweep out the cuttings, but the speed is slow; in the wrong method (two motors rotate in the same direction), the vibration force is not very large, and neither sand nor mud is disposed at all.

The above is the answer to how to do the slurry running of the vibrating screen. First of all, we analyze the reasons for the slurry running. It is mainly affected by formation and mud. For example, the added drug is not fully dissolved and sticks on the screen; the selected screen mesh is unreasonable, and it is easy to cause slurry to run; the vibration screen amplitude is too small, etc. Then it should be solved according to the specific reasons, such as using different screens in sections.

How to improve the screening accuracy of vibrating screen? Reasons for low accuracy

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As an important screening equipment, vibrating screen is now more and more widely used in various industries. For different industries, the vibrating screen has different model size, screening accuracy and output. For example, in the mining industry, the general vibrating screen equipment model is relatively large. How to improve the screening accuracy of the vibrating screen in the screening work of different materials, let’s take a look at it in detail.

Reasons for the low screening accuracy of vibrating screen

Linear vibrating screen

1. The mesh of the screen is blocked

Solution: increase the anti-clogging device; develop the habit of cleaning the screen of the vibrating screen frequently, and reduce the load of the vibrating screen.

2. The material has high moisture and viscosity

Solution: put it into the vibrating screen after proper drying; change the inclination of the screen box.

3. Uneven feeding on the screen surface of the vibrating screen

Solution: increase the material flow divider; adjust the feeding amount of the vibrating screen appropriately.

4. The material layer on the screen surface of the vibrating screen is too thick

Solution: increase the material flow divider to control the feeding amount; tighten the screen and tighten the transmission belt. Let’s talk about how to improve the screening accuracy of the vibrating screen.

Measures to improve the screening accuracy of vibrating screen

Arc vibrating screen

1. Adjust the vibration frequency

Adjust the vibration frequency of the vibrating screen. In the operation of the equipment, if you want to achieve higher screening accuracy, you can adjust the vibration frequency to achieve the purpose of improving the screening accuracy. The higher the vibration frequency of the vibrating screen, the faster the moving speed of the material on the screen surface, and the higher the jumping height of the material on the screen surface, which is more conducive to the penetration of small particle materials.

2. Using two vibrating screens

Two vibrating screens are used to screen the materials. At this time, one vibrating screen is used for primary screening, and the other is used for fine screening, which can effectively improve the screening accuracy. However, the screening accuracy can be guaranteed by this method, but the equipment capital investment is relatively large, and the processing capacity is relatively small. Usually, when the screening accuracy can meet the needs of users, it is generally considered to use a rotary vibrating screen and a vibrating screen for screening.

3. Extend the screening time

Extend the screening time of the vibrating screen. This type of screening method is mainly used when the material is difficult to screen. By prolonging the screening time of the material on the screen surface, the longer the movement time of the material on the screen surface, the smaller particles of material passing through the screen holes. The higher the probability, the better the screening accuracy of materials can be improved. However, some improvements need to be made to the vibrating screen at this time. The common method is to install a gate on the frame of the vibrating screen and the discharge port, so that if you want to improve the screening accuracy, you can close the gate to allow more material on the screen surface. Staying for a certain time can effectively improve the screening accuracy.

4. Reduce the amount of feed

We all know that if the vibrating screen wants to achieve better screening accuracy, it usually needs to feed uniformly. The main reason is that the feeding amount is too large and the material layer of the material is too thick, so that the material on the screen surface of the vibrating screen is prone to accumulation, which is not conducive to the material passing through the screen. Similarly, for the vibrating screen, a uniform feeding method is also adopted, so as to ensure that the material is adequately screened on the screen surface, which is conducive to improving the screening accuracy. A better way is to use a vibrating feeder and other equipment to evenly feed the material , to ensure the continuity and uniformity of the material flow.

5. Add a cleaning device

In the production process, a cleaning device is added to the vibrating screen. If the cleaning device is well selected or used correctly, the screening degree of the vibrating screen can be effectively improved. The bouncing ball is a common component of vibrating screen cleaning. The bouncing ball is generally used for materials with good fluidity or slightly blocking the net. The bouncing ball is affected by the vibration force of the vibrating screen and hits the net with the material to achieve the net cleaning effect. If this kind of cleaning device does not work well for special fine powder. Especially fine materials need to use ultrasonic device. The ultrasonic device is especially used for the screening of fine materials, and the application of ultrasonic waves to the vibrating screen can effectively improve the screening accuracy. The brush is generally used with two ultrasonic waves or bouncing balls for two-layer net cleaning.

6. Reduce the moisture content of materials

For materials that are difficult to screen, it is usually due to the fact that the material contains a large amount of water, or the material has a certain viscosity and other factors. These factors affect the screening accuracy and screening effect of the vibrating screen. If you want to achieve a better screening effect, take certain measures to dry the material before feeding, so that the material will not block the screen during the screening process. What we need to explain here is that the vibrating screen cannot be used for screening materials with a large water content.

Factors affecting the screening accuracy of vibrating screen

High frequency dehydration vibrating screen

1. The size of the vibrating screen

The size of the vibrating screen is a factor that affects the screening accuracy. Different types of vibrating screens have different adaptability to the materials entering the screen, and the screening motions of materials on different types of vibrating screens are also different.

2. Feeding method

The factors affecting the screening accuracy are also the feeding method. The screening accuracy has a particularly important relationship with the quantitative feeding of the vibrating screen. The control of the feeding amount per unit time and the feeding amount during the running process of the vibrating screen is to determine the screening efficiency and screening. One of the important factors of accuracy. If the quantitative feeding cannot be controlled, the screening efficiency will generally be poor.

The above is the answer on how to improve the screening accuracy of the vibrating screen. First of all, we must clarify that the screening accuracy of the vibrating screen is not high because the screen mesh is blocked, the material moisture and viscosity are large, etc., and then take certain measures to improve the screening accuracy. For example, the vibration frequency of the vibrating screen is adjusted, and two vibrating screens are used to screen materials. In the actual production process, the vibrating screen can be adjusted appropriately according to the specific situation and production needs.

The advantages and disadvantages of commonly used sieve plates for vibrating screens and selection principles

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There are many types of vibrating screens and a wide range of applications. No matter what kind of screening equipment, the screen is an indispensable part. The sieve plate separates materials of different sizes under the action of vibration force through materials of different shapes and sizes, and material sizes, to achieve the purpose of classification.

However, the sieve plate is in direct contact with the material and will suffer a certain amount of wear from the material. Therefore, the sieve plate should have sufficient strength, high open rate and not easy to block holes.

The advantages and disadvantages of commonly used sieve plates for vibrating screens

High frequency dehydration vibrating screen

1. Polyurethane screen

The all-urethane sieve plate is welded by a flat steel frame. The frame tooling is a design difficulty. It is a new type of fine selection product. In recent years, it has gradually replaced the stainless steel sieve plate. The all-polyurethane screen is mainly suitable for grading, dewatering, screening and other places such as coal mines, iron ore, copper mines, gold mines, etc. It is a necessary part of the vibrating screen. Because the sieve plate is used under very harsh conditions, it requires corrosion resistance, abrasion resistance, and aging resistance, so the size of the sieve slot should be small enough during use.

Advantages: polyurethane has high wear resistance, high elasticity, sound absorption, shock absorption, not easy to run rough, good wear resistance, long service life, high screening quality, strong self-cleaning ability, good screen penetration performance, noise reduction, and improved operating environment. Wide application range, etc.

Disadvantages: The product dimensions are not flexible and the production cost is high.

Selection principle: dehydration, de-intermediation and de-sliming of various linear vibrating screens.

2. Woven mesh screen

The woven mesh sieve plate is woven with metal wires with bent buckles, and the shape of the sieve holes is square or rectangular. The woven mesh screen has two types: coarse holes and fine holes. Coarse-hole woven screens are made of low-carbon structural steel wire, spring steel wire and stainless steel wire. Fine mesh woven nets are generally made of low-carbon steel, brass, tin, tin-copper and stainless steel, etc., and are woven with a special weaving machine.

Advantages: light weight, high opening rate; and in the screening process, due to the elasticity of the metal wire, high-frequency vibration will cause the fine-grained materials stuck on the steel wire to fall off, thereby improving the screening efficiency. Suitable for screening of medium and fine-grained materials.

Disadvantages: shorter life span.

Arc vibrating screen

3. Stainless steel polyurethane composite screen

The stainless steel polyurethane composite sieve plate of this new technology is pressed into a wedge-shaped wire from stainless steel round wire, and is welded with the stainless steel convex support rib by the thermoplastic roller resistance welding process or the argon arc welding process. The frame is also vulcanized with polyurethane material, convex The support ribs replace the stainless steel convex wire part, and the process of welding the support ribs during assembly is also omitted. The outer frame is made according to the needs of users.

Advantages: high overall rigidity, low magnetism, sound absorption, shock absorption, not easy to run thick, easy to disassemble, especially suitable for the dehydration operation of heavy medium coal preparation plants.

Disadvantages: The production process is complex, the technology is relatively weak, and the quality is not easy to guarantee. In the drum resistance welding spin welding, the convex support ribs are easy to be welded, which affects the product quality and appearance, the production cost is high, and it is not easy to level, and the leveling effect is not satisfactory. . There are relatively few manufacturers with this process, and it is difficult to promote and apply it.

Selection principle: dehydration and de-intermediation of banana sieve.

4. Welded slotted screen

The welded seam sieve plate is a mature and old-fashioned sieve plate. It is mainly composed of stainless steel mesh sheets and stainless steel flat iron or carbon steel flat iron material frame assembly welding. The welding of stainless steel mesh sheets It is welded by a roller resistance welding machine, using rolled wedge screen strips and convex back strips of different cross-sections and the same cross-section, which are welded by resistance heat and current, which belongs to the contact resistance welding process.

Advantages: The working surface has high rigidity, narrow screen bars can be selected, high opening rate, flexible size change, and easy processing and forming.

Disadvantages: high noise, easy to run rough, not easy to disassemble, and poor surface abrasion resistance and anti-smashing performance during work.

Selection principle: dehydration, de-intermediation and de-sliming of various linear vibrating screens and slime curved screens.

5. Bar sieve plate

The bar screen is composed of a group of parallel steel bars with a certain cross-sectional shape. The bars are arranged in parallel, and the interval between the bars is the size of the mesh. The bar screen is generally used for fixed screens or heavy-duty vibrating screens, suitable for screening coarse-grained materials with a particle size greater than 50mm.

Linear vibrating screen

6. Polyurethane composite screen

Polyurethane composite sieve plate is a drum resistance welding machine that uses electrical current through the contact surface of the weldment joint and the adjacent area to generate the resistance heat energy to heat the welded metal to a local melting or high plastic state, and then use external force to weld it into a screen. The surface is assembled and processed to make it firm. On this basis, the frame is vulcanized with polyurethane material.

Advantages: Narrow screen can be selected, high opening rate, sound absorption, shock absorption, not easy to run thick, easy to disassemble and assemble.

Disadvantages: low screening rate, hole blocking, easy breakage of the screen, easy to wear, large particles of ore are easy to run out after wear, and the use value will be lost after wear or fracture, which indirectly causes high cost and inconvenient operation and maintenance. This kind of screen plate It can be produced by many domestic manufacturers in Taiyuan and Anhui, and it is easy to promote.

Selection principle: dehydration, de-intermediation and de-sliming of various linear vibrating screens and slime curved screens.

7. Punching sieve plate 

Punching screens are generally formed by punching round, square or rectangular screen holes on a steel plate with a thickness of 5-12mm. Compared with the round or square sieve plate, the rectangular sieve has a larger effective area, lighter weight, and higher productivity. It is suitable for processing materials with higher moisture content, but the separation accuracy of sieving is poor.

The above is an introduction to the advantages and disadvantages of commonly used sieve plates for vibrating screens. The sieve plate is an important working part of the vibrating screen to complete the process of screening materials. Different materials and different places should choose different sieve plates to achieve the ideal screening. Effect. Under the premise of meeting the production process indicators, choose the sieve plate that is suitable for your actual situation and cost-effective, so as to create greater economic benefits.