A slime centrifuge is a machine that uses centrifugal force to separate components from a mixture of liquid and solid particles or a mixture of liquid and liquid. Mainly used to separate solid particles and liquids in suspension; or to separate two incompatible liquids in emulsions with different densities; can also be used to remove liquids in wet solids; especially ultra-high-speed tube separators can also separate different densities using the different sedimentation velocities of solid particles of different densities or particle sizes in the liquid, some decanter centrifuges can also classify solid particles according to density or particle size.

Its working characteristics are as follows:

1. Centrifugal dehydration: The process of separating liquids and solids by centrifugal force. Two different principles can be used: centrifugal filtration and centrifugal sedimentation.

2. Centrifugal filtration: the processed rotating material is added to the surface of the rotating cone sieve. Under the action of centrifugal force, the solid adheres to the surface of the screen and rotates with the rotor, and the liquid is discharged through the material gap and the screen gap. Dehydrate clean coal.

3. Centrifugal sedimentation: Add coal slime water to a simple rotor, under the action of centrifugal force, the solid settles in the liquid, and the sediment is further squeezed out of the water by centrifugal force, which is mainly used for the dehydration of coal slime.

4. Centrifugal strength: used to indicate the size of the centrifugal force on the material, that is, the ratio of the centrifugal force to the gravity on the material. Centrifugal strength is proportional to the square of the rotor radius and speed.

The above are the working characteristics of the centrifuge. Coal, as an important part of traditional energy, provides a huge impetus for the operation of today’s society. Using advanced machines to better screen out high-quality media can greatly improve the efficiency of daily production.

Linear vibrating screen is one of the main equipment for crushing and screening, and it is also the key equipment to provide qualified materials for subsequent operations. Its screening efficiency directly affects subsequent operations. In the actual dressing plant, the main factors affecting the screening efficiency of the linear vibrating screen include: material properties, screen surface structural parameters, vibration characteristic parameters and so on. Next, the vibrating screen manufacturer will specifically analyze how the above aspects affect the screening effect of the linear vibrating screen.

Material properties

The nature of the selected material is one of the main factors affecting the screening efficiency of the linear vibrating screen, and its material properties are mainly reflected in the loose density of the material, the particle size of the material, and the shape of the material.

1. Loose density of selected materials

Generally, the loose density of the material is large and the bulk particles are easy to pass through the screen, and the screening efficiency is high. The effective screening area of ​​the sieve is reduced, which in turn affects the screening efficiency. In order to ensure the screening efficiency, it is necessary to control the bulk density of the selected materials.

2. Selected material particle size

The particle size of the selected material is also an important factor affecting the screening efficiency of the linear vibrating screen. The particle size of the material entering the sieve should meet the size of the sieve hole. Small particles are easy to sieve, and large particles are not easy to sieve. To ensure the screening efficiency, it should be strictly controlled. Into the sieve material particle size.

3. The shape of the material entering the sieve

The shape of the material entering the sieve will affect the sieving performance. Generally, the particles are fully ground and are easier to sieve than the mineral particles of the specification. The sieving rate of materials with irregular particle shapes such as long strips and flakes is poor. Therefore, it is necessary to ensure that the particle shape of the crushed material conforms to the sieve hole standard.

Screen structure parameters

The structural parameters of the linear vibrating screen are mainly reflected in the length and width of the screen surface and the size and shape of the screen hole.

1. Length and width of screen surface

The length of the screen surface of the linear vibrating screen mainly affects the screening efficiency, and the width of the screen surface mainly affects the productivity. The sieve surface of the linear screen is longer, the residence time of the material on the sieve surface is longer, and there are more opportunities to pass through the screen, which will improve the screening efficiency. In fact, the width of the screen surface has different effects on the screening efficiency and the length of the screen surface on the screening capacity.

The relationship between the screening efficiency and the time that the material experiences on the entire screen surface is: at the beginning, the probability of passing through the screen is high. Because there are more fine-grained materials on the sieve surface at the beginning, the probability of sieving per unit time is high. After a certain period of time, the particle size of the materials left on the sieve surface is mostly difficult-to-screen materials close to the size of the sieve holes. Even if the material stays on the screen surface for a long time (that is, the length of the screen surface is large), it is difficult to increase the probability of the material passing through the screen, resulting in a decrease in the working efficiency of the screen machine. Therefore, selecting the appropriate screen surface length can effectively improve the screening efficiency. Generally, the aspect ratio of the linear screen screen surface is 1:2~1:3.

2. Screen shape and size

The selection of the shape of the sieve hole of the linear vibrating screen mainly depends on the sieving particle size of the material entering the sieve and the use of the product under the sieve. Compared with the sieve holes of other shapes, for the same material, the round sieve hole is sieved through the round sieve hole. The particle size of the material is smaller, and the size of the material sieved by the rectangular sieve is larger. Therefore, in order to obtain higher screening efficiency, different sieve shapes must be selected for different screening materials.

Vibration characteristic parameters

The vibration characteristic parameters of linear vibrating screen include screen surface inclination angle, vibration direction angle, amplitude and vibration frequency.

1. The inclination of the screen surface

The size of the inclination angle of the screen surface of the linear vibrating screen is related to the processing capacity of the equipment and the screening efficiency. When the inclination angle of the screen surface increases, the throwing strength of the material on the screen will increase, and the moving speed of the material on the screen surface will increase, increasing the vibrating screen. However, the residence time of the material on the screen is short, the chance of the material being screened is less, and the screening efficiency is reduced. On the contrary, the processing capacity will be reduced, and the screening efficiency will be high.

In order to control the screening efficiency of the vibrating screen within an ideal range, the inclination angle of the screen surface of the linear vibrating screen is generally between 0 and 8°.

2. Vibration direction angle

The angle between the vibration direction and the upper screen surface is called the vibration direction angle. The larger the vibration direction angle is, the shorter the distance that the mineral particles move in each throwing motion, the slower the advancing speed on the screen surface, and the more sufficient the material is to be screened, so the screening efficiency is higher. The smaller the vibration direction angle is, the longer the material travels on the screen surface when thrown, and the shorter the time to pass through the screen surface, so that the material cannot be sufficiently screened, so the screening efficiency is low. In order to ensure the screening efficiency of the linear vibrating screen, the value range of the vibration direction angle is preferably 30-60°.

3. Amplitude

The magnitude of the amplitude of the linear vibrating screen determines the energy of the material particles moving on the screen surface. , the screening efficiency is better; otherwise, the screening efficiency is poor. Generally, the selection of the amplitude is determined according to the particle size and properties of the material to be screened. For materials with larger particle size, it is suitable to use a linear sieve with larger amplitude and lower frequency; for materials with finer particle size, it is easy to use a linear sieve with smaller amplitude and higher frequency.

4. Vibration frequency

The vibration frequency of the screen surface of the linear vibrating screen mainly affects the movement state of the mineral particles. Too low or too high frequency is not conducive to the material passing through the screen holes. If the vibration frequency is too low, the movement probability of mineral particles in the direction of the vertical screen surface is small, and the screen penetration rate is low; if the vibration frequency is too high, the vibration of mineral particles is easy to be chaotic, which affects the screening efficiency. Generally, the vibration frequency range of the screen surface of the linear vibrating screen should be controlled within 15Hz~30Hz.

The above are the major aspects that affect the screening efficiency of the linear vibrating screen. If you want to effectively improve the screening efficiency of the linear vibrating screen, these major aspects cannot be ignored!

In the actual dressing plant, each mineral has its own mineral characteristics, and there are differences in density, hardness, gangue content, etc. Therefore, when selecting equipment, a mineral processing test should be carried out first, and a suitable linear vibration should be selected based on the test results. sieve, so as to ensure that the parameters of the equipment are in line with the mineral particles.

Mining vibrating screen is a kind of large-scale screening equipment, commonly used in the mining industry, etc. The use of this vibrating screen to screen materials generally requires relatively large output. In use, we also hope that the larger the output of the equipment, the better. Since the models and specifications produced by each vibrating screen manufacturer are different, the output of each equipment is also different, but this can be improved by some methods, so how to increase the output of the vibrating screen?

The method of increasing the output of vibrating screen

1. Improve the opening rate of the screen mesh

Because the ore is relatively large in mesh, a metal woven mesh or punching plate with a large aperture is generally used. If you want to increase the output, you can also replace the screen mesh with a larger aperture than the previous one for production. The high opening ratio is beneficial to improve the screening effect; but the disadvantage is that it is not as high as the previous screening. Therefore, once the output needs to be increased, it will inevitably affect the screening accuracy.

2. Adjust the feeding method

A distribution device can be installed at the feed port of the linear vibrating screen, so that the material can be evenly fed to the screen surface to achieve the requirement of increasing the output, which is of great help to improve the screening output of the linear screen. If the distributor is added unconditionally, attention should be paid to manual feeding to ensure uniform feeding. When feeding, the cloth should be evenly distributed.

3. Increase the screening area

The screening area of ​​the linear vibrating screen can be achieved by increasing the length and width of the screen surface. The width of the screen surface determines the processing capacity of the sieve. The wider the screen surface, the greater the output; the length of the screen surface determines the screening efficiency. The longer the screen surface, the longer the material screening time, and the higher the efficiency. After the size is reduced, the sieving efficiency improves little or not at all. At this time, increasing the length of the sieve surface will only increase the volume and weight of the sieve.

4. Adjust the inclination of the screen surface

Adjusting the angle of the screen surface is also an important method to increase production. The larger the inclination angle of the screen surface, the faster the material layer moves forward on the screen surface, and the larger the output, but the time for the material to stay on the screen surface is shortened, which reduces the chance of particles passing through the screen and reduces the screening efficiency. The inclination angle is 45°. If the screened material is not high in accuracy and only needs to be screened roughly, the height of the vibration spring under the lower base and the screen body can be adjusted appropriately. This angle is generally controlled at ≥10°, so that the height of the feeding port can be adjusted. The rise can speed up the movement of the material on the screen surface to increase the output. It should be noted that if you continue to increase the height, the screening effect will not be achieved.

5. Increase the excitation force of the motor

The strength of the motor’s exciting force directly affects the screening effect. The greater the exciting force, the greater the screening output. It should be noted that the linear vibrating screen is a double motor. The use time should pay attention to the adjustment of the motor’s exciting force on both sides. equal.

6. Install the net cleaning device

The bouncing ball is installed between the screen and the punching plate to continuously bounce up and down to hit the screen, so that the ore stuck and stuck between the screen holes is bounced and dropped by the impact to achieve the effect of effective net cleaning. Through the cleaning method, the material can quickly pass through the screen, so as to achieve the purpose of screening, effectively improve the screening rate of the material screened by the mining vibrating screen, and increase the output of the mining vibrating screen.

7. Adjust the inclination angle of the screen machine

The design inclination angle of the mining vibrating screen is usually 45°, but in the actual use process, if there are few impurities in the material, only a coarse screen is required, and the user can appropriately adjust the height of the vibration spring at the lower part of the feeding port to make the feeding The increase of the mouth height can speed up the movement of the material on the screen surface and increase the output.

8. Screen surface management

The vibrating screen will cause certain damage or even corrosion to the linear screen due to the residual materials on the screen surface and the screen body, which will reduce the life of the machine and reduce the output. Therefore, when the machine operation is completed, the materials on the screen surface should be completely screened. Clean and then turn off the power, stop working.

9. Regular maintenance of vibrating screen

The materials screened by the mining vibrating screen are very rough, so the material itself will be difficult to handle, so the material may block the screen or remain in the screen box during shutdown, and the long-term residue will also reduce the durability of the vibrating screen. Therefore, in a certain sense, regular maintenance of the vibrating screen can also increase the output.

Reasons for the low output of vibrating screen

1. Uneven force on the screen surface

1) Uneven feeding. In the process of ore mining vibrating screening, if the feeding is uneven, the ore distribution on the screen surface will be uneven; if the feeding is too much, the screen material will be too thick, one screen will be seriously overloaded, and the other screen will be almost No-load operation and load production, resulting in blockage of the screen will lead to a decrease in production, and will often cause uneven wear and tear of the screen and rapid damage.

(2) The force on the screen surface is too large. The distance between the funnel and the feeding end of the circular vibrating screen is too high, reaching 400 mm. When the ore enters the circular vibrating screen from the funnel, the impact force on the feeding place is too large, resulting in the fracture of the girder at the feeding place and the cracking of the box; the ore enters the circular vibrating screen. After the vibrating screen enters the material end, the distribution is uneven, the ore always runs to one side, and only half of the screen meshes play the role of screening, resulting in serious ore accumulation on one side and low screening efficiency.

2. The material stays for too long

The ore and other logistics move slowly on the screen, and the screen surface accumulates too much ore, reaching a thickness of 200mm. Through multiple measurements of the moving speed of the material on the screen surface, the speed is about 0.2m/s. The moving speed of the ore is too slow, resulting in too much ore on the screen surface, so that the vibrating screen always runs in an overloaded state. It affects the screening accuracy and yield.

Factors affecting the output of vibrating screen

1. Particle and sieve shape

The meshes of the material particles and the supporting screen of the vibrating screen should be compatible with each other. For example, the spherical particles mostly use circular screen holes, while in the feed industry, for the cylindrical or irregular particles, there are both circular and rectangular. The sieve hole, the state of the material particles when they contact the sieve hole has a great influence on whether the particles can pass through. Whether the material can pass through the screen smoothly has some chance. It can be concluded by statistical means that the material with cylindrical particles in actual production generally uses rectangular meshes, while for irregular particles, circular meshes are mostly used.

2. The opening rate of the screen mesh

The opening rate of the screen will affect the output of the vibrating screen. The opening rate of stainless steel woven mesh is large and the strength of the mesh can be used normally. It is also widely used in practical applications.

3. Materials placed on the screen surface

If the material is thickly stacked on the screen surface, the material on the upper layer will be discharged from the upper discharge port before it can pass through the screen, which will lead to the loss of net raw materials, and mixing will occur in the screening and grading operations. material phenomenon, affecting the quality of the finished product. Of course, the material layer cannot be too thin, otherwise the output will be relatively small. According to the test, the appropriate material layer thickness is obtained, and an average value is obtained between the inclination angle of the screen surface and the amplitude of the screen body.

The above is the answer to how to improve the output of the vibrating screen. You can improve the output of the vibrating screen in a targeted manner according to the method analyzed by the editor above and combined with your own situation. More importantly, after the vibrating screen is used, it is necessary to maintain and maintain the vibrating screen, which is of great benefit to the stable production of the vibrating screen.

The vibrating screen is a screening equipment often used in the sand and gravel industry. It uses the exciting force generated by the exciter to screen the material, which is convenient for the next production of the material. However, the vibrating screen does not run continuously for 24 hours. When the production is not in use, the vibrating screen equipment must be shut down. Sometimes when it is restarted, it may be difficult to start. Then when the vibrating screen starts What about difficulties?

Reasons for the difficulty in starting the vibrating screen

1. The exciter is faulty

The common reason for the difficulty in starting the vibrating screen is the failure of the vibrating screen. When the vibration exciter parts are working, it is necessary to ensure a good lubrication state, not only high-efficiency lubricating grease, but also preventing the lubricating grease from thickening, solidifying, and agglomerating, so as to play its due lubricating function.

Solution: Check the lubrication of the exciter and replace the appropriate lubricating oil.

2. Power failure

Check if the power supply is faulty, and then check the current of the motor. If the motor is faulty, you need to replace the new motor components; the assembly line of the vibrating screen is composed of centralized control circuits. When some components are damaged, it must be timely. Replace with new components; sometimes the voltage is unstable, and the voltage at startup is lower than the rated voltage, which is prone to failure.

Solution: replace the new motor parts; ensure the voltage stability during the working process of the vibrating screen.

3. The vibrating screen itself is faulty

Once again, the linear vibrating screen equipment itself has malfunctioned. Due to the large change in the supply flow of the material, the feeding amount of the linear vibrating screen exceeds the specified feeding value, causing the material to form a blockage on the screen surface. When the material accumulates to a certain amount. , The working load of the linear vibrating screen is large, which makes it impossible to start normally.

Solution: Clean up the materials on the screen surface to ensure that the screen surface can screen the materials smoothly.

Precautions before starting the vibrating screen

1. Before starting the vibrating screen, check whether the screws and locking parts are firm and whether there is looseness.

2. Check whether the screen of the vibrating screen is pressed tightly, and whether the connection between the motor, rubber pad, screen body and frame is in good condition.

3. Check whether the power supply voltage of the vibrating screen is stable.

4. Check the vibration motor of the vibrating screen, remove the end cover of the motor, check whether the fan-shaped block and the relative angle of the motor are consistent, and check whether the installation angles of the two motors are consistent.

5. Check the feeding device of the vibrating screen; check the tightening gate of the vibrating screen; check the connection between the motor and the screen body.

6. Check whether the inlet and outlet hoses of the vibrating screen are sealed and connected, and do not overtighten them, otherwise they will be twisted when the screen body moves.

7. Carry out no-load test run on the vibrating screen. During the test run, the reciprocating linear motion is performed, the screen body and the frame have no collision phenomenon, and there are no abnormal phenomena such as abnormal noise and abnormal trajectory movement during the operation. After 10-15 minutes, use a wrench to tighten the bolts used for the drive mechanism.

8. The installation angles of the two motors should be consistent.

In summary, if you want to know what to do if the vibrating screen is difficult to start, first find out the reason for the difficulty in starting, mainly because there are some faults in the exciter, power supply or the vibrating screen itself. For example, the exciter may be due to improper lubrication, so It is necessary to check the lubrication and replace the appropriate lubricant. In addition, the operator should always pay attention when operating to ensure the normal production of the vibrating screen.

In mining and other industries, it is necessary to use vibrating screen to screen materials. When the vibrating screen is used, it has a strong exciting force, and the material is also screened because of this exciting force. After using the vibrating screen for a period of time, the screen machine may have a problem of large beating. If the beating is serious, it may cause the side plate to break. Therefore, when this phenomenon is found, it should be solved immediately, but the first thing is to analyze the cause.

The reason for the large vibration of the vibrating screen

1. The damping spring has high hardness
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If the hardness of the vibration damping spring is too large, it may not be able to achieve the effect of buffering, so the vibration screen will have a problem of large beating when it is running. Because the function of the damping spring is to connect the screen base and the screen frame, and it can also play a buffering role. Therefore, the hardness of the damping spring should not be too large.

2. Bearing radial clearance problem

If the radial clearance of the vibrating screen bearing is too small or too large, the bearing system will generate large vibration, and the whole vibrating screen machine will show a large beating phenomenon. When the radial clearance is too small, it will cause high frequency vibration; when the radial clearance is too large, it will cause low frequency vibration. If the radial clearance is too large, the radial natural frequency of the bearing elastic system will be reduced, resonance will easily occur, and large low-frequency vibration will be generated.

The main reason is that a large acceleration occurs at the impact point of the rolling element and the ferrule. In the early stage of the shock, a high-frequency compression wave irrelevant to the mass of the equipment and the shape of the object is generated and transmitted to the inside of the metal; while in the later stage of the shock, a mechanical vibration with a lower frequency than the shock compression wave is generated by the mechanical force. Therefore, the radial clearance is large, which increases the vibration of the bearing in the passband.

3. Exciting force is too strong

The vibration motor of the vibrating screen provides exciting force to the equipment during operation. If the motor power and model do not match, it may cause large jump or displacement during use. In order to increase the screening output or accuracy, some customers may adjust the motor excitation force to exceed the rated range, which may also cause the vibrating screen to vibrate violently.

4. The outer ring and the supporting hole are too tight

The cooperation between the outer ring and the support hole will affect the transmission of vibration of the vibrating screen. If the fit is relatively tight, it will force the raceway to deform and increase the shape error, resulting in an increase in vibration and a large jump. A looser fit can hinder the oil film in the gap. When the material properties of the outer ring and the bearing hole of the bearing seat are quite different, especially if the rubber damping ring is placed between them, the vibration transmission will be suppressed.

5. Improper installation of screen machine

When installing the vibrating screen, if the ground is uneven or improperly installed, it may cause excessive vibration, which will cause the vibrating screen to jump greatly.

6. Motor steering is inconsistent

The vibrating screen with double vibrating motor will adjust the steering of the motor when it leaves the factory, but when the motor is worn or damaged, if the motor rotation or power is inconsistent when the user replaces the motor, it may cause the vibrating screen machine to vibrate violently.

7. Loose anchor bolts

If there is abnormal vibration caused by uneven ground, it is necessary to check whether the anchor bolts are loose. Under the action of vibration, the long-term work of the vibrating screen will loosen the anchor bolts of the fixed base, which will cause the vibrating screen to vibrate too much during operation.

The solution to the large vibration of the vibrating screen

1. Users can solve the problem caused by excessive spring hardness by choosing high-quality springs.

2. If the user wants to adjust the exciting force, it needs to be adjusted within the range that the motor can bear. You can consult the manufacturer, or ask the technicians to purchase a model that is reasonable based on the properties of the materials provided, screening requirements, and output requirements.

3. When installing the vibrating screen, it should be noted that it needs to be installed according to the steps, and preparations should be made before installation, then install the support or hanging device, connect the screen box to it, and then install the motor and triangle tape to fix the screen surface. Note that debugging work is required to enter normal operation.

4. When the motor steering is inconsistent, it is necessary to consult a technician to re-adjust and install the vibration motor steering or eccentric block.

5. If the vibration screen jumps greatly due to the loosening of the anchor bolts, it is only necessary to tighten the anchor bolts.

The above is the introduction of the reasons for the large vibration of the vibrating screen and the solutions. There are seven main reasons for the large vibration, such as high hardness of the vibration damping spring, too small or too large radial clearance of the bearing, too strong excitation force, Loose bolts, etc., need to be solved according to the cause. For example, if the anchor bolts are loose, the anchor bolts need to be tightened.