How to maintain linear vibrating screen in coal preparation plant

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Linear vibrating screens are usually used for de-intermediation and dewatering operations in coal preparation plants. They are mainly used for de-intermediation and dewatering operations in coal preparation plants.

There are many types of structure and transmission methods for linear vibrating screens, such as flexible connection, universal joint shaft connection, etc. The excitation methods include eccentric sliders, box-type vibration exciters, etc. The vibrating screen manufacturer mainly introduces the following detailed introduction for the routine operation and maintenance of the linear vibrating screen in the form of the current compact box-type vibration exciter.

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Main components of linear vibrating screen

1. Screen body: usually adopt ring-groove rivets to clean and seal assembly to avoid the corrosion of the bolt joint surface by wet objects. At the same time, the side panels are assembled without welding seams and rivets hydraulically to ensure that the overall structure has no residual stress.

2. Vibration beam: usually a box-shaped design, the main welds are fully penetrated, first-level UT inspection and magnetic particle inspection, and heat treatment to eliminate welding stress to ensure high strength. Before assembling, the mating surface of the excitation beam is precisely processed by CNC machine tools, which effectively guarantees the overall assembly quality of the screen.

3. Crossbeam: Usually circular special pipe design is adopted, and the main welds are all penetrated. First-level UT inspection and magnetic particle inspection are carried out, and heat treatment is carried out to eliminate welding stress and ensure strength. The surface can be treated with polyurethane spraying process to improve erosion and corrosion resistance.

4. Vibration exciter: It is composed of special vibration bearing, eccentric pendulum block, magnetic oil plug and other components, and uses splash lubrication to excite. The exciter can work normally under the temperature of -30℃~+80℃, usually with special respirator.

5. Intermediate shaft: Use an intermediate shaft to connect between the two exciters to ensure the synchronous rotation of the left and right exciters. Both ends of the intermediate shaft are connected with the pendulum block of the vibration exciter by a unique elastic rubber disc coupling. The intermediate shaft is a rigid shaft, maintenance-free and without lubrication.

6. ​​Main drive shaft: The main drive shaft is a universal joint shaft that connects the statically fixed installation drive mechanism and the dynamic vibrating screen body.

7. Drive mechanism: The drive mechanism is composed of a motor, a belt drive and a countershaft assembly. The main motor has a large starting torque and fast acceleration, so that the screen machine quickly passes through the resonance zone. The motor is installed on the rail seat to facilitate belt tensioning. The transmission mechanism adopts belt drive to adjust speed and reduce speed, transmit power, and adjust the belt tension with guide rail seat screw tension motor. The countershaft assembly is composed of a countershaft, a bearing, an adapter sleeve, a labyrinth seal and an open bearing seat.

8. Cushioning spring: steel coil spring is used for vibration isolation and cushioning between the vibrating screen body and the installation base. The spring stiffness is small, which reduces the dynamic load on the base. Rubber pads are added at both ends of the spring to reduce the friction and friction noise between the spring and the steel spring seat plate.

9. Screen surface: According to the purpose and user needs, the screen surface adopts different types of sieve plates. The main types are: continuous sieve slotted polyurethane sieve plate, polyurethane frame stainless steel slotted sieve plate, polyurethane frame stainless steel woven sieve plate, polyurethane frame stainless steel punch Hole sieve plate.

The operating procedures of the linear dewatering screen

1. Before driving, check carefully whether the sieve plate is damaged, loose, whether the eccentric shaft bolt is loose, whether there is any debris on the screen surface, whether the chute is unblocked, the water spray device is intact, and no one is working on the equipment.

2. The screen surface should be flat, free from damage or looseness, and the joints should be tight. The sieve holes and sieve slits of the deintermediation sieve should not be too large, small, or excessively worn.

3. The exciter, vibration motor and other lubrication parts should be well lubricated; the support spring should be free from damage, lack and aging failure; all safety facilities should be complete and intact, and comply with relevant regulations.

4. Try to drive without load; the sieve that needs to be sprayed with water should not be blocked, otherwise it should be cleaned immediately.

Three, the start and stop sequence of the linear dewatering screen:

Start sequence:

1. The inspection before the start of the separation screen is completed, and the shift leader or production dispatcher has been given a driving instruction to confirm that the equipment in the next process has been started and operating normally before starting the screen.

2. After the sieve is started, first turn on the water spray and confirm that it is normal before allowing the material to be fed to the screen surface. Adjust the water spray size in time according to the material on the screen surface.

After the start-up is completed, perform a comprehensive inspection and make a record of the shift.

1. You must get a parking instruction before you can stop.

2. It must be known that the equipment in the previous process has indeed been stopped.

3. Before stopping, all materials on the screen must be unloaded, and then shut down after turning off the water spray.

Operation and maintenance

1. Check the incoming materials, discharge and spray pipes regularly during operation, and report them if they are blocked.

2. Frequently monitor the eccentric shaft, whether the sound is normal, whether the sieve plate is loose, whether there is water running on the sieve surface, report and deal with it in time.

3. During operation, pay attention to check the temperature of each bearing, the temperature of the motor, the sound, the working state of the coupling and the amplitude of the screen under different loads, and report the problem in time.

4. The screen box should vibrate smoothly during operation, and there should be no abnormal swings. If the screen box shakes, check the working conditions of the four support springs and the running direction of the motor.

5. Pay attention to the working conditions of the exciter and the vibration motor during operation. The spindle should rotate flexibly and the bearing should be well lubricated; pay close attention to the bearing temperature.

6. ​​The vibrating screen should regularly check the concentration and particle size composition of the water under the screen to determine the wear of the screen. If the wear is serious, it should be replaced in time.

7. The de-intermediation vibrating screen should adjust the pressure and water volume of the water spray to ensure that the heavy medium of the product on the screen is flushed; often check (see, touch by hand) the de-intermediation effect and moisture of the product on the screen, and adjust according to the inspection result The amount of water sprayed can improve its cleaning effect; closely contact the density control driver to jointly adjust and ensure the deintermediation effect and dehydration effect of the deintermediation screen.

8. The technical indicators of de-intermediation and dewatering include: unit consumption of water spray, concentration of under-sieve and super-grain content, product on-screen and moisture. The driver should strive to complete the above-mentioned indicators stipulated by the factory.

The main measures to complete the index of removal of referral and dehydration

1. In order to strengthen the maintenance of the equipment, keep the vibrating screen in a good working condition; clean the nozzles frequently to ensure uniform spraying; strengthen the management of the screen surface and observe the dynamics during operation. After parking, check frequently, clean up frequently, fill loopholes frequently, and clear blockage frequently to ensure the effective separation (water) area of ​​the screen surface.

2. It is strictly forbidden to put the scattered coal into the funnel under the sieve; it is strictly forbidden to run without water.

3. Regularly check, adjust and replace the coupling and support spring; clean the screen surface and chute; check the tightness of the screen surface, and deal with it if it is loose.

4. Use the parking time to perform equipment maintenance, and deal with problems that occur during operation and check after parking.

5. Do a good job in equipment and environmental sanitation, fill out the work log as required, and do a good job of shifting shifts.

What should I do if the linear vibrating screen fails?

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In daily use, the linear vibrating screen will inevitably be damaged. As a professional vibrating screen manufacturer, Hiside gave us the following detailed introduction to the common faults and solutions of linear vibrating screens. Let’s take a look.

The linear vibrating screen is driven by double vibration exciters. When the two vibration exciters are synchronized and rotated in opposite directions, the excitation force generated by the eccentric block cancels each other in the direction parallel to the motor axis, and in the direction perpendicular to the motor axis. Stacking is a resultant force, so the trajectory of the screen is a straight line. The two motor shafts have an inclination angle relative to the screen surface. Under the combined force of the exciting force and the material’s self-gravity, the materials are thrown up and jump forward on the screen surface for linear motion, so as to achieve the purpose of screening and grading materials. Can be used to realize automated operations in the assembly line. It has the characteristics of low energy consumption, high efficiency, simple structure, easy maintenance, and fully enclosed structure without dust spillage. The high screening mesh is 400 meshes, which can screen out 7 kinds of materials with different particle sizes.

Arc vibrating screen

1. The pipe beam is broken

If the wall of the pipe beam is too thin, it may cause breakage. At this time, the thick-walled pipe of the same model or the larger one should be used. But it should not be too large or thick, because this will increase the vibration quality of the sieve and cause many problems; the joints of each sieve plate of the dewatering and de-intermediation screen must have horizontal and vertical beading. If there is no longitudinal beading, water The pipe beam will leak from the gap between the screens and the pipe beam will easily break at the scouring point; the wider the screen, the easier the pipe beam will break. According to experience, when the screen width exceeds 3m, use dual channels.

2. The beam is broken

The beam fracture is mostly due to the long working time at the critical frequency, the loosening of a large number of high-strength bolts that fasten the side plates, and the serious deformation of the spring makes the left and right heights vary greatly. It is also possible that the weight error of the eccentric block is too large, causing damage to the structural parts. The beam is broken. At this time, the damaged structural parts and beams should be replaced, the bolts should be tightened, and the quality of the eccentric block should be adjusted.

3. The screen frame is broken

The screen frame is prone to fracture due to shaking. The best way to solve this problem is to thicken the side plate or add additional plates to the local area of ​​the side plate near the exciter to enhance the rigidity of the entire screen frame.

4. The discharge port is broken

Since vibrating screens are generally manufactured non-standard, the sizes required by customers are different. Some require the discharge port to be extended forward or downward. In this way, the discharge port will be relatively more likely to break. If it is the first design, the plate thickness or ribs can be strengthened. If it breaks accidentally, check the material quality. Also check whether the parameters of the vibrating screen are correct. Furthermore, during the feeding process, avoid excessive feeding of the vibrating screen at one time. The screen can be basically fully utilized. The excessive feeding amount not only affects the screening effect, but also the screened material cannot be discharged through the screen in time. Excessive weight backlog will also cause the break of the vibrating screen’s discharge port.

If the linear vibrating screen fails, you can refer to the above methods to solve it, but if your problem has not been solved, please contact the manufacturer for after-sales service, and ask professionals to repair it in time to avoid reducing your work efficiency.

 

How to improve the screening effect of mine vibrating screen?

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In the concentrator, the vibrating screen is one of the commonly used grading equipment. The screening effect of the vibrating screen is of great significance to the follow-up operation. Therefore, how to improve the screening effect of the vibrating screen is a problem that needs to be considered. Analyze what factors affect the screening effect and how to improve the screening effect of the vibrating screen by changing these factors.

As a professional vibrating screen manufacturer, Hiside introduced many factors that affect the screening effect of mine vibrating screens. Three of the more important factors are the characteristics of the material entering the screen, the screen surface parameters of the vibrating screen, and the motion parameters of the vibrating screen. Below, our vibrating screen manufacturer will analyze these three factors one by one and discuss how to improve the effect of mine vibrating screens by changing these factors.

1. The characteristics of the material being screened

Different materials have different characteristics of their own, with differences in density, hardness, and water content. Generally speaking, the screening effect of materials with higher hardness and better brittleness is better than materials with lower hardness and poor brittleness. For the materials that enter the screen, there are two aspects that can directly affect the screening effect: the particle size of the material and the water content of the material.

When the particle size of the material is close to the mesh size, the screening efficiency will be significantly reduced. These particles may block the mesh and reduce the screening area. This is a common phenomenon in the closed-circuit crushing process. This situation can be improved by increasing the vibrating screen. The amplitude can be improved. The increase of the amplitude can promote the fine-grained material to pass through the screen surface and reduce the occurrence of clogging. In addition, it can increase the pass rate of the middle part of the screen to improve the screening effect. It can also be improved by changing the feeding method The utilization rate of the screen surface of the vibrating screen can be multi-channel feeding, which reduces the time and distance of the material on the screen moving on the screen surface and improves the screening effect.

When the material has a large water content, the material is prone to adhesion, which reduces the screening efficiency. Generally speaking, the wet material with a large water content can be improved by increasing the screen hole. However, if the material contains mud ,when the amount is greater than 8%, wet screening or pre-washing methods should be used for treatment.

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2. Vibrating screen surface parameters

The screen surface parameters of the vibrating screen include the shape of the vibrating screen mesh, the opening rate of the vibrating screen surface, the material of the screen surface and so on. Generally speaking, a long screen surface has a long material residence time, more chances to penetrate the screen, and high efficiency, while a wide screen surface has better processing capacity. Practice has proved that the appropriate ratio of screen surface aspect ratio is 2:1~3:1.

The opening rate of the screen surface of the vibrating screen here refers to the screening area of ​​the vibrating screen, which is the ratio of the screen area to the total area of ​​the screen surface. The larger the screen area, the higher the productivity per screen surface and the higher the screening efficiency. As for the shape of the sieve holes, the choice is made according to the particle shape of the material. Generally, it is better to use square sieve holes for sieving round particles.

In terms of materials, different screen surface materials will also have an impact on the screening effect, which can directly affect the adhesion coefficient of minerals and screens. For viscous minerals, rubber and polyurethane should be used for screen materials with greater elasticity. Ensure that the material on the screen is loose. However, this type of material usually has the disadvantage of a small open porosity.

After combining the above aspects, we can know that when selecting the vibrating screen surface, different materials and opening rates should be considered comprehensively.

3. Motion parameters of vibrating screen

The motion parameters of the vibrating screen include two factors: the vibration frequency of the vibrating screen and the direction angle of the vibrating screen. Vibration enables the material on the screen surface to be thrown away from the screen surface, so that the coarse material reaches the upper layer of the material layer, and the fine material reaches the lower layer of the material layer, close to the screen surface, the screen layer is evenly distributed, and the passing rate of fine materials increases accordingly. For materials with large particle size, generally the higher the frequency, the higher the number of bounces on the screen surface, the increased chance of contact between the material and the screen surface, and the reduction of the occurrence of clogging of the screen holes. Therefore, an appropriate increase in the vibration frequency can effectively improve the screening effect.

The vibration direction angle is the angle between the vibration direction line and the screen surface. The larger the value of this angle, the smaller the horizontal movement distance of the material during the screening process, and the lower the movement speed on the screen. It is obtained through practice. For materials that are easy to screen, the direction angle should be small, and for materials that are difficult to screen, the direction angle should be large. In general, the direction angle of the linear vibrating screen is between 30 degrees and 60 degrees, and the direction angle of the circular vibrating screen is 90 degrees.

After the above analysis, we understand some of the factors that affect the screening effect of the mine vibrating screen and how to improve the efficiency of the vibrating screen. In short, we must choose the vibrating screen according to the actual needs, and choose the appropriate screen surface material as much as possible to improve the motor adjustment excitation. Vibration force, and try to ensure the lower water content of the material, and improve the screening effect under the premise of ensuring the processing capacity.