Vibrating screen screening quality is poor, abnormal sound, serious wear and other issues to help you solve

Guide

There are many classification methods for vibrating screens (refer to the following figure). We often use electromagnetic vibrating screens, circular vibrating screens, linear vibrating screens, etc. The latter two are inertial vibrating screens, which is the vibrating screen we are used to. In daily production, vibrating screens can encounter various problems, such as poor screening quality, overheating of bearings, abnormal sounds, and incorrect technical specifications.

1 screening quality is poor

There are many factors affecting the screening effect, including the nature of the material, equipment factors, and operational factors. The reasons for the poor screening quality are: screen hole blockage, screen hole wear, screen feed unevenness, excessive material on the screen, and insufficient screen angle.

1) Screen hole blocking

When the mud content and water content in the feed are high, the material will stick to the mesh hole and block the mesh hole. At this point, the sieve hole should be cleaned first, and then the water spray volume and the screen inclination angle should be appropriately adjusted.

2) The screen hole is seriously worn

When the screen is used for a long time, the screen hole is seriously worn and the screening effect is seriously affected. At this point, the worn screen holes should be repaired. When the wear is very serious, the screen should be considered for replacement.

3) Uneven feeding of the sieve

When the feed trough of the sieve is too narrow, the material cannot be evenly distributed along the entire sieve surface, so that the sieve surface cannot be effectively utilized, and the screening effect is affected. At this point, the width of the feed chute should be adjusted to make the feed of the sieve uniform.

4) The material on the sieve is too thick

The excessive thickness of the material on the sieve may be caused by the increase of the feed amount, the obstruction of the sieve hole, and the small inclination of the sieve surface. At this time, it should be adjusted according to the specific circumstances.

5) The screen surface angle is not enough

For a circular vibrating screen, the most common reason for the poor screening effect is that the angle of inclination of the screen surface is not sufficient, and it is necessary to raise the rear support seat. In practical applications, the inclination angle of the screen surface is suitable at 20°. Generally, the inclination angle of the circular vibrating screen is selected from 16 to 20°. If the inclination angle is lower than 16°, the phenomenon that the screen is not smooth or the material is rolled upwards may occur. .

6) The eccentric block movement direction is not in the same phase

For linear vibrating screens and high-frequency vibrating screens, the poor screening quality may be related to the direction of motion of the eccentric block, because two sets of eccentric blocks of the same mass are required for self-synchronous reverse rotation, and a single direction of vibration is generated at each moment. The exciting force at a fixed angle with the horizontal direction causes the screen box to reciprocate linearly. If they are not in the same phase, the direction of the exciting force does not overlap with the direction of vibration, and the effect of efficient screening is not achieved.

2 bearing overheating

Under normal circumstances, the vibrating screen empty car test 4h, the bearing temperature should be maintained at 35 ~ 60 ° C, if the bearing temperature is high during the test run, there may be the following reasons:

1) Bearing radial clearance is too small

Since the bearing on the vibrating screen carries a large load, the frequency is high, and the load is always variable, the bearing must have a large clearance. If a bearing with a normal clearance is used, the outer ring of the bearing must be ground again to make it a large clearance.

2) The bearing gland is too tight

There must be a certain gap between the gland and the outer ring of the bearing to ensure normal heat dissipation and a certain axial turbulence of the bearing. This gap can be adjusted by a gasket between the end cap and the bearing housing.

3) Bearings lack oil or too much, oil pollution or oil quality does not match

At this time, the bearings need to be oiled, cleaned, replaced with oil and seals, checked for oil quality and oil filling, and there may be bearing wear or bearing quality problems.

3 The sound of the sieve is abnormal when it is running.

The reason why the sound is abnormal during the operation of the sieve is that the spring is damaged, the bearing is worn, the bolt of the fixed bearing is loose, and the screen is not tightened.

1) Spring damage

If the spring is damaged, it will cause a lot of noise. In this case, the spring should be replaced in time to prevent production accidents.

2) Bearing wear

When the bearing wears seriously, large noise will be generated. In this case, the bearing should be stopped and replaced in time.

3) Loose bolts for fixed bearings

If the bolt of the fixed bearing is loose, the sound will be abnormal when the sieve is running. In this case, the bolt should be tightened in time.

4) The screen is not tightened

When the screen is not tightened, the sound will be abnormal when the sieve is running, and the screening effect of the sieve will be affected. At this time, the screen should be tightened in time.

4The technical indicators of the sieve operation do not meet the requirements.

The technical indicators for the operation of the sieve include the rotational speed of the sieve, the vibration force, and the amplitude frequency. Common types of faults are: the sieve cannot be started or the amplitude is too small, the rotation speed is not enough, the vibration force is weak, and the four-point amplitude is inconsistent.

1) The sieve cannot be started or the amplitude is too small

When the vibrating screen cannot be started or the amplitude is too small, first consider whether there is electrical fault. Damage to the motor, insufficient voltage, etc. can cause malfunctions. When there is no problem in the above aspects, we will start from the mechanical aspect. Whether the sieve surface material is seriously accumulated, if it is, it should be removed in time; if the coupling bolt on the vibration exciter is detached and the grease is agglomerated, if it is, the bolt should be tightened in time to replace the grease.

2) The sieve speed is not enough

Insufficient speed may be an electrical cause. At this time, the cause should be found and handled in time. It may also be that the transmission tape is too loose. At this time, the transmission tape should be tensioned.

3) The vibration of the sieve is weak

The reason why the vibration force is weak may be that the weight on the flywheel is incorrect or too light, and the weight on the flywheel should be adjusted at this time.

4) Sieve four-point amplitude is inconsistent

The inconsistent amplitude of the four points of the sieve may be caused by the unsynchronized operation of two exciters on the same axis or material segregation. At this time, it should be adjusted so that the two exciters work synchronously, and the segregation of materials is eliminated in time.

5The parts of the sieve are seriously worn or damaged.

Some parts of the sieve will wear out and even break and damage after a long time. Common faults include tube beam breakage, beam breakage, and screen frame breakage.

1) Tube beam fracture

a) If the wall of the tube beam is too thin, it may cause breakage. In this case, the same type of thick-walled tube or the larger type of tube beam should be used, but it should not be too large or too thick, because it will increase the quality of the sieve and cause many problems.

b) The joints of the screens of the dewatering and descreening screen shall have transverse and longitudinal beading. If there is no longitudinal stripping, the water will leak from the gap between the screens and flush the tube beam. The tube beam is easy to be washed. fracture;

c) The wider the sieve, the more easily the tube beam breaks. According to the experience, when the screen width exceeds 3 m, it is better to use two channels;

d) If the pipe beam is not severely broken, in order not to affect the production, the pipe beam may be repaired and welded to continue to use. When repairing, the weld is to be along the longitudinal direction of the pipe beam, and no transverse weld is allowed. Otherwise, the pipe beam It is easier to break from the transverse weld.

2) Beam breakage

The beam breakage is mostly due to the working time at the critical frequency is too long, the high-strength bolts of a large number of fastening side plates are slack, and the springs are severely deformed, so that the difference between the left and right heights is extremely large, and the weight error of the eccentric mass may be too large, causing damage to the structural parts. The beam is broken. At this time, the damaged structural parts and beams should be replaced, and the bolts should be tightened to adjust the quality of the eccentric block.

3) Screen frame breakage

The screen frame is prone to breakage due to tremor. The best way to solve this problem is to thicken the side panels or add attachment to the local area of ​​the side panels near the exciter to enhance the rigidity of the entire screen frame.