The linear vibrating screen in the coal preparation plant has malfunctions such as excessive vibration of the screen box, overheating of the bearing, abnormal sound, etc., which seriously reduce the productivity of the coal processing plant. Here are some common problems that may occur on your vibration screens and ways on how to troubleshoot or fix them.
The side plates crack
The amplitude of the vibrating screen box is inconsistent, resulting in concentrated stress and cracking the side plates or sidewalls. The main reasons are:
① The fact that the elevation difference between the vibrating screen springs on both sides of the vibrating screen is too large will lead to the inconsistent amplitude of the screen box.
Vibrating screen troubleshooting: Install springs in strict accordance with the installation standards; replace damaged or failed springs in time.
② Improper welding between side plates, reinforcing plates, and wing plates causes welding stress.
When the vibrating screen is working, the vibrating screen exciter generates a high-frequency excitation force. Under the action of the welding stress and the excitation force, the side plates of the screen box crack.
Vibrating screen troubleshooting: Adopt the riveting method to connect side plates, reinforcing plates, and wing plates.
③ The included angle of the eccentric blocks is not consistent, and the specifications, model, material, and quality of the weight blocks are different.
The inconsistent angle of the eccentric blocks will cause the direction of the exciting force to be inconsistent, causing abnormal vibration of the vibrating sieve, and leading to the cracking of the side plate.
Usually, weight blocks are added to change the vibrator’s mass and amplitude according to the demand. If the weight blocks are not added properly, it will also cause vibration abnormity.
Vibrating screen troubleshooting: When disassembling, repairing, and assembling the exciter, it is necessary to ensure that the specification, model, material, and quality of the eccentric blocks are the same. During installation, the included angle of the eccentric blocks must be the same. Counterweights of the same specification, model, material, and quality shall be symmetrically installed on both sides of the screen.
Heating Problems in Bearing
Under normal circumstances, the vibrating screen bearing temperature shall be at 35 ~ 6O ℃ after the vibrating sieve has a 4-hour test without load. If the bearing temperature is too high, it may be caused by the following reasons.
① Wrong vibrating screen bearing mode
The bearing at the vibration exciter part is overheated, and there is no improvement after adding lubricating oil, so the bearing model is likely unreasonable. If the radial clearance of the bearing is too small, it will cause overheating and wear.
Vibrating screen troubleshooting: It is recommended to use bearings with large radial clearance. If it is a bearing with ordinary clearance, the outer ring of the bearing can be ground to extend the clearance.
② Too little or too much lubricating oil or the quality of lubricating oil that does not meet the requirements will also cause overheated bearing.
If the bearing is lubricated improperly, dry friction will occur. The heat generated by dry friction in a short period is enough to melt the metal, causing damage to the bearing or even seizure.
Vibrating screen troubleshooting: Regularly open the bearing end cover for inspection; timely fill in the lubricating oil that meets the requirements; Don’t fill up too much when refueling.
③ The gland is firmly against the outer ring of the bearing.
There should be a gap between the gland and the outer ring of the bearing to ensure heat dissipation and axial movement.
Vibrating screen troubleshooting: Adjust the gasket between the end cover and the bearing seat to adjust the gap.
④ Slime entering the bearing end cover can also cause the bearing to heat up.
Vibrating screen troubleshooting: Clean dirty bearings; Replace the sealing ring and check the sealing condition frequently to ensure a good sealing condition.
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