Overflow type ball mill, also called overflow ball mill, is a kind of wet grinding ball mill, commonly used in the dressing plant, cement plant, power plant, and other enterprises. During the operation, some common faults will affect the performance and production efficiency of overflow ball mills. What are the common faults? How to avoid them? These two issues are the biggest concerns of manufacturers. Next, we will do some analysis, find the causes, and put forward reasonable solutions.
Common Faults & Causes Of Overflow Type Ball Mill
Fault 1:the temperature of the main bearing is too high.
Causes
The installation position of the main bearing does not meet the requirements, resulting in excessive temperature.
Material slurry or impurities such as mud and sand enters the friction surface between journal and bearing bush, resulting in intensified friction and heating.
Except that a small part of the heat generated by the main bearing is conducted out by gold chips, a large amount is taken away by lubricating oil. Whether the lubricating oil is too thick or too thin will lead to direct metal friction and increased heating.
Fault 2:the gear transmission has a collision sound or strong vibration.
Causes
Pinion fracture;
Excessive radial run-out of big gear ring;
The screws on the bearing end cap are loose;
The bearing on the gearing shaft is excessively worn;
The connecting bolt or screw of the big gear ring is loose;
The gear machining accuracy does not meet the requirements;
Incorrect meshing or over-wearing of big gear ring and pinions;
Fault 3:there is water mixed in the lubricating oil.
Causes
A broken pipe in the oil cooler leads water to enter the oil return system, hindering the formation of the oil film.
Fault 4:the pressure of lubricating oil is too high or too low.
Causes
The viscosity of lubricating oil is not up to standard.
The poor quality of the lubricating oil causes the filter to be blocked.
The oil pipe in the lubrication system is blocked so the lubricating oil is not enough.
Fault 5:the quality of the lubricating oil deteriorates.
Causes
When the sealing device is not tightly sealed, the material slurry or particles fall into the main bearing and journal, which worsens the lubricating oil quality and greatly reduces its service life.
Fault 6:the cylinder lining plate is seriously worn.
Causes
When the height difference between the crest and trough of the cylinder lining plate reaches about 60% of the grinding ball diameter, the grinding ball motion intensity is moderate. However, some improper operations in work will lead to deviation, resulting in serious wear of lining plate.
Fault 7: the big gear ring is cracked.
Causes
The crack is caused by long-time heavy load operation. It belongs to fatigue crack.
Overflow Type Ball Mill Onsite
Reasonable Solutions For Common Faults
Regularly check the wear of cylinder lining plate and timely adjust the proportion of steel balls.
Regularly check the installation position of the main bearing to ensure that it meets the specified requirements.
Regularly check the contact between the hollow shaft journal and the bearing bush to ensure that it meets the specified requirements.
If there is water mixed in the lubricating oil, we should find out the cause and resolve it. In serious cases, the oil tank should be cleaned and replaced with new oil.
Regularly check the lubrication of the hollow shaft journal. If the hollow shaft journal and the main bearing are short of lubricating oil, we should replenish the oil in time.
Regularly check the operation of oil pumps, filters, valves, and pipelines in the lubrication station, as well as the pressure and temperature of lubricating oil. In case of oil pump failure, it shall be repaired or replaced in time.
During operation, pay attention to check whether the ball mill cylinder leaks slurry, and carefully observe whether the current, voltage, feeding, and water supply are normal. The main shaft temperature shall not be greater than 60 ℃.
Regularly check whether there is oil leakage in the oil pump pipeline and each lubricating point and whether it is unobstructed. Pay special attention to the temperature rise of motor bearing, reducer, and transmission bearing (no more than 60 ℃).
Regularly check the meshing clearance between the big gear ring and pinion to ensure that the clearance is within the specified range. The backlash between the gear pair is 1.60-1.90mm, which can be increased by 0-0.5mm according to the actual operation. If the pinion is excessively worn, it shall be replaced in time.
Regularly check the quality of lubricating oil. If a large amount of dust enters the lubricating oil, we should stop the ball mill immediately for inspection, find out the cause of leakage, clean the oil tank, and replace it with new oil. If material slurry or particles fall into the main bearing and hollow shaft journal, we need to clean the bearing and journal and replace them with new oil.
The above are some common faults of overflow ball mills during operation. We analyzed the causes one by one and presented solutions. I hope it helps.
