Centrifugal fan is a kind of mechanical energy that converts the mechanical energy of the original motive into the transport gas and gives the gas energy machinery. It is an indispensable mechanical equipment in the cement plant. It mainly includes the centrifugal fan, the centrifugal fan, the centrifugal fan, the sealed centrifugal fan and the centrifugal fan, etc., in the actual operation of the centrifugal fan, especially the centrifugal fan. The operation conditions are bad, the failure rate is high, and the cause of the failure of the centrifugal fan is quickly judged, and the effective measures to solve the fault are the guarantee of the continuous safe operation of the factory. The fault types of centrifugal blower are various and the reasons are very complicated, but it is found that the fault of centrifugal fan in actual operation is mostly caused by the vibration of the bearing, the high temperature of the bearing, the astringent of the movable leaf and the misoperation of the protective device.
One, the bearing vibration exceeding standard of centrifugal fan
The vibration of centrifugal fan bearing is a common fault in operation. The vibration of centrifugal fan will cause damage of bearing and blade, loosening of bolt, damage of casing and air duct and so on, which seriously endangers the safe operation of centrifugal fan.
There are many reasons why the vibration of the centrifugal fan exceeds the standard. If we can take appropriate measures for different reasons, we can get twice the result with half the effort.
1. Deal with the non working area of blades and reduce the vibration of centrifugal fans.
This kind of defect is common in the centrifugal fan of the mill. The phenomenon is mainly due to the sudden rise in the vibration of the centrifugal fan. This is when the gas enters the impeller, and there is a certain angle with the working face of the rotating blade. The principle of fluid mechanics, the non working surface of the gas blade must have whirlpool, and the action of the gray particle swirl in the gas will slowly deposit on the non working surface. The wing blade is easy to accumulate ash, and when the ash reaches a certain weight, the impeller rotates centrifugal force to throw a large mass of ash out of the impeller. The dust accumulation on the blade can not be completely uniform, and the time of gathering or removing ash blocks is not always synchronized. The result of uneven ash accumulation results in uneven distribution of the mass distribution of the impeller and increases the vibration of the centrifugal fan.
In this case, the ash is usually removed and the impeller will be re balanced so as to reduce the vibration of the centrifugal fan. In actual work, the usual way of handling is to open the centrifugal fan shell and manhole door after temporary shutdown, and the maintenance personnel enter the casing to clear ash on the impeller. In such a bad environment, unsafe factors cause unplanned outage, long maintenance time and strong labor intensity.
2. Vibration of air duct system leads to vibration of centrifugal fan
The vibration of the smoke and air duct usually causes the forced vibration of the centrifugal fan. The inlet and outlet of the centrifugal fan will increase with the increase of the load, and the vibration will also change. Conversely, the inlet area of the centrifugal fan inlet is not uniform. If the baffle is closed, it will cause vibration of the impeller.
3, the dynamic and static part of the collision caused the vibration of the centrifugal fan
The main reasons for the collision between moving parts and static parts in production practice are:
(1) impeller and inlet (collector) are not on the same axis.
(2) the running time is long and the back inlet is damaged and deformed.
(3) the loosening of the impeller makes the sloshing of the impeller large.
(4) bearing damage
(5) the bending of the spindle
Different treatments are taken in different situations. There are many reasons for the vibration of the centrifugal fan, such as the large deviation of the center of the shaft, the lack of rigidity of the base or the frame, the vibration of the original motive, and so on. It is the result of many reasons. In actual work, we should carefully sum up experience, accumulate more data, master the state of equipment, and find out the law of equipment deterioration, and we should take the corresponding measures to solve the problem.
二、軸承溫度高Two. High temperature of bearing
There are three reasons for abnormal temperature rise of centrifugal fan bearing: poor lubrication, insufficient cooling and abnormal bearing. The centrifugal fan bearing is placed outside the centrifugal fan. If the bearing fatigue wear is peeled, flax pit, and gap increases the temperature increases, it can usually be judged by the methods of bearing sound and measuring vibration, such as bad lubrication and insufficient cooling, it is easier to judge. The axial flow centrifugal fan bearing is concentrated in the bearing box and placed under the intake chamber. When the bearing temperature is high, the centrifugal fan is running. It is difficult to judge the problem of lubrication and cooling of the bearing. In actual work, we should first solve the problem from the following aspects.
1, whether the refueling is appropriate. Regular work should be required to refuel the bearing box. Bearing oil will also appear after the temperature is high, the main refueling too much. At this point, the temperature continues to rise, after reaching a point (generally 10 to 15 degrees centigrade above normal operating temperature) will remain unchanged, and then gradually decrease.
2. The cooling centrifugal fan is small, and the cooling air volume is insufficient. There is no effective cooling of the bearing box, the bearing temperature will increase, and the solution is simple at the same time, and the solution method is to set the compressed air cooling for the hub side bearing. When the temperature is low, the compressed air can not be opened, and the compressed air is cooled when the temperature is high.
3, confirm that there is no such problem before checking common centrifugal fan bearing box.