1. Normal shutdown
The normal shutdown of the centrifugal fan unit is operated according to the following procedures.
a. Gradually open the vent valve (or outlet bypass valve) and gradually close the exhaust valve.
b. Gradually close the intake throttle of the centrifugal fan to 20-25°.
c. Press the stop button and pay attention to whether the fan is abnormal during the shutdown process.
d. The oil supply can be stopped after the unit is stopped for 5-10 minutes, or the bearing temperature drops below 45℃. For units with floating ring seals, the sealed oil pump must continue to supply oil until the body temperature is lower than 80°C.
After the centrifugal fan unit is stopped, the rotor should be regularly rotated by 180° within 2 to 4 hours.
2. Emergency shutdown
During the trial operation of the unit, if one of the following situations occurs, an emergency shutdown should be made immediately.
The operation of emergency shutdown is to press the main motor stop button, and then perform the aftermath of the shutdown.
1. The centrifugal fan body vibrates violently and has exceeded the trip value.
2. There is a scratching or abnormal rubbing sound inside the body.
3. The fan seal or bearing smokes, or the temperature of a certain bearing rises sharply to the alarm value (normally, the temperature rise of the fan bearing does not exceed 40℃, and the operation in this range is a safe value).
4. The oil tank of the centrifugal fan is insufficiently liquid, and there is a phenomenon of suction. When the oil pressure is lower than the alarm value and cannot be restored to the normal value.