new industrial ventilation fan

The centrifugal fan is based on the principle of converting kinetic energy into potential energy, using a high-speed rotating impeller to accelerate the gas, then decelerate, change the flow direction, and convert kinetic energy into potential energy (pressure). In a single-stage centrifugal fan, the gas enters the impeller from the axial direction, changes to the radial direction when the gas flows through the impeller, and then enters the diffuser. In the diffuser, the gas changes the direction of flow and the cross-sectional area of the pipe increases to decelerate the flow. This deceleration converts kinetic energy into pressure energy. The increase in pressure mainly occurs in the impeller, followed by the expansion process. In a multi-stage centrifugal fan, a refluxer is used to make the air flow into the next impeller, generating higher pressure.
Shutdown procedure:
1. 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 suddenly vibrates strongly and has exceeded the trip value.
2. There is a scratching or abnormal rubbing sound inside the body.
3. There is smoke from any bearing or seal, or the temperature of a certain bearing rises sharply to the alarm value.
4. When the oil pressure is lower than the alarm value and cannot return to normal.
5. The liquid level of the fuel tank is low and there has been a phenomenon of emptying.
6. When the axis displacement value has obvious and continuous increase and reaches the alarm value.
Normal shutdown: The normal shutdown of the unit is performed according to the following procedures.
1. Gradually open the vent valve (or outlet bypass valve) and gradually close the exhaust valve.
2. Gradually close the air intake throttle to 20～25°.
3. Press the stop button and pay attention to whether there is any abnormality during the shutdown process.
4. 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 unit is stopped, the rotor should be regularly rotated 180° within 2 to 4 hours.