Basic operation of normal shutdown of centrifugal fan

- Apr 15, 2019-

When assembling the centrifugal fan casing, the position of the casing should be corrected based on the rotor shaft line and the axial and radial clearance between the impeller inlet and the casing inlet should be high-speed within the range specified in the equipment technical documents. Also check that the anchor bolts are tight.

 If the gap value is not specified in the technical documentation of the equipment, the general axial clearance should be 1/100 of the outer diameter of the impeller, and the radial clearance should be evenly distributed. The value should be 1.5/1000~3/1000 of the outer diameter of the impeller. Smaller diameters take large values). When adjusting, try to make the gap value smaller to improve the fan efficiency. Normal shutdown is performed as follows.

1. Gradually open the vent valve (or outlet bypass valve) and gradually close the vent valve.

2. Gradually close the small intake throttle to 20 to 25°.

3. Press the stop button and pay attention to whether there is any abnormality during the shutdown process.

4. After the centrifugal fan stops for 5 to 10 minutes, or when the bearing temperature drops below 45 °C, the oil supply can be stopped. For units with a floating ring seal, the sealed oil pump must continue to supply oil until the body temperature is below 80 °C. After the unit is stopped, the rotor should be rotated 180° periodically within 2 to 4 hours.