This article will illustrates how to replace drive shaft and bearings on centrifugal fans.
Open the upper part of the water-cooled bearing box of the centrifugal fan, and we can see the drive shaft and bearings inside. Next, we will continue to explain the replacement steps:
Remove the taper pin and rubber spring pad connecting the two couplings, remove the bearing box from the steel frame, and be careful to save the iron pads under the four foundation seats.
Open the upper part of the bearing box, and you can see the installation method and installation position of the bearing, oil seal, lock, and cap. The new transmission shaft is installed according to the old transmission installation method.
First install the bearing. The bearing needs to be heated with boiling oil for 15-20 minutes, and then installed on the impeller of the transmission shaft while it is hot. Then install the locking plate, back cap, and oil seal in sequence.
Put the installed drive shaft into the bearing box. Note: There are holes in both sections of the drive shaft. One end of the wire is the impeller part. After applying engine silicone sealant to th
e joint part of the upper and lower covers of the bearing box, remove the bearing. Cover the upper part of the box, first insert the positioning pin into the positioning hole, then put the rubber ring into the large end cover, tighten it with bolts, and then install the coupling into the drive shaft.
After tightening the bearing box bolts, install it on the steel frame at the original disassembly position. At this time, the concentricity of the transmission shaft and the motor shaft and the gap between the coupling shaft should be rechecked or adjusted. The gap between the two couplings is 2-3 mm, and the gap between the couplings keeps the drive shaft and the motor at the same center. At the same time, the two end faces of the two couplings should be parallel to the same radial plane, that is, the gaps between the dif
ferent positions of the two couplings should be equal. This process is very critical. Improperly adjusted high-pressure centrifugal fans can vibrate.
After adjusting the concentricity of the drive shaft and the coupling clearance, tighten the four anchor bolts of the bearing box.
Install the impeller. Polish and wipe the impeller shaft hole and transmission shaft head clean, apply butter or other grease, and heat the shaft hole evenly with a low-temperature (orange) flame of acetylene gas. Be careful not to let the flame stay in the shaft hole to avoid high temperature damage to the shaft disk. After heating for about 15 minutes, install it on the drive shaft. You can place a thin plate at the shaft hole and hit it with a sledgehammer or round steel. After installation, use bolts to fix the gland on the shaft hole.
Refill one-half of the oil window in the bearing box. Manually rotate the coupling. There will be no abnormal noise from the impeller, casing, bearing box and other parts. The coupling taper pin and protective cover can be installed, and the power supply of the high-temperature centrifugal fan can be connected. Trial run.
