Upon inspection, the shaft had a sleeve installed over the original shaft and a modern Spherical Roller bearing was installed over that. The sleeve was installed at one time in attempt to save the fan shaft. The bearing journal under the sleeve had worn. The original fan shaft is almost 100 years old. In the 20’s and 30’s oil film babbit bearings were used. The shaft was the friction surface. At some time, that bearing surface reached its service life. The repair sleeve had come loose from the shaft.
The arrow depicts the worn gap. The sleeve was held to the shaft using eight pinch bolts, four you see and four behind the bearing.
There was little choice other than to replace the shaft or repair in place. A solution, a combination of both was employed. The fan shaft was suspended and jacked, held in its original position. We cut damaged end of the shaft off completely.
Fitted was a custom made a new shaft end, interference fitted over the large 5” center section of the shaft. The original bearing was cleaned, inspected and reused. Proper clearance reduction during mounting was performed.
The Final Result
The final result is a correctly fitted and installed rolling element bearing on a new shaft surface. The procedure saved thousands in complete shaft replacement. Access was difficult. The only door is a 2 x 4 foot opening obscured with hot steam pipes. No overhead beams were available for lifting. This made the method of repair even more desirable.
The fan wheel is 90 plus years old. Getting the fan off the shaft would be very difficult and may cause damage to the fan wheel.
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