Increasing the Reliability of Over-Hung Fan Bearings

One of the most common issues fan operators face is bearing failure due to excessive vibration and temperature.

For an overhung fan, the typical arrangement is two independent pillow block ball bearings (see picture below). While this arrangement has shown to be satisfactory in some cases, history has proven it to be overly sensitive to movement, misalignment, and contamination. Over time, unexpected shutdowns and recurring maintenance have resulted in loss of time and production.

So what can be done to modify these fans for improved reliability?

The answer is housing the two independent bearings in a single mono-block housing with robust sealing to prevent contaminant ingress. Robinson Fans BLO bearing is one way to accomplish this.

The Robinson BLO mono-block housing has the bearing bores lined-drilled and finished providing a tightly-tolerance machine alignment that is not possible to sustain over time with field aligned independent bearings.

The bearings are oil lubricated by means of a flinger ring which is immersed in oil sump. The seals on the unit are of a labyrinth design and the seal rings which are located on the shaft have machined V-grooves to prevent oil leakage. Ingress of contamination can be further avoided by regularly lubricatable grease chamber located in covers.

It is not uncommon for the mean-time between failure (MTBF) of bearings to increase by multiple times when fan bearings are upgraded to the Robinson BLO system. Additional details about the system are below:

• Two-bearing unit ensures precision alignment of bearing inserts
• Includes two single-row, deep groove ball bearings (Alternate bearing combinations available upon request)
• Higher speed capabilities than separate pillow block housings
• Ideal for fans and other overhung rotating equipment
• Heavy cast iron construction
• Oil lubrication
• Shaft size ranges from 65 mm to 100 mm
• Complete BLO line acquired from Dodge/Baldor/ABB

If you're looking to improve your fan's reliability, reach out to us - we're here to help!