Brimhall Industrial - Solutions for Industry

United Centrifugal High Pressure Drain Pump

The Issue

United Centrifugal High Pressure Heater Drain Pumps require high temperatures and pressures, which can take a toll on packings and other components inside the pumps. In this particular case, the packings were only lasting weeks in our client's pumps. This was costing our client heavily in unplanned maintenance and downtime. Some of the issues affecting the pumps included:

Constant bearing failure due to spraying water entering bearings
Bearing failure leading to thrusting and damage to impellers, case rings and volute.
Constant replacement of case rings and spacers
Scored and worn packing sleeves due to heat and constant tightening of the gland followers

The Solution

We first machined a new element with a 416 stainless shaft, 400 series hardened stainless case rings, a center stage ring, spacers and wear rings. The individual impellers were then dynamically balanced. We then balanced the stacked element to ensure vibration-free running. The runout of the stacked element was then checked for quality.

Close tolerance throat bushings were then installed to provide a friendly seal environment. We then installed Chesterton 180PR pump ring mechanical seals. The final process was to install ITT tube and shell heat exchangers (API Flush Plan 23).

The Result

After precision remanufacturing these pumps with this configuration, while the process fluid is 285 F and above, the stuffing box temperatures are below 180 F. The mechanical seal body is approximately 160 F.

The pumps run smooth and vibration-free with no leaks. The client is extremely happy with their increased service life and reduced maintenance costs and has decided to convert all of their pumps to this configuration.