Case Studies

A power plant had problems with IR 16VEM boiler circulating pumps and with IR 3VEM injection water pumps. Premature bearing failure after a few months running time.

We found that the shaft and shaft sleeves where made of wrong material. We worked with MRC/SKF Bearing Manufacturing engineering team to come with the correct clearance on all bearings.

Bearing housings where line bored and machined to the correct sizes. New shafts and shaft sleeve where made with the correct bearing fits and running clearance.

New labyrinth sleeves with smaller running clearances where made. This reduced the pressure the mechanical seal have to operate in.

Lower carbon bearing was replaced with a metalized carbon bearing to give it a longer run time.

New mechanical seal housings where made with larger inside cooling water spaces thereby reducing the temperature of the mechanical seal.

Pumps where assembled with correct amount of upward trust.

The pumps (6) have been running for over 3 years and are still in service.

The customer has seen a large reduction in maintenance cost for these very important pumps. End suction pumps used for pumping diesel oil had a bad failure rate. 1 pump failed after a few weeks running time. Several thousand barrel of oil leaked in the water and ground. We were called in as a 3rd party to dismantle the pump and find the root cause of the failure. The bearings had spun loose in the bearing housing due to vey loose fit, impeller and casing wear rings badly worn. Mechanical seal ceramic seat was broken into several pieces.

The pump was rebuilt by NEPV, Inc. The bearing housing was line bored and re-sleeved, all wear rings replaced. Rotating element dynamically balanced. A cartridge type mechanical seal was installed with the correct O-rings and with tungsten carbide to reinforced carbon seats. Pump was installed and laser aligned and has run for 3 ½ years with no problem.

We have since then rebuilt over 20 pumps for the same tank farm.