RELIABILITY IMPROVEMENTS TO A HIGH SPEED/HIGH ENERGY PUMP

摘要

The paper describes the problems encountered and solutions that were implemented to improve the reliability of a high speed/high energy centrifugal pump. Two of these pumps were originally installed in 1984, with a third installed in 1989 because of a unit expansion. The reliability of the pumps was improved in 1995 when the original stainless steel impeller and inducer were replaced with titanium, to raise the output shaft critical speed above the pump operating speed. However, the reliability of the pumps continued to be an issue with as many as seven failures in 2001. A plan was put together to address the reliability problems by modifying the gearbox seal, the secondary sealing system, and the tilting pad bearing design on the output shaft. These improvements have lowered the shaft vibration and greatly improved the reliability of the pump and gearbox. A discussion of the rotordynamic analysis used to change the bearing design is included, along with the effects of the impeller/inducer material change. Likewise, how the improved secondary sealing system improved the synchronous vibration is also discussed.