Sealless gear pumps reborn: AxFlow managing director Tony Peters looks at a new design of sealless pump

摘要

In June 1990 a USA consultancy firm predicted that sealless gear pumps would take an increased percentage of the market - "probably 25% by 1995 and 50% by 2000". That didn't happen. The technology at that time was not reliable enough, with too many instances of failures that were brought about by excessive bearing loads and design deficiencies that led to breakdown and leakage issues. These failures created a stigma that many manufacturers of sealless pumps are still trying to overcome today. Adopting a fresh, clean-sheet approach to confronting the conundrums inherent in traditional sealless pump design has led to the creation of a new line of sealless gear pumps. In short, the new Envirogear pump increases reliability while eliminating the unacceptably high ownership, maintenance and environmental costs that have dogged previous sealless gear pump designs. With its simple design comprising seven primary parts, the Envirogear pump is designed to eliminate all the operational concerns found in old-style sealless gear pumps. The leading causes of high maintenance in conventionally sealed pumps include those associated with mechanical seal replacement and the premature wear of the bushings and close-fitting metal parts due to insufficient support of the rotating pumping elements. There are also the environmental costs of leakage include cleanup, possible forced shutdown and environment hazard fines and penalties, plus the resulting bad press and community mistrust if a leak or accident occurs.