Abstract: A tip seal for use in a scroll-type vacuum pump includes a seal element and an energizer element affixed to the seal element. The scroll-type vacuum pump includes first and second scroll blades that are nested together to define one or more interblade pockets, and an eccentric drive that produces orbiting movement of the first scroll blade relative to the second scroll blade. At least one of the first and second scroll blades has a seal groove along an edge thereof. The tip seal is positioned in the seal groove between the first and second scroll blades. The energizer element is formed of a resilient material having multiple compressible voids, so that the energizer element having compressible voids is more compressible than the resilient material alone, when confined by the seal groove. In one embodiment, the energizer element is a foam such as a low porosity urethane foam. In another embodiment, the energizer element is an elastomer material having a predetermined pattern of voids.

Abstract: A self-cleaning pressure relief valve has a spring-biased valve closure with an annular contact edge which makes contact with an o-ring to seal the valve. The annular contact edge is slightly larger in radius than the central radius of the o-ring so that changing pressure on the closure causes the contact edge to slide along the surface of the o-ring.

Abstract: In accordance with the invention, a hermetic refrigerant compressor pump which is used to compress helium is cooled by fins which are press fitted to the compressor's housing. The compressor is further cooled by a heat exchanger which cools oil in an oil sump located within the compressor housing. Preferably, a fan is located between the fins and the heat exchanger to help cool the pump.