Abstract: In the embodiment of the invention as depicted, the same comprising a rotary compressor, a channel or passageway is provided in the machine to communicate two variable volume chambers which are formed by rotary pistons and walls of the compressor housing, to equalize pressure in the two chambers. The purpose here is to prevent one chamber from pre-compressing before the other, so that a small pocket formed between the rotors by the inter-engaging teeth will not come up to pressure, and be expanded back into the inlet, to avoid a clearance loss and a waste of horsepower.

Abstract: The novel seal comprises a non-contacting, floating ring seal formed, by injection molding, of carbon fiber-reinforced polyphenylene sulfide, for use in fluid-sealing a rotary steel shaft. The reinforced polyphenylene sulfide exhibits thermal expansion which is substantially equal to that of steel; thus a predetermined radial clearance is maintained, between the seal and the shaft without the need for a circumferential steel band, or the like, shrunk onto the seal.