Dry air rotary pump or compressor

A dry air rotary pump or compressor comprising:

• a stator housing having a cylindrical inner wall;
• a pair of end heads mounted on the opposite ends of said stator housing to form a cylindrical pump cavity;
• a drive shaft eccentrically journalled on one of said end heads, and extending in the interior of the pump cavity;
• a rotor mounted on said drive shaft within said pump cavity and co-operating with the cylindrical inner wall of said stator housing and with the inner end walls of said end heads to form suction and compression or delivery chambers;
• a pair of flexible diaphragm type sealing plates clamped on the opposite ends of said stator housing by said end heads to be pressedly contacted with the opposite end faces of said rotor, each of said sealing plates being made of a composite consisting essentially, by weight, of 10.0 - 75.0% carbon and/or graphite, 0.1 - 60.0% molybdenum disulfide, 1.0 - 20.0% fluorine resin, and the remainder, which is greater than 25.0% of the total composition by weight, being heat resistant synthetic resin without fluorine resin to have a coefficient of elasticity greater than 200 Kg/cm.sup.2 ;
• and
• a pair of recesses provided on the inner end walls of said end heads to form a pair of pressure chambers behind each of said sealing plates.