Rotary valve

A rotary valve, comprising:

• a casing having a wall defining a cylindrical bore having a cylindrical edge surface, a plurality of grooves extending substantially axially in said cylindrical edge surface, and said casing having a first opening for taking in a first gas, a second opening for discharging a second gas and a third opening communicating with a chamber, the chamber taking in the first gas and discharging the second gas;
• a rotor including a cylindrical portion mounted within said bore with a predetermined clearance defined between a cylindrical surface of the cylindrical portion of said rotor and the cylindrical edge surface of said bore, said rotor including means for selectively fluidly connecting the first and second openings to the third opening;
• first sealing means for sealing possible leaks in the first and second gases from the selectively fluidly connecting means in the axial direction of said rotor;
• and
• second sealing means for sealing possible leaks in the first and second gases from the selectively fluidly connecting means in the radial direction of said rotor;
• said second sealing means comprising a plurality of radial seals mounted in said grooves of said casing and extending substantially axially of said rotor, each of said radial seals having an arcuate surface directed toward said rotor, and spring means for biasing each of said arcuate surfaces of said radial seals into substantially tangential contact with the cylindrical surface of said rotor, whereby frictional contact is minimized between said rotor and said radial seals.