HYBRID SPOOL VALVE FOR MULTI-PORT PULSE TUBE
The problems of reducing the torque required to turn the valve, eliminating wear dust, and extending the life of the valves in Gifford McMahon (G-M) type multi-port pulse tube refrigerators are solved by using a rotary spool valve having radial clearance to control flow to and from the regenerator, and using face seal ports on the end of the spool to control flow to and from the pulse tubes.