Gate valve having fluid pressure seal and limit stop means

Claim 1

A HIGH VACUUM GATE VALVE FOR USE IN A PARTICLE ACCELERATOR VACUUM SYSTEM COMPRISING IN COMBINATION A METAL HOUSING HAVING TWO APERTURED WALLS, A METAL GATE, MEANS FOR ADVANCING SAID GATE INTO AND OUT OF A POSITION INTERVENING BETWEEN THE APERTURES IN SAID WALLS, GATE-STOP MEANS SUPPORTED SO AS TO ABUT THE ADVANCE EDGE OF SADI GATE AT THREE PLACES WHEN SAID GATE IS IN SAID INTERVENING POSITION AND THEREBY PREVENT FURTHER ADVANCE MOVEMENT OF SAID GATE, TWO OF SAID PLACES OF ABUTMENT ON SAID ADVANCE EDGE COMPRISING TWO LATERAL SURFACES SO DISPOSED AS TO PREVENT LATERAL MOVEMENT OF SAID GATE, SAID THIRD PLACE OF ABUTMENT BEING SO DISPOSED AS TO PREVENT DOWNWARD MOVEMENT ONLY OF SAID GATE, A KNIFE-EDGE MOUNTED ON ONE OF SAID WALLS ABOUT THE APERTURE THEREIN, A METAL CHAMBER HAVING FLEXIBLE BOUNDARIES MOUNTED ON THE INTERIOR OF THE OTHER WALL SO THAT SAID CHAMBER LIES ABOUT THE APERTURE THEREIN, AND MEANS FOR INTRODUCING A FLUID UNDER PRESSURE INTO SAID CHAMBER TO EFFECT EXPANSION THEREOF AND CAUSE SAID GATE TO BE PRESSED AGAINST SAID KNIFEEDGE.