Bakeable, leakproof, straight-through ultra-high vacuum valve

Claim 1

A STRAIGHT-THROUGH, LEAKPROOF VALVE COMPRISING A VALVE BODY HAVING A BORE THERETHROUGH; AND A COUNTERBORE ON ONE FACE OF SAID BODY ENCOMPASSING SAID BORE; A GATE, GENERALLY IN THE FORM OF A DISC, LOCATED IN SAID COUNTERBORE AND LOOSELY FITTING THEREIN, LARGE ENOUGH TO SPAN SAID BORE WHEN IN CLOSED POSITION TO CLOSE SAID BORE BY SEALING AGAINST THE BASE OF SAID COUNTERBORE AROUND SAID BORE, AND WHEN FREE OF EXTERNAL AXIAL PRESSURE, FREELY MOVABLE WITHIN SAID COUNTERBORE BETWEEN CLOSED POSITION AND OPEN POSITION, IN WHICH LATTER POSITION IT LEAVES COMPLETELY UNOBSTRUCTED PASSAGE THROUGH SAID VALVE STRAIGHT THROUGH SAID BORE; A DIAGRAGM MEMBER FIXED IN FLUID-TIGHT SEALING RELATION TO SAID FACE OF SAID VALVE BODY TO FORM A LEAKAGE CHAMBER INCLUDING SAID COUNTERBORE; SAID DIAPHRAGM MEMBER INCLUDING A DIAPHRAGM, A HUB CARRIED BY SAID DIAPHRAGM AND MOUNTED FOR TO AND FROM MOTION GENERALLY AXIALLY OF SAID BORE BOTH TO BEAR SEALINGLY AGAINST SAID GATE TO EXERT PRESSURE THEREON TO SEAL SAID GATE AGAINST THE BASE OF SAID COUNTERBORE OVER SAID BORE TO CLOSE SAID VALVE AND ALSO TO RELEASE PRESSURE FROM SAID GATE, SAID HUB DEFINING A FLOW PASSAGE THROUGH SAID DIAPHRAGM MEMBER COMMUNICATING WITH SAID BORE WHEN SAID GATE IS IN THE VALVE OPEN POSITION, AND MEANS FOR APPLYING PRESSURE TO SAID GATE WHEN SAID GATE IS IN OPEN POSITION TO FORCE SAID GATE AGAINST SAID VALVE BODY TO RETAIN SAID GATE IN OPEN POSITION; MEANS FOR APPLYING FORCE TO SAID HUB TO URGE IT AXIALLY OF SAID BORE; MEANS FOR EVACUATING SAID BORE; AND MEANS FOR EVACUATING SAID LEAKAGE CHAMBER.