greaseless vacuum-tight valve

Claim 1

A VALUE COMPRISING IN COMBINATION A UNITARY VALVE BODY HAVING THEREIN A BORE WITH A RIGHT CIRCULAR CYLINDRICAL BORE WALL AND AT LEAST TWO TRANSVERSE FLUID PASSAGES THAT OPEN INTO THE BORE THROUGH MOUTHS THAT ARE MUTUALLY SPACED IN SAID WALL; AND A VALVE MEMBER THAT INCLUDES A RIGHT CIRCULAR CYLINDRICAL STEM COAXIALLY RECEIVED IN THE BORE AND MOVABLE THEREIN BETWEEN A CLOSED POSITION IN WHICH ITS CYLINCRICAL SURFACE COVOERS AT LEAST ONE OF THE PASSAGE MOUTHS IN FLUID SEALING RELATION AND AN OPEN POSITION EXPOSING BOTH THE PASSAGE MOUTHS TO PERMIT FLUID FLOW THEREBETWEEN, THE OPPOSING CYLINDRICAL FACES OF THE STEM AND BORE BEING FREE OF LUBRICANT; THE VALVE BODY AND THE STEM OF THE VALVE MEMBER BEING FORMED BOTH OF THE SAME SOLID POLYETHYLENE MATERIAL SELECTED FROM THE GROUP CONSISTING OF POLYMERIZED TETRAFLUOROETHYLENE AND POLYMERIZED TRIFLUOROMONOCHLOROETHYLENE; THE DIAMETER OF STEM BEING LARGER THAN THE DIAMETER OF THE BORE BY AN AMOUNT SUBSTANTIALLY WITHIN THE RANGE FROM 0.0002 TO 0.0006 INCLUSIVE, THE STEM OF THE VALVE MEMBER BEING INSERTABLE IN THE BORE AND MANUALLY MOVABLE THEREIN IN COMPLETE ABSENCE OF LUBRICANT, AND THE OPPOSING CYLINDRICAL FACES OF THE STEM AND THE BORE FORMING A FLUID SEAL IN COMPLETE ABSENCE OF LUBRICANT.