Gate valve

Claim 1

IN A GATE VALVE HAVING A BODY WITH A FLUID PASSAGE EXTENDING THERETHROUGH, SAID BODY HAVING A GATE CHAMBER TERMINATING IN A GENERALLY CIRCULAR HEAD HAVING A PLURALITY OF SPACED OPENINGS ARRANGED IN A CIRCLE, A GATE MOVABLE BACK AND FORTH IN THE GATE CHAMBER TO CLOSE AND OPEN SAID PASSAGE, AND A PISTON OPERATOR MOUNTED ON SAID HEAD AND OPERATIVELY CONNECTED TO THE GATE FOR MOVING THE GATE BACK AND FORTH, SAID PISTON OPERATOR INCLUDING A CYLINDER HAVING AN OUTWARDLY EXTENDING FLANGE ON ONE END THEREOF FORMING A RIM WITH AN OUTER DIAMETER SUBSTANTIALLY GREATER THAN THE DIAMETER OF SAID HEAD, THE IMPROVEMENT COMPRISING: AN ADAPTER PLATE MOUNTED ON SAID HEAD BETWEEN THE HEAD AND SAID CYLINDER AND FORMING AN END FOR THE CYLINDER, SAID ADAPTER PLATE BEING GENERALLY DISCLIKE IN SHAPE WITH A DIAMETER SUBSTANTIALLY EQUAL TO THE OUTSIDE DIAMETER OF SAID RIM AND HAVING A PLURALITY OF SPACED OPENINGS EXTENDING COMPLETELY THROUGH SAID PLATE AND ARRANGED IN A CIRCLE IN AXIAL ALIGNMENT WITH THE SPACED OPENINGS ON SAID HEAD, SAID ALIGNED SPACED OPENINGS HAVING AT LEAST A PORTION THEREOF WITHIN AN AREA DEFINED BY AN AXIAL EXTENSION OF THE INNER PERIPHERY OF THE CYLINDER, A CIRCUMFERENTIAL RAISED PORTION ON ONE FACE OF THE ADAPTER PLATE FITTING WITHIN THE CYLINDER TO POSITION THE CYLINDER RELATIVE TO THE ADAPTED PLATE, AND THE OPPOSITE FACE OF SAID ADAPTER PLATE HAVING A CIRCUMFERENTIAL GROOVE RECEIVING SAID HEAD IN INTERFITTING RELATION WHEREBY SAID ADAPTER PLATE IS ALIGNED ACCURATELY RELATIVE TO SAID HEAD, A GENERALLY CIRCULAR SEALING PLATE DISPOSED WITHIN SAID CYLINDER AND ESTABLISHING A FLUID TIGHT SEAL THEREWITH TO PREVENT FLUID WITHIN THE CYLINDER FROM COMING INTO CONTACT WITH SAID SPACED OPENINGS.