Eccentric plug valve having a limit stop and method of manufacture thereof

Claim 1

IN AN ECCENTRIC TYPE PLUG VALVE, THE COMBINATION COMPRISING, A HOLLOW BODY HAVING INLET AND OUTLET OPENINGS AND A FLOW PASSAGE THEREBETWEEN, A PLUG EXTENDING ACROSS SAID PASSAGE AND JOURNALLED IN SAID BODY FOR ROTATION ABOUT AN AXIS, SAID BODY BEING A MACHINED CASTING SUBSTANTIALLY SYMMETRICAL ABOUT A PARTING PLANE AND HAVING AN INNER, ARCUATE SEAT SURFACE SURROUNDING ONE OF SAID OPENINGS AND ECCENTRICALLY DISPOSED RELATIVE TO SAID AXIS, SAID PLUG BEING A MACHINED CASTING HAVING AN ECCENTRIC PORTION WITH AN ARCUATE FACE ECCENTRICALLY DISPOSED RELATIVE TO SAID AXIS, SAID FACE AND SAID SEAT SURFACE HAVING SEALING CONTACT WHEN SAID PLUG IS ROTATED TO BRING THEM INTO MUTUAL ENGAGEMENT, SAID BODY HAVING AN INTERIOR, INTEGRAL, CAST, ARCUATE MEASURING SPUD SURFACE, SAID SPUD SURFACE TERMINATING AT ONE EDGE IN A FIRST SIDE SURFACE LYING IN SAID PARTING PLANE, SAID FACE TERMINATING AT ONE EDGE IN A SECOND SIDE SURFACE RADIAL THERETO AND LYING ON A CENTRAL PLANE OF SAID PLUG CASTING, SAID FIRST AND SECOND SIDE SURFACES BEING MUTUALLY ENGAGED TO LIMIT ROTATION OF SAID PLUG WHEN SAID ECCENTRIC PORTION HAS BEEN RETRACTED FROM SAID SEAT TO A POINT WHERE IT PRESENTS MINIMUM RESISTANCE TO FLOW THROUGH SAID PASSAGE.