Pipe testing apparatus

Claim 1

IN A PIPE TESTING APPARATUS HAVING LONGITUDINALLY SPACED PACKERS, AND A VALVE ASSEMBLY FOR CONTROLLING THE INTRODUCTION OF TEST FLUID BETWEEN SAID PACKERS, THE IMPROVEMENT RESIDING IN SAID VALVE ASSEMBLY, INCLUDING: (A) A VALVE HOUSING HAVING A LONGITUDINAL BORE THEREIN WITH A COUNTERBORE TO FORM AN ANNULAR LATERAL SHOULDER, (B) A CYLINDRICAL VALVE SEAT HAVING A LATERAL FLANGE WITH ITS OUTER PORTION DISPOSED IN ENGAGEMENT WITH SAID SHOULD AND ITS INNER PORTION DISPOSED INWARDLY OF SAID SHOULDER TO FORM AN ANNULAR VALVE SEAT SURFACE, (C) A RETAINER CAP REMOVABLY MOUNTED IN SAID COUNTERBORE AND ENGAGING SAID LATERAL FLANGE TO RETAIN SAME IN ENGAGEMENT WITH SAID SHOULDER, (D) SAID RETAINER CAP HAVING A LONGITUDINAL BORE WITH AN ANNULAR RECESS FOR RECEIVING THE CYLINDRICAL PORTION OF SAID VALVE SEAT, (E) A VALVE ELEMENT HAVING A GUIDE TUBE EXTENDING INTO SAID LONGITUDINAL BORE OF SAID RETAINER CAP AND A LATERALLY EXTENDING VALVE SURFACE ADAPTED TO ENGAGE SAID VALVE SEAT SURFACE TO CLOSE FLUID FLOW THROUGH SAID LONGITUDINAL BORE, AND (F) SAID VALVE SEAT BEING FORMED OF A PLASTIC RESILIENT MATERIAL WHICH IS SOFTER THAN SAID VALVE SURFACE ON SAID VALVE ELEMENT FOR SEALINGLY ENGAGING EACH OTHER WHEN SAID VALVE ELEMENT IS IN THE CLOSED POSITION.