Check valve tester

Claim 1

A CHECK VALVE TESTER COMPRISING A SOCKET HAVING A THROUGH BORE FOR RECEIVING THE INLET END OF A CHECK VALVE AND RESILIENT RINGS IN SAID BORE FORMING AN AIR TIGHT SEAL WITH THE EXTERIOR OF SAID CHECK VALVE, AN AIR CONDUIT EXTENDING FROM SAID BORE IN COMMUNICATION WITH SAID INLET END OF SAID CHECK VALVE, AN INTERMITTENTLY OPERATING AIR PUMP CONNECTED TO ONE END OF SAID CONDUIT FOR APPLYING POSITIVE AIR PRESSURE THROUGH SAID CONDUIT TO OPEN SAID CHECK VALVE, SAID PUMP INCLUDING A HOLLOW CASING FORMING A WORKING CHAMBER, AN ELECTRICAL RESISTANCE FILAMENT IN SAID CASING AND ENERGIZABLE FOR HEATING AND EXPANDING THE AIR IN SAID CHAMBER TO PRODUCE SAID POSITIVE PRESSURE IN SAID CONDUIT, AND A VENT CONNECTED TO SAID CASING BY SAID CONDUIT AND HAVING A RESISTANCE ORIFICE FOR SLOWLY EXHAUSTING AIR TO THE ATMOSPHERE FROM SAID CHAMBER UNDER SAID POSITIVE PRESSURE, A MANUALLY CLOSED SWITCH FOR ENERGIZING SAID FILAMENT, AND A GAUGE CONNECTED TO SAID CONDUIT FOR DETERMINING WHETHER THE OPENING PRESSURE OF SAID CHECK VALVE UNDER SAID POSITIVE PRESSURE FALLS WITHIN PREDETERMINED MINIMUM AND MAXIMUM VALUES RELATIVE TO A STANDARD REFERENCE PRESSURE, SAID GAUGE INCLUDING A MANOMETER TUBE DIRECTLY CONNECTED TO SAID CONDUIT CONTAINING A FLUID MOVABLE IN RESPONSE TO SAID POSITIVE PRESSURE, ELECTRIC LIGHT MEANS CONNECTED TO SAID MANOMETER AND ENERGIZABLE UPON CONTACT WITH SAID FLUID FOR INDICATING BOTH SAID MINIMUM AND MAXIMUM VALUES, AND THE OUTLET END OF SAID CHECK VALVE BEING OPEN TO SAID STANDARD REFERENCE PRESSURE.