Automatic shut-off device for pumping wells

Claim 1

AN AUTOMATIC SHUT-OFF CONTROL FOR AN OIL WELL PUMPING SYSTEM, SAID OIL WELL PUMPING SYSTEM HAVING A PRIME MOVER FOR ACTUATING A RECIPROCATING BOTTOM-HOLE PUMP MECHANISM OF THE TYPE THAT PRODUCES PULSATING FLUID FLOW THROUGH A CONDUIT OUT OF SAID WELL, SAID SHUTT-OFF CONTROL COMPRISING, IN COMBINATION: A PLUNGER MEMBER RESPONSIVE TO FLOW OF FLUID THROUGH SAID CONDUIT; A TRANSFORMER HAVING A PRIMARY AND A SECONDARY WINDING, SAID WINDINGS SUPPORTED IN PROXIMITY TO EACH OTHER; MEANS SUPPLYING ALTERNATING ELECTRICAL CURRENT TO SAID PRIMARY WINDING; A CORE MEMBER ACTUATED BY SAID PLUNGER AND MOVABLE WITHIN SAID WINDING, SAID CORE MEMBER VARYING THE MUTUAL INDUCTANCE BETWEEN SAID WINDINGS ACCORDING TO THE POSITION THEREOF RELATIVE TO SAID WINDING WHEREBY THE MUTUAL INDUCTANCE AND THEREBY THE VOLTAGE INDUCED IN SAID SECONDARY WINDING AT ANY INSTANT IS DETERMINED BY THE POSITION OF SAID PLUNGER WHICH IN TURN IS DETERMINED BY THE QUANTITY OF FLUID FLOWING THROUGH SAID CONDUIT FROM SAID WELL; A RELAY MEANS HAVING CONTINUITY WITH SAID SECONDARY WINDING, SAID RELAY MEANS HAVING SWITCH MEANS FOR CONTROLLING POWER SUPPLIED TO SAID PRIME MOVER; AND TIME DELAY MEANS WITH SAID RELAY MEANS WHEREBY SAID RELAY SWITCH IS ACTUATED AFTER A PREDETERMINED TIME TO DEENERGIZE SAID PRIME MOVER UPON THE CESSATION OF SAID PUSHING FLUID FLOW.