Compressor control system

Claim 1

IN COMBINATION, A RECEIVER FOR COMPRESSED GAS, A COMPRESSOR CONNECTED TO SAID RECEIVER TO DELIVER GAS THERETO, SAID COMPRESSOR BEING OF THE RECIPROCATING TYPE INCLUDING A PISTON RECIPROCATING IN A CYLINDER, AN INLET VALVE FOR THE CYLINDER AND AN EXHAUST VALVE FOR THE CYLINDER, AND ENGINE DRIVING SAID COMPRESSOR, PRESSURE RESPONSIVE MEANS FOR UNLOADING SAID COMPRESSOR PROPORTIONATELY IN RESPONSE TO A CONTROLLING PRESSURE, PRESSURE RESPONSIVE MEANS FOR OPERATING THE ENGINE THROTTLE TO VARY THE ENGINE SPEED IN RESPONSE TO VARIATIONS IN SAID CONTROLLING PRESSURE, MEANS FOR SUPPLYING SAID CONTROLLNG PRESSURE INCLUDING MEANS FOR DELIVERING FLUID UNDER PRESSURE TO A CONTROL LINE, SAID FLUID SUPPLYING SAID CONTROLLING PRESSURE, CONTROL MEANS CONNECTED IN PRESSURE RESPONSIVE COMMUNICATION WITH SAID RECEIVER FOR VARYING SAID CONTROLLING PRESSURE IN ACCORDANCE WITH SAID RECEIVER PRESSURE, CONDUIT MEANS CONNECTING SAID CONTROL LINE TO SAID UNLOADING MEANS FOR DELIVERING SAID CONTROLLING PRESSURE THERETO, MEANS FOR DELIVERING SAID CONTROLLING PRESSURE TO SAID ENGINE SPEED VARYING MEANS, CONTROL MEANS BEING RESPONSIVE TO INCREASES IN RECEIVER PRESSURE TO VARY SAID CONTROLLING PRESSURE IN A DIRECTION WHICH ACTUATES SAID UNLOADING MEANS TO UNLOAD SAID COMPRESSOR AND WHICH ACTUATES SAID THROTTLE OPERATING MEANS TO DECREASE THE ENGINE SPEED, SAID CONTROL MEANS INCLUDING A PILOT VALVE MEANS FOR REGULATING THE RATE OF FLOW THROUGH SAID CONTROL LINE TO VARY THE FLUID PRESSURE IN SAID CONTROL LINE, SAID PIVOT VALVE HAVING A CONTROL CHAMBER IN PRESSURE RESPONSIVE COMMUNICATION WITH SAID RECEIVER, AND A SELECTOR VALVE CONTROLLING FLUID FLOW FROM SAID CONTROL LINE TO SAID PILOT VALVE AND SAID ENGINE THROTTLE OPERATING MEANS, SAID SELECTOR VELVE HAVING ONE SELECTIVE POSITION IN WHICH SAID CONTROL LINE IS CONNECTED TO BOTH SAID PILOT VALVE AND SAID THROTTE OPERATING MEANS.