Means for unloading and controlling compressor units

Claim 1

A COMPRESSOR UNIT FOR SUPPLYING AND MAINTAINING A COMPRESSED WORKING FLUID UNDER PREDETERMINED SUPERATMOSPHERIC PRESSURE AND COMPRISING A COMPRESSOR, A WORKING FLUID INTAKE CONDUIT IN FLOW COMMUNICATION WITH SAID COMPRESSOR, A THROTTLE VALVE IN SAID INTAKE CONDUIT MOVABLE FROM A FIRST THROTTLE POSITION TO A SECOND FULLY OPEN POSITION AND VICE VERSA, A COMPRESSED WORKING FLUID RECEIVER, A COMPRESSED WORKING FLUID DELIVERY CONDUIT LEADING FROM THE COMPRESSOR TO SAID RECEIVER, A CHECK VALVE IN SAID DELIVERY CONDUIT, A VENT PASSAGE COMMUNICATING WITH THE DELIVERY CONDUIT BETWEEN THE COMPRESSOR AND SAID CHECK VALVE, A VENT VALVE IN SAID VENT PASSAGE MOVABLE FROM A FIRST OPEN POSITION TO A SECOND CLOSED POSITION AND VICE VERSA, SPRING MEANS ARRANGED FOR MOVING SAID THROTTLE VALVE AND SAID VENT VALVE TO SAID FIRST POSITIONS FOR UNLOADING THE COMPRESSOR, AND WORKING FLUID PRESSURE RESPONSIBLE MEANS ARRANGED FOR MOVING THE THROTTLE VALVE AND THE VENT VALVE TO SAID SECOND POSITIONS FOR LOADING COMPRESSOR.