Variable capacity reciprocating pump

Claim 1

A VARIABLE-CAPACITY RECIPROCATING PUMP COMPRISING: AN ELONGATED BASE MEMBER; A FIXED ABUTMENT ON ONE END OF SAID BASE MEMBER; AN ADJUSTING MEMBER CONNECTED TO SAID FIXED ABUTMENT; A CYLINDER HAVING AN OPEN AND A CLOSED END; MEANS CONNECTING SAID ADJUSTING MEMBER AND CYLINDER FOR RELATIVE LONGITUDINAL MOVEMENT THEREBETWEEN; A PISTON HAVING A HEAD SLIDABLY MOUNTED IN SAID CYLINDER; MEANS ON THE OTHER END OF SAID BASE MEMBER TO RECIPROCATE SAID PISTON; A SUPPLY AND DISCHARGE CONDUIT COEXTENSIVE WITH SAID CYLINDER; A COMBINED INLET AND OUTLET PORT ADJACENT THE CLOSED END OF THE CYLINDER OF CONNECTING SAID CYLINDER WITH SAID CONDUIT; A BY-PASS PORT INTERMEDIATE SAID CLOSED AND OPEN END OF SAID CYLINDER CONNECTING SAID CYLINDER WITH SAID CONDUIT; A CHECK VALVE POSITIONED IN SAID CONDUIT ON THE OUTLET SIDE OF SAID COMBINED INLET AND OUTLET PORT; AND A CHECK VALVE POSITIONED IN SAID CONDUIT BETWEEN SAID COMBINED INLET AND OUTLET PORT AND SAID BY-PASS PORT, THE CAPACITY OF SAID PUMP BEING ADJUSTABLE BY MOVEMENT OF SAID CYLINDER RELATIVE TO SAID LAST MENTIONED MEANS.