Dosing pump operating in opposite phases for dosing liquid or gaseous media

Claim 1

A PUMP OPERATING IN OPPOSITE DIRECTIONS FOR SUPPLYING LIQUID OR GASEOUS MEDIA, SAID PUMP HAVING A PAIR OF AXIALLY SPACED PISTONS, A HOUSING FOR SAID PISTONS, FLEXIBLE DIAPHRAGMS CONNECTING SAID PISTONS TO SAID HOUSING, AN OPERATING CHAMBER FOR EACH OF SAID PISTONS, AN INCOMPRESSIBLE MEDIUM SUPPORTING EACH OF SAID FLEXIBLE DIAPHRAGMS ON A SIDE THEREOF REMOTE FROM SAID OPERATING CHAMBER TO FORM AN ANNULAR SEALING CHAMBER WHEREIN THE IMPROVEMENT COMPRISES A SLIDING MEMBER JOURNALLED IN SAID HOUSING AND CONNECTING SAID PISTONS, SAID FLEXIBLE DIAPHRAGMS SEPARATING SAID OPERATING CHAMBERS AND EACH BEING CONNECTED ON ONE END TO THE ADJACENT END FACE OF SAID PISTON AND AT THE OTHER END TO THE ADJACENT HOUSING WALL, SAID PISTONS HAVING A REDUCED DIAMETER WITH RESPECT TO SAID SLIDING MEMBER, SAID SLIDABLE MEMBER WHEN OPERATIVE ENTERING SAID SEALING CHAMBER TO THEREBY DISPLACE SAID MEDIUM IN AN AMOUNT EQUAL TO THE CHANGE IN THE CONFIGURATION OF SAID CHAMBER WHEREBY THE NET VOLUME OF SAID CHAMBER REMAINS CONSTANT.