Solution pumping system including disposable pump cassette

A pump cassette for use with an associated pump driver having a reciprocable pump plunger and a plurality of valve actuators, said pump cassette comprising:

• a rigid cassette body;
• and
• elastomeric diaphragm means positioned in said cassette body,
• said cassette body and said diaphragm means together providing said pump cassette with a plurality of liquid inlets, at least one liquid outlet, a liquid flow path for joining said liquid inlets and outlet in fluid communication, and pump means operably driven by the pump plunger of said associated pump driver for pumping liquid from a selected one of said liquid inlets to said liquid outlet via said flow path,
• said cassette body and said diaphragm means together providing at least one downstream one of said liquid inlets with liquid flushing means so that liquid flow between upstream and downstream portions of said flow path at said one inlet flushes residual liquid from the region of said one liquid inlet, thereby avoiding mixture of incompatible liquids in said cassette.

A solution pumping system, comprising

• a pump driver, said pump driver including a reciprocable pump plunger, and a plurality of valve actuators;
• and
• a pump cassette removably positionable in operative association with said pump driver,
• said pump cassette including a cassette body comprising a front body member and a juxtaposed rear body member, and an elastomeric diaphragm positioned between said front and rear body members,
• said front body member defining together with said diaphragm a plurality of liquid inlets, at least one liquid outlet, a liquid flow path for joining said liquid inlets and outlet in fluid communication, and pump means operably driven by the pump plunger of said associated pump driver for pumping liquid from a selected one of said liquid inlets to said liquid outlet via said flow path, each of said inlets and outlets comprising a liquid passage defined by said front body member and terminating in a valve seat,
• said rear body member defining a plunger opening at said pump means for operative engagement of said reciprocable pump plunger with said diaphragm means for operating said pump means, said rear body member further defining a plurality of valve actuator openings at respective ones of said liquid inlets and outlets for operative engagement of respective ones of said valve actuators with said diaphragm for selectively urging said diaphragm against said valve seats of said inlets and outlets for selecting controlling liquid flow therethrough,
• said front body member and said diaphragm together providing a plurality of downstream ones of said liquid inlets with liquid flushing means so that liquid flow between upstream and downstream portions of said flow path at each of said ones of said liquid inlets flushes residual liquid from the region of the liquid inlet, thereby avoiding mixture of incompatible liquids in said cassette, each of said liquid flushing means comprising at least one bypass passage means of said liquid flow path extending adjacent to the valve seal of the respective one of said liquid inlets.