Patent ID: 8888470

Claim:
A pumping cassette comprising: a housing comprising at least one membrane pump for pumping liquid, the membrane pump comprising a pumping chamber and an actuation chamber that is separated from the pumping chamber by a flexible membrane, the pumping chamber comprising at least two flowpaths for the inflow or outflow of liquid; a first liquid port on the housing, the first liquid port being in fluid communication via one or more pump valves in the housing with one or more ports of the pumping chamber; and a venting port on the housing, the venting port being in fluid communication via a vent valve in the housing with a vent on the housing, wherein the venting port, vent valve and vent are fluidically isolated from the first liquid port, the one or more pump valves, and the pumping chamber of the pump, and the first liquid port and the venting port are adapted to make separate fluid connections with a reservoir external to the pumping cassette, and wherein the first liquid port is configured to receive liquid from the reservoir, and the venting port is configured to make a venting connection with the reservoir.