Patent ID: 9649418
Date: 2017-05-16
CPC Classifications: A61M,F04B,F17D,Y02A,Y10T

Claim:
1. A pump cassette comprising: a housing; a first reciprocating membrane pump in the housing having a first pump inlet and a first pump outlet, the first pump inlet in valved fluid communication with a first fluid port in the housing; a second reciprocating membrane pump in the housing having a second pump inlet connected to a second fluid port in the housing and a second pump outlet in valved fluid communication with the first pump inlet; a third reciprocating membrane pump in the housing having a third pump inlet connected to a third fluid port in the housing and a third pump outlet in valved fluid communication with the first pump outlet; a fourth reciprocating membrane pump in the housing having a fourth pump inlet in valved fluid communication with the first fluid port in the housing, and a fourth pump outlet in valved fluid communication with a fifth fluid port in the housing; a mixing chamber in the housing having an inlet in valved fluid communication with the first pump outlet and an outlet in valved fluid communication with a fourth fluid port in the housing; a first conductivity sensing flow path arranged to connect the first pump outlet with a first conductivity sensor apparatus; and a second conductivity sensing flow path arranged to connect the outlet of the mixing chamber with a second conductivity sensor apparatus; wherein the valved fluid communication comprises membrane-based valves, each valve having a flexible membrane, one side of which is configured and positioned to interrupt fluid flow through the valve upon application of pressure to an opposing side of the membrane.