DEVICES AND METHODS FOR BODY FLUID FLOW CONTROL IN EXTRACORPOREAL FLUID TREATMENT
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Abstract
Disclosed are devices and methods for the control of body fluid flow in the extracorporeal treatment of body fluid. Body fluid flow through on of a body fluid flow circuit 10, 50, 60 100, or 250 is controlled by alternatingly applying vacuum pressure and positive pressure to the circuit through a pumping chamber 30, 51, 66, 102, or 200 coordinated with flow control valves 40, 42, 44, 62, 114, 116, 118, and 120 to effect a net downstream flow of body fluid through the circuit.
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Citations
59 Claims
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1-50. -50. (canceled)
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51. A body fluid treatment apparatus comprising:
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a body fluid pumping chamber containing a flexible membrane that is configured to draw body fluid into the pumping chamber under negative gaseous pressure on a gas side of the membrane and alternately to expel body fluid from the pumping chamber under positive gaseous pressure on the gas side of the membrane; a sensor that is configured to provide a flow rate signal representing the flow rate of body fluid flowing into the pumping chamber; and a control apparatus that is configured to pressurize the pumping chamber on the gas side of the membrane alternately with positive and negative gaseous pressure with reference to the flow rate signal by a) pressurizing the gas side with negative gaseous pressure and b) switching the gaseous pressure at the gas side from negative to positive upon determining that the flow rate into the pumping chamber has decreased in an amount that is predetermined to result from greater flow resistance as the pumping chamber reaches capacity at a desired cycle volume. - View Dependent Claims (52, 53, 54, 55, 56, 57, 58, 59)
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Specification