Abstract: A method and apparatus for determining leakage, particularly of valves, in a pump assembly. A pump assembly (20) includes a primary valve (34) and a secondary valve (36), which may be selectively activated to control the source of fluid input to the pump assembly. The pump assembly also includes an inlet valve (42) and an outlet valve (50) disposed on each side of the pumping chamber (46). Downstream of the outlet valve is disposed a pressure sensor (54), which produces a signal indicative of the pressure of fluid within the pump assembly at that point. Leakage in the inlet or outlet valves is detected in the inlet or outlet valves by filling the pumping chamber with fluid, closing the inlet and outlet valves, and equalizing the pressure in the pump assembly distal to the inlet valve. After the pressure has been equalized, the outlet valve is opened and a reference pulse is determined as a function of the signal produced by the pressure sensor.

Abstract: Risk of hydrodynamic pressure noise interference with a valve leakage test conducted upon a plurality of valves within a pump assembly is minimized. A pressure sensor within the pump assembly produces a signal indicative of hydrodynamic pressure in fluid distal of an outlet valve of the pump. The signal produced by the pressure sensor is input to a microcontroller that controls the pump assembly. Prior to conducting the valve leakage test, the hydrodynamic pressure level of the fluid is sampled at a frequency that is at least twice that of the hydrodynamic noise. The microcontroller determines if a maximum of the samples of the hydrodynamic pressure level taken during a data interval is above a predetermined threshold. If so, the valve leakage test is suppressed until the maximum pressure level is below the predetermined threshold during a successive data interval.

Abstract: Apparatus and method for determining leakage, particularly of valves, in a pumping cassette. A cassette (70) includes a primary valve (34) and a secondary valve (36), which may be selectively activated to control the source of fluid input to the cassette. The cassette also includes an inlet valve (48) and an outlet valve (56) disposed on each side of a pumping chamber (52). Downstream of the outlet valve is disposed a pressure sensor (60) which produces a signal indicative of the pressure of fluid within the cassette at that point. The cassette also includes an air-in-line sensor (40), disposed between a manifold line (38) that connects the primary and secondary valve in fluid communication with an air trap reservoir (44). Leakage in the inlet or outlet valves is detected by closing both valves, pressurizing fluid in the pumping chamber for a predetermined period of time, and then opening the outlet valve.

Abstract: A driver for use in an infusion pumping cassette having an elongated valve actuator which operates a valve controlling the flow of fluid through the cassette, a bracket having a first arm pivotally secured to one end of the valve actuator and a second arm, a cam driveably engaging the second arm, a motor which drives the cam and a positioner which monitors the rotational position of the cam.