Patent ID: 8968232
Filing Date: 2015-03-03
Classification: A61F,A61M,F04B,G01K,G01M,G05D

Abstract:
1. A method for using a controller to control a fluidly actuated pumping cassette, the method comprising: opening an inlet valve on the cassette to fluidly connect a source of the liquid with at least one reciprocating positive-displacement pump on the cassette, each pump comprising: introducing a quantity of the liquid into the pumping chamber through the inlet valve; closing the inlet valve and fluidly isolating the pumping chamber; applying a known pressure to the actuation chamber; measuring a rate of pressure change in the pumping chamber or the actuation chamber; comparing the measured rate of pressure change with the controller to a pre-determined range of values; and determining that air is present in the pumping chamber if the measured rate of pressure change differs from the pre-determined range of values.