Patent attributes
A pump cassette comprising an outer flexible membrane covering flowpaths, valve chambers and pump chambers of the cassette is designed to be actuated by a control gasket on a base unit arranged to move designated valve and pump portions of the cassette membrane. The gasket valve control or actuation region is at least partially bounded by a vacuum channel facing the outside of the gasket so that a constant vacuum can be applied between the gasket valve control or actuation region and the adjacent portion of the cassette membrane. An improved version of the vacuum channel comprises a flexible inner wall of the vacuum channel flexes or partially collapses away from the cassette valve seat, while still maintaining patency of the vacuum channel during the application of negative pressure on the gasket valve actuation region to open the cassette valve.
