Infusion pumping apparatus

Claim 1

A rotor cassette for pumping infusion fluid through an infusion tube, said cassette comprising: a housing having a rotor cavity formed in the outside surface thereof with a working surface which is a portion of a cylinder and also having inlet and outlet passages formed in the outside surface thereof extending through said housing from the outside surface of said housing to two spaced points on said cylindrical working surface, said rotor cavity and said inlet and outlet passages adapted to contain an infusion tube running through said inlet and outlet passages and along said cylindrical working surface; a rotor body mounted for rotation within said rotor cavity on an axis which coincides with the axis of said cylindrical working surface and having (a) a plurality of fingers each having a leading edge smoothly curved across its thickness joining a peripheral edge smoothly curved across its thickness through a connecting surface smoothly curved along its length and across its thickness, and (b) an inner wall adjacent the end wall of said rotor cavity and spaced axially from said rotor fingers, the outside surfaces of said rotor fingers projecting slightly beyond the outside surface of said housing and each of said outside surfaces of said rotor fingers sloping down toward the trailing edge of said rotor fingers; and a plurality of rollers mounted at the periphery of said rotor body between said inner wall of said rotor body and said rotor fingers for rotation about axes parallel to the rotation axis of said rotor body, said rollers spaced from said cylindrical working surface to squeeze an infusion tube running along said cylindrical working surface between said rollers and said cylindrical working surface.