Medical infusion system

Claim 1

A pump for use in a medical infusion system for pumping fluid or semi-solids from an upstream portion of the infusion system to a downstream portion thereof, said pump comprising, conduit means, means for supporting said conduit means for extending between the upstream and downstream portions of the system, first constricting means for selectively restricting and opening said conduit means at a first location thereof, second restricting means for selectively restricting and opening said conduit means at a second location thereof spaced from said first location, third restricting means for selectively restricting and opening said conduit means at a third location thereof between said first and second restricting means to displace a predetermined volume in said conduit means, and means for operating said first, second and third restricting means in a sequence such as to pump fluids or semi-solids in said conduit means, said conduit means including a rigid section positioned between said first and second locations and defining a pumping cavity, said rigid section having a window therein, a flexible diaphragm extending across said window and being impermeable to the passage of fluid or semisolids therethrough, said third restricting means being engaged with said diaphragm, said operating means including drive means for providing incremental movement of said third restricting means to control incrementally the pumping of fluids or semi-solids said rigid section of said conduit means being of substantially tubular configuration, said diaphragm being formed in part by a relatively flexible sleeve positioned coaxially of said rigid section and extending over said window therein whereby said diaphragm comprises the portion of said flexible sleeve extending over said window.