Patent ID: 7325572

Claim:
A medical apparatus flow restrictor, comprising: a housing having an inlet and an outlet, and a fluid flow path defined through said housing between said inlet and said outlet; at least one pair of opposed restriction surfaces in contact with each other in an axial direction within said housing between said inlet and said outlet, a first one of said surfaces being carried on a first continuous rigid restriction device, the second one of said surfaces being carried on a second rigid restriction device that is continuous except for at least one opening therethrough, said opening being disposed in communication with said inlet and said outlet, said restriction devices defining outermost peripheral edges, said restriction surfaces disposed in said flow path such that fluid delivered to said inlet passes between said opposed restriction surfaces via said outermost peripheral edges of said restriction devices and said opening of said first continuous restriction device prior to flowing from said outlet; and wherein at least one of said restriction surfaces comprises a pattern of fluid passages formed into said surface, said passages having a size and shape and cooperating with said opposed restriction surface such that a desired flow rate of fluid is achieved through said restrictor.