A cassette (1) that isinsertable into an infusion pump fordelivery of a fluid to a subject thathas a housing with two ends for holdingflexible tubing (75) throughwhich the fluid is directed. The housinghas an open area exposing thetubing, which engages a pumpingmechanism when inserted into an infusionpump. An anti-flow valvemechanism (100) associated with thetubing or the cassette and present eitherin, on or near the housing ismade up of a piston (103/105) andspring (110), where the spring biasesthe piston against the tubing to preventfluid flow.
