A fluid delivery system in which the pressure platen for a fluid conduit is fixedly mounted to the pump and the pumping mechanism is movable in relation to the platen (32) to control the force exerted on the conduit. A moving system comprising a four-bar linkage (48, 50, 52, 54) retains the movable pumping mechanism in a predetermined orientation to the conduit through the mechanism's range of movement. The pumping mechanism is spring (63) loaded towards the conduit (30). The peristaltic fingers (22) of the pump mechanism are located in guides with the drive means for those fingers rigidly mounted to that guide. Should the movements of one or more fingers through the respective guide be prevented, the drive means will be stopped from movement and the pumping mechanism will stall rather than back off and allow free flow.