Abstract: An infusion pump, suitable for medical applications, has a movable carriage which is arranged gradually to depress the plunger of a syringe. The carriage moves along a fixed rod at a rate determined by the rotation of a lead screw. Any excess pressure in the infusion line produces a back-pressure on the plunger which causes an axial force to be exerted on the carriage and thus on the lead screw. When this force exceeds a predetermined value, indicative of an occlusion of he infusion line, the lead screw will move axially so compressing a spring and causing a clutch to become decoupled, causing infusion to cease and an alarm to sound.

Abstract: An apparatus for delivering fluid at a controlled rate of flow wherein fluid is forced from a container by the piston of a vacuum cylinder. A flow restricting valve is provided, either at the output of the container or at the output of a second cylinder which is coupled to the piston of the vacuum cylinder.