Abstract: An infusion device for dispensing drugs and other fluids at controlled rates over extended time periods. The device includes a syringe section and a power section that are connected together in use, the power section having a casing defining a first chamber containing a vacuum-stable viscous liquid and a second chamber under partial vacuum. A metering passage extends between the two chambers, and a piston is slidably received in the casing and constitutes a movable wall of the first chamber so that as the viscous liquid gradually flows through the metering passage into the second chamber the piston retracts slowly to cause fluid to be discharged from the syringe.

Abstract: The pump (10 or 150) is adapted to deliver liquid (24 or 166) to an individual. The pump comprises a syringe section (12 or 152) including a syringe barrel (18 or 160) having a nozzle (20 or 162) at one end and a syringe piston (22 or 170) in the barrel (18 or 160), an intermediate section (14 or 154 and 156) mounting a piston rod (46 or 265) for axial movement thereof, one end of the rod (46 or 265) being associated with the piston (22 or 170) for acting on the piston (22 or 170), and a drive section (16 or 158) at the other end of the pump (10 or 150) including a gas spring (113 or 300) associated with the other end of the piston rod (46 or 265) for acting on same to move the piston rod (46 or 265) which moves the syringe piston (22 or 170) to cause liquid to be delivered from the syringe barrel (18 or 160).