FIELD: medical equipment, in particular, prolonged supplying of liquid. SUBSTANCE: osmotic pump has housing 2, supply chamber 5 positioned within housing 2 and separated from osmotic salt chamber 7 by movable impermeable pressure-sensitive device, such as piston 6 or flexible membrane. Osmotic salt chamber 7 is separated from osmotic liquid source, such as osmotic liquid chamber 12, by semi-permeable membrane 96 mounted in piston 9. Liquid barrier isolates osmotic salt chamber 7 from osmotic liquid chamber 12 and may be deactivated, when piston is required for operation. Liquid barrier may be made in the form of foil sheet 10 and may be deactivated by destruction (rupture) or in the form of piston with liquid bypass channel. Osmotic pump is deactivated by charging chamber 5 with agent supposed for patient. In other versions deactivation is provided by displacement of plunger in case of manual control, or by releasing blocking device, which retains plunger in required position, in case plunger is preliminarily shifted. EFFECT: increased efficiency, simplified construction and enhanced reliability in operation. 14 cl, 10 dwg
