NEEDLELESS HYPODERMIC JET INJECTOR DEVICE

摘要

A needleless, three-shot, variable dose jet injector (1) comprises a body portion (2) having a passageway (5) and a trigger (7), a cylinder portion (11) onto which a medicament vial (17) can be screwed in order to vary the dose to be applied and a piston head (16) movable within the cylinder portion (11) to move a plunger (15) into the vial (17). The vial (17) has a bore (20) containg the medicament which exits through an orifice (19) under pressure from a plug (21) moving under actuation from the plunger (15). The piston head (16) is caused to move by the release of gas from one (28) of three chambers in a gas capsule (27) through an exit port (43) into the passageway (5) due to the trigger (7) opening a valve (31). The passageway (5) is arranged so as to only align with the exit port and valve of one of the three chambers at a time, so that, by rotating the capsule (27), three shots of gas can be provided in a single capsule.