Patent ID: 8480617

Claim:
A needle-free injection device for needle-free injection of a medium, comprising: an ampoule unit including a main body filled with an injectable substantially gas-free medium, a nozzle positioned at an axially longitudinal end of the ampoule unit that defines an outlet for ejecting the medium, a jacket completely surrounding the main body in a longitudinal axial direction of the ampoule unit and partially surrounding the nozzle so that the nozzle abuts an inner wall of the jacket in a form-fitting manner, the jacket exerting compressive forces on the main body to at least counterbalance the internal stresses in the main body, and a hollow plunger rod through which the main body is able to be filled, the hollow plunger rod including at least one pinched portion that forms a seal to seal the medium within the main body after the main body is filled.