CYLINDER-PISTON UNIT SUITABLE FOR STORING INJECTION SOLUTIONS FOR A NEEDLE-FREE INJECTOR AND METHOD FOR THE BUBBLE-FREE AUTOMATIC OR MANUAL FILLING OF THE CYLINDER-PISTON UNIT, ALSO UNDER ATMOSPHERIC PRESSURE

摘要

The invention relates to a cylinder-piston unit (1) which is resistant to pressure, vapour and oxygen for a needle-free injector. Said unit comprises a chamber (3) which is arranged in a cylinder (2) and is used to accommodate an injection solution (4) in a durable and sterile manner, a front wall (5) having at least one nozzle bore or an outlet element (6), a pressure-stable exterior cylinder (13) and a piston (7) which is pressure, vapour and oxygen resistant and which is arranged in a displaceable manner in the chamber (3). According to the invention, the chamber (3) consists of a first chamber (8) and a second concentric chamber (9), the cross-section of the first chamber (8) being greater than the cross-section of the second chamber (9) and each nozzle bore or each outlet element (6) is sealed in a sterile manner by a membrane (26, 27) which is vapour and oxygen resistant and which opens when subjected to excess pressure. The invention also relates to a method for automatically or manually filling the cylinder-piston unit (1), also under atmospheric pressure.