Needle-less injection syringe has cavity with inner wall projection to retain end plug expelled by pressurised injection fluid

摘要

The syringe consists of a body (2) with an inner cylindrical reservoir (3) for the injection fluid, closed by two movable end plugs, and an end receptacle (7) with at least one peripheral injection duct (8) and a cavity (10) to receive the downstream plug (5) when it is expelled by the pressurised injection fluid. The cavity has an inner wall projection to retain the plug and prevent any rebound; the projection being made by two adjoining truncated conical surfaces, a series of cones, a spiral or other shape.