Throwaway hypodermic syringe - with rear piston for push rod and front piston with centre pier cable by pointed needle rear

摘要

A throwaway hypodermic syringe has the injection fluid enclosed between two elastomer pistons. A push rod can be engaged to the rear piston. The front piston has a thin centre which can be pierced by the sharp rear end of the needle. It is separated before use from the front part of the phial by an air space with a vent hole.