Safety syringe

Three versions of a safety syringe are disclosed which can be used as a Pressure Sampler syringe, an Aspiration Sampler syringe, or a regular Hypodermic Injection syringe. The device has a manually retractable needle which withdraws to inside the syringe after use; thus, protecting the user from accidental stabbing by an exposed used needle. The syringe plunger can still function to expel entrained fluids after the used needle is retracted to the "safe" position, which allows the syringe to be used as a blood gas analysis sampler. Additionally the sampler versions of the syringe will completely seal the sampled fluid from the atmosphere, thus assuring no contamination of the sample. The device consists of three basic parts, a retractable needle and seal assembly, a standard syringe barrel, and a modified plunger which stores the retracted needle.