Introduction for Medical Disposable Syringe with Needle

What types of syringes are there?
Disposable sterile syringes: usually composed of a body, a cone, a piston and a core rod. The body is generally made of polymer materials, and the piston is generally made of natural rubber. Provided sterile.
Needle-free syringes: usually composed of a syringe, a resetter, a drug extraction needle, an ampoule, an adapter or other parts. It does not contain liquid medicine. It relies on mechanical, electrical or other energy sources to perform its functions. The syringe and resetter are provided non-sterile and reusable; the drug extraction needle, ampoule and adapter are provided sterile and disposable.
Glass syringes: usually composed of three parts: a jacket, a core and a cone. Generally made of borosilicate aluminum glass. It can be reused after cleaning and sterilization, but it is rarely used now.
What is the working principle of the syringe?
Disposable sterile syringes and glass syringes: Using the atmospheric pressure principle, before the syringe absorbs the liquid medicine, push the piston to the bottom with force to exhaust the air inside, and then the needle of the syringe is inserted into the liquid medicine. When the piston is gradually pulled up, the pressure at the front end of the piston is less than the atmospheric pressure, while the pressure on the medicine wave surface is equal to the atmospheric pressure. Under the action of the pressure difference, the liquid medicine is sucked into the syringe. Needle-free syringes: Needle-free syringes use the principle of pressure jet to complete the subcutaneous injection of liquid medicine, that is, the pressure generated by the pressure device inside the needle-free syringe pushes the liquid medicine in the medicine tube through the micropores to form an extremely fine liquid medicine column, so that the liquid medicine instantly penetrates the human epidermis and reaches the subcutaneous part. The liquid medicine is absorbed in the subcutaneous part in the form of a diffuse shape with a diameter of 3-5 cm.