Research Into Syringe

Design History

All of them have the same general features, including a barrel, plunger, needle, and cap. The barrel is the part of the hypodermic needle that contains the material that is injected or withdrawn. A movable plunger is contained within this tube. The width of the barrel is variable. Some manufacturers make short, wide tubes, and others make long, thin ones. The exact design will depend to some extent on how the device will be used. The end of the barrel to which the needle is attached is tapered. This ensures that only the desired amount of material will be dispensed through the needle. At the base of the barrel away from the needle attachment, two arms flare out. These pieces allow the needle user to press on the plunger with the thumb while holding the tube in place with two fingers. The other end of the barrel is tapered.

The plunger, which is responsible for creating the vacuum to draw up materials and then discharge them, is made of a long, straight piece with a handle at one end and a rubber plunger head on the other. The rubber head fits snugly against the walls of the barrel, making an airtight seal. In addition to ensuring an accurate amount of material is drawn in, the squeegee action of the plunger head keeps materials off the inner walls of the tube.
The needle is the part of the device that actually pierces the layers of the skin. Depending on how deep the injection or fluid extraction will be, the needle orifice can be thinner or wider, and its length varies. It can also be permanently affixed to the body of the syringe or interchangeable. For the latter type of system, a variety of needles would be available to use for different applications. To prevent accidental needle stick injuries, a protective cap is placed over the top of the needle when it is not in use.

How Products are Made. [Online Article] Syringe.

Available at: <http://www.madehow.com/Volume-3/Syringe.html#ixzz2GNJRY7Yl> [Accessed on 28th December 2012]