Device for Checking Acuteness of Injection Needle Point and Test Methodology

The paper presents a designed device for checking acuteness of injection needle point and development of methodology for conducting corresponding tests. Basic information on disposable injection needles including their purpose, structural elements and requirements for the state of their points. The paper describes a standard method for checking acuteness of injection needle point which is based on measuring maximum force for piercing a high-pressure polyethylene film of a certain thickness by an injection needle during its translatory motion at a given speed. A description is given of the design and operating principle of the developed device that implements this method for checking acuteness of injection needle points. Main provisions of the developed methodology for conducting these tests including sequence and content of actions during their execution have been set out in the paper. Results of the experiments on verification of acuteness in injection needle points of four-diameter confirm practical use validity of the developed device and methodology for conducting corresponding injection needle tests. The obtained oscillograms on changes in the force acting on a needle in the process of polyethylene film piercing are highly informative and that makes it possible to investigate in detail specific features at all stages of the process being studied, including both the stage of film piercing by a test needle and the subsequent stage of removing it from the contact with the film.