Automated Medical Sterilizer Design: Improving Third-World Medicine

Chosen International Medical Assistance in Erie, Pennsylvania recycles old medical sterilizers from the United States into sterilizers suitable for use in developing countries. Their sterilizer design is manually operated, utilizing a multiport valve for controlling fluid, i.e. steam, pathways within the sterilizer. In an effort to adapt to modern, automated systems and improve the efficiency of the system, an electrically driven design has been proposed. The design is based on research in modern sterilizer design, focusing on the four main stages of the sterilization process: presterilization, sterilization, exhaust, and dry. Generally, in the presterilization phase, the process begins by pressurizing the Jacket, the space between the Chamber and the outside of the sterilizer. This creates a 250°F thermal insulation around the chamber. Next steam enters the chamber, beginning the sterilization phase and cleansing microbial life from medical instruments within the chamber. Through the exhaust phase the steam then is evacuated from the chamber which depressurizes the chamber. Finally, filtered air is introduced into the chamber to dry the medical supplies of any residual moisture. In place of the multiport valve, a system of four solenoid valves is to be used for controlling the stages of the sterilization process. For feedback and decision-making purposes multiple pressure and temperature sensors are integrated into the design. Utilizing ladder logic, the system is to be controlled by a PLC (Programmable Logic Controller). For user accessibility an RGB LED is also to be used for indicating start, stop, and potential problems within the sterilizer. The four-solenoid valve design must be more cost efficient than the currently used multiport valve. This poster will outline the new four solenoid system design and its implementation.