Simulation and Verification of Steam Sterilization of Medical Device Trays

Abstract

The sterilization of surgical instruments is essential in the medical field to prevent the transmission of germs, bacteria, and viruses. This can be achieved using an autoclave, a device that sterilizes instruments through the application of steam. In thisthesis, the processes of steam generation in the steam generator and its distribution within the sterilization chamber have been analysed numerically. This study included an in-depth review of relevant literature and standards to identify the worst-case scenario that could be simulated among multiple trays. It also examined the dynamics of evaporation-condensation, steam distribution within the autoclave, and the effective elimination of microorganisms from the instruments. This research leverages existing numerical studies in steam sterilization to evaluate their relevance and efficacy in real-time tray sterilization applications. These studies offer valuable insights into the crucial parameters and conditions necessary for achieving optimal sterilization results, including temperature, pressure, and cycle duration. Thermocouple readings taken at six locations within the tray closely aligned with the thermal simulation results, showing only a minimal deviation of 0.0084%. The average surface temperature of the Acetabular shell trials was recorded at 132.72°C which is requires for the deactivation of the microorganisms and the average pressure maintained during the sterilization phase is also stabilized to 3.2 bar using a user defined function. This study provides valuable insights that support the new product development phase by guiding the design of trays to enhance steam penetration and to minimize the necessity for comprehensive tray testing. This simulation technique demonstrates an actual use of simulation methods in the design process. By incorporating simulation from the beginning, companies can identify potential design defects before they happen, employ correction procedures more effectively, and progress towards actual manufacturing with more confidence. This entire developmental process also benefited by saving time and expenses and enhancing efficiency in the product's reliability.