Integrated RFID Aperture and Washing Chamber Shielding Design for Real-Time Cleaning Performance Monitoring in Healthcare Laundry System

A preliminary design of integrated RFID aperture and washing chamber shield for real-time cleaning monitoring in healthcare laundry system is proposed. The installation of RF based monitoring system includes sewing attachment of the RFID tags to the healthcare clothes and the setting up of RFID shield, aperture, and reader to the washing tub, and open area of the washing machine. During the wash, the clothes circulation was tracked by filtered RF transmission between the tags and reader. Software was designed to evaluate the circulation e.g. rotating, sinking, and floating of the various clothes in the batch and update the circulation level in real-time. Two types of conventional healthcare washing machines i.e. agitator and pulse flow were selected for the experiments. The Received Signal Strength Indicator (RSSI) was evaluated on each combination of RFID design, washing condition and clothes circulation level. The cleaning performance of each combination of washing condition and circulation was evaluated by using Microbiological (RODAC plate count) testing. Design of experiments (DOE) methodology of 2⁵ was used to examine the relationship between washing circulation and cleaning performance on representative healthcare laundry machines. 5 trials were repeated at each experimental condition before the repeatability of RSSI was examined. The design providing best repetitive RSSI is presented.