A wireless logger measures physical parameters such as pressures and temperatures anywhere in the chamber without any need of wiring. In the present study, the air removal effects of vacuum pulses were evaluated using the logger in the free chamber space of the prevacuum autoclave without sensor ports. Evaluations using the logger were performed in the presence of one vacuum pulse, two vacuum pulses, three vacuum pulses and four vacuum pulses, respectively. The sterilization phase was programmed as 134.0°C for 3.5 minutes. The F₀ values were computed using the actual steam temperature and the value of saturated steam temperature corresponding to the measured pressure, respectively. Moreover, the residual air volume was estimated at 25°C and 1013 mbar absolute in the free chamber space. The F₀ value by actual temperature was lower than the F₀ value by calculated temperature by 31.5 in one vacuum pulse mode, 19.0 in two vacuum pulse mode, 16.6 in three vacuum pulse mode and 13.8 in four vacuum pulse mode, respectively. The estimated residual air volumes (m³) were 0.086 in one vacuum pulse mode, 0.032 in two vacuum pulse mode, 0.025 in three vacuum pulse mode and 0.009 in four vacuum pulse mode, respectively. The present preliminary study revealed by use of the logger that thermal differences decreased between the actual steam temperature and the saturated steam temperature corresponding to the measured pressure as the residual air amount decreased in the free chamber space. Therefore, it is suggested that the air removal effects of vacuum pulses are evaluated easily using the wireless logger in the prevacuum autoclave without sensor ports.

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