Design and verification of an interlocked centrifugal exhaust system for hatch-type boiling disinfectors

To address the occupational exposure risks caused by instantaneous steam overflow when opening the top cover of hatch-type boiling disinfectors in the central sterile supply department, this study developed an interlocked centrifugal exhaust system (ICES) characterized by operational simplicity and high adaptability.

The ICES was assembled using a centrifugal fan, Hall effect switch, instant relay, time-delay relay, solid-state relay, and piping. The system achieved automatic start/stop of the fan based on the open‑or‑closed status of the top cover. A self-controlled design was adopted on one hatch-type boiling disinfector. Temperature was measured at the chamber edge (T1) and at the technician's facial position (T2). Airborne particle counts were also measured at the technician's facial position. Measurements were performed under conditions with and without the ICES enabled. Data were analyzed using the Wilcoxon signed-rank test.

After enabling the ICES, T1 and T2 decreased by 20.89% and 31.31%, respectively. The median temperature at T2 was 21.5 °C, which was close to the ambient temperature. The reduction ratios for airborne particle counts of six different sizes at the technician's facial position ranged from 53.09% to 67.83%. All differences between groups were statistically significant (all P < 0.001).

The ICES effectively reduces steam overflow upon the top-cover opening of hatch-type boiling disinfectors and lowers the risk of occupational injury. With advantages such as wide installation adaptability, imperceptible operation, and convenient maintenance, it provides a stable and reliable solution for the safety retrofitting of existing hatch-type boiling disinfectors.