Measuring non-condensable gases in steam
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)
In surgery, medical devices that are used should be sterilized. To obtain surface steam sterilization conditions, not only in the sterilizer chamber itself but also in the loads to be sterilized, the amount of non-condensable gases (NCGs), for instance air, should be very low. Even rather small fractions of NCGs (below 1 %) seriously hamper steam penetration in porous materials or devices with hollow channels (e.g., endoscopes). A recently developed instrument which might detect the presence of residual NCGs in a reliable and reproducible way is the 3M{sup TM} Electronic Test System (ETS). In this paper, a physical model is presented that describes the behavior of this instrument. This model has been validated by experiments in which known fractions of NCGs were introduced in a sterilizer chamber in which an ETS was placed. Despite several approximations made in the model, a good agreement is found between the model predictions and the experimental results. The basic principle of the ETS, measuring the heat transfer by condensation on a cooled surface, permits a very sensitive detection of NCGs in harsh environments like water vapor at high temperatures and pressures. Our model may serve to develop adapted and optimized versions of this instrument for use outside the field of sterilization, e.g., in heat exchangers based on steam condensation.
- OSTI ID:
- 22251436
- Journal Information:
- Review of Scientific Instruments, Vol. 84, Issue 11; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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