Gas humidity measurement for cosmetic testing - determines resonant frequency of resonant cavities containing gas and reference medium

摘要

A method for measuring the relative humidity of a gaseous medium measures the difference in resonant frequencies in two resonant cavities (3a, 3b) placed in a reference medium and connected in parallel to the same hyperfrequency energy source (1). A gaseous medium more humid than the reference medium is introduced into one of the cavities and the difference in resonant frequencies is measured again. The difference is proportional to the relative humidity of the gaseous medium. The reference medium may be the ambient air or a vacuum, and used for analysis of e.g. cosmetics. The energy generator may be a Klystron. An electronic spectrometer connected to detectors (6a, 6b) is each cavity measures the resonant frequencies.