A pressure switch is a security component used in the intelligent gas meter. The pressure switches used by Osaka Gas are characterized by: (1) a 100% retrieval rate within ten years after installation of the gas meter, (2) an established retrieval procedure, and (3) a single model complying with identical specifications. Taking advantage of these features, the authors developed a reuse method for pressure switches. Specifically speaking, accelerated deterioration test conditions were established, a statistical procedure was developed for determining the reusability rate, and the criterion for evaluating reusability were clarified.

In this study, we investigated the effects of H₂ gas addition on electrical and optical properties of a RF capacitive atmospheric pressure non-equilibrium Ar plasma jet. It was found that the discharge behavior of the plasma jet was scarcely changed with the addition of H₂ gas. However, the discharge current decreased when trace of H₂ gas was added into the Ar plasma jet. In respect of optical emission spectrum (OES), the emission intensities of excited Ar atoms increased significantly after the addition of trace of H₂ gas. On the contrary, an expected quenching effect of H₂ gas was not observed. Based on the electrical and optical characterizations, chemical reactions in Ar-H₂ plasma jet were proposed.