| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas safety device capable of detecting generation of reliquefaction when it is generated, capable of finding a stabilized flow rate value, and capable of preventing a malfunction of a safety function. SOLUTION: This gas safety device provided with an ultrasonic measuring part constituted of an ultrasonic sensor 1 and a flow passage 2, a shut-off valve 3 for shutting off gas when abnormality is generated, and a control circuit 7 for determining the propriety of normality in a gas using condition, is provided with a reliquefaction detecting means 11 for detecting a reliquefaction phenomenon with gas pressure fluctuated irregularly, a reliquefaction time measuring means 12 for averaging the fluctuated measured flow rate values when the reliquefaction is generated, and a temperature sensor 10 for measuring an ambient temperature, and the control circuit 7 is provided with a reliquefaction learning means 16 for learning a temperature change when the reliquefaction is generated, and for judging the risk of generating the reliquefaction, in advance thereto. COPYRIGHT: (C)2007,JPO&INPIT
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