THERMAL TYPE FLOWMETER, AND FLOW RATE DETECTION PART PROTECTIVE DEVICE FOR THERMAL TYPE FLOWMETER

摘要

PROBLEM TO BE SOLVED: To provide a thermal type flowmeter capable of preventing a flow rate detection part from being thermally damaged in a case the flow rate detection part is exposed to a vacuum atmosphere, and to provide a flow rate detection part protective device for thermal type flowmeter capable of preventing a flow rate detection part even in a case the existing thermal type flowmeter to be arranged at a position where it is possible that the flow rate detection part is exposed to a vacuum atmosphere is exposed to a vacuum atmosphere.;SOLUTION: In a thermal type flowmeter 1, a flow rate detection part 3 having a heating resistance wire 4 being a heater, resistance wires 5A and 5B for flow speed measurement, and a resistance thermometer bulb 6 is arranged in a measurement flow passage M in a thermal type flowmeter 101, and the flow rate detection part 3 measures the flow rate of gas GS. The thermal type flowmeter 1 includes switch operation control means 80 for turning off electric conduction to the heating resistance wire 4 in order to protect the flow rate detection part 3 when exposed to a vacuum atmosphere.;COPYRIGHT: (C)2013,JPO&INPIT