| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a thermal flowmeter having high reliability and no output drift, at a low cost. SOLUTION: The thermal folwmeter comprises a plurality of electrodes, each having a large thermal conductivity at a small duct having a small thermal conductivity and measures a flow rate of a fluid to be measured flowing through the duct. The duct is formed of a fluororesin, and the electrode are each formed of a high thermal transferring ceramics. The electrodes are welded to the duct. A metal made of an electrical resistor is formed into a circuit pattern on each of the surfaces of a heating temperature measuring sensor and a temperature- measuring sensor. Two bridge circuits for detecting the resistance value changes of the heating sensor and the measuring sensor are provided, to measure flow rate, based on the output difference of the bridge circuits.</p> |
