| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a flow velocity detector enabling determination whether a flow velocity sensor is in or out of order while the flow velocity is being measured. SOLUTION: A heater sensor is constituted with a heater element 4 formed on a diaphragm member on a substrate, two temperature measuring resistor elements 5, 6 formed on the diaphragm member to change their resistance values due to heat transfer along with fluid movement, and an ambient temperature measuring resistor element 7 to change its resistance value along with its ambient temperature. To measure the flow velocity using the flow velocity sensor and a bridge circuit having the heater element 4 and the ambient temperature measuring resistor element 7, the heater element 4 is heated to a temperature higher than the ambient temperature by a specified value, and using a bridge circuit having the temperature measuring resistor elements, a voltage corresponding to the fluid flow velocity is generated. Occurrence of a trouble in the flow velocity sensor is detected by comparing the potential at the middle point of the above-described bridge with a reference value.</p> |
