| 摘要 |
<p>PURPOSE: To achieve a flow velocity sensor which has an improved measurement sensitivity at a low-flow region and does not cause any detection error owing fo the difference in the characteristics of sensors arranged at the upstream and downstream sides of a heater. CONSTITUTION: A flow velocity sensor is provided with a heater 1 arranged in the flow of a fluid where flow velocity is to be measured, a first temperature sensor 2 arranged at the upstream side of the flow of the fluid from the heater 1, a second temperature sensor 3 arranged at the downstream side of the fluid from the heater, and an operation part 4 for calculating the flow rate of fluid based on the difference between the detection value of the first temperature sensor 2 and that of the temperature sensor 3. The first temperature sensor 2 and the second temperature sensor 3 are arranged closer to the flow of the heater 1. Also, one of the first temperature sensor 2 and the second temperature sensor 3 forms the heated contact of a pair of thermocouples and the other forms the cooled contact.</p> |
