| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To reduce impingement of dust against a sensor element, and to reduce measurement errors due to separation of flow of a fluid to be measured around the sensor element. <P>SOLUTION: In the thermal flow sensor 1A including a base part 4 provided along a flow direction of the fluid flowing in a main passage and the sensor element 2 in which a heat generating resistor 3 for detecting the flow rate of the fluid flowing in the main passage is formed on a substrate, a rectangular recessed part 5 is formed on the base part 4, the sensor element 2 is fitted into and fixed to the recessed part 5 so that a surface of its detection part is lower than an upper end edge 5a of the recessed part 5, a throttle 9 is provided at a wall part of a measurement passage facing the sensor element 2, the heat generating resistor 3 is separated to a position where it may not receive effect of turbulence of the flow of the fluid generated due to a level difference D formed between the upper end edge 5a of the recessed part 5 and the surface of the detection part of the sensor element 2 from the upstream side end edge 5a of the recessed part 5 along the flow direction. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
