| 摘要 |
<p>PROBLEM TO BE SOLVED: To exactly measure a wide range of flow by placing a plurality of pair of temperature sensors at difference distances from a micro heater by each pair on an upper and down streams of the microheater laced in air flow of a measurement fluid. SOLUTION: A microheater 12 is placed on a diaphragm 11 in air flow of a measurement fluid, and thermo-piles 13, 14 are respectively placed at an upperstream and downstream of the microheater 12 with a different distance. a cold junction group of the thermo-piles 13, 14 is laced on a wall-thickness part 11a of a sensor substrate consisting of Si, and a temperature of the measurement fluid is determined by properly contacting the cold junction group with an enclosure. A hot junction group is placed on the diaphragm 11 made of a heat insulating oxide film, and an amount of heat, which is proportional to a difference between temperatures of the measurement fluid heated by the micro heater and the jot junction group, moves to the hot junction group to warm up the hot junction group. A difference between both temperatures of the hot and cold junction groups becomes outputs of the thermo-piles 13, 14, and then flow measurement of the fluid ca be measured from a difference between the outputs.</p> |
