| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a mass flow sensor capable of detecting a mass flow of a fluid accurately even if a mass flow meter and a mass flow controller are installed in any attitude or ambient temperature is varied. SOLUTION: A first heat sensitive resistor 21 and a second heat sensitive resistor 22 as sensor coils are wound on one vertical part 13b of a thin tube 13 which is installed vertically in reverse U-shape on a body block 1 of a mass flow meter or a mass flow controller and through which fluid flows in a state of insulating these resistors from each other, and a third heat sensitive resistor 23 is wound as a heater coil on the other vertical part 13c. Then the sensor coils 21 and 22 and the heater coil 23 are driven by drive circuits independent from each other so that the amount of heating from both coils 21 and 22 is equal to that from the coil 23.</p> |
