| 摘要 |
Provided are a thermal type mass flow meter and a thermal type mass flow control device, which can reduce measurement errors due to the influences of a thermal siphon phenomenon, even what position the body block might be disposed at for use, although the entire constitution can be made simple, small and inexpensive, thereby to improve the flow measuring precision. The mass flow meter comprises a correcting operation CPU, which is made operative to cancel the measurement errors due to the thermal siphon phenomenon by calculating and storing correction values from the difference between a measured value at the time when the insides of a fluid passage in the body block and a flow measuring conduit are evacuated to an atmospheric or lower pressure and a measured value at the time when the conduit is filled with an actual fluid, the kind of the actual fluid, the pressure at the actual fluid filling time, and the flow rate ratio between the fluid passage and the flow measuring conduit, and by correcting a measured output value with the correction values. |
