Thermal flowmeter

Abstract

Provided is a thermal flowmeter capable of reducing a measurement error during pulsation of a fluid as compared with that in the related art. The thermal flowmeter includes: a sub-passage 307 that takes a part of a gas 30 to be measured flowing through a main passage; and a flow measurement unit 451 disposed inside the sub-passage 307. The sub-passage 307 includes: a first passage 351 provided on a measurement surface 451a side of the flow measurement unit 451; a second passage 352 provided on a back surface 451b side of the flow measurement unit 451; and an inclined passage 361 provided on an upstream side of an inlet 351a of the first passage 351 in a forward flow direction F of the gas 30 to be measured in the first passage 351. The inclined passage 361 includes a first inclined surface 371, which is inclined from the second passage 352 side toward the first passage 351 side with respect to the forward flow direction F, to be closer to the second passage 352 side than the flow measurement unit 451.

Dependencies are inferred from the claim text.