| 摘要 |
<p>Provided is a thermal flow meter that has water-discharge functionality and exhibits high measurement precision. This thermal flow meter (300) is provided with an inlet-side secondary passage (4232), namely the part of a secondary passage, through which part of a gas being measured (30) that flows through a main passage (124) flows, between an inlet (350) and a measurement channel surface (430) that constitutes a flow-rate detection unit. This thermal flow meter (300) is also provided with a water-removal passage (3528) that connects to an outlet-side secondary passage (4234) between the flow-rate detection unit, i.e. the measurement channel surface (430), and an outlet (352). Said water-removal passage (3528) has a through-hole (3512) that: passes through a wall surface (4212) that forms the inlet-side secondary passage (4232); has an inlet (3542) that opens into the inlet-side secondary passage (4232); and has an outlet (3544) that opens to the opposite side (4213) of the aforementioned wall surface. Water (3552) that has gotten into the secondary passage is introduced into the through-hole (3512), guided into the outlet-side secondary passage (4234) via the water-removal passage (3528), and discharged into the main passage (124), improving measurement precision by reducing the effects of water getting into the measurement unit.</p> |
