| 摘要 |
<p>PROBLEM TO BE SOLVED: To do so that the flow velocity and flow rate of a fluid can be correctly measured in a low flow velocity range. SOLUTION: In a thermal flow sensor having detecting elements 3, 4 having at least one heating body 3, 4 in a passage 1 for flowing a fluid, a base board 2 for holding the detecting elements 3, 4 is disposed at a gravitationally upper side than the detecting elements 3, 4 whereby the fluid in the passage 1 is heated orderly from the vicinity of the heating bodies 3, 4 when the heating bodies 3, 4 are made heating, while the shield action of the base board 2 suppresses the natural convection from occurring, so that the flow velocity and flow rate of the fluid can be correctly measured in a low flow velocity range.</p> |
