| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance the output noise characteristics of a heating element type air flow rate measuring apparatus while improving the handlability by providing a protrusion in the downstream of a sub-air path. SOLUTION: A main air path 5 has substantially tubular body 3 provided with a through hole 11 penetrating from the outer wall to the inner wall. An L-shaped sub-air path 4 incorporating a heating element 7 and a temperature- sensitive element 8 is inserted into a heating element type air flow rate measuring apparatus module 9 through the through hole 11. A compositional member 2 of the sub-air path is provided, in the downstream, with a back flow prevention member 1 (protrusion) as a part of the body 3. The back flow prevention member 1 is coupled smoothly with the compositional member 2 of the sub-air path and streamlined to have semielliptical shape so that a back stream is not generated. Consequently, the air flow in the sub-air path 4 is stabilized and the output noise characteristics of a heating element type air flow rate measuring apparatus is enhanced.</p> |
