| 摘要 |
<p>PURPOSE:To improve measurement precision by providing the arrangement position of a heating resistor at the maximum negative-pressure position on the downstream from the minimum aperture diameter in the Venturi shape of an orifice, and rectifying the downstream flow. CONSTITUTION:A heating resistor 4 is arranged on an orifice section 7 of the Venturi shape, and a temperature-sensitive resistor 6 for detecting the air temperature is arranged on its downstream. The arrangement position of the resistor 4 is set to the maximum negative-pressure section 11 on the downstream from the minimum aperture diameter section 10 of the Venturi section of an orifice section. The change of the air flow is detected by the resistor 4 through a circuit module 5 as the change of the heating current. The air after detection is merged into a main path 2 through an orifice downstream section 9 for the rectification on the downstream, and a passage having no resistance in the flow for measurement is constituted. The precision and sensitivity for measuring the transient flow or a trace flow for a long period can be improved.</p> |
