| 摘要 |
PURPOSE:To secure constant measuring accuracy, by a method wherein the pressure receiving area of a moving member movable along the flow direction of gas to be measured in a gas flow passage is made constant regardless of the flow rate of the gas to be measured. CONSTITUTION:An air flow passage 2 is formed in a flow passage pipe 1 and a moving member 3 linearity movable along the flow of air is provided therein. The moving quantity of the moving member 3 and the increase and decrease in the area of the air flow passage the set so as to obtain predetermined functional relation. When a predetermined air flow passage Q is formed in the air flow passage 2, pressure difference is generated between the upstream and downstreams of the moving member 3 and the moving member 3 straightly advances to the downstream direction against the pressing force of a spring 11 to widen the air passage area between the outer edge part 3a of the moving member 3 and the inner peripheral wall surface of a housing 1a. A shaft 3d displaces corresponding to the movement of the moving member 3 and the brush 23 of a slider 23 of a slider 24 allow the circuit pattern of a potentiometer 18 to displace and air flow rate Q is detected as an electric signal. The moving quantity of the moving member 3 is made uniform from a low flow rate region to a high flow rate region.
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