| 摘要 |
PURPOSE:To improve accuracy of measurement by a device wherein pressure in an air flow rate measuring section is made to be higher or lower air suction negative pressure than the desired one exerted on a test sample and a pressure corresponding to such excess and deficiency is resupplied through a bypassing passage while measuring a flow rate thereof. CONSTITUTION:A test sample 2 is placed in an enclosed container 1 which has the desired inlet air pressure and in which a substituent for fuel of the desired preset pressure is filled. A throttle valve of the test sample 2 is held at a constant opening degree and mixture gas is sucked by a vacuum pump. The test sample 2 evaporates and sucks air and liquid substituted for fuel to form mixture gas. The mixture gas flows into a flow rate measuring section 3 and mist is separated therein. Then the remaining air is passed from a forechamber 6 to a rear chamber 7 through a sonic speed nozzle 5, so that the air flow rate is measured. Excess or deficiency of pressure in the forechamber 6 is detected by a pressure gauge 12 and then, air is sucked or supplied through a bypassing passage 8 by a flow rate control section 9 via a measuring operation mechanism 11 so as to compensate such excess or deficiency while measuring pressure by a pressure gauge 10. By so doing, the accuracy of measurement can be improved. |
