Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 09, 2018 - September 12, 2018
When we tried to measure the wind speed of 10 m / s or less with a Pitot tube in wind tunnels, the dynamic pressure was small and a precise fine pressure gauge was required. The Gettingen manometer could read pressure in unit of 1/10 mmAq, but a more precise micro pressure gauge was needed. So, a micro pressure gauge capable of reading pressure in unit of 1/100 mmAq was developed by using a scale and two cylindrical containers. The one container set on the scale was open to the atmosphere, the other container was a closed. About half of the containers were filled with liquid, and the two containers were connected by a pipe. The measuring pressure was connected to the closed container. When the measuring pressure changed, the liquid moved between the two containers. The changed value of the scale expressed the difference between the measuring pressure and the atmospheric pressure in units of 1/100 mmAq. Multiplying that value by the gravitational acceleration (9.8 m / s2), the pressure value in unit of Pa could be obtained. This relationship did not depend on the kind of liquid.
