PURPOSE: To execute an exact control by an indication difference by connecting a measured pressure medium of gas or a liquid which is uniform in a visibility area and also has a comparatively large transmittivity to a transparent pipe, and enclosing a liquid-like indicating liquid into said transparent pipe.
CONSTITUTION: An indicating liquid 2 is enclosed in a glass pipe 1. Also, a measuring pressure P1 (negative pressure) and a measuring pressure P2 (positive pressure) are connected to one end of the glass pipe 1 and the other end, respectively. In this case, as for the indicating liquid 2, in case when a medium of said measuring pressure is water, an indicating liquid which is a red liquid having a constant density whose density is in a range of 1.8W3g/cm2, and has a quick change point of transmittivity in the vicinity of 600 nanometers (a peak of a man's relative luminosity factor is about 550 nanometers) is used. Also, a sensible part 3 is provided so as to be liftable so that it can track a boundary of said medium. According to this system, an exact control by an indication difference can be executed.
WATANABE NORIYUKI
SAITOU YOSHIMI
TOKYO AIRCRAFT INSTR CO
| JPS4821644U | 1973-03-12 |