To make easily changeable the measurement range by changing a spring by providing the spring for energizing a spool in the direction for preventing the movement of the spool which is moved by pneumatic pressure.
A sleeve 3 is coaxially press-fitted on the base edge side of a housing 2, and the spool 5 with a plurality of labyrinth grooves 4 is closely fitted while sliding freely in the sleeve 3. Also, a spring pad 12 is brought into contact with the tip surface of the housing 2 for accommodating in a spring room 8, a spring 13 is fitted on a sensor rod 11, one end face and the other are brought into contact with a spring support 10 and the spring support 12, respectively, for accommodating in the spring room 8. In this case, when pneumatic pressure is applied to the pressure reception end face of the base edge side of the spool 5 with a metal seal of a labyrinth mechanism, the spool 5 is moved right, the spring 13 is compressed, and the sensor head 14 sends a pressure signal corresponding to the travel amount. In the pneumatic pressure sensor, the spring 13 is merely replaced by another spring with a different spring constant, thus easily changing the measurement range.
MIZUTANI MASASHI
DAIMARU KAZUHIKO
MAEDA KASUMI
