| 摘要 |
PURPOSE:To detect difference pressure between two rooms at high sensitivity by differing the pressure receiving area of the 1st pressure receiving member from that of the 2nd one. CONSTITUTION:A communicating hole 20 is formed on a supporting member 8, and the 1st pressure receiving member 23 including a plate body 21 and a bellows 22 faces the room 6 at the side of an entrance 3 and covers the communicating hole 20. The 2nd pressure receiving member 24 has the smaller pressure receiving area S2 than that S1 of the 1st pressure receiving member 23. Thus the spring constant of the bellows 22 is made smaller and the ratio of the 1st pressure receiving area to the 2nd pressure receiving area is made larger. With this constitution, when the difference pressure between the rooms 6 and 7 arises, the plate body 25 of the 2nd pressure receiving member 24 can obtain a large displacement amount. After a shielding valve is closed, a difference pressure detector 1 can detect a drop in the pressure of the secondary room 7 at high accuracy.
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