| 摘要 |
PROBLEM TO BE SOLVED: To prevent a vacuum switch of a negative-pressure sprinkler from being damaged owing to positive pressure when pressurized water is supplied to a piping at the time of fire. SOLUTION: A center part 70d of a diaphragm 70 made of a resin film is pinched with rigid members 66, 74 from both sides. These members 70, 66, 74 are contained in a space 62 in a vessel 44 communicated with a vacuum-degree monitoring object space 36. A peripheral edge part 70c of the diaphragm is made airtightly supported to the vessel 44 to partition the space 62 into a space 62a at a side communicated with the vacuum-degree monitoring object space 36 and a space 62b at a side communicated with outer air with these members 70, 66, 74. Owing to bending of a plane area 70a exposed between the center part 70d and the peripheral edge part 70c of the diaphragm, both rigid members 66, 74 are enabled to move inside the space 62. Spring force is made to act on each rigid member 66, 74 from both sides. From movement positions of both rigid members 66, 74, a vacuum degree of the vacuum-degree monitoring object space 36 is detected. COPYRIGHT: (C)2009,JPO&INPIT
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