| 摘要 |
PROBLEM TO BE SOLVED: To provide a cylinder for valve and the valve provided therewith which can open/close favorably over a long term and ensure an air tightness easily due to a few seal place. SOLUTION: A diaphragm valve 40 is provided with a valve rod 44 inserted in a cylinder tube 52, first/second pistons 54, 56 displaced integrally with the valve rod 44 at the displacing time of the valve rod 44, a cylindrical partition wall 58 interposed between both pistons 54, 56 and a first port 60 or second port 70 formed respectively on the rod side end of a cylinder main body 50 or head side end. The first piston 54 is inserted inside the cylindrical partition wall 58 and the second piston 56 is held on the valve rod 44 and the cylindrical partition wall 56 is engaged with the center projection 56a projected on one end surface of the second piston 56. First∼fourth rooms 28∼31 are formed inside the cylinder main body 50 and by introducing a compressed air to the first room 28 and third room 30 out of them through the first port 60, the valve rod 44 is displaced and the diaphragm valve 40 becomes open.
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