| 摘要 |
PROBLEM TO BE SOLVED: To provide a diaphragm valve inhibiting fluid from flowing out of portions other than a leak flow passage when a valve is closed and easily changing minute flow rate when the valve is closed. SOLUTION: This diaphragm valve includes a valve box 11 forming a flow-in passage 11a and a flow-out passage 11b and having a valve chamber 11c formed in a middle of the passage, a valve seat collar 12 as a thick wall cylindrical body valve seat reinforcement member surrounding a flow-in passage outlet edge part opening at a bottom wall of the valve chamber 11c, a resin valve seat 13 fitted and retained in such a manner that a part projects from the valve seat collar 12, a diaphragm 15 closing/opening by approaching to/separating from a projection part of the valve seat 13, and a seat ring 14 as a press member pressing at least the valve seat collar 12 toward a bottom wall of the valve chamber 11c, and has the leak flow passage 20 providing communication between the flow-in passage 11a and the flow-out passage 11b, and an annular rib 12a projecting from a contact surface with the bottom wall of the valve chamber 11c, both being formed on the valve seat collar 12. COPYRIGHT: (C)2010,JPO&INPIT
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