| 摘要 |
PURPOSE:To reduce the pressure loss due to a communication hole as far as possible by drilling the communication hole for the communication to the upstream an downstream sides onto a main valve shaft and a main valve piece and opening and closing said communication hole by a sub-valve piece. CONSTITUTION:One edge of a communication hole 23 aslantly formed towards a main valve body 4 from an installation part 5 is opened into an annular groove 19, and the other edge is opened onto the front wall of the main valve body 4. The upper edge surface of a sub-valve shaft 17 is pressed against the urging force of a spring 33 by the pressing part 28a by lifting-up an operating lever 28. Then, a sub-valve piece 16 is separated from a valve seat 18 by the above-described pressing operation, and the inflow port 2 side and the effluence port 23 side in a valve box 1 communicate through an annular goove 21, communication hole 22, annular groove 19, and a communication hole 23, and each pressure on the upstream and downstream sides of the main valve body 14 is made nearly equal. |
