| 摘要 |
PURPOSE:To easily control a valve closing time by providing the thick shaft part of a cleaning pin on a main valve seat side and its thin shaft part on the pressure chamber side. CONSTITUTION:A cleaning pin 3 has a thick shaft part 3a having a slightly smaller diameter than the inside diameter of a small passage 2 and a thin shaft part 3b having a smaller diameter than that of the thick shaft part 3a. The thick shaft part 3a is provided on a main valve seat 4 side while the thin shaft part 3b is provided on a pressure chamber 5 side. When a main valve (a) is fully opened, the opening end part of the main flow path of the small passage 2 is positioned near the boundary part 3c between the thick shaft part 3a and the thin shaft part 3b of the cleaning pin 3. Thereby, there will be no change in the water flowing area during nearly the whole process until the main valve (a) is completely closed, making the valve close at the same rate from the fully opened condition to a closed condition. |
