| 摘要 |
PURPOSE:To prevent the generation of water-hammering at the time of closing a valve by inserting a piston to which fluid resistance is applied in an auxiliary valve box mounted on the side of a main valve. CONSTITUTION:When the driving force of a pump is intercepted, a main valve body is fully opened. An auxiliary valve body 9 is also lowered by fluid force produced by a bsckward flow and spring force of a closed spring 11. Though in order to lower the auxiliary valve body 9, piston 18 coupled thereto has to be lowered at the same time, water flows out A chamber through a gap between a shaft hole 17 and an auxiliary valve shaft 8, so that the piston 18 and the auxiliary valve body 9 are slowly lowered. As the shaft diameter of the auxiliary valve shaft 8 advancing into the shaft hole 17 is gradually increased, the lowering of the auxiliary valve body 9 becomes further slower near the fully- closed condition. |
