| 摘要 |
A timed metering valve includes a valve body having an inlet and an outlet which are connected by a passageway surrounded by a valve seat at its upper periphery; a cylinder; a movable piston having a front face and a rear face positioned in said cylinder, the front face of said piston normally being seated upon the valve seat preventing the flow of fluid through said passageway; a bypass circuit leading from the inlet through a timing mechanism to a pressure chamber behind the rear face of the piston so that supply line pressure sensed by the rear face of the piston maintains the valve in the closed position; and relief valve means for relieving the pressure in said pressure chamber so that the supply line pressure can move the front face of the piston off its seat to open the valve. The timing mechanism comprises a disc of deformable material which is positioned in and is completely contained about its periphery by a bore in the bypass circuit, the disc has an axial passage through which fluid must pass to reach the pressure chamber and an adjustable member is provided which can be adjusted to exert an axially directed force upon the disc to deform the material of the disc into the axial opening thereby effectively reducing its effective diameter. In a preferred embodiment, especially useful for institutional shower installations, the valve is provided with a vented cover and a push button to activate the relief valve. |
