초록 ▼

A three-way normally closed relay valve is provided for selectively effecting a control action in response to pressure of a pilot fluid. A tubular valve body defines a central valve chamber for housing a valve member manually manipulatable into a relay open position for initiating service. A lower p

A three-way normally closed relay valve is provided for selectively effecting a control action in response to pressure of a pilot fluid. A tubular valve body defines a central valve chamber for housing a valve member manually manipulatable into a relay open position for initiating service. A lower piston affixed to the end of the valve member is subjected to pilot fluid pressure, and moves the valve member axially for controlling the flow of fluid between inlet, outlet, and vent ports in the valve body. An orifice in the piston intermittently establishes communication between a pilot pressure inlet port and a chamber within the valve body. The restricted orifice cooperates with a fixed seal to trap pilot pressure above and below the piston as the movable piston passes the fixed seal toward the relay closed position, and thereby prevents the valve member from moving in response to pilot pressure. A subassembly having a threaded connection for sealing engagement with the pilot inlet port is provided for economically adding to or removing from the valve body a relay opening capability in response to a remote fluid pressure and irrespective of pilot fluid pressure. The desired features of a manually responsive, three-way normally closed relay are thus obtained, although the closed relay can be opened without manual intervention by the application of remote fluid pressure.

대표청구항 ▼

A relay valve of the type including a valve body with an elongate bore within the body, a control fluid inlet port, a control fluid outlet port, a vent port, a pilot fluid inlet port, a valve stem slidable within the elongate bore, a knob affixed to the slidable valve stem for manually placing the r

A relay valve of the type including a valve body with an elongate bore within the body, a control fluid inlet port, a control fluid outlet port, a vent port, a pilot fluid inlet port, a valve stem slidable within the elongate bore, a knob affixed to the slidable valve stem for manually placing the relay valve in a relay open position, a piston affixed to the valve stem having a pilot fluid pressure surface and an opposing pressure surface, biasing means within the bore for biasing the valve stem in a relay closed position, the valve stem being selectively shiftable in response to pilot fluid pressure from (a) the relay open position establishing fluid communication between the control fluid inlet port and the control fluid outlet port and simultaneously precluding communication between the control fluid outlet port and the vent port, to (b) the relay closed position establishing fluid communication between the control fluid outlet port and the vent port and precluding fluid communication between the control fluid inlet port and the control fluid outlet port, the improvement comprising: the piston having a cylindrical interior surface of a uniform diameter between the relay open and relay closed positions of the valve stem; the valve body having a cylindrical interior body surface of a uniform diameter between the relay open and relay closed positions of the valve stem, the interior body surface defining a chamber between the piston and the vent port; a first sealing means for continued sealing engagement between the interior surface of the piston and the valve body while the valve stem moves between the relay open and relay closed positions; a second sealing means for continued sealing engagement with the interior body surface while the valve stem moves between the relay open and relay closed positions; a third sealing means for sealing engagement between the valve body and the valve stem to prevent fluid communication between the vent port and the chamber when the valve stem is in the relay closed position, and for permitting fluid communication between the vent port and the chamber when the valve stem is in the relay open position; and a fluid passageway means for controllably establishing fluid communication between the chamber and either the pilot pressure port or the vent port depending on the axial position of the fluid passageway means with respect to the first sealing means.