Pressure balanced regulating valve with flared compression disc

Claim 1

In a pressure balanced regulating valve for providing two stages of fluid flow in a fluid flow system and which comprises, a valve body provided with an inlet passage and an outlet passage; said passages being separated by a wall having a valve opening, with a valve seat around said opening for communicating said inlet passage with said outlet passage; a valve member mounted in said outlet passage and movable between a closed position in seating engagement with said valve seat and an open position spaced apart from said valve seat to allow flow of fluid from the inlet passage to the outlet passage; said valve member having a front end engageable with said valve seat and a rear end spaced apart longitudinally from said front end by an elongated structure having a closed outer surface, and said valve member further including an annular flange extended outwardly from said rear end so that the high-pressure of the fluid passing through the valve seat will dissipate itself to the low pressure in the outlet passage before reaching said annular flange; a hermetically sealed bellows in said valve body having one end fixed and the other end attached to the rear face of the flange on the rear end of said valve member so as to enclose an internal transverse face area of the valve member which is larger than the external face area on the front end of the valve member that is exposed to the inlet passage through the opening in said wall; a pilot valve; a first fluid conduit means communicating said inlet passage with the interior of said bellows and one side of said pilot valve; a second fluid conduit means communicating said outlet passage with the other side of the pilot valve and having a flow capacity larger than the flow capacity of said first fluid conduit means, whereby fluid under pressure will flow from the inlet passage into the bellows to provide a holding force on the valve member which is greater than the force exerted on the valve member by the pressurized fluid in the inlet chamber and when said pilot valve is activated a first stage of fluid flow will be initiated and fluid will pass from said inlet passage through said first and second fluid conduit means and said pilot valve into said outlet passage, said first stage of fluid flow continuing until the flow of fluid out of the second fluid conduit means into the outlet passage exceeds the flow of fluid passing from said inlet passage into said first conduit means whereby the holding force in the bellows will decrease and the force exerted on the valve member by the pressurized fluid in the inlet passage will move the valve member to the open position to indicate a second stage of full fluid flow through the regulating valve which continues until the pilot valve is deactIvated whereby the flow through the first stage is terminated and the holding force in the bellows increases and moves the valve member to the closed position; said bellows being connected to the rear face of said flange so as to provide an area for engagement by fluid which is equal to the area engageable by fluid on the front face of the flange; and, wherein the improvement comprises: means attached to the front end of the valve member and spaced apart from said valve member so as to be disposed in the inlet passage when the valve member is in both the closed and open positions, whereby when the valve is in the open position said means will be subject to the pressurized fluid in the inlet passage to provide a positive constant holding pressure on the valve member.