Pressure balanced valve

Claim 2

A valve construction comprising a body having inlet and outlet ports intersecting an intermediate chamber, one portion of which is defined by a bore in said body, a cover for said bore, means providing a valve seat between said chamber and said outlet port, a main valve closure member mounted for movement between open and closed positions in said chamber and having a seating surface adapted to sealingly engage said valve seat when said main valve is closed, main valve actuator means including a tubular shaft to one end of which said main valve closure member is removably connected, piston means connected to the other end of said shaft and slidable within said bore, said main valve closure member having an opening aligned with said tubular shaft and an auxiliary valve seat surrounding said opening, a valve stem extending through said tubular shaft, said bore, and said cover, said stem spaced from said tubular shaft to define an annular passageway therebetween, an auxiliary valve member removably connected to one end of said stem and having a seating surface engaging said auxiliary seat when said auxiliary valve member is in a closed position, lost motion means operatively connecting said stem with said tubular shaft, fluid passage means in said shaft establishing fluid communication between said intermediate chamber and said annular passageway to conduct upstream fluid through said passageway to said bore when said main and auxiliary valves are closed, means connecting said annular passageway with said main valve opening when said auxiliary valve is fully opened and means disconnecting said passageway and said shaft fluid passage means when said auxiliary valve is fully opened, whereby when the main and auxiliary valve members are closed the fluid pressure in said bore acts upon said piston means to seat said main valve member and when said auxiliary valve member is opened said fluid pressure in said bore bleeds through said annular passageway and said main valve opening to balance the pressure acting on said piston means with that downstream of said main valve member and thereby permit said main valve member to be readily opened.

Claim 3

A valve construction as in claim 1, said main valve member being disc-shaped and being spaced from said piston means within said intermediate chamber by said tubular shaft, said piston means including peripheral sealing means engaging the wall of said bore and sealing said bore from said intermediate chamber when said main valve is closed.

Claim 4

A valve construction as in claim 1, said auXiliary valve member having an actuating surface spaced from a coacting mating surface on said tubular shaft when said auxiliary valve is closed, said surfaces providing said lost motion connecting means between said stem and said tubular shaft, whereby upon movement of said stem said pressure bleed is established before said auxiliary valve actuating surface engages said shaft mating surface to open said main valve member.

Claim 5

A valve construction as in claim 3, said shaft fluid passage means terminating at one end at said shaft mating surface, said auxiliary member actuating surface blocking said shaft fluid passage means upon engagement with said shaft mating surface to disconnect said annular passageway from said intermediate chamber, said auxiliary valve member including aperture means providing said means connecting said annular passageway with said main valve opening when said auxiliary valve is fully opened.

Claim 6

A valve construction as in claim 1, said lost motion connecting means including a hollow boss member connected to said one end of said stem and terminating in an end flange and a collar on said stem positioned within said boss member and spaced a distance from said end flange when said auxiliary valve member is closed, whereby after said stem is moved said spaced distance to engage said collar with said end flange, said main valve member will be opened.

Claim 7

A valve construction as in claim 5, said shaft fluid passage means extending through said boss member and communicating the interior of said boss member with said intermediate chamber, said boss member comprising fluid passageway means connecting said shaft passage means with said annular passageway when said auxiliary valve member is closed and said annular passageway with said main valve opening when said auxiliary valve is fully opened with said collar engaging said end flange and blocking said shaft passage means.

Claim 8

A valve construction as in claim 1, said main valve closure member construction comprising a continuous peripheral groove in the region adjacent said main valve seating surface to impart localized flexibility to said valve member, thereby enabling it to conform to distortion in said valve seat and ensuring the formation of a droptight seal.

Claim 9

A valve assembly for a pipeline conducting fluid under pressure comprising a body having a through passage provided with an annular seat, a main valve member comprising a disc adapted to engage said seat in closed position, means providing an opening through said disc, an auxiliary valve member adapted to close said opening in the closed condition of said valve assembly, fluid pressure responsive means connected to said disc and having an actuating chamber, a valve stem connected to said auxiliary valve member, an actuator for said valve stem, passage means operable when both the main and auxiliary valve members are in closed position for applying upstream line pressure to the actuating chamber for said pressure responsive means to urge said disc onto its seat in said body, said passage means comprising an auxiliary chamber surrounding said auxiliary valve means, an inlet conduit connecting said auxiliary chamber to upstream line pressure, and an annular passage section defined by a tubular shaft of small diameter compared to said disc disposed in the connection between the disc and pressure responsive means closely surrounding the stem for connecting the auxiliary chamber in fluid communication with said actuating chamber, means providing a lost motion coupling between said auxiliary valve member and said main valve member whereby initial opening movement of the valve stem by said actuator displaces the auxiliary valve member with respect to said main valve member to sequentially uncover said opening and solidly couple said valve members together, means movable with said auxiliary valve member adapted to close said conduit to block upstream fluid pressure from said passage means, said auxiliary chamber being connected through said openinG to the line downstream of said valve assembly when said auxiliary valve is displaced to apply downstream line pressure to said fluid pressure responsive means so that when further movement of said valve stem by said actuator displaces said main valve member from its seat pressure balance will have been substantially reestablished on opposite sides of said main valve member so as not to materially interfere with opening movement of said main valve member.

Claim 10

A valve assembly for a pipeline conducting fluid under pressure comprising a body having a through passage provided with an annular seat, a main valve member comprising a disc adapted to engage said seat in closed position, means providing an opening through said disc, an auxiliary valve member adapted to close said opening in the closed condition of said valve assembly, fluid pressure responsive means connected to said disc and having an actuating chamber, a valve stem connected to said auxiliary valve member, an actuator for said valve stem, passage means operable when both the main and auxiliary valve members are in closed position for applying upstream line pressure to the actuating chamber for said pressure responsive means to urge said disc onto its seat in said body, said passage means comprising an auxiliary chamber surrounding said auxiliary valve means, an inlet conduit connecting said auxiliary chamber to upstream line pressure, and an annular passage section defined by a tubular shaft of small diameter compared to said disc disposed in the connection between the disc and pressure responsive means closely surrounding the stem for connecting the auxiliary chamber in fluid communication with said actuating chamber, means providing a lost motion coupling between said auxiliary valve member and said main valve member whereby initial opening movement of the valve stem by said actuator displaces the auxiliary valve member with respect to said main valve member to sequentially uncover said opening and solidly couple said valve members together, means movable with said auxiliary valve member adapted to close said conduit to block upstream fluid pressure from said passage means, said auxiliary chamber being connected through said openinG to the line downstream of said valve assembly when said auxiliary valve is displaced to apply downstream line pressure to said fluid pressure responsive means so that when further movement of said valve stem by said actuator displaces said main valve member from its seat pressure balance will have been substantially reestablished on opposite sides of said main valve member so as not to materially interfere with opening movement of said main valve member.

Claim 11

A valve assembly for a pipeline conducting fluid under pressure comprising a body having a through passage provided with an annular seat, a main valve member in the form of a disc adapted to engage said seat in closed position, means providing a central opening through said disc, an auxiliary valve member adapted to seat upon and close said opening in the closed condition of said valve assembly, a valve stem connected to said auxiliary valve member, a pressure responsive actuator for said valve stem, a piston disposed in a piston chamber in said body, means solidly connecting said piston to said disc comprising a tubular shaft rigid at opposite ends with said piston and said disc, said tubular shaft being of relatively small diameter as compared to said disc and surrounding said stem so as define between the shaft and stem an annular passageway leading to said piston chamber, means for applying upstream line pressure to said piston chamber to urge said disc onto its seat in said body, means providing a lost motion coupling between said auxiliary valve member and said disc whereby initial opening movement of the valve stem by said actuator displaces the auxiliary valve member with respect to said disc to uncover said opening, and means defining a passageway section through said auxiliary valve member that connects said annular passage means to the line downstream of said valve assembly through said opening to connect said piston chamber to downstream line pressure upon said initial opening movement of said valve stem so that pressure balance is substantially established on opposite sides of said main valve member so as not to materially interfere with opening of said main valve member, said lost motion coupling means being effective on further movement of said auxiliary valve member to solidly couple the disc and auxiliary valve member.

Claim 12

A valve assembly for a pipeline conducting fluid under pressure comprising a body having a through passage provided with an annular seat, a main valve member in the form of a disc adapted to engage said seat in closed position, means providing a central opening through said disc, an auxiliary valve member adapted to seat upon and close said opening in the closed condition of said valve assembly, a valve stem connected to said auxiliary valve member, a pressure responsive actuator for said valve stem, a piston disposed in a piston chamber in said body, means solidly connecting said piston to said disc comprising a tubular shaft rigid at opposite ends with said piston and said disc, said tubular shaft being of relatively small diameter as compared to said disc and surrounding said stem so as define between the shaft and stem an annular passageway leading to said piston chamber, means for applying upstream line pressure to said piston chamber to urge said disc onto its seat in said body, means providing a lost motion coupling between said auxiliary valve member and said disc whereby initial opening movement of the valve stem by said actuator displaces the auxiliary valve member with respect to said disc to uncover said opening, and means defining a passageway section through said auxiliary valve member that connects said annular passage means to the line downstream of said valve assembly through said opening to connect said piston chamber to downstream line pressure upon said initial opening movement of said valve stem so that pressure balance is substantially established on opposite sides of said main valve member so as not to materially interfere with opening of said main valve member, said lost motion coupling means being effective on further movement of said auxiliary valve member to solidly couple the disc and auxiliary valve member.