A valve assembly includes a valve body with a central passage, an upstream end for receiving a fluid, and a downstream end for discharging the fluid. A segment ball valve rotates between a valve open position to allow the fluid to flow through the central passage, and a valve closed position to prevent the fluid from flowing through the central passage. A check valve located within the central passage downstream from the segment ball valve is biased to prevent the fluid from traveling upstream through the central passage, and to allow the fluid to travel downstream past the check valve. A locking mechanism secures the check valve in a locked position to prevent the fluid from flowing past the check valve. A sealable cavity is located between the segment ball valve and the check valve, to contain a neutral media to achieve a double block and bleed feature.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to valves, and in particular to industrial check and block valves.

2. Description of the Related Art

In industrial operations with piping systems, such as hydrocarbon refineries, petrochemical plants, and onshore or offshore hydrocarbon production projects, a standardized piping system can have a set face to face dimension provided for each valve that restricts the valve space within the piping system to assure standardization and interchangeability with any type of valve from different manufacturers for a given pressure system. This spacing standardization is applicable to both block valves, which can open and close to turn a fluid flow on and off, and check valves, which are non-return flow valves.

In such application, the piping systems are often provided with flanges for attachment to the valves. Therefore the spacing allowed for the valve cannot be easily adjusted to allow for a larger valve assembly to be connected between the flanges of the piping system. Each required valve will need to be provided with its own standardized space or length for attaching such valve to the piping system mainly to facilitate future replacement of the valve with a valve from any manufacturer.

In some current piping systems, where a check valve and a separate closure or block valve are needed in the piping system, two standardized valve spaces would be required in the piping system to accommodate the two valves.

In another example, for a double block and bleed operation, two valves are provided that each have an sealing means for creating a barrier to fluid flow in both directions along a pipe of the piping system. Between the two valves of the double block and bleed assembly is a void space that can be vented to confirm that the dual seals are being maintained as required by, for example, the Occupational Safety and Health Administration and by other international safety organizations and practices. Therefore for traditional double block and bleed assemblies, at least two standardized valve spaces would be required in the piping system to accommodate the two valves.

SUMMARY OF THE DISCLOSURE

Embodiments of the present disclosure provide systems and methods that use only one single standard length body to accommodate both a check and block valve. As a result, one valve and one standard space can be eliminated from the piping system and a reduction in weight, space in congested systems such as, for example, in. offshore packages, and overall cost can be achieved. Reducing the number of piping system valve connections will also reduce fugitive emissions to the environment and reduce the number of separate valve connections to be verified, maintained, and repaired. Using a segment ball valve will provide sufficient internal space with the disclosed valve orientation to accommodate the second valve member, without the segment ball valve and second valve member coming in contact at any occasion. The cavity between both valve members can be a neutral zone and can be used to check the sealing integrity of both valves in the closed position. When downstream hot work is to be performed, this cavity can be injected with a neural media, such as nitrogen or other known inert gas or liquid, to provide neutral blanket against a flow of flammable fluid coming from the upstream direction. Therefore embodiments of this disclosure provide a valve assembly that has a single valve body with two separate independently sealing valves that can be used in double block and bleed operations for on-stream hydrocarbon segregation.

In an embodiment of this disclosure, a valve assembly includes a valve body with a central passage having a central axis. The valve body has an upstream end for receiving a fluid, and a downstream end for discharging the fluid. A segment ball valve is operable to rotate between a valve open position to allow the fluid to flow through the central passage and a valve closed position to prevent the fluid from flowing through the central passage. A check valve is located within the central passage downstream from the segment ball valve. The check valve is biased to prevent the fluid from traveling upstream through the central passage and to allow the fluid to travel downstream past the check valve. A locking mechanism selectively secures the check valve in a locked position to prevent the fluid from flowing past the check valve. A cavity is located between the segment ball valve and the check valve. The cavity is sealable between the segment ball valve in the valve closed position and the check valve in the locked position, to contain a neutral media.

In alternate embodiments, the valve body is a single member valve body and the segment ball valve and the check valve are located within the central passage. The valve body can include an upstream flange and a downstream flange, the flanges selectively connecting the valve assembly to a standardized flanged piping system. The valve assembly can have a port extending into the cavity for injecting the neutral media into the cavity.

In other alternate embodiments, the locking mechanism comprises two manual needle locks operable to secure a sealing surface of the check valve against a check valve seat located in the central passage. The locking mechanism can engage a downstream facing surface of the check valve piston. The check valve can be spaced axially from the segment ball valve when the ball valve is in both the valve open position and the valve closed position. The check valve can have a spring circumscribing the piston stem, urging the sealing surface in an upstream direction. When the segment ball valve is in the valve closed position, the fluid is prevented from reaching the check valve and the check valve is urged to a check valve closed position by the compressed spring. The check valve can be a piston check valve having a check valve piston with an upstream facing sealing surface and a piston stem extending from the check valve piston in a direction opposite the sealing surface.

In an alternate embodiment of this disclosure, a valve assembly includes a single member valve body having a central passage with a central axis. The valve body has an upstream end for receiving a fluid and a downstream end for discharging the fluid. The valve body also has a ball valve seat and a check valve seat. The ball valve seat is annular and located on an inner diameter of the central passage. The check valve seat is annular and located on an inner diameter of the central passage. The segment ball valve seat is closer to the upstream end and the check valve seat is closer to the downstream end. A cavity is located between the segment ball valve seat and the check valve seat. A segment ball is operable to rotate between a valve open position with the segment ball spaced from the valve seat, and a valve closed position with the segment ball in sealing engagement with the valve seat. A check valve piston is biased to prevent the fluid from traveling upstream through the central passage and to allow the fluid to travel downstream past the check valve piston. A locking mechanism selectively engages the check valve piston and secures the check valve piston in a locked position in sealing engagement with the check valve seat. The cavity has a sealed space when the segment ball is in the valve closed position and the check valve piston is in the locked position.

In other alternate embodiments, the valve body can include an upstream flange and a downstream flange, the flanges selectively connecting the valve assembly between flanges of a standardized piping system. A vent can extend into the cavity for selectively venting the fluid located in the cavity when the segment ball is in the valve closed position and the check valve piston is in the locked position. A port can extend into the cavity for injecting a neutral media into the cavity through the port. The locking mechanism can include two manual needle locks operable to engage a downstream facing surface of the check valve piston. When the segment ball is in the valve closed position, the fluid can be prevented from reaching the check valve piston and the check valve piston can be urged to a check valve closed position. The check valve piston can be spaced axially from the segment ball when the segment ball is in both the valve open position and the valve closed position.

In yet another alternate embodiment of this disclosure, a method for controlling flow of a fluid includes providing a valve assembly having a single valve body with both a segment ball valve and a check valve located within a central passage of the valve body. The segment ball valve has a valve open position to allow the fluid to flow through the central passage. The check valve is biased to prevent the fluid from traveling in an upstream direction through the central passage and to allow the fluid to travel in a downstream direction past the check valve. The segment ball valve is rotated to the valve closed position to prevent the flow of the fluid through an upstream end of the central passage. A locking mechanism of the valve assembly is moved to a locked position to secure the check valve in a locked position. A neutral media is contained in a cavity located between the segment ball valve and the check valve.

In other alternate embodiments, the neutral media can be injected into the cavity through a port that extends through the valve body. A seal integrity of the ball valve and the check valve can be confirmed by monitoring the pressure of the neutral media. The valve assembly can have an upstream flange and a downstream flange, and the valve assembly can be secured between two flanges of a standardized flanged piping system with the upstream flange and the downstream flange. A needle lock can be manually operated to secure a sealing surface of the check valve to a check valve seat located in the central passage.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be obvious to those skilled in the art that the present invention can be practiced without such specific details. Additionally, for the most part, details concerning well drilling, reservoir testing, well completion and the like have been omitted inasmuch as such details are not considered necessary to obtain a complete understanding of the present invention, and are considered to be within the skills of persons skilled in the relevant art.

Referring toFIG. 1, valve assembly10is part of piping system12. Piping system12can be a standardized piping system with a set or predetermined face to face dimension between flange faces14of piping system flanges for accommodating valves, to allow standardization and interchangeability with any type of valve from different manufacturers. Piping system12can be associated with, for example, a hydrocarbon refinery, petrochemical plant, onshore or offshore hydrocarbon production projects, or other industrial applications with large diameter flanged piping connections. Valve assembly10can be located downstream of a pump or compressor or other critical rotating equipment. Valve assembly10can have an upstream flange16aand a downstream flange16b, for connecting valve assembly10to flange faces14of piping system12. Valve assembly10can be connected to piping system12with connectors, such as for example, clamps, bolts or other threaded members.

Looking atFIGS. 1-3, valve assembly10includes valve body18that has central axis20. Valve body18is a single member body with a length along axis20that equals a standard face to face dimension for a single valve of piping system12. Valve body18has central passage22that is symmetrical about central axis20and extends from upstream end24of valve body18to downstream end26of valve body18. Fluid traveling within piping system12during normal operations is received through upstream end24of valve body18and discharged out of the downstream end26of valve body18.

Segment ball valve28and check valve30are both contained within central passage22. In the example embodiment shown, segment ball valve28has segment ball32and ball valve seat34. Segment ball32has an outer surface36that is shaped as a partial sphere. Segment ball32has an inner surface that is shaped as a partial cylinder. Ball valve seat34is an annular shaped seal member located on an inner diameter of central passage22. Ball valve seat34has a smooth surface for engaging segment ball32and can be a separate member or can be an integral part of central passage22.

Segment ball32of segment ball valve28can rotate between a valve open position (FIG. 1) and a valve closed position (FIGS. 2-3). In the valve open position, fluid can flow through central passage22past segment ball valve28. In the valve closed position fluid is prevented from flowing through the central passage22past segment ball valve28. In the valve open position, segment ball32is spaced from ball valve seat34and the inner surface of segment ball valve28aligns along central passage22to allow fluid to flow past segment ball valve28. In the valve closed position outer surface36of segment ball32is in sealing engagement with ball valve seat34to block fluid flow through central passage22.

Segment ball valve28includes a means for rotating segment ball32between the valve open position and the valve closed position. In the example embodiments ofFIGS. 1-3, stem38can be used to rotate segment ball32between the valve open position and the valve closed position. Stem38is shown extending vertically from valve body18to rotate segment ball32around a vertical stem axis perpendicular to central axis20. In alternate embodiments, stem38can extend horizontally from valve body18to rotate segment ball32around a horizontal stem axis perpendicular to central axis20.

Check valve30is a non-return flow valve and is located within central passage22downstream from segment ball valve28so that fluid in piping system12and received through upstream end24of valve body18would have to first flow past segment ball valve28before reaching check valve30. Check valve30can be a non-slam check valve. Check valve30is spaced axially apart from segment ball valve28and does not contact or interfere with segment ball valve28when segment ball valve28is in the valve open position, the valve closed position, or moving between the valve open position and the valve closed position.

In the example embodiment shown inFIGS. 1-3, check valve30is a piston check valve having check valve piston40and check valve seat42. Check valve piston40has an upstream facing sealing surface44and a downstream facing surface46opposite the upstream facing sealing surface44. Piston stem48extends from check valve piston40in a direction opposite sealing surface44. Piston stem48extends into check valve base51. Check valve base51is located downstream of check valve seat42and has a central opening for accepting piston stem48.

Check valve piston40is biased to prevent fluid from traveling upstream through central passage22past check valve30but will allow the fluid to travel downstream past check valve30. In the example embodiment, check valve30has spring52. Spring52circumscribes piston stem48and has a first end that engages downstream facing surface46of check valve piston40and a second end that engages check valve base51. Spring52urges sealing surface44in an upstream direction and into sealing engagement with check valve seat42.

Check valve seat42has an annular shaped seal surface and is located on the inner diameter of central passage22. Ball valve seat34is closer to upstream end24and check valve seat42is closer to downstream end26. Check valve seat42has a smooth seal surface for engaging sealing surface44and can be a separate member or can be an integral part of central passage22. When segment ball valve28is in the valve open position, fluid flows past segment ball valve28and can reach check valve30with sufficient force to overcome the force of spring52to move check valve piston40away from check valve seat42and into a check valve open position (FIG. 1) so that fluid can flow past check valve30and out of downstream end26of valve assembly10. In the check valve open position, downstream facing surface46of check valve piston40can contact check valve base51, limiting further downstream movement of check valve piston40. When segment ball valve28is in the valve closed position, the fluid is prevented from reaching check valve30and sealing surface44of check valve piston40is urged to a check valve closed position (FIGS. 2-3) by spring52where sealing surface44is in sealing engagement with check valve seat42.

Turning now toFIG. 4, in an alternate embodiment, check valve30can instead be a disk check valve. Check valve piston40ais a ring shaped member with upstream facing sealing surface44aand downstream facing surface46aopposite the upstream facing sealing surface44a. Piston stem48ais a ring shaped member that extends from downstream facing surface46aof check valve piston40ain a direction opposite sealing surface44a. Piston stem48aextends into check valve base51a. Check valve base51ais located downstream of check valve seats42aand42b. Check valve base51acan have an annular groove to accommodate piston stem48a. Check valve base can include a hub54which is located at an end of check valve30closest to ball valve28.

Check valve piston40ais biased to prevent fluid from traveling upstream through central passage22past check valve30but will allow the fluid to travel downstream past check valve30. In the example embodiment ofFIG. 4, check valve30has at least one spring52a. Spring52ahas a first end that engages downstream facing surface46aof check valve piston40aand a second end that engages check valve base51a. Spring52aurges sealing surface44ain an upstream direction and into sealing engagement with check valve seats42aand42b.

Check valve seat42ahas an annular shaped seal surface and is located on the inner diameter of central passage22. Check valve seat42aengages sealing surface44proximate to an outer diameter of check valve piston40a. Check valve seat42bhas an annular shaped seal surface and is located on a downstream facing portion of hub54. Check valve seat42bengages sealing surface44proximate to an inner diameter of check valve piston40a. The operation of check valve30as disk check valve as shown inFIG. 4, corresponds to the use and functionality of check valve30, as shown inFIGS. 1-3, with the numbers that include “a” and “b” suffixes inFIG. 4operating in the same manner as the numbered elements ofFIGS. 1-3, without the “a” and “b” suffixes.

Looking now atFIGS. 1-4, valve assembly10further includes a locking mechanism. The locking mechanism can secure check valve30in a locked position (FIG. 3-4) with sealing surface44in sealing engagement with check valve seat42, to prevent fluid from flowing downstream past check valve30, regardless of the fluid pressure exerted on sealing surface44of check valve30. In the example embodiment shown, the locking mechanism includes two needle locks56that can engage downstream facing surface46of check valve piston40to secure sealing surface44against check valve seat42. Needle locks56can be manually operated with handles, as shown, or can be hydraulically or otherwise mechanically operated.

Valve assembly10includes cavity58located between segment ball valve28and check valve30. Cavity58is sealable to create a sealed space that is capable of being pressurized, between segment ball valve28and check valve30when segment ball valve28is in the valve closed position and check valve30in the locked position (FIG. 3). Port60extends through a sidewall of valve body18and into cavity58and can be used to inject neutral media into cavity58. The neutral media can be, for example, air, water, or other inert liquids and gasses. Vent62can also extend through a sidewall of valve body18and into cavity58and can be used to vent fluid or other material within cavity58out of cavity58. Port60and vent62have been shown, as an example, as being located on a side of valve body18and in alternate embodiments can be located proximate or on a top or bottom of valve body18.

In an example of operation, looking atFIG. 1, in order to control the flow of fluid in piping system12, valve assembly10can be secured between flange faces14of piping system12within a standardized spacing generally sized to accommodate a single valve. Upstream flange16aand downstream flange16bof valve assembly10can be bolted or otherwise attached to flange faces14. With segment ball valve28in a valve open position and check valve30in an unlocked position, fluid flowing with sufficient force to overcome the forces of spring52can move check valve30to an open position. In this way, fluid can enter central passage22of valve body18through upstream end24of valve body18and can exit central passage22of valve body18out of the downstream end26of valve body18.

Turning toFIG. 2, by rotating stem38, segment ball32of segment ball valve28can move segment ball valve28to a valve closed position. This will stop the flow of fluid through the upstream end of central passage22of valve assembly10, upstream of segment ball valve28, by pressing outer surface36into sealing engagement with ball valve seat34. As the flow of fluid through central passage22is stopped, check valve piston40will be urged by spring52towards check valve seat42and sealing surface44will engage check valve seat42so that check valve30is in a closed position. Looking now atFIG. 3, check valve30can then be secured in a locked position by moving needle locks56of the locking mechanism so that sealing surface44of check valve30remains sealingly engaged with check valve seat42.

In this state, cavity58is sealed and can be vented and pressurized. By opening vent62, any fluids remaining in cavity58can be vented and drain out of cavity58. A neutral media can be injected through port60and into cavity58to flush cavity58of any potential flammable fluids or to pressurize cavity58. The integrity of the seal formed between segment ball32and ball valve seat34, and the seal formed between check valve piston40and check valve seat42, can be tested and confirmed by monitoring the pressure of the neutral media being injected into cavity58.

This procedure can be undertaken to achieve a double block and bleed compulsory condition whenever decision is made to perform downstream hot work. Containing neutral media in cavity58will assure no flammable fluids can pass from upstream of valve assembly10and through valve assembly10to the hot-work location. Injecting neutral media into cavity58and maintaining the pressure of the neutral media in cavity58will provide the required safe neutral zone. The neutral media will apply pressure in the inner surface of segment ball32and push outer surface36against ball valve seat34, improving the seal between segment ball32and ball valve seat34. As the same time, the neutral media will apply pressure to sealing surface44of check valve piston40, in a direction that would urge sealing surface44away from check valve seat34. However, the locking mechanism will act to retain the sealing surface44of check valve30in sealing engagement with check valve seat42. After the seal integrity of cavity58is shown be stable, and any flammable fluids leftover downstream of segment ball valve28is eliminated, downstream hot-work activity can be started.

Therefore embodiments of this disclosure provide systems and methods include valve assembly10with valve body18having an axial length of a single valve but capable of accommodating both a closure element in the form of segment ball valve28plus a non-return flow valve in the form of check valve30, to form a dual function valve. Embodiments of this disclosure provide a double closure mechanism, as required for double block and bleed operations, within a standard face to face dimension of a single valve. This saves space, weight and cost compared to instead providing two separate valves, each having an axial length of a single valve. Embodiments of this disclosure also minimize the number of piping joints, reducing fugitive emission to environment.