Patent Application
20090224189
1. Field of the Invention
The present invention relates to valves and operating mechanisms for operating the valves. Some embodiments relate to a device for providing pressure containment operation of the valve.
2. Description of Related Art
Valves are used extensively in many piping systems such as, but not limited to, transmission pipelines, subsea pipelines, process piping, refineries, and power generation systems. For example, valves may be used with fittings such as the wye fittings disclosed in U.S. patent application Ser. No. 11/796,122 entitled “Reverse Flow Wye Connector” and U.S. patent application Ser. No. 11/857,972 entitled “Pipeline Systems Using A Reverse Flow Wye Connector”, which are incorporated by reference as if fully set forth herein.
A majority of valves include an actuator stem that extends from the blocking element (e.g., a ball, clapper, diverter, gate, or plunger) in the pressurized (e.g., product pressurized) internal cavity to the outside environment. The actuator stem may be sealed by a variety of methods including braid and impregnated packing, elastomer seals, polymer seals, and other types of seals in various shapes and forms. Shapes and forms include, but are not limited to, chevron, o-ring, and lip shapes. The seals contain internal product and pressure by bridging the gap between the valve body and the stem while allowing the stem to rotate relative to the body to actuate the blocking element.
Metal-type seals may be preferred for stem sealing but dynamic (e.g., rotating) metal seals are temperamental and require fine surface finishes and contaminant free environments to operate properly. Over prolonged use and/or over protracted static periods, elastomeric or polymeric valve seals may begin to leak because of deterioration due to product exposure or loss of elastomeric or polymeric properties. Leaking product may create environmental issues, health issues, and/or hazardous conditions in certain systems (e.g., pipeline systems).
In some cases, locking of the stem against inadvertent rotation is desirable to inhibit full or partial closure of the blocking element in certain situations. For example, the stem may be locked to inhibit accidental closure of the blocking element while product is flowing through the valve. Also, for safety, the stem may be locked to prevent accidental opening of the blocking element while personnel are working elsewhere on the piping system.
To solve or avoid some of the problems associated with dynamic metal seals and elastomeric or polymeric seals, a metal-sealed, locking, cap-type device is proposed. The device provides long term pressure containment to seal the stem during static periods when stem rotation is not required. The device also provides locking of the stem against inadvertent rotation.
In certain embodiments, a device includes a stem hub attached to a valve body. A rotatable stem may be located at least partially within the stem hub. The rotatable stem may rotate within the stem hub. Rotation of the rotatable stem may operate a blocking element in the valve body.
An upper stem may be coupled to a first end portion of the rotatable stem so that rotation of the upper stem rotates the rotatable stem. The upper stem may be at least somewhat moveable in a direction normal to the rotational axis of the rotatable stem and the upper stem. A metal seal may be located on the stem hub. A portion of the upper stem may press the metal seal between the upper stem and the stem hub when the upper stem is moved to a locked position. The upper stem may be inhibited from rotating or moving when in the locked position.
An operating mechanism may move the upper stem between the locked position and an unlocked position. The operating mechanism may include a clamp or ring that moves to press the upper stem against the stem hub into the locked position. The upper stem may be moved by the operating mechanism in the direction normal to the rotational axis of the rotatable stem and the upper stem. The metal seal may seal the first end portion of the rotatable stem inside the upper stem and the stem hub when the upper stem is in the locked position.
In some embodiments, one or more rotating seals are located in the stem hub and surround the rotatable stem. One or more rotating seals may be located in the valve body and surround the second end portion of the rotatable stem.
In some embodiments, the upper stem and/or the operating mechanism of a valve are actuated using a remotely operated vehicle (ROV), a hydraulic or pneumatic actuator, or human operator. The device may be used in subsea applications.
Features and advantages of the methods and apparatus of the present invention will be more fully appreciated by reference to the following detailed description of presently preferred but nonetheless illustrative embodiments in accordance with the present invention when taken in conjunction with the accompanying drawings in which:
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. The drawings may not be to scale. It should be understood that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but to the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.
In the context of this patent, the term “fitting” means a fitting or connector that may be coupled into a pipeline (e.g., a subsea pipeline, slurry pipeline, or solid transport pipeline). Fittings may include, but not be limited to, valves, diverters, wye-shaped fittings, piggable fittings, and measurement devices. The term “coupled” means either a direct connection or an indirect connection (e.g., one or more intervening connections) between one or more objects or components. The phrase “directly connected” means a direct connection between objects or components such that the objects or components are connected directly to each other so that the objects or components operate in a “point of use” manner.
In certain embodiments, fitting 100 includes body 102 and blocking element 128. Fitting 100 and body 102 may be operable in high pressure conditions due to the pressurized contained product in the pipeline or ambient pressure from deep subsea conditions. For example, fitting 100 and body 102 may be configured to meet selected ASME (American Society of Mechanical Engineers) standards, ANSI (American National Standards Institute) ratings, ASTM (American Society for Testing and Materials) standards, and/or DNV (Det Norske Veritas) standards.
As shown in
Blocking element 128 may be moved (e.g., rotated) using a drive mechanism. The drive mechanism may include drive hub 134. Drive hub 134 may be located inside body 102 and coupled to, and/or contained by, flange 110. In certain embodiments, drive hub 134 includes teeth 136 that engage with teeth 138 on blocking element 128. Teeth 136 may be formed as part of drive hub 134 or attached to drive hub 134 as a separate component (e.g., a ring gear that is attached to the drive hub by, for example, bolting, welding, or other attachment means). In some embodiments, teeth 136 and/or teeth 138 are castellations. When drive hub 134 is operated, teeth 136 engage with teeth 138 to move (e.g., rotate) blocking element 128 between the open and closed positions.
In certain embodiments, blocking element 128 and drive hub 134 are coupled to device 200. Device 200 may be used to control the operation (e.g., the rotation and orientation) of blocking element 128.
In certain embodiments, device 200 includes stem hub 208. Stem hub 208 may be attached to flange 110 or body 102 of fitting 100. For example, stem hub 208 may be welded to flange 110. In some embodiments, stem hub 208 is otherwise attached to flange 110 as is known in the art (e.g., using bolts and metal seals). Rotatable stem 206 is located at least partially within stem hub 208. An end portion of rotatable stem 206 extends from device 200. The end portion of rotatable stem 206 may be coupled to drive hub 134. Rotating seals 210 may surround rotatable stem inside stem hub 208 and inside flange 110. Rotating seals 210 inside flange 110 inhibit fluid from flowing into or out of the flange along rotatable stem 206. Rotating seals 210 inside stem hub 208 inhibit fluid from flowing into or out of device 200. In some embodiments, rotating seals 210 include two or more rotating seals made from different types of materials. Port 212 may be a pressure release port to inhibit pressure buildup along rotatable stem 206 between rotating seals 210.
Upper stem 214 is coupled to an end portion of rotatable stem 206. Upper stem 214 and rotatable stem 206 are coupled so that rotation of the upper stem rotates the rotatable stem (e.g., the coupling is a torque transmitting coupling). In certain embodiments, the end portion of rotatable stem 206 is coupled to upper stem 214 using a square coupling. For example, as shown in
Metal seal 216 is located at the coupling between stem hub 208 and upper stem 214, which may be at or near the coupling of the upper stem and rotatable stem 206. Metal seal 216 may be located in a groove or recess cavity formed in stem hub 208. Upper stem 214 may have a seal surface to accept or mate to metal seal 216. Metal seal 216 may be, for example, a Taper-Lok® wedge seal or other metal-to-metal seal such as solid metal o-rings. Pins 218 (depicted in
To place device 200 in a locked position, upper stem 214 is moved towards stem hub 208 so that metal seal 216 is pressed between the upper stem and the stem hub to create a metal to metal seal. In the locked position, the end portion of rotatable stem 206 is sealed inside upper stem 214 and stem hub 208. Using a metal to metal seal provides a substantially leak free seal that provides long term pressure containment and has a prolonged lifetime as compared to nonmetal seals (such as nonmetal o-rings or rotating seals).
Upper stem 214 is moved into the locked position by moving the upper stem towards stem hub 208 in the direction normal to the rotational axis of rotatable stem 206. Upper stem 214 is in the locked position when the upper stem engages metal seal 216 and stem hub 208. In some embodiments, frictional contact between upper stem 214, metal seal 216 and stem hub 208 inhibits rotation of upper stem and rotatable stem 206. In some embodiments, a protrusion of upper stem 214 engages a recess in stem hub 208 to inhibit rotation of upper stem and rotatable stem 206. In some embodiments, a protrusion of stem hub 208 engages a recess in upper stem to inhibit rotation of upper stem and rotatable stem 206. In the locked position, upper stem 214 is inhibited from being rotated or moved. Thus, rotatable stem 206 is inhibited from being rotated or moved and operation (opening or closing) of the fitting coupled to device 200 is inhibited.
Inadvertent rotation such as drifting of the blocking element in the fitting, which may be caused by fluid flowing through the fitting, is inhibited in the locked position. Inhibiting inadvertent rotation of upper stem 214 and rotatable stem 206 may be desirable to prevent inadvertent full or partial closure of a fitting (e.g., a valve) coupled to device 200. Inhibiting inadvertent rotation of upper stem 214 and rotatable stem 206 may be desirable to prevent inadvertent opening of a fitting (e.g., a valve) coupled to device 200.
Upper stem 214 is moved into an unlocked position by moving the upper stem away from stem hub 208 in the direction normal to the rotational axis of rotatable stem 206 and the upper stem. In the unlocked position, upper stem 214 is allowed to rotate and operate the valve coupled to the device through rotatable stem 206. In the unlocked position, metal seal 216 is not engaged between upper stem 214 and stem hub 208. Rotating seals 210 provide pressure containment when upper stem 214 is in the unlocked position.
In certain embodiments, upper stem 214 is moved between the locked and unlocked positions using an operating mechanism. The operating mechanism moves upper stem 214 in the direction normal to the rotational axis of rotatable stem 206 and the upper stem. One embodiment of the operating mechanism is depicted in
Ring clamp 220 may be shaped so that movement of the ring clamp up and down moves upper stem 214 up and down (up and down being movement in the direction normal to the rotational axis of rotatable stem 206 and the upper stem). For example, upper stem 214 may have an upset, radially-protruding flange and ring clamp 220 may have a matching shape that allows engagement with the upper stem such that movement of the ring clamp down moves the upper stem down while the ring clamp is also allowed to rotate freely around the upper stem.
Bearings 230 (depicted in
Pins 232 are alignment pins that align ring clamp 220 to upper stem 214 and inhibit the ring clamp from rotating. Ring clamp 220 has teeth on its outboard edge that engage teeth on the inboard edge of outboard ring 222. The engagement of the teeth on ring clamp 220 and outboard ring 222 are designed so that rotation of the outboard ring moves ring clamp 220 up and down. Outboard ring 222 is coupled to outboard gear 224 with fasteners 234. Fasteners 234 may be, for example, screws, bolts, or other fasteners known in the art. Outboard ring 222 is coupled to outboard gear 224 so that the outboard ring rotates in conjunction with the outboard gear.
Outboard gear 224 engages spur gear 226 with gears or teeth so that rotation of the spur gear causes rotation of the outboard gear. Rotation of spur gear 226 may be caused by rotation of actuator 228. Spur gear 226 may be, for example, a pinion gear, a cam, or other device that acts against outboard gear 224. Actuator 228 may be a male square fitting or other torque transmitting fitting known in the art.
Rotation of actuator 228 rotates spur gear 226. Rotation of spur gear 226 causes outboard gear 224 and outboard ring 222 to rotate around upper stem 214 and ring clamp 220. Because of the arrangement of the teeth on ring clamp 220 and outboard ring 222, rotation the outboard ring moves the ring clamp either up or down depending on the rotation direction (e.g., clockwise may move the ring clamp up while counterclockwise moves the ring clamp down). Movement of ring clamp 220 downwards pushes upper stem 214 towards stem hub 208 and into the locked position when metal seal 216 is pressed between the upper stem and the stem hub. Movement of ring clamp 220 upwards moves upper stem 214 upwards and away from stem hub 208 and metal seal 216 into the unlocked position.
In some embodiments, the operating mechanism is coupled to an indicator that indicates if upper stem 214 is in the locked position or the unlocked position. For example, a gear system may couple the indicator to the operating mechanism so that rotation of the actuator automatically indicates the position of the upper stem.
In some embodiments, device 200 includes an indicator that indicates if the valve coupled to the device is open or closed. For example, as shown in
In certain embodiments, the operating mechanism and/or other components of device 200 (e.g., the indictor gears) are sealed inside one or more pressure containment chambers. O-rings or other sealing elements may be used to seal the chambers containing the components of the operating mechanism and/or other components of device 200. Sealing the components of the operating mechanism and/or other components of device 200 inside pressure containment chambers may protect the components from harsh environmental conditions (e.g., subsea conditions) or other conditions that may reduce the lifetime of the components.
In certain embodiments, upper stem 214 and/or actuator 228 of the operating mechanism are operable using a remotely operated vehicle (ROV), a hydraulic or pneumatic actuator, other robotic devices, or a human operator. Upper stem 214 and/or actuator 228 may be operated using mechanically, hydraulically, pneumatically, or electrically-energized torquing tools. In some embodiments, device 200 includes other components that allow easier access for operation, movement indication, or torque reaction. For example, device 200 may include torque buckets to allow for better torque reaction to operate upper stem 214 and/or actuator 228.
Fasteners 242 may couple ring clamp 220 to stem hub 208. A portion of the ring clamp 220 may engage a flared portion of rotatable stem 206. In the unlocked position, rotatable stem 206 is able to rotate relative to ring clamp 220. Fasteners 242 may be tightened to move rotatable stem 206 to the locked position. When fasteners 242 are tightened, ring clamp 220 engages the flared portion of rotatable stem 206, and the rotatable stem is moved downwards. A portion of rotatable stem 206 presses metal seal 216 against stem hub 208 so that rotation of the rotatable stem relative to the stem hub and ring clamp 220 is inhibited. Loosening fasteners 242 allows rotatable stem to be moved upwards so that the rotatable stem is allowed to turn relative to stem hub 208
In some embodiments, the operating mechanism is coupled to commonly available hydraulic or pneumatic actuators for umbilical connected, remote operation by application of bidirectional fluid pressure. In some embodiments, the actuator is operated by a control panel mounted on an offshore platform or in the control room of a plant or refinery or at another location remote from the device.
It is to be understood the invention is not limited to particular systems described which may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. As used in this specification, the singular forms “a”, “an” and “the” include plural referents unless the content clearly indicates otherwise. Thus, for example, reference to “a seal” includes a combination of two or more seals.
Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.
