Flow control assembly for a valve

Abstract

A plug assembly for a valve may include a cage, an outer plug, an inner plug, and corresponding outer and inner races. The outer race may be fixed relative to the cage and the inner race may be fixed relative to the outer plug. The inner plug can be disposed within a flow chamber formed in the outer plug and secured to a valve stem of the valve. In use, within a relatively low flow range, the outer plug may remain seated on the outer race while the inner plug may move axially away from the inner race within the flow chamber to provide low flow control. Within a relatively high flow range, each of the inner and outer plugs may be lifted off from its respective race to provide higher flow control.

Description

[0001] CROSS REFERENCE TO RELATED APPLICATIONS

[0002] not applicable. Background Art

[0003] Flow control devices can be used in a variety of industrial, commercial and other settings, including regulating the flow rate or pressure of a fluid flowing from a fluid source. In certain applications, it may be useful to manage the flow rate or pressure or other characteristics of a fluid flowing from a pressure source to a downstream application or device. Summary of the invention

[0004] Some examples of the present disclosure provide a plug assembly for a valve. The valve may include a valve inlet and a valve outlet. The plug assembly may include a cage, an outer seat ring, an inner seat ring, an outer plug and an inner plug. The outer seat ring may be fixed to the cage or fixed relative to the cage. The outer plug may be in fluid communication with the valve inlet. The outer plug may be configured to move in an axial direction relative to the cage and be in sealing engagement with the outer seat ring. The inner seat ring may be fixed to the outer plug or fixed relative to the outer plug. The inner plug may be in fluid communication with the valve inlet. The inner plug may be configured to move in an axial direction relative to the outer plug and the outer seat ring. The inner plug may be sealingly engaged with the inner seat ring. In order to control the flow within a first flow range, the inner plug may be disengaged from the inner seat ring and the outer plug may be sealingly engaged with the outer seat ring. In order to control the flow within a second flow range, the inner plug may be disengaged from the inner seat ring and the outer plug may be disengaged from the outer seat ring.

[0005] In some examples, the present invention may provide a flow control assembly for a valve. The valve may include a valve body and have a valve stem. The valve body may define a valve inlet and a valve outlet. The flow control assembly may include a first valve seat, a second valve seat, a first flow control member, and a second flow control member. The first flow control member may define a flow chamber. The first flow control member may be movable in an axial direction relative to the first valve seat and may be configured to sealingly engage the first valve seat. The second valve seat may be fixed relative to the first flow control member. The second flow control member may be disposed in the flow chamber of the first flow control member and disposed on the valve stem. The second flow control member may be movable in an axial direction relative to the valve body and the first flow control member. The second flow control member may be configured to sealingly engage the second valve seat.

[0006] In some examples, the present invention may provide a method of assembling a plug assembly for a valve. The valve may include a valve stem. The method may include securing an inner plug of the plug assembly to the valve stem. The method may also include disposing the inner plug in a flow chamber of an outer plug, wherein the valve stem slidably moves through a stem hole of an outer plug of the plug assembly. The method may also include securing an inner seat ring at an opening of the flow chamber to form a sub-plug assembly, the inner plug being configured to sealingly engage the inner seat ring. The method also includes securing an outer seat ring to a first opening of a cage, the outer seat ring being configured to sealingly engage the outer plug. The method may also include inserting the sub-plug assembly into a second opening of the cage to form the plug assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a cross-sectional view of a plug assembly for a valve according to one embodiment of the disclosed technology, the plug assembly including an inner plug and an outer plug.

[0008] Figure 2 is a cross-sectional view of a plug assembly according to another embodiment of the disclosed technology, the plug assembly including an inner plug and an outer plug.

[0009] Figure 3 is a cross-sectional view of a plug assembly according to another embodiment of the disclosed technology, the plug assembly including a spring.

[0010] Figure 4 is a cross-sectional view of a plug assembly according to another embodiment of the disclosed technology, the plug assembly including an outer plug having an inclined balancing hole.

[0011] Figure 5 is a cross-sectional view of a plug assembly including an external balancing hole according to another embodiment of the disclosed technology.

[0012] Figure 6 is a cross-sectional view of a plug assembly including an external balancing hole according to another embodiment of the disclosed technology. DETAILED DESCRIPTION

[0013] The concepts disclosed in this discussion are described and illustrated with reference to exemplary arrangements. However, these concepts are not limited in their application to the details of the construction and arrangement of the components in the exemplary embodiments, and can be practiced or implemented in various other ways. The terms herein are used for descriptive purposes only and should not be considered restrictive. Words such as "comprises," "includes," and "having," and variations thereof, as used herein, are intended to encompass the items listed thereafter, their equivalents, and additional items.

[0014] While the flow control assembly disclosed herein can be embodied in many different forms, several specific embodiments are discussed herein, wherein it should be understood that the embodiments described in the present disclosure are merely to be considered as example representations of the principles described herein, and the disclosed technology is not intended to be limited to the examples shown.

[0015] As briefly discussed above, flow control devices can be used to reduce or otherwise control the flow or pressure of a fluid from a fluid source to a downstream application. Certain systems and containers require control systems or require protection to avoid overpressure. Flow control devices (such as slide valves, regulators, pressure relief valves, etc.) can be used in such systems to reduce or release excessive fluid pressure. In general, a flow control device may include an inlet, an outlet, and a flow control assembly. The flow control assembly may include a primary control member (e.g., such as a disk, a plug, or a plug assembly) and a secondary control member (such as a cage) to further restrict the flow through the flow control device.

[0016] Conventional flow control devices may include a rated maximum capacity. In certain environments or applications, it is often useful to utilize a valve with a relatively high maximum flow capacity (e.g., a mass flow rate of approximately 10,000 or 1,000,000 pounds per hour). Therefore, a valve with a relatively high rated maximum capacity will be selected. However, in the same environment or application, it may also be useful to simultaneously utilize a valve with a relatively low minimum flow capacity (e.g., approximately 1% or 10% of the rated maximum capacity). In general, large capacity valves require relatively large valve / port sizes. Therefore, traditionally, as the valve size increases, the minimum controllable capacity also increases. Therefore, a single conventional valve is often unable to meet the high and low flow requirements of a specific environment that may include widely varying flow conditions.

[0017] Embodiments of the subject matter of the present invention can address these and other shortcomings of conventional valves and flow control devices. For example, embodiments of the disclosed technology provide a flow control system that can be applied to systems that require flow control from relatively high flow rates to relatively low flow rates (an exemplary low flow rate is about 1% to 10% of the maximum rated flow rate of the flow control system). The flow control system according to embodiments of the disclosed technology can include a cage, a first plug, and a second plug. Alternatively, from another perspective, the flow control system can include a first cage, a second cage, and a plug.

[0018] The outermost first cage may surround the first plug. The first plug may form a seal with a seat ring, which may be configured as an outer seat ring relative to the fluid flow through the valve. In addition, the first plug may define a flow cavity (e.g., an inner recess). When the second plug is inserted into the flow cavity, the first plug may surround the second plug and may act as a cage for the second plug. The second plug may form a seal with a corresponding seat ring, which may be configured as an inner seat ring relative to the fluid flow through the valve.

[0019] In use, the second plug can be lifted from the inner seat and can be moved relative to the first plug (e.g., formed as an inner cage) and within the first plug, while the first plug remains in sealing engagement with the outer seat. This mode of operation can provide flow control at relatively low flow rates. In addition, in another mode of operation, the first (outer) plug can be lifted from the outer seat and can be moved relative to the outer cage and within the outer cage to provide flow control at relatively high flow rates. In some cases, the inner plug can move independently of the outer plug (e.g., at low flow rates), and when the inner plug reaches a maximum position (e.g., a maximum lift height from the inner seat), it can (directly or indirectly) cause the outer plug to lift from the corresponding outer seat to provide a higher flow rate. When the inner plug is at its maximum lift height, both the inner and outer plugs can move together to lift the outer plug from the outer seat.

[0020] In some examples, the inner plug may be fixed to the valve stem of the valve such that when the valve stem moves in the axial direction, the inner plug also moves in the axial direction. In addition, there may be a friction fit between the outer plug and the outermost cage such that the outer plug moves relative to the outermost cage only when friction has been overcome. When friction is overcome, as the valve stem moves (e.g., away from the outer seat ring), both the inner plug and the outer plug may also move together (e.g., away from the outer seat ring). The inner seat ring may be fixed to the outer plug, or at least fixed relative to the outer plug. In addition, the outer seat ring may be fixed to the outermost cage, or at least fixed relative to the outermost cage.

[0021] During valve actuation, fluid may flow from the valve inlet across the flow control system to the valve outlet. The valve action is characterized by various flow rates, including a steady flow rate or a variable flow rate. For example, the first fluid flow rate during the valve action may be a relatively low flow rate, and the second fluid flow rate during the valve action may be a relatively high flow rate, so that the first flow rate is less than the second flow rate. During the valve action with the first flow rate, the outer plug may remain in place on the outer seat ring and act as a cage-like member of the inner plug. The inner plug may be lifted from the inner seat ring accordingly and moved relative to the outer plug to provide flow control within a relatively low flow range. When the outer plug is in place on the outer seat ring and the inner plug is lifted from the inner seat ring, the fluid may flow through the radial passages in the outer plug and may also flow through the radial passages in the outermost cage-like member. In this regard, at least two sets of radial passages may provide noise attenuation and overall controlled flow for low flows.

[0022] During a valve actuation with a second, higher flow rate, the outer plug may be lifted off the outer seat ring, and the inner plug and outer plug may move together, allowing fluid to flow from the valve inlet to the valve outlet through the radial passages in the outermost cage. During the second, higher flow rate, the force felt by the outer plug by the valve stem and the inner plug may be sufficient to overcome the friction fit between the outer plug and the outermost cage, allowing the outer plug to move with the valve stem and the inner plug and relative to the outermost cage to provide flow control over a relatively high flow range.

[0023] Figure 1-6 Exemplary flow control assemblies according to various embodiments of the disclosed technology are shown. As also described below, flow control assemblies according to embodiments of the disclosed technology can include variations in form factors (e.g., variations in physical dimensions, component geometries, components of the assembly, and fluid flow paths), and can provide flow control over a wide range of flow rates, for example, between 10% and 100% of the maximum rated flow capacity of the valve, or between 1% and 100% of the maximum rated flow capacity of the valve.

[0024] Figure 1 An exemplary plug assembly 100 for a valve (not shown, but may be configured as any of a variety of known valve types) is shown. The plug assembly 100 includes a plurality of flow control members. For example, the plug assembly 100 may include a cage 102 (e.g., an outermost cage), a flow control member configured as an outer plug 104, and a flow control member configured as an inner plug 106. However, in some embodiments, the cage 102 may be considered a separate component from the plug assembly 100 (e.g., when the cage 102 is already present and the plug assembly 100 is installed as a retrofit). The plug assembly 100 may also include an outer seat ring 108 and an inner seat ring 110. The outer seat ring 108 may be configured to sealingly engage the outer plug 104, and correspondingly, the inner seat ring 110 may be configured to sealingly engage the inner plug 106.

[0025] The plug assembly 100 may also include various control elements that may be varied (e.g., in geometry and location) or omitted depending on, for example, the fluid medium, valve application, rated valve capacity, or noise attenuation requirements. These control elements may include a spring 112, a valve stem geometry, an axial balancing hole or an obliquely oriented balancing hole or an inner balancing hole 116 in the outer plug 104, and a balancing hole 118 in the inner plug 106. Generally speaking, the balancing holes help balance the pressure above, below, and between the opposing plugs. In addition, the cage 102 may include a plurality of radial channels 124, and the outer plug 104 may include a plurality of radial channels 126. It should be appreciated that the spacing, geometry (e.g., diameter), or number of the radial channels 124, 126 may also vary in embodiments of the plug assembly according to embodiments of the disclosed technology.

[0026] Continue to refer Figure 1, the cage 102 may define a cage body having an inner sidewall 132 and an outer sidewall 134. The inner sidewall 132 may face the outer plug 104, while the outer sidewall 134 may face the valve outlet ( Figure 1 106). The outer plug 104 may define an outer plug body having an inner sidewall 138 and an outer sidewall 140. The inner sidewall 138 of the outer plug 104 may face the inner plug 106, while the outer sidewall 140 of the outer plug 104 may face the inner sidewall 132 of the cage 102. In some embodiments, the outer sidewall 140 of the outer plug 104 may define a geometry that provides an intermediate flow space 144 between the outer plug 104 and the cage 102. The intermediate flow space 144 may include a gap between the cage 102 and the outer plug 104. Alternatively, as Figure 1 As shown, the intermediate flow space 144 may be larger than the minimum gap between the cage 102 and the outer plug 104 .

[0027] The outer plug 104 may also define an inner cavity configured as a flow cavity 148 within the body of the outer plug 104. The flow cavity 148 may be bounded in a radial direction (i.e., a direction perpendicular to an axis 150 of the plug assembly 100) by an inner sidewall 138 of the outer plug 104. The flow cavity 148 may be bounded in an axial direction (i.e., a direction parallel to the axis 150) by a flow cavity stop 152 at one axial end of the flow cavity 148 and by the inner race 108 at the other axial end of the flow cavity 148. In some embodiments, the flow cavity stop 152 may be configured as an inner surface and an upper surface of the outer plug 104 within the flow cavity 148.

[0028] The inner plug 106 may define an inner plug body having an outer sidewall 156 that faces the inner sidewall 138 of the outer plug 104. Each of the outer plug 104 and the inner plug 106 may be concentric with the cage 102. In use, the inner plug 106 is disposed within the flow cavity 148 of the outer plug 104. The inner plug 106 is configured to move between the inner seat ring 110 and the flow cavity stop 152. The inner plug 106 may be fixed to a valve stem 160 of the valve ( Figure 1 ). In some embodiments, the inner plug 106 can be axially fixed to the valve stem 160 via, for example, threads. Furthermore, in some embodiments, the inner plug 106 can additionally or alternatively be radially fixed to the valve stem 160 via, for example, a stem pin (see, for example, Figure 2 Rod pin 262).

[0029] The plug assembly 100 may also include one or more piston rings 164. Generally, the piston rings may facilitate relative sliding between the two bodies and may reduce or prevent fluid flow along the gap region between the bodies. Figure 1As shown, the plug assembly 100 may include piston rings 164 located within the flow chamber 148 between the inner plug 106 and the outer plug 104. These piston rings 164 can assist in the relative sliding of the inner plug 106 and the outer plug 104. In addition, the plug assembly 100 may include piston rings 164 located between the outer plug 104 and the cage 102. Likewise, the piston rings 164 can assist in the relative sliding of the outer plug 104 and the cage 102.

[0030] Continue to refer Figure 1 , the plug assembly 100 may further include a seal 166. The seal 166 may be configured as a C-seal or other gasket that provides an interference fit between the outer plug 104 and the cage 102. The interference fit provided by the seal 166 may create a friction or retention force between the outer plug 104 and the cage 102 such that the outer plug 104 cannot slide relative to the cage 102 until an external force (e.g., from the inner plug 106) overcomes the friction provided by the seal 166.

[0031] Generally, the outer plug 104 is configured to slide relative to the cage 102 during valve actuations with relatively high fluid flow rates. In contrast, the outer plug 104 is configured to remain stationary relative to the cage 102 via friction provided by the seal 166 during valve actuations with relatively low fluid flow rates. During valve actuations with relatively low fluid flow rates, the inner plug 106 may be lifted from the inner seat ring 110, and fluid may flow through the radial passages 126 of the outer plug 104 and the radial passages 124 of the cage 102. In this case, the outer plug 104 acts as a cage for the inner plug 106, and the cage 102 may act as a secondary, outermost cage that may provide further flow control and noise attenuation.

[0032] like Figure 1 As shown, the inner seat ring 110 can be fixed relative to the outer plug 104. In particular, the inner seat ring 110 can be directly fixed to the outer plug 104. In some embodiments, the inner seat ring 110 can be removably fixed (e.g., coupled) to the outer plug 104 so that the inner seat ring 110 can be removed from the plug assembly 100 or replaced during assembly or maintenance. In this regard, the inner seat ring 110 can be welded (e.g., spot welds) to the outer plug 104 at one or more weld locations 170. In other embodiments, the inner seat ring 110 can additionally or alternatively be attached to the outer seat ring 108 via one or more of pins, clips, threads, crimping, etc. Similar to the fixed relationship between the inner seat ring 110 and the outer plug 104, the outer seat ring 108 can be fixed relative to the cage 102.

[0033] As briefly described above, the plug assembly 100 is configured to accommodate a wide range of fluid flow rates. In use, when the plug assembly 100 accommodates a first (relatively low) flow rate, the inner plug 106 can be lifted from the inner seat ring 110 and moved upward in the axial direction (relative to the flow chamber 148 of the outer plug 104). Figure 1 108). In some embodiments, when the inner plug 106 is lifted from the inner seat ring 110 (e.g., by the valve stem 160), a spring (such as spring 112) can be compressed between the inner plug 106 and the flow chamber stop 152. If the pressure applied to the flow chamber stop 152 is less than the friction between the outer plug 104 and the cage 102 provided by the seal 166, the outer plug 104 remains stationary (e.g., relative to the cage 102) and in sealing engagement with the outer seat ring 108.

[0034] In a second exemplary use condition, when the plug assembly 100 accommodates a second (relatively high) flow rate, the inner plug 106 may be lifted from the inner seat 110 and moved upward in the axial direction within the flow chamber 148. The inner plug 106 may exert a force on the outer plug 104 (e.g., at the flow chamber stop 152) that, if greater than the friction force provided by the seal 166, will cause the outer plug 104 to be lifted from the outer seat 108. Figure 1 In the example shown, the spring 112 is arranged in series with the inner plug 106 to apply a lifting force to the outer plug 104 at the flow chamber stop 152. However, in other embodiments (e.g., see Figure 2 ), the inner plug 106 can directly engage the flow chamber stop portion 152 of the outer plug 104.

[0035] As briefly described above, the outer plug 104 and the inner plug 106 may optionally include a balancing hole, such as the inner balancing hole 116 or the balancing hole 118. Generally speaking, a balancing hole can be a passage extending through a body (e.g., a plug) that can allow fluid pressure to be equalized on both sides of the body. The balancing hole can generally help minimize the forces acting on the plug that the actuator must overcome. In use, the actuator can actuate the valve stem 160 to provide flow control through the plug assembly 100. The combination of one or more balancing holes can help reduce the force required to trigger the actuator stroke and open and close the valve.

[0036] like Figure 1 As shown, the inner balance hole 116 of the outer plug 104 provides a passage through the body of the outer plug 104 to fluidically connect the flow chamber 148 and the rod space 174. As shown, the inner balance hole 116 generally extends in the axial direction, however, other orientations are possible. In addition, the balance hole 118 of the inner plug 106 provides a passage through the body of the inner plug 106 to fluidly connect the flow chamber 148 and the valve inlet ( Figure 11 ). Similar to the inner balancing hole 116, the balancing hole 118 generally extends in an axial direction, however, other orientations are possible.

[0037] As described above, the plug assembly 100 can be used in a valve having an actuator. The actuator can include a controller or at least communicate with a controller to control the actuator. The actuator can actuate the valve stem 160 and provide flow control through the valve. For example, if the controller sends a signal to the actuator to allow a first flow (e.g., a relatively low flow) through the valve, the valve stem 160 can move axially upward by a first distance, which can lift the inner plug 106 from the inner seat ring 110 and provide a first flow through the plug assembly 100. Further to this example, if the controller sends a signal to the actuator to allow a second flow (e.g., a relatively high flow) through the valve, the valve stem 160 can move axially upward by a second distance. This movement can lift the inner plug 106 from the inner seat ring 110 and lift the outer plug 104 from the outer seat ring 108 via the inner plug 106 to provide a second flow through the plug assembly 100. At the second exemplary flow rate, the upward force provided by the valve stem 160 (via the inner plug 106 ) is greater than the friction force provided by the seal 166 , which allows the outer plug 104 to move relative to the cage 102 .

[0038] Figure 2-6 100. Further examples of plug assemblies according to embodiments of the disclosed technology are shown. Generally, similar reference numerals will be used to describe the following examples of similar components described in the plug assembly 100, where applicable. For example, Figure 2 The plug assembly 200 may include a cage 202, an outer plug 204, and an inner plug 206, which are similar to Figure 1 The corresponding cage 102, outer plug 104 and inner plug 106 of the plug assembly 100. It should be appreciated that, unless otherwise stated, the control, relative movement and operating principles of the following examples are the same as those described above with reference to Figure 1 Furthermore, the components, geometries, and orientations of one or more of the examples described herein may be adapted to be additionally or alternatively included in these or other plug assemblies, including for specific plug or cage geometries, balanced configurations, biasing, fixed or frictional engagements, etc.

[0039] Reference Figure 2, the plug assembly 200 includes a cage 202, an outer plug 204, and an inner plug 206. The outer plug 204 is configured to sealingly engage an outer seat ring 208, and the inner plug 206 is configured to sealingly engage an inner seat ring 210. The cage 202 can be fixed relative to the valve body 220. In addition, the inner seat ring 210 can be fixed relative to the outer plug 204. The inner seat ring 210 can be fixed to the outer plug 204 via a weld 270 or other fixing means. The inner plug 206 can be disposed within a flow cavity 248 of the outer plug 204. In addition, the inner plug 206 can be fixed to a valve stem 260 of the valve, and the valve stem 260 extends through a stem space 274 defined by the valve body 220. In some embodiments, the inner plug 206 can be threadedly fixed to the valve stem 260. In addition, in the illustrated embodiment, the plug assembly 200 can include a stem pin 262 to rotationally fix the inner plug 206 to the valve stem 260.

[0040] The plug assembly 200 may also include a piston ring 264 to facilitate sliding between the inner plug 206 and the outer plug 204 and between the outer plug 204 and the cage 202 when a certain force threshold is exceeded. A seal 266 is disposed between the outer plug 204 and the cage 202 and provides a friction fit between the outer plug 204 and the cage 202. Thus, the specific force threshold that allows the outer plug 204 to move relative to the cage 202 may be defined by the friction provided by the seal 266 (e.g., alone or in combination with the piston ring 264 and any other clearance fittings between the outer plug 204 and the cage 202). In this regard, the outer plug 204 may remain stationary relative to the cage 202 until the force felt by the outer plug 204 from the inner plug 206 overcomes the friction between the outer plug 204 and the cage 202.

[0041] In some cases, the force to overcome the threshold defined by friction can be applied by the inner plug, including indirectly via a spring as discussed above or via other intermediate elements between the inner plug and the outer plug. As another example, the inner plug can directly engage the outer plug to overcome the threshold defined by friction. For example, during use of the plug assembly 200, the inner plug 206 can engage the flow chamber stop 252 of the outer plug 204 to lift the outer plug 204 from the outer seat 208. Figure 2 In the example shown, the inner plug 206 is in an open position and lifted from the inner seat ring 210. In this orientation, fluid can flow from the valve inlet 280 through the radial passages 226 in the outer plug 204, through the radial passages 224 in the cage 202, and toward the valve outlet 282. This orientation can correspond to a relatively low flow rate through the valve.

[0042] Continue to refer Figure 2, the radial passages 226 in the illustrated embodiment may include diameters that vary in the radial direction. For example, the diameter of each radial passage 226 may have a stepped increment such that the diameter increases as the passage extends radially outward. This variation in diameter may provide additional valve noise attenuation and may facilitate manufacturing of the outer plug 204. Also, as shown in FIG. Figure 2 As shown, the radial passage can fluidly connect the flow chamber 248 and the intermediate flow space 244. In addition, Figure 2 The balancing holes of the illustrated embodiment include an inner balancing hole 216 fluidly connecting the rod space 274 and the flow cavity 248 , and a balancing hole 218 fluidly connecting the flow cavity 248 and the valve inlet 280 .

[0043] Figure 3 A plug assembly 300 according to another embodiment of the disclosed technology is shown. Similar to the plug assembly described above, the plug assembly 300 may include a cage 302, an outer plug 304, and an inner plug 306. The outer plug 304 may be configured to sealingly engage an outer seat ring 308, and the inner plug 306 may be configured to sealingly engage an inner seat ring 310. The cage 302 may be fixed relative to the valve body 320. In addition, the inner seat ring 310 may be fixed relative to the outer plug 304. The inner seat ring 310 may be fixed to the outer plug 304 via a weld 370 or other fixing means. The inner plug 306 may be disposed within a flow cavity 348 of the outer plug 304. In addition, the inner plug 306 may be fixed to a valve stem 360 of the valve, which extends through a stem space 374 defined by the valve body 320. Furthermore, in the illustrated embodiment, the plug assembly 300 may include a stem pin 362 to rotationally fix the inner plug 306 to the valve stem 360.

[0044] The plug assembly 300 may also include a piston ring 364 to facilitate sliding between the inner plug 306 and the outer plug 304 and between the outer plug 304 and the cage 302 when a certain force threshold is exceeded. A seal 366 is disposed between the outer plug 304 and the cage 302 and provides a friction fit between the outer plug 304 and the cage 302. Thus, the specific force threshold that allows the outer plug 304 to move relative to the cage 302 may be defined by the friction provided by the seal 366 (e.g., alone or in combination with the piston ring 364 and any other clearance fittings between the outer plug 304 and the cage 302). In this regard, the outer plug 304 may remain stationary relative to the cage 302 until the force felt by the outer plug 304 from the inner plug 306 overcomes the friction between the outer plug 304 and the cage 302.

[0045] exist Figure 3In the example shown, the valve is in a closed position, and each of the outer plug 304 and the inner plug 306 is seated on its respective outer seat 308 and inner seat 310. In this orientation, fluid is prevented from flowing from the valve inlet 380 through the radial passage 326 in the outer plug 304, through the radial passage 324 in the cage 302, and toward the valve outlet 382. As with the plug assembly described above, the plug assembly 300 can control a wide range of flow rates, including relatively low flow rates and relatively high flow rates. For example, during some relatively low flow rates, the inner plug 306 can be lifted from the inner seat 310, while the outer plug 304 remains seated on the outer seat 308. During relatively high flow rates, each of the outer plug 304 and the inner plug 306 can be lifted from their respective outer seat 308 and inner seat 310.

[0046] For example, during use, if the valve stem 360 moves the inner plug 306 upward, and if the upward force exerted by the inner plug 306 on the outer plug 304 exceeds the static force formed by the interference fit between the outer plug 304 and the cage 302, the outer plug 304 and the inner plug 306 may move together, causing the outer plug 304 to lift off the outer seat ring 308.

[0047] Continue to refer Figure 3 , the plug assembly 300 may include a spring 312 (e.g., a coil spring as shown, or other known types of springs for biasing axial movement). In some embodiments, the spring 312 may help the valve reach maximum flow capacity or provide more precise control by biasing the inner plug 306 away from the outer plug 304. For example, in one flow condition, as the inner plug 306 is lifted from its inner seat 308, the spring 312 may begin to compress and correspondingly begin to exert a force on the flow chamber stop 352, so that the outer plug 304 may begin to lift from the outer seat 308 before the inner plug 306 reaches its maximum lift height. Thus, with Figure 1 and Figure 2 This arrangement may provide more precise or stable flow control and apply a more gradual lifting force to the outer plug 304 compared to the example of FIG.

[0048] Figure 3 Another exemplary embodiment of a balancing hole arrangement is also shown. In particular, the inner balancing hole 316 fluidly connects the rod space 374 and the flow chamber 348, and the balancing hole 318 fluidly connects the flow chamber 348 and the valve inlet 380. In other embodiments, additional or alternative balancing holes may fluidly connect the intermediate flow space 344 to one or more of the rod space 374 or the valve inlet 380 (e.g., see Figure 1 ).

[0049] Figure 4A plug assembly 400 is shown in accordance with another embodiment of the disclosed technology. Similar to the plug assembly described above, the plug assembly 400 may include a cage 402, an outer plug 404, and an inner plug 406. The outer plug 404 may be configured to sealingly engage an outer seat ring 408, and the inner plug 406 may be configured to sealingly engage an inner seat ring 410. The outer plug 404 may include radial passages 426 and the cage 402 may include radial passages 424 to control flow. The cage 402 may be fixed relative to the valve body 420. Additionally, the inner seat ring 410 may be fixed relative to the outer plug 404. The inner seat ring 410 may be fixed to the outer plug 404 via a weld 470 or other fixing means. The inner plug 406 may be disposed within a flow cavity 448 of the outer plug 404, the flow cavity 448 including a flow cavity stop 452. Additionally, the inner plug 406 can be secured to a valve stem 460 of the valve, which extends through a stem space 474 defined by the valve body 420. Furthermore, in the illustrated embodiment, the plug assembly 400 can include a stem pin 462 to rotationally secure the inner plug 406 to the valve stem 460.

[0050] The plug assembly 400 may also include a piston ring 464 to facilitate sliding between the inner plug 406 and the outer plug 404 and between the outer plug 404 and the cage 402 when a certain force threshold is exceeded. A seal 466 is disposed between the outer plug 404 and the cage 402 and provides a friction fit between the outer plug 404 and the cage 406. Thus, the specific force threshold that allows the outer plug 404 to move relative to the cage 402 may be defined by the friction provided by the seal 466 (e.g., alone or in combination with the piston ring 464 and any other clearance fittings between the outer plug 404 and the cage 402). In this regard, the outer plug 404 may remain stationary relative to the cage 402 until the force felt by the outer plug 404 from the inner plug 406 overcomes the friction between the outer plug 404 and the cage 402.

[0051] Figure 4 Another exemplary embodiment of a balancing hole arrangement is also shown. In particular, the outer balancing hole 414 can fluidly connect the rod space 474 and the intermediate flow space 444, which is radially located between the cage 402 and the outer plug 404. In other embodiments, additional or alternative balancing holes can fluidly connect one or more of the rod space 474, the flow cavity 448, and the valve outlet 480. The outer balancing hole 414 can provide a balancing force system for the outer plug 404 during higher flow capacities when the outer plug 404 is lifted off the outer seat ring 408. This can reduce the actuator force required to close the entire valve, and can also maintain relatively precise actuation control of the inner plug 406.

[0052] Figure 5A plug assembly 500 is shown in accordance with another embodiment of the disclosed technology. Similar to the plug assembly described above, the plug assembly 500 may include a cage 502, an outer plug 504, and an inner plug 506. The outer plug 504 may be configured to sealingly engage an outer seat ring 508, and the inner plug 506 may be configured to sealingly engage an inner seat ring 510. The outer plug 504 may include radial passages 526 and the cage 502 may include radial passages 524 to control flow. The cage 502 may be fixed relative to the valve body 520. Additionally, the inner seat ring 510 may be fixed relative to the outer plug 504. The inner seat ring 510 may be fixed to the outer plug 504 via a weld 570 or other fixing means. The inner plug 506 may be disposed within a flow cavity 548 of the outer plug 504, the flow cavity 548 including a flow cavity stop 552. In addition, the inner plug 506 can be fixed to the valve stem 560 of the valve, and the valve stem 560 extends through the stem space 574 defined by the valve body 520. In addition, in the illustrated embodiment, the plug assembly 500 can include a stem pin 562 to rotationally fix the inner plug 506 to the valve stem 560.

[0053] The plug assembly 500 may also include a piston ring 564 to facilitate sliding between the inner plug 506 and the outer plug 504 and between the outer plug 504 and the cage 502 when a certain force threshold is exceeded. A seal 566 is disposed between the outer plug 504 and the cage 502 and provides a friction fit between the outer plug 504 and the cage 506. Thus, the specific force threshold that allows the outer plug 504 to move relative to the cage 502 may be defined by the friction provided by the seal 566 (e.g., alone or in combination with the piston ring 564 and any other clearance fittings between the outer plug 504 and the cage 502). In this regard, the outer plug 504 may remain stationary relative to the cage 502 until the axial force felt by the outer plug 504 from the inner plug 506 overcomes the friction between the outer plug 504 and the cage 502.

[0054] Figure 5 Another exemplary embodiment of a balancing hole arrangement is also shown. In particular, the outer balancing hole 514 can fluidly connect the rod space 574 and the valve inlet 580, and the inner balancing hole 516 can fluidly connect the rod space 574 and the flow chamber 558. In the illustrated embodiment, the inner plug 506 can be formed by an additive manufacturing process (e.g., 3D printing). The outer balancing holes 514 can be formed during the printing process due to their curved geometry in the axial direction. In contrast, outer balancing holes without curved geometry can be drilled as a secondary process after the inner plug has been formed (e.g., see Figure 6 In other embodiments, additional or alternative balancing holes may fluidly connect one or more of the intermediate flow space 544, the stem space 574, the flow chamber 548, and the valve inlet 580.

[0055] Figure 6 A plug assembly 600 according to another embodiment of the disclosed technology is shown. Similar to the plug assembly described above, the plug assembly 600 may include a cage 602, an outer plug 604, and an inner plug 606. The outer plug 604 may be configured to engage an outer seat ring 608, and the inner plug 606 may be configured to engage an inner seat ring 610. The outer plug 604 may include radial channels 626 and the cage 602 may include radial channels 624 to control flow. The cage 602 may be fixed relative to the valve body 620. In addition, the inner seat ring 610 may be fixed relative to the outer plug 606. The inner seat ring 610 may be fixed to the outer plug 606 via a weld 670 or other fixing means. The inner plug 606 may be disposed within a flow cavity 648 of the outer plug 604, the flow cavity 648 including a flow cavity stop 652. In addition, the inner plug 606 may be fixed to a valve stem 660 of the valve, which extends through a stem space 674 defined by the valve body 620. Additionally, in the illustrated embodiment, the plug assembly 600 may include a stem pin 662 to rotationally secure the inner plug 606 to the valve stem 660 .

[0056] The plug assembly 600 may also include a piston ring 664 to facilitate sliding between the inner plug 606 and the outer plug 604 and between the outer plug 604 and the cage 602 when a certain force threshold is exceeded. A seal 666 is disposed between the outer plug 604 and the cage 602 and provides a friction fit between the outer plug 602 and the cage 606. Thus, the specific force threshold that allows the outer plug 604 to move relative to the cage 602 may be defined by the friction provided by the seal 666 (e.g., alone or in combination with the piston ring 664 and any other clearance fittings between the outer plug 604 and the cage 602). In this regard, the outer plug 604 may remain stationary relative to the cage 602 until the axial force felt by the outer plug 604 from the inner plug 606 overcomes the friction between the outer plug 604 and the cage 602.

[0057] Figure 6 Another exemplary embodiment of a balancing hole arrangement is also shown. In particular, the outer balancing hole 614 can fluidly connect the rod space 674 and the valve inlet 680, while the inner balancing hole 616 can fluidly connect the rod space 674 and the flow chamber 658. In other embodiments, additional or alternative balancing holes can fluidly connect the intermediate flow space 644 (e.g., see Figure 1 ), one or more of the rod space 674, the flow chamber 648 and the valve inlet 680.

[0058] Each of the plug assemblies described above may be employed in a valve to control a variety of flow rates (eg, within a variety of low flow and high flow ranges). Figure 1-6The plug assembly configurations shown in the drawings are examples and may include other arrangements not necessarily shown in a single embodiment (e.g., replacement or combination of any number of components from two or more embodiments). In addition, each of the plug assemblies may be configured to be incorporated into a new valve, or incorporated into an existing valve as a retrofit assembly.

[0059] During assembly of a plug assembly according to an embodiment of the disclosed technology, an inner plug may be secured to a valve stem and seated within a flow cavity of an outer plug. An inner seat ring may be attached to an axial end of the outer plug opposite the valve stem to form a plug assembly. The plug assembly may then be inserted into a valve, and more specifically, into a cage fixed relative to a valve body. The outer plug may be configured to form a seal with an outer seat ring fixed relative to the cage, and the inner plug may be configured to form a seal with the inner seat ring.

[0060] Therefore, examples of the disclosed technology can provide improvements to traditional flow control components. The previous description of the disclosed examples is provided to enable those skilled in the art to make or use the disclosed technology. Various modifications to these examples will be apparent to those skilled in the art, and the general principles defined herein can be applied to other examples without departing from the spirit or scope of the disclosed technology. Therefore, the disclosed technology is not intended to be limited to the examples shown herein, but should be given the widest scope consistent with the principles and novel features disclosed herein.

[0061] Also as used herein, unless otherwise limited or defined, "or" represents a non-exclusive list of components or operations that can exist in various combinations, rather than an exclusive list of components that can only exist as alternatives to each other. For example, a list of "A, B, or C" represents the following options: A; B; C; A and B; A and C; B and C; A, B, and C. Accordingly, the term "or" as used herein is intended to represent exclusive alternatives only when preceded by an exclusive clause, such as "or," "one of," "only one of," or "exactly one of." For example, a list of "one of A, B, or C" represents the following options: A, but not B and C; B, but not A and C; C, but not A and B. A list that begins with "one or more of" (and variations thereof) and includes "or" to separate the listed elements A list of elements represents an option of one or more of any or all of the listed elements. For example, the phrases "one or more of A, B, or C" and "at least one of A, B, or C" represent the following options: one or more A; one or more B; one or more C; one or more A and one or more B; one or more B and one or more C; one or more A and one or more C; and one or more A, one or more B, and one or more C. Similarly, a list preceded by "plurality" (and variations thereof) and including "or" to separate the listed elements represents an option of multiple instances of any or all of the listed elements. For example, the phrases "plurality of A, B, or C" and "two or more A, B, or C" represent the following options: A and B; B and C; A and C; and A, B, and C.

[0062] In some embodiments, the devices or systems disclosed herein may be utilized, manufactured, installed, etc. using methods that embody aspects of the disclosed technology. Accordingly, any description herein of a particular feature, capability, or intended purpose of a device or system is generally intended to include disclosure of methods of using such a device for the intended purpose, methods of otherwise achieving such performance, methods of manufacturing components related to such a device or system (or an entire device or system), and methods of installing disclosed (or other known) components to support such purposes or performance. Similarly, unless otherwise defined or limited, any discussion herein of any method of manufacturing or method of using a particular device or system (including installing the device or system) is intended to inherently include disclosure of features and implementation capabilities used by such a device or system as an embodiment of the disclosed technology.

[0063] Also as used herein, unless otherwise defined or limited, directional terms are used to facilitate discussion with reference to a particular figure or example, or to indicate spatial relationships relative to particular other components or contexts, but are not intended to indicate absolute directions. For example, references to downward, forward, or other directions, or to top, rear, or other locations (or features), may be used to discuss various aspects of a particular example or figure, but do not necessarily require similar directions or geometries in all installations or configurations.

[0064] Also as used herein, unless otherwise limited or defined, "configured to" means that a component, system, or module is particularly adapted for the associated function. Thus, for example, ZZ configured to YY is specifically adapted to YY, as opposed to merely being generally capable of doing so.

[0065] Although the technology of the present disclosure has been described with reference to preferred examples, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the concepts discussed herein.

Claims

1. A flow control assembly for a valve, the valve having a valve inlet, the flow control assembly comprising: Cage-like parts; an outer race fixed relative to the cage; an outer plug in fluid communication with the valve inlet, the outer plug being movable in an axial direction relative to the cage to sealingly engage the outer seat ring; an inner race fixed relative to the outer plug; and an inner plug in fluid communication with the valve inlet, the inner plug being movable in an axial direction relative to the outer plug to sealingly engage the inner seat ring, In a first configuration for controlling flow within a first flow range, the inner plug is disengaged from the inner race and the outer plug is sealingly engaged with the outer race, and Wherein, in a second configuration to control flow within a second flow range, the inner plug is disengaged from the inner race and the outer plug is disengaged from the outer race.

2. The flow control assembly according to claim 1, wherein: The outer plug defines an inner cavity, and the inner plug is movable in an axial direction within the inner cavity.

3. The flow control assembly of claim 2, wherein: The inner cavity is in fluid communication with the valve inlet via one or more balancing holes extending through the inner plug.

4. The flow control assembly of claim 2, wherein: The spring is disposed in the inner cavity and between the outer plug and the inner plug relative to the axial direction.

5. The flow control assembly of claim 1, wherein: The outer plug frictionally engages the cage such that: The outer plug maintains sealing engagement with the outer seat ring within a first flow range, and In a second flow range, the inner plug applies an axial force to the outer plug to overcome the frictional engagement between the outer plug and the cage such that the outer plug disengages from the outer race.

6. The flow control assembly of claim 1, wherein: The outer plug is not secured to the valve stem of the valve and the inner plug is secured to the valve stem of the valve with respect to axial movement along the valve stem.

7. The flow control assembly of claim 1, wherein: The inner race is secured to the outer plug via one or more spot welds.

8. A flow control assembly for a valve, the valve having a valve body and a valve stem, the valve body defining a valve inlet and a valve outlet, the flow control assembly comprising: First valve seat; a first flow control member defining a flow chamber, the first flow control member being movable in an axial direction relative to the first valve seat to sealingly engage the first valve seat; a second valve seat supported by the first flow control member; and A second flow control member is disposed within the flow chamber and fixed to the valve stem, the second flow control member being movable in an axial direction relative to the valve body and the first flow control member to sealingly engage the second valve seat.

9. The flow control assembly of claim 8, further comprising: a cage circumferentially surrounding the first flow control member and the second flow control member, Wherein, the first valve seat is fixed relative to the cage-shaped member.

10. The flow control assembly of claim 9, further comprising: a seal disposed between the cage and the first flow control member to provide friction between the cage and the first flow control member, Wherein during the valve release action, the second flow control member moves axially to disengage from the second valve seat and the first flow control member remains engaged with the first valve seat until a pressure threshold on the first flow control member is met.

11. The flow control assembly of claim 9, wherein: A first set of radial passages in the first flow control member and a second set of radial passages in the cage are oriented to allow fluid flow therethrough when the first flow control member is disengaged from the first valve seat.

12. The flow control assembly of claim 8, further comprising: a spring member disposed within the flow chamber and positioned in series with the second flow control member, Wherein, the spring member biases the second flow control member toward the second valve seat.

13. The flow control assembly of claim 8, wherein: The first flow control member comprises one or more channels extending in an axial direction, and The one or more passages fluidly connect the flow chamber with a stem space of the valve, and the valve stem extends through the stem space of the valve.

14. The flow control assembly of claim 8, wherein: The second flow control member includes one or more channels extending in an axial direction, and Wherein the one or more channels fluidly connect the flow chamber with the valve inlet.

15. The flow control assembly of claim 8, wherein: The first flow control member and the second flow control member include a plurality of channels, and The plurality of channels fluidly connect a stem space of the valve with the valve inlet, and the valve stem extends through the stem space of the valve.

16. The flow control assembly of claim 8, wherein: A gap is provided between a radial sidewall of the second flow control member and a radial sidewall of the flow chamber.

17. The flow control assembly of claim 8, wherein: The first flow control member includes a plurality of radially extending passages fluidly connecting the flow chamber with the valve outlet.

18. The flow control assembly of claim 8, wherein: The second flow control member is attached to the valve stem via a threaded connection.

19. A method of assembling a flow control assembly for a valve having a valve stem, the method comprising: securing the inner plug of the plug assembly to the valve stem; The inner plug is arranged in the flow cavity of the outer plug, and the valve stem can slide through the stem hole of the outer plug of the plug assembly; securing an inner seat ring at an opening of the flow chamber to form a sub-plug assembly, the inner plug being configured to sealingly engage the inner seat ring; securing an outer race to the first opening of the cage, the outer plug being configured to sealingly engage the outer race; and The sub-plug assembly is inserted into the second opening of the cage to form the plug assembly.

20. The method according to claim 19, further comprising: The valve stem is advanced through the spring so that the spring is axially positioned between the inner and outer plugs and within the flow chamber.

Images