Balanced pressure trim assembly for valves

Abstract

The invention relates to a valve trim assembly for use in a valve, such as an emergency shut-off valve. The valve trim assembly includes a valve plug, a piston, and a valve stem coupled to the valve plug and the piston. The valve plug includes a plug body, a plug plate disposed between a first end and a second end of the plug body, a balancing port formed through the plug plate and fluidly connecting the first end and the second end, a boss disposed proximate the first end, and a plug slot formed between the plug plate and the boss. The piston includes a piston body, a boss disposed proximate a first end of the piston body, and a piston slot formed in the piston body, the piston slot partially defined by the boss. The valve rod is provided with a first end and a second end, the first end is firmly arranged in the piston groove, and the second end is opposite to the first end and is firmly arranged in the piston groove.

Description

Technical Field

[0001] The present disclosure relates generally to valves and, more particularly, to a balanced pressure trim assembly for a valve, such as a slam-shut valve. Background Art

[0002] Gas distribution systems, such as those used to distribute natural gas, typically transport gas from producers to consumers along a series of pipelines and through a series of valves. Each gas distribution system may include one or more regulating valves that control the gas pressure within the distribution system. Normally, gas is transported through the system at high pressure. However, before final distribution to consumers, the gas pressure must be reduced. This pressure reduction is typically accomplished at pressure reducing stations within the local network.

[0003] These pressure reducing stations generally include one or more pressure regulating valves (which may be referred to herein as "regulators" or "primary regulators") and some kind of safety device that cuts off the gas flow when the pressure regulating valve fails. Most commonly, an emergency shut-off safety valve is used for this purpose. For example, U.S. Patent No. 4,134,421 discloses an emergency shut-off safety valve that provides overpressure protection in a pipeline. Another example of an emergency shut-off safety valve is disclosed in U.S. Patent No. 8,225,812. The emergency shut-off safety valve is usually arranged upstream of the pressure regulating valve so that the emergency shut-off valve can prevent gas from reaching the pressure regulating valve when the pressure regulating valve fails. The emergency shut-off safety valve monitors the gas pressure downstream of the pressure regulating valve. If the downstream pressure deviates from a predetermined range (i.e., above the upper pressure limit or below the lower pressure limit), the emergency shut-off safety valve closes, thereby cutting off the gas flow to the pressure regulating valve and preventing the gas pressure downstream of the pressure reducing station from getting out of control due to a failure of the pressure regulating valve. Summary of the Invention

[0004] According to a first exemplary aspect of the present invention, a valve trim assembly for use in a valve is provided. The valve trim assembly includes a valve plug, a piston, and a valve stem coupled to the valve plug and the piston. The valve plug includes a plug body having a first end and a second end opposite the first end, a plug plate disposed in the plug body between the first end and the second end, a balancing port formed through the plug plate and fluidically connecting the first end and the second end, a boss disposed proximate to the first end, and a plug groove formed between the plug plate and the boss. The piston includes a piston body having a first end and a second end opposite the first end, a boss disposed proximate to the first end, and a piston groove formed in the piston body, the piston groove being partially defined by the boss. The valve stem has a first end and a second end opposite the first end, the first end being securely disposed in the plug groove, and the second end being securely disposed in the piston groove.

[0005] According to a second exemplary aspect of the present invention, a valve is provided. The valve includes: a valve body including an inlet, an outlet, and a fluid passage connecting the inlet and the outlet; and a valve trim assembly. The valve trim assembly includes: a valve seat disposed in the fluid passage of the valve body; a valve plug movable relative to the valve seat to control the flow of fluid through the fluid passage, the valve plug including: a plug body having a first end and a second end opposite to the first end, a plug plate disposed in the plug body between the first end and the second end, a balancing port formed through the plug plate and fluidically connecting the first end and the second end, a boss disposed proximate to the first end, and a plug groove formed between the plug plate and the boss; a piston including a piston body having a first end and a second end opposite to the first end, a boss disposed proximate to the first end, and a piston groove formed in the piston body, the piston groove being partially defined by the boss; and a valve stem coupled to the valve plug and the piston, the valve stem having a first end and a second end opposite to the first end, the first end being securely disposed in the plug groove, and the second end being securely disposed in the piston groove. The valve further includes a cover plate assembly coupled to the valve body, the cover plate assembly including a piston chamber, wherein the piston is movably disposed in the piston chamber.

[0006] According to a third exemplary aspect of the present invention, a method for forming a valve is provided. The method includes obtaining a valve body comprising an inlet, an outlet, and a fluid passage connecting the inlet to the outlet. The method also includes positioning a valve seat in the fluid passage of the valve body; and positioning a valve plug in a chamber of the valve body, the valve plug including: a plug body having a first end and a second end opposite the first end, a plug plate disposed in the plug body between the first and second ends, a balancing port formed through the plug plate and fluidically connecting the first and second ends, a boss disposed proximate the first end, and a plug groove formed between the plug plate and the boss. The method also includes obtaining a piston, the piston including a piston body having a first end and a second end opposite the first end, a boss disposed proximate the first end, and a piston groove formed in the piston body, the piston groove being partially defined by the boss. The method also includes securely seating the first end of the valve stem in the plug groove by axially positioning the first end of the valve stem in the plug groove and radially positioning the valve plug such that the boss of the valve plug engages the first end of the valve stem. The method also includes securely positioning the second end of the valve stem in the piston groove by axially positioning the second end of the valve stem in the piston groove and radially positioning the piston so that the boss of the piston engages with a portion of the valve stem proximate the second end of the valve stem.

[0007] According to the first aspect, the second aspect and / or the third aspect above, the valve plug assembly and / or the method may further include any one or more of the following preferred forms.

[0008] According to a preferred form, the valve stem includes an annular groove formed adjacent to the first end of the valve stem, and wherein the boss of the valve plug is arranged to be disposed in the annular groove to firmly retain the first end of the valve stem in the plug groove.

[0009] According to another preferred form, a valve stem connector is coupled to the second end of the valve stem, wherein the valve stem connector is arranged to engage the boss of the piston to securely retain the second end of the valve stem in the piston groove.

[0010] According to another preferred form, the valve stem connector is threadedly connected to the second end of the valve stem.

[0011] According to another preferred form, the valve stem includes a second annular groove formed adjacent to the second end of the valve stem, and wherein the valve stem connector is disposed in the second annular groove.

[0012] According to another preferred form, a guide plate is coupled to the valve stem between the first end and the second end of the valve stem, the guide plate being configured to prevent radial movement of the valve stem.

[0013] According to another preferred form, the diameter of the balancing port is smaller than the diameter of the plug groove.

[0014] According to another preferred form, the valve trim assembly includes: a valve seat adapted to be disposed in a valve body of the valve; a plug cap surrounding the valve plug; and one or more sealing elements carried by the valve plug, the one or more sealing elements being disposed between an outer surface of the valve plug and the plug cap. The valve plug is movable relative to the valve seat to control the flow of fluid through the valve trim assembly.

[0015] According to another preferred form, the plug groove and the piston groove are both radial grooves oriented in the radial direction.

[0016] According to another preferred form, one end of the spring abuts against the piston, and the other end abuts against the cover plate assembly.

[0017] According to another preferred form, a guide plate is constrained between the cover plate assembly and the valve plug, wherein the guide plate is coupled to the valve stem between the first end and the second end of the valve stem to prevent radial movement of the valve stem.

[0018] According to another preferred form, the valve stem includes an annular groove formed adjacent to the first end of the valve stem, and the boss of the valve plug is arranged to be disposed in the annular groove to firmly hold the first end of the valve stem in the plug groove.

[0019] According to another preferred form, a valve stem connector is coupled to the second end of the valve stem, wherein the valve stem connector is arranged to engage the boss of the piston to securely retain the second end of the valve stem in the piston groove.

[0020] According to another preferred form, the valve stem connector is threadedly connected to the second end of the valve stem.

[0021] According to another preferred form, the valve stem includes a second annular groove formed adjacent to the second end of the valve stem, and wherein the valve stem connector is disposed in the second annular groove.

[0022] According to another preferred form, the diameter of the balancing port is smaller than the diameter of the plug groove.

[0023] According to another preferred form, a plug cap surrounds the valve plug; and the valve plug carries one or more sealing elements, the one or more sealing elements being arranged between an outer surface of the valve plug and the plug cap.

[0024] According to another preferred form, the plug groove and the piston groove are both radial grooves oriented in the radial direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a cross-sectional view of a known emergency shut-off valve, showing the valve plug of the known valve in an open position;

[0026] Figure 2 and Figure 1 Similar, but showing the pressure distribution when the valve plug is in the closed position;

[0027] 3 is a perspective view of an example slam shut valve employing an example pressure trim assembly constructed in accordance with the teachings of the present disclosure;

[0028] Figure 4 3 is a cross-sectional view showing the valve plug of the pressure trim assembly in an open position;

[0029] Figure 5A This is an exploded view of the valve plug;

[0030] Figure 5B is a perspective view of the valve plug;

[0031] Figure 5C is a cross-sectional view of the valve plug;

[0032] Figure 5D and Figure 5C Similar, but with the valve plug sealing element removed;

[0033] Figure 5E For the Figure 5D A cross-sectional view taken along line 5-5;

[0034] Figure 5F for Figure 5E perspective drawing;

[0035] Figure 6A An exploded view of the piston and actuator rod of the pressure trim assembly;

[0036] Figure 6B is a perspective view of the piston;

[0037] Figure 6C is a cross-sectional view of the piston and the actuator rod when coupled to the piston;

[0038] Figure 6D is a cross-sectional view of the piston;

[0039] Figure 6E For the Figure 6D a cross-section taken along the midline 6-6;

[0040] Figure 6F for Figure 6E perspective drawing;

[0041] Figure 7 An exploded view of how the valve plug, piston, and stem of the pressure trim assembly are connected together;

[0042] Figure 8A is a perspective view of the actuator rod;

[0043] Figure 8B An exploded view of the guide plate of the pressure trim assembly;

[0044] Figure 8C is a cross-sectional view of the guide plate;

[0045] Figure 9A An exploded view of the plug cap of the pressure trim assembly;

[0046] Figure 9B is a cross-sectional view of the plug cap;

[0047] Figure 10 is a cross-sectional view of a valve plug disposed in a plug cap;

[0048] Figure 11 and Figure 4 similar, but showing the valve plug in the closed position;

[0049] Figure 12Figure 3 shows an example of a ball valve and a pilot valve connected to the Figure 11 valve;

[0050] Figure 13 is a cross-sectional view of another example of a valve constructed in accordance with the teachings of the present disclosure and including a pressure trim assembly; and

[0051] Figure 14 is a cross-sectional view of another example of a valve constructed in accordance with the teachings of the present disclosure, which employs another example of a pressure trim assembly. DETAILED DESCRIPTION

[0052] Figure 1 and Figure 2 A known example of a slam-shut valve 100 is shown. As shown, the slam-shut valve 100 includes a valve body 104, a bonnet 105 coupled to the valve body 104, a spring cartridge 106 coupled to the bonnet 105, and a trim assembly 108 disposed within the valve body 104, the bonnet 105, and the spring cartridge 106. The valve body 104 defines an inlet 112 and an outlet 116 connected by a fluid passage 120. The trim assembly 108 includes a valve seat 124, a valve stem 128, a valve plug 132, a piston 136, and a spring 140. The valve seat 124 is disposed in the fluid passage 120. The valve stem 128 has a first end threadedly coupled to the valve plug 132 and a second end threadedly coupled to the piston 136. The valve plug 132 movably interacts with the valve seat 124 to control fluid flow through the fluid passage 120. The piston 136 is movably disposed within the bonnet 105. A spring 140 is disposed in the spring case 106 and is configured to bias the top of the piston 136 in a direction toward the valve seat 124 .

[0053] The piston 136 is movable in response to downstream pressure, which is fluidically coupled to the valve cover 105 (more specifically, the piston 136) via a port 142 formed in the valve cover 105. When the downstream pressure deviates from a predetermined range (e.g., is above an upper pressure limit), the downstream pressure exerts a force on the bottom of the piston 136 that exceeds the biasing force exerted by the spring 140, and the piston 136 moves upward (at least in this direction), causing the valve stem 128 to move upward (at least in this direction). The upward movement of the valve stem 128 causes the valve plug 132 to move toward the valve seat 124 and contact the valve seat 124, thereby shutting off the flow of fluid through the fluid passage 120, as shown in FIG. Figure 2 As shown, the emergency shut-off valve 100 is closed. Conversely, when the downstream pressure is within a predetermined range, the force exerted by the downstream pressure on the bottom of the piston 136 is less than the biasing force exerted by the spring 140, and the piston 136 moves downward (at least in this direction), causing the valve stem 128 to move downward (at least in this direction). The downward movement of the valve stem 128 causes the valve plug 132 to break away from contact and move away from the valve seat 124, thereby allowing fluid to flow through the fluid passage 120, as shown. Figure 1As shown, the emergency shut-off valve 100 is opened (or kept open).

[0054] However, the known slam shut valve 100 may encounter several problems. First, because the valve plug 132 is unbalanced, when the valve plug 132 rests on the valve seat 124, as shown in FIG. Figure 2 As shown, a first side of the valve plug 132 is subjected to a first force generated by the pressure at the outlet 116, while a second side of the valve plug 132 is subjected to a second force generated by the pressure at the inlet 112, which is different from the first force. In other words, the first and second sides of the valve plug 132 are subjected to different forces, and the exact value of this pressure differential depends on the operating environment of the known slam-shut valve 100 (i.e., the pressure at the inlet 112 and the pressure at the outlet 116 during operation). Consequently, the spring 140 must be specifically designed to meet the operating environment required by the specific application in which the known slam-shut valve 100 is used. More specifically, the spring 140 must be specifically designed to provide the appropriate biasing force necessary to accommodate the operating environment of the known slam-shut valve 100. However, when the operating environment changes (e.g., when the pressure at the outlet 116 increases or decreases), the closing force required to keep the valve plug 132 closed (i.e., in contact with the valve seat 120) also changes. Consequently, the spring 140 may need to be adjusted or removed and replaced with a different spring 140 better suited to the changed operating environment. Because the operating environments are often different, many different types of springs 140 must be specifically designed for use with known slam-shut valves 100 .

[0055] Secondly, because the valve stem 128, valve plug 132, and piston 136 are rigidly connected (via a threaded connection), the concentricity tolerances of each of the valve stem 128, valve plug 132, and piston 136 must be stacked during the manufacturing process. In other words, the valve stem 128, valve plug 132, and piston 136 are subject to tighter geometric tolerance requirements. This, in turn, increases the difficulty and cost of manufacturing these components and increases friction between the trim assembly 108 and the valve body 104 and bonnet 105 during operation of the conventional slam-shut valve 100, which in turn reduces the accuracy of the conventional slam-shut valve 100.

[0056] The present disclosure relates to a pressure trim assembly that addresses these and other issues with the known slam shut valve 100 (and other known slam shut valves). Similar to the trim assembly 108 of the known slam shut valve 100, the pressure trim assembly of the present disclosure generally includes a valve seat, a valve stem, a valve plug, and a piston. However, the pressure trim assembly of the present disclosure differs from the trim assembly 108 in several important respects in structure and function.

[0057] Importantly, the pressure trim assembly of the present disclosure is designed so that the valve plug of the pressure trim assembly is balanced. Thus, when the pressure trim assembly is used in a slam shut valve having a valve body, and when the valve plug is against the valve seat, a first side of the valve plug is subjected to a first force and a second side is subjected to a second force that is equal to (or substantially equal to) the first force. This is true regardless of the exact pressures at, for example, the outlet and inlet of the valve body. In other words, the closing force required to hold the valve plug against the valve seat is independent of the pressure at the inlet and / or the pressure at the outlet, which is particularly advantageous when the slam shut valve is used for high-pressure fluids. This also allows the pressure trim assembly to employ the same spring regardless of the specific operating environment required for the specific application in which the slam shut valve is employed.

[0058] In addition, in the pressure trim assembly of the present disclosure, the valve stem, valve plug and piston are connected to each other in a less rigid manner than that used in the known emergency shut-off valve 100 (and other known valves). More specifically, the valve stem, valve plug and piston are connected to each other using two U-shaped segmented connections. The U-shaped segmented connection has significantly smaller geometric tolerance requirements than the rigid connection used in the known emergency shut-off valve 100, for example. Furthermore, the valve stem, valve plug and piston are easier to manufacture and assemble, and the cost is also lower. The use of the U-shaped segmented connection also reduces the friction between the pressure trim components and the valve body when the pressure trim assembly is used in the emergency shut-off valve and when the emergency shut-off valve is in operation. This in turn improves the precision of the emergency shut-off valve using the pressure trim assembly.

[0059] Figure 3 to Figure 12 An example of a valve 300 employing a pressure trim assembly 304 constructed in accordance with the teachings of the present disclosure is shown. The valve 300 in this example is a slam-shut valve that includes a valve body 308, a bonnet assembly 312 coupled to the valve body 308, and a pressure trim assembly 304 that is movably disposed within the valve body 308 and the bonnet assembly 312. In this example, the slam-shut valve 300 also includes an annular flange 316 coupled to the valve body 308 (e.g., via a plurality of fasteners 318) to help retain the components of the pressure trim assembly 304 within the valve body 308. However, in other examples, the slam-shut valve 300 may be a rotary valve or other type of valve and / or may include different, additional, or fewer components.

[0060] Figure 3 and Figure 4 As best shown, the valve body 308 includes a fluid inlet 324, a fluid outlet 328, and a fluid passage 332 extending between and in fluid communication with the fluid inlet 324 and the fluid outlet 328. Figure 4As best shown, the bonnet assembly 312 includes a bonnet 350 coupled to the valve body 308, a spring case 354 coupled to the bonnet 350, and a cover 358 coupled to the spring case 354. In this example, the bonnet 350 is directly coupled to the valve body 308 (e.g., via a plurality of fasteners 362) and defines a central bore 366 extending along a central axis 370 of the bonnet assembly 312. Similarly, the spring case 354 is directly coupled to the bonnet 350 and also defines a central bore 374 extending along the central axis 370. Thus, at least in this example, the central bore 374 is coaxial with the central bore 366, and the central bore 366 and the central bore 374 together define a piston chamber 372. In this example, the spring case 354 is threadedly coupled to the bonnet 350 via one or more external threads provided on a lower exterior surface of the spring case 354, which matingly engage one or more internal threads provided on an upper interior surface of the bonnet 350. However, in other examples, the spring case 354 can be coupled to the valve cover 350 in a different manner. Finally, in this example, the cover 358 is threadedly coupled to the spring case 354 by one or more external threads disposed on a lower exterior surface of the cover 358 and matingly engaging one or more internal threads disposed on an upper interior surface of the spring case 354. However, in other examples, the cover 358 can be coupled to the spring case 354 in a different manner. Regardless, when the cover 358 is coupled to the spring case 354, the cover 358 is removed from the spring case 354 (at least at Figure 4 374 (and piston chamber 372).

[0061] The pressure trim assembly 304 includes a valve seat 400 and a valve plug 404. The valve seat 400, in this example, is a seat ring and is disposed in an annular port 408 formed in the fluid passage 332. In this example, the valve seat 400 is removably disposed in the valve body 308 and is retained in the valve body by a portion of the pressure trim assembly 304. In this example, the valve seat 400 is constructed of polytetrafluoroethylene (PFTE). However, in other examples, the valve seat 400 may be fixedly disposed (e.g., welded) in the valve body 308 and / or formed of a different material. Regardless, when the valve seat 400 is disposed in the annular port 408, the valve seat 400 is centered about a central axis 410 of the valve body 308, which is coaxial with the central axis 370. Furthermore, when the remainder of the pressure trim assembly 304 is disposed in the valve body 308, the valve plug 404 is generally movable relative to the valve seat 400 along the axis 410 to control fluid flow through the slam-shut valve 300. More specifically, the valve plug 404 can be positioned along the axis 410. Figure 4 The fully open position shown and Figure 11 The valve plug 404 moves between the closed positions shown, wherein the valve plug 404 is spaced a maximum distance from the valve seat 400 in the fully open position and abuts against the valve seat 400 in the closed position.

[0062] like Figure 5A 、 Figure 5B 、 Figure 5C 、 Figure 5D As best shown, the valve plug 404 generally includes a plug body 412, a plug plate 416, and a balancing port 420. The plug body 412 has a first end 432, a second end 436 opposite the first end 432, and a generally cylindrical wall 440 extending between the first end 432 and the second end 436. The plug plate 416 is disposed in the plug body 412 between the first end and the second end. In this example, the plug plate 416 is an annular plate disposed in the plug body 412 at a position closer to the first end 432 than to the second end 436. However, in other examples, the plug plate 416 can be located at or proximate to the first end 432, or closer to the second end 436 than to the first end 432. The balancing port 420 is formed through the plug plate 416 and is fluidly connected to the first end 432 and the second end 436. In other words, the first end 432 is fluidly connected to the second end 436 through the balancing port 420 (and vice versa). Through Figure 4 and Figures 5C to 5F In a side-by-side comparison, it will be appreciated that in this example, the balancing port 420 extends along an axis 444 that is offset from the central axis 410 (and therefore the central axis 370 ).

[0063] refer to Figures 5A to 5FThe valve plug 404 generally further includes a boss 424, a plug hole 426, and a plug slot 428. The boss 424 is generally disposed near the first end 432 or the second end 436 of the plug body 412. In this example, the boss 424 is disposed at the first end 432 of the plug body 412 and extends radially inward from the first end 432 of the plug body 412. However, in other examples, the boss 424 may be spaced from but proximate to the first end 432, disposed at or proximate to the second end 436, or located at a different location along the valve plug 404. In this example, the plug hole 426 is formed in the plug boss 424 (such that the plug hole 426 is located at the first end 432 of the plug body 412) and has a lock shape. The plug slot 428 is generally formed or defined between the plug plate 416 and the boss 424. In this example, the plug groove 428 is defined between the plug plate 416, the boss 424 (and the hole 426), and the generally cylindrical wall 440 located between the first end 432 and the balancing port 420, such that the plug groove 428 is a waist-shaped radial groove formed within the valve plug 404. However, in other examples, the shape of the plug groove 428 can vary while still facilitating the desired U-shaped segmented connection. Furthermore, similar to the balancing port 420, in this example, the plug groove 428 is centered about an axis that is offset from the central axis 410 (and therefore the central axis 370). Furthermore, the diameter of the plug groove 428 is greater than the diameter of the balancing port 420. The diameter of the plug groove 428 can be greater or less than the diameter of the plug hole 426.

[0064] Now go to Figures 6A to 6F, the pressure trim assembly 304 also includes a piston 450 movable along the central axis 370 within the piston chamber 372. In this example, the outer diameter of the piston 450 is larger than the outer diameter of the valve plug 404. The piston 450 generally includes a piston body 454, a piston boss 458, a piston bore 460, and a piston groove 462. The piston body 454 has a first end 466 and a second end 470 opposite the first end 466. The boss 458 is generally disposed near the first end 466 or the second end 470. In this example, the boss 458 is disposed at the first end 466 of the piston body 454 and extends radially inward from the first end 466 of the piston body 454. However, in other examples, the boss 458 may be proximate to the first end 466, at the second end 470, or proximate to the second end 470, or at a different location along the piston 450. In this example, piston bore 460 is formed in piston boss 458 (such that piston bore 460 is located at first end 466 of piston body 454) and has a lock-like shape, similar to plug hole 426. Piston groove 462 is at least partially defined by boss 458. In this example, piston groove 462 is formed within piston body 454, such that piston groove 462 is defined by and located between the interior of piston body 454, boss 458 (and piston bore 460), and first end 466 of piston body 454. Furthermore, piston groove 462 is a kidney-shaped radial groove that mirrors the shape of plug groove 428. However, in other examples, the shape of piston groove 462 can vary while still facilitating the desired U-shaped segmented connection. Similar to plug groove 428, in this example, piston groove 462 is centered about an axis that is offset from central axis 370 (and therefore central axis 410). It should also be understood that the diameter of piston groove 462 can be smaller or larger than the diameter of piston bore 460.

[0065] Now go to Figure 7 The pressure trim assembly 304 further includes a valve stem 500 extending and movable along the central axis 370 and the central axis 410. The valve stem 500 has a first end 504 movably disposed in the valve body 308, a second end 508 opposite the first end 504 and movably disposed in the bonnet assembly 312, and a variable outer diameter between the first and second ends 504, 508. In this example, the second end 508 is threaded, while the first end 504 is unthreaded. However, in other examples, the first end 504 may be threaded and / or the second end 508 may not be threaded. The valve stem 500 also has a first annular groove 512 spaced from but proximate to the first end 504. The valve stem 500 also has a second annular groove 516 formed on the (threaded) second end 508 and proximate to the second end 508. However, in other examples, the second annular groove 516 may be spaced from the second end 508.

[0066] The valve stem 500 is coupled to both the valve plug 404 and the piston 450. However, consistent with the above discussion, the valve stem 500 is not rigidly coupled to either the valve plug 404 or the piston 450. Instead, the valve stem 500 is coupled to the valve plug 404 using a first U-shaped segmented connection, and the valve stem 500 is coupled to the piston 450 using a second U-shaped segmented connection. The first U-shaped segmented connection is generally formed by the interaction between the plug boss 424, the plug groove 428, the first end 504 of the valve stem 500, and the first annular groove 512. Simultaneously, the second U-shaped segmented connection is generally formed by the interaction between the piston boss 458, the piston groove 462, the second end 508 of the valve stem 500, and a pair of valve stem connectors 520 coupled (e.g., threaded) to the second end 508 of the valve stem 500 and retained in the second annular groove 516.

[0067] More specifically, if Figure 7 As best shown, the first U-shaped segmented connection is formed by: (i) axially positioning the first end 504 of the valve stem 500 such that the first end 504 is disposed in and extends through the plug bore 426, disposed in the plug groove 428, and in contact with (or immediately adjacent to) the top side 526 of the plug plate 416; and then (ii) radially positioning the valve plug 404 such that the boss 424 of the valve plug 404 engages the valve stem 500. More specifically, the valve plug 404 is radially positioned such that the boss 424 of the valve plug 404 is captured within the first annular groove 512. Consequently, the first end 504 of the valve stem 500 is fully disposed in the plug groove 428 and is securely retained therein between the boss 424 of the valve plug 404 and the top side 526 of the plug plate 416. It should be appreciated that the boss 424 of the valve plug 404 thus prevents the first end 504 of the valve stem 500 from being inadvertently removed from the plug groove 428. Similarly, the second U-shaped segmented connection is formed by: (iii) axially positioning the second end 508 of the valve stem 500 such that the second end 508 is disposed in and extends through the piston bore 460, disposed in the piston groove 462, and in contact with (or in close proximity to) the interior of the piston body 452, and then (iv) radially positioning the valve plug 404 such that the boss 458 of the piston 450 engages a portion of the valve stem 500 directly below the stem connector 520, and such that the stem connector 520, disposed in the second annular groove 516, is captured in the piston groove 462. Consequently, the second end 508 of the valve stem 500 is fully disposed in the piston groove 462 and is securely retained within the piston groove 462 between the boss 458 of the piston 450 and the interior of the piston body 452. It should be understood that the stem connector 520, in turn, engages the top side 528 of the boss 458 of the piston 450, thereby preventing the second end 508 of the valve stem 500 from being inadvertently removed from the piston groove 462. It should also be understood that, depending on the specific assembly method of the pressure trim assembly 304, the second U-shaped segment connection can be formed before or after the first U-shaped segment connection.

[0068] like Figure 4 and Figures 8A to 8C As best shown, the pressure trim assembly 304 further includes an actuator rod 530 and a guide plate 534, and the bonnet assembly 312 further includes a cover plate 538. The actuator rod 530 is movably disposed in the bonnet assembly 312. More specifically, the actuator rod 530 extends and is movable along the central axis 370. The actuator rod 530 has a first end 550 coupled to the piston 450 and a second end 554 opposite the first end 550 and movably disposed in the housing 358. The guide plate 534 is configured to encourage the valve stem 500 to move axially (along the central axes 370, 410) but prevent the valve stem 500 from moving radially. Figure 8B and Figure 8C As best shown, the guide plate 534 in this example has a base 558, a flange 562, and a guide hole 566. The base 558 of the guide plate 534 is positioned within the valve body 308, while the flange 562, extending outward from the base 558, abuts against the outer surface of the valve body 308. Thus, the flange 562 is surrounded by the valve cover 350. The guide hole 566 is sized to accommodate the valve stem 500 and guide it in the manner described above. Furthermore, the cover 538 is trapped between the valve body 308 and the valve cover 350, thereby helping to securely hold the guide plate 534 in a desired position relative to the valve stem 500. Furthermore, while not explicitly described herein, it should be understood that one or more sleeves may be positioned between the guide plate 534 and the valve stem 500 to help maintain the valve stem 500 in a desired position relative to the guide plate 534.

[0069] Now go to Figure 9A and Figure 9B, the pressure trim assembly 304 also includes a plug cap 570. The plug cap 570 is generally configured to retain the valve plug 404 in the valve body 308 and guide the valve plug 404 for movement along the central axis 410. In this example, the plug cap 570 has a base 578, a flange 582, a cap aperture 586 defined by the base 578, and a seat retainer 590. The base 578 is generally U-shaped and is sized to be disposed within the valve body 308 and the annular flange 316. The flange 582 is coupled to a central portion of the base 578 and extends outwardly therefrom such that the flange 582 is positioned to engage a portion of the annular flange 316, which in turn helps to secure the plug cap 570 relative to the valve body 308 and the annular flange 316. The cap aperture 586 is generally sized to receive part or all of the valve plug 404 as the valve plug 404 moves relative to the valve seat 400, such that the plug cap 570 partially or completely surrounds the valve plug 404 (depending on the exact positioning of the valve plug 404). Finally, a seat retainer 590 is disposed at or proximate one end of the plug cap 570. Thus, when the plug cap 570 is disposed in the valve body, the seat retainer 590 is positioned to engage the valve seat 400, thereby securely retaining the valve seat 400 in the annular port 408 formed in the fluid passageway 332.

[0070] Back to Figure 4 , the pressure trim assembly 304 further includes a spring 600 configured to bias a top side 601 of the piston 450 in a direction toward the valve seat 400. In other words, the spring 600 is configured to bias the valve plug 404 to an open position (in which the valve plug 404 is spaced apart from the valve seat 400). In this example, the spring 600 is disposed within the valve cover assembly 312, with a first end of the spring 600 resting against the piston 450 (more specifically, against the top side 601) and a second end of the spring 600 resting against the spring case 354. However, in other examples, the spring 600 may rest against one or more different components of the valve cover assembly 312 while still biasing the top of the piston 450 in a direction toward the valve seat 400.

[0071] It should be understood that the slam shut valve 300 also includes a plurality of sealing elements arranged to facilitate sealing various components of the slam shut valve 300. For example, the valve seat 400 includes a sealing element 602A (e.g., an O-ring) disposed about an outer surface of the valve seat 400 and sealingly engaging a portion of the valve body 308 in the annular port 408 to form a seal between the valve seat 400 and the valve body 308. Figure 5A and 5C As best shown, the valve plug 404 includes a sealing element 602B (e.g., an O-ring) disposed in a first groove formed on the outer surface of the plug body 412, and a pair of backup rings 602C, 602D also disposed in first and second grooves formed on the outer surface of the plug body 412. Figure 10As best shown in FIG, sealing element 602B and backup rings 602C, 602D are positioned to sealingly engage plug cap 570 to form a seal between valve plug 404 and plug cap 570. More specifically, sealing element 602B and backup rings 602C, 602D engage the inner surface of base 578 of plug cap 570. Similarly, piston 450 includes a pair of sealing elements 602E (e.g., O-rings) disposed in first and second grooves, respectively, formed in the outer surface of piston body 454, and a pair of backup rings 602F, also disposed in first and second grooves, respectively, formed in the outer surface of piston body 454. Thus, sealing elements 602E and backup rings 602F are positioned to sealingly engage valve cap 350 to form a seal between piston 450 and valve cap 350. Furthermore, plug cap 570 includes a sealing element 602G (e.g., O-ring) disposed on the outer surface of flange 582 and configured to sealingly engage a portion of valve body 308 to form a seal therebetween. The slam shut valve 300 may also include additional sealing elements, such as a sealing element between the valve body 308 and the valve cover 350, a sealing element disposed on an outer surface of the guide plate 534 and configured to sealingly engage a portion of the valve body 308 to form a seal therebetween, and one or more sealing elements disposed between the guide plate 534 and the valve stem 500.

[0072] It should also be understood that the emergency shut-off valve 300 also includes one or more pressure ports. Figure 3A 、 3BAs best shown in Figures 4, 11, and 12, the slam-shut valve 300 includes three pressure ports: a first pressure port 604A formed in the valve cover 350, a second pressure port 604B also formed in the valve cover 350, and a third pressure port 604C formed in the spring case 354. The first pressure port 604A is fluidly coupled to a ball valve 608 located downstream of the slam-shut valve 300, such that the first pressure port 604A is fluidly coupled to the downstream pressure (i.e., the pressure downstream of the slam-shut valve 300). Furthermore, the first pressure port 604A facilitates fluid communication between the downstream ball valve 608 and the first portion of the piston chamber 372 defined between the bottom side 603 of the piston 450 and the cover plate 538. In other words, the first portion of the piston chamber 372 is fluidly coupled to the downstream pressure via the first pressure port 604A. The second pressure port 604B is fluidly coupled to the pilot valve 612, also located downstream of the slam-shut valve 300, such that the second pressure port 604B is also fluidly coupled to the downstream pressure. Furthermore, second pressure port 604B facilitates fluid communication between pilot valve 612 and the first portion of piston chamber 372. In other words, the first portion of piston chamber 372 will also be fluidically coupled to the downstream pressure via second pressure port 604B (the downstream pressure for fluid coupling to second pressure port 604B is the same as the downstream pressure for fluid coupling to first pressure port 604A). Third pressure port 604C, on the other hand, facilitates fluid communication with the second portion of piston chamber 372 defined between spring case 354 and top side 601 of piston 450. Third pressure port 604C is typically fluidically coupled to atmosphere, in which case the second portion of piston chamber 372 will be fluidically coupled to atmospheric pressure via third pressure port 604C. However, in other examples, slam shut valve 300 may include only one pressure port (e.g., first pressure port 604A), three or more pressure ports, and / or any one of the pressure ports may be located in different locations. In yet another example, first pressure port 604A and / or second pressure port 604B may be coupled to different pressure sources.

[0073] In operation, the piston 450 can move within the piston chamber 372 in response to downstream pressure, which, as described above, is fluidly coupled to the piston chamber 372 via the first pressure port 604A and the second pressure port 604B. When the downstream pressure is within a predetermined range (e.g., below an upper pressure limit), the force exerted by the downstream pressure (via the first pressure port 604A) on the bottom side 603 of the piston is less than the biasing force exerted by the spring 600, and the piston 450 moves downward (at least in this direction), causing the valve stem 500 to move downward (at least in this direction). The downward movement of the valve stem 500 causes the valve plug 404 to disengage and move away from the valve seat 400 into a fully open position (or an intermediate open position), thereby allowing fluid to flow through the fluid passage 332, as shown in FIG. Figure 4As shown, the emergency shut-off valve 300 is in the open position. On the contrary, in response to the downstream pressure falling outside the predetermined range (for example, higher than the upper pressure limit), the force exerted by the downstream pressure on the bottom side 603 of the piston 450 exceeds the biasing force exerted by the spring 600, and the piston 450 moves upward (at least in this direction), causing the valve stem 500 to move upward (at least in this direction). The upward movement of the valve stem 500 causes the valve plug 404 to move toward the valve seat 400, contacting the valve seat 400 and entering the closed position, thereby cutting off the flow of fluid through the fluid channel 332, as shown in FIG. Figure 11 As shown, the slam shut valve 300 is in the closed position. When the valve plug 404 abuts the valve seat 400, the first end 432 of the plug body 412 is subjected to the force generated by the pressure at the fluid outlet 328. However, because the valve plug 404 is balanced, the underside of the plug plate 416 and the second end 436 of the plug body 412 are in fluid communication with the first end 432 of the plug body 412 via the plug hole 426, the plug groove 428, and the balancing port 420. Therefore, the second end 436 of the plug body 412 (and the underside of the plug plate 416) are subjected to the same force (generated by the pressure at the fluid outlet 328). Furthermore, consistent with the discussion above, the same spring—spring 600—can be used regardless of the specific operating environment associated with the slam shut valve 300 (e.g., the specific pressures at the fluid inlet 324 and / or the fluid outlet 328).

[0074] Figure 13 Another example of a valve 1200 constructed in accordance with the teachings of the present disclosure is shown. Valve 1200 is similar to valve 300 in that valve 1200 is also a slam-shut valve that includes a valve body 1208, a bonnet assembly 1212, and a pressure trim assembly 304. While valve body assembly 1208 and bonnet assembly 1212 are similar to valve body assembly 308 and bonnet assembly 312, respectively, slam-shut valve 1200 is oriented differently than slam-shut valve 300. More specifically, slam-shut valve 1200 is oriented such that the valve plug 404, piston 450, and valve stem 500 of pressure trim assembly 304 move in a direction opposite to that in which they move when used in slam-shut valve 300. For example, in slam-shut valve 1200, downward movement of piston 450 and valve stem 500 causes valve plug 404 to move to a closed position (rather than an open position as in slam-shut valve 300). Orienting the slam-shut valve 1200 in this manner helps prevent liquid from accumulating in the plug cap 570 , for example, because the liquid is directed out of the plug cap 570 and into the fluid passage 332 , rather than remaining stationary in the plug cap 570 and potentially interfering with normal movement of the valve plug 404 .

[0075] Figure 14Another example of a valve 1300 that can employ a pressure trim assembly 1304 constructed according to the teachings of the present disclosure is shown. Valve 1300 is similar to valve 300 in that valve 1300 is also a slam shut valve, including a valve body 1308, a valve cover assembly 1312, and a pressure trim assembly 1304, which also includes a valve seat 1314, a valve plug 1316, a piston 1320, and a valve stem 1324 that are substantially similar to valve seat 400, valve plug 404, piston 450, and valve stem 500, respectively. However, slam shut valve 1300 differs in several respects. First, pressure trim assembly 1304 does not include a guide plate (e.g., guide plate 534). Instead, pressure trim assembly 1304 includes a cover plate 1328 that is solely responsible for preventing radial movement of valve stem 1324. Second, while pressure trim assembly 1304 includes a plug cap 1332 for receiving and retaining valve plug 1316, similar to pressure trim assembly 304, plug cap 1332 is trapped between valve body 1308 and bonnet 1336 of bonnet assembly 1312, such that, in this example, plug cap 1320 engages bonnet 1316. Third, while pressure trim assembly 1304 also includes a piston chamber 1338 for movably receiving piston 1320, piston chamber 1338 is defined solely by the central aperture of spring case 1340 of bonnet assembly 1312. Fourth, while slam-shut valve 1300 includes a flange 1344 similar to flange 316, in this example, flange 1344 is coupled to spring case 1340 and serves as a cover for bonnet assembly 1312 and piston chamber 1336. Fifth, in this example, valve seat 1314 is located below valve plug 1316 and plug cap 1332. Thus, as in slam shut valve 1200 , during operation of slam shut valve 1300 , downward movement of piston 1320 and valve stem 1324 causes valve plug 1316 to move to a closed position (rather than an open position as was the case in slam shut valve 300 ).

[0076] Finally, it should be understood that many components of the valves described herein (e.g., slam-shut valve 300) are typically made of one or more metallic materials. Preferably, the valve plug 404, piston 450, and valve stem 500 are made of one or more materials that are resistant to hydrogen corrosion. Furthermore, preferably, any components of the valves described herein (e.g., slam-shut valve 300) that are not made of any metallic material are also made of one or more non-metallic materials that are not soluble in hydrogen.

[0077] Preferred embodiments of the present disclosure are described herein, including the best mode of implementing the present disclosure known to the inventors. Although many examples are shown and described herein, it will be readily understood by those skilled in the art that the details of the various embodiments do not necessarily exclude each other. On the contrary, after reading the teachings herein, those skilled in the art should be able to combine one or more features of an embodiment with one or more features of the remaining embodiments. In addition, it should be understood that the illustrated embodiments are merely exemplary embodiments and should not be considered to limit the scope of the present disclosure. The use of any and all examples or exemplary language (e.g., "for example") provided herein is intended solely to better illustrate these aspects of the exemplary embodiments of the present disclosure, rather than to limit the scope of the present disclosure. Any language in this specification should not be construed as indicating that any non-required element is necessary for the implementation of the present disclosure.

Claims

1. A valve trim assembly for use in a valve, the valve trim assembly comprising: a valve plug comprising a plug body having a first end and a second end opposite the first end, a plug plate disposed in the plug body between the first end and the second end, a balancing port formed through the plug plate and fluidly connecting the first end and the second end, a boss disposed proximate to the first end, and a plug groove formed between the plug plate and the boss; a piston comprising a piston body having a first end and a second end opposite the first end, a boss disposed proximate the first end, and a piston groove formed in the piston body, the piston groove being partially defined by the boss; and A valve stem is coupled to the valve plug and the piston, the valve stem having a first end and a second end opposite the first end, the first end being securely disposed in the plug groove and the second end being securely disposed in the piston groove.

2. The valve trim assembly according to claim 1, wherein: The valve stem includes an annular groove formed adjacent the first end of the valve stem, and wherein the boss of the valve plug is arranged to be disposed in the annular groove to securely retain the first end of the valve stem in the plug groove.

3. The valve trim assembly according to claim 1 or 2, wherein: Also included is a valve stem connector coupled to the second end of the valve stem, wherein the valve stem connector is arranged to engage the boss of the piston to securely retain the second end of the valve stem in the piston groove.

4. The valve trim assembly according to claim 3, wherein: The valve stem connector is threadably connected to the second end of the valve stem.

5. The valve trim assembly according to claim 3 or 4, wherein: The valve stem includes a second annular groove formed proximate the second end of the valve stem, and wherein the valve stem connector is disposed in the second annular groove.

6. The valve trim assembly according to any one of claims 1 to 5, wherein: Also included is a guide plate coupled to the valve stem between the first end and the second end of the valve stem, the guide plate being configured to prevent radial movement of the valve stem.

7. The valve trim assembly according to any one of claims 1 to 6, wherein: The diameter of the balancing port is smaller than the diameter of the plug slot.

8. The valve trim assembly according to any one of claims 1 to 7, wherein: Also includes: a valve seat adapted to be disposed in a valve body of the valve; a plug cap surrounding the valve plug; and one or more sealing elements carried by the valve plug, the one or more sealing elements being disposed between an outer surface of the valve plug and the plug cap; The valve plug is movable relative to the valve seat to control the flow of fluid through the valve trim assembly.

9. The valve trim assembly according to any one of claims 1 to 8, wherein: The plug groove and the piston groove are both radial grooves oriented in the radial direction.

10. A valve comprising a valve body, a valve trim assembly, and a cover plate assembly coupled to the valve body, wherein: The valve body includes an inlet, an outlet, and a fluid passage connecting the inlet and the outlet; The valve trim assembly comprises: a valve seat disposed in the fluid passage of the valve body; a valve plug movable relative to the valve seat to control the flow of fluid through the fluid passage, the valve plug comprising: a plug body having a first end and a second end opposite to the first end, a plug plate disposed in the plug body between the first end and the second end, a balancing port formed through the plug plate and fluidically connecting the first end and the second end, a boss disposed proximate to the first end, and a plug groove formed between the plug plate and the boss; a piston comprising a piston body having a first end and a second end opposite the first end, a boss disposed proximate the first end, and a piston groove formed in the piston body, the piston groove being partially defined by the boss; and a valve stem coupled to the valve plug and the piston, the valve stem having a first end and a second end opposite the first end, the first end securely disposed in the plug groove and the second end securely disposed in the piston groove; and The cover plate assembly includes a piston chamber, wherein the piston is movably disposed in the piston chamber.

11. The valve according to claim 10, wherein A spring is also included, one end of the spring abuts against the piston, and the other end of the spring abuts against the cover plate assembly.

12. The valve according to claim 10 or 11, wherein Also included is a guide plate constrained between the cover plate assembly and the valve plug, wherein the guide plate is coupled to the valve stem between the first end and the second end of the valve stem to prevent radial movement of the valve stem.

13. A valve according to any one of claims 10 to 12, wherein: The valve stem includes an annular groove formed adjacent the first end of the valve stem, and wherein the boss of the valve plug is arranged to be disposed in the annular groove to securely retain the first end of the valve stem in the plug groove.

14. A valve according to any one of claims 10 to 13, wherein Also included is a valve stem connector coupled to the second end of the valve stem, wherein the valve stem connector is arranged to engage the boss of the piston to securely retain the second end of the valve stem in the piston groove.

15. The valve according to claim 14, wherein The valve stem connector is threadably connected to the second end of the valve stem.

16. A valve according to claim 14 or 15, wherein The valve stem includes a second annular groove formed proximate the second end of the valve stem, and wherein the valve stem connector is disposed in the second annular groove.

17. A valve according to any one of claims 10 to 16, wherein The diameter of the balancing port is smaller than the diameter of the plug slot.

18. A valve according to any one of claims 10 to 17, wherein Also includes: a plug cap surrounding the valve plug; and One or more sealing elements are carried by the valve plug, and are disposed between an outer surface of the valve plug and the plug cap.

19. A valve according to any one of claims 10 to 18, wherein The plug groove and the piston groove are both radial grooves oriented in the radial direction.

20. A method of forming a valve, the method comprising: obtaining a valve body comprising an inlet, an outlet, and a fluid passage connecting the inlet to the outlet; positioning a valve seat in the fluid passage of the valve body; Positioning a valve plug in the cavity of the valve body, the valve plug comprising: a plug body having a first end and a second end opposite the first end, a plug plate disposed in the plug body between the first end and the second end, a balancing port formed through the plug plate and fluidically connecting the first end and the second end, a boss disposed proximate to the first end, and a plug groove formed between the plug plate and the boss; obtaining a piston comprising a piston body having a first end and a second end opposite the first end, a boss disposed proximate the first end, and a piston groove formed in the piston body, the piston groove being partially defined by the boss; securely disposing the first end of the valve stem in the plug groove by axially positioning the first end of the valve stem in the plug groove and radially positioning the valve plug so that the boss of the valve plug engages the first end of the valve stem; and The second end of the valve stem is securely positioned in the piston groove by axially positioning the second end of the valve stem in the piston groove and radially positioning the piston so that the boss of the piston engages with a portion of the valve stem proximate the second end of the valve stem.

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