Corrosion-resistant valve trim

Abstract

A valve trim for a fluid flow control device. The valve trim includes a valve cage body defined by an outer valve cage wall and an inner valve cage wall coupled to the outer valve cage wall, the outer valve cage wall spaced radially outward from the inner valve cage wall. The valve trim further includes a plurality of first flow feature passages formed in the outer valve cage wall, and a plurality of second flow feature passages formed in the inner valve cage wall. The valve cage body is at least partially made of a corrosion resistant material.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 909,660, filed October 2, 2019, and U.S. Provisional Application No. 62 / 909,164, filed October 1, 2019. The entire disclosure of each of these applications is incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to fluid pressure reducing devices, and more specifically, to corrosion-resistant valve internals for fluid flow control devices. Background Technology

[0004] In process control systems (such as distributed or scalable process control systems commonly found in chemical, petroleum, power generation, or other industrial processes), it is often necessary to reduce fluid pressure. In some cases, the fluid pressure must be reduced significantly. Where a relatively high pressure drop is required, the pressure drop ratio (pressure change divided by inlet pressure) can be very high.

[0005] Generally, pressure drop typically causes an increase in unwanted noise and / or vibration levels. These problems can be even more pronounced in applications with relatively high pressure drop ratios. To prevent or at least reduce noise and vibration, process systems often use flow-limiting devices to reduce the pressure drop ratio and also the fluid pressure. Such flow-limiting devices include, for example, valve internals, diffusers, and silencers.

[0006] However, known valve internals are typically made of materials highly susceptible to pressure drops and corrosion from the fluids flowing through them. This is especially true when these valve internals are used in dirty service applications (i.e., applications involving harsh flow conditions, such as fine catalyst powder in oil refineries, magnetite in power plants, and sand in oil production where the fluid becomes contaminated). In fact, when the fluid flowing through one of these valve internals becomes contaminated (e.g., including particulate matter), the fluid tends to corrode the valve internal rapidly. This, in turn, requires frequent maintenance, which can be quite expensive and may necessitate shutting down the process control system (or a portion thereof). Summary of the Invention

[0007] According to an exemplary aspect of the present invention, a valve internal for a fluid flow control device is provided. The valve internal includes a valve cage body having a first end and a second end opposite to the first end. The valve cage body is defined by an outer valve cage wall and an inner valve cage wall coupled to the outer valve cage wall, the outer valve cage wall being radially spaced outward from the inner valve cage wall. The valve internal also includes a fluid pressure-reducing portion. The fluid pressure-reducing portion includes a plurality of first flow characteristic passages formed in the outer valve cage wall and a plurality of second flow characteristic passages formed in the inner valve cage wall. The valve internal also includes a valve seat carried by the valve cage body, the valve seat being adjacent to but upstream of the second end of the valve cage body, such that the valve seat is isolated from the fluid pressure-reducing portion.

[0008] According to another exemplary aspect of the invention, a valve internal for a fluid flow control device is provided. The valve internal includes a valve cage body defined by an outer valve cage wall and an inner valve cage wall coupled to the outer valve cage wall, the outer valve cage wall being radially spaced outward from the inner valve cage wall. The valve internal also includes a plurality of first flow characteristic passages formed in the outer valve cage wall and a plurality of second flow characteristic passages formed in the inner valve cage wall. The valve cage body is at least partially made of a corrosion-resistant material.

[0009] According to another exemplary aspect of the present invention, a fluid flow control device is provided. The fluid flow control device includes a valve body, the valve body including a valve body inlet, a valve body outlet, and a channel extending between the valve body inlet and the valve body outlet. The fluid flow control device further includes a valve internal at least partially disposed in the channel of the valve body. The valve internal includes a valve cage body defined by an outer valve cage wall and an inner valve cage wall coupled to the outer valve cage wall, the outer valve cage wall being radially spaced outward from the inner valve cage wall. The valve internal also includes a plurality of first flow characteristic passages formed in the outer valve cage wall and a plurality of second flow characteristic passages formed in the inner valve cage wall. The valve cage body is at least partially made of a corrosion-resistant material.

[0010] According to another exemplary aspect of the present invention, a method for manufacturing valve internals for a fluid flow control device is provided. The method includes using additive manufacturing techniques to generate an outer valve cage element, the outer valve cage element including a plurality of first flow characteristic passages. The method further includes using additive manufacturing techniques to generate an inner valve cage element, the inner cage element being formed of a corrosion-resistant material and including a plurality of second flow characteristic passages. The method further includes coupling the outer valve cage element to the inner valve cage element to form a valve cage body having an outer wall defined by the outer valve cage element and an inner wall defined by the inner valve cage element.

[0011] Furthermore, according to any one or more of the foregoing exemplary aspects of the present invention, the valve internals, fluid flow control device, or method of manufacturing valve internals for a fluid flow control device may further include any one or more of the following preferred forms in any combination.

[0012] In a preferred embodiment, the valve cage body extends along the valve cage axis between the first end and the second end, and each of the plurality of first flow characteristic passages extends along a first axis parallel to the valve cage axis.

[0013] In another preferred embodiment, each of the plurality of second flow characteristic passages extends along a second axis parallel to the valve cage axis and the first axis.

[0014] In another preferred embodiment, the plurality of first flow characteristic pathways are spaced apart from and surround the plurality of second flow characteristic pathways.

[0015] In another preferred embodiment, the valve cage body is at least partially made of a corrosion-resistant material. The inner valve cage wall may be made of the corrosion-resistant material. Both the inner and outer valve cage walls may be made of the corrosion-resistant material.

[0016] In another preferred embodiment, the valve cage body is defined by an inner valve cage element and an outer valve cage element coupled to the inner valve cage element, the inner valve cage element including the inner wall, and the outer valve cage element including the outer wall.

[0017] In another preferred embodiment, the upper valve cage element is coupled to the inner valve cage element and the outer valve cage element. The upper valve cage element may be made of a metallic material.

[0018] In another preferred embodiment, the plurality of first flow characteristic passages define a first flow area, and the plurality of second flow characteristic passages define a second flow area smaller than the first flow area.

[0019] In another preferred embodiment, the valve seat is supported by the valve cage body, and the valve plug includes a support surface that is movably disposed within the valve cage body relative to the valve seat to control fluid flow through the passage in the valve body.

[0020] In another preferred embodiment, the valve cover is coupled to the valve body, wherein the valve cover has a portion that directly engages with the upper valve cage portion. Attached Figure Description

[0021] The features of the invention considered novel are particularly set forth in the appended claims. The invention can be best understood by referring to the following description taken in conjunction with the accompanying drawings, wherein like reference numerals denote like elements in several figures, wherein:

[0022] Figure 1 This is a partial cross-sectional view of a valve internal constructed in accordance with the teachings of this disclosure and disposed in a fluid flow control device in the closed position; and

[0023] Figure 2 Similar to Figure 1 However, the fluid flow control device is shown in the fully open position.

[0024] Figure 3 yes Figure 1 A close-up view of one of the flow characteristic passages of the valve internals.

[0025] Figure 4 yes Figure 3 A sectional view taken along line 4-4. Detailed Implementation

[0026] This disclosure relates to valve internals that address these and other problems of conventional valve internals. The valve internals disclosed herein are manufactured at least partially using additive manufacturing techniques, allowing them to be easily and cost-effectively made, partially (or entirely), from corrosion-resistant materials. Furthermore, the valve internals disclosed herein have protected valve support surfaces, meaning that these surfaces are not exposed to significant pressure drops when fluid flows through them. In effect, the valve support surfaces (i.e., the shut-off ports) of the valve internals are isolated from the throttling portions of the valve internals (where fluid pressure drops occur). Therefore, when the valve internals are used in dirty service and / or high-pressure drop applications, they prevent or at least reduce noise and vibration (by reducing the pressure drop ratio and fluid pressure) while substantially resisting or withstanding the aforementioned corrosion. At least, the valve internals can resist or withstand corrosion for a longer period than conventional valve internals. Therefore, the valve internals disclosed herein have a longer service life (and thus require less frequent maintenance) and are simultaneously easier and less costly to manufacture compared to conventional valve internals.

[0027] As used herein, the phrase “additive manufacturing technology” refers to any additive manufacturing technique or process that constructs a three-dimensional object by adding successive layers of material onto a material. Additive manufacturing technology can be performed using any suitable machine or combination of machines. Additive manufacturing technology can generally involve or utilize computers, 3D modeling software (e.g., computer-aided design or CAD software), machine tools, and layered materials. Once a CAD model is generated, the machine tool can read data from the CAD file and layer or add successive layers of liquids, powders, sheet materials (e.g.,) in a layer-up-layer manner to create a three-dimensional object. Additive manufacturing technology can include any of several techniques or processes, such as stereolithography (“SLA”), fused deposition modeling (“FDM”), multi-jet modeling (“MJM”), selective laser sintering (“SLS”), electron beam additive manufacturing, and arc welding additive manufacturing. In some embodiments, additive manufacturing processes can include directional energy laser deposition (TELD). This directed energy laser deposition process can be performed by a multi-axis computer numerical control (“CNC”) machine tool with directed energy laser deposition capabilities.

[0028] Figure 1 and Figure 2 An example of a valve internal 100 constructed in accordance with the teachings of this disclosure and used in a fluid flow control device is shown. The valve internal 100 is a multi-stage valve internal configured to provide multi-stage fluid pressure drops in dirty servicing and / or high-pressure drop applications involving compressible fluids (e.g., gases), but it should be understood that the valve internal 100 can also be used to reduce fluid pressure in cleaning applications. The valve internal 100 typically includes a valve cage 104, a valve seat 108 carried by the valve cage 104, and a control element 112 movably disposed relative to the valve seat 108 within the valve cage 104 to control fluid flow through the valve internal 100.

[0029] The valve cage 104 includes an integral body 116 and an internal channel 120, which is completely contained within the integral body 116. The integral body 116 is manufactured at least partially using additive manufacturing techniques, allowing it to be partially (or entirely) made of corrosion-resistant materials (e.g., Ultimet, Alloy 6, high-hardness stainless steels (e.g., 420C, 440C, etc.), high-hardness steels (such as tool steel, nickel alloys (e.g., Inconel 718, K-Monel, etc.), tungsten carbide, or ceramic materials). Subsequently, at least a portion of the integral body 116 (e.g., the portion of the integral body 116 exposed to fluid flow) substantially resists corrosion from the fluid flowing through it. In some examples, the integral body 116 is made entirely of corrosion-resistant materials. However, in other examples, the integral body 116 may be made of two or more different materials (including corrosion-resistant materials and one or more suitable materials (e.g., stainless steel, aluminum)). As will be discussed in more detail below, the internal channel 120 defines multiple fluid pressure drop stages that contribute to a desired fluid pressure drop.

[0030] In this version, the monolithic body 116 typically extends along a longitudinal axis 124 from a first end 128 to a second end 132 opposite to the first end 128. The monolithic body 116 includes an outer wall 136, an inner wall 140, a flange 144, and a valve seat 108. However, in other examples, the monolithic body 116 may include more or less and / or different components. As an example, the monolithic body 116 may not include the valve seat 108, which may, for example, be removably coupled to the monolithic body 116.

[0031] When the valve internals 100 are disposed in a fluid flow control device, the outer wall 136 is typically arranged to engage the valve body of the fluid flow control device. In this example, the outer wall 136 is formed by a plurality of wall portions of different sizes (i.e., a first wall portion 152, a second wall portion 156, a third wall portion 160, and a fourth wall portion 164, and a plurality of first flow characteristic passages 166 (only two of which are shown) arranged circumferentially in the outer wall 136). The first wall portion 152 extends between the first end 128 and the flange 144 along an axis parallel to the longitudinal axis 124. The second wall portion 156 extends downward from the flange 144 (at least at... Figure 1 and Figure 2The outer wall 136 extends inward (i.e., at an angle relative to the longitudinal axis 124) towards the second end 132, terminating at or before the plurality of first flow characteristic passages 166. A third wall portion 160 extends downward from the plurality of first flow characteristic passages 166 along an axis parallel to the longitudinal axis 124, and then outward towards a shoulder 168 arranged to engage part of the valve body. A fourth wall portion 164 extends downward from the third wall portion 160 along an axis parallel to the longitudinal axis 124 to the second end 132. The diameter of the fourth wall portion 164 is smaller than the diameter of the third wall portion 160. However, in other examples, the outer wall 136 may be formed of more or less, or different sized wall portions, to accommodate and engage valve bodies of different sizes.

[0032] Meanwhile, the inner wall 140 is radially spaced inward from the outer wall 136. In this example, the inner wall 140 is also formed by a plurality of wall portions of different sizes (i.e., a first wall portion 172, a second wall portion 176, a third wall portion 180, and a fourth wall portion 184, and a plurality of second flow characteristic passages 186 (only two are shown) circumferentially arranged in the inner wall 140). The first wall portion 172 extends along an axis parallel to the longitudinal axis 124 between its first end 128 and the plurality of second flow characteristic passages 186, and is defined to be sized to receive an aperture 188 of the control element 112 therein. The second wall portion 176 extends downward from below the plurality of second flow characteristic passages 186 along an axis parallel to the longitudinal axis 124 (at least at...). Figure 1 and Figure 2 The first wall portion 176 extends downward from the second wall portion 176 along an axis parallel to the longitudinal axis 124, and then extends outward toward the second end 132 (i.e., at an angle relative to the longitudinal axis 124). The third wall portion 180 extends downward from the second wall portion 176 along an axis parallel to the longitudinal axis 124, such that the diameter of the third wall portion 180 is larger than the diameter of the first wall portion 172. The fourth wall portion 184 extends downward from the third wall portion 180 and inward toward the second end 132 (i.e., at an angle relative to the longitudinal axis 124). Therefore, the diameter of the fourth wall portion 184 is smaller than the diameter of the third wall portion 180. However, in other examples, the inner wall 140 may be formed of more or less, or different, wall portions.

[0033] Because the outer wall 136 is radially spaced outward from the inner wall 140, the outer wall 136 must be larger than the inner wall 140, and a plurality of first flow characteristic passages 166 (formed in the outer wall 136) define a first flow area that is larger than the second flow area defined by a plurality of second flow characteristic passages 186 (formed in the inner wall 140). The ratio of the first flow area to the second flow area can be, for example, 2:1, 3:1, 4:1, or some other ratio suitable for a given application. In any case, a larger first flow area helps to provide back pressure, which further helps to reduce noise and vibration. Furthermore, since the outer wall 136 is radially spaced outward from the inner wall 140, the plurality of first flow characteristic passages 166 are radially spaced outward from the plurality of second flow characteristic passages 186. Preferably, and as Figure 1 and Figure 2 As shown, multiple first flow characteristic pathways 166 surround multiple second flow characteristic pathways 186.

[0034] like Figure 1 and Figure 2 As shown, in this example, each first flow characteristic passage 166 preferably takes the form of a first groove. Figure 3 As best shown, it independently depicts one of the first slots, in this example each first slot having a constant width in the vertical or longitudinal direction (i.e., along the vertical axis 183 parallel to the longitudinal axis 124), wherein a first end or upper end of each first slot is defined by a second wall portion 156 of the outer wall 136, and a second end or bottom end of each first slot is defined by a third wall portion 160 of the outer wall 136. Meanwhile, as Figure 4 As best illustrated, each first slot in this example has a variable width in the horizontal or transverse direction (i.e., along the horizontal axis 185 that traverses the vertical axis 183 and the longitudinal axis 124). More specifically, each first slot in this example has a tapered flow path that converges from the slot inlet 187 to a middle portion where the slot has its minimum width, and then diverges from this middle portion to the slot outlet 189 (located radially outside the slot inlet 187 and in fluid communication with the fluid passage of the fluid flow control device), such that the width of the slot outlet 189 is greater than that of the slot inlet 187 (although the width of the slot outlet 189 may alternatively be less than or equal to the width of the slot inlet 187). These tapered flow paths help reduce noise of the fluid flowing through them and control the capacity of the valve internals 104.

[0035] Similarly, each second flow characteristic passage 186 preferably takes the form of a second groove. In this example, each second groove has the same shape and size as each first groove. Therefore, in this example, each second groove also has a constant width in the vertical or longitudinal direction, wherein a first end or upper end of each second groove is defined by a first wall portion 172 of the inner wall 140, and a second end or lower end of each second groove is defined by a second wall portion 176 of the inner wall 140. Likewise, in this example, each second groove also has a variable width in the horizontal or transverse direction, wherein each second groove has a conical flow path that is substantially the same as the conical flow path of each first groove. Like the conical flow path of the first groove, the conical flow path of the second groove helps to reduce noise of the fluid flowing through it and control the capacity of the valve internals 104.

[0036] Each of the grooves 166 and 186 preferably has a width equal to 1 / 16 inch in the vertical or longitudinal direction, although one or more of the grooves 166 and 186 may have a width greater or smaller in that direction, such that grooves 166 and / or 186 may have different widths in that direction. However, in other examples, the first flow characteristic passage 166 and / or the second flow characteristic passage 186 may have different shapes and / or dimensions than those shown herein. In one such example, the first flow characteristic passage 166 and / or the second flow characteristic passage 186 may alternatively take the form of holes drilled or otherwise formed in the outer wall 136 and the inner wall 140, respectively.

[0037] Flange 144 extends outward from outer wall 136. In this example, flange 144 extends outward from outer wall 136 at a position adjacent to but spaced apart from first end 128. However, in other examples, flange 144 may extend outward from outer wall 136 at a position closer to or further away from first end 128. Thus, when valve internal 100 is provided in a fluid flow control device, flange 144 is arranged to engage both valve body and valve cover of the fluid flow control device. On the other hand, valve seat 108 is supported by and extends inward from inner wall 140. In this example, valve seat 108 extends inward from fourth wall portion 184 of inner wall 140 at a position adjacent to but spaced apart from second end 132 of integral body 116. In this way, valve seat 108 is provided within internal passage 120, but located in a position isolated from the area where pressure reduction occurs, thereby protecting valve seat 108. In other examples, valve seat 108 may extend inward from inner wall 140 at a location closer to or further away from second end 132. In any case, valve seat 108 is positioned to selectively receive a portion of control element 112 to open or close internal passage 120, as will be described in more detail below.

[0038] In some examples, the monolithic body 116 can be integrally manufactured using additive manufacturing techniques, such that the components of the monolithic body 116—outer wall 136, inner wall 140, flange 144, and valve seat 108—form a single body. In one such example, the monolithic body 116 can be integrally printed or otherwise made of a corrosion-resistant material, such that the components of the monolithic body 116—outer wall 136, inner wall 140, flange 144, and valve seat 108—are made of the same corrosion-resistant material. In another such example, the monolithic body 116 can be made of two or more materials, such as a corrosion-resistant material, another different corrosion-resistant material, or a corrosion-resistant and non-corrosion-resistant material (e.g., stainless steel, aluminum, various alloys). In other examples, the monolithic body 116 can be formed from two or more elements that are manufactured separately (using additive manufacturing techniques or conventional manufacturing techniques) and then joined together (i.e., forming a non-monolithic body). In one such example, the integral body 116 can be formed by using additive manufacturing techniques to manufacture the outer valve cage element (including the outer wall 136), using additive manufacturing techniques to manufacture the inner valve cage element (including the inner wall 140), and coupling the outer valve cage element to the inner valve cage element. The outer valve cage element can be clamped, welded, threaded, mated, or coupled to the inner valve cage element, for example, in another suitable manner. Alternatively, the outer valve cage element itself can be formed from two or more different segments, which are manufactured separately and then coupled together (e.g., via printed dovetail joints). In another such example, the integral body 116 can also be formed by manufacturing an upper valve cage element (which, for example, includes a first wall portion 152 and a second wall portion 156 of the outer wall 136, and a portion of a first wall portion 172 of the inner wall 140), and then coupling the upper valve cage element to the outer and inner valve cage elements in any of the foregoing methods. In yet another such example, the integral body 116 can be formed by manufacturing a lower valve cage element (including, for example, a valve seat 108) and then coupling the lower valve cage element to an outer valve cage element and an inner valve cage element.

[0039] Return to reference Figure 1 and Figure 2The valve cage 104 also includes a valve cage inlet 190 and a valve cage outlet 194. In this example, the valve cage inlet 190 is formed in the integral body 116 at the second end 132, such that the valve cage inlet 190 extends along the longitudinal axis 124. However, in other examples, the valve cage inlet 190 may be formed at different locations and / or may extend along an axis different from the longitudinal axis 124 (e.g., along an axis transverse to the longitudinal axis 124). In this example, the valve cage outlet 194 is defined by a plurality of first feature passages 166, such that the valve cage outlet 194 is formed in the outer wall 136 of the integral body 116, located between the first end 128 and the second end 132 of the integral body 116. Therefore, the valve cage outlet 194 extends along an axis transverse to the longitudinal axis 124. However, in other examples, the valve cage outlet 194 may be formed at different locations and / or may extend along an axis different from the axis 196 (e.g., along the longitudinal axis 124).

[0040] Valve cage 104 also includes a plurality of cavities defined by an integral body 116 and extending between valve cage inlet 190 and valve cage outlet 194. In this example, valve cage 104 includes a first cavity 200 and a second cavity 204 defined by different portions of the integral body 116. More specifically, the first cavity 200 is defined by a second wall portion 176, a third wall portion 180, and a fourth wall portion 184, and the second cavity 204 is defined by a region between an outer wall 136 and an inner wall 140 located between the orifice 188 and the valve cage outlet 194. Thus, the first cavity 200 is immediately adjacent to and downstream of the valve cage inlet 190 within the integral body 116, and the second cavity 204 is downstream of the first cavity 200 and immediately adjacent to and upstream of the valve cage outlet 194 within the integral body 116. Furthermore, the second cavity 204 is in fluid communication with the slot inlet 187. Figure 2 As best shown, the first cavity 200 defines a first volume, and the second cavity 204 defines a second volume smaller than the first volume. However, in other examples, the valve cage 104 may include more or fewer cavities, the first cavity 200 and the second cavity 204 may be defined by different portions of the valve cage 104, and / or the dimensions of the first cavity 200 and the second cavity 204 may be designed to be different.

[0041] As described above, the internal channel 120 is entirely contained within the integral body 116. The internal channel 120 extends between the valve cage inlet 190 and the valve cage outlet 194. In this example, the internal channel 120 is defined or formed by a first cavity 120, an orifice 188, a plurality of first flow characteristic passages 186, and a second cavity 204, wherein the dimensions of each of these characteristics are designed to achieve the fluid pressure reduction required for a given application. However, in other examples, the internal channel 120 may be defined or formed by more, fewer, or different components.

[0042] Continue to refer to Figure 1 and Figure 2 The details of control element 112 will now be described. Control element 112, which may be made of one or more suitable materials (e.g., stainless steel, aluminum, and various alloys (e.g., nickel-chromium alloys)), typically includes an elongated plug 286 and a valve plug 290, the valve plug 290 being coupled to one end of the elongated plug 286. The elongated plug 286 and valve plug 290 may be integrally formed together, for example, using additive manufacturing techniques, or they may be formed separately and coupled together. In this example, the valve plug 290 is balanced, although not essential. In any case, when the valve plug 290 is movably disposed within the valve cage 104, the elongated plug 286 extends along a longitudinal axis 294 coaxial with the longitudinal axis 124. Simultaneously, the valve plug 290 has a body portion 296 slidably disposed within the bore 188 and engaging the inner wall 140 of the valve cage 104, and a sealing portion having a sealing surface 298 arranged to selectively engage the valve seat 108 of the valve cage 104 to open or seal the valve cage inlet 190 (and more generally, to open or seal the valve inner member 100, respectively). Finally, it will be understood that the control element 112 also includes one or more sealing elements coupled to the valve plug 290 to achieve a seal between the outer surface of the valve plug 290 and the inner surface of the inner wall 140 of the valve cage 104.

[0043] Figure 1 and Figure 2Also shown is a valve internal 100 (only a portion of it is shown for clarity) disposed in an example of a fluid flow control device 300 constructed according to the teachings of this disclosure. In short, the fluid flow control device 300 includes a valve body 304 and a valve cover 308 coupled to the valve body 304, wherein an elongated plug 286 is disposed in the valve body 304 and the valve cover 308. The valve body 304 defines an inlet 316, an outlet 320, and a fluid flow passage 324 included between the inlet 316 and the outlet 320. In this example, the inlet 316 extends along an inlet axis (which is perpendicular to axes 224, 294), and the outlet 320 extends along an outlet axis parallel to the inlet axis; however, in other examples, the outlet axis may not be parallel to (e.g., perpendicular to) the inlet axis. One end of the elongated plunger 286 is coupled to an actuator (not shown), such that the actuator (via the plunger 286) is operatively coupled to the valve plug 290 to control the position of the valve plug 290 within the valve cage 104, thereby controlling the flow of fluid through the internal passage 120, and more generally, controlling the fluid flow passage 324.

[0044] When the valve internals 100 are disposed in the fluid flow control device 300, the valve cage 104 engages different portions of the valve body 304 and the valve cover 308, and the valve plug 290 is movably disposed within the valve cage 104. More specifically, the flange 144 of the valve cage 104 engages both a first portion of the valve body 304 and a portion of the valve cover 308, and the shoulder 168 of the valve cage 104 engages a second portion of the valve body 304 that is closer to the valve cage inlet 190 than the first portion. Thus, the valve cage 104 is clamped in place by the valve body 304 and the valve cover 308. However, in other examples, different portions of the valve cage 104 may engage these or other portions of the valve body 304 and / or the valve cover 308. In any case, with the valve cage 104 disposed in this manner, the basic portion of the valve cage 104 is disposed within the fluid flow passage 324, thereby providing sufficient volume for fluid expansion (and decompression).

[0045] When the fluid flow control device 300 is in operation (in the case where the valve internals 100 are installed in the fluid flow control device 300), the valve plug 290 can be in the fully closed position (e.g., Figure 1 (as shown) and fully open position (as shown) Figure 2 The valve plug 290 moves between (as shown) the internal passage 120 and, more specifically, the fluid flow passage 324 (via valve stem 286 and an actuator coupled thereto) to close or open the internal passage 120, and more specifically the fluid flow passage 324. When valve plug 290 is in... Figure 1In the fully closed position shown, the sealing surface 298 of the valve plug 290 seals against the valve seat 108 of the valve cage 104, thereby closing the valve cage inlet 190. This prevents fluid from flowing through the internal passage 120, thus preventing fluid from flowing from the inlet 316 to the outlet 320 via the fluid flow passage 324. However, when the valve plug 290 is moved from this fully closed position... Figure 2 In the fully open position, as shown, valve plug 290 moves toward the first end 128 of the integral body 116. This causes body portion 296 to move upward along the inner wall 140 (when in...). Figure 2 During observation, the valve moves, thereby exposing some (and eventually all) of the multiple second flow characteristic passages 186, and causing the sealing surface 298 to move away from the valve seat 108, thereby opening the valve cage inlet 190. This, in turn, allows fluid to flow through the internal passage 120, allowing fluid to flow from the inlet 316 to the outlet 320 via the fluid flow passage 324.

[0046] When valve plug 290 is in its fully open position, fluid that has entered valve body 304 via inlet 316 flows into valve cage 104 via valve cage inlet 190. In many cases, although not always, the fluid entering valve cage inlet 190 will have a high pressure. The fluid passes through valve cage inlet 190 and through valve seat 108 without experiencing any significant pressure drop (thus protecting valve seat 108). The fluid is then forced into first chamber 200, which allows the fluid to expand and thus reduce the fluid pressure (i.e., first pressure reduction stage). The fluid is then forced into orifice 188, which forces the fluid to flow radially inward, away from the outer wall 136 of valve cage 104, thus further reducing the fluid pressure (i.e., second pressure reduction stage). The fluid is then forced through multiple second flow characteristic passages 186, thus further reducing the fluid pressure (i.e., third pressure reduction stage). After passing through multiple second flow characteristic passages 186, the fluid is forced into second chamber 204, which allows the fluid to expand again, thus further reducing the fluid pressure (i.e., fourth pressure reduction stage). At this point, the fluid is forced through multiple first flow characteristic passages 166 (i.e., valve cage outlet 194), thereby further reducing the fluid pressure (i.e., fifth pressure reduction stage) so that the fluid leaves the valve cage 104 and flows to the outlet 320 of the valve body 304. In this way, the fluid leaving the valve cage 104 has a lower pressure than the fluid entering the valve cage 104.

[0047] Finally, although in this example the valve internal 100 is an upward-flowing valve internal (because the fluid flows axially upward through the internal passage 120), in other examples, the valve internal 100 can be a downward-flowing valve internal (where the fluid will flow axially downward through the internal passage 120). In one such example, the valve internal 100 can be configured such that the valve cage inlet 190 is at or near the first end 128, and the valve cage outlet 194 is at or near the second end 132. Additionally, the valve seat 108 can be positioned at other locations within the valve cage 104, in which case the sealing surface 298 of the valve plug 290 can be moved to selectively seal against a repositioned valve seat 108.

[0048] This document describes preferred aspects of the invention, including the best modes known to the inventors for carrying out the invention. Although many examples are shown and described herein, it will be readily understood by those skilled in the art that the details of each aspect are not mutually exclusive. Rather, those skilled in the art, upon reading the teachings herein, should be able to combine one or more features of one aspect with one or more features of the remaining aspects. Furthermore, it should be understood that the aspects shown are merely exemplary and should not be construed as limiting the scope of the invention. Unless otherwise indicated herein or clearly contradicted by the context, all methods described herein can be performed in any suitable order. The use of any and all examples or exemplary language (e.g., “such as”) provided herein is intended only to better illustrate one or more aspects of the invention and does not constitute a limitation on the scope of the invention. No language in the specification should be construed as indicating that any unclaimed element is essential for carrying out the invention.

Claims

1. A valve internal for a fluid flow control device, the valve internal comprising: A valve cage body having a first end and a second end opposite to the first end, the valve cage body being defined by an outer valve cage wall and an inner valve cage wall coupled to the outer valve cage wall, the outer valve cage wall being radially spaced outward from the inner valve cage wall; The fluid decompression section includes: Multiple first flow characteristic passages are formed in the outer valve cage wall; and Multiple second flow characteristic passages are formed in the inner valve cage wall; and A pressure-reducing chamber, defined between the outer valve cage wall and the inner valve cage wall, such that the pressure-reducing chamber is fluidly connected to each of the plurality of first flow characteristic passages and fluidly connected to each of the plurality of second flow characteristic passages; and A valve seat, which is carried by the valve cage body, is located downstream of but adjacent to the second end of the valve cage body, such that the valve seat is isolated from the fluid depressurization section.

2. The valve internals according to claim 1, wherein, The valve cage body extends along the valve cage axis between the first end and the second end, and each of the plurality of first flow characteristic passages extends vertically along a first axis parallel to the valve cage axis.

3. The valve internals according to claim 2, wherein, Each of the plurality of second flow characteristic paths extends vertically along a second axis parallel to the valve cage axis and the first axis.

4. The valve internals according to claim 1, wherein, The plurality of first flow characteristic paths are spaced apart from and surround the plurality of second flow characteristic paths.

5. The valve internals according to claim 1, wherein, The valve cage body is at least partially made of corrosion-resistant material.

6. The valve internals according to claim 5, wherein, The inner valve cage wall is made of corrosion-resistant material.

7. The valve internals according to claim 1, wherein, The valve cage body is defined by an inner valve cage element and an outer valve cage element coupled to the inner valve cage element, the inner valve cage element including the inner valve cage wall, and the outer valve cage element including the outer valve cage wall.

8. The valve internals according to claim 7, further comprising an upper valve cage element coupled to the inner valve cage element and the outer valve cage element, wherein, The upper valve cage element is made of metal.

9. A fluid flow control device, comprising: A valve body, comprising a valve body inlet, a valve body outlet, and a channel extending between the valve body inlet and the valve body outlet; as well as A valve internal component, at least partially disposed within the passage of the valve body, the valve internal component comprising: A valve cage body is defined by an outer valve cage wall and an inner valve cage wall coupled to the outer valve cage wall, the outer valve cage wall being radially spaced outward from the inner valve cage wall, the valve cage body including a first end, a second end opposite to the first end, and a shoulder, the shoulder being configured to engage a portion of the valve body, wherein the shoulder is disposed between the first end and the second end. The valve seat is supported by the valve cage body at a position upstream of the shoulder; The valve seat is downstream of but adjacent to the second end of the valve cage body. Multiple first flow characteristic passages are formed in the outer valve cage wall; and Multiple second flow characteristic passages are formed in the inner valve cage wall. The valve cage body is at least partially made of corrosion-resistant material, and the shoulder is located entirely on the radially outer side of the valve seat.

10. The fluid flow control device according to claim 9, further comprising: A valve plug, including a support surface movably disposed within the valve cage body relative to the valve seat to control fluid flow through the passage of the valve body.

11. The fluid flow control device according to claim 10, further comprising a valve cover coupled to the valve body, wherein, The valve cover has a portion that directly engages with the upper valve cage portion of the valve cage body.

12. A method for manufacturing valve internals for a fluid flow control device, the method comprising: The outer valve cage element is generated using additive manufacturing technology, and the outer valve cage element includes a plurality of first flow characteristic passages; The additive manufacturing technology is used to produce an inner valve cage element, wherein the inner valve cage element is formed of a corrosion-resistant material and includes a plurality of second flow characteristic passages; and The outer valve cage element is coupled to the inner valve cage element to form a valve cage body, the valve cage body having an outer wall defined by the outer valve cage element and an inner wall defined by the inner valve cage element, and A pressure-reducing chamber is defined between the outer valve cage wall and the inner valve cage wall, such that the pressure-reducing chamber is fluidly connected to each of the plurality of first flow characteristic passages and fluidly connected to each of the plurality of second flow characteristic passages; Each of the plurality of first flow characteristic paths and each of the plurality of second flow characteristic paths includes a conical groove, the conical groove converging from the groove inlet to the middle groove portion and diverging from the middle groove portion to the groove outlet. The plurality of second flow characteristic pathways are the same as the plurality of first flow characteristic pathways.

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