Steam turbine engine valve with one valve element and a sealing arrangement

Abstract

Steam turbine engine valve comprising: a valve body (40) having an inlet section (42), an outlet section (44) and an inner section (52), wherein the inner section (52) includes an inner wall (54); a valve member (58) being slidably arranged within the inner section (52) of the valve body (40), wherein the valve member (58) includes an outer surface (65); a sealing element (70) being mounted on and extending around the outer surface (65) of the valve member (58), wherein the sealing element (70) is spaced from the inner wall (54) by a gap (84);and a sealing arrangement (100) mounted on the inner wall (54), wherein the sealing arrangement (100) spans the gap (84) and is configured and arranged to be in contact with the sealing element (70) of the valve member (58), wherein the sealing arrangement (100) comprises a mechanical seal (104), a first seal holder (116) and a second seal holder (118), wherein the mechanical seal (104) is arranged between the first and the second seal holder (116, 118) and each of the first and the second seal holder (116, 118) extends into and is encompassed by the inner wall (54).

Description

BACKGROUND OF THE INVENTIONThe subject matter disclosed herein relates to the field of steam turbomachines, and more particularly to a steam turbomachine valve having a valve member and a seal assembly.Steam turbomachine systems generally include a plurality of turbine sections, each of which extracts work from a steam flow. The plurality of turbine sections may include a high pressure (HP) steam turbine section, an intermediate pressure (IP) steam turbine section, and a low pressure (LP) steam turbine section. One or more valves control the flow of steam flowing from one of the turbine sections to other of the turbine sections and, in some cases, to a heat recovery steam generator (HRSG). Each of the one or more valves includes a valve body that holds a valve member. The position of the valve member is selectively controlled to prevent the passage of the vapor flow or to allow the vapor flow to pass through. The valve includes a seal between the valve member and the valve body. In most cases, the seal is provided and positioned on the valve member to prevent vapor flow from passing through a gap between the valve member and the valve body and to maintain a lower pressure upstream of the valve.US 2010 / 0 270 491 A1 discloses a valve comprising: a valve body having an inlet portion, an outlet portion and an inner portion, the inner portion including an inner wall; a valve member slidably disposed within the inner portion of the valve body and including an outer surface; a snap ring mounted to and extending around the outer surface of the valve member, the snap ring spaced from the inner wall by a gap; and a seal assembly mounted to the inner wall and spanning the gap. The seal assembly is configured and arranged to contact the snap ring of the valve member.US 2012 / 0 304 952 A1 discloses a sealing arrangement for bypass valves for turbochargers of internal combustion engines, which is made of a nickel-chromium-based superalloy, which in particular has a chromium content of more than 10%.BRIEF DESCRIPTION OF THE INVENTIONAccording to one aspect of the invention, a steam turbomachine valve includes a valve body having an inlet portion, an outlet portion, and an inner portion. The inner portion includes an inner wall. A valve member is slidably disposed within the inner portion of the valve body. The valve member includes an outer surface. A sealing element is mounted on and extends around the outer surface of the valve member. The sealing element is spaced from the inner wall by a gap. A sealing arrangement is mounted on the inner wall. The seal assembly spans the gap and is configured and arranged to contact the seal member of the valve member. The seal assembly includes a mechanical seal, a first seal mount, and a second seal mount, the mechanical seal being disposed between the first and second seal mounts. Each of the first and second seal brackets extends into the inner wall and is captured by the inner wall.The seal arrangement of the aforementioned steam turbomachine valve may include a mechanical seal having a plurality of sealing elements.The seal assembly of any of the aforementioned steam turbomachine valves may be formed from a nickel-chromium-based superalloy.The valve member of any of the aforementioned steam turbomachine valves may be formed from a high alloy stainless steel having a chromium content between about 10% and 16%, wherein the sealing member is formed from a nickel-chromium based superalloy.The valve member of any of the aforementioned steam turbomachine valves may include a first inner portion separated from a second inner portion by a wall having a first surface and an opposing second surface.Any steam turbomachine valve mentioned above may further include: at least one reinforcing member mounted on one of the first and second surfaces of the wall.The at least one reinforcement member of any of the aforementioned steam turbomachine valves may include a first reinforcement member mounted to the first surface of the wall and a second reinforcement member mounted to the second surface of the wall, each of the first and second reinforcement members being made of a nickel-chromium based superalloy.Any steam turbomachine valve mentioned above may further include: a valve stem operatively connected to the valve member via the at least one boost member.According to another aspect of the invention, a steam turbomachine includes a high pressure (HP) turbine section, an intermediate pressure (IP) turbine section operatively connected to the HP turbine section, a low pressure (LP) turbine section operatively connected to at least one of the HP turbine section and the IP turbine section, and a steam valve fluidly connected to at least one of the HP turbine section, the IP turbine section, and the LP turbine section. The vapor valve includes a valve body having an inlet portion, an outlet portion, and an inner portion. The inner portion includes an inner wall. A valve member is slidably disposed within the inner portion of the valve body. The valve member includes an outer surface. A sealing element is mounted on and extends around the outer surface of the valve member. The sealing element is spaced from the inner wall by a gap. A seal assembly is mounted to the inner wall. The seal assembly spans the gap and is configured and arranged to contact the seal member of the valve member.The seal assembly of any of the aforementioned steam turbomachine may include a mechanical seal, a first seal mount, and a second seal mount, the mechanical seal disposed between the first and second seal mounts.Each of the first and second seals of any of the aforementioned steam turbomachines may extend into and be captured by the inner wall.The mechanical seal of any of the aforementioned steam turbomachine may include a plurality of sealing elements.The valve member of any of the aforementioned steam turbomachine may be made of a high alloy stainless steel having a chromium content between about 10% and 16%, and each of the sealing element and the plurality of sealing elements is made of a nickel-chromium based superalloy.The valve member of any of the aforementioned steam turbomachine may include a first inner portion separated from a second inner portion by a wall having a first surface and an opposing second surface.Any of the aforementioned steam turbomachine may further include: a valve stem operatively connected to the valve member; and at least one reinforcing member mounted to one of the first and second surfaces of the wall, the valve stem operatively connected to the at least one reinforcing member.The at least one reinforcing element of any of the aforementioned steam turbomachine may include a first reinforcing element mounted to the first surface of the wall and a second reinforcing element mounted to the second surface of the wall, each of the first and second reinforcing elements being made of a nickel-chromium-based superalloy.In yet another aspect of the invention, a steam turbomachine system includes a high pressure (HP) turbine section, an intermediate pressure (IP) turbine section operatively connected to the HP turbine section, a low pressure (LP) turbine section operatively connected to at least one of the HP turbine section and the IP turbine section, either a heat recovery steam generator (HRSG) or a boiler operatively connected to each of the HP turbine section, the IP turbine section, and the LP turbine section, and a steam valve fluidly connected to at least one of the HP turbine section, the IP turbine section, and the LP turbine section. The vapor valve includes a valve body having an inlet portion, an outlet portion, and an inner portion. The inner portion includes an inner wall. A valve member is slidably disposed within the inner portion of the valve body. The valve member includes an outer surface. A sealing element is mounted on and extends around the outer surface of the valve member. The sealing element is spaced from the inner wall by a gap. A seal assembly is mounted to the inner wall. The seal assembly spans the gap and is configured and arranged to contact the seal member of the valve member.The valve member of any steam turbomachine system mentioned above may be made of a high alloy stainless steel having a chromium content between about 10% and 16%, and including a first inner portion separated from a second inner portion by a wall having a first surface and an opposing second surface, wherein at least one nickel-chromium-based superalloy reinforcement member is mounted to one of the first and second surfaces of the wall, and a valve stem is operatively connected to the at least one nickel-chromium-based superalloy reinforcement member.These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.BRIEF DESCRIPTION OF THE DRAWINGSThe subject matter considered to be the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: FIG. 1 is a schematic view of a steam turbomachine system including a steam turbomachine fluidly connected to a valve having a valve member and a seal assembly, according to an example embodiment; FIG. 2 is a partially cut away perspective view of the valve including the valve member and seal assembly of FIG. 1; FIG. 3 is a plan view of the seal assembly of FIG. 2; and FIG. 4 is a cross-sectional view of the valve member of FIG. 2.The detailed description explains embodiments of the invention together with advantages and features on the basis of an example with reference to the drawings.DETAILED DESCRIPTION OF THE INVENTIONA steam turbomachine system according to an example embodiment is generally indicated at 2 in FIG. 1. The steam turbomachine system 2 includes a high pressure (HP) turbine section 4 operatively connected to an intermediate pressure (IP) turbine section 6 and a low pressure (LP) turbine section 8. The HP turbine section 4, the IP turbine section 6, and the LP turbine section 8 are fluidly connected to a heat recovery steam generator (HRSG) 10. Alternatively, the HP turbine section 4, the IP turbine section 6, and the LP turbine section 8 may be fluidly connected to a boiler. It should be understood that HP turbine section 4, IP turbine section 6, and LP turbine section 8 may also be fluidly connected to a boiler (not shown). At this point, it should be understood that HP turbine section 4, IP turbine section 6, and LP turbine section 8, although shown mechanically linked by shaft 12, may also be separate mechanisms. The term "operatively connected" should be understood to include a mechanical and / or fluidic connection.The HP turbine section 4 receives steam through an HP turbine inlet 14 and passes steam to an HP section (not separately labeled) of the HRSG 10 via an HP outlet 16. The MD turbine section 6 is fluidly connected to an MD section (also not separately labeled) of the HRSG 10 via an MD inlet 17 and an MD outlet 18. The LP turbine section 8 is fluidly connected to an LP section (not separately labeled) of the HRSG 10 via an LP inlet 20 and an LP outlet 22. The LP turbine section 8 is also shown mechanically connected to a mechanical load 24, such as a generator, a pump, or the like.According to an exemplary embodiment, a steam valve 30 is fluidly connected to the MD inlet 17. Of course, it should be understood that additional valves (not illustrated) may be connected between the steam turbine engine system 2 and the HRSG 10 and / or a boiler. Further, a valve (not illustrated) may be provided at the HP inlet 14. As illustrated in FIG. 2, the steam valve 30 includes a valve body 40 that includes an inlet portion 42 fluidly connected to the HRSG 10 and an outlet portion 44 fluidly connected to the MD turbine portion 6. The valve body 40 further includes a first inner portion 46 having a first inner wall 48 surrounding a balance chamber 50. The balance chamber 50 may be made of a high alloy stainless steel having a chromium content between about 10% and 16%, such as type 410 stainless steel, type 416 stainless steel, COST E, COST B, and / or 12 chromium, and includes a second inner portion 52 having a second inner wall 54. The first valve member 58 may take the form of a control valve disc or a capture valve disc and is operatively connected to a first valve stem 60. The first valve stem 60 is connected to an actuator (not shown) disposed at an upper portion (not separately designated) of the steam valve 30.The first valve member 58 includes a first portion 61 having a first inner surface portion 62, an opposing second portion 63 having a second inner surface portion 64, and an outer surface 65. the first portion 61 is separated from the second portion 63 by a wall 67. The wall 67 is operatively connected to the first valve stem 60 in a manner which will be described in more detail below. The first valve member 58 is made of a high alloy stainless steel having a chromium content between about 10% and 16%, such as type 410 stainless steel, type 416 stainless steel, COST E, COST B, and / or 12 chromium, and is slidable between a first or closed position and a second or open position. In the closed position, the first valve member 58 rests on a valve seat 68 formed in the first inner portion 46 at the inlet portion 42. In the open position, steam is free to flow from the inlet portion 42 to the outlet portion 44. In the illustrated exemplary embodiment, the first valve member 58 includes a sealing member 70 mounted to the outer surface 65. The seal member 70 is mounted in a recess 72 (FIG. 3 ) formed in the outer surface 65 and extends around the first valve member 58. A retainer 73 retains the seal member 70 in the recess 72, and a split ring 74 secures the retainer 73 to the first valve member 58.A second valve member 75, which is illustrated as a check valve, is disposed within the first valve member 58 at the valve seat 68. The second valve member 75 is operatively connected to a second valve stem 76 and is selectively closed to interrupt all of the vapor flow through the vapor valve 30 in the event that the first valve member 58 does not fully close. The vapor valve 30 is further illustrated as including a screen 78 disposed around the compensation chamber 50. Steam inside the equilibrium chamber 50 is selectively evacuated to achieve a lower differential pressure between the upstream valve members 58 and 75 and a downstream outlet portion 44. Evacuation of steam allows the first and second valve members 58 and 75 to be displaced to the open position with less hydraulic forces on respective ones of the first and second valve shafts 60 and 76. To further facilitate opening and close a valve 30, a clearance or gap 84 (FIG. 3 ) is present between the outer surface 65 of the first valve member 58 and the second inner wall 54.The gap 84 is sized to aid operation of the first valve member 58 while limiting vapor leakage that could replace the evacuated vapor. It is desirable to maintain the gap 84 with a predetermined dimension over an operating life of the steam valve 30. Accordingly, as discussed in detail below, it is desirable to limit oxidation growth on interconnecting components to ensure unaffected operation of the vapor valve 30.Further according to an exemplary embodiment, the vapor valve 30 includes a nickel-chromium based seal assembly 100 mounted to the second inner wall 54. The nickel-chromium based seal assembly 100 spans the gap 84 to limit vapor leakage from the inlet portion 42 to the outlet portion 44. According to an aspect of the exemplary embodiment, the nickel-chromium based seal assembly 100 includes a mechanical seal 104 supported by the second inner wall 54. The mechanical seal 104 reduces a vapor leakage over the first valve member 58; the mechanical seal 104 can be formed from a plurality of sealing elements 106 in the form of circular rings. Each sealing element 106 is made of a nickel-chromium based superalloy such as Inoco® for example. At this point, it should be understood that each sealing element 106, although described herein as being annular, may be split to facilitate installation into the second inner wall 54. Alternatively, each sealing member 106 may be formed from a single or multiple sealing portions. Further, it should be understood that the seal assembly 100 may or may not include a one-piece annulus that may or may not include a gap to facilitate assembly. Further, each sealing element 106 includes a plurality of ribs 110 that connect to the sealing element 70.In the illustrated exemplary embodiment, the seal members 106 are disposed between a first seal mount 116 and a second seal mount 118. The first seal retainer 116 is captured within a first recess 120 formed in the second inner wall 54. Similarly, the second seal retainer 118 is captured in a second recess 122 formed in the second inner wall 54. The seal members 106 are disposed within a third recess 125 disposed between the first and second seal supports 116 and 118. The gripping of the first and second seal supports 116 and 118 within the recesses 120 and 122 reduces cracking problems associated with oxidation growth. That is, oxidation growth that may occur during operation has little effect on the clearances between the first and second seal brackets 120 and 122 and the seal members 106.The first seal retainer 116 is secured to the second inner wall 54 by a plurality of first mechanical fasteners 128. Similarly, the second seal retainer 118 is secured to the second inner wall 54 by a plurality of second mechanical fasteners 130. The first and second seal mounts 116 and 118 take the form of first and second split rings 134 and 136. A gap 140 is present between the first split ring 134 and the sealing elements 106. The gap 140 receives thermal and / or oxidation growth-related effects. Additionally, a gap 145 may be present between the seal assembly 100 and the balance chamber 50. The gap 145 may accommodate expansion of the seal assembly 100 within the recess 125. According to one aspect of the exemplary embodiment, the first and second split rings 134 and 136 are made of a nickel-chromium-based superalloy such as Inoco® for example. The use of nickel-chromium based superalloys allows the seal assembly 100 to accommodate thermal expansions of the compensation chamber 50 and the first valve member 58. By mounting the seal assembly 100 to the second inner wall 54, the compensation chamber 50 may be further formed from a high alloy stainless steel having a chromium content between about 10% and 16%, such as type 410 stainless steel, type 416 stainless steel, COST E, COST B, and / or 12 chromium. Forming the balance chamber 50 from a material other than the nickel-based superalloy significantly reduces production and maintenance costs of the steam valve 30. it should be understood that the nickel-chromium-based seal assembly 100 may also take the form of a non-sliding seal and / or a seal formed from a single seal element.It should be further understood that the use of the nickel-chromium based superalloy to produce the seal member 70 and seal assembly 100 allows the steam valve 30 to receive higher temperature steam flows. In particular, contact of a nickel-chromium-based superalloy with a nickel-chromium-based superalloy between the seal assembly 100 and the first valve member 58 promotes reduced oxidation growth between the seal member 70 and the mechanical seal 104 such that clearance distances between the outer surface 65 and the second inner wall 54 remain substantially stable at all operating temperatures and pressures, and further allows the steam valve 30 to accommodate steam temperatures of 1150°F (621.1°C) or more. In particular, the attachment of a nickel-chromium-based superalloy sealing member 70 to the outer surface 65 allows the first valve member 58 to be formed from a high alloy stainless steel having a chromium content of between about 10% and 16% while still absorbing the higher temperature vapor flows. The use of a high alloy stainless steel having a chromium content between about 10% and 16% to produce the first valve member 58 results in a significant cost and cycle time reduction of the steam valve 30 as compared to when the valve 30 is formed entirely from a nickel-chromium based superalloy or a Inoco® based material.Further according to the exemplary embodiment, wall 67 separating first portion 61 and second portion 63 of first valve member 58 includes a first surface 150 and an opposing second surface 152. The first surface 150 includes a first recessed portion 154, and the second surface 152 includes a second recessed portion 155. The wall 67 includes a first reinforcement member 156 mounted to the first surface 150 at the first recessed portion 154. The wall 67 further includes a second reinforcement member 158 mounted to the second surface 152 at the second recessed portion 155. In one aspect of the exemplary embodiment, each reinforcement member 156 and 158 is made of a nickel-chromium-based superalloy, such as Inoco® for example. A plurality of mechanical fasteners, two of which are illustrated at 164 and 166, connect the reinforcing member 156 to the second reinforcing member 158 via the wall 67. Further, according to the exemplary embodiment, the first valve stem 60 includes a recessed portion 170 that receives the first reinforcing member 156. In this arrangement, the first and second reinforcement members 156 and 158 provide support to the wall 67 such that the first valve member 58 may be made of a high alloy stainless steel having a chromium content between about 10% and 16%, such as type 410 stainless steel, type 416 stainless steel, COST E, COST B, and / or 12 chromium.Forming the reinforcement members 156 and 158 from a nickel-chromium-based superalloy such as Inoco® enables the valve 30 to operate at higher temperatures above, for example, 1150°F (621°C). Further, the formation of the reinforcement members 156 and 158 from a nickel-chromium-based superalloy, such as Inoco® enables the mechanical fasteners 166 to withstand higher shear loads during the opening of the first valve member 58 against full vapor pressure. Further, the use of a nickel-chromium based superalloy, such as Inoco® to produce the first reinforcing member 156 yields a material and, therefore, a coefficient of thermal expansion that mates with the reinforcing member 158 to reduce bending loads on the fasteners 164 and 166.Although the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention may be modified to incorporate any number of changes, modifications, substitutions or equivalent arrangements not heretofore described, but which are within the scope and spirit of the invention. In addition, it is to be understood that although various embodiments of the invention have been described, aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be considered as limited by the foregoing description, but is limited only by the scope of the appended claims.A steam turbomachine valve 30 includes a valve body 40 having an inlet portion 42, an outlet portion 44, and an inner portion 46. the inner portion 46 includes an inner wall 48. a valve member 58 is slidably disposed within the inner portion 46 of the valve body 40. The valve member 58 includes an outer surface 65. a sealing member 70 is mounted to and extends around the outer surface 65 of the valve member 58. The seal member 70 is spaced from the inner wall 48 by a gap 84. A seal assembly 100 is mounted to the inner wall 48. The seal assembly 100 spans the gap 84 and is configured and arranged to contact the seal member 70 of the valve member 58.Parts List:2 Steam turbomachine system 4 High pressure (HP) turbine section 6 Intermediate pressure (IP) turbine section 8 Low pressure (LP) turbine section 10 Waste heat steam generator (HRSG) 12 Shaft 14 HP inlet 16 HP outlet 17 IP inlet 18 IP outlet 20 LP inlet 21 LP outlet 24 Mechanical load 30 Steam valve 40 Valve body 42 Inlet section 44 Outlet section 46 First inner section 48 First inner wall 50 Compensation chamber 52 Second inner section 54 Second inner wall 58 First valve member 60 First valve stem 61 First section 62 First inner surface section 63 Opposite second section 64 Second inner surface section 65 Outer surface 67 Wall 68 Valve seat 70 Sealing element 72 Recess 73 Retaining element 74 Split ring 75 Second valve member 76 second valve stem 78 screen 84 gap 100 seal assembly 104 mechanical seal 106 multiple seal members 110 multiple ribs 116 first seal retainer 118 second seal retainer 120 first recess 122 second recess 125 third recess 128 multiple first mechanical fasteners 130 multiple second mechanical fasteners 134 first split ring 136 second split ring 140 gap 150 first surface 152 opposing second surface 154 first recessed portion 155 second recessed portion 156 first reinforcement member 158 second reinforcement member 164 multiple mechanical fasteners 166 multiple mechanical fasteners 170 recessed portion

Claims

A steam turbomachine valve comprising: a valve body (40) having an inlet portion (42), an outlet portion (44), and an inner portion (52), the inner portion (52) including an inner wall (54); a valve member (58) slidably disposed within the inner portion (52) of the valve body (40), the valve member (58) including an outer surface (65); a sealing member (70) mounted to and extending around the outer surface (65) of the valve member (58), the sealing member (70) being spaced from the inner wall (54) by a gap (84); and a seal assembly (100) mounted to the inner wall (54), the seal assembly (100) spanning the gap (84) and configured and arranged to contact the seal member (70) of the valve member (58), the seal assembly (100) comprising a mechanical seal (104), a first seal mount (116), and a second seal mount (118), the mechanical seal (104) being disposed between the first and second seal mounts (116, 118), and each of the first and second seal mounts (116, 118) extending into and being captured by the inner wall (54).The steam turbomachine valve of claim 1, wherein the mechanical seal (104) includes a plurality of sealing elements (106).The steam turbomachine valve of claim 1, wherein the seal assembly (100) is formed from a nickel-chromium-based superalloy; and / or wherein the valve member (58) is formed from a high alloy stainless steel having a chromium content between about 10% and 16%, and the seal member (70) is formed from a nickel-chromium-based superalloy.The steam turbomachine valve of claim 1, wherein the valve member (58) includes a first inner portion (61) separated from a second inner portion (63) by a wall (67) having a first surface (150) and an opposing second surface (152).The steam turbomachine valve of claim 4, further comprising: at least one reinforcing member (156, 158) mounted to one of the first and second surfaces (150, 152) of the wall (67).The steam turbomachine valve of claim 5, wherein the at least one reinforcement member (156, 158) includes a first reinforcement member (156) mounted to the first surface (150) of the wall (67) and a second reinforcement member (158) mounted to the second surface (152) of the wall (67), each of the first and second reinforcement members (156, 158) being formed from a nickel-chromium-based superalloy.The steam turbomachine valve of claim 6, further comprising: a valve stem (60) operatively connected to the valve member (58) via the at least one gain element (156, 158).A steam turbomachine comprising: a high pressure (HP) turbine section (4); an intermediate pressure (IP) turbine section (6) operatively connected to the HP turbine section (4); a low pressure (LP) turbine section (8) operatively connected to at least one of the HP turbine section (4) and the IP turbine section (6); and a steam valve (30) fluidly connected to at least one of the HP turbine section (4), the IP turbine section (6), and the LP turbine section (8), the steam valve (30) comprising: a valve body (40) including an inlet portion (42), an outlet portion (44), and an inner portion (52), the inner portion (52) including an inner wall (54); a valve member (58) slidably disposed within the inner portion (52) of the valve body (40), the valve member (58) including an outer surface (65); a sealing member (70) mounted to and extending around the outer surface (65) of the valve member (58), the sealing member (70) being spaced from the inner wall (54) by a gap (84); and a seal assembly (100) mounted to the inner wall (54), the seal assembly (100) spanning the gap (84) and configured and arranged to contact the seal member (70) of the valve member (58).A steam turbomachine system (2) comprising: a high pressure (HP) turbine section (4); an intermediate pressure (IP) turbine section (6) operatively connected to the HP turbine section (4); a low pressure (LP) turbine section (8) operatively connected to at least one of the HP turbine section (4) and the IP turbine section (6); either a waste heat steam generator (HRSG) (10) or a boiler operatively connected to each of the HP turbine section (4), the IP turbine section (6), and the LP turbine section (8); and a steam valve (30) fluidly connected to at least one of the HP turbine section (4), the IP turbine section (6), and the LP turbine section (8), the steam valve (30) comprising: a valve body (40) including an inlet portion (42), an outlet portion (44), and an inner portion (52), the inner portion (52) including an inner wall (54); a valve member (58) slidably disposed within the inner portion (52) of the valve body (40), the valve member (58) including an outer surface (65); a sealing member (70) mounted to and extending around the outer surface (65) of the valve member (58), the sealing member (70) being spaced from the inner wall (54) by a gap (84); and a seal assembly (100) mounted to the inner wall (54), the seal assembly (100) spanning the gap (84) and configured and arranged to contact the seal member (70) of the valve member (58).

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