JP2012067744A - Steam turbine valve having integral pressure chamber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam turbine valve (10) having an integral pressure chamber (18).SOLUTION: In one aspect of the invention, the valve for supplying steam (10) includes a valve body (12); and a pressure chamber (18) substantially contained within a wall (14) of the valve body (12), the pressure chamber (18) having an inlet (24) for receiving a pressurized fluid.

Description

  The subject matter disclosed herein relates to steam turbine valves. More specifically, the subject matter disclosed herein relates to a steam turbine valve with an integral pressure chamber formed, for example, by a casting method or other fabrication method.

  During operation of the steam turbine system, various valves supply steam to the operating parts of the system so that they can perform mechanical work. However, the flow of steam through the valves causes pressure and heat related stresses on the valves to shorten their useful life and / or cause damage. In addition, the operating conditions of steam turbine systems tend to be high temperature and high pressure applications with faster start-up and load ramp rates, which can cause significant stress on the valves in those systems.

US Pat. No. 6,655,409

  A steam turbine valve having an integral pressure chamber is disclosed. In one embodiment, a system for supplying steam is disclosed, the valve system including a valve body and a pressure chamber substantially enclosed within a wall of the valve body, the pressure chamber containing pressurized fluid. Has an entrance to receive.

  A first aspect of the invention includes a valve system, the valve system including a valve body and a pressure chamber substantially enclosed within a wall of the valve body, the pressure chamber receiving pressurized fluid. Has an entrance.

  A second aspect of the present invention includes a steam turbine system, the steam turbine system including a steam turbine section and a valve system for supplying steam to the steam turbine section, the valve system including a valve body and a valve body. A pressure chamber substantially enclosed within the wall of the pressure chamber, the pressure chamber having an inlet for receiving pressurized fluid.

  A third aspect of the present invention includes a valve for supplying steam, the valve including a valve body and a pressure chamber substantially enclosed within a wall of the valve body, the pressure chamber comprising a pressurized fluid Having an entrance to receive.

  These and other features of the present invention will be more readily understood from the following detailed description of various aspects of the invention, taken in conjunction with the accompanying drawings which illustrate various embodiments of the invention. .

1 is a schematic cross-sectional view of a valve system according to an embodiment of the present invention. 1 is a schematic diagram of a steam turbine system including a valve system according to an embodiment. FIG.

  It should be noted that the drawings of the present invention are not to scale. The drawings are only intended to illustrate exemplary embodiments of the invention and therefore should not be considered as limiting the scope of the disclosure. In the drawings, like reference numbers represent like elements between the drawings.

  As described above, aspects of the present invention provide a steam turbine valve having an integral pressure chamber. Specifically, aspects of the present invention provide a steam turbine valve having an integral casting or fabrication pressure chamber. The integrated pressure chamber is formed with an inlet and an outlet through which steam can flow. Steam can be supplied to the chamber as a) a preheating agent that reduces thermally induced transient stresses, and / or b) a pressurizing agent during steady state operation that reduces long-term film stress and peak stress across the load bearing valve wall.

  Conventional solutions for reducing stress in steam turbine valves use double shell valve casings, but these solutions often require increased casing complexity and cost. In contrast to these conventional solutions, aspects of the present invention provide an integral pressure chamber with a single casing design. Compared to conventional solutions, the teachings of the embodiments of the present invention make the following points: a) The manufacturing cost of the single casing valve described herein, in particular, is due to the reduction in the materials required and the double shell valve casing. And b) the integrated chamber allows preheating of the valve, thus realizing that the start-up time can be reduced when compared to a conventional single casing valve. it can.

  Turning to FIG. 1, a steam turbine valve system (or valve system) 10 according to an embodiment of the invention is shown. As shown, the valve system 10 can include a valve body 12 having a valve wall 14. The valve body 12 can further include a valve head 16 that is used to control the amount of steam flowing through the working portion of the valve body 12 as is known in the art. be able to. Other conventional components in a steam turbine valve include a valve stem 15, a control valve head 17, a valve seat 19, a balance chamber 21, a strainer 23, and a control valve bush 25. These components are not described herein for the sake of brevity, but when considering the valve system 10 aspect, these components are substantially the same as in conventional steam turbine valves. It should be understood that it can operate.

  In contrast to conventional steam turbine valves, the valve system 10 can include a valve wall 14 having a pressure chamber (or chamber) 18 substantially enclosed therein. That is, the pressure chamber 18 may be formed in the valve wall 14 such that the pressure chamber 18 is substantially enclosed between the outer surface 20 of the valve wall 14 and the inner surface 22 of the valve wall 14. it can. The pressure chamber 18 may have an inlet 24 that receives pressurized fluid (eg, steam) and an outlet 26 that discharges the pressurized fluid. Inlet 24 may include or be fluidly attached to inlet port 28, and outlet 26 may include or be fluidly attached to outlet port 30. Inlet port 28 and outlet port 30 may facilitate attachment and / or removal of one or more conduits from inlet 24 and outlet 26, respectively. Further, the inlet port 28 and outlet port 30 can effectively seal the inlet 24 and outlet 26, respectively, as desired.

  As illustrated and described herein, the pressure chamber 18 can be integral with the valve wall 14. That is, in one embodiment, the pressure chamber 18 can be cast integrally with the single wall (valve wall 14) design shown. For example, a mold (eg, comprising ceramic) can be formed with a coring substantially similar to the pressure chamber 18. After the valve wall material (eg, a metal such as steel, iron, etc.) has been cast and solidified, the coring can be removed to form the valve wall 14 with the pressure chamber 18. In another embodiment, portions of the valve wall 14 can be welded or otherwise abutted (eg, by forging, baking, etc.) to form the pressure chamber 18 therein.

  With continued reference to FIG. 1, the valve head 16 may include a valve head outlet 32 that includes or can be fluidly attached to the valve head outlet port 34. The valve head discharge port 34 can be fluidly coupled to a leak-off conduit 36 that allows pressurized leak-off fluid (eg, steam) to flow out of the valve head 16 and reduce the internal pressure in the valve wall 14. be able to. The leak-off conduit 36 can have one or more portions (eg, 36A, 36B), and one or more of those portions (eg, 36B) can pass pressurized fluid (eg, steam) from the valve head 16 ( In particular, it can be configured to supply to the pressure chamber 18 (via the inlet 24 and inlet port 28) from the valve head discharge port 34.

  Also shown in FIG. 1 is a discharge conduit 38 fluidly connected to the outlet 26 (via the outlet port 30). The exhaust conduit 38 allows pressurized fluid flowing into the chamber 18 to flow out of the chamber 18 and flow downstream (eg, to an atmospheric outlet or reheater, not shown). The drain conduit 38 is shown as comprising a drain 40, which can allow condensate from the pressurized fluid to drain from the drain conduit 38 and avoid accumulation in the drain conduit 38. The exhaust conduit 38 and the leak-off conduit 36 can each include one or more shut-off valves 42. In one embodiment, the exhaust conduit 38 and the leak-off conduit 36 can be fluidly coupled at a location downstream of the shutoff valve 42.

  In another embodiment, an external pressurized fluid source 44 (outside of the valve system 10) is connected to the inlet 24 of the pressurized chamber (pressure chamber) 18 (eg, a leak-off conduit 36B, as shown in phantom in FIG. Can be fluidly coupled (via a supply conduit 46 fluidly coupled to). In one embodiment, the external pressurized fluid source 44 can include an auxiliary boiler, a heat recovery steam generator (HRSG), or another source of pressurized fluid. Although illustrated as having a leak-off conduit 36A, it should be understood that embodiments using an external pressurized fluid source 44 and a supply conduit 46 are those that do not include a leak-off conduit. That is, the valve leak-off steam may not be used as a fluid source to the pressurized chamber 18 in some embodiments. In other embodiments, both the leak-off steam and the external pressurized fluid can be utilized to supply the pressurized chamber 18 (eg, as a mixed fluid).

  In practice, the valve system 10 can reduce the pressure imbalance across the valve wall 14. That is, the pressurized fluid provides a positive pressure inside the valve body 12 (eg, over the inner surface 22), so that the pressure chamber 18 faces the positive pressure applied to the inner surface from the inside of the valve body 12 in the valve wall 14. A positive pressure can be applied. This counter pressure serves to reduce the mechanical stress experienced by the valve wall 14, thereby providing advantages over conventional valve systems. For example, when starting a steam turbine system with valve system 10, pressure chamber 18 is utilized to utilize preheated steam (eg, as a leak-off from valve head outlet 32 or from an external pressurized fluid source) through valve wall 14. ) Can be supplied. In this case, preheated steam can flow through the pressure chamber 18 and heat the valve wall 14. As the valve wall 14 is warmed by the flow of steam through the pressure chamber 18, the internal temperature of the valve wall 14 increases. This allows the inner surface 22 (and outer surface 20) of the valve wall 14 to be sufficiently warmed before hotter and higher pressure steam begins to flow through the valve body 12 and over the inner surface 22.

  If the inner surface 22 is sufficiently pre-warmed, heat-induced transient stresses caused by high pressure and high temperature steam flowing through the valve body 12 can be reduced. In some cases, this pre-warming action can increase the operating life of the valve body 12. In addition, by prewarming the valve wall 14, higher temperature and higher pressure steam can be forced to flow through the valve body 12 more rapidly than in conventional valves, so that the steam turbine provided with the valve system 10. It can allow for faster startup of the system.

  In contrast to conventional single shell valve casings, the valve system 10, particularly the pressure chamber 18, introduces positive pressure into the valve wall 14 to counter internal fluid pressure applied to the inner surface 22. Thereby, in particular, the operating life of the valve body 12 can be extended. The valve body 12 shown and described with reference to FIG. 1 performs one or more additional steps associated with forming a pressure chamber 18 in the valve wall 14 (eg, by casting or other fabrication methods). Although required, the valve body 12 can be formed with less material and complexity than conventional double shell valve casings. Accordingly, the valve system 10 can improve the performance characteristics of the valve body 12 compared to a conventional single shell valve casing, while reducing costs compared to a conventional double shell valve casing.

  Although FIG. 1 illustrates a valve system according to an embodiment, it should be understood that other configurations of the valve system are also possible. For example, the pressure chamber 18 can be formed in any section of the valve wall 14 and a plurality of pressure chambers 18 can be formed in one or more sections of the valve wall 14. When a plurality of pressure chambers 18 are formed in the valve wall 14, one or more of the pressure chambers 18 are supplied by valve leak-off steam (eg, from the valve head 16) or an external pressurized fluid source 44. be able to. Further, when a plurality of pressure chambers 18 are formed in the valve wall 14, at least one of the pressure chambers 18 can be supplied by a source different from one or more other pressure chambers 18.

  Turning to FIG. 2, a steam turbine system 110 according to an embodiment is shown. As shown, the steam turbine system 110 supplies steam to a plurality of steam turbine sections, such as, for example, a high pressure / intermediate pressure (HP / IP) section 130 and a double flow low pressure steam turbine section 120, and the steam turbine sections 120, 130. One or more valve systems 10 can be included. It should be understood that the low pressure section 120 and the HP / IP section 130 can be any conventional HP / IP steam turbine section or low pressure section. The valve system 10 may supply steam to the steam turbine sections 120, 130, for example, from an external pressurized fluid source 44 (such as an auxiliary boiler or HRSG). In addition, the valve system 10 passes from the HP / IP steam turbine 130 to the external pressurized fluid source 44 (e.g., indicated by a conduit phantom when the external pressurized fluid source 44 is HRSG), to the condenser 140, Alternatively, steam can be supplied to the atmosphere (not shown). In any case, the valve system 10 may be used, among other things, to improve the start-up time of the steam turbine system 110 and improve the reliability and operating life of one or more valves using the teachings described herein. The steam turbine system 110 can be operated more efficiently. Although the steam turbine system 110 is illustrated as comprising one or more valve systems 10 coupled to conduits for the low pressure section 120 and the HP / IP section 130, in one embodiment, the valve system 10 is HP / IP. It should be understood that it can be used primarily in conduits for section 130 (and particularly high pressure sections). Further, it should be understood that conventional additional conduits and components may be omitted for clarity.

  The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, an expression without a numeral is intended to also include a plurality of forms unless the context clearly indicates otherwise. Further, as used herein, the terms “include” and / or “include” specify the presence of the described feature, number, step, operation, element, and / or component, but one or more It should be understood that this does not exclude the presence or addition of other features, times, steps, operations, elements, components and / or groups thereof.

  This written description uses examples, including the best mode, to disclose the invention and to enable any person skilled in the art to make and use any device or system and perform any embedded method. Implementation can also be performed. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other embodiments may include structural elements that do not differ from the language of the claims or that they contain equivalent structural elements that have substantive differences from the language of the claims. Is intended to fall within the scope of the appended claims.

DESCRIPTION OF SYMBOLS 10 Valve system 12 Valve body 14 Valve wall 15 Valve stem 16 Valve head 17 Control valve head 18 Pressure chamber 19 Valve seat 20 Outer surface 21 Balance chamber 22 Inner surface 23 Sterena 24 Inlet 25 Control valve bush 26 Outlet 28 Inlet port 30 Outlet Port 32 Valve head outlet 34 Valve head outlet port 36 Leak-off conduit 36A First portion 36B Second portion 38 Discharge conduit 40 Drain 42 Shut-off valve 44 External pressurized fluid source 46 Supply conduit 110 Steam turbine system 120 Double flow low pressure steam turbine Section 130 High / Medium Pressure Section 140 Condenser

Claims (10)

A valve system (10) for supplying steam,
A valve body (12);
A valve system (18) comprising a pressure chamber (18) substantially enclosed within a wall (14) of the valve body (12), the pressure chamber (18) having an inlet (24) for receiving pressurized fluid. 10).   The valve system (10) of claim 1, wherein the pressure chamber (18) further comprises an outlet (26) for discharging the pressurized fluid.   The valve system (10) of claim 2, further comprising a valve head (16) having a valve head outlet (32).   A leak-off conduit (36) fluidly connected to the valve head outlet (32) and inlet (24) to supply the pressurized fluid from the valve head (16) to the pressure chamber (18). The valve system (10) of claim 3, further comprising a configured leak-off conduit (36).   The valve system (10) of claim 4, wherein the pressurized fluid is leak-off steam.   The valve system (10) of claim 4, further comprising a discharge conduit (38) fluidly connected to the outlet (26), the drain conduit (38) comprising a drain (40).   The leak-off conduit (36) and the exhaust conduit (38) each include a shut-off valve (42), and the leak-off conduit (36) is connected to the exhaust conduit (38) downstream of each of the shut-off valves (42). The valve system (10) of claim 6, wherein the valve system (10) is fluidly coupled.   The valve system (10) of any preceding claim, further comprising an external pressurized fluid source (44) fluidly coupled to the inlet (24).
A steam turbine section (120, 130);
A steam turbine system (110) comprising a steam system (10) for supplying steam to the steam turbine section (120, 130), wherein the valve system (10) comprises:
A valve body (12);
A pressure chamber (18) substantially enclosed within a wall (14) of the valve body (12), the pressure chamber (18) having an inlet (24) for receiving pressurized fluid; Steam turbine system (110). A valve (10) for supplying steam,
A valve body (12);
A valve (10) comprising a pressure chamber (18) substantially enclosed within a wall (14) of said valve body (12), said pressure chamber (18) having an inlet (24) for receiving pressurized fluid. ).