Steam valve, steam turbine, and thermal power generation system

Abstract

To provide a steam valve which prevents drainage from flowing into the interior of an oil cylinder.SOLUTION: In order to achieve the above objective, a steam valve according to an embodiment includes: a connector connected to an end at the side different from one end of a valve rod in which a valve body is connected to the one end; a drain pan provided at the radial outer side relative to the connector with an axial direction of the valve rod set to a center, the drain pan including a partition wall facing an outer surface of the connector.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE Embodiments of the present invention relate to a steam valve, a steam turbine, and a thermal power generation system. [Background technology]

[0002] The rotation speed and output of a steam turbine used in a thermal power generation system are controlled by a steam valve drive device that controls the opening degree of various steam valves that adjust the flow rate of steam supplied to the steam turbine. For example, a main steam stop valve and a steam control valve are provided in a main steam system that supplies steam from a boiler to a high-pressure turbine, and the steam valve adjusts the flow rate and flow velocity of steam flowing into the steam turbine. Many of the various steam valves include a valve casing, a valve seat, a valve stem, a valve body, an oil cylinder, a drive piston, and a drive mechanism. When the drive mechanism receives a control signal from the steam valve drive device, the drive piston in the oil cylinder is moved via the drive mechanism, and the valve stem is also moved in conjunction with the drive piston. A valve body is provided at the other end of the valve stem, and the distance between the valve body and the valve seat changes as the valve stem moves, opening and closing the flow path inside the valve casing. When the valve body and the valve seat are separated from each other in an open state, steam guided from the steam system passes through the inside of the valve casing and is supplied to the steam turbine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-144193 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when steam passes through the inside of the valve casing, there is a possibility that the steam may leak out of the valve casing through a gap between the valve casing and the valve stem. When the temperature outside the valve casing is lower than the temperature inside the valve casing, such as when the thermal power generation system is started up, some of the steam leaking out of the valve casing may condense and become drain. In this case, in a bottom-driven steam valve in which the valve stem and oil cylinder are provided below the valve body, if the drain flows into the oil cylinder along the side of the valve stem, corrosion may occur inside the oil cylinder.

[0005] Therefore, the problem to be solved by the present invention is to provide a steam valve that prevents drain from flowing into the oil cylinder. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the steam valve of this embodiment is characterized by comprising a connector connected to an end of a valve rod having a valve body connected to one end thereof, the end being different from the one end, and a drain pan provided radially outward from the connector about the axial direction of the valve rod, the drain pan having a partition wall facing the outer surface of the connector. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic configuration diagram showing an example of a thermal power generation system 1 according to an embodiment of the present invention. [Diagram 2] FIG. 2A is a schematic diagram showing an example of a steam valve 100, and FIG. 2B is a cross-sectional view of a coupling mechanism 105 in a region P of FIG. [Diagram 3] 1A is a schematic diagram showing an example of a steam valve 200, FIG. 1B is a cross-sectional view of a coupling mechanism 205 in region Q of FIG. 1A, and FIG. 1C is an enlarged view of the coupling mechanism 205 in region R of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a steam valve according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the embodiment shown below is an example of an embodiment of the present invention, and is not intended to limit the scope of the invention. In addition, in order to more clearly show the difference between the embodiment of the present invention and the conventional one, a conventional steam valve will be described first as a comparative example, and then the steam valve of this embodiment will be described. In this case, the same parts or parts having similar functions will be given the same or similar symbols, and their description may be omitted. Also, the dimensional ratios in the drawings may differ from the actual ratios, and part of the configuration may be omitted from the drawings.

[0009] First, a thermal power generation system of this embodiment will be described with reference to FIG. 1. FIG. 1 is a schematic diagram showing an example of a thermal power generation system 1 of this embodiment. The thermal power generation system 1 of FIG. 1 includes a boiler 2, a main steam pipe 3, a main steam stop valve 4, a steam control valve 5, a high-pressure turbine 6, a low-temperature reheat pipe 7, a check valve 8, a high-temperature reheat pipe 9, a resteam stop valve 10, and an intercept valve 11. The thermal power generation system 1 also includes an intermediate-pressure turbine 12, a crossover pipe 13, a low-pressure turbine 14, a condenser 15, a condensate pipe 16, a feedwater pump 17, a high-pressure turbine bypass pipe 18, a high-pressure turbine bypass valve 19, a low-pressure turbine bypass pipe 20, and a low-pressure turbine bypass valve 21. The boiler 2 heats condensate and generates steam from the condensate. The main steam pipe 3 is a pipe that guides the steam generated by the boiler 2 to the high-pressure turbine 6. The main steam pipe 3 is provided with a main steam stop valve 4 and a steam control valve 5 , which adjust the flow rate of steam supplied from the main steam pipe 3 to the high-pressure turbine 6 .

[0010] The high-pressure turbine 6 converts the work received from the steam when the steam passes through into rotational energy by using rotor blades (not shown) connected to the rotating shaft, and transmits the rotational energy to a generator (not shown) via the rotating shaft. In this embodiment, in addition to the high-pressure turbine 6, an intermediate-pressure turbine 12 and a low-pressure turbine 14 (described later) are connected to a generator (not shown) in the axial direction of the rotating shaft via the rotating shaft. That is, the rotational energy generated in each of the high-pressure turbine 6, the intermediate-pressure turbine 12, and the low-pressure turbine 14 is transmitted to the generator (not shown) via the rotating shaft. The low-temperature reheat pipe 7 is a pipe that guides the steam that has done work in the high-pressure turbine 6 to the reheater of the boiler 2. The low-temperature reheat pipe 7 is provided with a check valve 8 for preventing the steam from flowing back. The high-temperature reheat pipe 9 is a pipe that guides the steam (reheated steam) reheated in the reheater of the boiler 2 to the intermediate-pressure turbine 12. The high-temperature reheat pipe 9 is provided with a resteam stop valve 10 and an intercept valve 11.

[0011] The intermediate-pressure turbine 12, like the high-pressure turbine 6, transmits rotational energy obtained from the steam as the steam passes through it using rotor blades (not shown) connected to the rotating shaft to a generator (not shown) via the rotating shaft. The crossover pipe 13 is a pipe that guides the steam that has done work in the intermediate-pressure turbine 12 to the low-pressure turbine 14.

[0012] Like the high-pressure turbine 6 and the intermediate-pressure turbine 12, the low-pressure turbine 14 transmits energy obtained from steam as the steam passes through it to a generator (not shown) via the rotating shaft, using moving blades (not shown) connected to the rotating shaft. The condenser 15 is provided downstream of the low-pressure turbine 14, and condenses the steam after it has done work in the low-pressure turbine 14, returning it to condensed water. The condensate pipe 16 is a pipe that connects the condenser 15 and the boiler 2, and guides the condensate to the boiler 2. A feedwater pump 17 is provided in the condensate pipe 16, and the condensate is guided to the boiler 2 after being pressurized by the feedwater pump 17.

[0013] The high-pressure turbine bypass pipe 18 is a pipe that connects the main steam pipe 3 upstream of the main steam stop valve 4 and the low-temperature reheat pipe 7 downstream of the check valve 8. The upstream side / downstream side here refers to the upstream side / downstream side with respect to the steam flow direction. The high-pressure turbine bypass pipe 18 is provided with a high-pressure turbine bypass valve 19. During normal operation, the high-pressure turbine bypass valve 19 is closed, but during startup, shutdown, and emergency shutdown of the thermal power generation system 1, the high-pressure turbine bypass valve 19 is opened to guide steam from the boiler 2 from the main steam pipe 3 to the low-temperature reheat pipe 7.

[0014] The low-pressure turbine bypass pipe 20 is a pipe that connects the high-temperature reheat pipe 9 upstream of the resteam stop valve 10 and the condenser 15. A low-pressure turbine bypass valve 21 is provided on the low-pressure turbine bypass pipe 20. During normal operation, the low-pressure turbine bypass valve 21 is closed, but during start-up, stop, and emergency stop of the thermal power generation system 1, the low-pressure turbine bypass valve 21 is opened to guide steam from the reheater of the boiler 2 from the high-temperature reheat pipe 9 to the condenser 15.

[0015] During normal operation of the thermal power generation system 1, steam generated by heating condensate in the boiler 2 passes through the main steam pipe 3 and is guided to the high-pressure turbine 6 via the main steam stop valve 4 and the steam control valve 5, and rotates moving blades (not shown) in the high-pressure turbine 6. The steam after doing work in the high-pressure turbine 6 passes through the low-temperature reheat pipe 7 and is guided to the reheater of the boiler 2 via the check valve 8, and is reheated in the reheater. The reheated steam (reheated steam) passes through the high-temperature reheat pipe 9 and is guided to the intermediate-pressure turbine 12 via the resteam stop valve 10 and the intercept valve 11, and rotates moving blades (not shown) in the intermediate-pressure turbine 12. The steam after doing work in the intermediate-pressure turbine 12 passes through the crossover pipe 13 and is guided to the low-pressure turbine 14, and rotates moving blades (not shown) in the low-pressure turbine 14. The steam after doing work in the low-pressure turbine 14 is condensed in the condenser 15 and returned to the condensate. The condensate is pressurized by a feed water pump 17, and then passes through a condensate pipe 16 and is guided to the boiler 2. The condensate guided to the boiler 2 is heated in the boiler 2 and is guided to the high-pressure turbine 6 again.

[0016] On the other hand, when the thermal power generation system 1 is started, stopped, or stopped in an emergency, the high-pressure turbine bypass valve 19 and the low-pressure turbine bypass valve 21 are opened. Then, the steam generated by heating the condensate in the boiler 2 is led from the main steam pipe 3 through the high-pressure turbine bypass pipe 18 to the condenser 15 via the low-temperature reheat pipe 7, the reheater of the boiler 2, the high-temperature reheat pipe 9, and the low-pressure turbine bypass pipe 20 in this order. The steam led to the condenser 15 is condensed in the condenser 15 and returned to the condensate. This condensate is pressurized by the feedwater pump 17, and then led again to the boiler 2 through the condenser pipe 16.

[0017] Next, in order to more clearly clarify the difference in configuration between the steam valve of this embodiment and a conventional steam valve, the configuration of the conventional steam valve will be described as a comparative example, and then the configuration of the steam valve according to this embodiment will be described.

[0018] (Comparative Example) A conventional steam valve 100 will be described with reference to Fig. 2. Fig. 2(a) is a schematic diagram showing an example of the steam valve 100, and Fig. 2(b) is a cross-sectional view of a coupling mechanism 105 in region P of Fig. 2(a). The steam valve 100 referred to here refers to a bottom-driven type among the main steam stop valve 4, steam control valve 5, resteam stop valve 10, etc., provided in various pipes of the thermal power generation system 1 described above. The bottom-driven type referred to here refers to a steam valve in which a valve body 104, which will be described later, is located above an oil cylinder 106 in the direction of gravity (simply referred to as the upper side in the following description).

[0019] First, a schematic diagram showing an example of a steam valve 100 will be described with reference to Fig. 2(a). The steam valve 100 in Fig. 2(a) includes a valve casing 101, a valve seat 102, a valve stem 103, a valve body 104, a coupling mechanism 105, an oil cylinder 106, and a drive mechanism 107.

[0020] The valve casing 101 defines a steam flow path and houses a part of the valve stem 102 and a valve body 103. The valve casing 101 has a steam inlet 101a and a steam outlet 101b. The steam inlet 101a is connected to the boiler 2 via a pipe (the main steam pipe 3 or the high-temperature reheat pipe 9), and the steam outlet 101b is connected to the steam turbine (the high-pressure turbine 6, the intermediate-pressure turbine 12, or the low-pressure turbine 14) via a pipe (the main steam pipe 3 or the high-temperature reheat pipe 9).

[0021] The valve seat 102 is provided on the inner wall of the valve casing 101 midway through the steam flow path inside the valve casing 101. Specifically, the valve seat 102 is provided on the inner wall of the valve casing 101 so as to abut against the valve disc 104 when the steam valve 100 is closed. "Abutting" here refers to a state in which the valve seat 102 contacts the valve disc 104 to such an extent that steam does not leak from the point where the valve seat 102 and the valve disc 104 contact each other.

[0022] The valve rod 103 is a valve stem of the steam valve 100 housed in the valve casing 101. One end (upper end) of the valve rod 103 is connected to the valve body 104, and the other end (lower end) is connected to a connector 108 of a coupling mechanism 105 described later.

[0023] The valve disc 104 is provided at one end of a valve stem 103 located in a steam flow path inside the valve casing 101, and is housed in the valve casing 101. The valve disc 104 moves in the axial direction of the valve stem 103 in conjunction with the sliding of the valve stem 103. Specifically, when the steam valve 100 is closed, the valve disc 104 and the valve seat 102 abut against each other, and when the valve stem 103 is slid upward from this state, the valve disc 104 moves away from the valve seat 102 in conjunction with the valve stem 103, opening the steam valve 100. In order to realize a state in which the steam valve 100 is closed (closed state) and an open state (open state), the valve stem 103 and the valve disc 104 move in conjunction with each other in the axial direction of the valve stem 103.

[0024] The coupling mechanism 105 is a mechanism provided between the valve stem 102 and the oil cylinder 106. The details of the coupling mechanism 105 will be described later.

[0025] The oil cylinder 106 is provided on the lower side in the direction of gravity of the valve casing 101 (hereinafter, simply referred to as the lower side). The oil cylinder 106 has a drive piston (not shown) therein. In the oil cylinder 106, when the drive piston (not shown) is driven by hydraulic pressure or the like, the drive force is transmitted to the valve rod 102 via the coupling mechanism 105, causing the valve rod 102 to slide.

[0026] The drive mechanism 107 is connected to the oil cylinder 106. When the drive mechanism 107 receives a control signal from a steam valve drive device (not shown), it drives a drive piston (not shown) inside the oil cylinder 106. For example, the drive mechanism 107 is a drive mechanism using a solenoid valve.

[0027] When the drive mechanism 107 receives a control signal from a steam valve drive device (not shown), a drive piston (not shown) in the oil cylinder 106 is driven via the drive mechanism, and the valve rod 103 slides in conjunction with the drive piston (not shown) via the coupling mechanism 105. The valve body 104 slides in the axial direction of the valve rod 103 in conjunction with the valve rod 103, changing the distance between the valve seat 102 and the valve body 104, and the steam flow path in the valve casing 101 is opened and closed. In the open state, steam flows from the steam inlet 101a to the steam outlet 101b, and this steam is supplied to the steam turbine (high pressure turbine 6, intermediate pressure turbine 12, or low pressure turbine 14). On the other hand, in the closed state, the valve body 104 abuts against the valve seat 102 and blocks the space between the steam inlet 101a and the steam outlet 101b, so that steam does not flow from the steam inlet 101a to the steam outlet 101b.

[0028] Next, the coupling mechanism 105 of the conventional steam valve 100 will be described with reference to Fig. 2(b). The coupling mechanism 105 of Fig. 2(b) includes a connector 108, a drain pan 109, a coupling 110, a piston rod 111, and a yoke 112.

[0029] The connector 108 has a recess 108a at one end (upper side) that connects with the valve rod 103, and a recess 108b on the outer surface of the other end (lower side). In other words, the connector 108 has the recess 108a on the upper side and the recess 108b on the lower side, and is connected to the valve rod 103 at the recess 108a, and is fitted into the coupling 110 at the recess 108b. In this way, the connector 108 connects the valve rod 103 and the coupling 110.

[0030] The drain pan 109 is composed of a tray 109a and a first drain hole 109b. The tray 109a is provided on the radial outside of the connector 108 centered on the axial direction of the valve rod 103 (hereinafter, simply referred to as the radial outside) and on the upper side of the coupling 110, and is fixed to the coupling 110 via a bolt 113. The first drain hole 109b is provided on the radial outside of the tray 109a, specifically, on the radial outside of a portion of the tray 109a that is connected to the coupling 110. Furthermore, the first drain hole 109b is shaped to extend from the radial outside of the tray 109a downward in the longitudinal direction, and is provided so that its lower end is located above a drain groove 112c described later, and allows the drainage received by the tray 109a to pass downward. When steam leaking from the gap between the valve casing 101 and the valve stem 103 to the outside of the valve casing 101 condenses into drainage, the drain pan 109 receives the drainage that falls down the valve stem 103 and the connector 108 in the receiving tray 109a and discharges the drainage from the first drain hole 109b.

[0031] Coupling 110 is provided above piston rod 111 and fixed to piston rod 111 via bolt 113. That is, bolt 113 fixes, from the top, tray 109a of drain pan 109, coupling 110, and piston rod 111. Coupling 110 is formed in a two-piece structure consisting of a C-shaped coupling member, and fits into recess 108b of connector 108.

[0032] The piston rod 111 is provided on the upper side of the oil cylinder 106 so as to be connected to a drive piston (not shown) inside the oil cylinder 106. The piston rod 111 is linked to the drive of the drive piston (not shown) inside the oil cylinder 106, and slides the valve shaft 103 via the coupling 110 and the connector 108.

[0033] The yoke 112 connects the valve casing 101 and the oil cylinder 106 and is provided to surround the coupling mechanism 105. The yoke 112 includes a connection piece 112a and a side wall 112b. The connection piece 112a is provided radially outward from the piston rod 111 and above the oil cylinder 106. The connection piece 112a is located below the first drain hole 109b and has a drain groove 112c that receives drainage dropping from the first drain hole 109b, and a second drain hole 112d that extends radially outward from the drain groove 112c. The side wall 112b is provided radially outward from the drain pan 109 and above the connection piece 112a, and connects the valve casing 101 and the oil cylinder 106. In the yoke 112, the drainage liquid that has fallen from the first drain hole 109b into the drain groove 112c is discharged to the outside from the second drain hole 112d.

[0034] When the drive mechanism 107 receives a control signal from a steam valve drive device (not shown), a drive piston (not shown) inside the oil cylinder 106 is driven via the drive mechanism. Then, the piston rod 111 is linked to the drive of the drive piston (not shown) and slides the valve stem 103 via the coupling 110 and the connector 108. As a result, the valve body 104 moves in the axial direction in linkage with the valve stem 103, opening and closing the steam flow path inside the valve casing 101.

[0035] Here, in order to clarify the problem of the comparative example, the flow of the drain leaking from the gap between the valve casing 101 and the valve rod 103 will be described. First, the flow A in FIG. 2(b) will be described. The drain leaking from the gap between the valve casing 101 and the valve rod 103 falls onto the upper surface of the coupling 110 along the outer surface of the valve rod 102 and the connector 108. The drain that falls onto the upper surface of the coupling 110 flows into the inside of the coupling 110 through the gap of the two-split structure of the coupling 110 and falls onto the upper surface of the piston rod 111. The drain that falls onto the upper surface of the piston rod 111 flows radially outward through the gap of the two-split structure of the coupling 110 and falls into the oil cylinder 106 along the outer surface of the piston rod 111. If the drain that falls inside the oil cylinder 106 remains, corrosion will occur inside the oil cylinder 106.

[0036] Next, flow B in Fig. 2(b) will be described. Drainage leaking from the gap between the valve casing 101 and the valve rod 103 falls into the tray 109a of the drain pan 109. The drainage that falls into the tray 109a of the drain pan 109 passes through the first drain hole 109b and falls into the drain groove 112c. The drainage that falls into the drain groove 112c is discharged to the outside from the second drain hole 112d. For this reason, corrosion is unlikely to occur inside the oil cylinder 106.

[0037] As described above, in the coupling mechanism 105 of the comparative example, as long as the drain flows like the flow A in FIG. 2(b), corrosion occurs inside the oil cylinder 106.

[0038] (Configuration of the steam valve according to this embodiment) The coupling mechanism 205 of the steam valve 200 according to this embodiment will be described with reference to Fig. 3. Fig. 3(a) is a schematic diagram showing an example of the steam valve 200, Fig. 3(b) is a cross-sectional view of the coupling mechanism 205 in region Q of Fig. 3(a), and Fig. 3(c) is an enlarged view of the coupling mechanism 205 in region R of Fig. 3(b). Note that hereinafter, the description will focus on the points that differ from the comparative example, and the other points will be assigned the same reference numerals as those in the comparative example and will not be described again.

[0039] The coupling mechanism 205 of FIG. 3( b ) includes a connector 208 , a drain pan 209 , a coupling 110 , a piston rod 111 , and a yoke 112 .

[0040] 3(c), the connector 208 includes a first portion 208a, a second portion 208b, and a third portion 208c. The first portion 208, the second portion 208b, and the third portion 208 are preferably provided such that the axial direction of the valve rod 103 is the central axis.

[0041] The first portion 208a is a portion that constitutes the upper side of the connector 208, and is provided with a recess 108a that is a connection point with the valve rod 103. In addition, a drain cutout 208d, which will be described later, is provided at the lower end of the first portion 208a.

[0042] The second portion 208b is a portion located below the first portion 208a, and is formed with an outer diameter smaller than the outer diameter of the first portion 208a in the radial direction.

[0043] The third portion 208c is a portion located below the second portion 208b, and is provided with a recess 108b that is a fitting portion with the coupling 110.

[0044] The drain cutter 208d is provided at the lower end of the first portion 208a. Specifically, the drain cutter 208d is provided at the end of the first portion 208a that is not connected to the second portion 208b among the boundary between the first portion 208a and the second portion 208b. For example, the drain cutter 208d is provided in a shape perpendicular to the central axis and tapered upward toward the central axis. At the radially outer tip of the drain cutter 208d, a tip portion 208e is provided so that the drain that has flowed down the side surface of the first portion 208a is cut off. For example, the tip portion 208e is provided as a corner portion having an angle such as a right angle or an acute angle (a shape cut off in this embodiment). In addition, in the drain cutter 208d, a processed surface 208f is provided in a portion radially inward of the cut-off tip portion 208e so as to prevent the drain that has not been cut off at the tip portion 208e from entering the inside of the drain cutter 208d from the outside in the radial direction. For example, the processed surface 208f is provided with a shape such as a curved or concave shape on the upper side (a shape machined on the upper side in this embodiment).

[0045] The drain pan 209 includes a tray 109a, a first drain hole 109b, and a partition wall 209a. The tray 109a is provided radially outside the second portion 208b of the connector 208 and above the coupling 110, and is fixed to the coupling 110 via a bolt 113. The first drain hole 109b is provided radially outside the tray 109a, specifically, radially outside the portion of the tray 109a that is connected to the coupling 110. Furthermore, the first drain hole 109b is provided so as to extend in the longitudinal direction from the radially outside to the lower side of the tray 109a, and its lower end is located above a drain groove 112c described later, and allows the drainage received by the tray 109a to pass downward. The partition wall 209a is connected to the radially inside of the tray 109a at a position facing the outer surface of the second portion 208b. The position facing the outer surface of the second portion 208b here refers to a position that is spaced apart enough to provide a sealing function due to surface tension even if drainage falls into the upper portion of the gap between the second portion 208b of the connector 208 and the partition wall 209a, and to reduce the amount of drainage flowing into the gap. The partition wall 209a is provided in a shape that is radially inward from the tip portion 208e of the drain cutter 208d. The shape that is radially inward from the tip portion 208e here refers to a shape that is radially inward enough that drainage cut off at the tip portion 208e does not fall onto the upper portion of the partition wall 209a. For example, the partition wall 209a forms a wall surface that extends upward from the tray 109a in the longitudinal direction.

[0046] Here, a description will be given of the flow of drainage leaking from the gap between the valve casing 101 and the valve rod 103 in this embodiment. First, a description will be given of flow C in FIG.

[0047] The drain leaking from the gap between the valve casing 101 and the valve rod 103 reaches the drain cutter 208d along the outer surface of the valve rod 103 and the connector 208. The drain reaching the drain cutter 208d is cut off by the drain cutter 208d and falls into the tray 109a of the drain pan 209. The drain that falls into the tray 109a of the drain pan 209 falls into the drain groove 112c through the first drain hole 109b. The drain that falls into the drain groove 112c is discharged to the outside from the drain groove 112c through the second drain hole 112d. Therefore, the drain does not remain inside the coupling 110 and inside the oil cylinder 106, and corrosion inside the oil cylinder 106 can be suppressed.

[0048] Next, flow B in Fig. 3(b) will be described. Drainage leaking from the gap between the valve casing 101 and the valve rod 103 falls directly into the tray 109a of the drain pan 209. The drainage that falls into the tray 109a of the drain pan 209 merges with flow C, passes through the first drain hole 109b, falls into the drain groove 112c, and is discharged from the drain groove 112c through the second drain hole 112d to the outside. Therefore, the drainage does not remain inside the coupling 110 and inside the oil cylinder 106, and corrosion inside the oil cylinder 106 can be suppressed.

[0049] As described above, according to the steam valve 200 of the present embodiment, even if the drain leaking from the gap between the valve casing 101 and the valve rod 103 falls, the partition wall 209a is provided at a position facing the outer surface of the second part 208b of the connector 208, so that the drain does not fall onto the upper part of the partition wall 209a but falls into the tray 109a of the drain pan 209. That is, the drain can be prevented from passing over the partition wall 209a and entering the gap between the connector 208 and the partition wall 209a. Even if the drain falls onto the upper part of the gap between the connector 208 and the partition wall 209a, the gap is small, and a sealing function due to the surface tension effect is exerted, so that the drain can be further prevented from entering the gap. As a result, corrosion can be prevented from occurring inside the oil cylinder 106.

[0050] In addition, the steam valve 200 of this embodiment is described as being equipped with the connector 208 having the drain cutout 208d and the drain pan 209 having the partition wall 209a, but the steam valve 200 only needs to have a structure that prevents drain from flowing into the oil cylinder 106. For example, a cup-shaped or disk-shaped cover may be attached to the existing connector 108 instead of the drain cutout 208d as a configuration having a function similar to that of the drain cutout 208d.

[0051] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the invention and its equivalents described in the claims. [Explanation of symbols]

[0052] 1...thermal power generation system, 2...boiler, 3...main steam pipe, 4...main steam stop valve, 5...steam control valve, 6...high pressure turbine, 7...low temperature reheat pipe, 8...check valve, 9...high temperature reheat pipe, 10...re-steam stop valve, 11...intercept valve, 12...intermediate pressure turbine, 13...crossover pipe, 14...low pressure turbine, 15...condenser, 16...condensate pipe, 17...feed pump, 18...high pressure turbine bypass pipe, 19...high pressure turbine bypass valve, 20...low pressure turbine bypass pipe, 21...low pressure turbine bypass valve, 100...steam valve, 101...valve casing, 101a...steam inlet, 101b...steam outlet, 102...valve seat, 103...valve stem, 104...valve body, 10 5...coupling mechanism, 106...oil cylinder, 107...drive mechanism, 108...connector, 108a...recess, 108b...recess, 109...drain pan, 109a...receiving tray, 109b...first drain hole, 110...coupling, 111...piston rod, 112...yoke, 112a...connecting piece, 112b...side wall, 112c...drain groove, 112d...second drain hole, 113...bolt, 200...steam valve, 205...coupling mechanism, 208...connector, 208a...first part, 208b...second part, 208c...third part, 208d...drain cutter, 208e...tip portion, 208f...machined surface, 209...drain pan, 209a...partition wall.

Claims

1. A connector connected to an end of a valve rod, the end being different from the one end of the valve rod. A drain pan provided radially outward from the connector about the axial direction of the valve rod, the drain pan having a partition wall facing an outer surface of the connector; A steam valve comprising:

2. The connector includes: a first portion including a recess connecting the different ends of the valve stem; a second portion that is provided on a lower side of the first portion in the axial direction and has an outer diameter in the radial direction smaller than that of the first portion; Including, The steam valve according to claim 1 , wherein the partition wall is disposed opposite an outer surface of the second portion.

3. The steam valve according to claim 2, further comprising a drain cutout provided at an end of the first portion that is not connected to the second portion, at the boundary between the first portion and the second portion.

4. The drain cut is A tip portion that is cut off at the radially outer tip; A machined surface machined on the upper side at a radially inner side than the tip portion; 4. The steam valve of claim 3, further comprising:

5. The steam valve according to claim 2 or 3, wherein the partition wall is provided in a shape that is radially inward from an outer surface of the first portion.

6. The steam valve according to claim 4 , wherein the partition wall is provided in a shape that is radially inward from the tip portion.

7. A steam turbine comprising the steam valve according to claim 1.

8. A thermal power generation system comprising the steam turbine according to claim 7.

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