JP6933538B2 - Steam valve gear and steam turbine plant equipped with it - Google Patents

Description

An embodiment of the present invention relates to a steam valve device and a steam turbine plant including the same.

In a typical conventional steam turbine plant, steam from the boiler is sent through a steam valve device to the steam turbine. After working in the steam turbine, the steam is returned to water by the condenser, boosted by the water supply pump, and circulated so that it is supplied to the boiler again.

The steam valve device consists of a main steam stop valve and a steam control valve arranged on the downstream side thereof. The main steam stop valve can instantly stop the steam flowing into the steam turbine in an emergency such as in a steam turbine. The steam control valve is for controlling the flow rate of steam supplied to the steam turbine.

Among steam valve devices applied to thermal power plants and the like, for example, a steam control valve handles high-temperature, high-pressure, and large-flow steam, and frequently opens and closes the valve body. For this reason, when the valve body starts to open or during the throttle process until the valve body closes, a drift or vortex flow occurs in the steam flow, and noise, vibration, erosion, and valve body due to the turbulence of the flow occur. In some cases, cracks may occur at the connection part of the valve stem that supports the valve rod. Recently, as the capacity of a single steam turbine has increased due to the efforts for ultra-supercritical pressure, the steam conditions (temperature, pressure) have become even higher, and such problems have tended to become more prominent.

Various measures have been conventionally taken against problems caused by such uneven flow of steam flow and eddy current. For example, there is known a technique for stabilizing the steam flow by providing a recessed portion having an edge on the peripheral edge on the bottom side of the valve body. Furthermore, in order to improve the efficiency of the steam turbine, the main steam stop valve, the steam control valve on the downstream side thereof, and the intermediate flow path portion arranged between them are used for the purpose of reducing the pressure loss when the valve of the steam valve device is opened. A steam valve device integrated with is known.

Japanese Unexamined Patent Publication No. 2006-63957 JP-A-2009-156040

As described above, various problems such as noise, vibration, erosion, and cracks at the connection portion of the valve stem have occurred due to the drift and eddy current of the steam flow during the opening and closing process of the steam control valve.

An object of the present invention is to provide a steam valve device capable of stabilizing the steam flow during the opening / closing process of the steam control valve and a steam turbine plant including the steam valve device.

The steam valve device of the embodiment is an intermediate flow path connecting the main steam stop valve, the steam control valve arranged on the downstream side of the main steam stop valve, and the main steam stop valve and the steam control valve. It is a steam valve device having a part. In the horizontal cross section of the flow path from the intermediate flow path portion to the steam control valve, the center line of the valve body of the steam control valve is eccentric to one side with respect to the center line of the intermediate flow path portion. On the other side opposite to one side, a straight portion in which the inner wall of the intermediate flow path portion and the inner wall of the casing of the steam control valve are in linear contact with each other is formed along the center line of the intermediate flow path portion, and the valve is formed. Of the space between the circumference of the body and the casing accommodating the valve body, steam is allowed to flow into the space on the other side of the valve body from the intermediate flow path portion along the straight line portion to form the valve body. It is configured to form a swirling flow around it and flow out while swirling toward the downstream of the valve seat.

The system diagram which shows the structure of the steam turbine plant of an embodiment. The vertical sectional view which shows the steam valve device of 1st Embodiment. A cross-sectional view taken along the line AA of FIG. The conceptual diagram which shows the flow of steam in the vertical cross section of the steam valve device of 1st Embodiment. FIG. 6 is a conceptual diagram showing the flow of steam in the cross section taken along the line AA of FIG. The vertical sectional view which shows the modification of 1st Embodiment. FIG. 6 is an enlarged view showing a main part of FIG. The vertical sectional view which shows the steam valve device of 2nd Embodiment. A cross-sectional view taken along the line AA of FIG. The conceptual diagram which shows the flow of steam in the vertical cross section of the steam valve device of 2nd Embodiment. FIG. 6 is a conceptual diagram showing a steam flow in a cross section taken along the line AA of FIG. The vertical sectional view which shows the steam valve device of 3rd Embodiment. A cross-sectional view taken along the line AA of FIG. The conceptual diagram which shows the flow of steam in the vertical cross section of the steam valve device of 3rd Embodiment. FIG. 6 is a conceptual diagram showing the flow of steam in the cross section taken along the line AA of FIG. The vertical sectional view which shows the schematic structure of the steam valve device of the modification. The conceptual diagram which shows the flow of steam in the vertical cross section of the steam valve device of a reference example. FIG. 6 is a conceptual diagram showing the flow of steam in the cross section taken along the line AA of FIG.

Hereinafter, the steam valve device of the embodiment and the steam turbine plant including the steam valve device will be described with reference to the drawings.

[Steam turbine plant configuration]
FIG. 1 is a system diagram showing an embodiment of a steam turbine plant provided with a steam valve device.

In this steam turbine plant, as shown in FIG. 1, steam from the boiler 20 is configured to be sent to the high-pressure steam turbine 10 after passing through the steam valve device 21. The steam valve device 21 has a main steam stop valve 1 and a steam control valve 2 arranged on the downstream side thereof. The steam after working in the high-pressure steam turbine 10 is reheated by the reheater of the boiler 20 via the check valve 7, and passes through the reheat steam stop valve 3 and the intercept valve 4 to the medium-pressure steam turbine. It is sent to 11 and then to the low pressure steam turbine 12 for further work. The steam discharged from the low-pressure steam turbine 12 is returned to water by the condenser 13, boosted by the water supply pump 14, and circulated so as to be supplied to the boiler 20 again.

In the example of FIG. 1, in order to improve the operational efficiency of the plant, the high-pressure turbine bypass valve 5 and the condenser of the boiler 20 connected from the upstream side of the main steam stop valve 1 to the upstream side of the condenser of the boiler 20 A low-pressure turbine bypass valve 6 connected to the condenser 13 is installed from the downstream side so that the boiler system can be independently circulated regardless of the turbine operation.

[Vapor valve device of the first embodiment]
FIG. 2 is a vertical cross-sectional view showing the steam valve device 21 according to the first embodiment, and FIG. 3 is a cross-sectional view taken along the line AA of FIG. Further, FIGS. 4 and 5 show the same configuration as in FIGS. 2 and 3, and the flow (streamline) of steam is schematically shown by arrows in the figure.

As shown in FIG. 2, the steam valve device 21 according to this embodiment has a main steam stop valve 1 on the upstream side, a steam control valve 2 arranged on the downstream side thereof, and an intermediate flow path communicating between them. It has a portion 30 and both the main steam stop valve 1 and the steam control valve 2 are of the vertical type (vertical installation). Depending on the combination of the main steam stop valve 1 and the steam control valve 2, there is a pattern in which the valve stems are orthogonal to each other, so the combination is not particularly limited. Further, FIGS. 2 to 5 show a state in which both the main steam stop valve 1 and the steam control valve 2 are open.

The main steam stop valve 1 has a first casing 31 that forms a first flow path 61, and a first valve body 32 that moves up and down in the first casing 31. The first casing 31 is formed with a first inlet portion 33 that opens horizontally to receive steam, and a first outlet portion 34 that opens vertically to discharge steam downward. .. At the first outlet portion 34, a first valve seat 35 forming an inwardly raised shape is arranged, and when the first valve body 32 rises or falls, the first valve body 32 and the first valve body 32 The valve seat 35 is configured to disengage and engage to open and close the first flow path 61.

A first valve lid 36 that can be opened at the time of maintenance is arranged on the upper portion of the first casing 31. A first valve rod 37 is attached to the first valve body 32, and the first valve rod 37 extends above the first valve body 32 and is the first valve lid 36 of the first casing 31. It penetrates the portion of the above and is connected to the first piston 39 in the first oil cylinder 38. Here, the first valve rod 37 is attached to the opposite side of the first outlet portion 34 with respect to the first valve body 32, and the first valve body 32 is attached to the first valve seat 35 from the first valve seat 35. When it is separated (that is, the first flow path 61 is opened), it is moved in the direction opposite to the first outlet portion 34. The strainer 40 is arranged inside the first casing 31 and outside the first valve body 32.

The steam control valve 2 has almost the same arrangement as the main steam stop valve 1, and has a second casing 41 forming the second flow path 71 and a second casing that moves up and down in the second casing 41. It has a valve body 42 and. The second casing 41 is formed with a second inlet portion 43 that opens horizontally to receive steam, and a second outlet portion 44 that opens vertically and discharges steam downward. .. A second valve seat 45 forming an inwardly raised shape is arranged at the second outlet portion 44, and when the second valve body 42 rises or falls, the second valve body 42 and the second valve body 42 The valve seat 45 is configured to disengage and engage to open and close the second flow path 71. Further, the axial directions of the second valve body 42, the second outlet portion 44, and the second valve seat 45 are concentric.

A second valve lid 46 that can be opened at the time of maintenance is arranged on the upper portion of the second casing 41. A second valve rod 47 is attached to the second valve body 42, and the second valve rod 47 extends above the second valve body 42 and is the second valve lid 46 of the second casing 41. It penetrates the portion and is connected to the second piston 49 in the second oil cylinder 48. Here, the second valve rod 47 is attached to the opposite side of the second outlet portion 44 with respect to the second valve body 42, and the second valve body 42 is attached to the second valve seat 45 from the second valve seat 45. When it is separated (that is, the second flow path 71 is opened), it is moved in the direction opposite to the second outlet portion 44.

The intermediate flow path portion 30 forms a pipeline connecting the first outlet portion 34 and the second inlet portion 43, and has a shape that bends from the vertical direction to the horizontal direction, and the angle thereof is approximately 90 degrees. be.

In the steam valve device 21 configured in this way, the main steam supplied from the boiler 20 (see FIG. 1) is horizontally contained in the first casing 31 of the main steam stop valve 1 from the first inlet 33. Then, it flows into the strainer 40, passes between the first valve body 32 and the first valve seat 35, passes downward through the first outlet portion 34, and passes through the main steam stop valve 1. The main steam that has passed through the main steam stop valve 1 passes through the intermediate flow path portion 30 and the direction of flow is changed from downward to horizontal, and the second steam control valve 2 second in the horizontal direction from the second inlet portion 43. It flows into the casing 41.

As shown in FIG. 3, the second casing 41 forms a steam passage portion 50 so as to surround the concentric second valve body 42. Further, geometrically in the horizontal cross section, the inner wall of the intermediate flow path portion 30 and the inner wall of the steam passage portion 50 (inner wall of the outer circumference) are in contact with each other to form a linear continuous wall surface (part B in FIG. 3). The center line 110 of the second valve body 42 (steam control valve 2) is eccentric by the length (L1) with respect to the center line 100 of the intermediate flow path portion 30.

In the steam valve device 21 having the above configuration, as shown in FIGS. 4 and 5, the steam flow passing through the intermediate flow path portion 30 is the second along a straight continuous wall surface (part B in FIG. 3). It flows into the second casing 41 of the steam control valve 2 from the side opposite to the eccentric direction (lower side in FIG. 5) of the valve body 42 (upper side in FIG. 5). Then, this steam flow flows into the steam passage portion 50 as a jet flow, and flows along the inner wall of the steam passage portion 50 while applying centrifugal force by passing through the annular steam passage portion 50. Therefore, the steam flow is forcibly swirled by the steam passage portion 50, passes through the steam throttle portion formed from the second valve body 42 and the second valve seat 45 while swirling, and further passes through the second valve body 42 and the second valve seat 45. It will flow out while turning toward the downstream of the valve seat 45 of 2.

That is, according to the steam valve device 21, in the range from the upstream intermediate flow path portion 30 to the downstream of the second valve seat 45, the steam flow is a regular continuous swirling flow from the conventional irregular and complicated flow. Will be improved. As a result, it becomes possible to obtain a stable flow without pressure fluctuation, and it is possible to suppress the generation of irregular shock waves in the steam throttle portion. In addition, in FIGS. 2 to 5, the case where the steam flow becomes a clockwise turning flow has been described, but the effect is the same even if the turning direction is opposite counterclockwise. Further, the second valve body 42 shown in FIGS. 2 to 5 has a convex (arc) shape toward the bottom side, but even if it has a convex (arc) shape, a regular continuous swirling flow acts. It is possible to stabilize the steam flow.

Further, as shown in FIGS. 6 and 7, a recessed portion 42b having an edge 42a along the peripheral edge portion may be provided on the bottom side of the second valve body 42. In this case, the shapes of the second valve body 42 and the edge 42a and the relative dimensions of each part shown in FIG. 7 are preferably as follows.

The second valve body 42 has a radius of curvature R, where the valve seat seat diameter is Do.
R = (0.52-0.6) Do
The second valve seat 45 has a radius of curvature r and a valve seat inner diameter Dth, respectively.
r ≧ 0.6 Do
Dth ≧ 0.8 Do
And set the diameter Di of the edge 42a to
Di ≧ 0.9 Do
Set to the range of. As a result, the steam flow can be further stabilized and the generation of unstable shock waves can be suppressed.

As described above, in the first embodiment, the steam flowing in from the intermediate flow path portion passes while swirling the steam throttle portion formed between the second valve body 42 and the second valve seat 45. .. This can be a workaround for vibrations based on irregular shock waves in the steam flowing here, that is, unstable shock waves accompanied by large pressure fluctuations that serve as a vibration source for the second valve body 42 and the like. , The synergistic effect of the effect of the above-mentioned regular continuous swirling flow and the effect of preventing the generation of these shock waves can be exhibited.

[Steam flow in reference example]
Here, unlike the first embodiment described above, in the case of the reference example in which the center line 100 of the intermediate flow path portion and the center line 110 of the second valve body (steam control valve) coincide with each other (not eccentric). The flow of steam will be described with reference to FIGS. 17 and 18. FIG. 17 shows the vertical cross-sectional configuration of the steam valve device 121, and FIG. 18 shows the flow of steam in the cross section taken along the line AA of FIG.

In this case, the steam after passing through the intermediate flow path collides with the second valve body on the downstream side and the inner wall of the second casing after passing around the valve body as a jet due to the inertia of the flow. .. This jet follows a trajectory that changes the direction of the flow downstream (outlet side) of the second valve seat, as shown by the streamlines (arrows) shown in FIGS. 17 and 18 after the collision, and as a result, the second jet flow. There is a very irregular and complex flow from around the valve body to around the second valve seat.

Further, since the above-mentioned extremely irregular and complicated flow is continuously generated around the steam throttle portion formed from the second valve body and the second valve seat, immediately before the steam throttle portion flows into the steam throttle portion. It causes pressure fluctuations in the steam flow, and the pressure fluctuations trigger the generation of irregular shock waves. Further, since a smooth steam flow cannot be obtained, the flow passing through the intermediate flow path becomes a jet flow and collides with the second valve body of the steam control valve and the inner wall of the second casing around the valve body to generate energy. A loss occurs, and a pressure loss as the steam valve device 121 occurs.

[Vapor valve device of the second embodiment]
FIG. 8 is a vertical cross-sectional view showing the configuration of the steam valve device 21a of the second embodiment, and FIG. 9 is a cross-sectional view taken along the line AA of FIG. Further, FIG. 10 shows the steam flow (streamline) in the vertical cross section of the steam valve device 21a with arrows, and FIG. 11 shows the steam flow (streamline) in the cross section taken along the line AA of FIG. ) Is indicated by an arrow. 8 to 11 show a state in which both the main steam stop valve 1 and the steam control valve 2 are open. The parts corresponding to the steam valve device 21 of the first embodiment shown in FIGS. 2 and 3 are designated by the same reference numerals, and duplicate description will be omitted.

The second embodiment differs from the first embodiment in that, as shown in FIG. 9, the shape of the inner wall of the second casing 41a is changed so that the shape of the steam passage portion 51 has a spiral shape. The structure of the other parts is the same. That is, the shape of the inner wall of the second casing 41a is the second shape that surrounds the outer periphery of the valve body 42 from the straight portion (part B in FIG. 9) that is the connecting portion with the intermediate flow path portion 30 in the horizontal cross section thereof. Along the inner circumference of the casing 41a, the radius of curvature from the center of the valve body 42 gradually decreases in a spiral shape. Further, the spiral-shaped inner wall is formed so that the cross-sectional area of the steam passage portion 51 gradually decreases so that the flow velocity of steam becomes uniform in the second casing 41a. Regarding this spiral shape, make it a geometric curve such as an involute curve or Pascal's cochlear curve (Limason curve), which is the locus of the tip of the thread when the thread is wound around a round cylinder and unwound while pulling the thread. It may be configured.

As in the first embodiment, the inner wall of the intermediate flow path portion 30 and the inner wall of the steam passage portion 50 (inner wall of the outer circumference) are in contact with each other to form a linear continuous wall surface (part B in FIG. 9). In the horizontal cross section, the center line 110 of the second valve body 42 (steam control valve 2) is geometrically eccentric with respect to the center line 100 of the intermediate flow path portion 30 by the length (L1).

In the steam valve device 21a having the above configuration, as shown in FIGS. 10 and 11, the steam flow passing through the intermediate flow path portion 30 is a second along a straight continuous wall surface (part B in FIG. 9). It flows into the second casing 41a of the steam control valve 2 from the side opposite to the eccentric direction (lower side in FIG. 9) of the valve body 42 (upper side in FIG. 9). Then, this steam flow becomes a jet flow and flows into the steam passage portion 51, and flows along the inner wall of the steam passage portion 51 while applying centrifugal force by passing through the spiral-shaped steam passage portion 51. It is forced to make a swirling flow more than the embodiment of. Therefore, the steam flow is forcibly swirled by the steam passage portion 51, passes through the steam throttle portion formed from the second valve body 42 and the second valve seat 45 while swirling, and further passes through the second valve body 42 and the second valve seat 45. It will flow out while turning toward the downstream of the valve seat 45 of 2. As a result, in the range from the intermediate flow path portion 30 upstream to the downstream of the second valve seat 45, the conventional irregular and complicated flow is improved to a regular continuous swirling flow. This makes it possible to obtain a stable flow without pressure fluctuations, and it is possible to suppress the occurrence of irregular impacts in the steam throttle portion.

In FIGS. 8 to 11, the case where the steam flow becomes a clockwise turning flow has been described, but the effect is the same even if the turning direction is opposite counterclockwise. Further, the second valve body 42 shown in FIGS. 8 to 11 has a convex (arc) shape toward the bottom side, but even if it has a convex (arc) shape, a regular continuous swirling flow acts. It is possible to stabilize the steam flow. Further, as shown in FIGS. 6 and 7, a recessed portion 42b having an edge 42a along the peripheral edge portion may be provided on the bottom side of the second valve body 42. In this case as well, the same effect as in the case of the first embodiment described above can be obtained.

[Vapor valve device of the third embodiment]
FIG. 12 is a vertical cross-sectional view showing the configuration of the steam valve device 21b of the third embodiment, and FIG. 13 is a cross-sectional view taken along the line AA of FIG. Further, FIG. 14 shows the steam flow (streamline) in the vertical cross section of the steam valve device 21b with arrows, and FIG. 15 shows the steam flow (streamline) in the cross section taken along the line AA of FIG. ) Is indicated by an arrow. 12 to 15 show a state in which both the main steam stop valve 1 and the steam control valve 2 are open.

Recently, as a measure for improving the efficiency of steam turbines, it is required to improve the efficiency in the partial load zone. For such a steam turbine plant that emphasizes efficiency in the partial load zone of the steam turbine, a nozzle speed control method aimed at reducing pressure loss when the valve is opened is suitable. The nozzle speed control method is a partial load band of the steam turbine, and the steam control valve is partially opened to the vicinity of full opening, so that the throttle loss is small. In a nozzle speed control type steam turbine plant, a nozzle box, which is a member for supplying steam to the turbine section of the steam turbine, is used so as to be divided into a plurality of sections in the circumferential direction. When applied to a nozzle speed control type steam turbine plant, it is necessary to install as many steam control valves as the number corresponding to the number of sections divided in the circumferential direction of the nozzle box of the steam turbine.

In the third embodiment, in order to apply to a nozzle speed control type steam turbine plant, a plurality of steam control valves 2 and 2a are combined with the main steam stop valve 1. In the steam valve device 21b shown in FIGS. 12 and 13, as an example, one main steam stop valve 1 is provided with two steam control valves 2 and 2a arranged on the downstream side of the main steam stop valve 1. The configuration includes one main steam stop valve 1 and one intermediate flow path portion 30 connecting between the two steam control valves 2 and 2a.

As shown in FIG. 13, the second casing 41 of the steam control valve 2 forms a steam passage portion 52 so as to surround the second valve body 42, and geometrically an intermediate flow path in the horizontal cross section. The center line 120 of the second valve body 42 (steam control valve 2) is eccentric to one side (lower in FIG. 13) by the length (L2) with respect to the center line 100 of the portion 30.

On the other hand, the second casing 81 of the steam control valve 2a forms a steam passage portion 92 so as to surround the second valve body 82, and geometrically the center line of the intermediate flow passage portion 30 in the horizontal cross section. The center line 130 of the second valve body 82 (steam control valve 2a) is eccentric to the other (upper in FIG. 13) by the length (L2) with respect to 100. Since the length (L2) is the same for both the steam control valve 2 and the steam control valve 2a, they are arranged symmetrically with respect to the center line 100 of the intermediate flow path portion 30.

The inner wall of the connection portion between the second casing 41 and the second casing 81, which is located on the extension of the center line 100 of the intermediate flow path portion 30, has a protruding portion protruding toward the intermediate flow path portion 30 side. 90 is formed. The protruding portion 90 has a shape that gradually tapers toward the intermediate flow path portion 30 side (left side in FIG. 13) in the horizontal cross section shown in FIG. Further, the surfaces 90a and 90b on both sides of the projecting portion 90 sandwiching the center line 100 of the intermediate flow path portion 30 are arcuate in shape according to the shapes of the inner walls of the second casing 41 and the second casing 81.

Then, the radius of curvature from the center of the second valve body 42 gradually decreases along the inner circumference of the second casing 41 surrounding the outer circumference of the second valve body 42 from the protruding portion 90 in a spiral shape. The radius of curvature from the center of the second valve body 82 is gradually reduced from the protruding portion 90 along the inner circumference of the second casing 81 surrounding the outer circumference of the second valve body 82. The shape is formed, and the steam passage portions 52 and 92 are formed in a mirror-symmetrical manner so as to surround the second valve bodies 42 and 82. The protruding portion 90 acts to divide the steam flowing in from the intermediate flow path portion 30 into two, and further, the respective steam passage portions 52 and 92 so that the flow velocity of the passing steam becomes uniform. , The cross-sectional area of the passage is gradually reduced. Regarding this spiral shape, a geometric curve such as an involute curve or Pascal's cochlear curve (Limason curve), which is the locus of the tip of the thread when the thread is wound around a round cylinder and unwound while pulling the thread, is used. It may be formed.

In the steam valve device 21b of the third embodiment having the above configuration, the steam flowing in from the intermediate flow path portion 30 is divided into two by the protruding portion 90, and the surfaces 90a and 90b and the third of the spirally shaped protruding portions 90 are formed. By passing through the inner walls of the casings 41 and 81 of No. 2 as a flow, a clockwise or counterclockwise turning flow is forcibly created because of the reflection symmetry.

That is, the steam flow that has flowed into the second casings 41 and 81 becomes a jet flow and flows into the steam passages 52 and 92, and by passing through the steam passages 52 and 92, the steam passage while applying centrifugal force. It flows along the inner walls of the portions 52, 92, and is made to be a swirling flow by the spiral type steam passage portions 52, 92 as in the second embodiment. Then, the steam throttle portion formed from the second valve bodies 42, 82 and the second valve seats 45, 85 is also swiveled, and eventually toward the downstream of the second valve seats 45, 85, the clock. It will flow out while turning in each turning direction of turning or counterclockwise.

As a result, a regular and continuous swirling flow is improved in the range from the upstream intermediate flow path portion 30 to the downstream of the second valve seats 45 and 85, respectively, so that a stable flow without pressure fluctuation can be obtained. This makes it possible to suppress the generation of irregular shock waves in the steam throttle section. Further, since the turbulence of the steam flow of the steam passage portions 52 and 92 is fundamentally improved, not only the pressure loss of the steam valve device 21b as a whole can be reduced, but also the efficiency including the operation of the steam turbine can be reduced. It is effective as an improvement measure, and the effect obtained as a whole steam turbine plant is great.

In each of the above-described embodiments, the common intermediate flow path portion 30 forms a pipeline connecting the first outlet portion 34 and the second inlet portion 43, and the angle thereof is 90 °. However, as shown in FIG. 16, the angle may be an inclined structure such as 45 °. Further, although not shown, the intermediate flow path portion 30 may have a large arc elbow structure having an angle of 90 °. In FIG. 16, the same reference numerals are given to the portions corresponding to those in FIG. 2 and the like.

Although some 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 embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

1 ... Main steam stop valve, 2, 2a ... Steam control valve, 3 ... Reheat steam stop valve, 4 ... Intercept valve, 5 ... High pressure turbine bypass valve, 6 ... Low pressure turbine bypass valve, 7 ... Check valve, 10 ... High-pressure steam turbine, 11 ... Medium-pressure steam turbine, 12 ... Low-pressure steam turbine, 13 ... Water recovery device, 14 ... Water supply pump, 20 ... Boiler, 21,21a, 21b, 121 ... Steam valve device, 31 ... First casing , 32 ... 1st valve body, 33 ... 1st inlet, 34 ... 1st outlet, 35 ... 1st valve seat, 36 ... 1st valve lid, 37 ... 1st valve rod, 38 ... 1st oil cylinder, 39 ... 1st piston, 40 ... steamer, 41,81 ... second casing, 42,82 ... second valve body, 43,83 ... second inlet, 44,84 ... 2nd outlet, 45, 85 ... 2nd valve seat, 46 ... 2nd valve lid, 47 ... 2nd valve rod, 48 ... 2nd oil cylinder, 49 ... 2nd piston, 50, 51, 52, 92 ... Steam flow path portion, 100 ... Center line of intermediate flow path portion, 110, 120, 130 ... Center line of second valve body.

Claims (7)

A steam valve device having a main steam stop valve, a steam control valve arranged on the downstream side of the main steam stop valve, and an intermediate flow path portion connecting the main steam stop valve and the steam control valve. There,
In the horizontal cross section of the flow path from the intermediate flow path portion to the steam control valve, the center line of the valve body of the steam control valve is eccentric to one side with respect to the center line of the intermediate flow path portion.
On the other side opposite to the one side, a straight portion in which the inner wall of the intermediate flow path portion and the inner wall of the casing of the steam control valve are in linear contact with each other is formed along the center line of the intermediate flow path portion.
Of the space between the periphery of the valve body and the casing accommodating the valve body, steam is allowed to flow into the space on the other side of the valve body from the intermediate flow path portion along the straight line portion, and the valve. A steam valve device characterized in that it forms a swirling flow around the body and flows out while swirling toward the downstream of the valve seat. A steam throttle portion composed of the valve body and a valve seat on which the valve body is seated.
The valve body has a radius of curvature R, where the valve seat seat diameter is Do.
R = (0.52-0.6) Do
The valve seat has a radius of curvature r and a valve seat inner diameter Dth, respectively.
r ≧ 0.6 Do
Dth ≧ 0.8 Do
In the range of
Further, on the bottom side of the valve body, a recessed portion having an edge on the edge is provided, and the edge has an edge diameter Di.
Di ≧ 0.9 Do
The steam valve device according to claim 1, wherein the range is set to. The shape of the inner wall of the casing is a spiral shape in which the radius of curvature from the center of the valve body gradually decreases along the inner circumference of the casing surrounding the outer circumference of the valve body from the straight portion in the horizontal cross section. The steam valve device according to claim 1 or 2, wherein the steam valve device is characterized in that. Any of claims 1 to 3, wherein the space between the inner wall of the casing and the valve body has a shape in which the cross-sectional area is gradually reduced so that the passing flow velocity of the passing steam becomes uniform. The steam valve device according to item 1. The main steam stop valve, the first and second steam control valves arranged on the downstream side of the main steam stop valve, and the main steam stop valve and the first and second steam control valves are connected. It is a steam valve device having an intermediate flow path portion to be operated.
In the horizontal cross section of the flow path from the intermediate flow path portion to the first and second steam control valves, the center line of the valve body of the first steam control valve is relative to the center line of the intermediate flow path portion. Is eccentric to one side, and the center line of the valve body of the second steam control valve is eccentric to the other side opposite to the one side.
A protruding portion protruding toward the intermediate flow path portion is formed at an intermediate portion between the casing of the first steam control valve and the casing of the second steam control valve.
Of the space between the periphery of the valve body of the first steam control valve and the casing of the first steam control valve, the space on the other side is the intermediate flow path portion along the protrusion. A swirling flow is formed around the valve body of the first steam control valve by inflowing steam from the steam control valve.
Of the space between the periphery of the valve body of the second steam control valve and the casing of the second steam control valve, in the space on one side thereof, the intermediate flow path portion along the protrusion. It is configured to allow steam to flow in from and form a swirling flow around the second valve body .
The steam valve device is characterized in that the protruding portion is located on an extension line of the center line of the intermediate flow path portion. The shape of the inner wall of the casing of the first steam control valve and the shape of the inner wall of the casing of the second steam control valve have a horizontal cross section thereof.
The radius of curvature from the center of the valve body of the first steam control valve is along the inner circumference of the casing of the first steam control valve that surrounds the outer periphery of the valve body of the first steam control valve from the protrusion. It is made into a spiral shape that gradually becomes smaller,
The radius of curvature from the center of the valve body of the second steam control valve is along the inner circumference of the casing of the second steam control valve that surrounds the outer periphery of the valve body of the second steam control valve from the protrusion. The steam valve device according to claim 5, wherein the steam valve device has a spiral shape that gradually becomes smaller. With the boiler
A steam turbine that introduces the main steam generated by the boiler and is driven by the energy of the main steam,
At least one steam valve device located between the boiler and the steam turbine to control the flow of the main steam.
It is a steam turbine plant with
The steam turbine plant according to any one of claims 1 to 6, wherein the steam valve device is the steam valve device.

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