JP5502792B2 - Steam valves and power generation equipment - Google Patents

Description

  Embodiments described herein relate generally to a steam valve installed in a system connecting a steam turbine and a pressure device, and a power generation facility in which the steam valve is used.

  In a mechanical drive or steam turbine for power generation and a steam turbine of a thermal power / nuclear power plant, steam used as energy for rotating the turbine is supplied to the turbine via a steam valve. The steam valve includes a casing, a valve body, a valve stem, a guide bush, and an upper lid. The casing has a steam inlet and a steam outlet, and a valve seat is formed between them. The valve body is supported by a valve stem and fixed by a cap, and is disposed so as to contact the valve seat from the steam inlet side. The valve stem is guided by a guide bush fixed to the casing on the steam outlet side, and is driven by an actuator. The casing has an opening formed on the extension of the valve stem between the valve seat and the steam inlet. A sheet surface is formed at the edge of the opening, and a gasket is attached. The upper lid is fixed by a stud bolt and nut attached to the outer periphery of the opening.

Japanese Utility Model Publication No. 58-108201 JP-A-8-93407 JP 11-336930 A

  In the case of the steam valve having the above-described structure, the bolt for fixing the upper lid to the casing is a tightening necessary to maintain and secure the steam seal against the internal pressure acting on the upper lid in order to secure the tightening force of the upper lid. In order to obtain force, it is necessary to manage bolt elongation and tightening torque. And the tightening force requested | required of the volt | bolt for fixing an upper cover becomes large, so that internal pressure is large. In order to improve energy efficiency, turbine plants are using higher pressure steam, and it is necessary to change the structure such as using high-strength materials, increasing the bolt size, or increasing the number of bolts. . Therefore, it takes time to attach the upper cover of the steam valve.

  Accordingly, there are provided a steam valve having a structure for fixing an upper lid so as to be able to withstand an internal pressure regardless of the strength and quantity of bolts and nuts, and a power generation facility using the steam valve.

  The steam valve of one embodiment includes a casing, a valve seat, a valve body, a valve stem, a mounting seat, and an upper lid. The casing has a steam inlet and a steam outlet. The valve seat is disposed between the steam inlet and the steam outlet. The valve body comes into contact with the valve seat from the steam inlet side to block the flow of steam. The valve stem supports the valve body from the steam outlet side. The mounting seat is open on the steam inlet side on the extension line of the valve stem, and a seal surface is formed on the inner peripheral edge. The upper lid is attached to the mounting seat from the inside of the casing, and seals steam in the casing by bringing the outer peripheral edge into contact with the sealing surface.

Schematic which shows the circulation system of the vapor | steam of power generation equipment provided with the steam valve of 1st Embodiment. Sectional drawing of the steam valve shown in FIG. The top view of the steam valve shown in FIG. Sectional drawing of the junction part of the upper cover and casing of the steam valve shown in FIG. Sectional drawing of the steam valve of 2nd Embodiment. The top view which notched the steam valve shown in FIG. 5 partially. Sectional drawing of the junction part of the upper cover and casing of the steam valve shown in FIG. Sectional drawing of the steam valve of 3rd Embodiment. Sectional drawing of the junction part of the upper cover and casing of the steam valve shown in FIG. Sectional drawing of the steam valve of 4th Embodiment. The top view of the steam valve shown in FIG. Sectional drawing of the steam valve of 5th Embodiment. The top view which notched the steam valve shown in FIG. 12 partially. Sectional drawing of the steam valve of 6th Embodiment. The top view of the steam valve shown in FIG. Sectional drawing of the junction part of the upper cover and casing of the steam valve shown in FIG.

  A power generation facility 1 including a steam valve 10 according to a first embodiment will be described with reference to FIGS. 1 to 4. A power generation facility 1 shown in FIG. 1 includes a steam generator 2, a turbine 3, a steam valve 10, a condenser 4, and a feed water pump 5. The steam generator 2 generates water vapor using a heat source such as a boiler. The turbine 3 is rotated by the steam produced by the steam generator 2. Three types of turbines, a high-pressure turbine 31, an intermediate-pressure turbine 32, and a low-pressure turbine 33, are connected coaxially. The steam is sent from the steam generator 2 to the turbine 3 by a steam pipe 6. Steam valves 10 for various purposes are installed in the middle of the steam pipe 6.

  A steam pipe 6 between the steam generator 2 and the high-pressure turbine 31 is provided with a first steam valve 10A for stopping the main steam and a second steam valve 10B for controlling the flow rate. The steam pipe 6 between the steam generator 2 and the intermediate pressure turbine 32 has a third steam valve 10C for stopping the reheat steam and a fourth steam valve 10D for adjusting the flow rate of the reheat steam. is set up. The reheat steam is steam reheated by the steam generator 2 in order to supply steam recovered from the high pressure turbine 31 to the intermediate pressure turbine 32. The first steam valve 10A is called a main steam stop valve, the second steam valve 10B is called a steam control valve, the third steam valve 10C is called a reheat steam stop valve, and the fourth steam valve 10D is called an intercept valve.

  The steam heated by the steam generator 2 passes through the first steam valve 10 </ b> A and the second steam valve 10 </ b> B, works in the high-pressure turbine 31, and then passes through the check valve 7 to pass through the steam generator 2. To the reheater 21. The reheated steam superheated by the reheater 21 flows into the intermediate-pressure turbine 32 and further the low-pressure turbine 33 through the third steam valve 10C and the fourth steam valve 10D to work. The steam that exits the low-pressure turbine 33 is sent to the condenser 4 and returned to the water. The steam that has been returned to water by the condenser 4 is supplied to the steam generator 2 by the feed water pump 5. In this way, the steam circulates between the steam generator 2 and the turbine 3.

  Further, in order to increase the operation efficiency of the power generation facility 1, a high-pressure turbine bypass is connected to the steam pipe 6 connected between the steam generator 2 and the first steam valve 10A and upstream of the reheater 21 of the steam generator 2. A fifth steam valve 10E is installed as a valve, and a sixth steam valve 10F is installed as a low-pressure turbine bypass valve in the steam pipe 6 connected to the condenser 8 from the downstream side of the reheater 21 of the steam generator 2. The The steam is circulated between the steam generator 2 and the condenser 8 regardless of the operation of the turbine 3 by the steam pipe 6 in which the fifth steam valve 10E and the sixth steam valve 10F are installed.

  Since the structures of the first to sixth steam valves 10A, 10B, 10C, 10D, 10E, and 10F are all the same, the steam valve 10 will be described with reference to FIGS. The steam valve 10 shown in FIG. 2 includes a casing 11, a valve seat 12, a valve body 13, a valve rod 14, a mounting seat 15, and an upper lid 16. The casing 11 has a steam inlet 111 and a steam outlet 112. The steam inlet 111 and the steam outlet 112 are each connected to the steam pipe 6.

  As shown in FIG. 2, the valve seat 12 is disposed between the steam inlet 111 and the steam outlet 112 and is formed toward the steam inlet 111 side. The valve body 13 comes into contact with the valve seat 12 from the steam inlet 111 side to block the steam flow. The valve stem 14 passes through the casing 11 on the steam outlet 112 side, and supports the valve body 13 from the steam outlet 112 side. The valve body 13 is fixed to the end of the valve stem 14 by a main valve cap 131. A guide bush 113 is attached to the casing 11 where the valve stem 14 penetrates. The valve stem 14 is guided by the guide bush 113.

  The mounting seat 15 is open on the steam inlet 111 side on the extension line of the valve rod 14, and a seal surface 152 is formed on the lower surface of the flange portion 151 extending toward the center. As shown in FIG. 3, the upper lid 16 is a non-circular shape having a long side 161 and a short side 162, and a corner portion 163 that connects these with a circular arc. Therefore, the mounting seat 15 corresponding thereto is also a non-circular shape having a long side 153 and a short side 154. The upper lid 16 is attached to the attachment seat 15 from the inside of the casing 11.

  When the upper lid 16 is attached to the mounting seat 15, the upper lid 16 is rotated with respect to the attached state, is inclined and inserted through the opening, and is returned to the horizontal while being rotated toward the attached state. The upper lid 16 has a seal surface 164 formed on the outer peripheral edge thereof, and makes the seal surface 164 contact the seal surface 152 of the mounting seat 15. The sealing surface 152 of the casing 11 and the sealing surface 164 of the upper lid 16 are machined along the circumferential direction and seal the steam by a so-called metal seal that is in direct contact. The upper lid 16 is fixed by a stud bolt 165 and a nut 166 attached from the outside of the mounting seat 15, thereby sealing the steam in the casing 11. A steam chamber of the steam valve 10 is formed by the casing 11 and the upper lid 16.

  In a state where the turbine is operated, the steam pressure acts as an internal pressure in the steam chamber of the steam valve 10. Accordingly, the upper lid 16 is pressed toward the sealing surface 152 of the flange portion 151 of the mounting seat 15. The surface pressure required between the casing 11 and the upper lid 16 to contain the steam is ensured by the internal pressure that the upper lid 16 receives from the steam.

  Since the pressure applied to the steam chamber acts on the upper lid 16, the fastening force required for the studs 165 and nuts 166 to fix the upper lid 16 to the mounting seat 15 of the casing 11 is the case where the upper lid 16 is attached to the outside of the casing 11. It may be smaller than That is, the fastening force of the implantation bolt 165 and the nut 166 may be a level necessary for fixing the upper lid 16 to the seal surface 152 of the flange 151 in a state where the internal pressure is not applied to the steam chamber. Therefore, the size of the studs 165 and nuts 166 may be small, and the quantity thereof may be small. Therefore, the number of parts of the steam valve 10 is reduced, and the workability of attaching and removing the upper lid 16 is improved.

  Below, the steam valve 10 of 2nd-6th embodiment is demonstrated. The steam valve 10 of each embodiment is used as the steam valve 10 of the power generation facility 1 described in the first embodiment. The configuration of the power generation facility 1 takes into account the description in the first embodiment and FIG. Further, configurations having the same function as the configuration of the steam valve 10 in the first embodiment are denoted by the same reference numerals in the drawings of the respective embodiments, and the detailed description corresponds to the description of the first embodiment. And drawings.

  The steam valve 10 of 2nd Embodiment is demonstrated with reference to FIGS. As shown in FIGS. 5 to 7, in the steam valve 10, the upper lid 16 has a groove 167 on the outer peripheral edge outside the position where the stud bolt 165 is attached, and the groove 167 is provided with the sealing material 17. The sealing material 17 abuts on the sealing surface 152 of the mounting seat 15 of the casing 11. The bottom of the groove 167 is finished to have a surface roughness corresponding to the seal surface 164.

  The upper lid 16 is placed inside the casing 11 in the same manner as the upper lid 16 of the first embodiment, with the sealing material 17 fitted in the groove 167. The upper lid 16 is rotated and inclined so that the long side 161 of the upper lid 16 faces the short side 154 of the mounting seat 15 of the casing 11, and is inserted from the opening of the mounting seat 15. It is fixed to the flange 151 with a stud bolt 165 and a nut 166 attached from the outside of the casing 11. Since the sealing material 17 is provided, when the upper lid 16 is removed, the maintenance and management of the sealing surface 152 of the casing 11 and the sealing surface 164 of the upper lid 16 are easy.

  The steam valve 10 of 3rd Embodiment is demonstrated with reference to FIG. 8 and FIG. As shown in FIGS. 8 and 9, in the steam valve 10, the joint structure between the mounting seat 15 of the casing 11 and the upper lid 16 is different from the case of the first and second embodiments. As shown in FIG. 9, the seal surface 152 formed on the flange portion 151 of the mounting seat 15 is formed in a funnel shape having a constant inclination angle so that the opening diameter decreases from the inside to the outside of the casing 11. Yes. Therefore, the outer peripheral edge of the upper lid 16 is formed in a conical surface corresponding to the sealing surface 152 formed in the funnel shape.

  In the steam valve 10 of the third embodiment, the upper lid 16 has a groove 167 on the outer peripheral edge as in the second embodiment, and a sealing material 17 is attached thereto. In FIG. 9, the bottom of the groove 167 is formed in parallel with the bottom surface of the upper lid 16 facing the steam chamber. The bottom of the groove 167 may be formed in parallel to the seal surface 152 of the mounting seat 15 so that the thickness of the seal material 17 is uniform. Since the sealing surface 152 is formed in a funnel shape whose opening diameter decreases from the inside to the outside of the casing, the surface between the sealing surface 152 and the sealing material 17 when the upper lid 16 receives the internal pressure of the casing 11. Pressure is easy to stand. Instead of attaching the sealing material 17 to the upper lid 16, a sealing surface 164 is formed on the outer peripheral edge of the upper lid 16 outside the mounting bolt 165 as in the first embodiment, and the mounting seat 15 The vapor may be sealed by a metal seal that is in direct contact with the sealing surface 152.

  The steam valve 10 of 4th Embodiment is demonstrated with reference to FIG. 10 and FIG. The cross-sectional structure of the steam valve 10 of the fourth embodiment is the same as that of the steam valve 10 of the first embodiment as shown in FIG. As shown in FIG. 11, the steam valve 10 is different from the steam valve 10 of the first to third embodiments in the outer shape of the upper lid 16. The upper lid 16 in the steam valve 10 of the fourth embodiment has an angled portion 163 in which the long side 161 and the short side 162 are connected by the oblique side, and is formed in an octagon shape with the rectangular corners removed. However, the mounting seat 15 of the casing 11 corresponding to the upper lid 16 is formed with a corner having an arc.

  By being formed as described above, the opening of the mounting seat 15 can be enlarged with respect to the steam chamber of the same size. Moreover, since the upper lid 16 is formed in a shape close to a rectangle, the upper lid 16 can be easily placed in the steam chamber of the casing 11.

  The steam valve 10 of 5th Embodiment is demonstrated with reference to FIG. 12 and FIG. The cross-sectional structure of the steam valve 10 of the fifth embodiment is provided with a sealing material 17 on the outer peripheral edge of the upper lid 16 as in the steam valve 10 of the second embodiment as shown in FIG. As shown in FIG. 13, the outer shape of the upper lid 16 is an octagon having a corner portion 163 in which the long side 161 and the short side 162 are connected by a hypotenuse as in the steam valve 10 of the fourth embodiment. The groove 167 formed on the outer peripheral edge of the upper lid 16 is formed in a layer octagon in the outer shape, and the sealing material 17 fitted in the groove 167 is also formed in an octagon as shown in FIG. The steam valve 10 of the fifth embodiment configured as described above has the functions of both the steam valve 10 of the second embodiment and the steam valve 10 of the fourth embodiment.

  The steam valve 10 of 6th Embodiment is demonstrated with reference to FIGS. 14-16. In the steam valve 10 of the sixth embodiment, the outer peripheral shape of the upper lid 16 is the same as the outer peripheral shape of the upper lid 16 of the steam valve 10 of the first embodiment, as shown in FIG. It is comprised by the edge | side 162 and the corner | angular part 163 which connects these with a circular arc. 14 and 16, the steam valve 10 is different from the steam valve 10 of the first to fifth embodiments in the joining structure of the mounting seat 15 of the casing 11 and the upper lid 16.

  As shown in FIG. 16, the sealing surface 152 of the mounting seat 15 in the steam valve 10 of the sixth embodiment is formed in a curved surface having a constant cross-sectional shape that bulges inward toward the inside of the casing 11. Similarly, the outer peripheral edge of the upper lid 16 is formed in a curved surface having a constant cross-sectional shape that bulges toward the seal surface 152. The cross section at this time is a cross section along a plane perpendicular to the tangent along the horizontal plane with respect to the outer peripheral edge of the seal surface 152 or the upper lid 16. The outer peripheral edge of the upper lid 16 functions as a seal surface 164 that makes line contact with the seal surface 152. As shown in FIG. 16, the stud bolt 165 and the nut 166 for fixing the upper lid 16 to the mounting seat 15 are arranged inside the outer peripheral edge formed on the curved surface. When the range of the curved surface formed on the outer peripheral edge is large, a part of the hole of the stud bolt 165 may be hung on the outer peripheral edge. However, it does not cover the range that functions as the seal surface 164.

  In the steam valve 10 configured as described above, when the upper lid 16 is mounted on the mounting seat 15 of the casing 11, the upper lid 16 is mounted along the horizontal plane with respect to the mounted state, as in the first to fifth embodiments. In a state where the long side of the upper lid 16 is rotated so as to face the short side 154 of the flange portion 151 of the mounting seat 15, the upper lid 16 is inclined and inserted from the opening. Then, the upper lid 16 is returned to the horizontal state while being rotated toward the mounted state.

  Since the seal surface 152 of the flange portion 151 and the seal surface 164 formed on the outer peripheral edge of the upper lid 16 are formed as convex curved surfaces, even if the upper lid 16 is slightly deviated from the mounting seat 15, the casing 11. The seal surface 152 and the seal surface 164 of the upper lid 16 are easily in line contact over the entire circumference. That is, it is easy to assemble the upper lid 16 with respect to the casing 11.

  In order to make it easier to assemble the upper lid 16 with respect to the casing 11, the outer peripheral shape of the upper lid 16 is formed in a non-circular shape having a long side 161 and a short side 162 as in the first to sixth embodiments. The seal surface 152 formed on the mounting seat 15 of the casing 11 and the seal surface 164 of the upper lid 16 are formed along a spherical surface having a certain radius. By doing in this way, even if the upper lid 16 is slightly inclined with respect to the horizontal plane or is slightly rotated around the axis of the valve stem 14, it is easy to assemble and the sealing surface of the casing 11 152 and the sealing surface 164 of the upper lid 16 are in close contact with each other and seal the vapor.

  Further, the outer shape of the upper lid is not limited to the steam valve of each of the above-described embodiments, but an elliptical shape, an oval shape, a hexagonal shape having a major axis and a minor axis have the same effect as the steam valve of each of the above-described embodiments. obtain.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Power generation equipment, 2 ... Steam generator, 3 ... Turbine, 6 ... Steam piping (pipe), 10 (10A, 10B, 10C, 10D, 10E, 10F) ... Steam valve, 11 ... Casing, 12 ... Valve seat, DESCRIPTION OF SYMBOLS 13 ... Valve body, 14 ... Valve rod, 15 ... Mounting seat, 16 ... Upper cover, 17 ... Sealing material, 111 ... Steam inlet, 112 ... Steam outlet, 152 ... Sealing surface, 161 ... Long side, 162 ... Short side, 163 ... corner, 164 ... sealing surface.

Claims (8)

A casing having a steam inlet and a steam outlet;
A valve seat disposed between the steam inlet and the steam outlet;
A valve body that comes into contact with the valve seat from the steam inlet side and blocks the flow of the steam;
A valve stem that supports the valve body from the steam outlet side;
A mounting seat that is open on the steam inlet side on the extension line of the valve stem and has a sealing surface formed on the inner periphery;
A steam valve, comprising: an upper lid which is attached to the mounting seat from the inside of the casing and has an outer peripheral edge abutted on the sealing surface to seal the steam in the casing. The steam valve according to claim 1, wherein the upper lid is a non-circular shape having a long side and a short side. The steam valve according to claim 1, wherein the upper lid includes a long side, a short side, and a corner portion connecting these with a circular arc. The steam valve according to claim 1, wherein the upper lid includes a long side, a short side, and a corner portion connecting these with a hypotenuse. The steam valve according to claim 1, wherein the upper lid is provided with a sealing material that is attached to an outer peripheral edge and abuts against the sealing surface. The sealing surface is formed in a funnel shape having a constant inclination angle with a smaller opening diameter from the inside to the outside of the casing,
The steam valve according to claim 1, wherein an outer peripheral edge of the upper lid is formed in a conical surface corresponding to the seal surface. The sealing surface is formed in a curved surface having a constant cross-sectional shape bulging toward the inside of the casing,
2. The steam valve according to claim 1, wherein an outer peripheral edge of the upper lid is formed into a curved surface having a constant cross-sectional shape that swells toward the seal surface, and is in line contact with the seal surface. A power generation facility including a steam generator, a turbine rotated by the steam, and a steam valve installed in a pipe through which the steam flows,
The steam valve
A casing having a steam inlet and a steam outlet;
A valve seat disposed between the steam inlet and the steam outlet;
A valve body that comes into contact with the valve seat from the steam inlet side and blocks the flow of the steam;
A valve stem that supports the valve body from the steam outlet side;
A mounting seat that is open on the steam inlet side on the extension line of the valve stem and has a sealing surface formed on the inner periphery;
An electric power generation facility comprising: an upper lid that is attached to the mounting seat from the inside of the casing and has an outer peripheral edge abutted on the sealing surface to seal the steam in the casing.

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