JP5175806B2 - Steam valve - Google Patents

Description

  The present invention relates to a steam valve having an outer casing and an inner casing used in a steam turbine plant, and in particular, the outer casing and the inner casing can be firmly fixed and workability during assembly and disassembly is improved. The present invention relates to a steam valve that can be improved.

  Conventionally, in a steam turbine plant of a thermal power / nuclear power plant, a steam valve has been used to control the flow of steam to each device in the plant.

  FIG. 11 shows a general steam turbine plant 100 in which a steam valve is used. In such a steam turbine plant 100, the steam generated in the superheater 101 a of the boiler 101 is supplied to the high-pressure turbine 105 through the steam valves (the main steam stop valve 103 and the steam control valve 104) of the main steam pipe 102 to expand. Do the job. The high-pressure exhaust steam discharged after the expansion work is guided to the reheater 101b of the boiler 101 through the check valve 107 of the high-pressure exhaust steam pipe 106, and is reheated, that is, reheated to become reheated steam. . The reheat steam is supplied to the intermediate pressure turbine 111 and the low pressure turbine 112 through the steam valves (reheat steam stop valve 109 and intercept valve 110) of the reheat steam pipe 108, and sequentially performs expansion work. The low-pressure exhaust steam discharged after finishing the expansion work in the low-pressure turbine 112 is guided to the condenser 113 and condensed to become condensate. The condensed water is boosted by the feed water pump 114 and supplied to the boiler 101.

  During this time, the high-pressure turbine 105, the medium-pressure turbine 111, and the low-pressure turbine 112 are rotationally driven, and a generator (not shown) connected to each of the turbines 105, 111, and 112 generates power.

  Connected between the main steam pipe 102 and the high-pressure exhaust steam pipe 106 is a high-pressure bypass pipe 115 for bypassing the high-pressure turbine 105 and supplying the main steam from the high-pressure exhaust steam pipe 106 to the reheater 101b of the boiler 101. Has been. One end of the high-pressure bypass pipe 115 is connected to the upstream side of the main steam stop valve 103 in the main steam pipe 102, and the other end is connected to the downstream side of the check valve 107 in the high-pressure exhaust steam pipe 106. A high-pressure turbine bypass valve 116 is provided in the middle of the high-pressure bypass pipe 115.

  A low pressure bypass pipe 117 for bypassing the intermediate pressure turbine 111 and the low pressure turbine 112 and supplying the reheat steam to the condenser 113 is connected between the reheat steam pipe 108 and the condenser 113. . One end of the low pressure bypass pipe 117 is connected to the upstream side of the reheat steam stop valve 109 in the reheat steam pipe 108, and the other end is connected to the condenser 113. Is provided with a low pressure turbine bypass valve 118. By providing the high-pressure bypass pipe 115 and the low-pressure bypass pipe 117 in this way, even when the turbines 105, 111, 112 are stopped, the main steam and the reheat steam are passed through the high-pressure bypass pipe 115 and the low-pressure bypass pipe 117, respectively. The boiler 101 can be operated independently by causing the steam to bypass and circulate.

  In recent years, in order to improve the power generation efficiency in the steam turbine plant 100, the temperature and pressure of steam supplied to each turbine 105, 111, 112 tend to increase. In this case, since the temperature and pressure of the steam flowing through the steam valve are increased, the load applied to the casing of the steam valve is increased, the allowable load of the casing is decreased, and the mechanical strength of the casing becomes a problem. There is.

  In order to cope with such a problem, a double casing type steam valve has been developed (for example, see Patent Documents 1 and 2). As an example, a double casing steam valve 120 shown in FIG. 12 has an outer casing 121 and an inner casing 122 accommodated in the outer casing 121. Among these, the inner casing 122 is locked by the cotter 123 and fixed in the outer casing 121. Further, a steam chamber 124 through which high-temperature and high-pressure steam flows is formed in the inner casing 122, and a gap portion 125 is formed between the outer casing 121 and the inner casing 122. In the gap portion 125, The steam is filled with steam at a lower temperature and lower pressure than the steam flowing through the steam chamber 124. In this manner, the outer casing 121 is prevented from being exposed to high-temperature and high-pressure steam, and high-temperature heat-resistant steel is used as the material forming the inner casing 122, but low-temperature heat-resistant steel is used as the material forming the outer casing. Can be used.

Japanese Patent Laid-Open No. 62-237909 JP 2005-48639 A

  Here, the steam flowing through the steam chamber 124 in the inner casing 122 causes fluid vibration as the valve is opened and closed. Further, as described above, when the materials of the outer casing 121 and the inner casing 122 are different, it is conceivable that the inner casing 122 expands more than the outer casing 121 due to high-temperature steam flowing through the steam chamber 124. Even in these cases, it is required that the fixing strength between the outer casing 121 and the inner casing 122 can withstand.

  Therefore, in order to firmly fix the outer casing 121 and the inner casing 122, it is necessary to attach the cotter 123 without forming a gap between the lower surface of the cotter 123 and the upper surface of the inner casing 122. However, in this case, the work of attaching and removing the cotter 123 becomes difficult, and the workability at the time of assembly and disassembly of the steam valve 120 is lowered.

  On the other hand, by providing a certain gap between the lower surface of the cotter 123 and the upper surface of the inner casing 122, it becomes possible to improve the workability of attaching and removing the cotter 123. The fixing strength with the inner casing 122 decreases.

  The present invention has been made in consideration of such points, and a steam valve that can firmly fix an outer casing and an inner casing and can improve workability at the time of assembly and disassembly is provided. The purpose is to provide.

  The present invention provides an outer casing having an engaging recess on an inner surface, an inner casing accommodated in the outer casing, and a locking body that engages with the engaging recess of the outer casing and locks the inner casing. A valve seat provided in the inner casing; a main valve that can freely contact the valve seat; and a drive unit that is connected to the main valve via a valve rod and drives the main valve, The steam valve is characterized in that a pressing mechanism for pressing the inner casing against the inner surface of the outer casing is interposed between the locking body and the inner casing.

  According to the present invention, the outer casing and the inner casing can be firmly fixed, and workability at the time of assembly and disassembly can be improved.

The figure which shows the whole structure of the steam valve in the 1st Embodiment of this invention. The figure which shows the detail of the press mechanism of the steam valve in the 1st Embodiment of this invention. The figure which shows the whole structure of the steam valve in the 2nd Embodiment of this invention. The figure which shows the upper surface of a spiral stopper in the steam valve in the 2nd Embodiment of this invention. The figure which shows the upper surface of a spiral shim in the steam valve in the 2nd Embodiment of this invention. AA line sectional view of Drawing 3. The figure which shows the whole structure of the steam valve in the 3rd Embodiment of this invention. The P section enlarged view of FIG. The figure which shows the whole structure of the steam valve in the 4th Embodiment of this invention. The Q section enlarged view of FIG. The figure which shows an example of a steam turbine plant. The figure which shows the whole structure of the conventional steam valve.

DESCRIPTION OF EXEMPLARY EMBODIMENTS First Embodiment Hereinafter, an embodiment of the invention will be described with reference to the drawings. Here, FIG. 1 and FIG. 2 are diagrams showing the steam valve in the first embodiment of the present invention.

  As shown in FIGS. 1 and 2, the steam valve 1 includes an outer casing 2 having a groove (engagement recess) 3 formed in an inner cylindrical portion 2 a, and an inner casing 4 accommodated in the outer casing 2. The cotter (locking body) 5 is provided above the inner casing 4 and engages with the groove 3 of the outer casing 2 to lock the inner casing 4. Among these, the cotter 5 is attached to the groove part 3 of the outer casing 2 at three locations in the circumferential direction (see FIG. 6).

  A step portion 7 is formed on the inner surface of the outer casing 2, and a jaw portion 6 that engages with the step portion 7 is formed on the outer surface of the inner casing 4. As described above, the inner casing 4 is configured such that its jaw portion 6 engages with the step portion 7 of the outer casing 2 and is accommodated in the outer casing 2. Further, as shown in FIGS. 1 and 2, the inner casing 4 includes an annular abutting plane (upper surface) 8 on which a later-described abutting plane 36 of a spiral shim 34 abuts and a center side of the abutting plane 8. And a raised portion 9 that is raised above the abutted flat surface 8.

  As shown in FIG. 1, a steam chamber 10 through which high-temperature (for example, 700 ° C.) and high-pressure steam flows is formed in the inner casing 4, and a gap is formed between the outer casing 2 and the inner casing 4. Part 11 is formed. The gap 11 is configured so that, for example, steam having a lower temperature and lower pressure than the steam flowing through the steam chamber 10 of the inner casing 4 is extracted from the plant and filled. This can prevent the outer casing 2 from being exposed to high-temperature and high-pressure steam. In this case, high temperature heat resistant steel is used as the material forming the inner casing 4, but low temperature heat resistant steel can be used as the material forming the outer casing 2.

  That is, as the low temperature heat resistant steel forming the outer casing 2, for example, a low chromium alloy heat resistant steel such as a ferritic alloy represented by Cr—Mo—V steel having a heat resistant temperature of about 570 degrees can be used. On the other hand, as the high-temperature heat-resistant steel forming the inner casing 4, it is preferable to use, for example, austenitic alloy steel or Ni-base alloy steel having practical strength at 700 degrees or more.

  A steam inlet pipe 12 serving as a steam inlet is provided on the steam inlet side of the outer casing 2. On the steam inlet side of the inner casing 4, a steam inlet connecting pipe 13 that guides the steam flowing in through the steam inlet pipe 12 of the outer casing 2 is provided. The steam inlet connecting pipe 13 extends to the outer casing 2, and a steam inlet connecting pipe seal ring 14 is provided between the steam inlet connecting pipe 13 and the outer casing 2. In this way, high-temperature and high-pressure steam flowing through the steam inlet pipe 12 is prevented from leaking into the gap portion 11.

  On the steam outlet side of the outer casing 2, a steam outlet pipe 15 serving as a steam outlet through the steam chamber 10 in the inner casing 4 is provided. A steam outlet connecting pipe 16 that guides the steam flowing out to the steam outlet pipe 15 of the outer casing 2 is provided on the steam outlet side of the inner casing 4. The steam outlet connecting pipe 16 extends to the outer casing 2, and a steam outlet connecting pipe seal ring 17 is provided between the steam outlet connecting pipe 16 and the outer casing 2. In this way, high-temperature and high-pressure steam flowing out to the steam outlet pipe 15 is prevented from leaking into the gap portion 11.

  A valve seat 20 is provided in the inner casing 4, that is, in the upper part of the steam outlet connecting pipe 16. A main valve 21 that can freely come into contact with the valve seat 20 is provided in the steam chamber 10, and a drive unit 23 is connected to the main valve 21 via a valve rod 22 to drive the drive unit 23. As a result, the main valve 21 is raised or lowered.

  On the upper surface of the upper casing, an upper lid 24 that partitions the upper portion of the gap 11 is attached by an upper lid mounting bolt 25. A guide bush 26 through which the valve rod 22 is slidable passes through the upper lid 24. The guide bush 26 extends through the inner casing 4 to the steam chamber 10, and a guide bush seal ring 27 is provided between the guide bush 26 and the inner casing 4. In this way, high-temperature and high-pressure steam flowing through the steam chamber 10 is prevented from leaking into the gap portion 11.

  A pressing mechanism 30 that presses the inner casing 4 against the inner surface of the outer casing 2 is interposed between the cotter 5 that locks the inner casing 4 and the inner casing 4.

  That is, as shown in FIGS. 1 and 2, the pressing mechanism 30 includes a locking plane (upper surface) 32 that is locked to the cotter 5 and a pressing surface 33 formed on the inner casing 4 side (lower side). An annular spiral stopper (rotating side pressing member) 31 is included that is rotatable in the circumferential direction. Between the spiral stopper 31 and the inner casing 4, a pressure receiving surface 35 that is pressed by the pressing surface 33 of the spiral stopper 31 and a contact plane (lower surface) 36 that contacts the contacted flat surface 8 of the inner casing 4. An annular spiral shim (fixed side pressing member) 34 is interposed.

  The pressing surface 33 of the spiral stopper 31 is inclined in the circumferential direction with respect to the locking plane 32, and the lower surface of the spiral stopper 31 is formed in a spiral shape. That is, as shown in FIG. 2, the spiral stopper 31 is cut at one place, and has a thick end 31a having a large thickness and a thin end 31b having a thin thickness. It is inclined in the clockwise direction when viewed from above so that the thickness gradually decreases from 31a toward the thin end portion 31b.

  The pressure receiving surface 35 of the spiral shim 34 is inclined in the circumferential direction so as to correspond to the pressing surface 33, and the upper surface of the spiral shim 34 is formed in a spiral shape. That is, like the spiral stopper 31, the spiral shim 34 is cut at one place, and has a thick end 34a having a large thickness and a thin end 34b having a small thickness. Inclined counterclockwise as viewed from above so that the thickness gradually decreases toward the thin end 34b.

  The spiral stopper 31 and the spiral shim 34 abut the pressure-receiving surface 35 of the spiral shim 34 against the pressing surface 33 of the spiral stopper 31 so that the thick end 31a of the spiral stopper 31 is replaced with the thick end 34a of the spiral shim 34. The total thickness of the spiral stopper 31 and the spiral shim 34 is smaller than the distance between the groove 3 on the inner surface of the outer casing 2 and the abutted flat surface 8 of the inner casing 4. It is configured.

  By rotating such a spiral stopper 31 in a direction in which the thickness is reduced (a clockwise direction when viewed from above in FIG. 2), the spiral stopper 31 is inserted through the spiral shim 34 by the wedge effect. A pressing mechanism 30 is configured to press the casing 4.

  Here, the outer diameter and inner diameter of the spiral stopper 31 are substantially the same as the outer diameter and inner diameter of the spiral shim 34, respectively, and the outer diameters of the spiral stopper 31 and the spiral shim 34 are cylindrical on the inner surface of the outer casing 2. It is substantially the same as the inner diameter of the portion 2a (see FIG. 6).

  Although not shown, an attachment hole for attaching a jig or the like may be provided in the spiral stopper 31. In this case, the spiral stopper 31 can be easily rotated by attaching a jig or the like to the attachment hole.

  Next, the operation of the present embodiment having such a configuration will be described.

  When assembling the steam valve 1 shown in FIGS. 1 and 2, first, the inner casing 4 to which the main valve 21, the valve rod 22, the guide bush 26 and the like are attached is accommodated in the outer casing 2. The abutting plane 36 of the spiral shim 34 is brought into contact with the abutted plane 8 of the accommodated inner casing 4, and the spiral shim 34 of the pressing mechanism 30 is placed on the inner casing 4.

  Next, the pressing surface 33 of the spiral stopper 31 is brought into contact with the pressure receiving surface 35 of the spiral shim 34, and the spiral stopper 31 is placed on the spiral shim 34. In this case, the spiral stopper 31 is placed so that the thick end portion 31a of the spiral stopper 31 is brought into contact with the thick end portion 34a of the spiral shim 34 in the circumferential direction. As a result, the locking plane 32 of the spiral stopper 31 can be positioned lower than the groove 3 on the inner surface of the outer casing 2.

  Next, the cotter 5 is attached to the groove 3 on the inner surface of the outer casing 2. In this case, since the locking plane 32 of the spiral stopper 31 is at a position lower than the groove 3, the cotter 5 can be easily attached to the groove 3.

  Next, the spiral stopper 31 is rotated in a direction in which the thickness is reduced (a clockwise direction when viewed from above in FIG. 2, hereinafter referred to as a pressing direction). In this case, the spiral shim 34 does not rotate due to the wedge effect, and the spiral stopper 31 presses the inner casing 4 via the spiral shim 34. As a result, the jaw portion 6 on the outer surface of the inner casing 4 is pressed against the step portion 7 on the inner surface of the outer casing 2.

  Next, the upper lid 24 is attached to the upper surface of the outer casing 2 using the upper lid mounting bolt 25, and the valve rod 22 is connected to the drive unit 23. Thereafter, the gap 11 formed between the outer casing 2 and the inner casing 4 is filled with steam at a lower temperature and a pressure than the steam at a high temperature and pressure flowing through the steam chamber 10, and the steam valve 1 shown in FIG. Assembled.

  When the steam valve 1 assembled in this way is opened to allow steam to flow, the drive unit 23 is driven to raise the valve rod 22. As a result, the main valve 21 rises away from the valve seat 20 and the steam valve 1 opens.

  In this case, high-temperature and high-pressure steam flows from the steam inlet pipe 12 of the outer casing 2, and the steam that flows in flows into the steam chamber 10 in the inner casing 4 through the steam inlet connecting pipe 13. The steam that has flowed into the steam chamber 10 passes between the valve seat 20 and the main valve 21 and flows out of the steam outlet pipe 15 through the steam outlet connecting pipe 16. In this way, high-temperature and high-pressure steam flows through the steam valve 1. In addition, the flow rate of the flowing steam can be adjusted by controlling the opening degree of the steam valve 1.

  While high-temperature and high-pressure steam flows through the steam valve 1, the space 11 between the outer casing 2 and the inner casing 4 is filled with low-temperature and low-pressure steam. This suppresses exposure of the inner surface of the outer casing 2 to high-temperature and high-pressure steam.

  When the steam valve 1 is closed to shut off the steam flow, the drive unit 23 is driven to lower the valve rod 22. As a result, the main valve 21 comes into contact with the valve seat 20 and the steam valve 1 is closed.

  When such a steam valve 1 is disassembled, first, low-temperature and low-pressure steam is released from the gap portion 11. Next, the valve stem 22 is removed from the drive unit 23, and the upper lid 24 is removed from the upper surface of the outer casing 2.

  Next, the spiral stopper 31 is rotated in the direction of increasing the thickness (the counterclockwise direction in FIG. 2, hereinafter referred to as the release direction). In this case, the spiral stopper 31 is rotated until the thick end 31 a of the spiral stopper 31 abuts on the thick end 34 a of the spiral shim 34. As a result, a gap can be formed between the cotter 5 and the spiral stopper 31.

  Next, the cotter 5 is removed from the groove 3 on the inner surface of the outer casing 2. In this case, since a gap is formed between the cotter 5 and the spiral stopper 31, the cotter 5 can be easily removed.

  Next, the spiral stopper 31 and the spiral shim 34 are sequentially removed, and then the inner casing 4 is removed from the outer casing 2 together with the main valve 21, the valve rod 22, the guide bush 26, etc., and the steam valve 1 is disassembled.

  Thus, according to the present embodiment, the inner casing 4 can be pressed against the inner surface of the outer casing 2 by the wedge effect by rotating the spiral stopper 31 in the pressing direction. Thereby, the outer casing 2 and the inner casing 4 can be firmly fixed. For this reason, when the steam flowing through the steam chamber 10 in the inner casing 4 causes fluid vibration due to the rising or lowering of the main valve 21, and the high temperature steam flowing through the steam chamber 10 causes the inner casing 4 to be exposed to the outside. Even when the casing 2 is expanded, it can have a sufficient fixing strength.

  Further, according to the present embodiment, as described above, when the inner casing 4 is fixed, the force for pressing the inner casing 4 against the outer casing 2 can be easily achieved by rotating the spiral stopper 31 in the pressing direction. Can be increased. On the other hand, when the inner casing 4 is removed, the cotter 5 can be easily removed by rotating the spiral stopper 31 in the releasing direction to form a gap between the cotter 5 and the spiral stopper 31. For this reason, the inner casing 4 can be easily fixed and removed, and the workability at the time of assembly and disassembly of the steam valve 1 can be improved.

Second Embodiment Next, a steam valve according to a second embodiment of the present invention will be described with reference to FIGS.

  The steam valve according to the second embodiment shown in FIGS. 3 to 6 is mainly different from the steam valve in that the stopper is provided with a stopper-side positioning hole and the spiral shim is provided with a shim-side positioning hole. Is substantially the same as the first embodiment shown in FIG. 1 and FIG. 3 to 6, the same parts as those of the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 3 to 6, the stopper 31 is provided with three stopper-side positioning holes (rotating-side positioning holes) 40a, 40b, and 40c penetrating in the axial direction in the spiral direction. Three sets of side positioning holes 40 a, 40 b, 40 c are provided in the spiral stopper 31. Further, three shim side positioning holes (fixed side positioning holes) 41a, 41b, 41c that are positioned on substantially the same circumference as the stopper side positioning holes 40a, 40b, 40c and penetrate in the axial direction are pressed on the spiral shim 34. The three shim side positioning holes 41 a, 41 b, 41 c are provided in the spiral shim 34 in order. These stopper side positioning holes 40a, 40b, 40c and shim side positioning holes 41a, 41b, 41c have substantially the same hole diameter, and the shim side positioning holes 41a, 41b, 41c are stopper side positioning holes 40a, 40b, 40c respectively.

  As shown in FIG. 4, a line segment connecting the center of the stopper side positioning hole 40a and the center point 31c of the spiral stopper 31 and the centers and center points of other stopper side positioning holes 40b adjacent to the stopper side positioning hole 40a. A line segment connecting 31c forms a predetermined angle α. Similarly, a line segment connecting the center of the stopper side positioning hole 40b and the center point 31c, and a line segment connecting the center of the other stopper side positioning hole 40c adjacent to the stopper side positioning hole 40b and the center point 31c, An angle α is formed. That is, the angle α is a circumferential angle between the centers of the stopper side positioning holes adjacent to each other with respect to the center point 31 c of the spiral stopper 31.

  As shown in FIG. 5, a line segment connecting the center of the shim side positioning hole 41a corresponding to the stopper side positioning hole 40a and the center point 34c of the spiral shim 34 and the shim side positioning hole 41b corresponding to the stopper side positioning hole 40b. A line segment connecting the center and the center point 34c forms a predetermined angle β. A line segment connecting the center of the shim side positioning hole 41b and the center point 34c and a line segment connecting the center of the shim side positioning hole 41c corresponding to the stopper side positioning hole 40c and the center point 34c have a predetermined angle γ. I am doing. That is, the angle β is the circumferential direction between the center of the shim side positioning hole 41a corresponding to the stopper side positioning hole 40a and the center of the shim side positioning hole 41b corresponding to the stopper side positioning hole 40b with respect to the center point 34c of the spiral shim 34. The angle γ is an angle between the center of the shim side positioning hole 41 b corresponding to the stopper side positioning hole 40 b and the center of the shim side positioning hole 41 c corresponding to the stopper side positioning hole 40 c with respect to the center point 34 c of the spiral shim 34. It is a circumferential angle.

  Here, the angle α is different from the angle β and the angle γ, and the angle β is different from the angle γ. In the present embodiment, as shown in FIGS. And γ have a relationship of α <β <γ.

  When the spiral stopper 31 is rotated in the pressing direction on such a spiral shim 34, first, it has an outer diameter that can be fitted into the stopper-side positioning holes 40a, 40b, 40c and the shim-side positioning holes 41a, 41b, 41c. At the same time, a taper pin (not shown) having a tapered tip is prepared.

  Next, a taper pin is inserted into the stopper side positioning holes 40a, 40b, and 40c. Here, as shown in FIG. 6, when the stopper side positioning holes 40a, 40b, 40c and the shim side positioning holes 41a, 41b, 41c are arranged, the stopper side positioning hole 40a with the smallest displacement amount between the holes is provided. Insert a taper pin into. Since the tip of the taper pin is tapered, the taper pin is inserted through the stopper side positioning hole 40a to the shim side positioning hole 41a. As a result, the spiral stopper 31 rotates in the pressing direction with respect to the spiral shim 34 by an angle corresponding to the amount of deviation between the stopper-side positioning hole 40a and the shim-side positioning hole 41a.

  Next, before the spiral stopper 31 is rotated, a taper pin is inserted into the stopper-side positioning hole 40b in which the displacement amount between the holes is the second smallest. As a result, the spiral stopper 31 further rotates in the pressing direction with respect to the spiral shim 34.

  Thereafter, by inserting a taper pin into the stopper-side positioning hole 40c, the spiral stopper 31 further rotates in the pressing direction with respect to the spiral shim 34. In this way, the spiral stopper 31 can be rotated in the pressing direction.

  On the other hand, when the spiral stopper 31 is rotated in the releasing direction on the spiral shim 34, by sequentially inserting the taper pins into the stopper side positioning holes 40c, 40b, 40a and the shim side positioning holes 41c, 41b, 41a, The spiral stopper 31 can be rotated in the release direction.

  As described above, according to the present embodiment, the taper pin 31 is sequentially inserted into the stopper side positioning holes 40a, 40b, 40c and the shim side positioning holes 41a, 41b, 41c, so that the spiral stopper 31 can be easily rotated in the pressing direction. Can be moved. On the other hand, the spiral stopper 31 can be easily rotated in the releasing direction by sequentially inserting the taper pins into the stopper side positioning holes 40c, 40b, 40a and the shim side positioning holes 41c, 41b, 41a. Therefore, the inner casing 4 can be reliably pressed against the inner surface of the outer casing 2 by the wedge effect, and the inner casing 4 can be easily fixed and removed, and the steam valve 1 can be assembled and disassembled. Workability can be improved.

  In this embodiment, the stopper 31 is provided with three stopper-side positioning holes 40a, 40b, 40c as one set, and three shim-side positioning holes 41a, 41b corresponding to them. 41c are provided, and the stopper side positioning holes 40a, 40b, 40c are formed at the same angular pitch (angle α). However, the present invention is not limited to this, and a line segment connecting the center of one stopper side positioning hole and the center point 31c of the spiral stopper 31 and the centers of other stopper side positioning holes adjacent to the stopper side positioning hole The angle formed by the line connecting the center point 31c is the line connecting the center of one shim-side positioning hole corresponding to the one stopper-side positioning hole and the center point 34c of the spiral shim 34, and the other The angle between the center of another shim-side positioning hole corresponding to the stopper-side positioning hole and the line connecting the center point 34c only needs to be different, and an arbitrary number of stopper-side positioning holes and shim-side positioning holes are provided. May be. In this case, the stopper side positioning holes may be formed at different angular pitches.

Third Embodiment Next, a steam valve according to a third embodiment of the present invention will be described with reference to FIGS.

  In the steam valve of the third embodiment shown in FIGS. 7 and 8, a plurality of stopper side protrusions are provided in the circumferential direction on the pressing surface of the spiral stopper, and the stopper side protrusion is provided on the pressure receiving surface of the spiral shim. The main difference is that there are provided a plurality of shim-side protrusions that engage only with one part and allow only rotation of the spiral stopper in one direction. Other configurations are the same as those shown in FIGS. This is substantially the same as the first embodiment. 7 and 8, the same parts as those of the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 7 and 8, a plurality of stopper-side protrusions (rotation-side protrusions) 50 that protrude toward the spiral shim 34 are provided on the pressing surface 33 of the spiral stopper 31 over the circumferential direction. . Each stopper-side protrusion 50 is formed on the release direction side, and an orthogonal surface 51 that is orthogonal to the pressing surface 33 and an inclined surface 52 that is formed on the pressing direction side of the orthogonal surface 51 and is inclined with respect to the orthogonal surface 51. And have. Among these, the inclined surface 52 is inclined so that the proximal end side is located closer to the pressing direction than the distal end side.

  A plurality of shim-side protrusions (fixed side) that engage the pressure-receiving surface 35 of the spiral shim 34 with the stopper-side protrusions 50 of the spiral stopper 31 and stop the spiral stopper 31 from rotating in the release direction. (Projecting part) 53 is provided. Each shim-side protruding portion 53 is formed on the pressing direction side, an orthogonal surface 54 orthogonal to the pressure receiving surface 35, and an inclined surface 55 formed on the release direction side of the orthogonal surface 54 and inclined with respect to the orthogonal surface 54. And have. Among these, the inclined surface 55 corresponds to the inclined surface 52 of the stopper-side protruding portion 50 and is inclined so that the distal end side is located on the pressing direction side with respect to the proximal end side.

  The inclined surface 52 of the stopper-side protrusion 50 abuts the corresponding inclined surface 55 of the shim-side protrusion 53, and the orthogonal surface 51 of the stopper-side protrusion 50 abuts the orthogonal surface 54 of the shim-side protrusion 53. ing.

  As described above, according to the present embodiment, when the spiral stopper 31 is rotated on the spiral shim 34 in the pressing direction, the inclined surface 52 of the stopper-side protruding portion 50 slides on the inclined surface 55 of the shim-side protruding portion 53. While moving, the stopper-side protrusion 50 can ride over the shim-side protrusion 53. However, since the orthogonal surface 51 of the stopper-side protrusion 50 is in contact with the orthogonal surface 54 of the shim-side protrusion 53 while the stopper-side protrusion 50 and the shim-side protrusion 53 are engaged, The rotation of the stopper 31 in the releasing direction is locked. Thereby, it is possible to prevent the spiral stopper 31 from rotating in the release direction, and to allow only the rotation of the spiral stopper 31 in the pressing direction. For this reason, it can prevent that the force which presses the inner casing 4 via the spiral shim 34 reduces, and can fix the outer casing 2 and the inner casing 4 still more firmly.

Fourth Embodiment Next, a steam valve according to a fourth embodiment of the present invention will be described with reference to FIGS.

  In the steam valve of the fourth embodiment shown in FIGS. 9 and 10, the pressing mechanism has an upper inclined stopper and a lower inclined stopper, and a wedge-shaped member is interposed between the upper inclined stopper and the lower inclined stopper. The main difference is that other configurations are substantially the same as those of the first embodiment shown in FIGS. 1 and 2. 9 and 10, the same parts as those in the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 9 and 10, the pressing mechanism 30 has an annular shape including a locking plane (upper surface) 61 that is locked to the cotter 5 and a pressing surface 62 formed on the inner casing 4 side (lower side). An upper inclined stopper (first pressing member) 60 is provided. Between the upper inclined stopper 60 and the inner casing 4, an annular shape including a pressure receiving surface 64 formed on the upper inclined stopper 60 side (upper side) and an abutting plane 65 that abuts against the abutted plane 8 of the inner casing 4. A lower inclined stopper (second pressing member) 63 is interposed.

  The pressing surface 62 of the upper inclined stopper 60 is inclined with respect to the locking plane 61 so that the wall thickness becomes thinner toward the inner peripheral side. Similarly, the pressure receiving surface 64 of the upper inclined stopper 63 is also inclined with respect to the contact plane 65 so that the wall thickness becomes thinner toward the inner peripheral side.

  An upper wedge surface 67 corresponding to the pressing surface 62 of the upper inclined stopper 60 and a lower wedge surface 68 corresponding to the pressure receiving surface 64 of the lower inclined stopper 63 between the upper inclined stopper 60 and the lower inclined stopper 63. A wedge-shaped member 66 including the is interposed. The upper wedge surface 67 and the lower wedge surface 68 of the wedge-shaped member 66 are inclined so that the thickness decreases toward the outer peripheral side. Three wedge-shaped members 66 are interposed between the upper inclined stopper 60 and the lower inclined stopper 63, and each wedge-shaped member 66 is disposed at a position corresponding to the cotter 5 (see FIG. 6). .

  The pressing mechanism 30 is configured to press the inner casing 4 through the lower inclined stopper 63 by the wedge effect by pushing each wedge-shaped member 66 to the outer peripheral side.

  Here, the outer diameter and inner diameter of the upper inclined stopper 60 are substantially the same as the outer diameter and inner diameter of the lower inclined stopper 63, respectively, and the outer diameters of the upper inclined stopper 60 and the lower inclined stopper 63 are the outer casing. 2 is substantially the same as the inner diameter of the cylindrical portion 2a on the inner surface.

  An annular spacer 70 is interposed between the inner peripheral side end 69 of each wedge-shaped member 66 and the raised portion 9 of the inner casing 4. Accordingly, the wedge-shaped member 66 pushed into the outer peripheral side can be reliably held, and the inner casing 4 can be reliably pressed by the wedge-shaped member 66.

  When assembling the steam valve 1 in the present embodiment shown in FIGS. 9 and 10, first, the inner casing 4 to which the main valve 21, the valve rod 22, the guide bush 26 and the like are attached is accommodated in the outer casing 2. The lower inclined stopper 63 of the pressing mechanism 30 is placed with the contact flat surface 65 of the lower inclined stopper 63 in contact with the abutted flat surface 8 of the accommodated inner casing 4.

  Next, the lower wedge surface 68 of the wedge-shaped member 66 is brought into contact with the pressure receiving surface 64 of the lower inclined stopper 63, and the three wedge-shaped members 66 are placed on the lower inclined stopper 63. In this case, the wedge-shaped member 66 is placed at a position corresponding to the mounting position of the cotter 5 to be mounted thereafter, and the inner peripheral side end 69 is in contact with the raised portion 9 of the inner casing 4. It is preferable to arrange them. As a result, the locking plane 61 of the upper inclined stopper 60 to be placed later can be positioned lower than the groove 3 on the inner surface of the outer casing 2.

  Next, the pressing surface 62 of the upper inclined stopper 60 is brought into contact with the upper wedge surface 67 of the wedge-shaped member 66, and the upper inclined stopper 60 is placed on the wedge-shaped member 66.

  Next, the cotter 5 is attached to the groove 3 on the inner surface of the outer casing 2. In this case, since the wedge-shaped member 66 is located on the inner peripheral side, the locking plane 61 of the upper inclined stopper 60 is at a position lower than the groove 3, and the cotter 5 can be easily attached to the groove 3.

  Next, the wedge-shaped member 66 is pushed into the outer peripheral side, and the spacer 70 is inserted between the inner peripheral side end portion 69 of the wedge-shaped member 66 and the raised portion 9 of the inner casing 4. In this case, the wedge-shaped member 66 presses the inner casing 4 via the lower inclined stopper 63 due to the wedge effect. As a result, the jaw portion 6 on the outer surface of the inner casing 4 is pressed against the step portion 7 on the inner surface of the outer casing 2.

  Thereafter, the upper lid 24 is attached to the upper surface of the outer casing 2 by using the upper lid mounting bolt 25, and the valve rod 22 is connected to the drive unit 23. Thereafter, the space 11 formed between the outer casing 2 and the inner casing 4 is filled with low-temperature and low-pressure steam, which is higher than high-temperature and high-pressure steam flowing through the steam chamber 10, and the steam shown in FIGS. The valve 1 is assembled.

  On the other hand, when dismantling such a steam valve 1, first, low-temperature and low-pressure steam is released from the gap portion 11. Next, the valve stem 22 is removed from the drive unit 23, and the upper lid 24 is removed from the upper surface of the outer casing 2.

  Next, the spacer 70 is removed, and the wedge-shaped member 66 is pulled out to the inner peripheral side so that the inner peripheral end portion 69 of the wedge-shaped member 66 contacts the raised portion 9 of the inner casing. Thereby, a gap can be formed between the cotter 5 and the upper inclined stopper 60.

  Next, the cotter 5 is removed from the groove 3 on the inner surface of the outer casing 2. In this case, since a gap is formed between the cotter 5 and the upper inclined stopper 60, the cotter 5 can be easily removed.

  Next, the upper inclined stopper 60, the wedge-shaped member 66, and the lower inclined stopper 63 are sequentially removed, and then the inner casing 4 is removed from the outer casing 2 together with the main valve 21, the valve stem 22, the guide bush 26, etc. Valve 1 is disassembled.

  Thus, according to the present embodiment, the inner casing 4 can be pressed against the inner surface of the outer casing 2 by the wedge effect by pushing the wedge-shaped member 66 to the outer peripheral side. Thereby, the outer casing 2 and the inner casing 4 can be firmly fixed.

  Further, according to the present embodiment, when the inner casing 4 is fixed, the wedge-shaped member 66 is pushed into the outer peripheral side, and the spacer 70 is attached to easily increase the force for pressing the inner casing 4 against the outer casing 2. be able to. On the other hand, when removing the inner casing 4, the spacer 70 is removed and the wedge-shaped member 66 is pulled out to the inner peripheral side, so that a gap is formed between the cotter 5 and the upper inclined stopper 60, and the cotter 5 can be easily formed. Can be removed. For this reason, the inner casing 4 can be easily fixed and removed, and the workability at the time of assembly and disassembly of the steam valve 1 can be improved.

DESCRIPTION OF SYMBOLS 1 Steam valve 2 Outer casing 2a Cylindrical part 3 Groove part 4 Inner casing 5 Cotter 6 Jaw part 7 Step part 8 Contact surface 9 Raised part 10 Steam chamber 11 Cavity part 12 Steam inlet pipe 13 Steam inlet connection pipe 14 Steam inlet connection Pipe seal ring 15 Steam outlet pipe 16 Steam outlet connection pipe 17 Steam outlet connection pipe seal ring 20 Valve seat 21 Main valve 22 Valve rod 23 Drive portion 24 Upper lid 25 Upper lid mounting bolt 26 Guide bush 27 Guide bush seal ring 30 Press mechanism 31 Spiral Stopper 31a Thick end portion 31b Thin end portion 32 Locking plane 33 Pressing surface 34 Spiral shim 34a Thick end 34b Thin end portion 35 Pressure receiving surface 36 Contact planes 40a, 40b, 40c Stopper side positioning holes 41a, 41b, 41c Shim side positioning hole 50 Stopper side protrusion 51 Orthogonal surface 52 Inclined surface 53 Shim side protrusion 5 4 orthogonal surface 55 inclined surface 60 upper inclined stopper 61 locking flat surface 62 pressing surface 63 lower inclined stopper 64 pressure receiving surface 65 abutting flat surface 66 wedge-shaped member 67 upper wedge surface 68 lower wedge surface 69 inner peripheral end 70 spacer 100 Steam turbine plant 101 Boiler 101a Superheater 101b Reheater 102 Main steam pipe 103 Main steam stop valve 104 Steam control valve 105 High pressure turbine 106 High pressure exhaust steam pipe 107 Check valve 108 Reheat steam pipe 109 Reheat steam stop valve 110 Intercept Valve 111 Medium-pressure turbine 112 Low-pressure turbine 113 Condenser 114 Feed water pump 115 High-pressure bypass pipe 116 High-pressure turbine bypass valve 117 Low-pressure bypass pipe 118 Low-pressure turbine bypass valve 120 Steam valve 121 External casing 122 Internal casing 123 Cotter 124 Steam chamber 125 Gap

Claims (6)

An outer casing having an engagement recess on the inner surface;
An inner casing housed in the outer casing;
A locking body that engages with the engagement recess of the outer casing and locks the inner casing;
A valve seat provided in the inner casing;
A main valve that can freely contact the valve seat;
A drive unit coupled to the main valve via a valve stem and driving the main valve;
A steam valve, wherein a pressing mechanism that presses the inner casing against the inner surface of the outer casing is interposed between the locking body and the inner casing. The pressing mechanism includes a locking plane that is locked to the locking body and a pressing surface that is formed on the inner casing side, and an annular rotation-side pressing member that is rotatable in the circumferential direction; An annular fixed-side pressing member that includes a pressure-receiving surface that is interposed between the rotating-side pressing member and the inner casing and is pressed against the pressing surface of the rotating-side pressing member;
The pressing surface of the rotation-side pressing member is inclined in the circumferential direction with respect to the locking plane, and the pressure receiving surface of the fixed-side pressing member is inclined in the circumferential direction so as to correspond to the pressing surface. ,
The steam valve according to claim 1, wherein the inner casing is pressed via the fixed-side pressing member by rotating the rotating-side pressing member in a circumferential direction. The rotation side pressing member is provided with a plurality of rotation side positioning holes penetrating in the axial direction,
The fixed-side pressing member is provided with a plurality of fixed-side positioning holes that are positioned substantially on the same circumference as the rotation-side positioning hole and penetrate in the axial direction.
The rotation-side pressing between the center of any one rotation-side positioning hole among the plurality of rotation-side positioning holes and the center of another rotation-side positioning hole adjacent to the one rotation-side positioning hole. The circumferential angle with respect to the center point of the member is such that the center of one fixed side positioning hole corresponding to the one rotation side positioning hole and the center of another fixed side positioning hole corresponding to the other rotation side positioning hole The steam valve according to claim 2, wherein circumferential angles with respect to a center point of the fixed-side pressing member are different from each other. On the pressing surface of the rotating side pressing member, a plurality of rotating side protrusions protruding toward the fixed side pressing member side are provided across the circumferential direction,
A plurality of fixed sides that engage with the rotation-side protrusions of the rotation-side pressing member on the pressure-receiving surface of the fixed-side pressing member and allow only rotation in one direction of the rotation-side pressing member The steam valve according to claim 2, wherein a protrusion is provided. The pressing mechanism includes an annular first pressing member including a locking plane locked to the locking body and a pressing surface formed on the inner casing side, and the first pressing member and the inner casing. An annular second pressing member interposed between and including a pressure receiving surface formed on the first pressing member side and a contact plane that contacts the inner casing;
The pressing surface of the first pressing member is inclined with respect to the locking plane so that the wall thickness decreases toward the inner peripheral side,
The pressure-receiving surface of the second pressing member is inclined with respect to the abutting plane so that the wall thickness decreases toward the inner peripheral side;
A first wedge surface corresponding to the pressing surface of the first pressing member and a second wedge surface corresponding to the pressure receiving surface of the second pressing member between the first pressing member and the second pressing member. And a wedge-shaped member including
The steam valve according to claim 1, wherein the inner casing is pressed via the second pressing member by pressing the wedge-shaped member toward the outer peripheral side. The inner casing has an annular abutting plane that abuts against the abutting plane of the second pressing member, and a bulge that protrudes closer to the wedge-shaped member than the abutting plane at the center side of the abutting plane. And
The steam valve according to claim 5, wherein a spacer is interposed between an inner peripheral end of the wedge-shaped member and the raised portion of the inner casing.

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