JP2011085185A - Steam valve device, and steam turbine power generation facility equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steam valve device for reducing a steam amount leaking from a clearance between a valve rod and a bush, and to provide steam turbine power generation facilities equipped therewith. <P>SOLUTION: The steam valve device 10 includes a steam valve body having a steam inlet portion and a steam output portion, and an upper lid 30 for closing an upper face opening portion of the steam valve body. A valve seat is provided to the steam outlet side. A valve element for abutting on the valve seat is provided at the front end of the valve rod 26 passing through the upper lid 30 and inserted inside the steam valve body. On a portion of the valve rod 26 passing through the upper lid 30, the bush 31 is provided at a predetermined clearance between the valve rod 26 and itself so that the valve rod 26 can be moved forward and backward in the axial direction. Peripherally over the inner face of the bush 31, an air flow generator 50 is provided for changing steam flowing into the clearance between the valve rod 26 and the bush 31 into a plasma form to generate an air flow in the clearance between the valve rod 26 and the bush 31. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a steam valve assembly, in particular with an airflow generating device, to color the steam valve assembly with reduced leakage amount of steam and steam turbine power plant equipped with it between the valve stem and the bushing.

  FIG. 9 is a diagram schematically illustrating an example of a configuration of a conventional steam turbine power generation facility.

  As shown in FIG. 9, the steam from the superheater 410 a of the boiler 410 passes through the main steam stop valve 401 and the steam control valve 402 and is introduced into the high-pressure turbine 420. The steam introduced into the high-pressure turbine 420 is expanded and then heated by the reheater 410b of the boiler 410 via the check valve 403. The steam heated by the reheater 410b of the boiler 410 is introduced into the intermediate pressure turbine 421 through the re-steam stop valve 404 and the intercept valve 405, and after being expanded, is introduced into the low pressure turbine 422. The steam introduced into the low-pressure turbine 422 performs expansion work, and is then returned to water by the condenser 423. The condensate in the condenser 423 is increased in pressure by the feed water pump 424 and guided again to the superheater 410 a of the boiler 410.

  Further, in order to increase the operation efficiency in the steam turbine power generation facility, depending on the steam turbine power generation facility, a high pressure provided in a flow path connecting the inflow side of the main steam stop valve 401 and the inflow side of the reheater 410b of the boiler 410. A low pressure turbine bypass valve 407 is installed in a flow path connected between the turbine bypass valve 406 and the outflow side of the reheater 410 b of the boiler 410 and the condenser 423. Thus, the boiler system can be circulated independently of the operation of the steam turbine.

  FIG. 10 is a view showing a cross section of the steam control valve 402 used in the conventional steam turbine power generation facility described above.

  As shown in FIG. 10, the steam control valve 402 includes a steam inlet 451 into which steam from a boiler or the like (not shown) flows, and steam that causes steam to flow out in a direction orthogonal to the direction in which steam flows in the steam inlet 451. A steam valve main body 450 having an outlet 452 and an upper lid 460 for closing the upper surface opening of the steam valve main body 450 are provided.

  Further, a valve seat 453 is provided on the steam outlet body side inside the steam valve main body 450. The valve body 470 that abuts on the valve seat 453 is attached to the tip of a valve rod 471 that passes through the upper lid 460 and is inserted into the steam valve main body 450. The valve rod 471 is connected to a hydraulic drive mechanism 480 supported by the upper lid 460. In this case, since the penetrating portion of the valve rod 471 in the upper lid 460 becomes a sliding surface, a bush 461 is provided in this portion.

  In the steam control valve 402 having such a structure, when the valve rod 471 is driven in the vertical direction by the hydraulic drive mechanism 480, the valve body 470 contacts or separates from the valve seat 453. By this contact or separation, the steam control valve 402 is opened and closed, and the rotation speed of the steam turbine is controlled by controlling the amount of steam flowing to the steam turbine.

  Here, in the above-described conventional steam control valve 402, the gap between the inner diameter of the bush 461 and the outer diameter of the valve rod 471, which is the sliding surface of the valve rod 471, is (1) the material of the valve rod 471 and the bush 461. Considering the heat expansion difference due to the combination, and (2) the amount of oxide scale adhering to the valve stem 471 and the bush 461 expected from the scheduled operation period, the dimensions are large enough not to impede the reciprocating motion of the valve stem 471. It has been decided. The gap dimension between the inner diameter of the bush 461 and the outer diameter of the valve stem 471 is set to approximately 1 mm or less. Therefore, in normal operation, steam always leaks from the steam chamber toward the atmosphere through the gap between the bush 461 and the valve rod 471.

  Furthermore, recently, the pressure and temperature of the steam introduced into the steam turbine have increased, and the size of the gap between the bush 461 and the valve stem 471 has been further expanded for the reasons (1) and (2) above. Must be designed. As a result, the amount of steam leakage from the gap between the bush 461 and the valve stem 471 tends to increase.

  In addition, there is a strong demand for improving the performance (efficiency) of the steam turbine power generation facility. Even in the steam valve installed at the inlet of the steam turbine, expansion work is performed in the steam turbine from the gap between the bush 461 and the valve rod 471. Leakage of a part of the steam before starting may cause a reduction in efficiency of the steam turbine power generation facility. Therefore, technical development for suppressing the leakage of steam from the gap between the bush 461 and the valve rod 471 in the steam valve has been performed (for example, see Patent Document 1).

Japanese Utility Model Publication No. 60-77703

  However, in the conventional steam leakage suppression technology, the oxide scale attached to the surface of the valve stem partially peels off, creating a step or gap between the valve stem base material and the remaining oxide scale, and Sometimes it became a passage. In addition, the oxide scale may adhere to the outer periphery of the valve stem or the inner periphery of the valve stem sleeve, thereby obstructing the reciprocation of the valve stem.

  The present invention has been made to solve the above problems, the steam turbine power plant including the same, and a steam valve apparatus can be reduced amount of steam leaking from the clearance between the valve stem and the bushing The purpose is to provide.

  In order to achieve the above object, according to one aspect of the present invention, a steam valve body having a steam inlet portion and a steam outlet portion, an upper lid for closing an upper surface opening of the steam valve body, and an atmosphere side of the upper lid a valve stem wherein the steam valve is provided by penetrating the steam chamber in the body, for controlling the flow rate of steam flowing from the steam outlet by the valve body having a tip portion from the through hole of the upper cover, wherein the valve rod penetrates and the bushing in which the valve rod is provided with a gap between the valve rod so as to be able to advance and retreat in the axial direction, a portion of the steam flowing in the gap between the valve rod and the bush There is provided a steam valve device comprising an airflow generating device that generates an induced airflow in a gap between the valve stem and the bush by being converted into plasma.

  Further, according to one aspect of the present invention, a steam valve main body having a steam inlet portion and a steam outlet portion, an upper lid that closes an upper surface opening of the steam valve main body, and an inside of the steam valve main body from the atmosphere side of the upper lid provided by penetration of the steam chamber, a valve stem for controlling the flow rate of steam flowing from the steam outlet by the valve body having a tip portion, the valve stem into the through hole of the upper cover, wherein the valve rod penetrates the shaft a bush which is provided with a gap between the valve rod so as to be able to advance and retreat in a direction, in the steam chamber side of the bushing, the valve stem is passed through so as to be moved forward and backward in an axial direction, An annular movable ring member provided between the valve stem and a gap narrower than the gap with the bush, and is movable in a direction orthogonal to the axial direction of the valve stem; and the valve stem And part of the steam flowing into the gap between the movable ring member and By plasma of steam valve device characterized by comprising a flow generator for generating an induced air flow in the gap between the movable ring member and the valve rod is provided.

  Furthermore, according to one aspect of the present invention, there is provided a steam turbine power generation facility comprising any one of the steam valve devices described above.

  According to the steam valve device of the present invention and the steam turbine power generation facility equipped with the steam valve device, the amount of steam leaking from the gap between the valve stem and the bush can be reduced.

It is a figure showing the section of the steam valve device of a 1st embodiment concerning the present invention. It is a figure which shows the cross section of the upper cover of the steam valve apparatus of 1st Embodiment which concerns on this invention. It is a perspective view which shows a part of bush provided in the penetration part of the upper cover in the steam valve apparatus of 1st Embodiment which concerns on this invention. It is a perspective view which shows a part of bush provided in the penetration part of an upper cover in the steam valve apparatus of 1st Embodiment which concerns on this invention, when an airflow generation apparatus is made into another arrangement configuration. It is a figure which shows the cross section of the steam valve apparatus of 2nd Embodiment which concerns on this invention. It is a perspective view which shows a part of bush provided in the penetration part of the upper cover in the steam valve apparatus of 2nd Embodiment which concerns on this invention. It is a figure which shows the cross section of the steam valve apparatus of 3rd Embodiment which concerns on this invention. It is a figure which shows the cross section of the steam valve apparatus of 4th Embodiment which concerns on this invention. It is the figure which showed typically an example of the structure of the conventional steam turbine power generation equipment. It is a figure which shows the cross section of the steam control valve currently used for the conventional steam turbine power generation equipment.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a view showing a cross section of a steam valve device 10 according to a first embodiment of the present invention.

  As shown in FIG. 1, the steam valve device 10 has a steam inlet portion 21 into which steam flows and a steam outlet portion 22 through which the steam flows out in a direction perpendicular to the direction in which the steam flows in the steam inlet portion 21. A valve body 20 and an upper lid 30 that closes the upper surface opening of the steam valve body 20 are provided.

  Further, a valve seat 24 is provided on the steam outlet side of the steam chamber 23 inside the steam valve body 20. The valve body 25 that abuts on the valve seat 24 is attached to the tip of a valve rod 26 that passes through the upper lid 30 and is inserted into the steam valve main body 20. The valve stem 26 is connected to a hydraulic drive mechanism 40 supported by the upper lid 30.

  A bush 31 is provided at a through-hole portion of the valve stem 26 in the upper lid 30 with a predetermined gap between the valve stem 26 and the valve stem 26 so that the valve stem 26 can advance and retreat in the axial direction. Further, a part of the steam flowing into the gap between the valve stem 26 and the bush 31 is formed into a plasma over the inner surface of the bush 31 to form a plasma, thereby forming a gap between the valve stem 26 and the bush 31. An airflow generation device 50 that generates an induced airflow (airflow F described later) is provided.

  Next, the structure of the penetration part of the upper cover 30 provided with the airflow generation device 50 will be described in detail.

  FIG. 2 is a view showing a cross section of the upper lid 30 of the steam valve device 10 according to the first embodiment of the present invention. FIG. 3 is a perspective view showing a part of the bush 31 provided in the penetrating portion of the upper lid 30 in the steam valve device 10 according to the first embodiment of the present invention.

  As shown in FIGS. 2 and 3, the airflow generation device 50 is provided in a circumferential shape across the inner surface of the bush 31. The airflow generation device 50 includes a pair of electrodes including a first electrode 51 and a second electrode 52, and a solid in which the first electrode 51 and the second electrode 52 are disposed with a predetermined interval. And a discharge power source 54 for applying a voltage between the first electrode 51 and the second electrode 52. The first electrode 51 and the second electrode 52 are connected to a discharge power source 54 via a cable 55.

  As shown in FIG. 3, the first electrode 51 and the second electrode 52 have a ring shape and are continuously provided in the circumferential direction. Further, the first electrode 51 and the second electrode 52 are arranged so as to be shifted in the axial direction of the valve stem 26 without directly contacting each other. That is, the first electrode 51 and the second electrode 52 are disposed so that the dielectric 53 is interposed between these electrodes. Further, the distance (L1) between the first electrode 51 and the second electrode 52 shown in FIG. 2 is shorter than the distance (gap distance) (L2) between the valve stem 26 and the bush 31. Has been. Thus, when a voltage is applied between the first electrode 51 and the second electrode 52, the first electrode 51 or the second electrode 52 and the valve rod 26 do not discharge, An appropriate dielectric barrier discharge occurs between the first electrode 51 and the second electrode 52.

  The first electrode 51 and the second electrode 52 are appropriately selected from known conductive materials according to the environment in which the airflow generation device 50 is used. As the first electrode 51 and the second electrode 52, for example, a copper plate or the like can be used. In addition, as the first electrode 51 and the second electrode 52, for example, stainless steel, Inconel (trade name), Hastelloy (trade name), titanium, platinum, tungsten, molybdenum, nickel, copper, gold, silver, chromium, etc. It can also be used according to the environment in which a metal, an alloy mainly containing these metal elements, an inorganic good conductor such as conductive ceramics, or the like is used.

  In particular, when a heat-resistant or corrosion-resistant metal such as Inconel, Hastelloy, or titanium is used for the conductor, it is possible to realize an electrode that can be used for a long time even in a high-corrosion atmosphere such as high temperature and high humidity and oxidation. it can.

  2 and 3, the dielectric 53 is fitted in a ring shape in a groove provided on the inner surface of the bush 31, and the surface of the dielectric 53 facing the valve rod 26 is the same as the inner surface of the bush 31. It is comprised so that it may become a surface. In addition, one surface of the first electrode 51 and the second electrode 52 is configured to be flush with the surface of the dielectric 53. For example, the first electrode 51 or the second electrode 52 may be configured to be embedded in the dielectric 53. Furthermore, both the first electrode 51 and the second electrode 52 may be configured to be embedded in the dielectric 53.

  The dielectric 53 is appropriately selected from known dielectric materials according to the environment in which the airflow generation device 50 is used. The dielectric 53 is made of a dielectric material such as a ceramic material mainly composed of aluminum nitride, alumina, zirconia, hafnia, titania, silica, or the like.

  The discharge power supply 54 functions as a voltage application mechanism and applies a voltage between the first electrode 51 and the second electrode 52. From the discharge power supply 54, for example, a pulsed output voltage that intermittently outputs positive and / or negative voltage, an alternating voltage that alternately outputs positive and negative pulsed voltage, and alternating current An output voltage or the like having a waveform of (sine wave, intermittent sine wave) is output. In addition, the discharge power supply 54 may apply a voltage between the first electrode 51 and the second electrode 52 while adjusting the voltage value, for example, by adjusting the output voltage to output the output voltage. Specifically, for example, when positive and negative voltages are alternately and intermittently output at a predetermined duty ratio, two pulses are set to a high output from the beginning, and the subsequent two pulses are set to a half of the output. For example, control of repeatedly applying a combination of two high-power pulses and half of the two power pulses. Note that the present invention is not limited to these, and the voltage control can be set as appropriate according to the use conditions and applications.

  Next, the operation of the steam valve device 10 of the first embodiment will be described.

  In the steam valve device 10, when the valve rod 26 is driven in the vertical direction by the hydraulic drive mechanism 40, the valve body 25 contacts or separates from the valve seat 24. When the valve body 25 contacts the valve seat 24, the steam valve device 10 is closed, and the introduction of steam into the steam turbine is shut off.

  On the other hand, when the valve body 25 is separated from the valve seat 24, the steam valve device 10 is opened, and steam is introduced into the steam turbine. At this time, the flow rate of the steam introduced into the steam turbine is controlled by driving the valve rod 26 by the hydraulic drive mechanism 40 and adjusting the valve opening degree.

  Further, when a voltage is applied between the first electrode 51 and the second electrode 52 from the discharge power supply 54 and a potential difference equal to or greater than a certain threshold value is reached, the voltage between the first electrode 51 and the second electrode 52 is reduced. Discharge occurs in A discharge plasma is generated along with this discharge. Here, since the dielectric 53 is interposed between the first electrode 51 and the second electrode 52, the dielectric barrier can be stably maintained without causing arc discharge even at high temperatures. Discharge occurs. The dielectric barrier discharge is a creeping discharge formed along the dielectric 53.

  Due to this dielectric barrier discharge, in the gap between the valve stem 26 and the bush 31, from the first electrode 51 side to the second electrode 52 side, or from the second electrode 52 side to the first electrode 51 side. An airflow F that flows toward it is generated. This air flow F is generated when a part of the leaked steam existing in the gap between the valve rod 26 and the bush 31 is turned into plasma. As described above, in the airflow generation device 50, the first electrode 51 side is changed to the second electrode 52 side, or the second electrode 52 side is changed to the first electrode 51 side, depending on the electrode arrangement configuration and the voltage application method. A flowing air flow F can be generated.

  Here, in order to reduce the leakage flow rate of the steam leaking from the gap between the valve stem 26 and the bush 31, it is preferable to generate the air flow F so that the leaking steam flows in the opposite direction. In this way, by making the direction of the airflow F opposite to the direction in which the leaking steam flows, both flows collide in the gap between the valve stem 26 and the bush 31 and the pressure loss in the gap increases. To do. Therefore, it becomes difficult for leaked steam to flow to the outside through the gap between the valve rod 26 and the bush 31, and the leak flow rate of the leaking steam can be reduced.

  In the dielectric barrier discharge as described above, when a DC voltage is applied between the first electrode 51 and the second electrode 52, charges accumulate on the surface of the dielectric 53 as the discharge progresses. As a result, the electric field between the first electrode 51 and the second electrode 52 is relaxed, and eventually the electric field cannot maintain the ionization of the space, and the discharge stops. In order to prevent this discharge from stopping, it is necessary to remove the electric charge stored on the surface of the dielectric 53. For this purpose, it is preferable to apply an alternating voltage or an alternating voltage, which is a pulsed positive / negative bipolar voltage, between the first electrode 51 and the second electrode 52. Thus, by applying an alternating voltage or an alternating voltage between the first electrode 51 and the second electrode 52, it is possible to perform a dielectric barrier discharge continuously.

  As described above, according to the steam valve device 10 of the first embodiment, the airflow generation device 50 is provided circumferentially over the inner surface of the bush 31, and the gap between the valve stem 26 and the bush 31 is provided. By generating the air flow F and disturbing the flow in the gap, it is possible to increase the pressure loss in the leaked steam flowing toward the outside through the gap. As a result, the leaked steam is difficult to flow outward through the gap between the valve stem 26 and the bush 31, and the leak flow rate of the leaking steam can be reduced. In this manner, the flow rate of the leaked steam can be reduced without providing a seal member or the like that is brought into contact with the valve rod 26 to reduce the flow rate of the leaked steam.

  Here, in the steam valve device 10 of the first embodiment described above, an example in which one airflow generation device 50 is provided circumferentially over the inner surface of the bush 31 is shown. A plurality of airflow generation devices 50 provided in a circumferential shape may be provided in the axial direction of the valve rod 26.

  In the steam valve device 10 of the first embodiment described above, an example in which the first electrode 51 and the second electrode 52 are ring-shaped has been shown. However, the first electrode 51 and the second electrode 52 A pair of electrodes composed of the electrodes 52 may be intermittently arranged by being divided into a plurality at predetermined intervals in the circumferential direction of the inner surface of the bush 31. Further, a plurality of airflow generation devices 50 that are intermittently arranged in the circumferential direction of the inner surface of the bush 31 may be provided in the axial direction of the valve stem 26. In this case, in order to generate the airflow F over the entire circumferential direction in a predetermined region of the gap between the valve stem 26 and the bush 31, the airflow generators 50 adjacent in the axial direction of the valve stem 26 are arranged in a staggered manner. It is preferable to do.

  Further, in the first embodiment steam valve assembly 10 described above, an example provided with an airflow generating device 50 circumferentially over the inner surface of the bush 31 is not limited to this arrangement. FIG. 4 shows a part of the bush 31 provided in the penetrating portion of the upper lid 30 in the steam valve device 10 according to the first embodiment of the present invention when the airflow generation device 50 has another arrangement configuration. FIG.

  As shown in FIG. 4, the airflow generation device 50 may be provided so that the first electrode 51 and the second electrode 52 are arranged in the direction along the axial direction of the valve rod 26 on the inner surface of the bush 31. Good. In this case, it is preferable to arrange the plurality of airflow generation devices 50 at a predetermined interval in the circumferential direction of the inner surface of the bush 31.

  In this case, the airflow F is generated in the circumferential direction. And the airflow F which goes to this circumferential direction, and the leaked steam which flows outside through a gap | interval collide, and are disturb | confused, and the pressure loss in the leaked steam which flows outside through a gap | interval increases. As a result, the leaked steam is difficult to flow outward through the gap between the valve stem 26 and the bush 31, and the leak flow rate of the leaking steam can be reduced.

(Second Embodiment)
The steam valve device 11 of the second embodiment according to the present invention has the same configuration except for the configurations of the steam valve device 10 and the airflow generation device 50 of the first embodiment. Therefore, here, the airflow generation device 50 having a configuration different from that of the steam valve device 10 of the first embodiment will be mainly described.

  FIG. 5 is a view showing a cross section of the steam valve device 11 according to the second embodiment of the present invention. FIG. 6 is a perspective view showing a part of the bush 31 provided in the penetrating portion of the upper lid 30 in the steam valve device 11 according to the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the component same as the steam valve apparatus 10 of 1st Embodiment, and the overlapping description is abbreviate | omitted or simplified.

  As shown in FIG. 5 and FIG. 6, the airflow generation device 50 includes a pair of a first electrode 51 provided circumferentially over the inner surface of the bush 31 and a second electrode 52 including the valve rod 26. A dielectric 56 composed of a gas interposed between the first electrode 51 and the second electrode 52, and a cable 55 between the first electrode 51 and the second electrode 52. And a discharge power supply 54 for applying a voltage.

  The first electrode 51 has a ring shape and is provided continuously in the circumferential direction. In addition, a gap between the valve stem 26 and the bush 31 is set so that the first electrode 51 and the second electrode 52 do not directly contact each other. Further, when a voltage is applied between the first electrode 51 and the second electrode 52 (valve rod 26) between the valve stem 26 and the bush 31, the first electrode 51 and the second electrode 51. The distance is set so as to generate an appropriate dielectric barrier discharge with respect to 52.

  The first electrode 51 is configured to be flush with the surface of the dielectric 57. For example, the first electrode 51 may be configured to be embedded in the dielectric 57. 5 and 6, the dielectric 57 is fitted in a ring shape in a groove provided on the inner surface of the bush 31, and the surface of the dielectric 57 facing the valve rod 26 is the inner surface of the bush 31. It is comprised so that it may become the same surface. The material constituting the dielectric 57 is made of the same material as the material constituting the dielectric 53 in the steam valve device 10 of the first embodiment described above, and the airflow generator 50 is used from these materials. It is appropriately selected according to the environment.

  The position in the axial direction on the inner surface of the bush 31 where the first electrode 51 is provided is not particularly limited, but as shown in FIG. 5, the valve rod is provided on the steam chamber 23 side, and leaked steam flows. It is preferable to increase the pressure loss in the upstream part of the gap between 26 and the bush 31.

  The valve stem 26 as the second electrode 52 is made of a conductive metal.

  The dielectric 56 interposed between the first electrode 51 and the second electrode 52 is composed of a gas such as leaked steam that flows into the gap between the valve stem 26 and the bush 31.

  Next, the operation of the steam valve device 11 of the second embodiment will be described.

  Here, the configuration of the steam valve device 11 other than that shown in FIGS. 5 and 6 will be described with reference to the configuration shown in FIG. 1.

  In the steam valve device 11, when the valve rod 26 is driven in the vertical direction by the hydraulic drive mechanism 40, the valve body 25 contacts or separates from the valve seat 24. When the valve body 25 contacts the valve seat 24, the steam valve device 10 is closed, and the introduction of steam into the steam turbine is shut off.

  On the other hand, when the valve body 25 is separated from the valve seat 24, the steam valve device 10 is opened, and steam is introduced into the steam turbine. At this time, the flow rate of the steam introduced into the steam turbine is controlled by driving the valve rod 26 by the hydraulic drive mechanism 40 and adjusting the valve opening degree.

  Further, when a voltage is applied between the first electrode 51 and the second electrode 52 (valve rod 26) from the discharge power supply 54 and a potential difference equal to or greater than a certain threshold value is reached, the first electrode 51 and the second electrode Dielectric barrier discharge occurs between the electrode 52 and the electrode 52. A discharge plasma is generated along with this discharge.

  By this dielectric barrier discharge, as shown in FIG. 6, in the gap between the valve stem 26 and the bush 31, from the first electrode 51 side to the second electrode 52 side, or from the second electrode 52 side. An airflow F flowing toward the first electrode 51 side is generated. This air flow F is generated when a part of the leaked steam existing in the gap between the valve rod 26 and the bush 31 is turned into plasma. As described above, in the airflow generation device 50, the first electrode 51 side is changed to the second electrode 52 side, or the second electrode 52 side is changed to the first electrode 51 side, depending on the electrode arrangement configuration and the voltage application method. A flowing air flow F can be generated.

  The air flow F generated in this way collides with leaked steam flowing outward through the gap between the valve stem 26 and the bush 31. This collision increases the pressure loss of the leaked steam flowing in the gap. Therefore, it becomes difficult for leaked steam to flow to the outside through the gap between the valve rod 26 and the bush 31, and the leak flow rate of the leaking steam can be reduced.

  As described above, according to the steam valve device 11 of the second embodiment, the air flow generation device 50 is provided to generate the air flow F in the gap between the valve rod 26 and the bush 31 and the flow in the gap. By disturbing, the pressure loss in the leaked steam flowing toward the outside through the gap can be increased. As a result, the leaked steam is difficult to flow outward through the gap between the valve stem 26 and the bush 31, and the leak flow rate of the leaking steam can be reduced. In this manner, the flow rate of the leaked steam can be reduced without providing a seal member or the like that is brought into contact with the valve rod 26 to reduce the flow rate of the leaked steam.

  Further, by substituting the valve rod 26 for the second electrode 52 in the airflow generation device 50, the components of the airflow generation device 50 provided in the bush 31 can be reduced, and the size and manufacturing cost can be reduced. be able to.

  Here, in the steam valve device 11 according to the second embodiment described above, an example in which one first electrode 51 is provided circumferentially over the inner surface of the bush 31 is shown. A plurality of first electrodes 51 provided in a circumferential shape may be provided in the axial direction of the valve stem 26.

  Further, in the steam valve device 11 of the second embodiment described above, an example in which the shape of the first electrode 51 is a ring shape has been shown, but the first electrode 51 is arranged in the circumferential direction of the inner surface of the bush 31. It may be arranged intermittently by being divided into a plurality at predetermined intervals. A plurality of first electrodes 51 that are intermittently arranged in the circumferential direction of the inner surface of the bush 31 may be provided in the axial direction of the valve stem 26. In this case, the first electrodes 51 adjacent in the axial direction of the valve stem 26 are staggered in order to generate the air flow F over the entire circumferential direction in a predetermined region of the gap between the valve stem 26 and the bush 31. It is preferable to arrange.

  Further, the first electrode 51 may be disposed on the inner surface of the bush 31 in a direction along the axial direction of the valve stem 26. In this case, it is preferable to arrange the plurality of first electrodes 51 at a predetermined interval in the circumferential direction of the inner surface of the bush 31.

(Third embodiment)
FIG. 7 is a view showing a cross section of the steam valve device 12 according to the third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the component same as the steam valve apparatus 10 of 1st Embodiment, and the overlapping description is abbreviate | omitted or simplified.

  As shown in FIG. 7, the steam valve device 12 according to the third embodiment of the present invention has a movable ring member that allows the valve rod 26 to pass through the steam chamber side from the bush 31 so that the valve rod 26 can advance and retreat in the axial direction. 70 and an airflow generation device 50 that generates an induced airflow (airflow F) in the gap between the movable ring member 70 and the valve stem 26.

  The movable ring member 70 has a projecting portion 71 projecting in a circumferential shape in the radial direction, and is configured by an annular member having a through-hole through which the valve rod 26 can advance and retreat in the axial direction. The movable ring member 70 is supported from below by a support member 80 so that the movable ring member 70 can move in a direction orthogonal to the axial direction of the valve stem 26. The support member 80 is fixed to the upper lid 30 by, for example, a plurality of bolts 90.

  Further, the gap between the valve stem 26 and the movable ring member 70 is configured to be narrower than the gap between the valve stem 26 and the bush 31.

  In a state where steam is not introduced into the steam valve device 12, one sliding surface 71 a of the projecting portion 71 is in contact with the sliding surface 81 of the support member 80. In order to allow the movable ring member 70 to move as described above, in this state, a slight gap is provided between the other sliding surface 71b of the projecting portion 71 and the end surfaces of the bush 31 and the upper lid 30 on the steam chamber side. It has been.

  On the other hand, in a state where steam is introduced into the steam valve device 12, the movable ring member 70 is pressed against the end surfaces of the bush 31 and the upper lid 30 on the steam chamber side by the pressure in the steam chamber of the steam valve device 12. There is a slight gap between the sliding surface 81 and one sliding surface 71a of the protrusion 71.

  The airflow generation device 50 is provided in a circumferential shape over the inner surface of the movable ring member 70. The airflow generation device 50 has the same configuration as the airflow generation device 50 in the steam valve device 10 of the first embodiment, and a pair of electrodes including a first electrode 51 and a second electrode 52, and Discharge in which a voltage is applied between the first electrode 51 and the second electrode 52, and the dielectric 53 made of a solid in which the first electrode 51 and the second electrode 52 are disposed at a predetermined interval. Power supply 54. The first electrode 51 and the second electrode 52 are connected to a discharge power source 54 via a cable 55.

  The first electrode 51 and the second electrode 52 have a ring shape and are continuously provided in the circumferential direction. Further, the first electrode 51 and the second electrode 52 are arranged so as to be shifted in the axial direction of the valve stem 26 without directly contacting each other. That is, the first electrode 51 and the second electrode 52 are disposed so that the dielectric 53 is interposed between these electrodes. Further, the distance (L1) between the first electrode 51 and the second electrode 52 shown in FIG. 7 is larger than the distance (gap distance) (L3) between the valve stem 26 and the movable ring member 70. It is structured short. Thus, when a voltage is applied between the first electrode 51 and the second electrode 52, the first electrode 51 or the second electrode 52 and the valve rod 26 do not discharge, An appropriate dielectric barrier discharge occurs between the first electrode 51 and the second electrode 52.

  The surfaces of the first electrode 51 and the second electrode 52 on the valve rod 26 side are covered with a dielectric 53. As a result, the first electrode 51 and the second electrode 52 can be prevented from coming into direct contact with the valve stem 26. Further, the surfaces of the first electrode 51 and the second electrode 52 covered with the dielectric 53 are configured to be flush with the inner surface of the movable ring member 70. Note that the surfaces of the first electrode 51 and the second electrode 52 covered with the dielectric 53 may be configured to protrude from the inner surface of the movable ring member 70.

  Next, the operation of the steam valve device 12 of the third embodiment will be described.

  Here, the configuration of the steam valve device 12 other than that shown in FIG. 7 will be described with reference to the configuration shown in FIG.

  In the steam valve device 12, when the valve rod 26 is driven in the vertical direction by the hydraulic drive mechanism 40, the valve body 25 contacts or separates from the valve seat 24. When the valve body 25 contacts the valve seat 24, the steam valve device 10 is closed, and the introduction of steam into the steam turbine is shut off.

  On the other hand, when the valve body 25 is separated from the valve seat 24, the steam valve device 10 is opened, and steam is introduced into the steam turbine. At this time, the flow rate of the steam introduced into the steam turbine is controlled by driving the valve rod 26 by the hydraulic drive mechanism 40 and adjusting the valve opening degree. In this case, the movable ring member 70 is pressed against the end surfaces on the steam chamber side of the bush 31 and the upper lid 30, and there is a slight gap between the sliding surface 81 of the support member 80 and one sliding surface 71 a of the protruding portion 71. it can.

  Further, when a voltage is applied between the first electrode 51 and the second electrode 52 from the discharge power supply 54 and a potential difference equal to or greater than a certain threshold value is reached, the voltage between the first electrode 51 and the second electrode 52 is reduced. Discharge occurs. A discharge plasma is generated along with this discharge. Here, since the dielectric 53 is interposed between the first electrode 51 and the second electrode 52, the dielectric barrier can be stably maintained without causing arc discharge even at high temperatures. Discharge occurs. The dielectric barrier discharge is a creeping discharge formed along the dielectric 53.

  By this dielectric barrier discharge, in the gap between the valve stem 26 and the movable ring member 70, the first electrode 51 side to the second electrode 52 side or the second electrode 52 side to the first electrode 51. An airflow F flowing toward the side is generated. This air flow F is generated when a part of the leaked steam existing in the gap between the valve stem 26 and the movable ring member 70 is turned into plasma. As described above, in the airflow generation device 50, the first electrode 51 side is changed to the second electrode 52 side, or the second electrode 52 side is changed to the first electrode 51 side, depending on the electrode arrangement configuration and the voltage application method. A flowing air flow F can be generated.

  Here, in order to reduce the flow rate of the leaked steam flowing in the gap between the valve stem 26 and the movable ring member 70, it is preferable to generate the air flow F so as to be opposite to the direction in which the leaking steam flows. Thus, by making the direction of the air flow F opposite to the direction in which the leaking steam flows, both flows collide in the gap between the valve stem 26 and the movable ring member 70, and the pressure loss in the gap Will increase. Therefore, it becomes difficult for leaked steam to flow to the outside through the gap between the valve rod 26 and the movable ring member 70, and the leakage flow rate of the leaked steam can be reduced.

  In addition, since the movable ring member 70 is configured to move in a direction orthogonal to the axial direction of the valve stem 26, even when the valve stem 26 swings, a predetermined gap is maintained from the valve stem 26. The movement of the valve stem 26 is followed.

  As described above, according to the steam valve device 12 of the third embodiment, the movable ring member 70 is provided, the airflow generator 50 is provided circumferentially over the inner surface of the movable ring member 70, and the valve rod 26. By generating an air flow F in the gap between the movable ring member 70 and disturbing the flow in the gap, it is possible to increase the pressure loss in the leaked steam flowing toward the outside through the gap. As a result, the leaked steam becomes difficult to flow outward through the gap between the valve stem 26 and the movable ring member 70, and the leaking flow rate of the leaking steam can be reduced.

  Further, by configuring the gap between the valve stem 26 and the movable ring member 70 to be narrower than the gap between the valve stem 26 and the bush 31, the valve stem 26 and the movable ring member 70, which are the inlet portions of leaked steam, are formed. The pressure loss of the leaked steam in the gap can be increased. Thereby, the leakage flow rate of the leaking steam can be reduced. In this manner, the flow rate of the leaked steam can be reduced without providing a seal member or the like that is brought into contact with the valve rod 26 to reduce the flow rate of the leaked steam.

  Further, since the surfaces of the first electrode 51 and the second electrode 52 on the side of the valve rod 26 are covered with the dielectric 53, the first electrode 51 and the second electrode 52 even when the valve rod 26 swings. The electrode 52 can be prevented from coming into direct contact with the valve stem 26.

  Here, in the third embodiment of the steam valve assembly 12 described above, an example with one of the airflow generating device 50 over the inner surface of the movable ring member 70 circumferentially, the movable ring member 70 A plurality of airflow generation devices 50 provided circumferentially over the inner surface of the valve rod 26 may be provided in the axial direction of the valve rod 26.

  In the steam valve device 12 according to the third embodiment described above, an example in which the first electrode 51 and the second electrode 52 are ring-shaped has been shown. However, the first electrode 51 and the second electrode 52 The pair of electrodes formed of the electrodes 52 may be intermittently arranged by being divided into a plurality at predetermined intervals in the circumferential direction of the inner surface of the movable ring member 70. Further, a plurality of airflow generation devices 50 that are intermittently arranged in the circumferential direction of the inner surface of the movable ring member 70 may be provided in the axial direction of the valve rod 26. In this case, in order to generate the airflow F over the entire circumferential direction in a predetermined region of the gap between the valve stem 26 and the movable ring member 70, the airflow generating device 50 that are adjacent to each other in the axial direction of the valve stem 26 A staggered arrangement is preferred.

  Further, the airflow generation device 50 may be provided so that the first electrode 51 and the second electrode 52 are arranged in the direction along the axial direction of the valve rod 26 on the inner surface of the movable ring member 70. In this case, it is preferable to arrange the plurality of airflow generation devices 50 at a predetermined interval in the circumferential direction of the inner surface of the movable ring member 70.

(Fourth embodiment)
The steam valve device 13 of the fourth embodiment according to the present invention has the same configuration except for the configurations of the steam valve device 12 and the airflow generation device 50 of the third embodiment. Therefore, here, the airflow generation device 50 having a configuration different from that of the steam valve device 12 of the third embodiment will be mainly described.

  FIG. 8 is a view showing a cross section of the steam valve device 13 according to the fourth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the component same as the steam valve apparatus 12 of 3rd Embodiment, and the overlapping description is abbreviate | omitted or simplified.

  The airflow generation device 50 includes a first electrode 51 that is provided circumferentially over the inner surface of the movable ring member 70, a pair of electrodes that include a second electrode 52 that includes a valve rod 26, and a first electrode A discharge power source that applies a voltage via a cable 55 between the first electrode 51 and the second electrode 52, and a dielectric 56 composed of a gas interposed between the first electrode 51 and the second electrode 52 54.

  The first electrode 51 has a ring shape and is provided continuously in the circumferential direction. In addition, since the surface of the first electrode 51 on the valve stem 26 side is covered with the dielectric 57, the first electrode 51 is in direct contact with the valve stem 26 even when the valve stem 26 swings. This can be prevented.

  Further, between the valve rod 26 and the movable ring member 70, when a voltage is applied between the first electrode 51 and the second electrode 52 (valve rod 26), the first electrode 51 and the second ring member 70 are connected to each other. The distance is set such that an appropriate dielectric barrier discharge occurs between the electrode 52 and the electrode 52.

  The surface of the first electrode 51 covered with the dielectric 57 is configured to be flush with the inner surface of the movable ring member 70. Note that the surface of the first electrode 51 covered with the dielectric 57 may protrude from the inner surface of the movable ring member 70.

  The dielectric 57 is fitted in a ring shape in a groove provided on the inner surface of the movable ring member 70 so that the surface of the dielectric 57 facing the valve rod 26 is flush with the inner surface of the movable ring member 70. It is configured. The material constituting the dielectric 57 is made of the same material as the material constituting the dielectric 53 in the steam valve device 10 of the first embodiment described above, and the airflow generator 50 is used from these materials. It is appropriately selected according to the environment.

  The position in the axial direction on the inner surface of the movable ring member 70 on which the first electrode 51 is provided is not particularly limited, but as shown in FIG. It is preferable to increase the pressure loss in the upstream portion of the gap between the valve stem 26 and the movable ring member 70.

  Further, the gap between the valve stem 26 and the movable ring member 70 is configured to be narrower than the gap between the valve stem 26 and the bush 31.

  The valve stem 26 as the second electrode 52 is made of a conductive metal.

  The dielectric 56 interposed between the first electrode 51 and the second electrode 52 is made of a gas such as leaked steam that flows into the gap between the valve rod 26 and the movable ring member 70.

  Next, the operation of the steam valve device 13 according to the fourth embodiment will be described.

  Here, the configuration of the steam valve device 13 other than that shown in FIG. 8 will be described with reference to the configuration shown in FIG.

  In the steam valve device 13, when the valve rod 26 is driven in the vertical direction by the hydraulic drive mechanism 40, the valve body 25 contacts or separates from the valve seat 24. When the valve body 25 contacts the valve seat 24, the steam valve device 10 is closed, and the introduction of steam into the steam turbine is shut off.

  On the other hand, when the valve body 25 is separated from the valve seat 24, the steam valve device 10 is opened, and steam is introduced into the steam turbine. At this time, the flow rate of the steam introduced into the steam turbine is controlled by driving the valve rod 26 by the hydraulic drive mechanism 40 and adjusting the valve opening degree. In this case, the movable ring member 70 is pressed against the end surfaces on the steam chamber side of the bush 31 and the upper lid 30, and there is a slight gap between the sliding surface 81 of the support member 80 and one sliding surface 71 a of the protruding portion 71. it can.

  Further, when a voltage is applied between the first electrode 51 and the second electrode 52 (valve rod 26) from the discharge power supply 54 and a potential difference equal to or greater than a certain threshold value is reached, the first electrode 51 and the second electrode Dielectric barrier discharge occurs between the electrode 52 and the electrode 52. A discharge plasma is generated along with this discharge.

  By this dielectric barrier discharge, in the gap between the valve stem 26 and the movable ring member 70, the first electrode 51 side to the second electrode 52 side or the second electrode 52 side to the first electrode 51. An airflow F flowing toward the side is generated. This air flow F is generated when a part of the leaked steam existing in the gap between the valve stem 26 and the movable ring member 70 is turned into plasma. As described above, in the airflow generation device 50, the first electrode 51 side is changed to the second electrode 52 side, or the second electrode 52 side is changed to the first electrode 51 side, depending on the electrode arrangement configuration and the voltage application method. A flowing air flow F can be generated.

  The airflow F generated in this manner collides with leaked steam flowing toward the outside through the gap between the valve rod 26 and the movable ring member 70. This collision increases the pressure loss of the leaked steam flowing in the gap. Therefore, it becomes difficult for leaked steam to flow to the outside through the gap between the valve rod 26 and the movable ring member 70, and the leakage flow rate of the leaked steam can be reduced.

  As described above, according to the steam valve device 13 of the fourth embodiment, the air flow generation device 50 is provided to generate the air flow F in the gap between the valve rod 26 and the movable ring member 70, and By disturbing the flow at, the pressure loss in the leaking steam flowing outward through the gap can be increased. As a result, the leaked steam becomes difficult to flow outward through the gap between the valve stem 26 and the movable ring member 70, and the leaking flow rate of the leaking steam can be reduced. In this manner, the flow rate of the leaked steam can be reduced without providing a seal member or the like that is brought into contact with the valve rod 26 to reduce the flow rate of the leaked steam.

  Further, by substituting the valve rod 26 for the second electrode 52 in the airflow generation device 50, the constituent members of the airflow generation device 50 provided in the movable ring member 70 can be reduced, and the size and manufacturing cost can be reduced. Can be achieved.

  Further, by configuring the gap between the valve stem 26 and the movable ring member 70 to be narrower than the gap between the valve stem 26 and the bush 31, the valve stem 26 and the movable ring member 70, which are the inlet portions of leaked steam, are formed. The pressure loss of the leaked steam in the gap can be increased. Thereby, the leakage flow rate of the leaking steam can be reduced.

  In addition, since the surface of the first electrode 51 on the valve stem 26 side is covered with the dielectric 57, the first electrode 51 is in direct contact with the valve stem 26 even when the valve stem 26 swings. This can be prevented.

  Here, in the steam valve device 13 of the above-described fourth embodiment, an example in which one first electrode 51 is provided circumferentially over the inner surface of the movable ring member 70 is shown. A plurality of first electrodes 51 provided circumferentially over the inner surface of 70 may be provided in the axial direction of the valve stem 26.

  Further, in the steam valve device 13 of the fourth embodiment described above, an example in which the shape of the first electrode 51 is a ring shape has been shown. However, the first electrode 51 is formed around the inner surface of the movable ring member 70. It may be arranged intermittently with a predetermined interval in the direction. Further, a plurality of first electrodes 51 that are intermittently arranged in the circumferential direction of the inner surface of the movable ring member 70 may be provided in the axial direction of the valve rod 26. In this case, in order to generate the air flow F over the entire circumferential direction in a predetermined region of the gap between the valve stem 26 and the movable ring member 70, the first electrode 51 adjacent in the axial direction of the valve stem 26. Are preferably arranged in a staggered manner.

  Further, the first electrode 51 may be disposed on the inner surface of the movable ring member 70 in a direction along the axial direction of the valve stem 26. In this case, it is preferable to arrange the plurality of first electrodes 51 at predetermined intervals in the circumferential direction of the inner surface of the movable ring member 70.

  Although the present invention has been specifically described above with reference to the embodiments, the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the invention. The steam valve device described above can be applied to various steam valves, such as a main steam stop valve, a steam control valve, a re-steam stop valve, and an intercept valve, which are provided in a steam turbine power generation facility as shown in FIG. it can.

  DESCRIPTION OF SYMBOLS 10, 11, 12, 13 ... Steam valve apparatus, 20 ... Steam valve main body, 21 ... Steam inlet part, 22 ... Steam outlet part, 23 ... Steam chamber, 24 ... Valve seat, 25 ... Valve body, 26 ... Valve rod, DESCRIPTION OF SYMBOLS 30 ... Upper cover, 31 ... Bush, 40 ... Hydraulic drive mechanism, 50 ... Airflow generator, 51 ... 1st electrode, 52 ... 2nd electrode, 53, 56, 57 ... Dielectric, 54 ... Power supply for discharge, 55 DESCRIPTION OF SYMBOLS ... Cable, 70 ... Movable ring member, 71 ... Projection part, 71a, 71b, 81 ... Sliding surface, 80 ... Support member, 90 ... Bolt, F ... Airflow.

Claims (13)

A steam valve body having a steam inlet and a steam outlet;
An upper lid for closing the upper surface opening of the steam valve body;
A valve rod that is provided by penetrating from the atmosphere side of the upper lid to the steam chamber in the steam valve main body, and controls the flow rate of the steam flowing out from the steam outlet by the valve body at the tip;
A bush provided with a gap between the valve stem so that the valve stem can advance and retreat in the axial direction in a through hole of the upper lid through which the valve stem passes;
An airflow generator for generating an induced airflow in the gap between the valve stem and the bush by converting a part of the steam flowing into the gap between the valve stem and the bush into plasma. A steam valve device characterized by.   The steam valve according to claim 1, wherein the airflow generation device includes a pair of electrodes, a dielectric interposed between the electrodes, and a voltage application mechanism capable of applying a voltage between the electrodes. apparatus. The pair of electrodes is composed of a first electrode and a second electrode provided on the inner surface of the bush,
The steam valve device according to claim 2, wherein the dielectric is made of a dielectric material made of a solid interposed between the first electrode and the second electrode.   The steam valve device according to any one of claims 1 to 3, wherein the air flow generation device is provided continuously or intermittently over the circumferential direction of the inner surface of the bush.   The steam valve device according to any one of claims 1 to 4, wherein a plurality of the airflow generation devices are provided in an axial direction of an inner surface of the bush. The pair of electrodes is composed of a first electrode provided on the inner surface of the bush and a second electrode made of the valve rod,
The steam valve device according to claim 2, wherein the dielectric is made of a gas interposed between the first electrode and the second electrode. A steam valve body having a steam inlet and a steam outlet;
An upper lid for closing the upper surface opening of the steam valve body;
A valve rod that is provided by penetrating from the atmosphere side of the upper lid to the steam chamber in the steam valve main body, and controls the flow rate of the steam flowing out from the steam outlet by the valve body at the tip;
A bush provided with a gap between the valve stem so that the valve stem can advance and retreat in the axial direction in a through hole of the upper lid through which the valve stem passes;
The valve rod is penetrated to the steam chamber side from the bush so as to be able to advance and retreat in the axial direction, and has a gap narrower than the gap with the bush between the valve rod and the valve rod. An annular movable ring member provided so as to be movable in a direction orthogonal to the axial direction;
An airflow generator for generating an induced airflow in the gap between the valve stem and the movable ring member by converting a part of the steam flowing into the gap between the valve stem and the movable ring member into plasma, and A steam valve device comprising:   The airflow generating device includes a pair of electrodes in which at least one of the electrodes has a surface covered with a covering dielectric, a dielectric interposed between the electrodes, and a voltage applying mechanism capable of applying a voltage between the electrodes The steam valve device according to claim 7, comprising: The pair of electrodes is provided on the inner surface of the movable ring member, and the surface is covered with the covering dielectric, and the first electrode and the second electrode are configured,
The steam valve device according to claim 8, wherein the dielectric is made of a dielectric material made of a solid interposed between the first electrode and the second electrode.   The steam valve device according to any one of claims 7 to 9, wherein the air flow generation device is provided continuously or intermittently over the circumferential direction of the inner surface of the movable ring member.   The steam valve device according to any one of claims 7 to 10, wherein a plurality of the airflow generation devices are provided in the axial direction of the inner surface of the movable ring member. The pair of electrodes is provided on the inner surface of the movable ring member, and a first electrode whose surface is covered with the covering dielectric, and a second electrode composed of the valve rod,
The steam valve device according to claim 8, wherein the dielectric is made of a gas interposed between the first electrode and the second electrode.   A steam turbine power generation facility comprising the steam valve device according to any one of claims 1 to 12.

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