JP2018112096A - Steam valve, steam turbine system including the same, and operation method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam valve which can prevent contact between a valve rod surface and a deformation portion even if a seal portion is deformed.SOLUTION: A steam valve includes: a valve rod 12 extending in a vertical direction; a bushing 14 which forms a cylindrical shape and supports the valve rod 12 disposed therein so that the valve rod 12 can slide in the vertical direction; and a connector lower part 18 which forms a cylindrical shape, is disposed with a lower end facing an upper end of the bushing 14, and moves with the valve rod 12 in the vertical direction. Inner peripheral surfaces 14a, 18a of the bushing 14 and the connector lower part 18 have a gap 27 between themselves and an outer peripheral surface 12a of the valve rod 12. A bushing step part 15 is formed at an upper end part of the bushing 14, and a connector step part 19 is formed at a lower end part of the connector 16.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a steam valve, a steam turbine system including a steam valve, and a method for operating the steam valve.

  The steam turbine is provided with a valve such as a steam flow rate adjusting valve that adjusts the flow rate of the steam that flows into the steam turbine, and a steam cutoff valve that blocks or allows the inflow of steam to the steam turbine. Since the steam to the steam turbine is high temperature and high pressure, such a valve needs to be reliable for opening and closing operation, and in order not to reduce the flow rate of the steam flowing into the steam turbine, A mechanism that prevents leakage to the outside may be provided. For example, Patent Document 1 discloses such a mechanism.

  In Patent Document 1, convex portions that swell in a direction in contact with each other are formed in positions that cover the periphery of the stop valve side valve shaft in each of the stop valve side valve body and the bush, and these convex portions are brought into surface contact with each other. Thus, the surface pressure is increased and the sealing performance of the stop valve side valve body, the bush and the surface contact portion is improved.

JP 2003-27904 A

  However, in the configuration described in Patent Document 1, since the portion where the convex portions are in surface contact is close to the stop valve side valve shaft located on the inner peripheral side, the surface pressure increases more than expected, In the case of deterioration over time, the surface contact portion may be deformed. When the surface contact portion is deformed, the deformed portion and the stop valve side valve shaft come into contact with each other, the surface of the stop valve side valve shaft is damaged, or the deformed portion adheres to the stop valve side valve shaft. If caught, the smooth movement of the valve stem may be affected. In addition, damage to the surface of the stop valve side valve shaft increases the amount of steam leaking to the outside, which may affect performance degradation.

The present invention has been made in view of such circumstances, and prevents contact between the valve stem surface and the deformed portion even when the seal portion of the support member that slidably supports the valve stem is deformed. An object of the present invention is to provide a steam valve capable of performing the above, a steam turbine system including the steam valve, and a method of operating the steam valve.
Also provided are a steam valve, a steam turbine system provided with a steam valve, and a steam valve operating method capable of preventing an increase in the amount of steam leakage due to contact between the outer peripheral surface of the valve stem and the deformed portion. For the purpose.

In order to solve the above problems, the steam valve, the steam turbine system provided with the steam valve, and the operation method of the steam valve of the present invention employ the following means.
A steam valve according to one aspect of the present invention has a valve body that contacts and separates from a valve seat, a valve rod that has one end connected to the valve body and extends in one direction, and has a cylindrical shape and is disposed inside. A bushing that slidably supports the valve stem in the one direction, a connector that has a cylindrical shape, one end portion of which is opposed to one end portion of the bushing, and moves in the one direction together with the valve rod; A moving means for moving the valve stem in the one direction, and the moving means moves the one end of the connector to the one end of the bushing when the valve body is in close contact with the valve seat. The inner peripheral surfaces of the bushing and the connector are spaced apart from the outer peripheral surface of the valve stem, and at least one of the one end portion of the bushing and the one end portion of the connector. The inner peripheral surface of the valve stem is separated from the outer peripheral surface of the valve stem. Distance is longer than the inner circumferential surface of a portion other than the end portion.

  The moving means moves the connector that moves together with the valve stem to contact the connector, thereby preventing vapor from leaking between the bushing and the connector. If the pressing force continues to act from the moving means during the contact between the bushing and the connector, the load continues to act on the portion where the bushing contacts the connector. At this time, the portion where the bushing and the connector come into contact with each other may be deformed so as to bulge toward the outer peripheral surface of the valve stem due to the load. Even in such a case, in the above configuration, the inner peripheral surface of at least one of the one end portion of the bushing and the one end portion of the connector is separated from the outer peripheral surface of the other portion with respect to the distance from the outer peripheral surface of the valve stem. Therefore, even if a deformed part occurs, it is difficult to contact the valve stem. Therefore, it is possible to prevent damage to the outer peripheral surface of the valve stem and sticking of the deformed portion to the outer peripheral surface of the valve stem, which are caused by the contact between the deformed portion of the bushing and the connector and the outer peripheral surface of the valve stem. In addition, an increase in the amount of steam leakage due to damage to the outer peripheral surface of the valve stem can be prevented.

  In the steam valve according to one aspect of the present invention, an oxide scale adhesion preventing material may be provided on the upper surface of the bushing.

  In the above configuration, since the oxide scale adhesion preventing material is provided in the portion that contacts the bushing connector, the oxide scale is hardly generated and adhered to the portion that contacts the bushing connector. Thereby, when a bushing and a connector contact, it can be made to contact without interposing a foreign material, and a bushing and a connector can be stuck closely. Therefore, it is possible to suppress the leakage of steam from the contacting portion.

  Moreover, the steam valve which concerns on 1 aspect of this invention may be provided with the oxide scale adhesion prevention material in the internal peripheral surface which faces the said valve rod of the said bushing.

  In the above configuration, since the oxide scale adhesion preventing material is provided on the inner peripheral surface of the bushing, the oxide scale is not easily generated and adhered to the inner peripheral surface of the bushing. Therefore, it is possible to prevent the deterioration of the slidability to the moving operation of the valve stem and the damage to the outer peripheral surface of the valve stem, which are caused by the adhesion of oxide scale to the inner peripheral surface of the bushing.

  The steam valve according to an aspect of the present invention is provided on the outer peripheral side of the one end of the bushing and the one end of the connector so as to surround the one end of the bushing and the one end of the connector. You may provide the leak pipe and the temperature measurement means provided in the said leak pipe.

  In the above configuration, when the steam leaks from the portion where the bushing and the connector are in contact, the leaked steam flows through the leak pipe. When steam flows through the leak pipe, the temperature inside the leak pipe changes. Therefore, by measuring the temperature inside the leak pipe, it is possible to grasp the leak at an early stage when the steam starts leaking from the contact portion.

  Moreover, the steam turbine system which concerns on 1 aspect of this invention is equipped with the above steam valves, and the steam turbine from which steam is guide | induced from this steam valve.

  The steam valve operating method according to an aspect of the present invention includes a valve body that contacts and separates from a valve seat, a valve rod that has one end connected to the valve body and extends in one direction, and a tubular shape. A bushing that slidably supports the valve rod disposed therein in one direction, and has a cylindrical shape, and one end portion is disposed to face one end portion of the bushing, and the one direction together with the valve rod And a moving means for moving the valve stem in the one direction, and the moving means moves the bushing against the one end of the connector when the valve body is in close contact with the valve seat. The bushing and the inner peripheral surface of the connector are spaced apart from the outer peripheral surface of the valve stem, the one end portion of the bushing and the one end portion of the connector, The inner peripheral surface of at least one of A steam valve that is longer than an inner peripheral surface of a portion other than the one end with respect to a distance away from the outer peripheral surface of the valve stem, and the one end of the bushing is in contact with the valve body and the valve seat. And a step of bringing the one end portion of the connector into contact with the one end portion of the connector, and a step of separating the one end portion of the bushing from the one end portion of the connector when the valve body and the valve seat are separated from each other. Yes.

  According to the present invention, even if the seal portion of the support member that slidably supports the valve stem is deformed, contact between the deformed portion and the outer peripheral surface of the valve stem can be prevented. Further, it is possible to prevent an increase in the amount of steam leakage due to the contact between the deformed portion and the outer peripheral surface of the valve stem.

It is a longitudinal section showing a steam valve concerning an embodiment of the present invention. It is a longitudinal cross-sectional view which shows the principal part of the steam valve of FIG. It is a typical perspective view which shows the bushing and valve stem of the steam valve of FIG. It is a typical longitudinal cross-sectional view which shows the modification of the principal part of the steam valve of FIG. It is a graph which shows the time-dependent change condition of the temperature measurement value of a stem leak pipe.

Hereinafter, an embodiment of a steam valve, a steam turbine system provided with a steam valve, and a steam valve operating method according to the present invention will be described with reference to FIGS. 1 to 5.
As shown in FIG. 1, a steam flow rate adjusting valve (steam valve) 1 according to this embodiment is provided in a steam turbine system 30 and includes a valve mechanism 2 for adjusting the flow rate of steam flowing into a steam turbine (not shown). A casing 4 that houses the lower part of the valve mechanism 2 and forms the valve chamber 3 and a moving device (moving means) 5 that reciprocates the valve mechanism 2 in the vertical vertical direction. The casing 4 includes a casing body 4a and a lid body 8 that is fastened to the casing body 4a by bolts 20 and fixed. Further, the casing body 4a forms a steam inlet pipe 6 for allowing steam to flow into the valve chamber 3, and a steam outlet pipe 7 for supplying steam from the valve chamber 3 to the steam turbine.

  The valve mechanism 2 includes a valve rod 12 that extends in the vertical vertical direction and fixes the valve body 9 at the lower end portion, a connecting rod 13 that extends in the vertical vertical direction to connect the valve rod 12 and the moving device 5, and a lid 8. A bushing 14 which is fixed to the bushing 14 so as to be slidable in the vertical vertical direction, a connector 16 which is located above the bushing 14 and moves in the vertical vertical direction together with the valve rod 12, and a tubular shape which extends in the vertical vertical direction. A stem leak pipe (leak pipe) 21 provided on the upper end portion of the bushing 14 and the outer peripheral side of the connector 16 so as to surround the upper end portion of the bushing 14 and the connector 16 is provided.

  The valve body 9 includes a seating portion 10 that contacts and separates from the valve seat 22 and a fixing portion 11 that is fixed to the valve rod 12 above the seating portion 10. The valve body 9 is moved vertically in the vertical direction by the driving force of the moving device 5, and the seat portion 10 contacts the valve seat 22 located below the valve body 9, thereby shutting off the supply of steam to the steam turbine. A state (hereinafter, a state in which the seat portion 10 and the valve seat 22 are in contact with each other and the supply of steam to the steam turbine is cut off is referred to as a “closed state”), and the seat portion is moved vertically upward from the closed state. 10 and the valve seat 22 are separated from each other so that steam can be supplied to the steam turbine (hereinafter, the seating portion 10 and the valve seat 22 are separated from each other so that steam can be supplied to the steam turbine. "Open state"). In the open state, steam flows in the A direction from the steam inlet pipe 6 and the steam flows out from the steam outlet pipe 7 in the B direction.

  As shown in FIGS. 2 and 3, the valve stem 12 has a cylindrical shape, and the outer peripheral surface 12a is subjected to, for example, nitriding treatment in the present embodiment. The valve stem 12 is moved in the vertical vertical direction by the driving force from the moving device 5 (see FIG. 1), and the valve body 9 is closed or opened.

  As shown in FIGS. 2 and 3, the bushing 14 has a cylindrical shape extending vertically, and the valve rod 12 is inserted through the bushing 14. The bushing 14 includes an inner peripheral surface 14a that is spaced from and opposed to the outer peripheral surface 12a of the valve stem 12, and an upper surface 14b that extends substantially horizontally outward from the upper end of the inner peripheral surface 14a. That is, a gap 27 is formed between the inner peripheral surface 14a of the bushing 14 and the outer peripheral surface 12a of the valve stem 12 so that the valve stem 12 can move in the vertical vertical direction. The inner peripheral surface 14a and the upper surface 14b of the bushing 14 are preferably provided with wear / corrosion resistant materials in order to prevent the generation and adhesion of foreign matters such as oxide scales. In the present embodiment, for example, a built-up portion 14c formed by spraying a wear / corrosion resistant material (oxidation scale preventing material) mainly composed of cobalt is provided. Further, a bushing step portion 15 is formed at the upper end portion of the bushing 14 so that the inner peripheral surface 14a is recessed in the outer peripheral direction, and the inner side in the radial direction is recessed vertically downward when viewed from the upper surface 14b. The bushing step portion 15 has a vertical surface 15a facing the outer peripheral surface 12a of the valve stem 12, and a horizontal surface 15b extending substantially horizontally from the lower end of the vertical surface 15a of the bushing step portion 15 to the inside in the deformation direction and radially outward. The bushing 14 is formed in an annular shape over the entire inner circumference. In the present embodiment, as shown in FIG. 2, the distance L1 between the inner peripheral surface 14a of the bushing 14 and the outer peripheral surface 12a of the valve stem 12 (that is, the radial length of the gap 27) is from 0.1 mm to 1. The radial length L2 of the horizontal surface 15b of the bushing step portion 15 is set to 0.5 mm to 3.0 mm. Note that the wear / corrosion resistant material mainly composed of cobalt is, for example, Stellite (registered trademark).

  The valve body 9 and the bushing 14 are disposed so that the upper end of the valve body 9 and the lower end of the bushing 14 are in contact with each other when the valve body 9 is in a fully open state (a state in which the valve body 9 has moved most vertically upward). ing. That is, when the valve body 9 is in the closed state, the upper end of the valve body 9 and the lower end of the bushing 14 are separated from each other, but when the valve stem 12 moves vertically upward to open the valve body 9, The valve body 9 fixed to the valve rod 12 also moves upward, and the upper end of the valve body 9 and the lower end of the bushing 14 come into contact with each other. In this way, when the valve body 9 is fully closed and steam flows from the steam inlet pipe 6, sealing is performed so that steam does not leak from between the valve body 9 and the bushing 14.

  The connector 16 includes a connector upper part 17 (see FIG. 1) that is fixed to the valve stem 12 and a connector lower part 18 that is separated from the outer peripheral surface 12a of the valve stem 12. The connector lower portion 18 has a cylindrical shape extending vertically, and the valve rod 12 is inserted therein. The connector lower portion 18 includes an inner peripheral surface 18a that is spaced from and opposed to the outer peripheral surface 12a of the valve stem 12, and a lower surface 18b that extends substantially horizontally outward from the lower end of the inner peripheral surface 18a. That is, when the valve stem 12 moves in the vertical up / down direction, the connector 16 also moves in the vertical up / down direction, but there is a bushing between the inner peripheral surface 18a of the connector lower portion 18 and the outer peripheral surface 12a of the valve stem 12. As in FIG. 14, a gap 27 is formed. In this embodiment, the inner peripheral surface 18a and the lower surface 18b of the connector lower portion 18 are subjected to, for example, nitriding treatment. In addition, a connector step portion 19 is formed at the lower end portion of the connector lower portion 18 so that the inner peripheral surface 18a is recessed in the outer peripheral direction and the inner side in the radial direction is recessed vertically upward when viewed from the lower surface 18b. The connector step portion 19 has a vertical surface 19a facing the outer peripheral surface 12a of the valve stem 12, and a horizontal surface 19b extending substantially horizontally from the upper end of the vertical surface 19a toward the inside in the deformation direction and radially outward. 18 is formed in an annular shape over the entire inner circumference. In the present embodiment, the distance L1 between the inner peripheral surface 18a of the connector lower portion 18 and the outer peripheral surface 12a of the valve stem 12 (that is, the radial length of the gap 27) is set from 0.1 mm to 1.0 mm. The length L2 in the radial direction of the horizontal surface 19b of the stepped portion 19 is set to 0.5 mm to 3.0 mm.

  The bushing 14 and the connector 16 are arranged so that the upper surface 14b of the bushing 14 and the lower surface 18b of the connector lower portion 18 are in contact with each other when the valve element 9 moves vertically downward and is closed. That is, when the valve element 9 is in the open state, the upper surface 14b of the bushing 14 and the lower surface 18b of the connector lower part 18 are separated from each other, but the valve stem 12 moves vertically downward to close the valve element 9. Then, the connector 16 fixed to the valve stem 12 also moves vertically downward, and the upper surface 14b of the bushing 14 and the lower surface 18b of the connector lower portion 18 come into contact with each other. When the moving device 5 applies a further downward load while the upper surface 14b of the bushing 14 and the lower surface 18b of the connector lower portion 18 are in contact, the lower surface 18b of the connector lower portion 18 presses the upper surface 14b of the bushing 14. It becomes. In this way, when the valve body 9 is closed, sealing is performed so that steam does not leak from between the bushing 14 and the connector 16. When the bushing 14 and the connector 16 are in contact, the vertical surface 15a of the bushing step portion 15 and the vertical surface 19a of the connector step portion 19 are substantially continuous surfaces.

  In the present embodiment, as shown in FIG. 2, the bushing step portion 15 is provided so as to be cut out including a portion that is not the build-up portion 14c of the bushing 14, but the bushing step portion 15 is shown in FIG. Thus, you may provide so that the build-up part 14c may be notched. In the embodiment of FIG. 4, the radial length L3 of the build-up portion 14c having wear resistance and corrosion resistance is set to 3.0 mm or more, and the radial length L4 of the horizontal surface 15b of the bushing step portion 15 is set to 0. .5 mm to 3.0 mm.

  The stem leak pipe 21 includes a vertical pipe 21a extending in the vertical vertical direction and a horizontal pipe 21b extending in a horizontal outer diameter direction from a part of the outer peripheral surface of the vertical pipe 21a. The vertical pipe 21a accommodates the upper end portion of the bushing 14 and the connector 16 therein. The horizontal pipe 21b communicates with a condenser (not shown) provided outside the steam valve. The horizontal pipe 21b is provided with a thermometer (temperature measuring means) 23 for measuring the temperature inside the horizontal pipe 21b. The thermometer 23 is connected to a control device (not shown). When the temperature of the horizontal tube 21b exceeds a predetermined temperature, the control device notifies the operator or the monitor by notification means (not shown).

  The control device includes, for example, a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), and a computer-readable storage medium. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program as an example, and the CPU reads the program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized. The program is preinstalled in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Etc. may be applied. The computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

  As shown in FIG. 1, the moving device 5 includes a lever 24 connected to the upper end of the connecting rod 13, and a spring 25 connected to one end of the lever 24 and urged so as to press the valve rod 12 vertically downward. And an actuator 26 that is connected to the other end of the lever 24 and moves the valve rod 12 in the vertical vertical direction. The valve rod 12 is reciprocated in the vertical vertical direction by the moving device 5, and the seat portion 10 of the valve body 9 is brought into contact with and separated from the valve seat 22.

  Next, the flow of steam according to the present embodiment will be described with reference to FIGS. The steam sent from the boiler (not shown) flows into the valve chamber 3 through the steam inlet pipe 6 as indicated by an arrow A in FIG. The steam flowing into the valve chamber 3 is supplied from the steam outlet pipe 7 to the steam turbine as indicated by an arrow B when the valve body 9 is in the open state. As described above, when the valve body 9 is fully opened, the valve body 9 and the bushing 14 come into contact with the upper end of the valve body 9 and the lower end of the bushing 14, and steam leaks from between the valve body 9 and the bushing 14. Not to be sealed. On the other hand, when the valve body 9 is in a closed state, the steam that has flowed into the valve chamber 3 stays in the valve chamber 3 and stops part of the flow of the steam.

  While the valve body 9 is changed from the fully closed state to the fully open state, a part of the steam in the valve chamber 3 is, as indicated by the solid line arrow in FIG. In some cases, it flows into the gap 27 formed between the terminal 12a and the terminal 12a. As described above, when the valve element 9 is fully closed, the bushing 14 and the connector 16 are in contact with the upper surface 14b of the bushing 14 and the lower surface 18b of the connector lower portion 18, and steam is also generated between the bushing 14 and the connector 16. Sealed to prevent leakage. However, while the valve element 9 is in the fully closed state, the contact surface between the bushing 14 and the connector 16 is not in close contact, and the contact between the bushing 14 and the connector 16 is indicated by the broken line arrow in FIG. The steam may leak from the surface to the vertical pipe 21a, and the steam leaked to the vertical pipe 21a is supplied to the condenser through the horizontal pipe 21b.

According to this embodiment, there exist the following effects.
In the present embodiment, the distance L1 between the vertical surfaces 15a and 19a of the bushing step portion 15 and the connector step portion 19 and the outer peripheral surface 12a of the valve stem 12 is a portion where the bushing 14 and the connector 16 are in contact with each other. In addition, it is provided to be longer in the radial direction than portions other than the bushing step portion 15 and the connector step portion 19. Thereby, for example, even if the contact portion between the bushing 14 and the connector 16 is deformed by the pressing force from the moving device 5, the deformed portion is unlikely to contact the valve stem 12. Accordingly, the deformed portion of the bushing 14 or the connector 16 comes into contact with the outer peripheral surface 12a of the valve stem 12, and is caused by the damage to the outer peripheral surface 12a of the valve stem 12 and the deformation portion being fixed to the outer peripheral surface 12a of the valve stem 12. It is possible to prevent the moving operation failure and improve the reliability. Moreover, since the increase in the amount of steam leakage resulting from damage to the outer peripheral surface 12a of the valve stem 12 can be prevented, the performance degradation can be suppressed.

  Further, in the present embodiment, the portion of the bushing 14 that contacts the connector 16 is provided with a built-up portion 14c formed of a wear-resistant and corrosion-resistant material mainly composed of cobalt. A foreign matter such as oxide scale is generated at the contact portion, and it becomes difficult to adhere. Thereby, when the bushing 14 and the connector 16 contact, it can contact, without interposing a foreign material, and can make the bushing 14 and the connector 16 contact | adhere suitably. Therefore, it is possible to suppress the leakage of steam from the contacting portion.

  Further, in this embodiment, the inner peripheral surface 14a of the bushing 14 is provided with the built-up portion 14c formed of a wear-resistant and corrosion-resistant material mainly composed of cobalt. Foreign matter such as oxide scale is generated and hardly adhered. Accordingly, it is possible to prevent deterioration of the slidability of the outer peripheral surface 12a of the valve stem 12 and the inner peripheral surface 14a of the bushing 14 caused by the generation and adhesion of foreign matters such as oxide scales on the inner peripheral surface 14a of the bushing 14. It is possible to prevent an increase in steam leakage due to damage to or damage to the outer peripheral surface 12a of the valve stem 12.

  Further, in the present embodiment, as shown in FIG. 2, when the steam leaks from the portion where the bushing 14 and the connector 16 contact, the leaked steam flows through the vertical pipe 21a and the horizontal pipe 21b. When steam flows through the horizontal pipe 21b, the temperature inside the horizontal pipe 21b changes. Therefore, by measuring the temperature inside the horizontal tube 21b with the thermometer 23, when a steam leak starts from the portion where the bushing 14 and the connector 16 are in contact with each other, a temperature rise different from the conventional one occurs. It is possible to grasp the leakage.

  Specifically, as shown in FIG. 5, the measured temperature inside the horizontal tube 21b is compared with the accumulated temperature data in the normal time inside the horizontal tube 21b (data indicated by the solid line in FIG. 5). When the valve body 9 is in the closed state, the bushing 14 and the connector 16 are normally in close contact with each other, so that no steam flows in the stem leak pipe 21, as shown by the solid line in FIG. The temperature inside 21b does not rise. Therefore, when the temperature inside the horizontal pipe 21b when the valve body 9 is in the closed state is higher than the normal temperature as shown by the one-dot chain line in FIG. 5, it is determined that steam leakage has occurred. be able to.

  Note that the present invention is not limited to the invention according to each of the above embodiments, and can be appropriately modified without departing from the gist thereof. For example, in this embodiment, the surface forming the bushing step 15 and the connector step 19 is a vertical surface and a horizontal surface, but the surface forming the bushing step 15 and the connector step 19 may be a curved surface. It can be an inclined surface. In this embodiment, the stepped portion is formed on both the bushing 14 and the connector 16. However, the stepped portion may be provided on either the bushing 14 or the connector 16.

  In the present embodiment, the configuration in which the vertical surface 15a of the bushing step portion 15 and the vertical surface 19a of the connector step portion 19 are continuous surfaces when the bushing 14 and the connector 16 are in contact with each other has been described. The present invention is not limited to this. The vertical surface 15a of the bushing step 15 and the vertical surface 19a of the connector step 19 may be discontinuous with the bushing 14 and the connector 16 in contact with each other. Specifically, the vertical surface 15a of the bushing step portion 15 may be located on the radially outer side than the vertical surface 19a of the connector step portion 19, or may be located on the radially inner side. When the vertical surface 15a of the bushing step portion 15 is located radially inward of the vertical surface 19a of the connector step portion 19, steam flows from the vertically lower side to the upper side (see the solid line arrow in FIG. 2). On the other hand, the portion where the bushing 14 and the connector 16 are in contact with each other is hidden by the vertical surface 15a of the bushing step portion 15, so that the leakage of steam from the portion where the bushing 14 and the connector 16 are in contact is suitably suppressed. can do.

  In the present embodiment, the example in which the seal structure is applied to the portion where the bushing 14 and the connector 16 are in contact has been described. However, the seal structure may be applied to the portion where the valve body 9 and the connector 16 are in contact with each other. In the present embodiment, the steam flow rate adjusting valve has been described. However, the present invention can also be applied to other valve structures such as a steam cutoff valve.

  Moreover, although the valve mechanism 2 of the steam flow control valve 1 of this embodiment demonstrated the example provided with the moving apparatus 5 which reciprocates the valve rod 12 to a vertical up-down direction, application of the steam flow control valve 1 of this embodiment is applied. The embodiment is not limited to this. The seal structure of the present invention includes, for example, a steam flow rate adjusting valve in which the entire longitudinal direction of the steam flow rate adjusting valve is disposed in the horizontal direction and the valve rod 12 is reciprocated in the horizontal direction, and the overall longitudinal direction of the steam flow rate adjusting valve. Can be used in a steam flow rate adjustment valve that reciprocally moves the valve rod 12 in the inclined direction.

1 Steam flow control valve (steam valve)
2 Valve mechanism 3 Valve chamber 5 Moving device (moving means)
9 Valve body 10 Seating portion 12 Valve rod 12a Outer peripheral surface 14 Bushing 14a Inner peripheral surface 14b Upper surface 14c Overlaying portion (oxidation scale adhesion preventing material)
15 Bushing step portion 16 Connector 18 Connector lower portion 18a Inner peripheral surface 18b Lower surface 19 Connector step portion 21 Stem leak pipe (leak pipe)
22 Valve seat 23 Thermometer (Temperature measuring means)
30 Steam turbine system

Claims (6)

A valve body that contacts and separates from the valve seat;
A valve stem that connects one end to the valve body and extends in one direction;
A bushing that has a cylindrical shape and supports the valve rod disposed therein slidably in the one direction;
A connector having a cylindrical shape, one end portion of which is arranged to face one end portion of the bushing, and moves in the one direction together with the valve rod,
Moving means for moving the valve stem in the one direction,
When the valve body is in close contact with the valve seat, the moving means brings the one end of the connector into contact with the one end of the bushing,
The inner peripheral surface of each of the bushing and the connector is spaced apart from the outer peripheral surface of the valve stem,
The inner peripheral surface of at least one of the one end portion of the bushing and the one end portion of the connector is longer than the inner peripheral surface of the portion other than the one end portion with respect to the distance away from the outer peripheral surface of the valve rod. Steam valve becoming.   The steam valve according to claim 1, wherein an oxide scale adhesion preventing material is provided on an upper surface of the bushing.   The steam valve according to claim 1 or 2, wherein an oxide scale adhesion preventing material is provided on an inner peripheral surface of the bushing facing the valve rod. A leak pipe provided on the outer peripheral side of the one end of the bushing and the one end of the connector so as to surround the one end of the bushing and the one end of the connector;
Temperature measuring means provided in the leak pipe;
The steam valve according to claim 1, further comprising: The steam valve according to any one of claims 1 to 4,
A steam turbine from which steam is led from the steam valve;
Steam turbine system equipped with. A valve body that contacts and separates from the valve seat;
A valve stem that connects one end to the valve body and extends in one direction;
A bushing that has a cylindrical shape and supports the valve rod disposed therein slidably in the one direction;
A connector having a cylindrical shape, one end portion of which is arranged to face one end portion of the bushing, and moves in the one direction together with the valve rod,
Moving means for moving the valve stem in the one direction,
When the valve body is in close contact with the valve seat, the moving means brings the one end of the connector into contact with the one end of the bushing,
The inner peripheral surface of each of the bushing and the connector is spaced apart from the outer peripheral surface of the valve stem,
The inner peripheral surface of at least one of the one end portion of the bushing and the one end portion of the connector is longer than the inner peripheral surface of the portion other than the one end portion with respect to the distance away from the outer peripheral surface of the valve rod. A steam valve,
A step of bringing the one end of the bushing into contact with the one end of the connector at the time of contact between the valve body and the valve seat;
A method of operating a steam valve, comprising: a step of separating the one end portion of the bushing and the one end portion of the connector when the valve body and the valve seat are separated from each other.

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