JP6914657B2 - Steam valve, steam turbine system with steam valve and how to operate the steam valve - Google Patents

Description

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

The steam turbine is provided with a valve such as a steam flow rate adjusting valve that regulates the flow rate of steam flowing into the steam turbine and a steam shutoff valve that shuts off or permits the inflow of steam into the steam turbine. Since the steam to the steam turbine is hot and high pressure, such valves require reliability in the opening and closing operation, and steam from the valve does not reduce the flow rate of steam flowing into the steam turbine. A mechanism may be provided to prevent leakage to the outside. For example, Patent Document 1 is provided with such a mechanism.

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

Japanese Unexamined Patent Publication No. 2003-27904

However, in the configuration described in Patent Document 1, since the portion where the convex portions are in surface contact with each other is close to the stop valve side valve shaft located on the inner peripheral side, when the surface pressure increases more than expected, or When it deteriorates over time, there is a possibility that the part that comes into contact with the surface will be deformed. When the surface contact part is deformed, the deformed part 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 part sticks to the stop valve side valve shaft, and the deformed part becomes If caught, it could affect the smooth movement of the valve stem. In addition, damage to the surface of the valve shaft on the stop valve side may increase the amount of steam leaking to the outside, which may affect the deterioration of performance.

The present invention has been made in view of such circumstances, and prevents contact between the valve stem surface and the deformed portion even if the seal portion of the support member that slidably supports the valve stem is deformed. It is an object of the present invention to provide a steam valve, a steam turbine system equipped with a steam valve, and a method of operating the steam valve.
Further provided are a steam valve 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, a steam turbine system provided with the steam valve, and a method for operating the steam valve. The purpose is.

In order to solve the above problems, the steam valve of the present invention, the steam turbine system provided with the steam valve, and the operation method of the steam valve employ the following means.
The steam valve according to one aspect of the present invention has a tubular shape and is arranged inside with a valve body that is in contact with and detached from the valve seat, and a valve rod that has one end connected to the valve body and extends in one direction. A bushing that slidably supports the valve stem in one direction, and a connector that has a tubular shape and has one end facing the one end of the bushing and moves in one direction together with the valve stem. The moving means includes a moving means for moving the valve stem in the one direction, and the moving means attaches 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 arranged so as to be separated from the outer peripheral surface of the valve stem, and at least one of the one end of the bushing and the one end of the connector. The distance between the inner peripheral surface of the valve rod and the outer peripheral surface of the valve stem is longer than that of the inner peripheral surface of the portion other than the one end portion.

By moving the connector that moves with the valve stem by the moving means and bringing it into contact with the connector, steam leaks from between the bushing and the connector. If the pressing force continues to act from the moving means at the time of contact between the bushing and the connector, the load continues to act on the portion where the bushing and the connector come into contact with each other. At this time, due to the load, 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 side of the valve stem. Even in such a case, in the above configuration, the inner peripheral surface of at least one of one end of the bushing and one end of the connector is separated from the outer peripheral surface of the valve stem by a distance from the inner peripheral surface of the other portion. Because it is also long, it is difficult to contact the valve stem even if a deformed part occurs. 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 occurs when the bushing or the deformed portion of the connector comes into contact with the outer peripheral surface of the valve stem. In addition, it is possible to prevent an increase in the amount of steam leakage due to damage to the outer peripheral surface of the valve stem.

Further, 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 at the portion in contact with the bushing connector, the oxide scale is easily generated and hardly adhered to the portion in contact with the bushing connector. As a result, when the bushing and the connector come into contact with each other, they can be brought into contact with each other without any foreign matter intervening, and the bushing and the connector can be suitably brought into close contact with each other. Therefore, it is possible to suppress the leakage of steam from the contacting portion.

Further, in the steam valve according to one aspect of the present invention, an oxide scale adhesion preventing material may be provided on the inner peripheral surface of the bushing facing the valve stem.

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 easily generated and adhered to the inner peripheral surface of the bushing. Therefore, it is possible to prevent deterioration of the slidability of the valve stem to the moving operation and damage to the outer peripheral surface of the valve stem, which are caused by the adhesion of the oxide scale to the inner peripheral surface of the bushing.

Further, the steam valve according to one aspect of the present invention is provided on the outer peripheral side of the one end portion of the bushing and the one end portion of the connector so as to surround the one end portion of the bushing and the one end portion of the connector. A leak pipe and a temperature measuring means provided on the leak pipe may be provided.

In the above configuration, when steam leaks from the portion where the bushing and the connector come into contact with each other, the leaked steam circulates in 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 contacting portion.

Further, the steam turbine system according to one aspect of the present invention includes a steam valve as described above and a steam turbine in which steam is guided from the steam valve.

Further, the operation method of the steam valve according to one aspect of the present invention has a tubular shape, a valve body that is in contact with and detached from the valve seat, a valve rod that has one end connected to the valve body and extends in one direction. , A bushing that slidably supports the valve rod arranged inside in the one direction, and a tubular shape, one end of which is arranged to face one end of the bushing, and the one direction together with the valve rod. The moving means includes a connector for moving the valve rod in one direction and a moving means for moving the valve stem in one direction. The inner peripheral surfaces of the bushing and the connector are arranged apart from the outer peripheral surface of the valve stem so as to be in contact with the one end portion of the bushing, and the one end portion of the bushing and the one end portion of the connector. The inner peripheral surface of at least one of the above is a steam valve whose distance from the outer peripheral surface of the valve stem is longer than the inner peripheral surface of a portion other than the one end portion, and the valve body and the said valve body. The step of bringing the one end of the bushing into contact with the one end of the connector at the time of contact with the valve seat, and the step of bringing the valve body and the valve seat apart, the one end of the bushing and the connector. It has a step of separating it from one end.

According to the present invention, even if the seal portion of the support member that slidably supports the valve stem is deformed, it is possible to prevent the deformed portion from coming into contact with the outer peripheral surface of the valve stem. Further, it is possible to prevent the amount of steam leakage from increasing due to the contact between the deformed portion and the outer peripheral surface of the valve stem.

It is a vertical sectional view which shows the steam valve which concerns on embodiment of this invention. It is a vertical cross-sectional view which shows the main part of the steam valve of FIG. It is a schematic perspective view which shows the bushing and the valve stem of the steam valve of FIG. It is a schematic vertical sectional view which shows the modification of the main part of the steam valve of FIG. It is a graph which shows the time-dependent change state of the temperature measurement value of a stem leak tube.

Hereinafter, an embodiment of a steam valve, a steam turbine system including a steam valve, and an operation method of the steam valve according to the present invention will be described with reference to FIGS. 1 to 5.
As shown in FIG. 1, the steam flow rate adjusting valve (steam valve) 1 according to the present embodiment is provided in the steam turbine system 30 and has a valve mechanism 2 for adjusting the flow rate of steam flowing into the steam turbine (not shown). A casing 4 that accommodates the lower portion of the valve mechanism 2 to form a valve chamber 3 and a moving device (moving means) 5 that reciprocates the valve mechanism 2 in the vertical and vertical directions are provided. The casing 4 includes a casing main body 4a and a lid 8 that is fastened and fixed to the casing main body 4a with bolts 20. Further, the casing main body 4a forms a steam inlet pipe 6 for flowing steam 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 extending vertically in the vertical direction to fix the valve body 9 at the lower end portion, a connecting rod 13 extending vertically in the vertical direction to connect the valve rod 12 and the moving device 5, and a lid body 8. A bushing 14 that is fixed to and slidably supports the valve rod 12 in the vertical vertical direction, a connector 16 that is located above the bushing 14 and moves in the vertical vertical direction together with the valve rod 12, and a tubular that extends in the vertical vertical direction. The member is provided with a stem leak pipe (leak pipe) 21 provided so as to surround the upper end portion of the bushing 14 and the connector 16 on the upper end portion of the bushing 14 and the outer peripheral side of the connector 16.

The valve body 9 includes a seating portion 10 that comes into contact with and separates from the valve seat 22, and a fixing portion 11 that is fixed to the valve stem 12 above the seating portion 10. The valve body 9 moves vertically and vertically by the driving force of the moving device 5, and the seating portion 10 comes into contact with the valve seat 22 located below the valve body 9 to cut off the supply of steam to the steam turbine. A state (hereinafter, a state in which the seating portion 10 and the valve seat 22 are in contact with each other to cut off the supply of steam to the steam turbine is referred to as a "closed state"), and the seating portion is moved vertically upward from the closed state. A state in which steam can be supplied to the steam turbine by separating the 10 and the valve seat 22 (hereinafter, a state in which the seating portion 10 and the valve seat 22 are separated from each other and steam can be supplied to the steam turbine. It is called "open state"). In the open state, steam flows in from the steam inlet pipe 6 in the A direction and outflows 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 rod 12 moves vertically in the vertical direction by a driving force from the moving device 5 (see FIG. 1) to bring the valve body 9 into a closed state or an open state.

As shown in FIGS. 2 and 3, the bushing 14 has a cylindrical shape extending vertically, and a valve rod 12 is inserted therein. The bushing 14 includes an inner peripheral surface 14a that is separated from and opposed to the outer peripheral surface 12a of the valve rod 12, and an upper surface 14b that extends substantially horizontally outward in the radial direction 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 rod 12 so that the valve rod 12 can move vertically and vertically. It is preferable that the inner peripheral surface 14a and the upper surface 14b of the bushing 14 are provided with wear-resistant and corrosion-resistant materials in order to prevent the generation and adhesion of foreign substances such as oxide scales. In the present embodiment, for example, a build-up portion 14c formed by spraying a wear- and corrosion-resistant material (oxidation scale preventive material) containing cobalt as a main component 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 in the vertical downward direction 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 rod 12 and a horizontal plane 15b extending substantially horizontally from the lower end of the vertical surface 15a of the bushing step portion 15 inward in the deformation direction toward the outside in the radial direction. However, it is formed in an annular shape over the entire inner circumference of the bushing 14. In the present embodiment, as shown in FIG. 2, the separation distance L1 (that is, the radial length of the gap 27) between the inner peripheral surface 14a of the bushing 14 and the outer peripheral surface 12a of the valve stem 12 is set from 0.1 mm to 1. It is set to 0 mm, and the radial length L2 of the horizontal plane 15b of the bushing step portion 15 is set to 0.5 mm to 3.0 mm. The wear- and corrosion-resistant material containing cobalt as a main component is, for example, Stellite (registered trademark).

The valve body 9 and the bushing 14 are arranged so that the upper end of the valve body 9 and the lower end of the bushing 14 come into contact with each other when the valve body 9 is in the fully open state (the state in which the valve body 9 moves 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 rod 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 in from the steam inlet pipe 6, the valve body 9 and the bushing 14 are sealed so that the steam does not leak.

The connector 16 includes a connector upper portion 17 (see FIG. 1) fixed to the valve rod 12, and a connector lower portion 18 separated from the outer peripheral surface 12a of the valve rod 12. The lower portion 18 of the connector has a cylindrical shape extending vertically, and a valve rod 12 is inserted therein. The connector lower portion 18 includes an inner peripheral surface 18a that is separated from and faces the outer peripheral surface 12a of the valve rod 12, and a lower surface 18b that extends substantially horizontally outward in the radial direction from the lower end of the inner peripheral surface 18a. That is, when the valve stem 12 moves in the vertical vertical direction, the connector 16 also moves in the vertical vertical direction, but a bushing is provided between the inner peripheral surface 18a of the connector lower portion 18 and the outer peripheral surface 12a of the valve stem 12. A gap 27 is formed in the same manner as in 14. In the present embodiment, the inner peripheral surface 18a and the lower surface 18b of the lower portion 18 of the connector are subjected to, for example, nitriding treatment. Further, at the lower end portion of the lower portion 18 of the connector, a connector step portion 19 is formed in which the inner peripheral surface 18a is recessed in the outer peripheral direction and the inner side in the radial direction is recessed in the vertically upward direction 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 plane 19b extending substantially horizontally from the upper end of the vertical surface 19a inward in the deformation direction to the outside in the radial direction. It is formed in an annular shape over the entire inner circumference of 18. In the present embodiment, the separation distance L1 (that is, the radial length of the gap 27) between the inner peripheral surface 18a of the connector lower portion 18 and the outer peripheral surface 12a of the valve rod 12 is set from 0.1 mm to 1.0 mm, and the connector is connected. The length L2 of the horizontal plane 19b of the step portion 19 in the radial direction 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 lower portion 18 of the connector come into contact with each other when the valve body 9 moves vertically downward and is in the closed state. That is, when the valve body 9 is in the open state, the upper surface 14b of the bushing 14 and the lower surface 18b of the connector lower portion 18 are separated from each other, but the valve rod 12 moves vertically downward in order to close the valve body 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 further applies a 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 with each other, 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, the bushing 14 and the connector 16 are sealed so that steam does not leak. Further, when the bushing 14 and the connector 16 are in contact with each other, 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 include a portion of the bushing 14 that is not the built-up portion 14c, but the bushing step portion 15 is shown in FIG. As described above, the overlay portion 14c may be provided so as to be cut out. In the embodiment of FIG. 4, the radial length L3 of the overlay portion 14c having wear resistance and corrosion resistance is set to 3.0 mm or more, and the radial length L4 of the horizontal plane 15b of the bushing step portion 15 is set to 0. It is set to 5.5 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 the horizontal outer diameter direction from a part of the outer peripheral surface of the vertical pipe 21a. The vertical pipe 21a houses the upper end portion of the bushing 14 and the connector 16 inside. 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 pipe 21b exceeds a predetermined temperature, the control device notifies the operator or the observer by a notification means (not shown).

The control device is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. Then, as an example, a series of processes for realizing various functions are stored in a storage medium or the like in the form of a program, and the CPU reads this program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized. The program is installed in a ROM or other storage medium in advance, is provided in a state of being stored in a computer-readable storage medium, or is distributed via a wired or wireless communication means. Etc. may be applied. Computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, semiconductor memories, and 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 urging the valve rod 12 to press vertically downward. , It is provided with an actuator 26 which is connected to the other end of the lever 24 and moves the valve stem 12 in the vertical vertical direction. The valve rod 12 is reciprocated vertically and vertically by the moving device 5, and the seating portion 10 of the valve body 9 is brought into contact with and separated from the valve seat 22.

Next, the steam flow of this embodiment will be described with reference to FIGS. 1 and 2. The steam sent from the boiler (not shown) flows into the valve chamber 3 through the steam inlet pipe 6 as shown by the arrow A in FIG. When the valve body 9 is in the open state, the steam flowing into the valve chamber 3 is supplied to the steam turbine from the steam outlet pipe 7 as shown by the arrow B. As described above, when the valve body 9 and the bushing 14 are in the fully open state, the upper end of the valve body 9 and the lower end of the bushing 14 come into contact with each other, and steam leaks from between the valve body 9 and the bushing 14. It is sealed so as not to. On the other hand, when the valve body 9 is in the closed state, the steam flowing into the valve chamber 3 stays in the valve chamber 3, and the steam flow is partially stopped.

While the valve body 9 changes from the fully closed state to the fully open state, a part of the steam in the valve chamber 3 is shown by the solid line arrow in FIG. 2, the inner peripheral surface 14a of the bushing 14 and the outer peripheral surface of the valve rod 12. It may flow into the gap 27 formed between the 12a and the 12a. As described above, when the valve body 9 is fully closed, the bushing 14 and the connector 16 come into contact with the upper surface 14b of the bushing 14 and the lower surface 18b of the connector lower portion 18, and steam also flows from between the bushing 14 and the connector 16. It is sealed to prevent leakage. However, while the valve body 9 is in the fully closed state, the contact surfaces between the bushing 14 and the connector 16 are not in close contact with each other, and as shown by the broken arrow in FIG. 2, the bushing 14 and the connector 16 are in contact with each other. Steam may leak from the surface to the vertical pipe 21a, and the steam leaking to the vertical pipe 21a is supplied to the condenser through the horizontal pipe 21b.

According to this embodiment, the following effects are exhibited.
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, which are the portions where the bushing 14 and the connector 16 come into contact with each other, and the outer peripheral surface 12a of the valve rod 12 is set. , It is provided so as to be longer in the radial direction than the portions other than the bushing step portion 15 and the connector step portion 19. As a result, 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 come into contact with the valve stem 12. Therefore, due to damage to the outer peripheral surface 12a of the valve stem 12 and sticking of the deformed portion to the outer peripheral surface 12a of the valve rod 12, which occurs when 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. It is possible to prevent movement malfunction and improve reliability. Further, since it is possible to prevent an increase in the amount of steam leakage due to damage to the outer peripheral surface 12a of the valve stem 12, it is possible to suppress a deterioration in performance.

Further, in the present embodiment, the portion of the bushing 14 that comes into contact with the connector 16 is provided with a built-up portion 14c formed of a wear- and corrosion-resistant material containing cobalt as a main component, so that the bushing 14 has a connector 16 and a built-up portion 14c. Foreign matter such as oxide scale is generated on the contacted portion, which makes it difficult for foreign matter to adhere. As a result, when the bushing 14 and the connector 16 come into contact with each other, they can be brought into contact with each other without any foreign matter intervening, and the bushing 14 and the connector 16 can be suitably brought into close contact with each other. Therefore, it is possible to suppress the leakage of steam from the contacting portion.

Further, in the present embodiment, the inner peripheral surface 14a of the bushing 14 is provided with a built-up portion 14c formed of a wear-resistant and corrosion-resistant material containing cobalt as a main component, so that the inner peripheral surface 14a of the bushing 14 is provided. Foreign matter such as oxide scale is generated and difficult to adhere. Therefore, it is possible to prevent the slidability of the outer peripheral surface 12a of the valve stem 12 and the inner peripheral surface 14a of the bushing 14 from being deteriorated, which is caused by the generation and adhesion of foreign matter such as an oxide scale to the inner peripheral surface 14a of the bushing 14. This makes it possible to prevent an increase in steam leakage due to damage or scratches on the outer peripheral surface 12a of the valve stem 12.

Further, in the present embodiment, as shown in FIG. 2, when steam leaks from the portion where the bushing 14 and the connector 16 come into contact with each other, the leaked steam circulates in 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 pipe 21b with the thermometer 23, when steam leakage starts from the portion where the bushing 14 and the connector 16 come into contact, a temperature rise different from the conventional one occurs at an early stage. You can grasp the leak.

Specifically, as shown in FIG. 5, the measured temperature inside the horizontal tube 21b is compared with the accumulated normal temperature data inside the horizontal tube 21b (data shown 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 steam does not flow into the stem leak pipe 21 and the horizontal pipe is 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 closed is higher than the normal temperature as shown by the alternate long and short dash line in FIG. 5, it is determined that steam leakage has occurred. be able to.

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 the present embodiment, the surfaces forming the bushing step portion 15 and the connector step portion 19 are vertical surfaces and horizontal surfaces, but the surfaces forming the bushing step portion 15 and the connector step portion 19 may be curved surfaces. It may be an inclined surface. Further, in the present embodiment, the step portion is formed on both the bushing 14 and the connector 16, but the step portion may be provided on either the bushing 14 or the connector 16.

Further, in the present embodiment, when the bushing 14 and the connector 16 are in contact with each other, the vertical surface 15a of the bushing step portion 15 and the vertical surface 19a of the connector step portion 19 have been described as having continuous surfaces. The present invention is not limited to this. The vertical surface 15a of the bushing step portion 15 and the vertical surface 19a of the connector step portion 19 may be discontinuous surfaces in a state where the bushing 14 and the connector 16 are in contact with each other. Specifically, the vertical surface 15a of the bushing step portion 15 may be located radially outside the vertical surface 19a of the connector step portion 19, or may be located inside in the radial direction. When the vertical surface 15a of the bushing step 15 is located radially inside the vertical surface 19a of the connector step 19, steam flowing from the vertically lower side to the upper side (see the solid line arrow in FIG. 2). On the other hand, since the portion where the bushing 14 and the connector 16 are in contact is hidden behind the vertical surface 15a of the bushing step portion 15, the leakage of steam from the portion where the bushing 14 and the connector 16 are in contact is suitably suppressed. can do.

Further, 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 with each other has been described, but the seal structure may be applied to the portion where the valve body 9 and the connector 16 are in contact with each other. Further, in the present embodiment, the steam flow rate adjusting valve has been described, but the present invention can also be applied to other valve structures such as a steam shutoff valve.

Further, although the valve mechanism 2 of the steam flow rate adjusting valve 1 of the present embodiment includes a moving device 5 for reciprocating the valve rod 12 in the vertical vertical direction, the application of the steam flow rate adjusting valve 1 of the present embodiment has been described. The aspect is not limited to this. The seal structure of the present invention is, for example, a steam flow rate adjusting valve in which the entire longitudinal direction of the steam flow rate adjusting valve is arranged horizontally to reciprocate the valve rod 12 in the horizontal direction, or the entire longitudinal direction of the steam flow rate adjusting valve. Can also be used for a steam flow rate adjusting valve that reciprocates the valve rod 12 in the inclined direction by arranging the valve rod 12 inclining from the vertical direction.

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

Claims (6)

The valve body that comes in and out of the valve seat,
A valve rod that connects one end to the valve body and extends in one direction,
A bushing that has a tubular shape and slidably supports the valve stem arranged inside in the one direction.
A connector that has a tubular shape, one end of which is arranged to face one end of the bushing, and moves in one direction together with the valve stem.
A moving means for moving the valve stem in the one direction is provided.
The moving means brings the one end of the connector into contact with 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 arranged apart from the outer peripheral surface of the valve stem.
The inner peripheral surface of at least one of the one end of the bushing and the one end of the connector is longer than the inner peripheral surface of the portion other than the one end in a distance away from the outer peripheral surface of the valve stem. Steam valve. The steam valve according to claim 1, wherein an oxide scale adhesion preventive material is provided on the upper surface of the bushing. The steam valve according to claim 1 or 2, wherein an oxide scale adhesion preventing material is provided on the inner peripheral surface of the bushing facing the valve stem. 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.
The temperature measuring means provided in the leak pipe and
The steam valve according to any one of claims 1 to 3. The steam valve according to any one of claims 1 to 4,
A steam turbine in which steam is guided from the steam valve and
Steam turbine system with. The valve body that comes in and out of the valve seat,
A valve rod that connects one end to the valve body and extends in one direction,
A bushing that has a tubular shape and slidably supports the valve stem arranged inside in the one direction.
A connector that has a tubular shape, one end of which is arranged to face one end of the bushing, and moves in one direction together with the valve stem.
A moving means for moving the valve stem in the one direction is provided.
The moving means brings the one end of the connector into contact with 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 arranged apart from the outer peripheral surface of the valve stem.
The inner peripheral surface of at least one of the one end of the bushing and the one end of the connector is longer than the inner peripheral surface of the portion other than the one end in a distance away from the outer peripheral surface of the valve stem. It is a steam valve that has become
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 for 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.

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