JP6462335B2 - Valve casing, valve provided with the same, turbine device provided with the valve, and method for preventing atmospheric gas from entering into the valve casing - Google Patents

Description

  The present invention relates to a valve casing in a steam valve or the like of a steam turbine provided in a floating production storage and loading facility (FPSO), a valve provided with the valve, a turbine device including the valve, and a method for preventing atmospheric gas from entering the valve casing. It is about.

  As disclosed in Patent Document 1, in a steam valve such as a main steam stop valve and a steam control valve installed at a main steam inlet of a steam turbine, high-temperature and high-pressure main steam is supplied from a valve shaft holding portion of a valve casing. In order to prevent leakage to the outside, the guide bush (valve shaft holding part) has a labyrinth structure, and the labyrinth structure is configured in two stages, and a leak-off chamber is provided between them to provide a first-stage labyrinth structure. It is known that the leaked steam that has passed is sent from the leak-off chamber to the leaked steam outlet.

JP 2011-122503 A

  Steam valves used in steam turbines installed on decks such as floating production, storage and offloading (abbreviated as FPSO), which produce and store natural gas offshore, In addition to preventing the main steam from leaking, it is necessary to prevent the inflammable gas contained in the air around the steam turbine from entering the valve shaft holder.

In particular, a negative pressure region may be formed in the leak-off chamber or the leak steam outlet in order to guide main steam leaked from the steam valve to the condenser. When a negative pressure region is formed in the leak-off chamber and leakage steam outlet, there is a possibility that combustible gas contained in the air around the steam valve from being sucked to the valve shaft holder.

  Moreover, not only the combustible gas contained in the air but also the active gas (oxygen or the like) contained in the air enters the valve shaft holding portion, the valve shaft holding portion and the valve shaft are oxidized, and the steam valve There is a risk of sticking. Particularly on FPSO, since the steam turbine is required to operate continuously for a long time (for example, several years), it is necessary to prevent the steam valve from sticking.

  The present invention has been made in view of such circumstances, and a valve casing capable of preventing a combustible gas or an active gas contained in the atmosphere around the valve from entering the valve shaft holding portion, It is an object of the present invention to provide a valve equipped with a valve, a turbine device equipped with a valve, and a method for preventing atmospheric gas from entering a valve casing.

  In order to solve the above problems, the present invention employs the following means.

That is, the valve casing according to the first aspect of the present invention includes at least a valve shaft of a working fluid flow path through which a working fluid flows and a flow rate control member that controls the flow rate of the working fluid inside the working fluid flow path. And a valve shaft holding portion having one end connected to the working fluid flow path, wherein the valve shaft holding portion supplies an inert gas to the shaft hole of the valve shaft. The valve shaft holding portion is provided with a leak fluid recovery passage that guides leaked fluid leaking from the inside of the working fluid flow channel to the leak fluid recovery portion using a pressure difference with the working fluid flow channel. The inert gas supply unit is connected to the atmosphere side of the leak fluid recovery passage, and a part of the inert gas is transferred from the other end side of the valve shaft holding unit to the outside of the valve shaft holding unit. It is characterized by letting it flow out .

  According to this valve casing, the inert gas is supplied from the inert gas supply unit to the shaft hole of the valve shaft holding unit, and this inert gas flows out from the gap between the shaft hole and the valve shaft. . For this reason, gas such as air around the valve cannot enter the valve shaft holding portion from the shaft hole. Therefore, for example, even if combustible gas is contained in the atmosphere around the valve, the combustible gas is not sucked into the valve. Moreover, it is possible to prevent sticking due to the active gas (oxygen or the like) contained in the air entering the valve shaft holder and oxidizing the valve shaft holder and the valve shaft.

Further , the inert gas supplied from the inert gas supply unit to the shaft hole of the valve shaft holding unit easily flows into the valve shaft holding unit due to a pressure difference from the leak fluid recovery unit. Therefore, it is possible to reliably supply the inert gas to the inside of the valve shaft holding portion and prevent outside air from entering the inside of the valve.

  In the valve casing having the above-described configuration, it is preferable that the inert gas is supplied at a pressure higher than atmospheric pressure, and a gas flow confirmation unit for confirming the flow of the inert gas is provided.

  Thereby, the flow of the inert gas supplied to the valve shaft holding portion can be confirmed, and the supply of the inert gas is prevented from stagnation and the outside air is prevented from entering the valve shaft holding portion. be able to.

  In the valve casing configured as described above, the inert gas is preferably nitrogen gas. By using nitrogen gas as the inert gas, the inert gas can be procured at a low cost.

  In the valve casing configured as described above, the inert gas supply unit is connected to an air component separator that separates nitrogen gas from the air, and the nitrogen gas separated by the air component separator is used as the inert gas. You may make it use.

  In this way, nitrogen gas is separated from the air by an air component separator, and by using this nitrogen gas as an inert gas, pure nitrogen gas is purchased and transported to the valve installation site or replenished. In addition, nitrogen gas can be separated from on-site air and used as an inert gas, and the procurement of the inert gas is easy and inexpensive.

  A valve according to a second aspect of the present invention includes the valve casing according to any one of the above aspects. Thereby, the combustible gas and active gas contained in the air around the steam can be prevented from entering the valve shaft holder.

A turbine apparatus according to a third aspect of the present invention includes the valve according to the above aspect.
In this turbine apparatus, since the inert gas is supplied from the inert gas supply unit to the shaft hole of the valve shaft holding unit of the valve, air such as air around the valve and flammable gas is discharged from the shaft hole to the valve shaft. It becomes impossible to enter the inside of the holding part. Therefore, for example, even if combustible gas is contained in the atmosphere around the valve, the combustible gas is not sucked into the valve.
Further, since active gas (oxygen or the like) contained in the air does not enter the valve shaft holding portion, it is possible to prevent sticking due to oxidation of the valve shaft holding portion and the valve shaft, thereby improving the safety and reliability of the turbine device. be able to.

An atmosphere gas intrusion prevention method for a valve casing according to a fourth aspect of the present invention includes a working fluid flow path through which a working fluid flows, and a flow rate control member that controls a flow rate of the working fluid inside the working fluid flow path. An atmosphere gas intrusion prevention method for a valve casing, comprising at least a valve shaft and a valve shaft holding portion having one end connected to the working fluid flow path, wherein the valve shaft in the valve shaft holding portion An inert gas is supplied to the shaft hole, and the leaked fluid leaked from the inside of the working fluid channel is supplied to the valve shaft holding unit to the leaked fluid recovery unit using a pressure difference with the working fluid channel. A leak fluid recovery passage is provided, the inert gas is supplied to a position on the atmosphere side of the leak fluid recovery passage, and a part of the inert gas is supplied to the valve shaft from the other end side of the valve shaft holding portion. It is caused to flow out to the outside of the holding portion And wherein the door.

  According to this method for preventing atmospheric gas from entering the valve casing, the inert gas is supplied to the shaft hole of the valve shaft holder, so that gas such as air around the valve and flammable gas is not allowed to flow inside the valve shaft holder. It becomes impossible to enter. Moreover, it is possible to prevent sticking due to the active gas (oxygen or the like) contained in the air entering the valve shaft holder and oxidizing the valve shaft holder and the valve shaft.

  As a result, the inert gas supplied from the inert gas supply unit to the shaft hole of the valve shaft holding unit can easily flow into the valve shaft holding unit due to a pressure difference from the leak fluid recovery unit. Therefore, it is possible to reliably supply the inert gas to the inside of the valve shaft holding portion and prevent outside air from entering the inside of the valve.

  As described above, according to the valve casing according to the present invention, the valve provided with the valve, the turbine device provided with the valve, and the atmospheric gas intrusion prevention method for the valve casing, the combustible gas contained in the atmosphere around the valve, It is possible to prevent the active gas from entering the valve shaft holding portion.

It is a longitudinal section showing the main steam stop valve concerning a 1st embodiment of the present invention. It is a figure which expands the II section of FIG. 1 and shows 1st Embodiment of this invention. It is a longitudinal cross-sectional view of the steam control valve which shows 2nd Embodiment of this invention.

  Below, the valve casing which concerns on embodiment of this invention, the valve provided with this, and the atmospheric gas penetration | invasion prevention method of a valve casing are demonstrated, referring drawings.

[First Embodiment]
FIG. 1 is a longitudinal sectional view showing an example of a main steam stop valve (valve) according to the first embodiment of the present invention.
The main steam stop valve 1 is connected to a main steam inlet 2 of a steam turbine (turbine device) (not shown), and includes a valve casing 5 including a casing body 3 and a casing lid 4. Inside the valve casing 5, a steam inlet passage 6 (working fluid passage) and a steam outlet passage 7 (working fluid passage) are formed horizontally and in steps, and the ends of these steam passages 6, 7 are formed. A valve seat 8 (flow rate control member) is formed in a portion where the portions overlap each other. The piston-like valve body 9 (flow rate control member) that opens and closes the valve seat 8 is inside the valve body sliding cylinder 10 formed in the casing lid 4 so as to be orthogonal to the passage direction of the steam passages 6 and 7. The valve seat 8 is opened and closed by sliding up and down.

  The valve casing 5 is provided with a valve shaft holding portion 12 on the opposite side (lower side) of the valve seat 8 across the steam outlet passage 7. The valve shaft holding portion 12 has a valve shaft 13 (flow rate control member). Is slidably held in the axial direction. One end (upper end) of the valve shaft 13 is connected to the valve body 9, an intermediate portion penetrates the valve shaft holding portion 12, and the other end (lower end) is cupped to an actuator 14 installed outside the valve casing 5. It is connected via a ring 15. When the actuator 14 is actuated, the valve shaft 13 slides in the axial direction to move the valve body 9 to open and close the valve seat 8 (the valve body 9 is closed in FIG. 1). As indicated by an arrow ST, main steam (working fluid) supplied to the steam turbine flows from the steam inlet passage 6 through the valve seat 8 to the steam outlet passage 7, and when the valve body 9 closes the valve seat 8, the main steam is supplied. Steam flow stops. The pressure of the main steam ST is higher than the atmospheric pressure (0 barg), and is about 5 barg for the low level and about 60 barg for the high level.

  The valve shaft holding portion 12 is provided with a bearing-shaped upper guide bush 18 and a lower guide bush 19 that support the valve shaft 13, and a shaft hole 20 formed in the upper and lower guide bushes 18, 19. The valve shaft 13 is slidably inserted. A labyrinth structure is provided between the shaft hole 20 and the valve shaft 13 so that main steam leakage is minimized. However, since the leak cannot be completely prevented, the valve shaft holding portion 12 is provided with a leak fluid recovery passage.

  As the leakage fluid recovery passage, a seal steam receiver passage 21 and a ground steam condenser return passage 22 communicate with the valve shaft holder 12. In these passages 21 and 22, a part of the main steam in the steam outlet passage 7 passes between the valve shaft 13 and the upper and lower guide bushes 18 and 19 (shaft hole 20) to the atmosphere side (external). The leaked steam (LS: leaked fluid) that is about to leak into the tank is guided to a predetermined place by utilizing the pressure difference with the steam outlet passage 7 to prevent the leaked steam from leaking to the atmosphere side. is there.

  Each of the upper guide bush 18 and the lower guide bush 19 is provided with leak-off chambers 18a and 19a in the middle thereof. One end of the seal steam receiver passage 21 is connected to the leak-off chamber 18a, and the other end is connected to the seal steam receiver 24 (leak fluid recovery unit). The pressure of the seal steam receiver passage 21 is set to about 0.1 barg, for example.

  On the other hand, the ground steam condenser return passage 22 is provided on the atmosphere side (outside) of the seal steam receiver passage 21, and one end of the valve shaft 13 is between the upper guide bush 18 and the lower guide bush 19. The other end is connected to the ground steam condenser 25 (leak fluid recovery part). For example, a negative pressure of about −0.02 barg is applied to the ground steam condenser return passage 22.

  As shown by arrows LS in FIG. 1 and FIG. 2, leaked steam (flowing from the steam outlet passage 7 to the leak-off chamber 18 a through the valve shaft 13 and the upper guide bush 18 (shaft hole 20)). The leakage fluid) is guided to the seal steam receiver passage 21 and the ground steam condenser return passage 22 from the pressure difference, and flows to the seal steam receiver 24 or the ground steam condenser 25. As a result, the leaked steam is prevented from leaking from the valve shaft holding portion 12 to the atmosphere side.

  Further, when steam does not leak from the steam outlet passage 7, the seal steam tends to flow out from the seal steam receiver passage 21 to the atmosphere side by the pressure of about 0.1 barg set in the seal steam receiver passage 21. However, since this seal steam flows into the ground steam condenser return passage 22 having a negative pressure and flows into the ground steam condenser 25, it does not leak to the atmosphere side.

  Furthermore, as shown in FIG. 2 in an enlarged manner, the valve shaft holding portion 12 is connected to the atmosphere side (lower side) with respect to the ground steam condenser return passage 22 which is a leak fluid recovery passage, An inert gas supply passage 28 is provided. One end of the inert gas supply passage 28 communicates with, for example, the leak-off chamber 19 a of the lower guide bush 19, and the other end is connected to the air supply pump 30. In addition, an air component separator 29 and a gas flow confirmation unit 31 are connected to an intermediate portion of the inert gas supply passage 28. An inert gas supply unit 32 includes an inert gas supply passage 28, an air component separator 29, an air supply pump 30, and a gas flow confirmation unit 31. The inert gas supply unit 32 supplies an inert gas to the shaft hole 20 of the valve shaft holding unit 12 and fills the shaft hole 20 with the inert gas.

  In the inert gas supply unit 32, an inexpensive nitrogen gas is preferable as a gas used as the inert gas. However, the inert gas is not necessarily limited to the nitrogen gas, and other types of inert gas such as argon gas may be used. Is also possible.

  The nitrogen gas is supplied at a pressure higher than atmospheric pressure (for example, about 0.1 barg), and the circulation of the nitrogen gas can be confirmed by the gas circulation confirmation unit 31. The gas flow confirmation unit 31 has a configuration in which, for example, pressure measurement units 35 and 36 are provided on the upstream and downstream sides of the orifice 34 that restricts the flow path of the inert gas supply passage 28. The flow rate of gas is calculated.

  The air component separator 29 has, for example, a known filter structure that extracts only nitrogen gas from the air, and is supplied with atmospheric pressure air or compressed air, and generates nitrogen gas from this air.

  In the main steam stop valve 1 configured as described above, when the actuator 14 pushes up the valve shaft 13 to release the valve body 9 from the valve seat 8, the valve seat 8 opens, and the main steam passes from the steam inlet passage 6 to the valve seat 8. And flows to the steam outlet passage 7 and further to the main steam inlet 2 of the steam turbine. This activates the steam turbine.

In the inert gas supply unit 32, as indicated by an arrow N, the nitrogen gas separated from the air in the air component separator 29 is supplied from the inert gas supply passage 28 to the valve shaft holding unit 12 by the air supply pump 30. The Therefore, the interior of the shaft hole 20 of the valve shaft holder 12 (the gap between the valve shaft 1 3) is filled with nitrogen gas, a portion of the nitrogen gas between the shaft hole 20 and the valve shaft 13 Out of the gap to the atmosphere (outside). As a result, the air around the main steam stop valve 1 cannot enter the valve shaft holder 12. The nitrogen gas that has not flowed out to the atmosphere is sucked into the ground steam condenser return passage 22.

  Therefore, for example, even if a flammable gas is contained in the ambient atmosphere of the main steam stop valve 1, the combustible gas can be prevented from being sucked into the main steam stop valve 1. In addition, sticking due to the active gas (oxygen or the like) contained in the air entering the inside of the valve shaft holding portion 12 and oxidizing the valve shaft holding portion 12 and the valve shaft 13 can be prevented.

  The inert gas supply passage 28 is connected to the atmosphere side of the ground steam condenser return passage 22 which is a leak fluid recovery passage. As described above, a negative pressure of, for example, about −0.02 barg is applied to the ground steam condenser return passage 22, and the nitrogen gas flowing through the inert gas supply passage 28 is, for example, about 0.1 barg than atmospheric pressure. High pressure is applied. For this reason, the nitrogen gas supplied from the inert gas supply unit 32 to the valve shaft holding unit 12 is likely to flow into the valve shaft holding unit 12 due to a pressure difference with the ground steam condenser return passage 22. Therefore, it is possible to reliably fill the interior of the valve shaft holding portion 12 with the inert gas and prevent the outside air or liquid from entering the main steam stop valve 1.

  Further, as described above, the pressure of the nitrogen gas flowing through the inert gas supply passage 28 is set to be higher than the atmospheric pressure, and the inert gas supply passage 28 is provided with a gas flow confirmation unit 31 for confirming the flow of nitrogen gas. It has been. For this reason, the circulation of nitrogen gas supplied to the main steam stop valve 1 can be confirmed, and the supply of nitrogen gas is prevented from stagnation, so that liquids such as outside air and rainwater are present inside the main steam stop valve 1. It can be prevented from entering.

  Furthermore, the inert gas can be procured at low cost by using nitrogen gas as the inert gas supplied into the valve shaft holding portion 12 of the main steam stop valve 1.

  In particular, since nitrogen gas is separated from the air by the air component separator 29 provided in the inert gas supply unit 32 and used as the inert gas, the nitrogen gas is removed from the air at the installation site of the main steam stop valve 1. It can be separated and used as an inert gas. Therefore, it is not necessary to purchase and transport pure nitrogen gas to the installation site of the main steam stop valve 1 or to replenish it, and it is possible to procure nitrogen gas as an inert gas easily and inexpensively.

  In this way, air around the main steam stop valve 1 and flammable gas are prevented from entering the inside of the valve shaft holding portion 12, and sticking due to oxidation in the vicinity of the valve shaft holding portion 12 is prevented. Therefore, the safety and reliability of the steam turbine can be improved.

[Second Embodiment]
FIG. 3 is a longitudinal sectional view of a steam control valve showing a second embodiment of the present invention.
Similar to the main steam stop valve 1 in the first embodiment, the steam control valve 41 is installed at a main steam inlet or the like of a steam turbine (not shown), and is a valve casing including a casing body 43 and a casing lid 44. 45. A valve chamber 46 (working fluid flow path) is provided inside the valve casing 45, and a steam inlet passage 47 (working fluid flow path) is connected horizontally to the valve chamber 46, and a steam outlet passage 48 (working fluid flow path). ) Is connected from below. In FIG. 3, the steam inlet passage 47 extends in a direction perpendicular to the paper surface.

  A valve seat 50 is provided at an opening portion of the steam outlet passage 48 in the valve chamber 46, and a valve shaft holding portion 51 is formed in the casing lid 44 so as to be positioned immediately above the valve seat 50. The valve shaft 52 is slidably held in the axial direction by the valve shaft holding portion 51, and a valve body 53 that opens and closes the valve seat 50 is connected to one end (lower end) of the valve shaft 52. An intermediate portion of the valve shaft 52 penetrates the valve shaft holding portion 51 and projects to the outside, and the other end (upper end) of the valve shaft 52 is pivoted on a rotating shaft 56 of a lever bracket 55 installed outside the casing lid 44. A middle portion of the supported opening / closing lever 57 is rotatably connected via a coupling 58. The free end of the open / close lever 57 is connected to an actuator (not shown).

  In the steam control valve 41, when an actuator (not shown) is operated, the open / close lever 57 rotates up and down around the rotation shaft 56 of the lever bracket 55, and the valve shaft 52 slides up and down to move the valve body 53. The valve seat 50 is moved up and down. When the valve body 53 moves upward, the valve seat 50 opens, and as shown by an arrow ST, main steam (working fluid) supplied to the steam turbine passes through the valve seat 50 from the steam inlet passage 47 through the valve chamber 46. To the steam outlet passage 48. The amount of the main steam is adjusted depending on the position of the valve body 53, that is, the amount of rotation of the opening / closing lever 57. In FIG. 3, the valve body 53 is closed.

  The valve shaft holding portion 51 is provided with a bearing-shaped guide bush 61 that supports the valve shaft 52. The valve shaft 52 is slidably inserted into a shaft hole 60 formed in the guide bush 61. Yes. A labyrinth structure is provided between the shaft hole 60 and the valve shaft 52 to reduce main steam leakage as much as possible. However, since the leakage cannot be completely prevented, the valve shaft is retained. The part 51 is provided with a leak fluid recovery passage.

  As the leakage fluid recovery passage, a seal steam receiver passage 62 and a ground steam condenser return passage 63 communicate with the valve shaft holding portion 51. In these passages 62 and 63, a part of the main steam in the valve chamber 46 passes between the valve shaft 52 and the guide bush 61 (shaft hole 60) and leaks to the atmosphere side (outside). By leaking the leaked steam (LS: leaked fluid) to a predetermined place using the pressure difference with the valve chamber 46, the leaked steam is prevented from leaking to the atmosphere side.

  A leak-off chamber 64 is provided at an intermediate portion of the guide bush 61, and independent leak-off chambers 65 and 66 are provided at the upper portion of the guide bush 61. The seal steam receiver passage 62 has one end connected to the leak-off chamber 64 and the other end connected to a seal steam receiver 68 (leak fluid recovery unit). The pressure of the seal steam receiver passage 62 is set to about 0.1 barg, for example.

  On the other hand, the ground steam condenser return passage 63 is provided on the atmosphere side (outside) with respect to the seal steam receiver passage 62, one end of which communicates with the leak-off chamber 65, and the other end of the ground steam condenser 69 ( Leakage fluid recovery unit). For example, a negative pressure of about −0.02 barg is applied to the ground steam condenser return passage 63.

  As indicated by an arrow LS in FIG. 3, leak steam (leak fluid) that has flowed from the valve chamber 46 to the leak-off chamber 64 through the valve shaft 52 and the guide bush 61 (shaft hole 60), The pressure difference leads to the seal steam receiver passage 62 and the ground steam condenser return passage 63 and flows to the seal steam receiver 68 or the ground steam condenser 69. As a result, the leaked steam is prevented from leaking from the valve shaft holding portion 51 to the atmosphere side.

  Further, when the steam does not leak from the valve chamber 46, the seal steam tends to flow out from the seal steam receiver passage 62 to the atmosphere side by the pressure of about 0.1 barg set in the seal steam receiver passage 62. However, since this seal steam flows to the ground steam condenser return passage 63 having a negative pressure and flows to the ground steam condenser 69, it does not leak to the atmosphere side.

  Further, the valve shaft holding part 51 is provided with an inert gas supply passage 71 so as to be connected to the atmosphere side (upper side) than the ground steam condenser return passage 63 which is a leak fluid recovery passage. One end of the inert gas supply passage 71 communicates with a leak-off chamber 66 formed in the upper portion of the guide bush 61, and the other end is connected to the air supply pump 73. An air component separator 72 and a gas flow confirmation unit 74 are connected to an intermediate part of the inert gas supply passage 71. The inert gas supply unit 75 includes an inert gas supply passage 71, an air component separator 72, an air supply pump 73, and a gas flow confirmation unit 74.

  The inert gas supply unit 75 supplies inert gas to the shaft hole 60 of the valve shaft holding unit 51 and supplies the inert gas into the shaft hole 60 in the same manner as the inert gas supply unit 32 of the first embodiment. It fills the active gas, and nitrogen gas is used as the inert gas. Nitrogen gas is supplied at a pressure higher than atmospheric pressure (for example, about 0.1 barg), and the circulation of the nitrogen gas can be confirmed by the gas circulation confirmation unit 74. Since the configuration of the gas flow confirmation unit 74 is the same as that of the gas flow confirmation unit 31 in the first embodiment, the same reference numerals are given to the respective components and the description thereof is omitted.

  Similar to the air component separator 29 in the first embodiment, the air component separator 72 has a known filter structure that extracts only nitrogen gas from the air, and supplies air at atmospheric pressure or compressed air. Nitrogen gas is generated from this air.

  In the steam control valve 41 configured as described above, in the inert gas supply unit 75, as indicated by an arrow N, the nitrogen gas separated from the air in the air component separator 72 is inert by the air supply pump 73. It is supplied from the gas supply passage 71 to the valve shaft holder 51. For this reason, the inside of the shaft hole 60 of the valve shaft holding portion 51 (a gap between the valve shaft 52) is filled with nitrogen gas, and a part of this nitrogen gas is a clearance between the shaft hole 60 and the valve shaft 52. Out to the atmosphere side (outside). Thereby, the air around the steam control valve 41 cannot enter the valve shaft holding portion 51. The nitrogen gas that has not flowed out to the atmosphere side is sucked into the ground steam condenser return passage 63.

  Therefore, for example, even if combustible gas is contained in the atmosphere around the steam control valve 41, it is possible to prevent the combustible gas from being sucked into the steam control valve 41. Moreover, sticking due to the active gas (oxygen or the like) contained in the air entering the inside of the valve shaft holding portion 51 and oxidizing the valve shaft holding portion 51 and the valve shaft 52 can be prevented.

  Since the inert gas supply passage 71 is connected to the atmosphere side with respect to the ground steam condenser return passage 63 which is a leakage fluid recovery passage, nitrogen supplied from the inert gas supply portion 75 to the valve shaft holding portion 51 is supplied. The gas easily flows into the valve shaft holder 51 due to the pressure difference with the ground steam condenser return passage 63. Therefore, it is possible to reliably fill the inside of the valve shaft holding portion 51 with the inert gas and prevent the outside air or liquid from entering the inside of the steam control valve 41.

  As described above, the valve casings 5 and 45 according to the embodiment of the present invention, the steam valves (the main steam stop valve 1, the steam control valve 41, etc.) provided with the same, the steam turbine provided with the steam valves, and the valve casing According to the atmospheric gas intrusion prevention method, the gas around the steam valves 1 and 41 is prevented from entering the valve shaft holders 12 and 51, and the risk of ignition is eliminated, and the active gas contained in the air The vapor valves 1 and 41 are prevented from sticking by preventing (oxygen or the like) from entering the valve shaft holding parts 12 and 51 and oxidizing the valve shaft holding parts 12 and 51 and the valve shafts 13 and 52, etc. Sex can be kept long.

  Moreover, by providing such a steam valve 1, 41 in the steam turbine, it is possible to prevent the occurrence of ignition and sticking in the vicinity of the valve shaft holding parts 12, 51, thereby improving the safety and reliability of the steam turbine. .

  It should be noted that the present invention is not limited to the configuration of the above-described embodiment, and can be appropriately modified or improved within a scope not departing from the gist of the present invention. Are also included in the scope of rights of the present invention.

  For example, in the above embodiment, the example in which the present invention is applied to the steam valve (1, 41) provided in the steam turbine has been described. However, the present invention can be applied to, for example, a gas valve.

1 Main steam stop valve (valve)
2 Main steam inlet 5, 45 Valve casing 6, 47 Steam inlet passage (working fluid passage)
7, 48 Steam outlet passage (working fluid passage)
8,50 Valve seat (flow control member)
9,53 Valve body (flow rate control member)
12, 51 Valve shaft holder 13, 52 Valve shaft (flow rate control member)
20, 60 Shaft hole 21, 62 Seal steam receiver passage (leak fluid recovery passage)
22, 63 Ground steam condenser return passage (leak fluid recovery passage)
24, 68 Sealed steam receiver (leak fluid recovery part)
25, 69 Grand steam condenser (leak fluid recovery part)
28, 71 Inert gas supply passages 29, 72 Air component separators 31, 74 Gas flow confirmation unit 32, 75 Inert gas supply unit 41 Steam control valve (steam valve)
46 Valve chamber (steam passage working fluid passage)
LS leak steam (leak fluid)
N Nitrogen (inert gas)
ST Main steam (working fluid)

Claims (7)

A working fluid flow path through which a working fluid having a pressure higher than atmospheric pressure flows;
A valve shaft holding portion that houses at least a valve shaft of a flow rate control member that controls the flow rate of the working fluid inside the working fluid flow channel and has one end connected to the working fluid flow channel,
The valve shaft holding portion includes an inert gas supply portion that supplies an inert gas to the shaft hole of the valve shaft,
The valve shaft holding part is provided with a leak fluid recovery passage that guides leaked fluid leaking from the inside of the working fluid channel to the leaked fluid recovery unit using a pressure difference with the working fluid channel,
The inert gas supply unit is connected to the atmosphere side with respect to the leak fluid recovery passage, and allows a part of the inert gas to flow out from the other end side of the valve shaft holding unit to the outside of the valve shaft holding unit. A valve casing characterized by that.   2. The valve casing according to claim 1, wherein the inert gas is supplied at a pressure higher than atmospheric pressure, and a gas flow confirmation unit for confirming the flow of the inert gas is provided.   The valve casing according to claim 1 or 2, wherein the inert gas is nitrogen gas.   The said inert gas supply part is connected to the air component separator which isolate | separates nitrogen gas from the air, The nitrogen gas isolate | separated in this air component separator is used as said inert gas. Valve casing.   A valve comprising the valve casing according to claim 1.   A turbine apparatus comprising the valve according to claim 5. A working fluid flow path through which the working fluid flows;
A valve shaft holding portion that accommodates at least a valve shaft of a flow rate control member that controls the flow rate of the working fluid inside the working fluid flow channel and has one end connected to the working fluid flow channel. An atmosphere gas intrusion prevention method for a valve casing,
Supplying an inert gas to a shaft hole of the valve shaft in the valve shaft holding portion;
The valve shaft holding portion is provided with a leak fluid recovery passage that guides leaked fluid leaking from the inside of the working fluid flow channel to the leak fluid recovery portion using a pressure difference with the working fluid flow channel,
Supplying the inert gas to a position closer to the atmosphere than the leaked fluid recovery passage, and causing a part of the inert gas to flow out of the valve shaft holding portion to the outside of the valve shaft holding portion; A method for preventing atmospheric gas from entering a valve casing.

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