JP2003148109A - Deformation amount adjusting device for steam turbine casing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deformation amount adjusting device for a steam turbine casing which prevents contact between a turbine rotor and a blade ring of a stator blade and degradation due to gap increase between the turbine rotor and the blade ring, by avoiding the so-called warping phenomenon of the turbine casing being bent during turbine stoppage or operation by a simple structure, with the small number of components, at a low device cost and without provid ing a particular device. SOLUTION: The steam turbine is composed so that gland steam is lead into a gland steam chest formed in an end part of the turbine casing composed of an upper casing and a lower casing, and the gland steam is fed to a gland part carrying out fluid sealing between a turbine casing interior and the outside air. It is characterized by that it has a steam passage provided along an outer wall outer face of the lower casing and communicated with the gland steam chest and it is provided with a lower casing heating means of heating the lower casing by the gland steam flowing through the steam passage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention introduces gland steam into a gland steam chamber formed at an end of a turbine casing formed by an upper casing and a lower casing, and the gland steam is supplied to the turbine casing. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine configured to supply a gland portion that performs fluid sealing between the inside and the outside air, and particularly to a deformation adjusting device for a turbine casing in a high and medium pressure turbine.

[0002]

2. Description of the Related Art FIG. 5 is a cross-sectional view of a main portion along a turbine shaft center line showing the vicinity of a fluid seal portion formed by gland steam in a high and intermediate pressure integrated steam turbine. In the figure, 1a is an upper compartment, 1 is a lower compartment that is coupled to the upper compartment 1a by a plurality of bolts on a coupling surface on the turbine axis, and is composed of the upper compartment 1a and the lower compartment 1. It constitutes the turbine casing. Reference numeral 2 is a turbine rotor, and 4 is a plurality of moving blades fixed to the outer peripheral portion of the turbine rotor at equal intervals along the circumferential direction. Reference numeral 5 denotes a stationary blade arranged on the upstream side of each of the plurality of moving blades 4 and attached to the turbine casing.

Reference numerals 6 and 6 are gland seal fins formed at the ends of the turbine casing, and 3 is a gland steam chamber formed between the gland seal fins 6 and 6. A gland steam is introduced into the gland steam chamber 3 from an auxiliary boiler (not shown), and the gland steam is supplied to the gland seal fins 6 to seal the fluid between the passenger compartment 7 and the outside air. It is carried out. The steam and the like (ground steam, intruding air, leaking steam) in the gland steam chamber 3 are sucked into a gland steam condenser (not shown) through an exhaust pipe 12 connected to the outlet side of the gland steam chamber 3. It Reference numeral 13 denotes an exhaust pump provided in the exhaust pipe 12 for exhausting the steam or the like.

In such a high / medium pressure integrated steam turbine, since there is no flow of steam in the vehicle interior section 7 after the turbine is stopped, hot air is generated in the upper half of the vehicle interior section 7 by natural convection in the vehicle interior section 7. And the cooling rate of the upper casing 1a becomes slower than that of the lower casing 1, so that the temperature of the upper casing 1a becomes higher than that of the lower casing 1. For this reason, the thermal expansion on the high temperature upper compartment 1a side becomes larger than the thermal expansion on the low temperature lower compartment 1 side, so that a phenomenon in which the turbine casing is curved in a convex shape, so-called cat warp phenomenon occurs. When such a cat warp phenomenon occurs, the lower gap between the outer circumference of the turbine rotor 2 that is a rotating body and the inner circumference of the blade ring of the stationary blade 5 that is a stationary body is smaller than the set distance, and the turbine rotor 2 and There is a risk of contact with the blade ring of the stationary blade 5. Therefore, conventionally, in order to avoid the contact, a means of setting a large gap between the outer circumference of the turbine rotor 2 and the inner circumference of the blade ring of the stationary blade 5 is used. We will see the occurrence of performance deterioration due to increased steam leakage from the gap.

As a means for preventing the occurrence of cat warp in the turbine casing, for example, the inventions of JP-A-8-312306 and JP-A-9-114506 are provided. In JP-A-8-312306, a plurality of cooling passages provided in the outer peripheral portion of the upper casing, a cooling medium passage connected to the passages, a control valve provided in the passage, and an upper casing are provided. And a metal thermometer provided on the outer periphery of the lower casing, the temperature of the upper casing and the lower casing are detected by the metal thermometer and sent to a control valve, and the upper and lower casings are controlled by the control valve. It is configured to control the flow rate of the cooling medium that cools the upper compartment so as to eliminate the temperature difference between the metal temperatures of the compartment. Further, in Japanese Patent Laid-Open No. 9-114506, a heat transfer tube through which a fluid for adjusting the vehicle compartment temperature flows is fixed to the outer peripheral surfaces of the upper and lower vehicle compartments, and the inside of the heat transfer tube is fixed during startup and operation of the turbine. The high temperature fluid such as steam is used to heat the outer periphery of the passenger compartment on the low temperature side to make the passenger compartment temperature uniform in the thickness direction.

[0006]

As described above, in the steam turbine, the phenomenon in which the turbine casing is curved in a convex shape, that is, the so-called cat-warp phenomenon occurs remarkably after the turbine is stopped. However, in JP-A-8-312306, a cooling medium such as cooling air is introduced from the outside of the steam turbine into a plurality of cooling passages provided in the outer peripheral portion of the upper casing to increase the temperature after the turbine is stopped. The upper compartment is cooling. Therefore, in the invention, the cooling medium for cooling the upper casing is required after the turbine is stopped, and a special device such as a cooling medium supply source and piping is required to supply the cooling medium when the turbine is stopped. Therefore, the structure is complicated, the number of parts is increased, and the device cost is increased.

Further, in the invention of Japanese Patent Application Laid-Open No. 9-114506, at the time of starting and operating the turbine, the outer temperature of the passenger compartment, which becomes low in temperature, is heated by using reheat steam or the like to keep the passenger compartment temperature in the thickness direction. Since it is made uniform, it is impossible to prevent the cat warp phenomenon when the turbine is stopped.

In view of the problems of the prior art, the present invention has a simple structure without a special device, a small number of parts, and a low device cost, so that the turbine casing is curved when the turbine is stopped and in operation. Phenomenon By preventing the occurrence of so-called cat warp phenomenon, it is possible to prevent the occurrence of contact between the turbine rotor and the blade ring of the stationary blade, and prevent the occurrence of performance deterioration due to the increase in the gap between the turbine rotor and the blade ring of the stationary blade It is an object of the present invention to provide a steam turbine casing deformation amount adjusting device that can be used.

[0009]

In order to solve the above problems, the present invention provides a gland formed at an end portion of a turbine casing constituted by an upper casing and a lower casing, as an invention according to claim 1. In a steam turbine configured to introduce gland steam into the steam chamber and to supply the gland steam to a gland part that performs fluid sealing between the inside of the turbine casing and the outside air, the gland steam is provided along the outer surface of the outer wall of the lower casing. A steam turbine vehicle having a steam passage that is communicated with the ground steam chamber and that includes a lower casing heating means that heats the lower casing by the ground steam flowing through the steam passage. We propose a device for adjusting the amount of deformation of a room.

The invention according to claims 2 to 5 relates to a specific structure of the lower casing heating means, and the invention according to claim 2 is the same as in claim 1, wherein the lower casing heating means includes the steam passages. It is characterized in that it is formed in the turbine axial direction integrally with the lower casing along the outer wall of the lower casing. In claim 2, preferably, as in claim 3, the lower casing heating means includes a steam reservoir communicating with the gland steam chamber, and the plurality of steam passages are diverted from the steam reservoir to form a plurality of turbines in the steam passage. They are arranged side by side in the axial direction.

According to a fourth aspect of the present invention, in the first aspect, the lower casing heating means is provided with a steam pipe fixed to an outer wall of the lower casing and extending in a turbine axial direction, and an inside of the steam pipe. It is characterized in that the steam passage is formed in. In claim 4, preferably as in claim 5,
The lower casing heating means includes a vapor reservoir communicating with the gland vapor chamber, a plurality of the vapor pipes are fixed to an outer wall of the vapor reservoir, and the steam is divided into the vapor pipes in each of the vapor pipes to divide the vapor into the vapor reservoir. Install steam passages in parallel.

According to the invention, after the turbine is stopped, the ground steam is supplied from the auxiliary boiler or the like to the gland portion (grand steam chamber) to maintain the vacuum in the turbine casing, and the outside air is prevented from entering. This ground steam is introduced into the steam passage of the lower casing heating means provided in the turbine axial direction along the outer surface of the outer wall of the lower casing. When the ground steam having a steam temperature of about 200 ° C. flows in the steam passage, the lower vehicle compartment, which has a temperature lower than that of the upper vehicle compartment after the turbine is stopped, is heated by the ground steam, so that the lower vehicle The temperature of the compartment is raised, and the temperature difference between the upper compartment and the lower compartment is eliminated to make it uniform. As a result, there is no difference in thermal expansion between the upper casing side and the lower casing side, and the phenomenon in which the turbine casing is curved in a convex shape due to the difference in thermal expansion, so-called cat warping, is avoided. During operation of the steam turbine, since the ground steam is supplied from the turbine casing to the gland portion (grand steam chamber), by introducing this gland steam into the steam passage of the lower casing heating means in the same manner as described above, The cat warp phenomenon can be avoided.

Therefore, according to the invention, after the turbine is stopped, the ground steam is introduced into the steam passage of the lower casing heating means to heat the lower casing lower in temperature than the upper casing by the ground steam to heat the lower casing. By raising the temperature of the passenger compartment to eliminate and equalize the temperature difference between the upper passenger compartment and the lower passenger compartment, the cat warp phenomenon caused by the difference in thermal expansion between the upper passenger compartment side and the lower passenger compartment side is prevented. It can be avoided. Therefore, by using the ground steam that is supplied even after the turbine is stopped, the steam passage for the passage of the ground steam is provided along the outer surface of the outer wall of the lower compartment, which does not require a special device and has a very simple structure. With a low-cost device with a small number of parts, the cat warp phenomenon can be avoided.
Further, even when the steam turbine is in operation, it is possible to avoid the occurrence of the cat warp phenomenon by introducing the ground steam supplied from the turbine compartment to the ground steam compartment into the steam passage of the lower compartment heating means. As a result, it is possible to avoid the occurrence of contact between the outer circumference of the turbine rotor, which is a rotating body, and the inner circumference of the blade ring of the stationary blade, which is a stationary body, and prevent the contact between the turbine rotor and the blade ring of the stationary blade. It is not necessary to set a large gap value, and it is possible to prevent the performance from deteriorating due to the increase in the set gap.

According to the present invention, the steam reservoir and the steam passage of the lower casing heating means can be integrally formed with the lower casing, so that the number of turbine manufacturing steps is not increased. The occurrence of the cat warp phenomenon can be avoided.

According to the present invention, the existing steam turbine can be constructed by simply fixing the steam pipe of the lower casing heating means to the outer wall of the lower casing by welding, brazing or the like. The deformation amount adjusting device for the turbine casing that can avoid the occurrence of the warp phenomenon can be easily configured.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention thereto, unless there is a specific description, and are merely illustrative examples. Nothing more.

FIG. 1 is a sectional view of a main part along a turbine axis showing a turbine casing deformation amount adjusting device in a high / intermediate pressure integrated steam turbine according to a first embodiment of the present invention, and FIG. FIG. 9 is a sectional view taken along line AA of FIG. FIG. 3 is a view corresponding to FIG. 1 showing a second embodiment of the present invention, and FIG. 4 is a sectional view taken along line BB of FIG.

1 and 2 showing the first embodiment, 1a
Is an upper compartment, and 1 is a lower compartment that is connected to the upper compartment 1a by a plurality of bolts on a connecting surface on the turbine axis.
The upper casing 1a and the lower casing 1 form a turbine casing. Reference numeral 2 is a turbine rotor, and 4 is a plurality of moving blades fixed to the outer peripheral portion of the turbine rotor at equal intervals along the circumferential direction. Reference numeral 5 denotes a stationary blade arranged on the upstream side of each of the plurality of moving blades 4 and attached to the turbine casing. Further, 7 is the inside of the vehicle compartment, and 02 is the turbine rotation center. 6, 6
Is a gland seal fin formed at the end of the turbine casing, and 3 is a gland steam chamber formed between the gland seal fins 6, 6. The above basic configuration is the same as that of the conventional technique shown in FIG.

Reference numeral 03 denotes a steam inlet of the gland steam chamber 3. Gland steam is introduced into the gland steam chamber 3 from an auxiliary boiler (not shown) via the steam inlet 03, and the gland steam is sealed by the gland seal. By supplying the fins 6 to the inside, the fluid is sealed between the vehicle interior 7 and the outside air. Reference numeral 11 is a steam passage formed by integral casting with the lower casing 1. The steam passage 11 is
A plurality of them are formed in parallel with each other in the turbine axial direction along the vehicle outer wall 01 of the lower vehicle compartment 1 and along the peripheral wall of the vehicle outer wall 01 as shown in FIG. Reference numeral 10 denotes a vapor reservoir formed integrally with the lower casing 1 on the upstream side of the vapor passage 11, and although the vapor reservoir 10 is not shown in the drawing, all of the vapor reservoir 10 to the vapor passage 11 are not shown. It extends in the circumferential direction of the lower compartment 1 so that it can be connected to the inlet.

A steam passage 14 is provided on the inlet side of the steam reservoir 10.
Through the gland steam chamber 3. Further, the outlet sides of the plurality of steam passages 11 are joined to each other and connected to the discharge pipe 12, and the steam and the like (ground steam, invading air, leaked steam) passing through the steam passages 11 pass through the discharge pipes 12 to the ground. It is sucked into a steam condenser (not shown). 1
Reference numeral 3 is an exhaust pump provided in the exhaust pipe 12 for exhausting the steam and the like.

In the first embodiment, after the turbine is stopped, the ground steam is supplied from the auxiliary boiler or the like through the steam inlet 03 to the ground steam chamber 3 of the gland portion to maintain the vacuum in the turbine casing, and the ground steam is supplied to the gland steam. By supplying to the 6 parts of the gland seal fin,
A fluid seal is provided between the vehicle interior 7 and the outside air to prevent the outside air from entering. And 2 in the grand steam room 3
The ground steam of about 00 ° C. is introduced into the steam reservoir 10 through the steam passage 14 and then spreads in the steam reservoir 10 in the circumferential direction to flow into the plurality of steam passages 11, and the steam temperature of about 200 ° C. The lower casing 1 is heated by the ground steam flowing in the steam passage.

After the turbine is stopped, the lower casing 1 having a temperature lower than that of the upper casing 1a is heated by the gland steam to raise the temperature of the lower casing 1a and the upper casing 1a.
And the temperature difference between the lower casing 1 and the lower casing 1 are eliminated and equalized. As a result, the difference in thermal expansion between the upper casing 1a side and the lower casing 1 side is eliminated, and the phenomenon in which the turbine casing is curved in a convex shape due to the difference in thermal expansion, so-called cat warping, is avoided. . During the operation of the steam turbine, the ground steam is supplied from the turbine casing to the gland portion (grand steam chamber 3). Therefore, the ground steam should be introduced into the steam passage 11 on the lower casing 1 side as described above. As a result, the cat warp phenomenon can be avoided.

As described above, according to this embodiment, by using the gland steam that is supplied even after the turbine is stopped, the gland steam flow passage 10 is formed along the outer surface of the outer wall 01 of the lower casing 1. It is possible to avoid the occurrence of the cat warp phenomenon with a very simple structure of providing the above structure, and to introduce the grand steam supplied from the turbine casing to the grand steam chamber 3 into the steam passage 11 even when the steam turbine is operating. Therefore, the occurrence of the cat warp phenomenon can be avoided.

In the second embodiment shown in FIGS. 3 to 4, 20 is a steam pipe fixed to the outer surface of the outer wall 01 of the lower casing 1 by welding, brazing, etc.
Has become. The steam pipe 20 extends in the turbine axis direction along the outer surface of the outer casing wall 01 of the lower casing 1, and as shown in FIG.
As shown in FIG. 2, a plurality of them are fixed in parallel along the circumferential direction of the vehicle compartment outer wall 01. Reference numeral 23 denotes a vapor reservoir, which is provided in the same case 03a as the grand vapor chamber 3 in the same manner.
Is formed in communication with. The inlet side of the steam pipe 20 is fixed to the case 03a by a bolt (not shown), and the inlet of the steam passage 21 in the steam pipe 20 communicates with the steam reservoir 23 via a steam extraction port 22. Other configurations and operations are similar to those of the first embodiment, and the same members as those of the first embodiment are designated by the same reference numerals.

In the second embodiment, even in the existing steam turbine, the apparatus can be equipped only by fixing the plurality of steam pipes 20 to the outer wall 01 of the lower casing 1 by welding, brazing, etc. Even for a steam turbine, it is possible to easily configure a deformation adjusting device for the turbine casing that can avoid the occurrence of the cat warp phenomenon.

[0026]

As described above, according to the present invention, after the turbine is stopped, the ground steam is introduced into the steam passage of the heating means for the lower passenger compartment, and the lower passenger compartment has a lower temperature than the upper passenger compartment due to the ground steam. By heating the lower compartment to eliminate and equalize the temperature difference between the upper compartment and the lower compartment, the cat warp due to the difference in thermal expansion between the upper compartment and the lower compartment. It is possible to avoid the occurrence of the phenomenon. Therefore, by using the ground steam that is supplied even after the turbine is stopped, the steam passage for the passage of the ground steam is provided along the outer surface of the outer wall of the lower compartment, which does not require a special device and has a very simple structure. The occurrence of the cat warp phenomenon can be avoided with a low-cost device having a small number of parts. Further, even when the steam turbine is in operation, it is possible to avoid the occurrence of the cat warp phenomenon by introducing the ground steam supplied from the turbine compartment to the ground steam compartment into the steam passage of the lower compartment heating means. As a result, it is possible to avoid the occurrence of contact between the outer circumference of the turbine rotor, which is a rotating body, and the inner circumference of the blade ring of the stationary blade, which is a stationary body, and prevent the contact between the turbine rotor and the blade ring of the stationary blade. It is not necessary to set the gap value to a large value, and it is possible to prevent performance deterioration due to the increase in the set gap.

According to the present invention, the steam reservoir and the steam passage of the lower casing heating means can be integrally formed with the lower casing, so that the number of turbine manufacturing steps is not increased. The occurrence of the cat warp phenomenon can be avoided.

Further, according to the present invention, even in the existing steam turbine, the steam pipe of the lower casing heating means is fixed to the outer wall of the lower casing only by welding, brazing or the like. The deformation amount adjusting device for the turbine casing that can avoid the occurrence of the warp phenomenon can be easily configured.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts along a turbine axis for showing a deformation adjusting device for a turbine casing in a high and intermediate pressure integrated steam turbine according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a view corresponding to FIG. 1 and showing a second embodiment of the present invention.

FIG. 4 is a sectional view taken along line BB of FIG.

FIG. 5 is a cross-sectional view of a main part along a turbine axis showing the vicinity of a fluid seal part by gland steam in a conventional high and intermediate pressure integrated steam turbine.

[Explanation of symbols]

1 Lower cabin 01 Exterior wall 1a Upper compartment 2 turbine rotor 3 Grand steam room 6 Grand seal fin 7 Car interior 10,23 Steam reservoir 11, 14, 21 Steam passage 12 discharge pipe 20 steam pipe

Claims (5)

[Claims] 1. A gland steam is introduced into a gland steam chamber formed at an end portion of a turbine casing formed by an upper casing and a lower casing, and the gland steam is used as a fluid between the inside of the turbine casing and the outside air. In a steam turbine configured to supply to a gland portion that performs sealing, the steam turbine has a steam passage that is provided along an outer surface of an outer wall of the lower vehicle compartment and communicates with the gland steam chamber, and flows through the steam passage. A deformation amount adjusting device for a steam turbine casing, comprising: a lower casing heating means for heating the lower casing with the ground steam. 2. The lower casing heating means is characterized in that the steam passage is integrally formed with the lower casing along the outer wall of the lower casing in the turbine axial direction.
A steam turbine casing deformation amount adjusting device as described. 3. The lower casing heating means includes a steam reservoir communicating with the ground steam chamber, and the plurality of steam passages are diverted from the steam reservoir and arranged in parallel in a turbine axial direction. The deformation amount adjusting device for a steam turbine casing according to claim 2, wherein: 4. The lower casing heating means includes a steam pipe fixed to an outer wall of the lower casing and extending in a turbine axis direction, and the steam passage is formed inside the steam pipe. The deformation amount adjusting device for a steam turbine casing according to claim 1, wherein: 5. The lower casing heating means includes a vapor reservoir communicating with the gland vapor chamber, a plurality of the vapor pipes are fixed to an outer wall of the vapor reservoir, and the steam is provided in each of the vapor pipes. The deformation amount adjusting device for a steam turbine casing according to claim 4, wherein the steam passages are branched from a reservoir and the steam passages are arranged in parallel.