JPH11257013A - Seal device for steam turbine and the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize steam leak by disposing a spring member around a guide pin connecting a seal ring bearing and a seal ring and energizing the seal ring radially outward while communicating the radially outward pressure operating surface of the seal ring with high pressure side such as a steam turbine. SOLUTION: Guide pins 16 having round shape are disposed on a seal ring 2 it a distance from each other in circumferential direction and they are tightened onto a guide plate 9 by means of bolt. A disc spring 8a is disposed around the guide pin 16, and a spherical bearing 15 for receiving the disc spring 8a is formed outside the disc spring 8a. Further, a press plate 17 fixed on the seal ring pushes the spherical bearing 15 to construct this portion as a set. A vapor operating surface 10 is formed on the outer periphery of the seal ring 2. The operating surface 10 is communicated to the high pressure side of the steam turbine through a plurality of bypass holes 14 provided in the seal ring 2 in circumferential direction. At rating, the seal ring 2 is pressed by outside and inside differential pressure to be in contact with a seal ring datum plane 4 so as to ensure a minimum clearance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device provided in a rotating part of a steam turbine or the like.

[0002]

2. Description of the Related Art The structure of a sealing device provided between a casing end and a rotor end in a conventional steam turbine will be described with reference to FIGS.

[0003] The casing end portion 03 of the steam turbine and the rotor 01
Between the end of the seal ring receiver 0
The seal ring 02 supported by the seal ring 7 is interposed, and is sealed by a seal fin 05 implanted on the inner peripheral surface of the seal ring 02 by caulking or the like.

[0004] However, the steam in the cabin is reduced by the seal ring 0.
2 leaks out of the seal ring 02 from the clearance formed between the inner diameter of the seal fin 05 and the outer diameter of the rotor 01.

In order to reduce the amount of the leakage, the clearance is made as small as possible, and a leaf spring 06 is provided between the seal ring 02 and the seal ring receiver 07 so that even if it comes into contact with the rotor 01, no problem occurs. Has been put.

That is, the seal ring 02 is normally pushed inward in the radial direction by the urging force of the leaf spring 06 to keep the clearance between the rotor 01 and the seal fins 05 at a minimum, and the seal fins 05 come into contact with the rotor 01. In such a case, the seal ring 02 itself moves radially outward to have a seal structure in which the seal fins 05 are prevented from being worn or damaged.

As shown in FIGS. 10 and 11, one end of the structure is fixed to the seal ring 02 with a bolt or the like, the other end is opened, and the center is curved outwardly. The positioning and locking portion of the seal ring 02 abuts against the seal ring reference surface 04 by the leaf spring 06, and the seal fin 05
It is set so that the clearance between the motor and the rotor 01 is kept constant.

[0008]

In the prior art constructed as described above, in the transitional period of the start / stop of the turbine, the heat elongation of the casing is not uniform, and the rotor 01 sinks in relation to the bearing. The clearance between the inner diameter of the seal fins 05 and the outer diameter of the rotor 01, which is set in consideration of the insertion and the elongation of the rotor 01 due to the centrifugal force, is maintained. There is also a possibility that abrasion or damage may occur, or steam leakage may occur from the clearance to cause a disadvantage that turbine performance is reduced.

Also, the leaf spring 06 is provided in FIGS.
As can be understood from the description of 1, the shape is long in the circumferential direction and short in the axial direction, so that the degree of freedom of response to the axial deviation of the seal ring receiver 07 or the like with which the leaf spring 06 comes in contact. Is small and lacks stability.

On the other hand, when the turbine enters a steady operation, the heat elongation of the casing is made uniform over time, the floating of the rotor shaft is made constant, and the clearance is kept constant in conformity with the set state. However, the instability with respect to the aforementioned axial deviation still remains.

The present invention solves the above-mentioned problems of the prior art, reduces the clearance at a fixed interval as much as possible, reduces the leakage of steam from the clearance, and maintains the stability of the sealing function to achieve overall turbine performance. It is an object of the present invention to provide a product which aims to improve the quality.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a seal ring having a seal fin extending toward an outer diameter of a rotor, and a seal ring holding the seal ring. A guide pin for connecting the seal ring receiver and the seal ring to guide the radial movement of the seal ring; and a guide pin disposed around the guide pin for urging the seal ring outward in the radial direction. The present invention is to provide a sealing device for a steam turbine or the like provided with a spring member and a pressure acting surface formed radially outward of the seal ring and communicating with a high pressure side of the steam turbine or the like.

That is, according to the present invention, a spring member is provided around a guide pin connecting the seal ring receiver and the seal ring, and the spring member is urged radially outward by the spring member. On the other hand, since the pressure acting surface formed radially outward of the seal ring in opposition thereto communicates with the high pressure side of the steam turbine or the like, the spring is not activated when there is no acting pressure on the pressure acting surface. The seal ring is pushed radially outward by the urging force of the member to secure and maintain the clearance, and at the rated pressure when pressure is generated in the steam turbine, the seal ring is pushed radially inward by the steam pressure acting on the pressure action surface Is kept to a minimum, thereby maintaining the stability of the sealing function in the clearance portion and improving the turbine performance.

Further, the present invention provides a sealing device in a steam turbine or the like in which the spring member is formed by a disc spring or a coil spring.

That is, according to the present invention, since the spring member disposed around the guide pin is formed of a disc spring or a coil spring, the spring constant around the guide pin is equal, and the circumferential direction of the turbine is equal to that of the guide pin. In addition to this, a uniform biasing force is applied not only in the axial direction but also in the axial direction, so that even if a circumferential or axial force acts on the seal ring, the sealing function is properly maintained and the stability is further improved.

Further, according to the present invention, the seal ring is divided into a plurality in the circumferential direction, and each divided piece is connected to the seal ring receiver by at least two round shaft-shaped guide pins or a single rectangular shaft-shaped guide pin. To provide a sealing device for a steam turbine or the like.

That is, according to the present invention, the seal ring divided into a plurality in the circumferential direction has two round guide pins or one rectangular guide pin per seal ring.
Since it is configured to be guided and supported individually, in the case of a round shaft-shaped guide pin, two-point support by two guide pins allows stable positioning without movement in the axial direction. , The stability of the sealing function is obtained, and in the case of a rectangular shaft-shaped guide pin, by using a rectangular surface, stable support is achieved with a simple configuration despite the single-point support, This is to ensure reliable sealing.

Further, in the present invention, the seal ring is divided into a plurality of parts in a circumferential direction, and the seal ring corresponding to the horizontal portion is provided with a leaf spring between the seal ring and the seal ring receiver instead of the guide pin. The present invention provides a sealing device for a steam turbine or the like held by the above.

That is, according to the present invention, the structure of the support portion of the seal ring divided in the circumferential direction of the steam turbine is as follows:
The ones arranged on the horizontal part shall incorporate leaf springs,
The parts arranged in the upper and lower parts and the like are used separately from those using the guide pins, so that the variety of design and production can be widened and the cost can be reduced.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. Reference numeral 2 denotes a seal ring. The seal ring 2 is divided into three in the direction of the upper half of the turbine, divided into three in the direction of the lower half opposed thereto, and divided into six in the circumferential direction of the rotor 1.

A plurality of seal fins 5 are fixed to the inner peripheral surface of each seal ring 2 by caulking, and a clearance is formed between the tip of the seal fin 5 and the peripheral surface of the rotor 1. ing.

One of the plurality of divided seal rings 2
FIG. 2 is a side view of a portion viewed in the direction of arrows AA in FIG. 1A. In the seal ring 2, a round shaft-shaped guide pin 16 is arranged at two positions separated in the circumferential direction. Guide pin 1
The disc spring 8a, the spherical seat 15, and the presser plate 17 are assembled as a set for each 6 pieces.

That is, the guide pin 16 is fastened to the guide plate 9 by a bolt 9a, a disc spring 8a is arranged around the guide pin 16, and a spherical seat 15 for receiving the disc spring 8a is formed outside the guide spring 8a. Seal ring 2 with bolt 17a
This part is configured as a set by pressing with a holding plate 17 fixed to the base member, and insertion and assembly are performed from the horizontal direction in the state set in this manner.

A steam pressure action surface 10 is formed on the outer peripheral side of the seal ring 2, and an appropriate position is selected in the seal ring 2 in the circumferential direction and a plurality of bypass holes 14 are provided in a high pressure side of the steam turbine. The passage which communicates with is formed.

In this embodiment constructed as described above, when starting and stopping, since there is no pressure difference between the high pressure side and the low pressure side, it is mounted in the seal ring 2 as shown in FIG. The gap between the rotor 1 and the seal fins 5 is widened by the steam pressure acting surface 10 of the seal ring 2 being in contact with the receding surface of the seal ring 2 by the disc spring 8a.

At the time of rating, since the cabin pressure increases and there is a pressure difference between the high pressure side and the low pressure side, as shown in FIG. When the pressure on the high pressure side communicates with the surface 10, the side surface of the seal ring 2 contacts the thrust receiving surface 11 in the axial direction,
In the radial direction, the clearance between the rotor 1 and the seal fins 5 is set by the movement of the seal ring 2 toward the rotor 1 and the contact of the seal ring 2 with the seal ring reference surface 4.

In some cases, such as during the start of the turbine, the pressure acting on the vapor pressure acting surface 10 may not act uniformly in the circumferential direction. In this case, the seal ring 2 is constituted by six parts in the circumferential direction. For this reason, there is a possibility that the seal rings 2 may move apart from each other and the joints 13 between the adjacent seal rings 2 may be twisted.
6 are mounted at two locations in the circumferential direction, are positioned and held by the guide plate 9, and two sets of disc springs 8a and spherical seats 15 are provided on both sides. The twisting is prevented, and the seal ring 2 is kept stable in the circumferential direction.

Further, since the disc spring 8a has the same spring constant in the circumferential direction of the guide pin 16, there is no disadvantage that the spring is weak in the axial direction like a leaf spring having a small spring constant in the turbine axial direction. As a result, the seal ring 2 can be smoothly moved in the radial direction.

Next, a second embodiment of the present invention will be described with reference to FIG.
A description will be given based on FIGS. In the present embodiment, a coil spring 8 is used instead of the disc spring 8a in the first embodiment.
b, and the other structure is exactly the same as that of the first embodiment. Therefore, the same parts are denoted by the same reference numerals in the drawings, and the redundant description is omitted. .

In the present embodiment, the coil spring 8b
Around the guide pin 16 so that
Similar to the disc spring 8a in the first embodiment, the same spring constant is obtained in the circumferential direction of the guide pin 16 as in the circumferential direction of the turbine and the axial direction, so that both forces can be equally dealt with.

That is, according to the present embodiment, similarly to the case of the disc spring 8a, the seal ring 2 is appropriately coped with the axial force applied to the seal ring 2 in the same manner as the circumferential force. It is intended to securely support and maintain the stability of the sealing function.

Next, a third embodiment of the present invention will be described with reference to FIG.
7 will be described with reference to FIG. In the present embodiment, two guide pins 16 are provided for one seal ring 2 in the first and second embodiments described above, but one guide pin 16 is provided. Guide pin 1
Except for the point that the shape of FIG. 6 is changed, the remaining configuration and the like are the same as those of the first and second embodiments of the same embodiment. Omitted.

That is, in the present embodiment, the guide pin 16 is located at substantially the center of the seal ring 2 in the circumferential direction.
The guide pins 16 are not provided in a round bar shape but in a rectangular cross section.

By making the cross section rectangular as described above, the seal ring 2 rotates around the guide pin 16 even when a force is applied in either the axial direction or the circumferential direction despite so-called single point support. There is no danger that the seal ring 2 is reliably supported and the stability of the sealing function can be maintained.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
It will be described based on. In the first to third embodiments, although not shown, the seal ring 2 divided into six in the circumferential direction is all configured in the same shape, but in the present embodiment, The six parts are not combined in the same shape but are partially combined in the circumferential direction.

That is, the seal ring 2 divided into six parts is not divided into three parts in each of the upward and downward directions based on the horizontal division position of the vehicle compartment.
The split pieces are arranged so that the abutment portion 13 of the seal ring 2 comes to a vertical plane passing through the axis, and the remaining two split pieces are basically arranged at the horizontal division position of the passenger compartment, and The left and right divided pieces arranged at the same horizontal division position are further divided into two equal parts to surround the rotor 1 with four large divided pieces, four small divided pieces, and conveniently eight divided pieces. I have.

With respect to the four small divided pieces installed at the horizontal section position, a leaf spring is interposed so as to escape radially outward only when the seal fin 5 of the seal ring 2 comes into contact with the rotor 1. The conventional seal ring 02 is employed, and the remaining seal rings 2 employ the seal rings 2 described in the first to third embodiments.

In the horizontal part of the steam turbine casing, the clearance between the rotor 1 and the seal ring 2 changes due to a change due to thermal expansion, a deflection of the rotor 1 due to the weight of the rotor, a change in the axis of the rotor 1 due to a change in the number of revolutions, and the like. Since it is small, the inner diameter of the seal ring 2 is set small from the time of manufacture, and the rotor 1
The structure is such that it returns only when the seal fins 5 of the seal ring 2 come into contact with the seal ring 2. On the other hand, the upper part, which changes greatly as the distance from the horizontal part increases, adopts the first to third embodiments described above, Of the rotor 1 and the seal fins 5 of the seal ring 2
With a structure in which the clearance can be widened and the system can be operated, it is possible to obtain a product with improved reliability while reducing costs in production and assembly.

Although the present invention has been described with reference to the illustrated embodiment, the present invention is not limited to such an embodiment.
It goes without saying that various changes may be made to the specific structure within the scope of the present invention.

[0040]

As described above, according to the present invention, there is provided a seal ring in which seal fins extending toward the outer diameter of the rotor are implanted, and a seal ring receiver for holding the seal ring. A guide pin for connecting the seal ring and the seal ring to guide the radial movement of the seal ring; a spring member disposed around the guide pin to bias the seal ring radially outward; According to the present invention, the seal ring receiver and the seal ring are connected according to the present invention, since the seal device in the steam turbine or the like is formed by providing the pressure acting surface formed radially outward and communicating with the high pressure side of the steam turbine or the like. The seal ring is urged radially outward by a spring member disposed around and surrounding the guide pin to be urged, while the spring is opposed to the urging force of the spring member. At the time of startup and stop when there is no pressure acting on the pressure acting surface due to the balance with the pressure acting on the pressure acting surface communicating with the high pressure side of the steam turbine etc. on the radially outer side of the ring, the seal ring is biased by the spring member. Is pushed outward in the radial direction to secure and maintain the clearance.At rated time when pressure is generated in the steam turbine, it is pushed inward in the radial direction by the steam pressure acting on the pressure action surface to maintain the minimum clearance. Thus, the stability of the sealing function in the clearance portion can be maintained, and the turbine performance can be improved.

According to the second aspect of the present invention, the spring member is formed of a disc spring or a coil spring to constitute an automatic adjustment seal in a steam turbine or the like. The disc springs or coil springs disposed around the guide pins have the same spring constant around the guide pins and provide an even urging force not only in the turbine circumferential direction but also in the axial direction.
Even if a circumferential or axial force acts on the seal ring, the sealing function can be appropriately maintained, and the stability can be further improved.

According to the third aspect of the present invention, the seal ring is divided into a plurality in the circumferential direction, and each of the divided pieces is at least two round shaft guide pins or a single rectangular shaft guide pin. According to the present invention, in the case of a round shaft-shaped guide pin, the shaft is formed by two-point support by two guide pins. A stable sealing function is obtained under stable positioning without any movement in the direction, and in the case of a rectangular shaft guide pin, the rectangular shape is used to support one point despite the use of a rectangular surface. With this simple structure, stable support was achieved, reliable sealing was achieved, and stability of the sealing function could be ensured.

According to the fourth aspect of the present invention,
The seal ring is divided into a plurality of parts in a circumferential direction, and a seal ring corresponding to a horizontal portion is provided in place of the guide pin with a leaf spring interposed between the seal ring and the seal ring receiver and held by the seal ring receiver to be used in a steam turbine or the like. According to the present invention, since the sealing device is configured, according to the present invention, the seal ring supporting portion of the horizontal portion incorporating the leaf spring and the one disposed on the other portion such as the upper and lower portions using the guide pins are selectively used. In this way, the variety of design and production can be expanded, and the cost can be reduced.

[Brief description of the drawings]

FIGS. 1A and 1B show a seal device for a steam turbine according to a first embodiment of the present invention, in which FIG. 1A is an axial sectional view at the time of rated turbine speed, and FIG. FIG.

FIG. 2 is a side view as viewed in the direction of arrows AA in FIG.

FIG. 3 is a plan view as viewed in the direction of arrows BB in FIG. 2;

FIG. 4 is a side view corresponding to FIG. 2, showing a seal device for a steam turbine according to a second embodiment of the present invention.

FIG. 5 is a plan view as viewed in the direction of arrows BB in FIG. 4;

FIG. 6 is a side view corresponding to FIGS. 2 and 4, showing a sealing device for a steam turbine according to a third embodiment of the present invention.

FIG. 7 is a plan view as viewed in the direction of arrows BB in FIG. 6;

FIG. 8 is an explanatory diagram showing a circumferential arrangement of a seal device for a steam turbine according to a fourth embodiment of the present invention.

FIG. 9 is an explanatory view showing a sealing device at an end of a vehicle compartment in a conventional steam turbine.

FIG. 10 is an explanatory diagram showing a main part of FIG. 9 in detail.

FIG. 11 is an explanatory diagram showing a main part of FIG. 10 in detail.

[Explanation of symbols]

 01 rotor 02 seal ring 03 cabin end 04 seal ring reference plane 05 seal fin 06 leaf spring 07 seal ring receiver 1 rotor 2 seal ring 4 seal ring reference plane 5 seal fin 7 seal ring receiver 8a disc spring 8b coil spring 8c dish Spring 9 Guide plate 10 Steam pressure acting surface 11 Thrust receiving surface 12 Seal ring receding surface 13 Abutment portion 14 Bypass hole 15 Spherical seat 16 Guide pin 17 Holding plate 18 Positioning pin

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Eiichiro Watanabe 2-1-1, Aramachi-cho, Niihama, Takasago City, Hyogo Prefecture Inside the Takasago Works, Mitsubishi Heavy Industries, Ltd. No. 1 Inside the Mitsubishi Heavy Industries, Ltd. Takasago Plant (72) Inventor Toshihiro Miyawaki 2-1-1, Araimachi, Takasago-shi, Hyogo Prefecture Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. No. 1-1 Inside Takasago Machinery Works, Mitsubishi Heavy Industries, Ltd.

Claims (4)

[Claims] A seal ring having a seal fin extending toward an outer diameter of the rotor; and a seal ring receiver for holding the seal ring. The seal ring receiver and the seal ring are connected to each other to form a seal ring. A guide pin for guiding the movement in the radial direction, a spring member disposed to surround the guide pin and for urging the seal ring radially outward, a steam turbine formed radially outward of the seal ring, and the like. A sealing device for a steam turbine or the like, characterized in that a pressure action surface communicating with a high pressure side of the steam turbine is provided. 2. The seal device according to claim 1, wherein the spring member is formed of a disc spring or a coil spring. 3. The seal ring is divided into a plurality in the circumferential direction, and each divided piece is connected to the seal ring receiver by at least two round shaft guide pins or a single rectangular shaft guide pin. The sealing device for a steam turbine or the like according to claim 1. 4. The seal ring is divided into a plurality of parts in a circumferential direction, and a seal ring corresponding to a horizontal portion is held by a seal ring receiver with a leaf spring interposed between the seal ring and the seal ring receiver instead of the guide pin. The sealing device for a steam turbine or the like according to claim 1, wherein: