JP4113208B2 - Gas turbine seal structure - Google Patents

Description

The present invention relates to a seal structure of a gas turbine, and more particularly to a seal structure that closes a gap between adjacent shrouds that are divided in a circumferential direction.

The outer periphery of the turbine rotor of the gas turbine is covered with a shroud supported by the housing. The shroud is divided into a plurality of shroud pieces in the circumferential direction in order to improve assemblability and absorb expansion and contraction due to heat. Since a gap is generated between the two adjacent shroud pieces, a seal plate is disposed between the two shroud pieces in order to close the gap. By the way, each shroud piece shrinks more in the circumferential direction than the housing when the turbine is in a cold state, such as when the turbine is stopped. is there. For this reason, conventionally, for example, a seal hole is formed on the upper surface of the seal plate, a stopper member is inserted into the housing from the outside of the housing, and the tip of the seal plate is locked in the lock hole. A method is employed to prevent the plate from falling off.

However, as described above, when the seal plate is held by the stopper member, it is necessary to open holes in the housing and various parts provided between the housing and the seal plate, and productivity and assembly of the seal plate are required. Workability is low.
In addition to this, there is also known a structure that eliminates a gap between the shroud pieces by pressing the shroud pieces radially inward with a spring force (Patent Document 1), but the addition mechanism of the spring force is also complicated. Therefore, productivity and assembly are inferior.
JP 9-228804 A

Therefore, an object of the present invention is to provide a gas turbine seal structure that can reliably prevent the seal plate from dropping while improving productivity and assembly workability.

In order to achieve the above object, a seal structure for a gas turbine according to the present invention includes a turbine rotor and a shroud supported by a housing and covering an outer periphery of the turbine rotor, and the shroud is divided into a plurality in a circumferential direction. A seal plate that closes the gap between the two shroud pieces is disposed between two adjacent shroud pieces, and prevents the gap from expanding across the opposite ends of the two shroud pieces. A restraining member is attached , an insertion groove is provided on the outer peripheral surface of the shroud pieces in the vicinity of the opposing end faces, and the restraining member having a U-shaped cross section is fitted into the insertion groove.

  Since a constraining member is provided between two adjacent shroud pieces adjacent to each other, even if the shroud piece is shrunk in the circumferential direction during cooling, both shroud pieces are separated by the constraining member. Expansion of the gap between them is prevented. For this reason, the seal plate provided in the gap does not fall off. Moreover, since it is a simple structure which only attaches a restraint member between both shroud pieces, it is excellent in productivity and assembly workability | operativity is good.

Furthermore, according to this structure, the clearance gap between both said shroud pieces can be restrained by a simple U-shaped restraining member.

  Further, in a preferred aspect of the present invention, the upper surface of both end portions in the axial direction of the restraining member is brought close to the restraining portion of the housing to restrict the movement of the restraining member in the radially outward direction. According to this configuration, the restricting portion restricts the movement of the restraining member in the radially outward direction, prevents the restraining member from being separated from the shroud pieces, and reliably restrains the gap between the shroud pieces. Yes.

  Furthermore, in a preferred aspect of the present invention, the seal plate has a flat plate shape, and is inserted into insertion grooves formed on the opposing end surfaces of the shroud pieces. According to this configuration, the gap between the shroud pieces can be closed with a simple flat seal plate, but the seal plate easily falls off due to the enlargement of the gap between the shroud pieces. This drop-off can be effectively prevented by the restraining member.

  According to the seal structure of the present invention, it is possible to reliably prevent the seal plate from dropping while improving productivity and assembling workability by a simple configuration in which a restraining member is simply attached between adjacent shroud pieces.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The gas turbine of the present invention includes a compressor that compresses air, a combustor that supplies fuel to the compressed air from the compressor and burns it, and a turbine that is driven by high-temperature and high-pressure combustion gas from the combustor. Yes. FIG. 1 is a longitudinal sectional view showing a main part of a gas turbine. A first stage turbine rotor T is disposed downstream of the first stage blade 3, and a second stage blade 4 is disposed downstream thereof. The turbine rotor T has a rotor blade 1 mounted on the outer periphery of a rotor disk 1. The outer periphery of the turbine rotor T is covered with a shroud 6 supported by the housing 5. The high-temperature and high-pressure combustion gas G from the combustion chamber of the gas turbine is supplied to the combustion gas passage 10 in which the rotor blades 2 and the blades 3 are arranged, and the turbine rotor T is rotated by this combustion gas G to obtain power. .

  FIG. 2 is a sectional view taken along line II-II in FIG. As shown in this figure, the shroud 6 is composed of a plurality of shroud pieces 61 divided in the circumferential direction, and a seal that closes a gap 60 formed between the circumferential end portions between the adjacent shroud pieces 61 and 61. A plate 7 is arranged. In addition, a constraining member 8 that restrains the gap 60 to a certain size or less and prevents the gap 60 from expanding is attached across both ends of the shroud pieces 61 and 61.

The seal plate 7 has a flat plate shape. Insertion grooves 63 are formed in the end faces 61a, 61a of the shroud pieces 61, 61 facing each other in the circumferential direction, and both end portions in the circumferential direction of the seal plate 7 are inserted into the insertion grooves 63 so that the seal plate 7 Is attached. The insertion groove 63 is closed at both ends in the axial direction, whereby the axial position of the seal plate 7 is restricted. The seal plate 7 closes the gap 60 between the shroud pieces 61 and 61, and prevents the combustion gas G passing through the combustion gas passage 10 from leaking outward in the radial direction.

On the other hand, as shown in FIG. 3, the restraining member 8 has a U-shaped cross section having leg portions 81 on both sides in the circumferential direction of the plate-shaped body portion 80, and is manufactured by, for example, press forming of a metal plate material. On the other hand, as shown in FIG. 2, fitting grooves 64 are provided on the outer peripheral surfaces of the shroud pieces 61, 61 in the vicinity of the end faces 61 a, 61 a facing each other in the circumferential direction. It is fitted in and attached.

Further, the restraining member 8 is restricted from moving radially outward by the housing 5 shown in FIG. 1 as follows. Segment supports 51 and 51 are attached to the housing 5 at both ends in the axial direction of the shroud piece 61, and engaging grooves are supported by engaging both end portions in the axial direction of the shroud piece 61 with the segment support 51. 52 is formed. By inserting both axial end portions of the restraining member 8 into the engaging grooves 52, 52, the upper surface thereof is brought close to the upper surface 52a of the engaging groove 52, thereby causing the restraining member 8 to radially outward. Restricts movement. Therefore, the engaging groove 52 functions as a restricting portion of the restraining member 8.

In the above configuration, the shroud 6 becomes hot due to contact with the high-temperature combustion gas G during operation of the gas turbine, but the housing 5 is not so hot. Therefore, when the gas turbine is in a cold state after the gas turbine is stopped, the shroud 6, which has a temperature lower than that of the housing 5, contracts more than the housing 5. As a result, the gap 60 between the shroud pieces 61 and 61 shown in FIG. Here, since the restraining member 8 is provided straddling the two adjacent shroud pieces 61, 61, even if the shroud pieces 61, 61 are greatly contracted in the circumferential direction during the cold state, the restraining member 8 is provided. Thus, the gap 60 between the shroud pieces 61 and 61 is limited to a certain size or less, that is, to a size determined by the distance between the both leg portions 81 and 81 of the restraining member 8, and the gap 60 is enlarged to a certain level or more. Is blocked. For this reason, it is possible to prevent the seal plate 7 provided in the gap 60 from falling off. Moreover, since it is the simple structure which only attaches the restraint member 8 which consists of a board | plate material of a simple shape between both shroud pieces 61 and 61, it is excellent in productivity and assembly workability | operativity is also good.

Further, as shown in FIG. 1, the upper surface of both end portions in the axial direction of the restraining member 8 is brought close to the restraining portion (engagement groove) 52 of the housing 5 to restrain the restraining member 8 from moving outward in the radial direction. Accordingly, it is possible to easily prevent the restraining member 8 from falling off the shroud piece 61.

It is sectional drawing along the II line of FIG. 2 which shows the principal part of the gas turbine concerning one Embodiment of this invention. It is sectional drawing along the II-II line of FIG. It is a disassembled perspective view which shows the principal part of the embodiment.

Explanation of symbols

T Turbine rotor 5 Housing 52 Restriction part (engagement groove)
6 shroud 60 clearance 61 shroud piece 63 insertion groove 64 insertion groove 7 seal plate 8 restraint member

Claims (3)

A turbine rotor, and a shroud supported by a housing and covering an outer periphery of the turbine rotor;
The shroud comprises a plurality of shroud pieces divided in the circumferential direction,
Between two adjacent shroud pieces, a seal plate that closes the gap between the two shroud pieces is disposed,
A restraining member that prevents expansion of the gap across the opposite ends of both shroud pieces is attached ,
A gas turbine seal structure in which an insertion groove is provided on an outer peripheral surface of the shroud pieces in the vicinity of opposing end surfaces, and the restraining member having a U-shaped cross section is inserted into the insertion groove . 2. The gas turbine seal structure according to claim 1 , wherein the upper surface of both axial end portions of the restraining member is close to the restricting portion of the housing, and movement outward in the radial direction is restricted. 3. The gas turbine seal structure according to claim 1 , wherein the seal plate has a flat plate shape and is inserted into insertion grooves formed in opposite end surfaces of the shroud pieces.

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