JP2938856B1 - Gas turbine seal mechanism - Google Patents

Abstract

An object of the present invention is to provide a sealing mechanism for an output turbine shaft of a gas turbine, the sealing effect being improved by a simple configuration. SOLUTION: An annular seal member 13 is disposed in a casing 7 of a gas turbine 1 at a portion where the output turbine shaft 3a penetrates, with a slight gap being provided around an outer periphery of the output turbine shaft. It comprises an annular space 14 formed on the inner peripheral side, and a pressure relief pipe 15 for discharging combustion gas from the annular space 14 to the exhaust portion 7c on the downstream side of the output turbine 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gas turbine and a sealing mechanism for the gas turbine. More specifically, a seal mechanism for preventing a combustion gas from leaking to an output take-out side from a penetration portion of an output turbine shaft in a gas turbine,
The present invention also relates to a gas turbine to which the seal mechanism is applied, wherein the direction of the rotation axis of the gas generator and the direction of the rotation axis of the output turbine intersect (including orthogonal).

[0002]

2. Description of the Related Art As a conventional gas turbine, as shown in FIG. 5, a rotating shaft 52a of a gas generator 52 for generating high-temperature and high-pressure combustion gas and an output turbine for extracting the energy of the combustion gas as rotational force. 53 rotation shaft 53a
Are arranged coaxially with each other (hereinafter also referred to as horizontal type)
Is common.

The gas generator 52 in the horizontal gas turbine 51 includes a compressor 54 for compressing air, a combustor 55 for injecting fuel into the compressed air for combustion, and rotating the compressor 54. It comprises a compressor drive turbine 56 for driving. And the gas generator 5
The combustion gas injected downstream from the gas turbine 2 acts on the output turbine 53 without being changed in direction, and thereafter, the casing 57
The direction is changed in the scroll flow path portion 57a to reach the discharge portion 57b. In addition, "upstream" used in this specification
The term “downstream” means upstream and downstream based on the flow direction of the combustion gas, “front” means upstream, and “rear”
The term means downstream.

A rotating shaft 53a of the output turbine 53 is provided at the rear thereof with a casing 57 and a bearing base 59a to be described later.
And is connected to driven equipment such as a pump and a generator (not shown). Sealing members 58 are disposed at the casing 57 through which the rotating shaft 53a penetrates and at a bearing base 59a, which will be described later, to minimize leakage of combustion gas from around the rotating shaft 53a. Seal member 58
The rotary shaft 5 is provided outside the through portion of the casing 57 in which the
A bearing member 59 for supporting 3a is provided. The bearing receiving portion of the casing 57 is
Call. The seal member 58 has a large number of labyrinth grooves 58a formed on the inner peripheral side of the penetrating portion so as to correspond to the outer periphery of the rotating shaft 53a. The leakage of the combustion gas is suppressed by the pressure drop by the labyrinth groove 58a.

[0005] In the drawing, reference numeral 60 denotes a cascade vent for smoothly turning the airflow from above in the horizontal direction.

On the other hand, when the driven equipment is a vertical shaft pump or the like, the axial direction of the gas generator and the driven equipment may intersect at a right angle or another angle. FIG. 6 shows such a conventional gas turbine 61. In the present gas turbine 61, a rotation shaft 62a of a gas generator 62 and a rotation shaft 63a of an output turbine 63 are orthogonal to each other (hereinafter, L).
The combustion gas is substantially 90 ° directed between the gas generator 62 and the output turbine 63 in the direction of the output turbine 63 by the scroll flow path 64 a of the casing 64.
The flow path is changed, and passes through the output turbine 63 to reach the discharge section 64b. Since the output direction of the output turbine 63 is necessarily on the opposite side of the combustion gas discharge portion 64b, the rotating shaft 63a of the output turbine 63 is connected to the casing 64 between the gas generator 62 and the output turbine 63.
Penetrates. Similarly to the horizontal gas turbine 51 (FIG. 5), the rotating shaft 63a of the output turbine 63 is rotatably supported by a bearing 66 in a bearing base 66a provided outside the penetrating portion. A seal member 65 is provided at the penetrating portion of the casing and the penetrating portion of the bearing base 66a. The sealing member 65 also has a labyrinth groove 65a.
have.

As an example of such a conventional L-type gas turbine, one disclosed in Japanese Patent Application Laid-Open No. Hei 9-189240 is known.

[0008]

In the horizontal gas turbine 51 (FIG. 5), a portion where the rotating shaft 53a of the output turbine 53 penetrates the casing 57 is disposed downstream of the output turbine 53. The gas temperature has dropped to, for example, about 400 to 500 ° C., and the pressure has a value close to the atmospheric pressure. Therefore, the leakage of the combustion gas from the seal member 58 at the penetration portion to the outside is extremely small and does not pose a problem.

However, in the L-type gas turbine 61 (FIG. 6), the gas generator 62
And the power turbine 63, the temperature of the combustion gas there exceeds 600 ° C., the pressure is higher than the atmospheric pressure (for example, 2-3 kg / cm ² g), and the sealing member 65 Inside and outside the casing 64 sandwiching
A large pressure difference is generated between the inside of the casing 64 and the inside of the bearing base 66a. Therefore, the combustion gas leaks from the inside of the casing 64 and heats the bearing 66 and the peripheral devices in the bearing base 66a. Further, the pressure inside the bearing base 66 is increased, and various troubles such as leakage of the lubricating oil along with the gas from the seal member 65 on the driven device side of the bearing base 66a may occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and is intended for external equipment by processing combustion gas that has reached a casing through portion of a rotating shaft of an output turbine without leaking to the outside. It is an object of the present invention to provide a seal mechanism that can prevent adverse effects.

[0011]

According to the present invention, there is provided a seal mechanism comprising:
A gas generator for generating a high-temperature and high-pressure gas, and an output turbine for extracting gas energy as rotational force, the rotational axis of which is arranged in a direction intersecting the rotational axis of the gas generator. A sealing mechanism for a through portion of a rotation shaft of an output turbine in a gas turbine having the same, wherein an annular seal member is provided around the rotation shaft of the output turbine in the through portion, and a combustion member is provided in the seal portion. and a pressure relief means for discharging the gas, on
The output turbine side is
A bearing base that rotatably supports the turning shaft is arranged,
The penetrating portion projects from the output turbine side wall of the bearing stand.
Formed on the force take-out side wall,
The pressure relief means is provided.
Is characterized in that both seal portions communicate with each other.

Therefore, since the combustion gas that has reached the seal portion can be released, the leakage of the combustion gas from the penetration portion to the outside can be effectively prevented.
Further, the output turbine is provided on the output extraction side of the output turbine.
-A bearing base for rotatably supporting the rotation axis of the
The above-mentioned penetrating part to the bearing base
Formed on the output turbine side wall and the output take-out side wall
Then, the seal portion is provided in each of the penetration portions, and the pressure
Force relief means are also configured to communicate both seals.
So that the above-mentioned sealing effect can be achieved.
The pressure in both seals of the bearing base is approximately the same
As a result, there is no gas flow passing through the bearing
Sealing effect on the seals,
Leakage can also be prevented.

[0013] Then, the seal member is brought close to the outer periphery of the output turbine shaft with a slight gap therebetween to form an annular space between the inner periphery of the seal member and the outer periphery of the output turbine shaft.
By configuring the pressure relief means as a pressure relief passage communicating from the annular space to the low-pressure portion, the above-described effects can be achieved while preventing damage to the seal portion and the output turbine shaft. Further, since such an operation and effect can be achieved with a simple configuration, the service life of the seal portion can be prolonged, and the maintainability is also improved.

The low-pressure section is, for example, a downstream side of an output turbine described later, and an exhaust gas processing section separately provided outside a casing of the gas turbine.

The pressure relief passage communicates from the annular space to the outlet of the cascade of the output turbine from the annular space. Since the function of sucking the gas can be used, the leakage of the combustion gas from the through portion to the outside can be more effectively prevented.

[0016]

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sealing mechanism according to the present invention will be described based on an embodiment shown in the accompanying drawings.

[0018] FIG. 1 is a sectional view showing an example of a gas turbine shea Lumpur Organization applied. FIG. 2 is a sectional view showing a portion of a sealing mechanism in the gas turbine of FIG. FIG.
FIG. 4 is a cross-sectional view showing another example of the gas turbine to which the seal mechanism of FIG. 2 is applied. Figure 4 is a sectional view showing an example of a gas turbine implementation form is applied in the sealing mechanism of the present invention.

FIG. 1 shows an L-type gas turbine 1, which includes a rotating shaft 2a of a gas generator 2 and a rotating shaft of an output turbine 3 for taking out the energy of the combustion gas as a rotating force (hereinafter referred to as an output turbine shaft). 3a) are arranged in a direction perpendicular to the direction.

The gas generator 2 includes a compressor 4 for compressing the sucked air, a combustor 5 for injecting fuel into the compressed air and burning it, and a rotary drive for the compressor 4. It comprises a compressor drive turbine 6.

The gas generator 2 and the output turbine 3 are housed in a casing 7. The air sucked through the intake portion 7a of the casing is compressed by the compressor 4 and then mixed with the fuel in the combustor 5 and burned to produce combustion gas. It is injected backward from 2. Next, the direction is changed by approximately 90 ° by the scroll flow path portion 7b of the casing 7 to reach the output turbine 3, and after the output turbine 3 is rotated, it reaches the exhaust portion 7c of the casing 7.

A plurality of discs 9 on which turbine blades 8 are radially arranged are arranged on the output turbine shaft 3a. From the inner peripheral surface of the casing 7, stationary blades 10 alternately arranged with the discs 9 are arranged. Is protruding.

The output turbine shaft 3a extends on the side opposite to the exhaust portion 7c, and penetrates through the casing 7 and is rotatably supported by a bearing 11 outside the casing 7. The bearing 11 is accommodated in a bearing stand 11 a attached to the casing 7. The output turbine shaft 3a is connected to driven equipment such as a pump and a generator (not shown) through a wall 11b of a bearing base 11a behind the bearing 11.

The pressure of the combustion gas in the exhaust part 7c is close to the atmospheric pressure, and the pressure inside the bearing stand 11a is also substantially the atmospheric pressure.

A seal mechanism 12 is provided at a portion of the casing 7 penetrating the output turbine shaft 3a. The seal mechanism 12 includes an annular seal member 13 disposed close to and around the output turbine shaft 3a. On the inner peripheral surface of the seal member 13 corresponding to the outer periphery of the output turbine shaft 3a, a large number of labyrinth grooves 14a are formed in the circumferential direction, and an annular space 14 is formed at an intermediate portion thereof. Therefore, the combustion gas enters the annular groove 14 while dropping the pressure while passing through the labyrinth groove 14a. The annular space 14 may be a single groove formed in the circumferential direction, or may be a plurality of mutually independent grooves.

On the other hand, from the seal member 13 to the outlet of the output turbine cascade of the exhaust portion 7c, a pressure relief pipe 15 as a pressure relief means is provided, whereby the inside of the annular space 14 and the outlet of the output turbine cascade are connected. Is communicated. The output turbine cascade outlet is a portion where the combustion gas flows at a high speed in the exhaust portion 7c, and the static pressure in this portion is usually a negative pressure. The number of the pressure relief pipes 15 may be one or two or more. The number may be set according to the size of the annular space 14 and the inner diameter of the pressure relief pipe 15.

With this configuration, the combustion gas that has entered the annular space 14 does not leak in the direction of the bearing base 11a, but is discharged by the pressure relief pipe 15 to the low-pressure portion.
Flow to c. In this manner, even in a conventional L-type gas turbine, even if higher-pressure combustion gas enters the annular space 14, leakage of the combustion gas in the direction of the bearing pedestal 11a is prevented.

As described above, the sealing effect is improved by the very simple structure of the groove and the pipe, so that the manufacturing cost can be reduced and the life of the sealing mechanism can be extended.

The pressure relief means is not particularly limited to the above-mentioned piping, but may be a manifold-shaped cavity formed in a wall of the casing 7 of the gas turbine 1 or the like. In short, any passage may be used as long as the combustion gas that has entered the annular space 14 can escape.

A second annular seal member 18 is also provided at a penetrating portion of the wall 11b of the bearing base 11a through which the output turbine shaft 3a penetrates. The seal member 18 has only a labyrinth groove formed therein.
4 and the pressure relief pipe 15 are not provided.

FIG. 2 is an enlarged view of a portion A in FIG. 1 showing the sealing member 13 in more detail. In the figure, a front portion (closer to the bearing 11) of the first stage disk 9 in the output turbine shaft 3a is a portion of the output turbine shaft 3a where the casing 7 penetrates. An annular groove member 16 is fixedly provided on the outer periphery of the through portion of the output turbine shaft 3a. A sealing member 13 is fixedly provided on the inner periphery of the through portion of the casing 7 so as to correspond to the groove member 16. The annular groove 14 in the circumferential direction is formed on the inner periphery of the seal member 13. A groove 16 a is also formed on the outer periphery of the groove member 16, and an annular space 17 is formed by the groove 16 a and the annular groove 14 of the seal member 13. Although only the annular groove 14 is shown in FIG. 1,
The annular space 17 may be constituted only by the annular groove 14 as shown in FIG.
It may be composed only of the above.

Narrow gaps Sa and Sb are formed on both sides of the annular space 17, and the labyrinth grooves 1
4a are formed.

One end of the pressure relief pipe 15 is connected to the annular space 17. Although the middle part of the pressure relief pipe 15 is not shown, it is connected to the outlet of the output turbine cascade through the outside of the scroll flow path part 7b of the casing 7, as shown in FIG. Pressure relief pipe 15
, Ie, the passage area of the combustion gas, is larger than the area of the gap Sb of the annular space 17 on the bearing stand 11a side.

The other end of the pressure relief pipe 15 is shown in FIG.
As shown in (1), since the combustion gas is inserted into the outlet of the output turbine cascade in which the combustion gas flows at a high speed, the suction effect (ejector effect) by the high-speed combustion gas flow acts.

The sealing member 13 in the casing 7
A bearing 11 of the output turbine shaft 3a is provided at a front portion.

In the L-type gas turbine 21 shown in FIG. 3, the bearing 23 of the output turbine shaft 22a is
It is arranged downstream of 2. The bearing stand 23 is supported by a plurality of struts 24 formed inside the casing 7. At the portion where the output turbine shaft 22a penetrates the casing 25, the same sealing mechanism 12 as in the gas turbine 1 described above, that is, the annular sealing member 13 in which the annular groove 14 is formed and the pressure relief pipe 1
5 are provided. Therefore, the description of the sealing mechanism in this portion is omitted. In addition, the structure of the other parts is the same as that of the above-described gas turbine 1 (FIG. 1), and thus the description is omitted.

An annular seal member 18 which is close to the periphery of the output turbine shaft 22a is provided in a portion of the bearing base 23 through which the output turbine shaft 22a penetrates. An annular space 27 is also formed on the inner peripheral surface of the seal member 18. At the position where the seal member 18 is provided on the bearing stand 23, the temperature of the combustion gas is reduced and the pressure is close to the atmospheric pressure, similarly to the position where the seal member 58 is provided in the conventional horizontal gas turbine 51 (FIG. 5). Therefore, the above-described pressure relief pipe 15 is not provided.

Of course, a pressure relief pipe 15 may be provided. In that case, it is preferable to use the ejector effect by inserting the other end of the pressure relief pipe into the high flow rate part of the exhaust part 25c of the casing 25 in a posture facing downstream as described above.

The L-type gas turbine 31 shown in FIG. 4 also has an annular space 14 similar to the gas turbine 1 (FIG. 1) at the portion of the casing 32 where the output turbine shaft 3a passes.
Is provided. The gas turbine 31 further includes a rear wall 33b of a bearing base 33a.
The seal member 3 in which the annular space 34 similar to the seal member 13 is formed also in the penetrating portion of the output turbine shaft 3a
5 are provided. Then, the two annular spaces 14, 3
The pressure relief pipe 36 is connected to the exhaust port 32c of the exhaust unit 32c and communicates with the outlet of the output turbine cascade.
The other configuration is the same as that of the gas turbine 1 of FIG. 1, and the description is omitted, and the same members are denoted by the same reference numerals.

By doing so, the sealing effect between the inside of the casing 32 and the inside of the bearing stand 33a can be obtained, and the sealing effect between the inside of the bearing stand 33a and the outside on the driven device side can be improved. Further, since the pressures at both penetrating portions of the bearing base 33a are substantially the same, the bearing base 33a
Since there is no gas flow passing through the inside a, leakage of lubricating oil and the like can be prevented.

In the above embodiment, the other ends of the pressure relief pipes 15, 36 connected to the annular spaces 14, 34 are inserted into the exhaust portions 7c, 25c, 32c of the casings 7, 25, 32. However, the configuration is not particularly limited. For example, an exhaust processing unit (not shown) composed of a tank having an atmospheric pressure or an internal pressure close to the atmospheric pressure or the like is provided outside the casings 7, 25, and 32. The ends may be connected to exhaust the combustion gas in the annular space.

[0042]

According to the seal mechanism of the present invention, the combustion gas that has reached the seal portion can be released to a predetermined place, so that the leakage of the combustion gas from the through portion to the outside can be effectively prevented. And the deterioration of the seal portion can be suppressed. If the combustion gas is released to the high-speed flow section immediately downstream of the output turbine, the suction effect can be used, and the sealing effect is further improved.

[Brief description of the drawings]

1 is a sectional view showing an example of a gas turbine sheet Lumpur Organization is applied.

FIG. 2 is a sectional view showing a portion of a sealing mechanism in the gas turbine of FIG.

FIG. 3 is a cross-sectional view showing another example of the gas turbine to which the seal mechanism of FIG. 2 is applied.

Implementation form of sealing mechanism of the present invention; FIG is a sectional view showing an example of the applied gas turbine.

FIG. 5 is a sectional view showing an example of a gas turbine to which a conventional sealing mechanism is applied.

FIG. 6 is a cross-sectional view showing another example of a gas turbine to which a conventional sealing mechanism is applied.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-189240 (JP, A) JP-A-9-256815 (JP, A) Japanese Utility Model Shou 59-150996 (JP, U) (58) Field (Int.Cl. ⁶ , DB name) F02C 7/28 F01D 11/00 F02C 3/10

Claims (3)

(57) [Claims] 1. A gas generator for generating a high-temperature and high-pressure gas, and a rotary shaft arranged in a direction intersecting with a rotary shaft of the gas generator, for extracting gas energy as rotary force. A sealing mechanism for a through portion of a rotation shaft of the output turbine in the gas turbine having the output turbine of the above, wherein an annular seal member disposed around the rotation shaft of the output turbine in the through portion; Pressure relief means for discharging the disposed combustion gas is provided, and the output turbine of the output turbine is
A bearing base that rotatably supports the rotating shaft is provided.
And the penetrating portion is a side wall of the power turbine in the bearing stand.
And the output take-out side wall,
Each of these seals is provided, and the pressure relief
A sealing mechanism for a gas turbine, wherein the means communicates the two sealing portions . 2. The seal member is close to the outer periphery of the output turbine shaft with a slight gap therebetween, and an annular space is formed between the inner periphery of the seal member and the outer periphery of the output turbine shaft. 2. The gas turbine sealing mechanism according to claim 1, wherein the pressure relief means comprises a pressure relief passage communicating from the annular space to the low pressure portion. 3. The gas turbine sealing mechanism according to claim 2, wherein said pressure relief passage communicates from said annular space to an outlet of a cascade of a power turbine.