JPH05156968A - Shaft seal of gas turbine - Google Patents

Abstract

PURPOSE:To keep off any wear in a seal surface as maintaining good sealability by installing a stopper which has a side face being opposed to a part uncontacted with a sealing side of a seal holder among the seal sides of a seal ring, with the specified clearance. CONSTITUTION:A turning shaft 1 is supported on a housing 6 by means of a bearing 9 positioned by a seal holder 3 or the like. In addition, a retainer 7' is installed in an opening of the housing 6 where the seal holder is situated. Further a seal ring 4 is inset in a ring groove 3a of the seal holder 3, while a spring ring 5 is inset in the ring groove 4a of the seal ring 4, thereby making the seal ring 4 contact with the retainer 7'. Then a stopper 10 having a side face 10a being opposed to a part uncontacted with a seal side 3b of the seal holder 3 out of a seal side 4a of the seal ring 4, with the specified clearance, is formed in the retainer 7' as one body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal ring type gas turbine shaft seal structure.

[0002]

2. Description of the Related Art A shaft seal structure for a gas turbine as described above is described in Japanese Utility Model Laid-Open No. 1-11150.
Its structure is shown in FIG. In the figure, 1 is a rotation axis, 2
Is an impeller fixed to the rotating shaft 1. A seal holder 3 having an annular groove 3a on its outer surface is fitted and inserted into the rotary shaft 1. A seal ring 4 provided in the annular groove 3a and having an annular groove 4a on the inner surface is provided in the annular groove 4a.
A spring ring 5 inserted in a is biased outward in the radial direction, and the outer surface of the spring ring 5 is pressed against and brought into contact with the annular inner surface of the retainer 7 fixed to the opening of the housing 6.

As a result, the seal ring 4 is held on the housing 6 side, and the seal ring 4 and the retainer 7 are provided.
There is almost no gap between and, thus providing a good seal during this. Further, since the outer side (impeller side) of the housing 6 normally has a high pressure, the seal ring 4 is urged toward the inner side of the housing 6, so that the right side surface 4b of the seal ring 4 in FIG. 3 is pressed against the right side surface 3b of the annular groove 3a of No. 3 and each acts as a seal side surface, and since there is almost no gap between them, a good seal between the seal ring 4 and the seal holder 3 can be obtained. Done.

[0004]

The above-mentioned gas turbine shaft seal guarantees a good sealing property.
Since the seal side surface of the seal holder rotates and slides with respect to the seal side surface of the seal ring held on the housing side, both are worn. Either one of the seal ring and the seal holder is usually made of a relatively soft material such as carbon in order to improve the sealing property, so that this member loses its function due to the above-mentioned wear. It does not take long to reach, which determines the durability of this shaft seal.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a seal ring type gas turbine shaft seal capable of improving durability.

[0006]

In order to achieve the above object, a shaft seal of a gas turbine according to the present invention is held by a seal holder which rotates together with a rotary shaft on a housing side and is urged by an axial urging force. A seal ring having a seal side surface abutting the seal side surface of the seal holder;
A stopper fixed to the housing side having a side surface facing at least a part of the seal side surface of the seal holder that is not in contact with the seal side surface of the seal holder with a predetermined clearance. It is characterized by

[0007]

The above-described gas turbine shaft seal is similar to the conventional one.
Since the seal side surface of the seal ring is brought into contact with the seal side surface of the seal holder by the axial biasing force, a good sealability is ensured during this period. On the other hand, when the abrasion due to the rotation and sliding of the two advances, a part of the seal side surface of the seal ring contacts the stopper when the total amount reaches the predetermined clearance. No wear occurs due to the absence of rotational sliding between the two members, and at this position the seal ring is held against the axial biasing force. At this point, there is almost no gap between the seal surfaces of the seal ring and the seal holder, the sealability is maintained, wear of both seal surfaces is prevented, and the durability of the shaft seal can be improved. It will be possible.

[0008]

FIG. 1 is an overall sectional view of an embodiment of a shaft seal of a gas turbine according to the present invention. In the figure, as in the prior art shown in FIG. 3, 1 is a rotary shaft, 2 is an impeller,
3 is a seal holder.

The rotary shaft 1 is supported by a housing 6 by a bearing 9 positioned by a seal holder 3 and a collar 8. A retainer 7'having an annular inner surface is provided in the opening of the housing 6 in which the seal holder 3 is located.
Is provided.

The annular groove 3a of the seal holder 3 is provided with a carbon seal ring 4 which is diametrically divided into two and has an annular groove 4a on the inside thereof in order to enable the assembly thereof. A spring ring 5 for urging the seal ring 4 outward in the radial direction is inserted therein, and the outer surface of the seal ring 4 is brought into contact with the annular inner surface of the retainer 7 ′ to perform a seal between the two, and The ring 4 is held by the retainer 7 '.

The outside of the housing 6 in which the impeller 2 is located is normally at a higher pressure than the inside, whereby the seal ring 4 is urged toward the inside of the housing 6 in the axial direction, and the right side surface of the seal ring 4 in FIG. 4b and seal holder 3
Contact the right side surface 3b of the annular groove, and seal side surfaces 3b, 4
work as b.

An enlarged view of the seal ring 4 portion is shown in FIG. In the figure, the retainer 7'has a seal ring 4
The stopper 10 is integrally formed with a side surface 10a of the seal side surface 4b which faces the seal side surface 3b of the seal holder 3 with a predetermined clearance d.

This predetermined clearance d becomes negative (the side surface 10a of the stopper 10 is located on the left side of the seal side surface 3b of the seal holder 3) after the assembly is completed, even in consideration of the processing accuracy and the assembly error of each member. It is preferably determined to the closest value to zero.

In the shaft seal of the gas turbine of this embodiment, as in the conventional case, the seal ring 4 is urged toward the radially outer side and the axial direction inner side of the housing 6 by the high pressure outside the spring ring 5 and the housing 6, and the retainer 7 Good sealability is assured with respect to the annular inner surface of ′ and the seal side surface 3b of the seal holder 3.

Further, as in the conventional case, the seal side surface 4b of the seal ring 4 and the seal side surface 3b of the seal holder 3 are rotationally slid, so that both of them are worn, and accordingly, the seal ring 4 is subjected to the external pressure of the housing 6. It moves to the inside of the axial housing 6. When the movement of the seal ring 4 due to the wear of the both reaches the predetermined clearance d, a part of the seal side surface 4b of the seal ring 4 abuts the side surface 10a of the stopper 10, and during this time there is no rotational sliding, so the wear is reduced. It does not happen and holds the seal ring 4 against the external pressure of the housing 6 in this position.

Even at this time, there is almost no gap between the seal side surface 4b of the seal ring 4 and the seal side surface 3b of the seal holder 3, the sealability is maintained, and both seal side surfaces 3b and 4b are maintained. Sliding between them is prevented, and the durability of the shaft seal of this embodiment can be improved.

By setting the predetermined clearance d to be close to zero, the seal side surface 4b of the seal ring 4 and the seal holder 3 are sealed until the seal side surface 4b of the seal ring 4 contacts the side surface 10a of the stopper 10. Although the amount of wear on the side surface 3b can be reduced, the seal side surface 4b of the seal ring 4 is located on the side surface of the stopper 10 before the amount of wear on either one of the seal side surfaces 3b and 4b reaches a level that impairs its function. Obviously, the size may be such that it abuts 10a.

Further, as shown in FIG. 2, the stopper 10 is tapered toward the inner side in the radial direction so that the tip has an edge shape, so that the gap between the tip and the seal holder 3 is made small. Also, when the rotating shaft 1 is eccentric and both come into contact with each other, the rotation resistance is not so great, and the shape of the stopper 10 functions as a labyrinth seal against the pressure outside the housing 6,
As a result, it is possible to ensure better sealing performance than before.

In this embodiment, the stopper 10 is the retainer 7 '.
It is formed integrally with the housing 6, but as a separate member the housing 6
It is obvious that the durability of the shaft seal can be similarly improved even if the shaft seal is fixed to.

[0020]

As described above, according to the shaft seal of the gas turbine of the present invention, by providing the simple stopper,
Wear of both seal sides of the seal ring and the seal holder due to the use of the gas turbine while maintaining the sealability,
When the predetermined amount is reached, further wear can be prevented, and the durability of the shaft seal can be considerably improved.

[Brief description of drawings]

FIG. 1 is an overall sectional view of a shaft seal of a gas turbine according to the present invention.

FIG. 2 is an enlarged view of part A in FIG.

FIG. 3 is an overall sectional view of a shaft seal of a conventional gas turbine.

[Explanation of symbols]

 1 ... Rotary shaft 3 ... Seal holder 4 ... Seal ring 5 ... Spring ring 7,7 '... Retainer 10 ... Stopper

Claims (1)

[Claims] 1. A seal holder that rotates together with a rotating shaft,
A seal ring, which is held on the housing side and has a seal side surface that abuts on a seal side surface of the seal holder by an axial urging force; A stopper that is fixed to the housing side and has a side surface that faces at least a part of the non-existing portion with a predetermined clearance,
A shaft seal for a gas turbine, comprising: