JPH0680283B2 - Flushing method of steam turbine - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for flushing a steam turbine of a power plant.

[0002]

A labyrinth seal device is generally used as a device for sealing a turbine axle in a steam turbine for driving an alternator for nuclear power generation, thermal power generation and the like. This labyrinth seal device passes through the multiple fixed blades that are pumped into the turbine chamber and fixed to the casing side, and the multiple rotary blades mounted on the turbine axle between the fixed blades one after the other, and Leakage of steam that rotates the rotor blades outside the turbine chamber,
And to prevent the outside air from leaking into the turbine chamber. As shown in FIG. 3, the shaft hole portion of the casing forming the turbine chamber A is fitted to the inner periphery of the housing 1 so that the inner peripheral end portion is The turbine axle 2 has a large number of fin-shaped throttle pieces 4, 4, ... Which are close to each other with a gap 3 left therebetween, and the labyrinth seal device is ventilated with a gland seal steam (not explained). The inside of A and the outside air are cut off.

A plant such as a nuclear power plant is regularly inspected from the viewpoint of maintaining safety. In this regular inspection work, the water piping system and the lubricating oil piping system are flushed, but when flushing the water piping system, it is necessary to create a vacuum in the turbine chamber A in order to remove oxygen in the water. Vent the gland seal vapor through the labyrinth seal device. Since the temperature of the gland seal steam is about 150 ° C., if the gland seal steam is ventilated while the turbine axle 2 is stationary, the turbine axle 2 may be curved, and therefore the turbine axle 2
Needs to be rotated. Further, when the turbine axle 2 is rotated, if foreign matter remains mixed in the lubricating oil supplied to the bearing, the bearing section and the shaft journal section will be damaged by the foreign matter, so the lubricating oil piping system will be flushed first. There is a need to.

[0004]

That is, according to the prior art, first, the lubricating oil piping system is flushed, and after the flushing is completed, it is confirmed that no foreign matter is present in the lubricating oil, and then the labyrinth seal device. The gland seal steam was introduced into the turbine to evacuate the turbine chamber while rotating the turbine axle, and after reaching a predetermined vacuum value, the water piping system was flushed, which lengthened the construction period.

The present invention has been made under the circumstances described above, and its technical problem is to shorten the period for flushing a steam turbine.

[0006]

The above-mentioned technical problems are as follows.
The present invention can effectively solve the problem. That is, the steam turbine flushing method according to the present invention is provided in a housing formed in a shaft hole portion of a casing that defines a turbine chamber, and has a large number of fin-shaped throttle pieces whose inner circumference is close to the outer circumference of the turbine axle. A labyrinth seal device having a rubber-like elastic material which is supported by the housing through an adapter ring which is provided in parallel with the labyrinth seal device and whose outer peripheral portion is divided in the circumferential direction, and which is annularly joined at one position in the circumferential direction. A hollow inflatable seal, and a steam turbine having a turbine axle sealing device consisting of: stopping the turbine axle, pressurizing the inflatable seal to bring it into close contact with the turbine axle, and vacuuming the turbine chamber, This is for flushing the water piping system on the turbine room side.

[0007]

In the above construction, the inflatable seal is expanded by injecting pressurized air or other pressurized fluid into the hollow portion thereof from the external pressure source through the pressurized fluid feed passage to stop the outer periphery of the turbine axle. Since it closely adheres to the surface and functions as a shaft seal, it is possible to maintain the airtightness (vacuum) of the turbine chamber without charging the gland seal steam to the labyrinth seal device. Therefore, it is also necessary to rotate the turbine axle. Absent. Therefore, it is not necessary to perform the flushing of the lubricating oil piping system before the flushing of the water piping system on the turbine chamber side, and the flushing of the water piping system and the lubricating oil piping system can be performed simultaneously or in parallel. Further, since the inflatable seal is wound around the outer periphery of the turbine axle and is annularly coupled at one location in the circumferential direction, and is supported by the housing via the adapter ring divided in the circumferential direction, it is easy to attach and detach. It can be removed except during the flushing period described above.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a shaft seal portion of a low-pressure turbine in a pressurized water nuclear power plant, and reference numeral A denotes a plurality of non-rotating fixed blades (not shown) and a plurality of rotating blades mounted on the turbine axle 12 and rotating between the fixed blades. A turbine chamber for accommodating a rotary blade (not shown) in stages, 11 is a housing attached to a shaft hole portion of a casing forming the turbine chamber A, and 15 is an inner peripheral end fitted to the inner periphery of the housing 11. The slit 13 on the outer circumference of the turbine axle 12
A large number of fin-shaped diaphragm pieces 14, 14 ...
Is a labyrinth seal device, 16 is an adapter ring attached to the outer peripheral surface of the housing 11 by a bolt 17, and 18 is a rubber having a hollow portion 20 fitted in an annular groove 19 on the inner periphery of the adapter ring 16. It is an inflatable seal made of elastic material.

The adapter ring 16 is divided into two in the circumferential direction, and the divided two members are joined by bolts 21 and 22 to form an annular shape, and the inflatable seal 18 is a string-shaped one, and the turbine is Axle 12
It is wrapped around the outer circumference of and is joined at both ends to form a ring. As shown in FIG. 2, one end 23 ′ of the hollow portion 20 of the inflatable seal 18 is joined to an opening 20 ′ opened on the outer diameter side of a part of the hollow portion 20 in the circumferential direction, and the hollow portion 20 is connected to the adapter ring 16. A hollow anchor pin 23 which is inserted in the direction and fixed by a nut 24 is connected to an external pressure source (not shown) via a pipe 26 connected by a pipe joint 25.

When flushing the steam turbine having the above structure, the turbine axle 12 is first stopped,
From the external pressure source, a pressurized fluid such as compressed air is press-fitted into the hollow portion 20 of the inflatable seal 18 through the pressurized fluid inlet passage 27 formed by the pipe 26, the pipe joint 25 and the anchor pin 24. By inflating the inflatable seal 18, the inner peripheral surface 18 ′ is brought into close contact with the outer peripheral surface of the turbine axle 12, and the function as the axle seal is provided. Next, the turbine chamber A is evacuated to flush the water piping system. At this time, unlike the non-contact labyrinth seal device 15, the inflatable seal 18 completely seals the turbine chamber A. Since it is not necessary to ventilate the gland seal vapor to the labyrinth seal device 15, it is possible to reliably block the invasion of the outside air into the turbine chamber A that is evacuated.

Therefore, it is not necessary to rotate the turbine axle 12 as in the case where the gland seal steam is ventilated through the labyrinth seal device 15, so it is not necessary to flush the lubricating oil piping system prior to the above-mentioned work. It is possible to perform both flushing at the same time. Further, after the flushing work is completed, the inflatable seal 18 becomes unnecessary, but since the inflatable seal 18 is wound in an annular shape, the split type adapter ring 16 is removed from the housing 11 by removing the bolts 17, 21, 22. The inflatable seal 18 and the adapter ring 16 which are no longer needed can be easily removed on site by releasing the connection of the above. On the contrary, when performing the above-mentioned flushing in the existing steam turbine, the inflatable seal 18 can be attached to the existing steam turbine to perform the flushing by the method of the present invention.

[0012]

As is clear from the above description, according to the present invention, when the turbine chamber is evacuated, the circumference of the turbine axle is completely sealed by the inflatable seal arranged in parallel with the labyrinth seal device. Since it is not necessary to supply the gland seal steam to the labyrinth seal device, the flushing of the water piping system on the turbine chamber side and the lubricating oil piping system on the bearing side can be performed simultaneously or in parallel, so that the flushing period can be reduced. It can be significantly shortened, and the inflatable seal can be easily removed after the flushing is completed, so deterioration of the sealing performance etc. due to constant installation can be prevented and it can be easily applied to existing steam turbines. Can be attached to.

[Brief description of drawings]

FIG. 1 is an explanatory view showing one embodiment of a steam turbine flushing method according to the present invention.

FIG. 2 is an explanatory view showing a structure of an inflatable seal in the above embodiment.

FIG. 3 is an explanatory view showing a structure of a labyrinth seal device.

[Explanation of symbols]

 11 Housing 12 Turbine Axle 14 Throttling Piece 15 Labyrinth Seal Device 16 Adapter Ring 17,21,22 Bolt 18 Inflatable Seal 20 Hollow Part 27 Pressurized Fluid Inlet A A Turbine Chamber

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshiyuki Itai, Yoshiyuki Itai 2-1-1, Niihama, Arai-cho, Takasago, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Takasago Plant (72) Shigeyuki Furudate, 1500 Katayanagi, Sakado, Saitama Prefecture Eagle Industry Saitama Factory Co., Ltd. (56) References JP-A-55-155958 (JP, A)

Claims (1)

[Claims] 1. A labyrinth seal device provided in a housing formed in a shaft hole portion of a casing defining a turbine chamber, the labyrinth seal device having a number of fin-shaped throttle pieces, the inner circumference of which is close to the outer circumference of the turbine axle. A hollow inflatable seal made of a rubber-like elastic material, which is supported by the housing via an adapter ring which is arranged in parallel in the labyrinth seal device and whose outer peripheral portion is divided in the circumferential direction, and which is annularly joined at one position in the circumferential direction, In a steam turbine having a turbine axle sealing device consisting of, the turbine axle is stopped, the inflatable seal is pressurized and brought into close contact with the turbine axle, the turbine chamber is evacuated, and a water piping system on the turbine chamber side is provided. A method for flushing a steam turbine, comprising: