JPS6172802A - Condensing turbine shaft sealing equipment - Google Patents

Abstract

PURPOSE:To obtain constant proper cooling of shaft sealing steam by forming a shaft sealing main pipe, into which high temperature high pressure steam is introduced, by means of both a main passage and a vertical passage that extends from its middle part downward together with arranging a water- spraying nozzle in the vicinity of the connecting part between both passages. CONSTITUTION:In a condensing turbine 1, in which shaft sealing of the turbine shaft 2 is performed by high and low pressure part glands 3 and 4 consisting of labyrinth packings, a shaft sealing main pipe 10 is formed by both the main passage 10a and a vertical passage 10b. In the vicinity of the connecting part between both passages 10a and 10b is arranged a water spray nozzle 11, while the bottom part of the vertical passage 10b is connected to a drain passage 14. The main passage 10a is interposed into a shaft sealing passage 16, which connects the gland 3 to the gland 4, and the part of the passage 16, which is located between the high pressure part gland 3 and the main passage 10a, is connected to a condenser 9 via a branch passage 19, in which an exhaust control equipment 20 is interposed. The vertical passage 10b is connected to a steam supply passage 5 via a supply passage 17, in which steam supply control equipment 18 is interposed.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of Industrial Application The present invention relates to a shaft sealing device for a condensing turbine for sealing between a turbine shaft and a fixed part.

(2) Prior Art Conventionally, in large condensing turbines, a labyrinth packing is provided at the part where the turbine shaft passes through the casing or the partition plate, and shaft sealing steam at a pressure higher than atmospheric pressure is supplied to the packing gland. Prevents air from entering the package from the outside. This is because the labyrinth packing alone cannot provide complete shaft sealing.

Shaft-sealed steam is supplied to the packing gland by supplying external steam to both the high-pressure gland and low-pressure gland when the condensing turbine is under low load, and by supplying external steam to both the high-pressure gland and low-pressure gland when the condensing turbine is under high load. without introducing
This is done by supplying leaked steam from the high pressure gland to the low pressure gland.

(3) Problems to be solved by the invention However, due to constraints arising from equipment, piping systems, etc., external steam, which is introduced as shaft sealing steam when the condensing turbine is under low load, must be introduced from a high-temperature steam supply source. There are cases. Unfortunately, when the condensate turbine is under high load, the steam leaking from the high-pressure gland may be high-temperature. If such high-temperature steam is used as shaft sealing steam, it may cause problems such as damage to the packing gland, so such steam must be cooled before being supplied to the packing gland.

(4) Object of the Invention The object of the present invention is to provide a condensing turbine with a simple structure, which can reliably cool high-temperature shaft sealing steam and supply it to the packing both at low load and high load of the condensing turbine. An object of the present invention is to provide a shaft sealing device for a turbine.

(5) Means for Solving Problems The shaft sealing device for a condensing turbine of the present invention has the following configuration. In other words, the main passage and the vertical passage extending downward from the middle of the main passage form a shaft-sealed main pipe, and inside the shaft-sealed main pipe, there is a main passage near the communication part between the main passage and the vertical passage. Install a water injection nozzle.

This water injection nozzle is connected to a water supply pipe. Further, a drain discharge passage that can be opened and closed is connected to the bottom of the vertical passage. The main passage of the shaft-sealed main pipe with such a configuration is interposed in the shaft-sealed steam passage that connects the high-pressure gland and the low-pressure gland of the condensing turbine, and the vertical passage is connected to the steam supply passage. . Steam is supplied to this steam supply passage during low load operation of the condensing turbine, and steam is shut off during high load operation.

(6) Operation During low-load operation of the condensing turbine, external steam is supplied from the steam supply passage into the vertical passage of the shaft-sealed main pipe. The amount of external steam supplied can be controlled by an air supply control device. External steam flowing into the vertical passage is cooled by cooling water sprayed by the water injection nozzle, and then enters the main passage. The main passage leads to the high-pressure gland and the low-pressure gland through the shaft-sealed steam passage, and prevents atmospheric air from entering the labyrinth packings of both glands.

On the other hand, during high-load operation of the condensate turbine, the air supply control device detects the high-load operation state and automatically closes.
External steam is prevented from flowing into the shaft-sealed header tube. Then,
The high-pressure gland of the condensing turbine is connected to the low-pressure gland via the shaft-sealed steam supply passage and the main passage of the shaft-sealed main pipe, so high-temperature steam leaking from the high-pressure gland is transferred to cooling water sprayed by the water injection nozzle. After being cooled down, it reaches the low pressure ground. This prevents atmospheric air from entering the labyrinth bag of the low-pressure gland.

(7) Embodiment An embodiment of the apparatus of the present invention will be described below with reference to the drawings.

The shaft seal of the turbine shaft l of the condensing turbine 1 includes a high-pressure part gland 3 and a low-pressure part gland 4 composed of labyrinth packings.
It is done with. Reference numeral 5 denotes a high-temperature, high-pressure steam supply piping for rotating the condensing turbine 1. 1-1 This piping 5 is connected to the turbine high-pressure section by a steam inflow pipe 7 in which a steam control valve 6 is interposed. On the other hand, the turbine low pressure section is connected to a condenser 9 via a steam outlet pipe 8.

The shaft-sealed main tube 10 consists of a main passage 10a and a vertical passage 10b, and the vertical passage 10b extends downward from a midway part of the main passage 10a. A water injection nozzle 11 is disposed inside the shaft-sealed main pipe 10 near a communication portion between the main passage 10a and the vertical passage 10b, and the water injection nozzle 11 is connected to a water supply pipe 12.

16 is a manual valve installed in the water supply pipe 12. On the other hand, a drain discharge passage 14 is connected to the bottom of the vertical passage 10b, and a manual valve 15 is also interposed in the drain discharge passage 14.

The main passage 10a of the shaft-sealed main pipe 10 is interposed in a shaft-sealed steam passage 16 that communicates the high-pressure part gland 3 and the low-pressure part gland 4. The vertical passage 1o1] is the steam supply passage 17
It is connected to the high-temperature, high-pressure steam supply piping 5 through the passage 17, and an air supply control device 18 is interposed in the passage 17. A portion of the shaft-sealed steam passage 16 between the high-pressure part gland 3 and the main passage 10a is connected to the condenser 9 via a branch passage 19.
The branch passage 19 is connected to the exhaust control device 2.
0 is inserted.

The action will be explained below.

FIG. 1 shows the flow of shaft-sealed steam when the condensing turbine is in a low load operating condition. At this time, air supply control 1
8 automatically opens the valve when the turbine is operating at low load;
The high-temperature, high-pressure steam in the pipe 5 is caused to flow into the vertical passage 1 [Ib of the shaft-sealed main tube 10 through the passage 17. The steam that has flowed into the passage 10b rises, is cooled by the cooling water sprayed by the water injection nozzle 11, and then flows into the main passage 10a. The high-pressure part gland 3 passes through the shaft-sealed steam passage 16.
and reaches the low-pressure part gland 4, and seals the shafts of both glands. The air supply control device 18 (d) also detects the flow rate of steam flowing through the main passage 10a and adjusts the opening of the valve installed in the passage 17. The control device 20 closes the passage 19.

FIG. 2 shows the flow of shaft-sealed steam when the condensing turbine is in a high-load operating state. When the turbine 1 is in a high load operating state, the air supply control device 18 blocks the passage 17. During high-load operation, the high-pressure gland 6 of the turbine 1
High-temperature guard steam leaks from the shaft, and the guard steam flows into the main passage 10a of the shaft-sealed main tube 10 through the passage 16. The steam flowing into the main passage 10a is cooled by the cooling water sprayed by the water injection nozzle 11, and flows in the direction of the arrow in FIG. It then passes through the passage 1116 to reach the low-pressure gland 4, and seals the shaft of the low-pressure gland 4. At this time, the exhaust control device 20 detects the steam flow rate in the main passage 10a and controls the opening/closing of the valve installed in the branch passage 19 (8) to detect if the steam flow rate in the main passage 10a is excessive. makes a part of the sanitary steam flow into the condenser 9.

Note that the manual valve 16 is kept open at all times when the turbine 1 is in operation. Moreover, if all the drain in the shaft-sealed main tube 10 is diverted to the bottom of the vertical passage 10b and the valve 15 is opened, this drain can be discharged through the passage 14.

According to the above, even when high-temperature sealing steam must be used, the sealing steam can be reliably cooled regardless of the load condition of the turbine. The effect is that the shaft can be reliably sealed.

In addition, since the shaft sealing steam can be cooled by the cooling water sprayed from the common water injection nozzle both when the turbine is under high load and when the load is low, the structure is simple and maintenance and inspection are easy.

Furthermore, since the drain flows into the vertical passage and accumulates at the bottom, it is possible to easily and reliably collect the drain, and it is also possible to reliably prevent the drain from flowing into the packing gland. obtain.

Further, while the turbine is in operation, water is constantly supplied to the water injection nozzle, and there is no need to perform on/off control of the water supply, so there is also an effect that breakdowns are less likely to occur.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of the present invention device in a turbine low load state. Fig. 2 is a schematic configuration diagram of the present invention device in a turbine high load state. 1: Condensing turbine 2: Turbine shaft 3: High pressure part gland 4: Low pressure part gland 5: High temperature, high pressure steam supply piping 10: Shaft seal main pipe 10a: Main passage 10b: Vertical passage 11: Water injection nozzle 12: Water supply pipe 14: Drain discharge passage 16: Shaft-sealed steam passage 17: Steam supply passage 18: Air supply control device

Claims (1)

[Scope of Claims] 1) A shaft-sealed main pipe is formed by a main passage and a vertical passage extending downward from a midway part of the main passage, and the main passage is connected to a high-pressure part gland and a low-pressure part of the condensing turbine. The vertical passage is interposed in a shaft-sealed steam passage communicating with the ground, and the vertical passage is connected to a steam supply passage, and steam is supplied to the steam supply passage during low load operation of the condensing turbine, and steam is supplied during high load operation of the condensing turbine. An air supply control device for shutting off is interposed, a water injection nozzle is disposed near a communication portion between the main passage and the vertical passage in the shaft-sealed main pipe, and a water supply pipe is connected to the water injection nozzle at the bottom of the vertical passage. A shaft sealing device for a condensing turbine, characterized in that a drain discharge passage that can be opened and closed is connected to the shaft sealing device. 2) The shaft of a condensing turbine according to claim 1, wherein the air supply control device detects the steam flow rate in the main passage and controls the steam supply amount during low-load operation of the steam turbine. Sealing device. 3) In the statement of claim 1, a portion of the shaft-sealed steam passage connecting the high-pressure part gland and the main passage is connected to the condenser of the condensing turbine via a branch passage; A condensing turbine shaft sealing device comprising an exhaust control device interposed in the branch passage, which closes the branch passage during low load operation of the condensing turbine and controls a steam flow rate in the branch passage during high load operation.