JPH0666106A - Shaft seal steam temperature control device for steam turbine - Google Patents

Abstract

PURPOSE:To maintain the temperature of a shaft seal steam at a certain level without injecting water into shaft seal steam. CONSTITUTION:A shaft seal steam temperature control device is provided with a temperature sensor for detecting the steam temperature of a low pressure ground part supplying line 4a, and a high temperature steam exhaust pipe 10 connected to a ground steam pipe 4 and opened/closed automatically by a signal from the temperature sensor 9. When the steam temperature of the low pressure ground part supplying line 4a exceeds a restricted value, the high temperature steam exhaust valve 10 is opened, and a part of exhaust steam from a high pressure ground part 2 is discharged from the ground steam pipe 4 so as to maintain the temperature of shaft seal steam at a specified value. It is thus possible to eliminate any water entering into shaft steam, and to prevent generation of rubbing or rotor vibration on the low pressure ground part 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft seal steam supply system for sealing steam in a gland part of a steam turbine, and a shaft seal steam temperature for controlling a temperature of shaft seal steam supplied to a low pressure gland part of a steam turbine. Regarding the control device.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of a conventional shaft-sealing steam control device. Since the exhaust pressure of the condensing turbine is close to vacuum, 1.1ata of steam slightly higher than atmospheric pressure is filled in the middle of the packing land to prevent outside air from flowing into the turbine from the gland. is doing. Therefore, one common gland steam pipe 4 connected to all the packing lands is provided, the low pressure gland portion 3 supplies the shaft sealing steam, and the high pressure gland portion 2 recovers the outflow steam. The pressure of the shaft seal steam of the gland steam pipe 4 is detected by the pressure sensor 8, and the automatic shaft seal steam supply valve 11 and the automatic shaft seal steam exhaust valve 12 connected to the gland steam pipe 4 are controlled to seal the shaft of the gland part. Maintains steam pressure. At the time of starting the turbine, the entire amount of the gland seal steam is supplied from the gland steam pipe 4 via the automatic shaft sealing steam supply valve 11. When the turbine load reaches a certain ratio, the steam outflowing from the backing land causes excess seal steam in the gland steam pipe 4, and the surplus steam is discharged from the gland steam pipe 4 via the automatic shaft sealing steam exhaust valve 12. The steam pressure in the gland steam pipe is kept constant. In FIG. 3, when the temperature of the shaft sealing steam supplied to the low pressure gland part rises excessively, water is injected from the water injection device 5 provided in the gland steam pipe 4 so that the supply steam temperature does not exceed the limit value. Was there. When the pressure of the steam in the gland steam pipe 4 fell below the specified value, the shaft seal steam was supplied from the automatic shaft sealing steam supply valve 11 to keep the pressure of the steam in the gland steam pipe 4 at the specified value. . At the end of the turbine casing, pipes from leak steam pipes (1.03 ata) (not shown) are connected to the outside of the high pressure gland 2 and the low pressure gland 3 in the axial direction to prevent atmospheric air from entering the gland. I have to.

[0003]

In these shaft-sealing systems, conventionally, the pressure control of the shaft-sealing steam has been the main, and the temperature control of the shaft-sealing steam has been the subordinate. However, it is important to control the temperature of the steam in the shaft seal. Generally, when the temperature of the rotor material exceeds 350 to 370 ° C, the rotor strength drops sharply. Further, in the control of the steam temperature by pouring water, it is difficult to obtain a complete mixture of steam and water, which causes a rapid temperature change of the steam due to the inflow of water,
This causes rubbing due to thermal deformation of the low-voltage gland portion 3, rotor vibration due to misalignment of the positional relationship, and erosion of the low-voltage gland portion 3. Further, since the gland packing has a labyrinth structure, the amount of steam leaked from the gland portion tends to increase due to the expansion of the gap over time.

An object of the present invention is to provide a shaft-sealing steam temperature control device which keeps the temperature of the shaft-sealing steam constant without injecting water into the shaft-sealing steam.

[0005]

[Means for Solving the Problems] A shaft sealing steam for a steam turbine, which is provided with a gland steam pipe, a shaft sealing steam supply valve and a shaft sealing steam exhaust valve so as to supply the shaft sealing steam to a gland portion of the steam turbine. In the temperature control device, a temperature sensor for detecting the steam temperature of the low-pressure gland supply line and a high-temperature steam exhaust valve connected to the gland steam pipe and automatically opened / closed by a signal from the temperature sensor are provided, and the low-pressure gland is provided. When the steam temperature of the part supply line exceeds the limit value, the high temperature steam exhaust valve is opened to discharge a part of the steam discharged from the high pressure gland part from the gland steam pipe to keep the shaft seal steam temperature at the specified value. When the pressure of steam in the gland steam pipe falls below a specified value, the shaft seal steam is supplied from the shaft seal steam supply valve to keep the pressure of the steam in the gland steam pipe at a specified value. Te, to achieve the above purpose.

Further, the shaft sealing steam temperature control of the steam turbine provided with a gland steam pipe, an automatic shaft sealing steam supply valve and an automatic shaft sealing steam exhaust valve so as to supply the shaft sealing steam to the gland portion of the steam turbine. In the device, a temperature sensor for detecting the steam temperature of the low-pressure gland portion supply line, and a communication line connected to the gland steam pipe for transmitting a signal from the temperature sensor to the automatic shaft-sealing steam exhaust valve are provided. When the steam temperature in the gland supply line exceeds the limit value,
Open the automatic shaft-sealing steam exhaust valve, discharge a part of the steam discharged from the high-pressure gland part from the gland steam pipe to keep the shaft-sealing steam temperature at a specified value, and the pressure of the steam in the gland steam pipe from the specified value. When the temperature falls, the above object is achieved by supplying the shaft sealing steam from the automatic shaft sealing steam supply valve to maintain the pressure of the steam in the gland steam pipe at a specified value.

[0007]

In the present invention, since water is not used for controlling the temperature of the shaft sealing steam, there is no sudden temperature change of the steam due to the mixing of water as in the conventional case. The steam temperature of the low-pressure gland supply line is monitored by a temperature sensor.If the steam temperature of the low-pressure gland supply line exceeds the specified value, open the high-temperature steam exhaust valve connected to the gland steam pipe to automatically Moreover, by discharging a part of the steam discharged from the high-pressure gland part to the outside of the shaft-sealing system, the temperature of the shaft-sealing steam is lowered and the temperature of the shaft-sealing steam is maintained at a specified value. When the steam pressure in the gland steam pipe decreases, the shaft seal steam is supplied from the shaft seal steam supply valve, and the pressure of the shaft seal steam is maintained at a specified value.

Further, the steam temperature of the low pressure gland supply line is monitored by a temperature sensor, and when the steam temperature of the low pressure gland supply line exceeds a specified value, an automatic shaft seal steam exhaust connected to the gland steam pipe is performed. By automatically opening the valve and discharging a part of the steam discharged from the high-pressure gland part to the outside of the shaft sealing system, the temperature of the shaft sealing steam is lowered and the temperature of the shaft sealing steam is maintained at a specified value. When the pressure of the steam in the gland steam pipe decreases, the shaft sealing steam is supplied from the automatic shaft sealing steam supply valve, and the pressure of the shaft sealing steam is maintained at a specified value.

[0009]

Embodiment 1 FIG. 1 is a configuration diagram showing an embodiment of a shaft-sealing steam temperature control device equipped with a high temperature steam exhaust valve according to the present invention. In FIG.
The same parts as those in FIG. 3 are designated by the same reference numerals. In FIG. 1, the high pressure gland part 2 and the low pressure gland part 3 at the end of the turbine casing are filled with 1.1 ata steam slightly higher than atmospheric pressure from a gland steam pipe 4. Ground steam pipe 4
Is equipped with a manual shaft seal steam supply valve 6 and a shaft seal steam exhaust valve 7. The pressure of the gland steam pipe 4 is detected by a pressure sensor 8, and the shaft seal steam supply valve 6 and the shaft seal steam exhaust valve 7 are opened and closed manually to maintain the shaft seal steam pressure in the gland portion. In the present invention, a temperature sensor 9 for detecting the steam temperature of the low pressure gland part supply line 4a and a high temperature steam exhaust valve 10 connected to the gland steam pipe 4 and automatically opened / closed by a signal from the temperature sensor 9 are provided. . When the steam temperature of the low-pressure gland supply line 4a exceeds the limit value, the high-temperature steam exhaust valve 10 is automatically opened to discharge a part of the steam discharged from the high-pressure gland part 2 from the gland steam pipe 4 to seal the shaft. Keep the steam temperature at the specified value. When the steam pressure in the gland steam pipe 4 drops below the specified value, the shaft seal steam supply valve 6 supplies the shaft seal steam at 200 to 250 ° C. to the gland steam pipe 4 so that Keep the steam pressure at the specified value. In the present invention, since water is not mixed in the shaft sealing steam, a rapid temperature change of the steam does not occur, and since there is no water mixing, there is no concern that erosion occurs in the low pressure gland portion 3.

Embodiment 2 FIG. 2 is a block diagram showing an embodiment of a shaft-sealing steam temperature control device equipped with an automatic shaft-sealing steam supply valve and an automatic shaft-sealing steam exhaust valve according to the present invention. 2, the same parts as those in FIG. 1 are designated by the same reference numerals. In FIG. 2, the gland steam pipe 4 is provided with an automatic shaft sealing steam supply valve 11 and an automatic shaft sealing steam exhaust valve 12. The pressure of the steam in the ground steam pipe 4 is measured by the pressure sensor 8
Then, the automatic shaft seal steam supply valve 11 and the automatic shaft seal steam exhaust valve 12 are controlled to maintain the shaft seal steam pressure in the gland portion. In the present invention, there is provided a temperature sensor 9 for detecting the steam temperature of the low pressure gland supply line 4a, and a communication line 9a for transmitting a signal from the temperature sensor 9 to the automatic shaft-sealing steam exhaust valve 12 for supplying the low pressure gland part. When the steam temperature in the line 4a exceeds the limit value, the automatic shaft seal steam exhaust valve 1
2 is automatically opened to discharge a part of the steam discharged from the high pressure gland part 2 from the gland steam pipe 4 to keep the steam temperature at a specified value. If the steam pressure in the gland steam pipe 4 drops below the specified value, the shaft seal steam supply valve 6 will send 200 to 250
The shaft sealing steam at 0 ° C. is supplied to the gland steam pipe 4, and the steam pressure in the gland steam pipe 4 is maintained at a specified value.

[0011]

According to the present invention, water is not used for controlling the shaft seal steam temperature, and a part of the steam discharged from the high pressure gland is discharged from the gland steam pipe to keep the steam temperature at a specified value. Since there is no sudden temperature change due to the mixing of water in the shaft sealing steam, rubbing or vibration of the rotor is unlikely to occur in the low pressure gland. Further, since there is no mixing of water in the shaft sealing steam, there is no concern that erosion will occur in the low pressure gland. Furthermore, the conventional water injection equipment is unnecessary.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a shaft sealing steam temperature control device for a steam turbine according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a shaft sealing steam temperature control device for a steam turbine according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional shaft sealing steam control device for a steam turbine.

[Explanation of symbols] 1 steam turbine 2 high pressure gland 3 low pressure gland 4 gland steam pipe 4a low pressure gland supply line 6 shaft sealed steam supply valve 7 shaft sealed steam exhaust valve 9 temperature sensor 9a communication line 10 high temperature steam exhaust valve 11 Automatic shaft seal steam supply valve 12 Automatic shaft seal steam exhaust valve

Claims (2)

[Claims] 1. A shaft-sealing steam temperature control device for a steam turbine, comprising a gland steam pipe, a shaft-sealing steam supply valve, and a shaft-sealing steam exhaust valve so as to supply shaft-sealing steam to a gland portion of the steam turbine. , A temperature sensor for detecting the steam temperature of the low pressure gland supply line, and a high temperature steam exhaust valve connected to the gland steam pipe and automatically opened and closed by a signal from the temperature sensor are provided, When the steam temperature exceeds the limit value, the high temperature steam exhaust valve is opened to discharge a part of the steam discharged from the high pressure gland part from the gland steam pipe to keep the shaft sealing steam temperature at the specified value, When the pressure of the steam is reduced below a specified value, the shaft sealed steam is supplied from the shaft sealed steam supply valve to maintain the pressure of the steam in the gland steam pipe at a specified value. Down shaft sealing steam temperature controller. 2. A shaft-sealing steam temperature control for a steam turbine, comprising a gland steam pipe, an automatic shaft-sealing steam supply valve, and an automatic shaft-sealing steam exhaust valve so as to supply shaft-sealing steam to a gland portion of the steam turbine. In the device, a temperature sensor for detecting the steam temperature of the low-pressure gland portion supply line, and a communication line connected to the gland steam pipe for transmitting a signal from the temperature sensor to the automatic shaft-sealing steam exhaust valve are provided. When the steam temperature of the gland supply line exceeds the limit value, the automatic shaft seal steam exhaust valve is opened, and part of the steam discharged from the high pressure gland part is discharged from the gland steam pipe to specify the shaft seal steam temperature. When the steam pressure in the gland steam pipe falls below the specified value, the steam pressure in the gland steam pipe is maintained at the specified value by supplying the shaft seal steam from the automatic shaft seal steam supply valve. Shaft seal steam temperature control system for a steam turbine, characterized.