CN214304508U

CN214304508U - Water feed pump sealing system of thermal power plant

Info

Publication number: CN214304508U
Application number: CN202023280726.5U
Authority: CN
Inventors: 陈希龙
Original assignee: China Resources Power Changshu Co Ltd
Current assignee: China Resources Power Changshu Co Ltd
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2021-09-28
Anticipated expiration: 2030-12-30

Abstract

The utility model provides a feed pump sealing system of thermal power plant which characterized in that: comprises a labyrinth seal, a bearing and a water seal; the labyrinth seal comprises a bush and a pump shaft, the bush is sleeved on the pump shaft and arranged at intervals, and the bush is sequentially provided with an unloading water chamber, a sealing water chamber and a non-pressure water return chamber from inside to outside along the axial direction of the pump shaft; the bearing comprises a bearing bush and an oil seal, the bearing bush is sleeved on the outer side of the pump shaft, a sewage discharging cavity is further arranged between the bearing and the labyrinth seal in the axial direction, the oil seal is arranged between the sewage discharging cavity and the bearing bush, a breather is arranged at the top of the sewage discharging cavity and communicated with the atmosphere, drainage equipment is arranged at the bottom of the sewage discharging cavity and comprises a drainage valve and a drainage fan, and the drainage valve and the drainage fan are respectively connected to the sewage discharging cavity; the water seal comprises a first water return valve, a second water return valve and a water injection valve, the water seal is communicated with the non-pressure water return cavity through the water return valve, the water seal is communicated to the condenser through the second water return valve, and the water seal is communicated to the condensate pump through the water injection valve.

Description

Water feed pump sealing system of thermal power plant

Technical Field

The utility model relates to a water-feeding pump sealing field, in particular to water-feeding pump sealing system of thermal power plant.

Background

At present, a labyrinth seal system is mostly adopted in a seal system of a steam-driven feed pump of a thermal power plant. The basic working principle of the labyrinth seal system is to perform the sealing work of the steam feed water pump in a clearance leakage control mode, and the labyrinth seal system generally comprises three parts, namely a labyrinth seal, a bearing and a water seal. The labyrinth seal and the bearing are generally arranged in the same sealed space, and the middle of the labyrinth seal and the bearing are separated by a sewage discharge chamber.

In actual operation, the labyrinth seal system has the problem of leaking water to the blowdown cavity along the clearance, and on one hand, because labyrinth seal self structural feature, the certain leakage rate can appear along the clearance in the labyrinth seal from the sealing water that condensate pump got into and the water that comes of pump body inside, and this leakage rate changes along with the change of the operating speed of feed water pump and sealing clearance. In the running process of the water supply pump, most leakage amount is discharged to the condenser from the non-pressure return water chamber through the water seal, but a small amount of leakage amount still enters the sewage discharging chamber, the capacity of the sewage discharging chamber is small, and if the leakage amount cannot be discharged in time, the water enters the bearing bush at a high probability;

on the other hand, when the two water feeding pumps are used simultaneously, the discharged water is gathered together before entering the water seal, and the discharged water is influenced mutually to cause unsmooth, so that the water volume entering the sewage discharge chamber is invisibly increased.

Disclosure of Invention

The utility model provides a water-feeding pump sealing system of thermal power plant, the purpose is to solve the current water-feeding pump during operation sealed water and reveal the difficult problem that arouses the tile axle to damage.

In order to solve the above problem, the utility model provides a scheme: the utility model provides a feed pump sealing system of thermal power plant which characterized in that: comprises a labyrinth seal, a bearing and a water seal;

the labyrinth seal comprises a bush and a pump shaft, the bush is sleeved on the pump shaft and arranged at intervals, and the bush is sequentially provided with an unloading water chamber, a sealing water chamber and a non-pressure water return chamber from inside to outside along the axial direction of the pump shaft;

the bearing comprises a bearing bush and an oil seal, the bearing is sleeved on the outer side of the pump shaft, a sewage discharge chamber is further arranged between the bearing and the labyrinth seal along the axial direction, the oil seal is arranged between the sewage discharge chamber and the bearing bush, a breather is arranged at the top of the sewage discharge chamber and communicated with the atmosphere, drainage equipment is arranged at the bottom of the sewage discharge chamber and comprises a drainage valve and a drainage fan, and the drainage valve and the drainage fan are respectively connected to the sewage discharge chamber;

the water seal comprises a first water return valve, a second water return valve and a water injection valve, the water seal is communicated with the non-pressure water return cavity through the water return valve, the water seal is communicated to the condenser through the second water return valve, and the water seal is communicated to the condensate pump through the water injection valve.

Preferably, the water seal further comprises an overflow water pipe.

Preferably, the first water return valves are provided in a plurality and are respectively connected to the non-pressure water return chambers of the water supply pumps.

Wherein, the breather valve can communicate bearing box and atmosphere, and the pressure differential between the inside and the outside of balanced casing prevents the inside condensation of casing, protects casing and inside components and parts to prolong the working life of whole bearing (non the utility model discloses the innovation point).

The normal working path of the labyrinth seal system is that the condensate pump is communicated with the seal water chamber 112, and seal water flowing out of the condensate pump flows out of the non-pressure water return chamber 113 along a gap between the pump shaft 12 and the bushing 11 and enters the water seal 3; in addition, most of the feed water flows out of the unloading water chamber 111, and a part of the feed water flows out of the non-pressure return water chamber 113 along the sealing gap and flows out of the condensate pump into the water seal 3.

The utility model discloses a design principle and effect:

1. this technical scheme improves the blowdown mode of blowdown cavity, connects in parallel at the drain valve of blow off pipe and installs the drainage fan additional, increases the suction capacity to set up a plurality of return valves with the water seal, be connected to the non-pressure return water cavity of several feed pump respectively, get rid of mutual interference, ensure that the return water is unobstructed.

2. The utility model discloses guaranteed that the steam-feed pump no longer gets into the axle bush at full duty cycle internal seal water, prevented that steam-feed pump lubricating oil from taking water in a large number, avoided the axle bush scaling loss occurence of failure.

3. Because the lubricating oil in the oil seal can be taken out when considering that blowdown cavity negative pressure is too big when blowdown cavity delivery pipe installs the drainage fan additional, both increased the lubricating oil loss, cause environmental pollution again, and after the parallel connection installation, can adjust the negative pressure of blowdown cavity through the drain valve, guarantee not take lubricating oil out.

Drawings

FIG. 1 is the utility model discloses the feed pump sealing system schematic diagram of thermal power plant.

In the above drawings: 1. labyrinth sealing; 11. a bushing; 111. an unloading water chamber; 112. sealing the water chamber; 113. a non-pressure backwater chamber; 12. a pump shaft; 2. a bearing; 21. bearing bushes; 22. oil sealing; 3, water sealing; 31. a first water return valve; 32. a second water return valve; 33. a water injection valve; 34. an overflow water pipe; 4. a blowdown chamber; 5. a respirator; 6. a drainage facility; 61. a drain valve; 62. a water discharge fan.

Detailed Description

The invention will be further described with reference to the following drawings and examples:

example (b): water feed pump sealing system of thermal power plant

The utility model provides a feed pump sealing system of thermal power plant which characterized in that: comprises a labyrinth seal 1, a bearing 2 and a water seal 3;

the labyrinth seal 1 comprises a bush 11 and a pump shaft 12, the bush 11 is sleeved on the pump shaft 12 and is arranged at intervals, and the bush 11 is sequentially provided with an unloading water chamber 111, a sealing water chamber 112 and a non-pressure water return chamber 113 from inside to outside along the axial direction of the pump shaft 12;

the bearing 2 comprises a bearing bush 21 and an oil seal 22, the bearing 2 is sleeved on the outer side of the pump shaft 12, a sewage discharge chamber 4 is further arranged between the bearing 2 and the labyrinth seal 1 in the axial direction, the oil seal 22 is arranged between the sewage discharge chamber 4 and the bearing bush 21, a breather 5 is arranged at the top of the sewage discharge chamber 4, the breather 5 is communicated with the atmosphere, drainage equipment 6 is arranged at the bottom of the sewage discharge chamber 4, the drainage equipment 6 comprises a drainage valve 61 and a drainage fan 62, and the drainage valve 61 and the drainage fan 62 are respectively connected to the sewage discharge chamber 4;

the water seal 3 comprises a first water return valve 31, a second water return valve 32 and a water injection valve 33, the water seal 3 is communicated with the non-pressure water return cavity 113 through the water return valve 31, the water seal 3 is communicated to the condenser through the second water return valve 32, and the water seal 3 is communicated to the condensate pump through the water injection valve 33.

The water seal 3 further comprises an overflow pipe 34. The first water return valves 31 are connected to the water supply pump non-pressure water return chambers 113.

The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose of the embodiments is to enable people skilled in the art to understand the contents of the present invention and to implement the present invention, which cannot limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered by the protection scope of the present invention.

Claims

1. The utility model provides a feed pump sealing system of thermal power plant which characterized in that: comprises a labyrinth seal (1), a bearing (2) and a water seal (3);

the labyrinth seal (1) comprises a bush (11) and a pump shaft (12), the bush (11) is sleeved on the pump shaft (12) and arranged at intervals, and the bush (11) is sequentially provided with an unloading water chamber (111), a sealing water chamber (112) and a non-pressure water return chamber (113) from inside to outside along the axial direction of the pump shaft (12);

the bearing (2) comprises a bearing bush (21) and an oil seal (22), the bearing (2) is sleeved on the outer side of the pump shaft (12), a sewage discharge chamber (4) is further arranged between the bearing (2) and the labyrinth seal (1) in the axial direction, the oil seal (22) is arranged between the sewage discharge chamber (4) and the bearing bush (21), a breather (5) is arranged at the top of the sewage discharge chamber (4), the breather (5) is communicated with the atmosphere, drainage equipment (6) is arranged at the bottom of the sewage discharge chamber (4), the drainage equipment (6) comprises a drainage valve (61) and a drainage fan (62), and the drainage valve (61) and the drainage fan (62) are respectively connected to the sewage discharge chamber (4);

the water seal (3) comprises a first water return valve (31), a second water return valve (32) and a water injection valve (33), the water seal (3) is communicated with the non-pressure water return cavity (113) through the water return valve (31), the water seal (3) is communicated to the condenser through the second water return valve (32), and the water seal (3) is communicated to the condensate pump through the water injection valve (33).

2. The sealing system of claim 1, wherein: the water seal (3) also comprises an overflow water pipe (34).

3. The sealing system of claim 1, wherein: the first water return valves (31) are provided with a plurality of pressure-free water return chambers (113) which are respectively connected to the water feeding pumps.