Novel pump warming-up pipe structure for water feeding pump of steam turbine of thermal power plant

Abstract

A novel pump warming-up pipe structure for a steam turbine feed pump of a thermal power plant belongs to the technical field of heating feed pumps. The device comprises a pump warming-up pipe inlet stop valve and a blow-down valve, a plurality of intercepting rods are connected in series at an outlet of the pump warming-up pipe inlet stop valve, the intercepting rod at the end part is connected with one end of a thick-wall elbow through a first connecting pipe, and the other end of the thick-wall elbow is connected with a first port of a three-way pipe through a second connecting pipe; a second port of the three-way pipe is connected to the blow-down valve, and a third port of the three-way pipe is connected to a water feeding pump chamber. The pressure difference between the warm-up pump pipe and the feed pump chamber can be reduced, water flow in the warm-up pump is reduced, washing of a warm-up pump door and a high-pressure side blow-down valve is correspondingly reduced, the service life of the warm-up pump pipe is greatly prolonged, the replacement and maintenance frequency is reduced, meanwhile, it is guaranteed that the feed pump can be in a standby state for a long time, and the service life of the warm-up pump is prolonged. And the stable water supply of the boiler is ensured.

Description

Technical Field

[0001] This utility model belongs to the field of heating water supply pump technology, specifically relating to a novel heating pipe structure for a steam turbine feedwater pump in a thermal power plant. Background Technology

[0002] Feedwater pumps are indispensable equipment for boiler water supply. Thermal power plants typically have five feedwater pumps on the turbine side, operating at a ratio of four in operation and one on standby, or two in operation and three on standby. Before starting, feedwater pumps require warm-up to prevent excessive temperature differences between the top and bottom of the pump casing. This prevents casing deformation, bearing misalignment, rotor bending, contact between moving and stationary parts, increased vibration during startup, wear of moving and stationary parts, and shaft seizure. To ensure the feedwater pump can be started at any time during standby, it needs to be kept at a constant temperature of approximately 135℃ for normal operation. Therefore, each feedwater pump is equipped with a warm-up pipe connected from the feedwater pump outlet valve to the feedwater header, with a welded carbon steel shut-off valve. This pipe connects to the bottom of the feedwater pump and enters the pump chamber. Opening the valve achieves the warm-up effect for the standby feedwater pump, preventing damage caused by temperature differences.

[0003] When the standby feedwater pump is put into operation for warm-up, the pressure in the warm-up pump pipe equals the feedwater pressure of 15 MPa, creating a significant pressure difference with the feedwater pump chamber. This causes leaks to appear in the warm-up pump pipe after approximately 30 days of operation, especially at elbows and the bottom connection of the pump. Because these leaks eject high-temperature, high-pressure jets of water, they can easily cause injury to personnel on site. Simultaneously, the inlet valve also suffers severe internal leakage due to the pressure difference, making it difficult to close completely (requiring more extensive isolation measures), necessitating replacement of the warm-up pump pipe inlet valve. Furthermore, welders face harsh working conditions when repairing welds and replacing pipe sections, with blind spots that compromise weld quality. Each repair requires a significant investment of manpower and time. Utility Model Content

[0004] This invention addresses the aforementioned problems and overcomes the shortcomings of existing technologies by providing a novel warm-up pipe structure for feedwater pumps in steam turbines of thermal power plants. This invention can solve the problem of frequent leaks in the warm-up pipe caused by the large pressure difference between the warm-up pipe and the feedwater pump chamber.

[0005] To achieve the above objectives, the present invention adopts the following technical solution.

[0006] This utility model provides a novel warm-up pipe structure for a steam turbine feedwater pump in a thermal power plant, including a warm-up pipe inlet gate and a drain gate. The inlet gate has multiple flow-stopping rods connected in series at its outlet. Each flow-stopping rod is connected to one end of a thick-walled elbow via a first connecting pipe. The other end of the thick-walled elbow is connected to the first port of a tee pipe via a second connecting pipe. The second port of the tee pipe is connected to the drain gate, and the third port of the tee pipe is connected to the feedwater pump chamber.

[0007] Furthermore, the flow-stopping rod includes a rod body, and the rod body has a flow-stopping hole extending through both ends of the rod body along its central axis. Both ends of the rod body are provided with bevels.

[0008] Furthermore, the slope of the bevel is 30°.

[0009] The beneficial effects of this utility model.

[0010] This invention can reduce the pressure difference between the heating pump pipe and the feed water pump chamber, and reduce the water flow in the heating pump. The scouring of the heating pump door and the high-pressure side drain valve is also reduced accordingly, which greatly extends the service life of the heating pipe, reduces the number of replacements and maintenance, and ensures that the feed water pump can be in standby mode for a long time, thus ensuring the stability of boiler feed water. Attached Figure Description

[0011] To make the technical problems solved, the technical solutions, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0012] Figure 1 This is a schematic diagram of the structure of this utility model.

[0013] Figure 2 This is a cross-sectional structural diagram of a flow-stopping rod according to this utility model.

[0014] The markings in the diagram are as follows: 1 is the inlet valve of the heating pump pipe, 2 is the drain valve, 3 is the flow-stopping rod, 4 is the first connecting pipe, 5 is the thick-walled elbow, 6 is the second connecting pipe, 7 is the tee pipe, 8 is the first port, 9 is the second port, 10 is the third port, 11 is the rod body, 12 is the flow-stopping hole, and 13 is the bevel. Detailed Implementation

[0015] As shown in the accompanying drawings, this embodiment provides a novel warm-up pipe structure for a steam turbine feedwater pump in a thermal power plant, including a warm-up pipe inlet gate 1 and a drain gate 2. Multiple flow-stopping rods 3 are connected in series at the outlet of the warm-up pipe inlet gate 1. Each flow-stopping rod 3 includes a rod body 11. A flow-stopping hole 12 is provided axially through both ends of the rod body 11. Both ends of the rod body 11 are provided with a bevel 13 with a slope of 30° to facilitate welding.

[0016] The function of the throttle rod 3 is to regulate the working state of the liquid pressure by controlling the speed of liquid flow. Specifically, the throttle rod can change the speed of the fluid passing through the throttle holes 12 through the throttle holes, thereby achieving the effect of regulating the system flow rate, pressure and speed.

[0017] By controlling the velocity and pressure of the liquid flowing to the throttle bar 3, the pipeline pressure, system flow rate, pressure, and velocity can be controlled. When the liquid passes through the throttle orifice 12, the flow rate is adjusted by the cross-sectional area of ​​the orifice. Due to the principle of mass conservation, the liquid velocity will inevitably increase when the cross-sectional area decreases. Due to the principle of energy conservation, the pressure will also increase as the liquid velocity increases, thus reducing the pressure difference between the warm-up pump pipe and the feed water pump chamber.

[0018] The end of the flow-stopping rod 3 is connected to one end of the thick-walled elbow 5 through the first connecting pipe 4. The other end of the thick-walled elbow 5 is connected to the first port 8 of the tee pipe 7 through the second connecting pipe 6. The second port 9 of the tee pipe 7 is connected to the drain valve 2. The third port 10 of the tee pipe 7 is connected to the water supply pump room.

[0019] By processing existing conventional, easily worn and eroded elbows into thick-walled elbows 5 and tees 7 using carbon steel thick plates, a double layer of protection is provided for leak prevention, thereby achieving better performance. This ensures the stable and effective backup of the feedwater pump, and ensures that if other pumps suddenly stop in case of emergencies, the backup feedwater pump can be automatically restarted, ensuring a stable water supply to the boiler and avoiding boiler shutdown accidents caused by feedwater pump failure.

[0020] It is understood that the above specific description of this utility model is only used to illustrate this utility model and is not limited to the technical solutions described in the embodiments of this utility model. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to this utility model to achieve the same technical effect; as long as the use needs are met, they are all within the protection scope of this utility model.

Claims

1. A new type of warm pump pipe structure for the feed water pump of a thermal power plant steam turbine, comprising a warm pump pipe inlet cut-off gate (1), a blowdown gate (2), characterized in that, The warm pump pipe inlet cut-off door (1) outlet is connected with multiple cut-off rods (3) in series, the end of the cut-off rod (3) is connected with one end of a thick wall elbow (5) through a first connecting pipe (4), the other end of the thick wall elbow (5) is connected with a first port (8) of a three-way pipe (7) through a second connecting pipe (6), a second port (9) of the three-way pipe (7) is connected to the blowdown door (2), and a third port (10) of the three-way pipe (7) is connected to a water supply pump chamber.

2. A new type of warm pump piping structure for a feed water pump of a steam turbine of a thermal power plant according to claim 1, characterized in that, The cut-off rod (3) comprises a rod body (11), a cut-off hole (12) is arranged in the center axis of the rod body (11) and penetrates both ends of the rod body (11), and a bevel (13) is arranged at both ends of the rod body (11).

3. The new warm pump piping arrangement for a thermal power plant steam turbine feed water pump as claimed in claim 2 wherein, The slope of the bevel (13) is 30°.

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