Main path and bypass switching device of once-through boiler water supply system of thermal power plant
By designing a main bypass switching device with buffer tanks and buffer plates in the feedwater system of a DC boiler in a thermal power plant, the water hammer problem was solved, stable switching of the feedwater system was achieved, and the risk of equipment damage was reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2026-04-07
AI Technical Summary
The existing main bypass switching device of the feedwater system of the once-through boiler in thermal power plants is prone to water hammer when switching water circuits, which can cause damage to pipes and equipment, and the switching process is not smooth and fast enough.
A switching device comprising a main pipeline, a bypass pipeline, and a buffer tank was designed. The buffer tank is equipped with a buffer plate and a buffer plate. The design of the buffer plate disperses the energy of the water flow, reduces water hammer impact, and ensures the stability of the water supply system.
It effectively reduces water hammer damage to pipes and equipment, ensures a stable supply of boiler feedwater, and lowers the risk of equipment damage.
Smart Images
Figure CN224094458U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to equipment for thermal power plants, and more particularly to a main bypass switching device for a DC boiler feedwater system in a thermal power plant. Background Technology
[0002] In the feedwater system of a once-through boiler in a thermal power plant, the main feedwater system plays a crucial role in providing a stable water supply to the boiler to ensure its normal operation and steam generation. However, during boiler startup, the feedwater system operates at low load, resulting in poor regulation characteristics of the feedwater control system. Manual switching between the main and bypass systems is typically required to maintain normal water supply. Furthermore, in the event of a fault in the main system, maintenance, or adjustments to special operating conditions, a reliable bypass system must be readily available to ensure a continuous feedwater supply to the boiler and prevent serious safety accidents and production stoppages caused by feedwater interruptions.
[0003] Some existing water supply system main-bypass switching devices suffer from problems such as complex structure and unstable or slow switching process. For example, the switching device is prone to water hammer when switching water circuits, which can damage pipes and equipment and severely shorten their service life. Utility Model Content
[0004] The main objective of this invention is to provide a main circuit bypass switching device for a direct-flow boiler feedwater system in a thermal power plant, in order to solve the problem that existing switching devices are prone to water hammer when switching water circuits, which can damage pipelines and equipment.
[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:
[0006] A main bypass switching device for a once-through boiler feedwater system in a thermal power plant, comprising:
[0007] The main pipeline is connected at both ends to the feedwater inlet of the once-through boiler and the feedwater source, respectively, and a main shut-off valve is installed on the main pipeline.
[0008] A bypass pipeline is connected in parallel with the main pipeline between the feedwater inlet and the feedwater source of the once-through boiler, and a bypass regulating valve is installed on the bypass pipeline.
[0009] A buffer tank is connected to the bypass pipe, and the buffer tank is arranged laterally along its length. A buffer plate is installed inside the buffer tank.
[0010] As a further technical solution, there are multiple buffer plates arranged in the buffer tank along the water flow direction. The overall structure of the buffer plate is long and narrow. A gap for water supply is provided between the side wall of the buffer plate and the inner wall of the buffer tank. The length directions of two adjacent buffer plates are perpendicular.
[0011] As a further technical solution, the buffer plate includes multiple plates that are fixedly connected at obtuse angles along the length direction.
[0012] As a further technical solution, each of the plates is provided with multiple through holes.
[0013] As a further technical solution, a plurality of annular fixing plates are fixedly arranged on the inner wall of the buffer tank, and the plurality of annular fixing plates are arranged along the length direction of the buffer tank, and the plurality of buffer plates are respectively fixedly arranged on the plurality of annular fixing plates.
[0014] As a further technical solution, the annular fixing plate is provided with a plurality of first threaded holes evenly distributed around it, and a plurality of connecting rods are fixedly provided at both ends of the buffer plate along its length. An arc-shaped plate is fixedly provided at the end of the connecting rod away from the buffer plate, and a plurality of second threaded holes are provided on the arc-shaped plate. The second threaded holes coincide with any of the first threaded holes and are locked together by bolts.
[0015] As a further technical solution, water is stored at the bottom of the buffer tank.
[0016] As a further technical solution, the buffer tank is provided with an inlet and an outlet, the bypass regulating valve is located at the inlet of the buffer tank, the outlet is located at the bottom of the buffer tank, and a valve is provided on the outlet.
[0017] As a further technical solution, a check valve is also provided on the bypass pipeline, and the check valve is located at the end of the bypass pipeline near the feedwater inlet of the once-through boiler.
[0018] As a further technical solution, a pressure gauge is installed on the buffer tank, and a level gauge is installed inside the buffer tank.
[0019] The beneficial effects of this utility model are as follows:
[0020] This utility model has a simple structure. By setting up a buffer tank and a buffer plate, when water flows into the buffer tank, the buffer plate can block and divert the water flow, so that the flow rate and pressure of the water flow gradually decrease and tend to stabilize. This effectively reduces water flow impact and pressure fluctuation, thereby ensuring the stability of the water supply system during the switching between the main line and the bypass, and reducing the risk of damage to boiler equipment. Attached Figure Description
[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0022] Figure 1 This is a schematic diagram of the process structure of this utility model;
[0023] Figure 2 This is a three-dimensional structural diagram of the internal structure of the buffer tank of this utility model after it has been cut open.
[0024] Figure 3 This is a cross-sectional structural diagram of the buffer tank of this utility model;
[0025] Figure 4 This is a three-dimensional structural diagram of the buffer plate of this utility model.
[0026] Explanation of reference numerals in the attached figures
[0027] 1. Main pipeline; 2. Main shut-off valve; 3. Bypass pipeline; 4. Bypass regulating valve; 5. Buffer tank; 6. Buffer plate; 61. Plate body; 7. Through hole; 8. Annular fixing plate; 9. First threaded hole; 10. Connecting rod; 11. Arc plate; 12. Second threaded hole; 13. Bolt; 14. Inlet; 15. Outlet; 16. Valve; 17. Check valve; 18. Regulating water pipe. Detailed Implementation
[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Many specific details are set forth in the following description to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
[0029] like Figures 1-4 As shown, this utility model proposes a main-circuit bypass switching device for a DC boiler feedwater system in a thermal power plant, which mainly includes a main pipeline 1, a bypass pipeline 3, and a buffer tank 5.
[0030] The two ends of the main pipeline 1 are connected to the feedwater inlet and the feedwater source of the once-through boiler, respectively. A main shut-off valve 2 is installed on the main pipeline 1. The bypass pipeline 3 is connected in parallel with the main pipeline 1 between the feedwater inlet and the feedwater source of the once-through boiler. A bypass regulating valve 4 is installed on the bypass pipeline 3. A check valve 17 is also installed on the bypass pipeline 3. The check valve 17 is located at the end of the bypass pipeline 3 closest to the feedwater inlet of the once-through boiler, which helps to prevent water in the main pipeline 1 from flowing back into the bypass pipeline 3.
[0031] Buffer tank 5 is connected to bypass pipe 3. Buffer tank 5 is positioned laterally along its length, resulting in a relatively long and gentle flow path for the water inside, allowing for better horizontal dispersion of the energy generated by water hammer. Buffer tank 5 has an inlet 14 and an outlet 15. A bypass regulating valve 4 is located at the inlet 14 of buffer tank 5. A fixed amount of water is always present at the bottom of buffer tank 5 to provide a buffer when water flows in from the inlet 14. The outlet 15 is located at the bottom of buffer tank 5, below the level of the fixed amount of water at the bottom. A valve 16 is installed on the outlet 15. A pressure gauge (not shown in the figure) and a level gauge (not shown in the figure) are installed on buffer tank 5 for real-time monitoring of the pressure and level within buffer tank 5. A regulating water pipe 18 is also provided on one side of the buffer tank 5. The regulating water pipe 18 is located at the height of the quantitative water level at the bottom of the buffer tank 5. A regulating valve (not shown in the figure) is provided on the regulating water pipe 18, which can adjust the quantitative water level at the bottom of the buffer tank 5 by adjusting the inlet and outlet water of the regulating water pipe 18 before the equipment is turned on, so as to ensure that the water at the bottom of the buffer tank 5 is always at the preset amount.
[0032] Buffer plates 6 are installed inside the buffer tank 5. Multiple buffer plates 6 are arranged along the water flow direction within the buffer tank 5. The overall structure of the buffer plate 6 is elongated, meaning its front view is rectangular. A gap is provided between the side wall of the buffer plate 6 and the inner wall of the buffer tank 5 for water to pass through. Adjacent buffer plates 6 are perpendicular in their length direction, allowing the water flow to continuously change direction as it passes through the buffer tank 5. When water hammer occurs, the impact force of the water flow is decomposed into different directions, effectively reducing the overall impact energy of the water flow. The buffer plate 6 comprises multiple plates 61 fixedly connected at obtuse angles along its length, forming a zigzag shape. This effectively disperses the impact force of the water flow. Furthermore, the zigzag shape of the buffer plate 6 increases the contact area between the water flow and the buffer plate 6, prolonging the time the water flow acts on the buffer plate 6, thus better consuming the energy of the water flow. Each plate 61 has multiple through holes 7. When water flows into the porous buffer plate 6, a portion of the water flows through the through holes 7 and its speed and direction change. This portion of the water flows collides and mixes with the main flow, thus consuming the energy of the water flow. At the same time, the presence of the through holes 7 also allows the pressure in front of and behind the buffer plate 6 to be balanced to a certain extent, further alleviating the pressure of water hammer on the buffer plate 6.
[0033] Multiple annular fixing plates 8 are fixedly installed on the inner wall of the buffer tank 5, arranged along the length of the buffer tank 5. Multiple buffer plates 6 are fixedly installed on the annular fixing plates 8. Specifically, multiple first threaded holes 9 are evenly distributed around the annular fixing plates 8. Multiple connecting rods 10 are fixedly installed at both ends of the buffer plate 6 along its length. An arc-shaped plate 11 is fixedly installed at the end of the connecting rod 10 away from the buffer plate 6. Multiple second threaded holes 12 are opened on the arc-shaped plate 11, and the second threaded holes 12 coincide with any of the first threaded holes 9 and are locked together by bolts 13. The installation of the buffer plate 6 in the buffer tank 5 is completed by locking the arc-shaped plate 11 and the annular fixing plates 8 with bolts 13, which facilitates operation. The multiple first threaded holes 9 evenly distributed around the arc-shaped fixing plates allow two second threaded holes 12 on the arc-shaped plate 11 to correspond to two of the multiple first threaded holes 9 and be locked together, which facilitates adjustment of the installation angle of the buffer plate 6 in the buffer tank 5.
[0034] The structure of the buffer plate 6 inside the buffer tank 5 will generate some resistance to the water flow. However, the impact of this resistance on normal transportation is controllable, which is existing technology and will not be elaborated here. Therefore, the resistance and pressure fluctuations generated by the buffer plate 6 will only reduce the damage of water hammer pressure to pipelines and equipment under normal circumstances, and will not affect the normal downstream transportation of water.
[0035] In this embodiment, during normal operation, the main shut-off valve 2 is open, the bypass regulating valve 4 is closed, and the feedwater is supplied to the DC boiler through the main pipeline 1. When the main pipeline 1 needs maintenance or malfunctions, the main pipeline shut-off valve 2 is closed and the bypass regulating valve 4 is opened. At the moment of switching, the inertia of the water flow in the pipeline will cause the water flow to continue to flow in the original state. However, the characteristics of the new passage are different, causing the water flow to be unable to adapt immediately, resulting in instability. At this time, the unstable water flow enters the bypass pipeline 3 and flows into the buffer tank 5. After the water flow enters the buffer tank 5, it first impacts the first buffer plate 6. Due to the gap between the buffer plate 6 and the tank wall and the through hole 7 on the plate 61, some water flow will continue to flow backward through the gap and through hole 7, while most water flow will be blocked by the buffer plate 6 and its flow direction will be changed. Then it will mix with the water flow that subsequently passes through the gap and through hole 7 and then flow to the second buffer plate 6. This process is repeated. After the action of multiple buffer plates 6, the flow rate and pressure of the water flow gradually stabilize. The stabilized water flow flows out from the outlet 15 of the buffer tank 5, passes through the check valve 17 and enters the once-through boiler, ensuring a stable supply of boiler feedwater. Throughout the process, the pressure and water level in the buffer tank 5 are monitored in real time using pressure gauges and level gauges. The opening degree and other parameters of the bypass regulating valve 4 are adjusted according to the actual situation to ensure the normal operation of the system.
[0036] This embodiment also includes a control unit, which controls the opening and closing and the degree of opening of the main shut-off valve 2 and the bypass regulating valve 4. This is conventional prior art and will not be described in detail here.
[0037] The above description is only a preferred embodiment of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
Claims
1. A main bypass switching device for a direct-flow boiler feedwater system in a thermal power plant, characterized in that, include: The main pipeline (1) is connected at both ends to the feed water inlet and the feed water source of the DC boiler, respectively. A main shut-off valve (2) is installed on the main pipeline (1). Bypass pipe (3), the bypass pipe (3) is connected in parallel with the main pipe (1) between the feed water inlet and the feed water source of the DC boiler, and a bypass regulating valve (4) is provided on the bypass pipe (3). A buffer tank (5) is connected to the bypass pipe (3). The length of the buffer tank (5) is arranged in the transverse direction. A buffer plate (6) is provided inside the buffer tank (5).
2. The main bypass switching device for a once-through boiler feedwater system in a thermal power plant as described in claim 1, characterized in that, There are multiple buffer plates (6) arranged in the buffer tank (5) along the water flow direction. The overall structure of the buffer plate (6) is long and narrow. A gap for water supply is provided between the side wall of the buffer plate (6) and the inner wall of the buffer tank (5). The length directions of two adjacent buffer plates (6) are perpendicular.
3. The main bypass switching device for a once-through boiler feedwater system in a thermal power plant as described in claim 2, characterized in that, The buffer plate (6) comprises a plurality of plates (61) that are fixedly connected at obtuse angles along the length direction.
4. The main bypass switching device for a once-through boiler feedwater system in a thermal power plant as described in claim 3, characterized in that, Each of the plates (61) has multiple through holes (7).
5. The main bypass switching device for a once-through boiler feedwater system in a thermal power plant as described in claim 2, characterized in that, Multiple annular fixing plates (8) are fixedly installed on the inner wall of the buffer tank (5). The multiple annular fixing plates (8) are arranged along the length direction of the buffer tank (5). The multiple buffer plates (6) are respectively fixedly installed on the multiple annular fixing plates (8).
6. The main bypass switching device for a direct-flow boiler feedwater system in a thermal power plant as described in claim 5, characterized in that, The annular fixing plate (8) is provided with a plurality of first threaded holes (9) evenly distributed around it. Both ends of the buffer plate (6) along its length are fixedly provided with a plurality of connecting rods (10). An arc plate (11) is fixedly provided at the end of the connecting rod (10) away from the buffer plate (6). A plurality of second threaded holes (12) are provided on the arc plate (11). The second threaded holes (12) coincide with any of the first threaded holes (9) and are locked by bolts (13).
7. The main bypass switching device for a direct-flow boiler feedwater system in a thermal power plant as described in claim 1, characterized in that, The bottom of the buffer tank (5) contains water.
8. The main bypass switching device for a once-through boiler feedwater system in a thermal power plant as described in claim 1, characterized in that, The buffer tank (5) is provided with an inlet (14) and an outlet (15). The bypass regulating valve (4) is located at the inlet (14) of the buffer tank (5). The outlet (15) is located at the lower part of the buffer tank (5). A valve (16) is provided on the outlet (15).
9. A main bypass switching device for a once-through boiler feedwater system in a thermal power plant as described in claim 1, characterized in that, A check valve (17) is also installed on the bypass pipe (3), and the check valve (17) is located at one end of the bypass pipe (3) near the feedwater inlet of the DC boiler.
10. A main bypass switching device for a once-through boiler feedwater system in a thermal power plant as described in claim 1, characterized in that, A pressure gauge is installed on the buffer tank (5), and a level gauge is installed inside the buffer tank (5).