Flue gas backflow device for improving heat efficiency of boiler

Abstract

The utility model relates to the technical field of flue gas backflow, in particular to a flue gas backflow device capable of improving heat efficiency of a boiler, which comprises a bottom plate, a gas inlet pipe is arranged on the bottom plate, the other end of the gas inlet pipe is communicated with a communicating pipe, a support is fixedly connected to the side surface of the communicating pipe, and fan blades are rotatably connected to the inner surface of the support. The fan blades are located on the inner wall of the communicating pipe, three speed reduction baffles are fixedly connected to the inner wall of the communicating pipe, and the other end of the communicating pipe is communicated with a separation pipe. And when the flue gas flow speed fluctuates, impact force can be flexibly buffered, the filter screen can be assisted in resetting, the filter screen can be protected from being damaged by high-speed airflow, the service life of quick-wear parts is prolonged, and the shutdown maintenance frequency caused by part faults is reduced.

Description

Technical Field

[0001] This utility model relates to the field of flue gas recirculation technology, specifically to a flue gas recirculation device for improving boiler thermal efficiency. Background Technology

[0002] In flue gas recirculation devices designed to improve boiler thermal efficiency, to prevent dust carried by the flue gas from entering subsequent heat exchangers and causing ash accumulation and blockage of the tube bundles, thus reducing heat exchange efficiency, existing technologies typically incorporate a dust separation stage before the flue gas enters the heat exchanger for purification. However, existing dust separation structures have a core problem in practical applications: when the flue gas exits the boiler and is transported through the inlet pipe and connecting pipe, its velocity is high due to the influence of the fan or airflow dynamics. Furthermore, existing devices lack a targeted flue gas velocity control structure, causing high-speed flue gas carrying dust to quickly pass through the filter screen. Some dust is not fully intercepted and enters the heat exchanger with the flue gas. Long-term operation easily leads to ash accumulation on the surface of the heat exchanger tube bundles, directly weakening the heat exchanger's thermal efficiency. In addition to improving heat exchange efficiency, frequent shutdowns for disassembly and cleaning of the heat exchanger are required, which seriously affects the stability of continuous boiler operation. During boiler operation, load fluctuations can cause unstable flue gas velocity. When the velocity increases suddenly, existing filters are mostly fixed installations or only have basic support structures, lacking an effective buffer protection mechanism. High-speed airflow will directly impact the filter, easily causing deformation and damage, shortening the service life of vulnerable parts, requiring frequent filter replacement, and increasing equipment operation and maintenance costs. When the flue gas velocity drops suddenly, the existing structure cannot assist the filter in resetting to maintain a stable filtration gap, further leading to fluctuations in dust separation effect and making it difficult to continuously ensure the cleanliness of the flue gas entering the heat exchanger.

[0003] Therefore, a flue gas recirculation device to improve boiler thermal efficiency is proposed to solve the problems mentioned above. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides a flue gas recirculation device for improving boiler thermal efficiency. This device can solve the problem of flue gas recirculation in improving boiler thermal efficiency. Existing filters are mostly fixed installations or only have basic support structures, lacking effective buffer protection mechanisms. High-speed airflow will directly impact the filter, easily causing deformation and damage, shortening the service life of vulnerable parts, requiring frequent filter replacement, and increasing equipment operation and maintenance costs.

[0005] To achieve the above objectives, this utility model provides the following technical solution: It includes a base plate, on which an air inlet pipe is provided. The other end of the air inlet pipe is connected to a connecting pipe. A bracket is fixedly connected to the side surface of the connecting pipe. A fan blade is rotatably connected to the inner surface of the bracket. The fan blade is located on the inner wall of the connecting pipe. Three deceleration baffles are fixedly connected to the inner wall of the connecting pipe. A separation pipe is connected to the other end of the connecting pipe. A fixing rod is fixedly connected to the inner wall of the separation pipe. A damper is fixedly connected to the other end of the fixing rod. A spring is fixedly connected to the outer surface of the damper. A filter screen is fixedly connected to the other end of the damper. The filter screen is slidably connected to the inner wall of the separation pipe. A dust removal port is provided on the separation pipe. A limit ring is fixedly connected to the outer surface of the separation pipe. A protective cover is slidably connected to the outer surface of the separation pipe. A heat exchanger is fixedly connected to the other end of the separation pipe.

[0006] Preferably, a button is provided on the outer surface of the air intake pipe, and the button is located above the bracket.

[0007] Preferably, a support leg is fixedly connected to the lower surface of the base plate, and a base is fixedly connected to the lower surface of the support leg.

[0008] Preferably, the base is provided with a flexible board, and the flexible board is made of rubber.

[0009] Preferably, the limiting ring is provided with an insertion hole, and the cover is provided with a pin, the pin being slidably connected to the inner surface of the insertion hole.

[0010] Preferably, the base plate and the support leg are provided with threaded holes, and the inner surface of the threaded holes is threaded with nuts.

[0011] Preferably, a motor is fixedly connected to the outer surface of the bracket, and the fan blades are driven by the motor.

[0012] Compared with the prior art, this utility model provides a flue gas recirculation device to improve boiler thermal efficiency, which has the following beneficial effects:

[0013] 1. By using a heat exchanger to precisely heat the waste heat of the purified flue gas to heat the boiler's combustion air, the traditional boiler process of consuming additional fuel to heat ambient air is directly replaced, effectively reducing fuel consumption, reducing boiler heat loss from the source, significantly improving boiler thermal efficiency, and significantly reducing enterprise energy costs in the long run, meeting the production needs of energy conservation and carbon reduction.

[0014] 2. The deceleration baffle and large-diameter separation pipe can slow down the flue gas flow rate, creating sufficient conditions for the filter screen to intercept dust and impurities, preventing dust from entering the heat exchanger with the flue gas and causing ash accumulation and blockage, and ensuring continuous and efficient heat exchange of the heat exchanger.

[0015] 3. The linkage design of spring and damper can flexibly buffer the impact force when flue gas velocity fluctuates and assist the filter screen to reset. This not only protects the filter screen from damage by high-speed airflow and extends the service life of vulnerable parts, but also reduces the frequency of downtime maintenance due to component failure and lowers equipment operation and maintenance costs. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the main structure of this utility model;

[0017] Figure 2 This is a schematic diagram of the top cross-sectional structure of this utility model;

[0018] Figure 3 This is a schematic diagram of the left-side structure of this utility model;

[0019] Figure 4 This is a partially enlarged structural schematic diagram of the present invention.

[0020] In the diagram: 1. Inlet pipe; 2. Motor; 3. Bracket; 4. Base plate; 5. Nut; 6. Threaded hole; 7. Support leg; 8. Base; 9. Flexible plate; 10. Heat exchanger; 11. Insertion hole; 12. Limiting ring; 13. Pin; 14. Protective cover; 15. Separator pipe; 16. Connecting pipe; 17. Button; 18. Fan blade; 19. Speed ​​reduction baffle; 20. Filter screen; 21. Spring; 22. Damper; 23. Fixing rod; 24. Dust collection port. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] Example:

[0023] Please see Figure 1 - Figure 4 This embodiment of a flue gas recirculation device for improving boiler thermal efficiency includes a base plate 4, an air inlet pipe 1 on the base plate 4, a connecting pipe 16 at the other end of the air inlet pipe 1, a bracket 3 fixedly connected to the side surface of the connecting pipe 16, a fan blade 18 rotatably connected to the inner surface of the bracket 3, the fan blade 18 being located on the inner wall of the connecting pipe 16, a motor 2 fixedly connected to the outer surface of the bracket 3, the fan blade 18 being driven by the motor 2, a button 17 being provided on the outer surface of the air inlet pipe 1, the button 17 being located above the bracket 3, and three deceleration baffles 19 fixedly connected to the inner wall of the connecting pipe 16.

[0024] The operator introduces the flue gas generated by the boiler into the inlet pipe 1. The flue gas then enters the connecting pipe 16 through the inlet pipe 1. The operator then presses button 17 to start motor 2. The control method of button 17 is as follows: pressing button 17 energizes the coil, closes the main contacts, and starts the motor; releasing the button de-energizes the coil and stops the motor. Motor 2 drives the fan blades 18 to rotate, causing the flue gas to quickly pass through the connecting pipe 16. At the end of the connecting pipe 16, a deceleration baffle 19 slows down the flue gas. As the flue gas flows axially within the connecting pipe, it first impacts the lower... A first baffle directly blocks the main flow direction, forcing it to change direction. The kinetic energy of the flue gas is initially consumed due to the change in direction and friction and collision with the baffle, resulting in a decrease in flow velocity. The decelerated flue gas continues to flow upward and encounters a second baffle in the middle, further dissipating the remaining kinetic energy and reducing the flow velocity even further. After being decelerated by the first two baffles, the flue gas reaches the third baffle above. Ultimately, as the flue gas passes through the entire connecting pipe, it gradually reduces its flow velocity through the layers of baffles, path bends, and energy dissipation, achieving a deceleration effect.

[0025] The other end of the connecting pipe 16 is connected to the separation pipe 15. The inner wall of the separation pipe 15 is fixedly connected to the fixing rod 23. The other end of the fixing rod 23 is fixedly connected to the damper 22. The outer surface of the damper 22 is fixedly connected to the spring 21. The other end of the damper 22 is fixedly connected to the filter screen 20. The filter screen 20 is slidably connected to the inner wall of the separation pipe 15. The other end of the separation pipe 15 is fixedly connected to the heat exchanger 10.

[0026] Heat exchanger 10 is an existing device. It adopts a horizontal tubular structure suitable for flue gas recirculation scenarios, with a corrosion-resistant carbon steel shell and stainless steel staggered tube bundles as the core heat exchange elements. Internal baffles are installed, and flue gas and air side tube boxes are located at both ends, sealed with asbestos gaskets and supported by a bottom bracket, balancing resistance to minor ash accumulation and ease of maintenance. Its working principle is indirect heat exchange. The purified flue gas discharged from the device's separation pipe enters the shell, is guided by baffles to laterally flush the outer wall of the tube bundle and release residual heat. Heat is conducted through the tube wall to the inside of the tubes. Room temperature combustion air flows through the inside of the tube bundle, absorbs heat, and enters the boiler combustion chamber. No additional fuel is needed to heat the air, directly reducing heat exchange. Fuel consumption is the core objective of improving boiler thermal efficiency. After the flue gas reaches the separation pipe 15, the diameter of the separation pipe 15 is larger than that of the connecting pipe 16, which makes the flue gas speed slower. The flue gas slowly passes through the filter screen 20, and the dust and impurities in the flue gas are intercepted by the filter screen 20. When the flue gas speed is high, the spring 21 and the damper 22 can protect the filter screen 20. When the flue gas speed is high, the flue gas generates a thrust on the filter screen 20 in the direction of airflow. The spring 21 connected to the filter screen 20 will be compressed accordingly, converting the instantaneous kinetic energy of the flue gas into elastic potential energy, buffering the hard impact that may have caused the filter screen frame to deform or the filter screen to tear, and preventing it from being damaged due to instantaneous overload.

[0027] Simultaneously, the damper 22 moves synchronously with the compression and reset of the spring. Through the friction and throttling effect of the internal damping medium, it generates reverse resistance, converting the mechanical energy of the reciprocating vibration of the filter screen 20 into heat energy dissipation, rapidly attenuating the vibration amplitude and frequency, and preventing fatigue cracks at the weld joints and fiber breakage of the filter screen 20 due to long-term vibration. The two work together to protect the filter screen 20 from the aspects of buffering instantaneous impact and suppressing reciprocating vibration. When the flue gas velocity is low, the spring 21 will rebound to reset the filter screen 20. When the flue gas velocity is low, its thrust on the filter screen 20 is weakened and less than the elastic restoring force of the spring 21. At this time, the originally compressed spring 21 will release the stored elastic potential energy, generating a reverse thrust opposite to the airflow direction, pushing the filter screen 20 to move back to the initial working position.

[0028] Simultaneously, the damper 22 works synchronously with the reset movement of the filter screen 20. Through the friction and throttling effect of the internal damping medium, it suppresses the overshoot and reciprocating vibration that may be caused by the rebound of the spring 21. This allows the filter screen 20 to move smoothly under the restoring force of the spring 21 and the steady-speed action of the damper 22, and finally return to its initial position precisely. This ensures the normal operation of the filtration function. The purified flue gas enters the heat exchanger 10 to heat the boiler's combustion air, so that the boiler does not need to consume additional fuel to heat it from room temperature to working temperature, directly reducing the boiler's fuel consumption and improving thermal efficiency.

[0029] A dust removal port 24 is provided on the separation tube 15. A limit ring 12 is fixedly connected to the outer surface of the separation tube 15. A protective cover 14 is slidably connected to the outer surface of the separation tube 15. An insertion hole 11 is provided on the limit ring 12. A pin 13 is provided on the protective cover 14. The pin 13 is slidably connected to the inner surface of the insertion hole 11. A support leg 7 is fixedly connected to the lower surface of the base plate 4. A base 8 is fixedly connected to the lower surface of the support leg 7. A flexible plate 9 is provided on the base 8. The flexible plate 9 is made of rubber. Threaded holes 6 are provided on both the base plate 4 and the support leg 7. Nuts 5 are threadedly connected to the inner surface of the threaded holes 6.

[0030] Among them, the operator can pull the cover 14 through the dust removal port 24 to clean the dust on the filter screen 20 and prevent the dust from clogging the filter screen 20 and causing the flue gas to not flow. The base 8 can increase the contact area between the support leg 7 and the ground, making the device more stable when running. The rubber soft plate 9 can reduce the noise generated by the friction between the base 8 and the ground when the device is running.

[0031] The working principle of the above embodiment is as follows: When the flue gas reaches the end of the connecting pipe 16, the deceleration baffle 19 slows down the flue gas. After the flue gas runs to the separation pipe 15, the diameter of the separation pipe 15 is larger than that of the connecting pipe 16, making the flue gas speed slower. The flue gas slowly passes through the filter screen 20. The dust and impurities in the flue gas are intercepted by the filter screen 20. When the flue gas speed is relatively fast, the spring 21 and the damper 22 can protect the filter screen 20. When the flue gas speed is relatively low, the spring 21 will rebound to reset the filter screen 20. The purified flue gas enters the heat exchanger 10 to heat the combustion air of the boiler, reducing the fuel consumption of the boiler and improving the thermal efficiency.

[0032] During operation, the operator introduces the flue gas generated by the boiler into the inlet pipe 1. The flue gas then enters the connecting pipe 16 through the inlet pipe 1. Subsequently, the operator presses button 17 to start the motor 2. The motor 2 drives the fan blades 18 to rotate, causing the flue gas to pass quickly through the connecting pipe 16. When the flue gas reaches the end of the connecting pipe 16, the deceleration baffle 19 slows down the flue gas. After the flue gas reaches the separation pipe 15, the diameter of the separation pipe 15 is larger than that of the connecting pipe 16, making the flue gas speed even slower. The flue gas slowly passes through the filter screen 20, where dust and impurities in the flue gas are intercepted. When the flue gas flow rate is high, the spring 21 and the damper 22 can protect the filter screen 20. When the flue gas flow rate is low, the spring 21 will rebound to reset the filter screen 20. The purified flue gas enters the heat exchanger 10 to heat the boiler's combustion air, so that the boiler does not need to consume additional fuel to heat itself from room temperature to operating temperature, directly reducing the boiler's fuel consumption and improving thermal efficiency.

[0033] The installation, connection, or setting methods disclosed in this embodiment are all common mechanical connection methods. As long as they can achieve their beneficial effects, they can be implemented. Therefore, this embodiment will not elaborate on their specific structural composition and working principle.

[0034] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A flue gas recirculation device for improving boiler thermal efficiency, characterized in that: Includes a base plate (4), on which an air intake pipe (1) is provided. The other end of the air intake pipe (1) is connected to a connecting pipe (16). A bracket (3) is fixedly connected to the side surface of the connecting pipe (16). A fan blade (18) is rotatably connected to the inner surface of the bracket (3). The fan blade (18) is located on the inner wall of the connecting pipe (16). Three deceleration baffles (19) are fixedly connected to the inner wall of the connecting pipe (16). The other end of the connecting pipe (16) is connected to a separation pipe (15). A fixing rod (23) is fixedly connected to the inner wall of the separation pipe (15). A damper (22) is fixedly connected to the other end of the fixed rod (23). A spring (21) is fixedly connected to the outer surface of the damper (22). A filter screen (20) is fixedly connected to the other end of the damper (22). The filter screen (20) is slidably connected to the inner wall of the separation tube (15). A dust removal port (24) is provided on the separation tube (15). A limit ring (12) is fixedly connected to the outer surface of the separation tube (15). A cover (14) is slidably connected to the outer surface of the separation tube (15). A heat exchanger (10) is fixedly connected to the other end of the separation tube (15).

2. The flue gas recirculation device for improving boiler thermal efficiency according to claim 1, characterized in that: A button (17) is provided on the outer surface of the air intake pipe (1), and the button (17) is located above the bracket (3).

3. The flue gas recirculation device for improving boiler thermal efficiency according to claim 1, characterized in that: The lower surface of the base plate (4) is fixedly connected to a support leg (7), and the lower surface of the support leg (7) is fixedly connected to a base (8).

4. A flue gas recirculation device for improving boiler thermal efficiency according to claim 3, characterized in that: A flexible plate (9) is provided on the base (8), and the flexible plate (9) is made of rubber.

5. A flue gas recirculation device for improving boiler thermal efficiency according to claim 1, characterized in that: The limiting ring (12) is provided with a socket (11), and the cover (14) is provided with a pin (13), which is slidably connected to the inner surface of the socket (11).

6. The flue gas recirculation device for improving boiler thermal efficiency according to claim 1, characterized in that: The base plate (4) and the support leg (7) are both provided with threaded holes (6), and the inner surface of the threaded hole (6) is threaded with a nut (5).

7. A flue gas recirculation device for improving boiler thermal efficiency according to claim 1, characterized in that: The outer surface of the bracket (3) is fixedly connected to a motor (2), and the fan blade (18) is driven by the motor (2).

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