Three-pass counterflow boiler

Abstract

The utility model relates to small -size boiler technical field, concretely relates to a three return stroke anti -burning boiler, including furnace shell, furnace, second return stroke flue pipe, third return stroke flue pipe and panel. The top of furnace shell is equipped with the first, second smoke chamber in parallel, is equipped with the third smoke chamber in the bottom. The furnace is longitudinally placed under the first smoke chamber, and the bottom is equipped with the ash channel with fire grate. The second return stroke flue pipe surrounds the furnace, and connects the first and third smoke chamber;The third return stroke flue pipe is located under the second smoke chamber, and connects the second and third smoke chamber. The water cavity is formed between the furnace shell and the internal component. The fire grate of the application is composed of fixed row and rotating row, which can easily crush slag and clean ash. The inner wall of the furnace is provided with grooves for enhanced heat exchange. The third smoke chamber is provided with a jet nozzle aligned with the third return stroke flue pipe for blowing off the accumulated ash. The boiler has compact structure, high thermal efficiency, convenient ash removal, energy saving and environmental protection, effectively solving the problems of serious ash accumulation, difficult slag removal and low thermal efficiency of traditional small boilers.

Description

Technical Field

[0001] This utility model relates to the field of small boiler technology, specifically to a three-pass reverse-fired boiler. Background Technology

[0002] Traditional coal-fired boilers typically employ direct combustion or simple return-pass structures, resulting in incomplete combustion, low thermal efficiency, high flue gas temperature, and significant pollution emissions. This is especially true for small boilers, whose grates are often fixed, making ash removal difficult and impacting ventilation and combustion efficiency. Furthermore, after a period of operation, ash easily accumulates inside the flue tubes, making cleaning difficult and leading to decreased heat exchange efficiency and increased energy consumption. Therefore, the market urgently needs a small boiler system that is highly efficient, energy-saving, environmentally friendly, and easy to clean. Utility Model Content

[0003] This utility model provides a three-pass reverse-fired boiler. The boiler has a compact structure, high thermal efficiency, convenient ash removal, energy saving and environmental protection, and effectively solves the problems of serious ash accumulation, difficult slag removal and low thermal efficiency of traditional small boilers.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a three-pass reverse-fired boiler, comprising: a furnace shell, wherein a first flue gas chamber and a second flue gas chamber are arranged side-by-side at the top of the furnace shell, and a third flue gas chamber is arranged at the bottom of the furnace shell; a furnace liner, wherein the furnace liner is longitudinally positioned below the first flue gas chamber, and an ash channel extending horizontally outward from the bottom of the furnace liner is provided, wherein a grate is provided at the top of the ash channel corresponding to the furnace liner, and an ash door is provided at the outer end of the ash channel; and a second-pass flue pipe, wherein the second-pass flue pipe is distributed around the furnace liner, and its two ends are respectively connected to the first flue gas chamber. It is connected to the third flue gas chamber; a third return flue pipe is arranged below the second flue gas chamber, with both ends connected to the second flue gas chamber and the third flue gas chamber respectively; a panel is arranged on the top of the furnace shell, and the panel is provided with a furnace cover corresponding to the first flue gas chamber and a flue gas outlet corresponding to the second flue gas chamber; the furnace shell forms a cavity with the first flue gas chamber, the second flue gas chamber, the third flue gas chamber and the furnace liner, and the top and outer wall of the furnace shell are respectively provided with a water outlet pipe and a water inlet pipe connected to the cavity.

[0005] Preferably, the grate consists of a fixed grate and a rotating grate; the rotating grate includes a rotating shaft that extends horizontally from the bottom of the furnace shell to the outside of the furnace shell, and also includes a plurality of first rows of teeth located inside the furnace shell and perpendicularly connected to the rotating shaft, the plurality of first rows of teeth extending radially on the rotating shaft and forming a support surface together, the rotating shaft being connected to a mechanism for driving its rotation; the fixed grate includes a plurality of second rows of teeth that are horizontally arranged at the bottom of the furnace shell, each of the second rows of teeth being located between any two adjacent first rows of teeth.

[0006] Preferably, the inner wall of the furnace is circumferentially arranged with multiple grooves to increase the heating area and disturb the flue gas.

[0007] Preferably, the third flue gas chamber is equipped with jet nozzles corresponding to the interior of each of the third return flue pipes. The air inlet end of each jet nozzle extends to the outside of the furnace shell through an air supply pipe and is connected to the blower through a one-way valve.

[0008] The beneficial effects of this utility model are as follows:

[0009] 1. High thermal efficiency: The three-pass design greatly extends the flue gas travel and heat exchange time, makes full use of the waste heat of the flue gas, significantly reduces the exhaust gas temperature, and improves thermal efficiency.

[0010] 2. Energy saving and environmental protection: The grooves on the inner wall of the furnace increase the heating area and disturb the flue gas, making the combustion more complete and reducing the loss of incomplete combustion and pollutant emissions.

[0011] 3. Convenient Ash Removal: The unique rotating grate structure solves the pain point of difficult ash removal in small boilers. It is easy to operate and can effectively maintain good ventilation. The jet nozzle soot blowing device can remotely clean the ash accumulation in the third pass flue, avoiding the decrease in efficiency caused by ash accumulation and reducing maintenance workload.

[0012] 4. Compact structure: The second pass flue tubes are arranged around the furnace shell, and the third pass flue tubes are placed below the second flue gas chamber. The structure is reasonable and achieves the maximum heat exchange area in a limited space. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0015] Figure 2 This is a cross-sectional view of the internal structure of this utility model;

[0016] Figure 3 This is a partial structural cross-sectional view of the present invention.

[0017] In the diagram: 1. Furnace shell; 2. First flue gas chamber; 3. Second flue gas chamber; 4. Third flue gas chamber; 5. Furnace liner; 6. Ash door; 7. Second return flue pipe; 8. Third return flue pipe; 9. Panel; 10. Furnace cover; 11. Exhaust port; 12. Chamber; 13. Water outlet pipe; 14. Water inlet pipe; 15. Shaft; 16. First row of teeth; 17. Second row of teeth; 18. Groove; 19. Jet nozzle; 20. Gas supply pipe; 21. One-way valve; 22. Fan. Detailed Implementation

[0018] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. 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.

[0019] according to Figure 1 , Figure 2 , Figure 3 As shown, a three-pass reverse-fired boiler includes: a furnace shell 1, with a first flue gas chamber 2 and a second flue gas chamber 3 arranged side-by-side at the top of the furnace shell 1, and a third flue gas chamber 4 at the bottom of the furnace shell 1; a furnace chamber 5, which is longitudinally positioned below the first flue gas chamber 2, and has an ash channel extending horizontally outward from the bottom of the furnace chamber 5, with a grate corresponding to the top of the ash channel, and an ash door 6 at the outer end of the ash channel; second-pass flue pipes 7, which are distributed around the furnace chamber 5, and are connected at both ends to the first flue gas chamber 2 and the third flue gas chamber 4 respectively; and a third-pass flue pipe... Pipe 8, the third return flue pipe 8 is located below the second flue gas chamber 3, and its two ends are respectively connected to the second flue gas chamber 3 and the third flue gas chamber 4; panel 9, the panel 9 is located on the top of the furnace shell 1, and the panel 9 is provided with a furnace cover 10 corresponding to the first flue gas chamber 2 and a flue gas outlet 11 corresponding to the second flue gas chamber 3; the furnace shell 1 forms a cavity 12 with the first flue gas chamber 2, the second flue gas chamber 3, the third flue gas chamber 4 and the furnace liner 5, and the top and outer wall of the furnace shell 1 are respectively provided with a water outlet pipe 13 and a water inlet pipe 14 connected to the cavity 12.

[0020] Through the above technical solution, the flue gas undergoes three distinct return paths within the boiler. First pass: Fuel burns downwards within the furnace chamber 5, and the high-temperature flue gas rises inside the furnace chamber 5 to the first flue gas chamber 2. This process primarily heats the furnace chamber 5 walls through convection and radiation. Second pass: The high-temperature flue gas is guided to the second pass flue pipe 7 surrounding the furnace chamber 5, flowing downwards into the third flue gas chamber 4. During this process, the high-temperature flue gas undergoes efficient convective heat exchange with the water in the cavity 12 through the flue pipe wall. Simultaneously, due to its arrangement surrounding the furnace chamber 5, it also provides secondary heating to the furnace chamber 5. Third pass: The flue gas reverses course in the third flue gas chamber 4, entering the third pass flue pipe 8 from bottom to top, and finally flows into the second flue gas chamber 3 and exits from the exhaust port 11. This final pass further recovers the waste heat from the flue gas. This "S"-shaped or "Ω"-shaped long-path design significantly extends the flue gas residence time and heat exchange path, allowing for full heat absorption, thereby significantly reducing the exhaust gas temperature and achieving high thermal efficiency.

[0021] The grate consists of a fixed grate and a rotating grate. The rotating grate includes a rotating shaft 15 that extends horizontally from the bottom of the furnace liner 5 to the outside of the furnace shell 1, and also includes a plurality of first teeth 16 located inside the furnace liner 5 and perpendicularly connected to the rotating shaft 15. The plurality of first teeth 16 extend radially from the rotating shaft 15 and together form a support surface. The rotating shaft 15 is connected to a mechanism that drives its rotation. The fixed grate includes a plurality of second teeth 17 that are horizontally arranged at the bottom of the furnace liner 5. Each second tooth 17 is located between any two adjacent first teeth 16.

[0022] When ash removal is required, the shaft 15 is rotated via the handle or drive mechanism, causing all the first row of teeth 16 perpendicularly connected to it to rotate. Since the stationary second row of teeth 17 is located in the gaps between the first row of teeth 16, the rotational motion creates a shearing effect between the first row of teeth 16 and the second row of teeth 17, effectively crushing and breaking up large pieces of coked slag on the grate. The crushed ash falls from the gaps between the teeth into the ash channel below, which can be easily cleaned by simply opening the ash door 6, ensuring smooth primary air ventilation.

[0023] The inner wall of the furnace liner 5 is circumferentially arranged with multiple grooves 18 to increase the heating area and turbulent the flue gas. These grooves 18 play a crucial role in energy saving and environmental protection: on the one hand, they increase the heating area of ​​the inner wall of the furnace liner 5, improving the initial heat absorption efficiency; on the other hand, and more importantly, they turbulent the flue gas. When high-temperature flue gas flows through these grooves 18, the flow path is forced to change, generating eddies and turbulence, breaking the laminar boundary layer of the flue gas flow. This strong turbulence allows combustible gases and unburned particulate matter in the flue gas to mix more evenly with oxygen, prolonging their residence time in the high-temperature zone, thereby achieving more complete secondary combustion, reducing heat loss from incomplete chemical combustion and incomplete solid combustion, saving fuel and reducing pollutant emissions.

[0024] Inside the third flue gas chamber 4, corresponding to the interior of each of the third pass flue pipes 8, jet nozzles 19 are provided. The air inlet of each jet nozzle 19 extends to the outside of the furnace shell 1 through the air supply pipe 20 and is connected to the blower 22 through the one-way valve 21. The jet nozzles 19 are precisely aligned with the inlet of each third pass flue pipe 8, and the high-speed airflow is instantly injected into the flue pipe, generating a powerful purging force that loosens and peels off the ash adhering to the pipe wall, and discharges it upward from the exhaust port 11 with the airflow direction, thereby restoring the heat exchange efficiency of the flue pipe. This process does not require manual cleaning by stopping the machine.

[0025] It should be noted that this boiler is based on the structural improvement of existing small boilers, while its combustion principle remains unchanged. By optimizing the layout of the flue gas system, it has a compact structure, high thermal efficiency, convenient ash removal, energy saving and environmental protection, and effectively solves the problems of serious ash accumulation, difficult slag removal and low thermal efficiency of traditional small boilers.

[0026] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A three-pass reverse-fired boiler, characterized in that, include: A furnace shell (1) is provided with a first flue gas chamber (2) and a second flue gas chamber (3) arranged side by side at the top of the furnace shell (1), and a third flue gas chamber (4) is provided at the bottom of the furnace shell (1). Furnace chamber (5), the furnace chamber (5) is placed vertically below the first flue gas chamber (2), and the bottom of the furnace chamber (5) is provided with an ash channel extending horizontally to the outside of the furnace shell (1), the top of the ash channel is provided with a grate corresponding to the furnace chamber (5), and the outer end of the ash channel is provided with an ash door (6); The second pass flue (7) is distributed around the furnace chamber (5) and its two ends are connected to the first flue gas chamber (2) and the third flue gas chamber (4) respectively. The third return flue (8) is located below the second flue gas chamber (3) and its two ends are connected to the second flue gas chamber (3) and the third flue gas chamber (4) respectively. Panel (9), the panel (9) is disposed on the top of the furnace shell (1), and the panel (9) is provided with a furnace cover (10) corresponding to the first flue gas chamber (2) and a flue gas outlet (11) corresponding to the second flue gas chamber (3); The furnace shell (1) forms a cavity (12) with the first flue gas chamber (2), the second flue gas chamber (3), the third flue gas chamber (4) and the furnace liner (5), and the top and outer side walls of the furnace shell (1) are respectively provided with a water outlet pipe (13) and a water inlet pipe (14) that are connected to the cavity (12).

2. A three-pass reverse-fired boiler according to claim 1, characterized in that: The grate consists of a fixed grate and a rotating grate. The rotating grate includes a rotating shaft (15) that extends horizontally from the bottom of the furnace shell (5) to the outside of the furnace shell (1), and also includes a plurality of first teeth (16) located inside the furnace shell (5) and vertically connected to the rotating shaft (15). The plurality of first teeth (16) extend radially from the rotating shaft (15) and together form a support surface. The rotating shaft (15) is connected to a mechanism that drives its rotation. The fixed grate includes a plurality of second teeth (17) that are horizontally arranged at the bottom of the furnace shell (5). Each second tooth (17) is located between any two adjacent first teeth (16).

3. A three-pass reverse-fired boiler according to claim 1, characterized in that: The inner wall of the furnace (5) has multiple grooves (18) arranged circumferentially to increase the heating area and disturb the flue gas.

4. A three-pass reverse-fired boiler according to claim 1, characterized in that: The third flue gas chamber (4) is equipped with jet nozzles (19) corresponding to the interior of each of the third return flue pipes (8). The air inlet of each jet nozzle (19) extends to the outside of the furnace shell (1) through the gas supply pipe (20) and is connected to the blower (22) through the one-way valve (21).

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