Pressure-resistant condensing boiler

Abstract

The present invention relates to a pressure-resistant condensing boiler, comprising a pressure-resistant housing, a heat exchanger installed in the pressure-resistant housing, a combustion chamber connected to the heat exchanger, and a cooling pipe group fixed in the heat exchanger, wherein the pressure-resistant housing is provided with a combustor joint connected to the combustion chamber, a flue gas exhaust pipe connected to the heat exchanger, a heat exchange medium inlet and a heat exchange medium outlet, the heat exchange medium flows from bottom to top in the pressure-resistant housing and the cooling pipe group, and exchanges heat with the flue gas in the heat exchanger in a counterflow manner, the heat exchanger includes two or more cylindrical heat exchange chambers, adjacent heat exchange chambers communicate with each other through a transfer flue, adjacent transfer flue are installed in a manner to be spaced apart from each other, and the last-stage heat exchange chamber where the flue gas diffuses communicates with the flue gas exhaust pipe. This pressure-resistant condensing boiler may have a simple structure and a thermal efficiency higher than 100%.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This patent application was filed on July 16, 2021, and claims priority to Chinese patent application No. CN202110807836.2. The disclosure of the prior application is incorporated herein by reference in its entirety.

[0002] The present invention relates to the field of boiler technology, in particular to pressure condensing boilers. [Background technology]

[0003] Condensing boilers achieve the goal of improving the boiler's thermal efficiency by absorbing the sensible heat in high-temperature flue gas and the latent heat released by steam condensation. Their maximum thermal efficiency can reach 109%, which is 15-17% higher than that of a conventional gas furnace. Meanwhile, the exhaust gas temperature of condensing boilers is significantly reduced, resulting in ultra-low nitrogen oxide (NOx) emissions in the flue gas.

[0004] Condensing boilers have great application value due to their high efficiency and energy saving. However, conventional pressure condensing boilers have low heat exchange efficiency and high exhaust gas temperatures, so most pressure condensing boilers are installed as a set with a separate condensing heat exchanger outside the furnace, which makes the overall structure of the pressure condensing boiler very complicated and increases the manufacturing, installation and application costs. Summary of the Invention [Problem to be solved by the invention]

[0005] An embodiment of the present invention provides a pressure-resistant condensing boiler, which is based on the principles of counterflow heat exchange, enhanced flue gas side heat exchange, and enhanced convection heat exchange coefficient, and develops a condensing boiler suitable for pressure-resistant operation, improves its thermal efficiency to more than 100%, and significantly reduces the manufacturing, installation, and application costs of the pressure-resistant condensing boiler. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a pressure-resistant condensing boiler, which includes a pressure-resistant housing, a heat exchange furnace installed in the pressure-resistant housing, a combustion chamber communicating with the heat exchange furnace, and a cooling pipe group fixed in the heat exchange furnace; Here, the pressure housing is equipped with a combustor joint connected to the combustion chamber, a flue gas exhaust pipe connected to the heat exchange furnace pot, a heat exchange medium inlet and a heat exchange medium outlet, and the heat exchange medium flows from bottom to top within the pressure housing and the cooling pipe group, and exchanges heat with the flue gas in the heat exchange furnace pot in a counterflow manner. Note that the term combustor joint should be understood in a broad sense, and the combustion chamber joint is a connection structure between the combustion chamber and an external part, and any connection structure between the combustion chamber and an external part obtained by a person skilled in the art without any creative effort is within the scope of protection of the present application.

[0007] The heat exchange furnace includes two or more cylindrical heat exchange chambers, each with a flue gas inlet at the top and a flue gas outlet at the bottom. The flue gas inlet and flue gas outlet are spaced apart from each other, and adjacent heat exchange chambers communicate with each other via a conversion flue. The final heat exchange chamber, into which the flue gas diffuses, communicates with a flue gas outlet pipe.

[0008] In this solution, the high-temperature flue gas diffuses stepwise from top to bottom, and the heat exchange medium forms a counterflow heat exchange from bottom to top, with the lower-temperature heat exchange medium at the bottom lowering the discharge temperature of the flue gas and the upper-temperature flue gas raising the temperature of the discharged heat exchange medium. The pressure-resistant housing and cylindrical heat exchange furnace are used, making it suitable for pressure-resistant operation. The heat exchange medium (usually water) discharged from the pressure-resistant condensing boiler in this embodiment can be high- or low-temperature hot water or steam. In particular, each heat exchange chamber has a relatively independent heat exchange chamber, forcing the high-temperature flue gas to circulate through each heat exchange chamber, improving the heat exchange efficiency. The cylindrical heat exchange chambers also allow the boiler to operate under pressure. Compared with the prior art, which requires a separate condensing heat exchanger to be installed outside the furnace body as a set, the condensing boiler adopted in the embodiment of the present invention not only meets the requirements for single-stage energy efficiency of condensing boilers in "Energy Efficiency Limit Values ​​and Energy Efficiency Levels for Industrial Boilers (GB24500-2020)", but also does not require a separate condensing heat exchanger to be installed outside the furnace body as a set, and has a simple structure with low manufacturing, installation and application costs. The heat exchange furnace provided in this solution has high heat exchange efficiency, so it does not require a separate condensing heat exchanger to be installed outside the furnace body as a set.

[0009] Illustratively, the flue gas inlet or flue gas outlet is circular, arc-shaped, or near-elliptical, or the flue gas inlet or flue gas outlet includes a plurality of circular opening units, and the plurality of opening units are arranged in an arc-shaped or near-elliptical shape.

[0010] In some embodiments, one or more partition plates are installed between the pressure housing and the heat exchanger to surround the heat exchanger, which can prevent the heat exchange medium from flowing through the cooling pipes at a low or no flow rate due to resistance, and can also prevent the overheated heat exchange medium from flowing back to the lower low-temperature heat exchange medium area, which would increase the temperature of the heat exchange medium at the bottom and further increase the temperature of the flue gas in the flue gas discharge pipe.

[0011] For example, a partition plate is installed in each heat exchange chamber, which not only ensures that the heat exchange medium inside and outside the heat exchange chamber of each stage is in sufficient contact with the heat exchange medium, but also prevents the heat exchange medium with a higher temperature from flowing back into the area with a lower temperature heat exchange medium.

[0012] In some embodiments, the height of the heat exchange chambers in each stage decreases along the direction of flue gas diffusion.

[0013] In some embodiments, the heat exchange furnace includes a first heat exchange chamber, a second heat exchange chamber, and a third heat exchange chamber, which are sequentially connected to the combustion chamber; a first flue gas inlet is provided in the center of the upper end surface of the first heat exchange chamber, a first arc-shaped flue gas outlet is provided on the lower end surface along the peripheral wall, and a first cooling pipe group is arranged surrounding the first flue gas inlet; a second flue gas inlet corresponding to the first flue gas outlet is installed on the upper end surface of the second heat exchange chamber, a second flue gas outlet is installed on one side of the lower end surface away from the second flue gas inlet, and a second cooling pipe group is installed between the second flue gas inlet and the second flue gas outlet; A third flue gas inlet corresponding to the second flue gas outlet is provided on the upper end surface of the third heat exchange chamber, a third flue gas outlet is provided on one side of the lower end surface away from the third flue gas inlet, and a third group of cooling pipes is arranged between the third flue gas inlet and the third flue gas outlet.

[0014] In the above solution, the hot flue gas flows sequentially through the first heat exchange chamber, the second heat exchange chamber, and the third heat exchange chamber in a folded manner. In the first heat exchange chamber, the hot flue gas spreads radially from the first flue gas inlet, flushing laterally through the first cooling pipe group surrounding the first flue gas inlet. Through the first flue gas outlet, the hot flue gas enters the second heat exchange chamber. The second flue gas outlets are located on the other side of the second flue gas inlet in a mutually spaced apart manner, so that the flue gas fully exchanges heat with the second cooling pipe group in a transverse flushing manner. The same principle applies to the third heat exchange chamber.

[0015] In some embodiments, the heat exchange furnace further includes a fourth heat exchange chamber communicating with the third heat exchange chamber, a fourth flue gas inlet corresponding to the third flue gas outlet is installed on the upper end surface of the fourth heat exchange chamber, a fourth flue gas outlet communicating with the flue gas outlet pipe is installed on the side wall, and multiple sets of fourth cooling pipes are arranged between the fourth flue gas inlet and the fourth flue gas outlet. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing the external structure of a pressure-resistant condensing boiler according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view of the structure of FIG. [Figure 3] 1 is a schematic diagram of the three-dimensional structure of a heat exchange furnace according to an embodiment of the present invention; [Figure 4] 4 is a schematic diagram 1 of the exploded structure of FIG. 3. [Figure 5] 4 is a schematic diagram 2 of the exploded structure of FIG. 3. [Figure 6] FIG. 10 is a structural schematic diagram of a first flue gas outlet in another embodiment. [Figure 7] FIG. 10 is a structural schematic diagram of a second flue gas outlet in another embodiment. [Explanation of symbols]

[0017] 10 - pressure-resistant housing, 11 - heat exchange medium inlet, 12 - heat exchange medium outlet, 13 - partition plate, 20—heat exchange furnace kettle; 201—first conversion flue; 202—second conversion flue; 203—third conversion flue; 21 - first heat exchange chamber; 211 - first cooling tube group; 212 - first flue gas inlet; 213 - first flue gas outlet; 214 - first lower tube plate; 22—second heat exchange chamber; 221—second cooling tube group; 223—second flue gas outlet; 224—third lower tube plate; 23—third heat exchange chamber; 231—third cooling tube group; 233—third flue gas outlet; 24—fourth heat exchange chamber; 241—fourth cooling tube group; 243—fourth flue gas outlet; 30 - combustion chamber, 31 - combustor fitting, 32 - flue gas exhaust pipe. DETAILED DESCRIPTION OF THE INVENTION

[0018] In order to make the technical problems, technical solutions and beneficial effects of the present invention clearer, the present invention will be described in more detail below in conjunction with the drawings and examples. It should be understood that the specific examples described herein are only used to interpret the present invention, and are not intended to limit the present invention.

[0019] Both pressure-resistant condensing boilers and atmospheric-pressure condensing boilers are types of boiler products. Atmospheric-pressure boilers have a rated working pressure of 0 (gauge pressure) and an outlet medium temperature of no more than 90°C. Pressure-resistant boilers have an operating pressure of ≥ 0.1 MPa and an outlet medium temperature of over 100°C. Pressure-resistant boilers can adjust the water temperature. They can provide not only high- and low-temperature hot water, but also high-temperature steam. Furthermore, pressure-resistant boilers can be used directly in pressurized operating environments. Therefore, pressure-resistant boilers have a wider range of applications.

[0020] The applicant has previously developed an atmospheric condensing boiler, which uses a flue gas baffle to separate a rectangular heat exchange furnace into a continuous flue gas passage with at least one spiral structure, but this structure cannot be applied to a pressure boiler. Therefore, the present invention provides a pressure condensing boiler that can be applied to a wider range of cases.

[0021] The present invention will now be described in more detail in conjunction with the drawings and specific embodiments.

[0022] 1 and 2, a pressure-resistant condensing boiler according to an embodiment of the present invention includes a pressure housing 10, a heat exchanger 20 installed within the pressure housing 10, a combustion chamber 30 connected to the heat exchanger 20, and a group of cooling pipes fixed within the heat exchanger 20. As shown in FIG. 1, the pressure housing 10 is substantially cylindrical, with an elliptical head formed by integral upper and lower ends. A combustor coupling 31 for connecting the combustion chamber 30 is installed at the top of the pressure housing 10, and a flue gas discharge pipe 32 connected to the heat exchanger 20 is installed at the bottom of the pressure housing 10. The closed end of the combustion chamber 30 has a smooth tip, and the other end is an open end, which is connected to the combustor coupling 31 with a smooth transition. Premixed combustible gas is fully combusted within the combustion chamber 30, and high-temperature flue gas diffuses from top to bottom through the heat exchanger 20 into the flue gas discharge pipe 32. Furthermore, a heat exchange medium inlet 11 communicating with the heat exchange medium is provided at the bottom of the pressure housing 10, and a heat exchange medium outlet 12 is provided at the top of the pressure housing 10. A relatively low-temperature heat exchange medium enters through the heat exchange medium inlet 11 and then flows from bottom to top within the pressure housing 10 and through the cooling pipe group. As the heat exchange medium flows from bottom to top, it exchanges heat with the high-temperature flue gas in the heat exchange furnace 20 in a counterflow manner.

[0023] In this embodiment, the heat exchange furnace 20 includes two or more cylindrical heat exchange chambers. Adjacent heat exchange chambers are connected via a transfer flue. The adjacent transfer flue channels are spaced apart from each other. At the final stage of flue gas diffusion, the heat exchange chambers are connected to a flue gas exhaust pipe 32. The cylindrical heat exchange chambers are pressure-resistant, and a heat exchange space suitable for the flow of heat exchange medium is formed between the heat exchange chambers and the pressure-resistant housing 10. Each stage of the heat exchange chambers has relatively independent heat exchange chambers. Adjacent heat exchange chambers are connected to form a continuous flue via a transfer flue. This increases the return flow of flue gas, favoring efficient heat exchange. This improves the outlet temperature of the heat exchange medium and reduces the outlet temperature of the flue gas, thereby improving thermal efficiency.

[0024] In the above solution, two or more stages of heat exchange chambers are installed, for example, two stages of heat exchange chambers, three stages of heat exchange chambers, four stages of heat exchange chambers or more are installed, the flue gas inlet and flue gas outlet of each stage of heat exchange chamber are installed in a manner that is separated from each other, the flue gas sufficiently flushes the cooling pipe group in each stage of heat exchange chamber to achieve effective heat exchange, the flue gas temperature in the heat exchange chamber is reduced stepwise, and the flue gas temperature in the last stage of heat exchange chamber is the lowest. In this application, there is no limitation on the number of stages installed in the heat exchange chamber.

[0025] The flue gas inlet or flue gas outlet of each heat exchange chamber has a smooth transition to the corresponding heat exchange chamber, and the side walls of the transition flue communicating with the corresponding flue gas inlet and flue gas outlet also have a smooth transition. Each heat exchange chamber has a cylindrical side wall and an upper tube plate and a lower tube plate (not numbered in FIGS. 1 and 2) hermetically connected to the side wall. The upper tube plate has a flue gas inlet, and the lower tube plate has a flue gas outlet. The upper and lower tube plates are further secured to each other by welding or other means. The cooling tube group is installed upright in the heat exchange chamber, with both ends protruding from the corresponding upper and lower tube plates. The cooling tube group's pipe holes communicate with the interior space of the pressure housing 10 but not with the interior space of the heat exchange furnace kettle 20. The heat exchange medium (usually water) flows into the cooling tube group to exchange heat with the high-temperature flue gas in the heat exchange chamber. The heat exchange medium then exits the cooling tube group and mixes with the heat exchange medium in the pressure-resistant housing 10. The flue gas inlet and flue gas outlet have a smooth transitional structure, such as a circle (the first flue gas inlet 212 shown in FIG. 4), an arc (the first flue gas outlet 213 shown in FIG. 5), or a near-ellipse (the second flue gas outlet 223 or the third flue gas outlet 233 shown in FIG. 5). The smooth transitional structure is suitable for pressure resistance. The cross section of the conversion flue matches the shape of the corresponding flue gas inlet or flue gas outlet, making it suitable for pressure resistance. The shape of the flue gas inlet and flue gas outlet may also be composed of multiple circular opening units, which may be arranged in an arc or near-ellipse, as shown in FIGS. 6 and 7.

[0026] To improve the heat exchange efficiency of the pressure condensing boiler, one or more partition plates 13 are installed inside the pressure housing 10. As shown in FIG. 2, the partition plates 13 are installed around the heat exchange furnace kettle 20 and are located between the pressure housing 10 and the heat exchange furnace kettle 20. One partition plate 13 can be installed above the final heat exchange chamber to prevent the reflux of relatively high-temperature heat exchange medium, which would increase the temperature of the heat exchange medium in the lower part of the pressure housing 10, reduce the heat exchange efficiency of the final heat exchange chamber, and further increase the temperature of the flue gas.

[0027] In some embodiments, a partition plate 13 is installed in each heat exchange chamber. The heat exchange medium entering through the heat exchange medium inlet 11 flows through the cooling pipe group into the space between the heat exchange furnace kettle 20 and the pressure-resistant housing 10. The partition plate 13 prevents the heat exchange medium in the upper stage from flowing back into the relatively low-temperature heat exchange medium region, thereby effectively improving the efficiency of heat exchange. Naturally, the partition plate 13 may completely close the gap between the pressure-resistant housing 10 and the heat exchange furnace pot 20, or it may not completely close the gap between the pressure-resistant housing 10 and the heat exchange furnace pot 20. If the partition plate 13 completely closes the gap, the gap is divided by the partition plate 13 into adjacent spaces that are not connected to each other, and at this time, the heat exchange medium cannot flow through the gap and can only flow through the cooling pipe group. If the partition plate 13 does not completely close the gap, the gap is divided by the partition plate 13 into adjacent spaces that are connected to each other, and at this time, the heat exchange medium can flow through the gap and the cooling pipe group at the same time. Multiple partition plates 13 may be installed, but a closed space through which the heat exchange medium cannot flow cannot be formed between adjacent partition plates 13.

[0028] The height of the heat exchange chambers of each stage may be the same or different. In some embodiments, the height of the heat exchange chambers of each stage decreases sequentially along the direction of diffusion of the flue gas to adjust the flow rate of the flue gas through the heat exchange chambers of each stage and make the flow rate of the flue gas uniform. Generally, when the flue gas flows from top to bottom, the temperature of the flue gas in the upper heat exchange chamber is high and the height of the heat exchange chamber is large, and the temperature of the flue gas in the last heat exchange chamber is low and the height of the heat exchange chamber is small.

[0029] 2 to 5, a heat exchange furnace 20 is provided with three stages of heat exchange chambers, including a first heat exchange chamber 21, a second heat exchange chamber 22, and a third heat exchange chamber 23, which are successively connected to the combustion chamber 30. A first flue gas inlet 212 is provided in the center of the upper end surface of the first heat exchange chamber 21, a first arc-shaped flue gas outlet 213 is provided on the lower end surface of the first heat exchange chamber 21 and extends along the peripheral wall, and a first cooling pipe group 211 is arranged in the first heat exchange chamber 21 surrounding the first flue gas inlet 212. A second flue gas inlet corresponding to the first flue gas outlet 213 is provided on the upper end surface of the second heat exchange chamber 22, a second flue gas outlet 223 is provided on one side of the lower end surface of the second heat exchange chamber 22 away from the second flue gas inlet, and multiple sets of second cooling pipe groups 221 arranged in an arc shape are provided between the second flue gas inlet and the second flue gas outlet 223. A third flue gas inlet corresponding to the second flue gas outlet 223 is provided on the upper end surface of the third heat exchange chamber 23, and a third flue gas outlet 233 is provided on one side of the lower end surface of the third heat exchange chamber 23 away from the third flue gas inlet, and multiple sets of third cooling pipe groups 231 are arranged between the third flue gas inlet and the third flue gas outlet 233. The second flue gas inlet matches the shape of the first flue gas outlet 213, and the two are connected via the first conversion flue 201; similarly, the third flue gas inlet matches the shape of the second flue gas outlet 223, and the two are connected via the second conversion flue 202.

[0030] It should be noted that the terms "first" and "second" are for descriptive purposes only and cannot be understood as indicating or implying the relative importance or number of the indicated technical features.

[0031] The high-temperature flue gas discharged from the combustion chamber 30 diffuses radially into the first heat exchange chamber 21, and is discharged from the first heat exchange chamber 21 through the first flue gas outlet 213 at the bottom of the first heat exchange chamber 21 into the second heat exchange chamber 22. After entering the second heat exchange chamber 22 through the second flue gas inlet, the flue gas diffuses in an enveloping manner, flushing laterally through the second cooling pipe group 221, then collecting at the second flue gas outlet 223, and finally diffusing through the second conversion flue 202 into the third heat exchange chamber 23. The flue gas flushes laterally through the third cooling pipe group 231 within the third heat exchange chamber 23, and the third flue gas inlet and the third flue gas outlet 233 are spaced apart from each other, thereby lengthening the flue gas diffusion path and improving heat exchange efficiency.

[0032] 2 to 5, based on the requirements of heat exchange efficiency and flue gas temperature, in another embodiment, the heat exchanger kettle 20 further includes a fourth heat exchanger chamber 24 communicating with the third heat exchanger chamber 23. A fourth flue gas inlet corresponding to the third flue gas outlet 233 is provided on the upper end surface of the fourth heat exchanger chamber 24, and a fourth flue gas outlet 243 communicating with the flue gas outlet pipe 32 is provided on the side wall of the fourth heat exchanger chamber 24. A plurality of fourth cooling pipe groups 241 are arranged between the fourth flue gas inlet and the fourth flue gas outlet 243. Of course, to improve the heat exchange efficiency, the heat exchanger kettle 20 may further include a fifth heat exchanger chamber, a sixth heat exchanger chamber, etc.

[0033] The installation of the heat exchange chambers will be explained below using a four-stage heat exchange chamber as an example.

[0034] As shown in Figure 4, the first flue gas inlet 212 is circular, and both ends of the first cooling pipe group 211 penetrate the upper and lower tube plates of the first heat exchange chamber 21. The first cooling pipe group 211 is arranged circumferentially around the first flue gas inlet 212, with two circumferential rows, and the inner and outer cooling pipes are offset circumferentially. The first flue gas outlet 213 has an overall arc shape and fits into the outer wall of the first heat exchange chamber 21. The first flue gas outlet 213 has a smooth transition structure. Hot flue gas enters the first heat exchange chamber 21 through the first flue gas inlet 212 and radially flushes the first cooling pipe group 211 arranged around the first flue gas inlet 212, achieving sufficient heat exchange.

[0035] The first cooling pipe group 211 may be installed in three or four or more turns, but the present application is not limited to this.

[0036] In another embodiment, the first flue gas discharge outlet 213 may further be composed of a plurality of circular opening units, which are arranged in an arc shape as shown in FIG. 6, and on the first lower tube plate 214, the arrangement locus of the plurality of opening units matches the outer edge of the first lower tube plate 214.

[0037] The second flue gas inlet matches the shape of the first flue gas outlet 213. The cross-sectional shape of the first conversion flue 201 matches the shape of the first flue gas outlet 213, and the connecting surfaces transition smoothly. The second flue gas outlet 223 is circular or near-elliptical. The second flue gas outlet 223 is located on the lower end surface of the second heat exchange chamber 22, on one side away from the second flue gas inlet. The second cooling pipe group 221 has multiple sets and is arranged in an arc. The opening direction of the arc in which the second cooling pipe group 221 is arranged is the same as the opening direction of the arc in which the second flue gas inlet is arranged. As shown in FIG. 4 , the second cooling pipe group 221 is arranged similarly to a shield, where the protective surface of the shield faces the second flue gas inlet, thus promoting sufficient contact between the second cooling pipe group 221 and the diffused flue gas.

[0038] The second flue gas discharge outlet 223 may further be composed of a plurality of circular opening units, which are arranged in a near-elliptical shape, as shown in FIG. 7 (the cooling pipe group is not shown in the figure), and the second flue gas discharge outlet 223 includes one relatively large circular opening unit and two relatively small circular opening units, where the one relatively large opening unit and the two relatively small opening units are combined in a near-elliptical shape.

[0039] The shape of the third flue gas inlet matches the shape of the second flue gas outlet 223, and the third flue gas outlet 233 is also nearly elliptical. A third group of cooling pipes 231 is installed between the third flue gas inlet and the third flue gas outlet 233, and the third group of cooling pipes 231 has multiple pipes and is arranged in a hyperbolic shape to match the third flue gas outlet 233.

[0040] The fourth flue gas inlet has the same structure as the third flue gas inlet. A fourth flue gas outlet 243 is opened in the side wall of the fourth heat exchange chamber 24, and the fourth flue gas outlet 243 communicates with the flue gas exhaust pipe 32.

[0041] A condensate discharge pipe is connected to the bottom of the heat exchange furnace kettle 20 and is used to discharge condensate. The condensate discharge pipe extends through the pressure housing 10 to the outside of the pressure housing 10, thereby allowing condensate to be discharged from the furnace body.

[0042] To increase the heat exchange area, heat exchange fins (not shown) may be installed on the outer walls of the second cooling pipe group 221, the third cooling pipe group 231, and the fourth cooling pipe group 241. The heat exchange fins are distributed spirally along the axial direction of the cooling pipes.

[0043] The pressure condensing boiler provided in this application is tested in accordance with GB / T10180-2017 "Industrial Boiler Thermal Engineering Test Procedure." When the pressure condensing boiler is operated at full load and the return water temperature is 60°C, the flue gas outlet temperature is 61°C and the thermal efficiency (calculated based on the lower heating value) is 100%. When the pressure condensing boiler is operated at full load and the return water temperature is 30°C, the flue gas outlet temperature is 41°C and the thermal efficiency (calculated based on the lower heating value) is 105%. When the pressure condensing boiler is operated at 30% load and the return water temperature is 30°C, the flue gas outlet temperature is 35°C and the thermal efficiency (calculated based on the lower heating value) is 108%. When the pressure condensing boiler is operated at full load and steam is generated, the flue gas outlet temperature is 52°C and the thermal efficiency (calculated based on the lower heating value) is 103%.

[0044] The above description is merely a preferred embodiment of the present invention, and does not limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application should be included within the protection scope of the present application.

Claims

1. A pressure-resistant condensing boiler including a pressure-resistant housing (10), a heat exchange furnace (20) installed in the pressure-resistant housing (10), and a combustion chamber (30) communicating with the heat exchange furnace (20), The pressure-resistant housing (10) is provided with a combustor joint (31) connected to the combustion chamber (30), a flue gas exhaust pipe (32) communicating with the heat exchange furnace (20), a heat exchange medium inlet (11), and a heat exchange medium outlet (12), where the heat exchange medium flows from bottom to top within the pressure-resistant housing (10) and the cooling pipe group, and exchanges heat with the flue gas in the heat exchange furnace (20) in a counterflow manner. The heat exchange furnace (20) includes a first heat exchange chamber (21), a second heat exchange chamber (22), and a third heat exchange chamber (23) sequentially communicating with the combustion chamber (30), and the first heat exchange chamber (21), the second heat exchange chamber (22), and the third heat exchange chamber (23) each include a cylindrical side wall and an upper tube plate and a lower tube plate hermetically connected to the side wall, the first heat exchange chamber (21), the second heat exchange chamber (22), and the third heat exchange chamber (23) are provided with cooling pipes, a flue gas inlet is provided in the upper tube plate, and a flue gas discharge port is provided in the lower tube plate, the flue gas inlet and the flue gas discharge port are provided apart from each other, adjacent heat exchange chambers communicate with each other via a conversion flue, and the heat exchange chamber in the final stage, into which the flue gas diffuses, communicates with the flue gas discharge pipe (32), a first flue gas inlet (212) is provided in the middle of an upper tube plate of the first heat exchange chamber (21), the first flue gas inlet (212) is circular, a first cooling pipe group (211) provided in the first heat exchange chamber (21) is arranged circumferentially around the first flue gas inlet (212), a first flue gas discharge port (213) is provided on a lower tube plate of the first heat exchange chamber (21) at a location close to a peripheral wall, the first flue gas discharge port (213) is arc-shaped, or the first flue gas discharge port (213) includes a plurality of circular second opening units, and the plurality of second opening units are arranged in an arc shape that fits the peripheral wall of the first heat exchange chamber (21); A second group of cooling pipes (221) arranged in an arc shape is installed in the second heat exchange chamber (22), a third flue gas inlet having a circular or elliptical shape is provided on the upper tube plate of the third heat exchange chamber (23), and a third cooling tube group installed in the third heat exchange chamber (23) is arranged in a hyperbolic shape to fit the third flue gas inlet.

2. 2. The pressure-resistant condensing boiler according to claim 1, wherein the flue gas inlet of the second heat exchange chamber (22), the flue gas outlet of the second heat exchange chamber (22), or the flue gas outlet of the third heat exchange chamber (23) is circular, arc-shaped, or near-elliptical, or the flue gas inlet of the second heat exchange chamber (22), the flue gas outlet of the second heat exchange chamber (22), or the flue gas outlet of the third heat exchange chamber (23) includes a plurality of circular first opening units, and the plurality of first opening units are arranged in an arc-shaped or near-elliptical shape.

3. 2. The pressure-resistant condensing boiler according to claim 1, wherein one or more partition plates (13) are installed between the pressure-resistant housing (10) and the heat exchanger kettle (20), surrounding the heat exchanger kettle (20).

4. 4. The pressure-resistant condensing boiler according to claim 3, wherein a partition plate (13) is provided in each of the heat exchange chambers of each stage.

5. 2. The pressure-resistant condensing boiler according to claim 1, wherein the heights of the first heat exchange chamber (21), the second heat exchange chamber (22) and the third heat exchange chamber (23) decrease successively.

6. a second flue gas inlet corresponding to the first flue gas outlet (213) is provided on an upper tube plate of the second heat exchange chamber (22); a second flue gas outlet (223) is provided on one side of a lower tube plate of the second heat exchange chamber (22) away from the second flue gas inlet; and the second cooling pipe group (221) is provided between the second flue gas inlet and the second flue gas outlet (223); 2. The pressure-resistant condensing boiler according to claim 1, wherein the third flue gas inlet and the second flue gas discharge port (223) are installed corresponding to each other, a third flue gas discharge port (233) is installed on one side of the lower tube plate of the third heat exchange chamber (23) away from the third flue gas inlet, and the third cooling pipe group (231) is arranged between the third flue gas inlet and the third flue gas discharge port (233).

7. 7. The pressure-resistant condensing boiler according to claim 6, wherein the heat exchange furnace (20) further includes a fourth heat exchange chamber (24) communicating with the third heat exchange chamber (23), a fourth flue gas inlet corresponding to the third flue gas outlet (233) is provided on an upper tube plate of the fourth heat exchange chamber (24), a fourth flue gas outlet (243) communicating with the flue gas outlet pipe (32) is provided on a side wall of the fourth heat exchange chamber (24), and a fourth group of cooling pipes (241) are arranged between the fourth flue gas inlet and the fourth flue gas outlet (243).

8. 8. The pressure-resistant condensing boiler according to claim 7, wherein the second flue gas inlet corresponds to the position of the first flue gas outlet (213), the second flue gas inlet is adapted to the shape of the first flue gas outlet (213), and the second flue gas outlet (223) is circular or near-elliptical, or the second flue gas outlet (223) includes a plurality of circular third opening units, and the plurality of third opening units are arranged in a near-elliptical shape.

9. the fourth flue gas inlet is approximately elliptical, or the fourth flue gas inlet includes a plurality of fourth opening units, and the plurality of fourth opening units are arranged in a approximately elliptical shape; 9. The pressure-resistant condensing boiler according to claim 8, wherein the fourth cooling pipe group (241) has a plurality of cooling pipes and is arranged in a hyperbolic shape to fit the corresponding flue gas inlets.

10. The pressure-resistant condensing boiler according to claim 7, characterized in that heat exchange fins are installed on the outer walls of the second cooling pipe group (221), the third cooling pipe group (231), and the fourth cooling pipe group (241).

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