Hot water boiler capable of maintaining heat load balance

Abstract

The invention relates to the technical field of hot water boilers, and discloses a hot water boiler capable of maintaining heat load balance, which comprises a boiler main body, a burner is mounted on the surface of the boiler main body, a fire tube is mounted in the boiler main body, tube plates are mounted on two sides of the fire tube, and a plurality of smoke tubes are fixedly connected between the tube plates on two sides. A first heat exchange layer is arranged in the fire tube, and a preheating mechanism is installed between an interlayer between the first heat exchange layer and the fire tube and the combustor. Efficient gradient utilization and precise regulation and control of heat are achieved through the collaborative process of preheating air through flames, heating the chimney through the flames, exchanging heat between smoke and a phase change medium and heating water through the phase change medium; in heat load fluctuation scenes such as oil exploitation associated gas recovery heating, working condition media absorb flue gas waste heat for phase change heat storage and release heat at low ebb to maintain the water temperature stable, it is ensured that the temperature fluctuation of hot water output by a boiler is small, and the requirement for stable heat energy supply in the oil processing flow is met.

Description

Technical Field

[0001] This invention relates to the field of hot water boiler technology, specifically a hot water boiler capable of maintaining heat load balance. Background Technology

[0002] In oil extraction and processing scenarios, hot water boilers are core heat energy conversion equipment, and defects in their combustion heat exchange technology have a significant impact on production.

[0003] Existing boilers rely on high-efficiency burners to mix fuels (natural gas, diesel, biomass, etc.) with air for combustion, and use furnace radiation and convection tube bundle heat exchange to achieve heat energy conversion. However, this conflicts with the precise control of heat energy required for oil extraction and processing.

[0004] Combustion produces high-temperature flue gas of 800-1000℃. Due to the lack of an active flow field control mechanism, it relies on natural diffusion and is concentrated at the burner end due to inertia and furnace space limitations.

[0005] In processes such as associated gas recovery and heating in oil extraction and waste heat utilization in refining and chemical plants, the metal of the boiler heating surface (such as heat-resistant alloy steel) is subjected to uneven thermal stress due to local high temperature erosion. This is analogous to the fatigue damage of oil pipes under high pressure and variable temperature conditions. The pipe wall is prone to creep, bulging, or even pipe rupture, which directly affects the continuous supply of heat energy for oil processing.

[0006] High-temperature zones cause flue gas ash to melt and deposit into a dense coke layer, hindering heat transfer. Similar to scale buildup in oil distillation towers, this reduces heat transfer efficiency, increasing energy consumption. Furthermore, the slow oxidation of the ash layer makes heat dissipation difficult, posing a risk of secondary combustion in the flue. In oil processing plant areas, this can easily amplify the hazards of safety accidents by combining with flammable and explosive media.

[0007] Furthermore, existing burners use a fixed air-fuel ratio design. The associated gas from petroleum has a complex composition and large fluctuations in calorific value. The fixed ratio leads to incomplete combustion, similar to the reaction imbalance caused by fluctuations in feed properties in catalytic cracking units of oil refineries. This results in reduced boiler thermal efficiency and excessive emissions of unburned materials. These defects directly restrict energy utilization efficiency and production safety in oil extraction and processing.

[0008] Therefore, this invention proposes a hot water boiler that can maintain heat load balance. Summary of the Invention

[0009] The purpose of this invention is to provide a hot water boiler that can maintain heat load balance in order to solve the problems mentioned in the background art.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a hot water boiler capable of maintaining heat load balance, comprising a boiler body, a burner mounted on the surface of the boiler body, fire tubes mounted inside the boiler body, tube sheets mounted on both sides of the fire tubes, and a plurality of chimneys fixedly connected between the tube sheets on both sides, a heat exchange layer I is provided inside the fire tubes, a preheating mechanism is installed between the heat exchange layer I and the fire tubes and the burner, a heat exchange layer II is provided inside the chimneys, and a working medium is stored between the heat exchange layer II and the chimneys, wherein when the burner is working, the flame is emitted from the burner output end. The air is ejected and extends to the far end of the fire tube. The preheating mechanism delivers the air preheated by the flame to the combustion end to aid combustion. The flame is deflected back by the tube sheet to form a return flame, creating a high-temperature flue gas zone near the burner output end. The high-temperature flue gas flows on the surface of the second heat exchange layer and undergoes convective heat exchange with the water between the chimney, the boiler body, and the fire tube. At the same time, the heat is transferred to the working medium through the thin wall of the second heat exchange layer, causing it to absorb heat and undergo a phase change to store thermal energy. The working medium stores heat during peak heat load and releases heat during troughs. The phase change regulates the chimney wall temperature, ensuring a stable water temperature inside the boiler body and achieving a dynamic balance between quadruple heat exchange and heat load.

[0011] Preferably, the outer surface of the chimney is surrounded and fixedly connected with several sets of fins. Each set of fins is distributed at intervals along the axial direction of the chimney and is perpendicular to the outer surface of the chimney. By increasing the contact area between the chimney and the boiler body and fire tubes, the convective heat exchange efficiency between flue gas and water is enhanced, thereby improving the first-stage heat exchange effect.

[0012] Preferably, the working medium is an energy storage material with reversible phase change characteristics, and the phase change is either a solid-solid phase change or a solid-liquid phase change.

[0013] Preferably, the preheating mechanism includes two symmetrically arranged connecting pipes, which are respectively fixedly connected to the inner sidewall of the first heat exchange layer and extend to the interlayer space between the fire tube and the first heat exchange layer.

[0014] Preferably, the preheating mechanism further includes a fan, which is connected to a connecting pipe away from the burner output direction, and preheats by driving air to flow through the annular channel between the heat exchange layer and the fire tube.

[0015] Preferably, the connecting pipe near the burner is sealed to the air inlet of the burner via an external pipe.

[0016] Preferably, a flue pipe is fixedly connected to the surface of the boiler body on the side away from the burner.

[0017] Preferably, a cold water inlet and a hot water outlet are respectively installed on the top of the boiler body, and both the cold water inlet and the hot water outlet are connected to the interlayer between the boiler body and the fire tube.

[0018] Preferably, an expansion valve is installed on the top of the boiler body, which communicates with the interlayer between the boiler body and the fire tube.

[0019] Preferably, the enclosed space formed between the boiler body and the fire tubes, with both ends blocked by tube sheets, is a water heating chamber, and both the cold water inlet and the hot water outlet are connected to this water heating chamber.

[0020] Preferably, the working medium is encapsulated in the cavity between the chimney and the second heat exchange layer.

[0021] Compared with the prior art, the beneficial effects of the present invention are: 1. Through the coordinated process of preheating air with flame, heating the chimney with flame, exchanging heat between flue gas and phase change medium, and heating water with phase change medium, efficient and precise utilization and control of heat are achieved. In scenarios with fluctuating heat loads such as associated gas recovery and heating in oil extraction, the working medium absorbs the waste heat of flue gas and stores it through phase change. During low periods, it releases heat to maintain stable water temperature, ensuring that the temperature fluctuation of the boiler output hot water is small. This meets the demand for stable heat supply in the oil processing process and avoids the continuity of oil extraction and processing due to temperature fluctuations.

[0022] 2. The air preheating mechanism recovers the waste heat of the flame to heat the combustion air, forming a highly efficient "flame-air" heat exchange closed loop. After preheating, the air enters the burner, improving fuel combustion efficiency, making the flame more stable and releasing heat more fully. In view of the complex composition and large fluctuation of calorific value of associated petroleum gas, stable combustion can reduce pollutants caused by incomplete combustion, reduce the impact on the environment of the oil processing plant area, and at the same time improve thermal efficiency and reduce fuel consumption, which meets the needs of cost reduction and efficiency improvement in oil extraction and processing.

[0023] 3. The combination of the finned structure on the outer surface of the chimney and the internal phase change medium solves the problem of uneven heat exchange of flue gas in traditional boilers. The fins increase the contact area between the chimney and water to enhance convective heat transfer, and the phase change medium dynamically regulates the chimney wall temperature to avoid local overheating or undercooling. In oil extraction and processing, it can effectively prevent overheating of the heating surface, thermal fatigue of metal materials, and coking and ash accumulation caused by the accumulation of high-temperature flue gas, ensuring the long-term stable operation of the boiler and maintaining the continuity of heat energy supply for oil extraction and processing.

[0024] 4. The scientific layout of the fire tubes, chimney, and water heating chamber optimizes the heat transfer path, enabling efficient transfer of flue gas heat to water through multiple pathways and reducing heat loss. Compared to existing technologies where a large amount of flue gas heat is lost with exhaust, this invention improves heat utilization efficiency, reduces boiler operating costs in oil extraction and processing, and enhances the economics of energy utilization.

[0025] 5. The phase change energy storage characteristics of the working medium endow the boiler with the ability to intelligently regulate the heat load. It can automatically store or release heat according to the changes in water temperature, realize the dynamic balance of heat load, adapt to the rapid changes in the heating demand of oil extraction and processing, avoid problems such as unstable heating temperature and high energy consumption, meet the energy-saving and high-efficiency heating requirements of modern oil extraction and processing, provide more reliable and efficient thermal energy support for oil extraction and processing scenarios, optimize the combustion heat exchange mechanism from multiple dimensions, solve the common pain points of thermal energy systems in this field, and provide underlying logical support for subsequent oil extraction and processing. Attached Figure Description

[0026] Figure 1 This is a frontal perspective three-dimensional schematic diagram of the main structure of the present invention.

[0027] Figure 2 This is a rear-view perspective view of the main structure of the present invention.

[0028] Figure 3 This is a three-dimensional cross-sectional view of the main structure of the present invention.

[0029] Figure 4 This is a three-dimensional schematic diagram of the internal structure of the boiler body of the present invention.

[0030] Figure 5 For the present invention Figure 3 Enlarged 3D structural diagram at point A.

[0031] Figure 6 For the present invention Figure 3 Enlarged 3D structural diagram at point B.

[0032] Figure 7 This is a three-dimensional sectional view of the main structure of the present invention from another angle.

[0033] Figure 8 For the present invention Figure 7 Enlarged 3D structural diagram at point C.

[0034] Figure 9 This is a three-dimensional schematic diagram of the movement path of the burner output flame of the present invention.

[0035] Figure 10 This is a three-dimensional schematic diagram of the high-temperature flue gas flow path in this invention.

[0036] In the diagram: 1. Boiler body; 2. Burner; 3. Fire tube; 31. Heat exchange layer one; 4. Tube sheet; 5. Chimney; 52. Heat exchange layer two; 53. Operating medium; 51. Fins; 6. Flue pipe; 7. Cold water inlet; 8. Hot water outlet; 9. Preheating mechanism; 91. Connecting pipe; 92. Fan. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0038] It should be noted that burner 2 only provides combustion function, fan 92 only provides input and output of external air function, and external scale inhibitor only provides scale reduction function. The working principle and specific structure of the above structure are existing technologies. Therefore, given the universality of the above structure, its specific principle will not be described in detail below.

[0039] Please see Figures 1 to 10 This invention provides an embodiment of a hot water boiler capable of maintaining heat load balance, comprising a boiler body 1, a burner 2 mounted on the surface of the boiler body 1, fire tubes 3 mounted inside the boiler body 1, tube sheets 4 mounted on both sides of the fire tubes 3, and a plurality of chimneys 5 fixedly connected between the tube sheets 4 on both sides. A heat exchange layer 31 is provided inside the fire tubes 3, and a preheating mechanism 9 is installed between the heat exchange layer 31 and the fire tubes 3 and the burner 2. A second heat exchange layer 52 is provided inside the chimneys 5, and a working medium 53 is stored between the second heat exchange layer 52 and the chimneys 5. When the burner 2 is working, flames are ejected from the output end of the burner 2, directed towards the fire... The tube 3 extends to the far end, and the preheating mechanism 9 delivers the air preheated by the flame to the combustion end for combustion assistance. The flame is deflected back by the tube sheet 4 to form a return flame, forming a high-temperature flue gas zone near the output end of the burner 2. The high-temperature flue gas flows on the surface of the heat exchange layer 52 and undergoes convective heat exchange with the water between the boiler body 1 and the fire tube 3 through the chimney 5. At the same time, the heat is transferred to the working medium 53 through the thin wall of the heat exchange layer 52, causing it to absorb heat and undergo a phase change to store thermal energy. The working medium 53 stores heat during peak heat load and releases heat during trough. By adjusting the wall temperature of the chimney 5 through phase change, the water temperature inside the boiler body 1 is kept stable, achieving a dynamic balance between quadruple heat exchange and heat load.

[0040] It should be noted that several sets of fins 51 are fixedly connected around the outer surface of the chimney 5. Each set of fins 51 is spaced apart along the axial direction of the chimney 5 and perpendicular to the outer surface of the chimney 5. By increasing the contact area between the chimney 5 and the water between the boiler body 1 and the fire tube 3, the convective heat exchange efficiency between the flue gas and water is enhanced, thereby improving the first-stage heat exchange effect. The working medium 53 is an energy storage material with reversible phase change characteristics. When a phase change occurs, it is either a solid-solid phase change or a solid-liquid phase change. The preheating mechanism 9 includes two symmetrically arranged connecting pipes 91. The two connecting pipes 91 are respectively fixedly connected to the inner wall of the heat exchange layer 31 and extend... The preheating mechanism 9 also includes a fan 92 in the interlayer space between the fire tube 3 and the heat exchange layer 31. The fan 92 is connected to a connecting pipe 91 away from the output direction of the burner 2. Preheating is achieved by driving air to flow through the annular channel between the heat exchange layer 31 and the fire tube 3. The connecting pipe 91 near the burner 2 is sealed to the air inlet of the burner 2 through an external pipe. A flue pipe 6 is fixedly connected to the surface of the boiler body 1 on the side away from the burner 2. A cold water inlet 7 and a hot water outlet 8 are respectively installed on the top of the boiler body 1. Both the cold water inlet 7 and the hot water outlet 8 are connected to the boiler body 1 and the fire tube 3. The interlayer between tubes 3 is connected. An expansion valve connected to the interlayer between the boiler body 1 and the fire tubes 3 is installed at the top of the boiler body 1. The closed space formed by the tube sheet 4 at both ends between the boiler body 1 and the fire tubes 3 is a water heating chamber. The cold water inlet 7 and the hot water outlet 8 are both connected to this water heating chamber. The working medium 53 is encapsulated in the chamber between the chimney 5 and the heat exchange layer 52. The working medium 53 is palmitic acid, with a phase change temperature of 63-67℃, a latent heat of solid-liquid phase change of 195-200kJ / kg, a thermal conductivity of 0.15W / (m·K), and a volume expansion rate of 12-15%. The chamber filling rate is controlled at 80-85%, with a 15-20% expansion space reserved to buffer the phase change volume change. The phase change temperature of this medium is precisely matched with the target temperature of 60-80℃ for heating hot water. When the water temperature in the heating chamber is below 63℃, the medium solidifies and releases heat; when it is above 67℃, it melts and stores heat. The phase change platform maintains the water temperature stability. Its thermodynamic characteristics meet the dynamic balance requirements of heat storage during peak heat load and heat release during off-peak heat load. The 12-15% volume expansion rate and the reserved space in the chamber form a safety redundancy to ensure long-term operational reliability. An external scale inhibitor is installed on the surface of the cold water inlet 7.

[0041] Specifically, cold water is injected into the water heating chamber between the boiler body 1 and the fire tube 3 through the cold water inlet 7, and the inlet is closed after it is full.

[0042] When the burner 2 and preheating mechanism 9 are started, the burner 2 sprays out a flame, which is blocked by the tube sheet 4 and deflected back to form a return flame. As the flame extends to the far end of the fire tube 3, it continuously heats the fire tube 3 and the surrounding area.

[0043] Simultaneously, the blower 92 starts, drawing in air from the outside and delivering it through the connecting pipe 91, which is away from the output direction of the burner 2, to the interlayer space between the fire tube 3 and the heat exchange layer 31. As the air flows within the interlayer, it comes into full contact with the wall of the fire tube 3, which is preheated by the flame, absorbing heat and rising in temperature. Then, through the connecting pipe 91 near the burner 2 and external pipes, it is continuously delivered to the combustion end of the burner 2 as combustion air.

[0044] This continuous air preheating-combustion process utilizes the residual heat of the flame to raise the air temperature, reducing the fuel consumption of burner 2 in heating cold air, enhancing fuel combustion efficiency, and making the flame more stable and the heat release more complete.

[0045] It should be noted that in the air preheating-combustion process, there is a heat flow competition phenomenon: the flame heats the fire tube 3 to heat the water, while the air flowing in the interlayer absorbs heat from the wall of the fire tube 3 for preheating. This causes some of the heat transferred from the fire tube 3 to the subsequent water heating stage to be "intercepted" by the air. However, this heat flow competition is not an adverse effect, but rather forms a highly efficient energy transfer. From the perspective of energy distribution, the air preheating recovers about 30-40% of the waste heat from the flame, and the remaining 60-70% of the heat is still used to heat the fire tube 3 to achieve water heating. Through this proportional distribution, the waste heat of the flame is used to increase the air temperature, reducing the fuel consumption of the burner 2 in heating cold air, enhancing fuel combustion efficiency, making the flame more stable and the heat release more complete, and ensuring that the fire tube 3 has enough heat to continuously heat the water in the water heating chamber. This achieves a reasonable distribution and synergistic utilization of energy in the air preheating and water heating stages, making the energy utilization of the entire boiler system more efficient and the heat load easier to maintain a balance.

[0046] Meanwhile, the high-temperature flue gas generated by the return flame and combustion accumulates near the output end of the burner 2 to form a high-temperature flue gas zone. The initial temperature of this high-temperature flue gas can reach 800-1000℃ and flows along the surface of the heat exchange layer 2 52 inside the chimney 5, gradually flowing to the side away from the burner 2, and finally being discharged through the flue pipe 6.

[0047] During the flue gas flow process, the large amount of heat it carries is continuously transferred through the thin wall of the second heat exchange layer 52 to the working medium 53 in the interlayer between the chimney 5 and the second heat exchange layer 52.

[0048] The chimney 5 and heat exchange layer 52, which are close to the output end of the burner 2, are the first to come into contact with the high-temperature flue gas. The working medium 53 in this area quickly absorbs heat. When the initial water temperature in the water heating chamber is lower than the palmitic acid phase change temperature of 63°C, the palmitic acid quickly solidifies and releases the latent heat of phase change stored previously.

[0049] The released heat is first conducted to the wall of the chimney 5 through the thin wall of the heat exchange layer 52. The heat from the wall of the chimney 5 is directly transferred to the surrounding water on the one hand, and on the other hand, the heat is transferred to the water in the chamber with a larger contact area through the fins 51 on the outer surface, thus accelerating the heating of the water.

[0050] As the water temperature in the water heating chamber gradually increases, when the water temperature exceeds 67°C, the palmitic acid near the burner 2 and along the flue gas flow path absorbs heat and undergoes a melting phase change, storing the heat of the flue gas. At this time, the high-temperature flue gas continues to flow, and the working medium 53, which is far away from the burner 2, also gradually absorbs heat due to the residual heat of the flue gas, thus realizing the transfer and distribution of heat along the length of the chimney 5.

[0051] In addition, the fins 51 on the outer surface of the chimney 5 increase the contact area between the chimney 5 and the water. After the heat of the flue gas is transferred to the fins 51 through the chimney 5, the fins 51 make the heat exchange between the flue gas and the water more complete and faster, effectively avoiding the problem of local high temperature zone caused by heat concentration near the burner 2 in the traditional structure. Through the phase change heat storage and heat release of the working medium 53, combined with the enhanced heat exchange of the fins 51, the water temperature in the water heating chamber is uniformly and stably increased.

[0052] It should be noted that in traditional processes, the side near burner 2 is prone to forming a local high-temperature zone due to the accumulation of high-temperature flue gas. However, the working medium 53 palmitic acid melts and stores heat when there is excess heat in the high-temperature zone during the peak heat load, and solidifies and releases heat when the temperature drops during the trough. This can dynamically adjust the wall temperature of the chimney 5, avoid local overheating or overcooling, and make the water temperature in the water heating chamber tend to be stable.

[0053] As heat continues to transfer, the water in the water heating chamber gradually heats up. Once the target temperature is reached, the water is discharged through hot water outlet 8 for heating or other needs.

[0054] Throughout the process, the preheating mechanism 9 continuously supplies preheated air to the burner 2 to ensure efficient combustion; the working medium 53 balances the heat load by virtue of its phase change characteristics, and the fins 51 enhance heat exchange. The multi-stage collaboration achieves four-fold heat exchange: flame-air, flame-chimney 5, flue gas-working medium 53, and working medium 53-water, dynamically maintaining the heat load balance, ensuring stable and efficient boiler operation, and outputting hot water with uniform temperature.

[0055] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0056] Although embodiments of the 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 invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hot water boiler capable of maintaining heat load balance, comprising a boiler body (1), a burner (2) mounted on the surface of the boiler body (1), a fire tube (3) mounted inside the boiler body (1), tube plates (4) mounted on both sides of the fire tube (3), and a plurality of chimneys (5) fixedly connected between the tube plates (4) on both sides, characterized in that: The fire tube (3) has a heat exchange layer 1 (31) inside. A preheating mechanism (9) is installed between the heat exchange layer 1 (31) and the fire tube (3) and the burner (2). The chimney (5) has a heat exchange layer 2 (52) inside. The working medium (53) is stored between the heat exchange layer 2 (52) and the chimney (5). When the burner (2) is working, the flame is ejected from the output end of the burner (2) and extends to the far end of the fire tube (3). The preheating mechanism (9) delivers the air preheated by the flame to the combustion end to assist combustion. The flame is deflected when it encounters the tube sheet (4). A return flame is formed, creating a high-temperature flue gas zone near the output end of the burner (2). The high-temperature flue gas flows on the surface of the second heat exchange layer (52) and undergoes convective heat exchange with the water between the chimney (5) and the boiler body (1) and the fire tube (3). At the same time, the heat is transferred to the working medium (53) through the thin wall of the second heat exchange layer (52), causing it to absorb heat and undergo a phase change to store thermal energy. The working medium (53) stores heat during peak heat load and releases heat during trough. The phase change regulates the wall temperature of the chimney (5) to ensure the water temperature inside the boiler body (1) is stable, achieving a dynamic balance between quadruple heat exchange and heat load.

2. A hot water boiler capable of maintaining heat load balance according to claim 1, characterized in that: The outer surface of the chimney (5) is surrounded and fixedly connected with several sets of fins (51). Each set of fins (51) is distributed at intervals along the axial direction of the chimney (5) and is perpendicular to the outer surface of the chimney (5).

3. A hot water boiler capable of maintaining heat load balance according to claim 1, characterized in that: The working medium (53) is an energy storage material with reversible phase change characteristics, which is a solid-solid phase change or a solid-liquid phase change when a phase change occurs.

4. A hot water boiler capable of maintaining heat load balance according to claim 3, characterized in that: The preheating mechanism (9) includes two symmetrically arranged connecting pipes (91), which are respectively fixedly connected to the inner wall of the heat exchange layer (31) and extend to the interlayer space between the fire tube (3) and the heat exchange layer (31).

5. A hot water boiler capable of maintaining heat load balance according to claim 4, characterized in that: The preheating mechanism (9) also includes a fan (92), which is connected to a connecting pipe (91) away from the output direction of the burner (2) and preheats by driving air to flow through the annular channel between the heat exchange layer (31) and the fire tube (3).

6. A hot water boiler capable of maintaining heat load balance according to claim 5, characterized in that: The connecting pipe (91) near the burner (2) is sealed to the air inlet of the burner (2) through an external pipe.

7. A hot water boiler capable of maintaining heat load balance according to claim 3, characterized in that: The boiler body (1) has a flue pipe (6) fixedly connected to its surface and on the side away from the burner (2).

8. A hot water boiler capable of maintaining heat load balance according to claim 1, characterized in that: The top of the boiler body (1) is equipped with a cold water inlet (7) and a hot water outlet (8), and the cold water inlet (7) and the hot water outlet (8) are connected to the interlayer between the boiler body (1) and the fire tube (3).

9. A hot water boiler capable of maintaining heat load balance according to claim 8, characterized in that: An expansion valve is installed on the top of the boiler body (1) and communicates with the interlayer between the boiler body (1) and the fire tube (3).

10. A hot water boiler capable of maintaining heat load balance according to claim 8, characterized in that: The enclosed space formed between the boiler body (1) and the fire tube (3) and blocked at both ends by the tube sheet (4) is the water heating chamber. The cold water inlet (7) and the hot water outlet (8) are both connected to the water heating chamber.

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