A natural gas boiler

Abstract

This invention discloses a natural gas boiler, including a boiler with a lower support frame installed below it, a furnace body inside the boiler, and a flue gas heat exchange box behind the furnace body. An inner furnace cavity is formed within the furnace body, and a threaded furnace shell is installed within the inner furnace cavity. Combustion chambers are installed above and below the threaded furnace shell. A first flue gas chamber is provided within the combustion chamber, and a second flue gas chamber is embedded within the first flue gas chamber. By placing a concave heat-absorbing groove directly below the threaded furnace shell, as the burner continues to burn, heat is directly transferred to the arc-shaped heat-conducting fins to form primary waste heat utilization. Secondary waste heat utilization is then achieved through an externally connected spiral finned tube within the embedded flue gas pipe, thus maintaining the continuous heat of the purified water heated by the primary waste heat. Simultaneously, the heated purified water is input into an internal heating chamber, where hot water transfers heat and maintains the temperature of the water flow in the external heating chamber. The external heating chamber, in conjunction with the embedded flue gas pipe and the flue gas pipe heat exchange ring, forms tertiary waste heat utilization.

Description

Technical Field

[0001] This invention relates to the field of boiler equipment technology, specifically a natural gas boiler. Background Technology

[0002] A natural gas steam boiler is a type of gas-fired steam boiler. It is a heat energy conversion device that uses natural gas as fuel, and the heat released by the combustion of natural gas in the furnace heats the water in the boiler and vaporizes it into steam. The water in the boiler drum is continuously heated by the energy released by the combustion of gaseous fuel in the furnace, and the temperature rises to produce pressurized steam.

[0003] However, the existing technology has the following shortcomings: In the actual use of existing natural gas boilers, due to the continuous operation of the boiler, external purified water needs to be continuously supplied to the boiler. Before the water supply, the temperature of the purified water is between 30° and 45°, while the boiling point of the steam generated in the boiler is 100° or even higher. The continuous inflow of purified water not only lowers the temperature of the water in the boiler, but also indirectly increases the consumption of natural gas, resulting in high energy consumption and low steam conversion. Summary of the Invention

[0004] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description and other accompanying drawings.

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a natural gas boiler that, through continuous combustion of the burner, directly transfers heat to the arc-shaped heat-conducting fins to form primary waste heat utilization. Then, through the externally connected spiral finned tubes in the embedded flue, secondary waste heat utilization is formed, thus completing the continuous heat maintenance of the purified water after primary waste heat heating. At the same time, the heated purified water is input into the internal injection heating chamber, where the hot water in the internal injection heating chamber transfers heat and keeps the water flow in the external injection heating chamber warm. The external injection heating chamber, together with the embedded flue and the flue heat exchange ring, forms tertiary waste heat utilization.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a natural gas boiler, comprising a boiler with a lower support frame installed below it, a furnace body inside the boiler, a flue gas heat exchange box behind the furnace body, an inner furnace cavity formed within the furnace body, a threaded furnace liner installed within the inner furnace cavity, and combustion chambers installed above and below the threaded furnace liner; a first flue gas chamber is provided within the combustion chamber, a second flue gas chamber is embedded within the first flue gas chamber, and flue pipes are installed on both the second and first flue gas chambers; a connecting pipe is provided on the side wall of the first flue gas chamber, and a chimney connecting pipe is provided on the other side wall of the first flue gas chamber; a concave heat absorption groove is formed inside the second flue gas chamber. The concave heat absorption groove is mainly installed between the second and first flue gas chambers, directly facing the threaded furnace liner above, and utilizes the high temperature generated by combustion at the end of the threaded furnace liner.

[0007] A further improvement to the invention is that several sealing seats are installed on both the upper and lower surfaces of the concave heat-absorbing groove, and arc-shaped heat-conducting fins are installed in each of the sealing seats. The lower surface of the concave heat-absorbing groove is covered with a groove bottom cover, and an external spiral finned tube is connected to the side wall of the groove bottom cover. A finned connecting pipe is connected to the end of the external spiral finned tube, and a bidirectional discharge pipe is provided at the top of the finned connecting pipe. The external spiral finned tube mainly transports the water heated by the arc-shaped heat-conducting fins through the tube body, and then the external spiral fins absorb the heat of the flue gas, thus completing the heat preservation work for the water flow inside the tube.

[0008] A further improvement to the invention is that the arc-shaped heat-conducting fin is positioned directly above and in conjunction with the threaded furnace liner. The finned connecting pipe and the bidirectional discharge pipe are both located within the flue gas heat exchange box. The chimney connecting pipe is connected to the flue gas heat exchange box, and the connecting pipe connects the concave heat-absorbing groove and the bottom cover. The finned connecting pipe and the top-mounted bidirectional discharge pipe work together to complete the water output. The bottom cover primarily covers the bottom of the concave heat-absorbing groove, and by fully covering it, it works with the connecting pipe to complete the water input. The input water is heated within the enclosed space by the arc-shaped heat-conducting fin.

[0009] A further improvement to the present invention includes an insulated outer box within the flue gas heat exchange box, a sealing cover mounted on top of the insulated outer box, a flue gas pipe positioned in the center of the sealing cover, an inner cavity formed within the insulated outer box, an insulated inner box installed within the inner cavity, a pump connecting pipe mounted on the side wall of the insulated outer box, a furnace water supply pipe mounted on the side wall of the insulated outer box, a heat exchange box body installed within the insulated inner box, and a flue gas pipe connecting seat mounted on the heat exchange box body. The sealing cover primarily connects to the insulated outer box, collecting the heat generated by the embedded flue gas pipe within the inner cavity of the insulated outer box.

[0010] A further improvement to the present invention is that the heat exchange box contains an embedded flue pipe, and an external heating chamber is formed around the upper periphery of the embedded flue pipe. An internal heating chamber is located below the external heating chamber, and a mixing chamber is located below the internal heating chamber. An even number of three-way mixing and discharge valves are installed on the mixing chamber, and an even number of flue pipe heat exchange rings are installed at the upper end of the embedded flue pipe. The three-way mixing and discharge valves can be configured to maintain a fixed water supply ratio between the external and internal heating chambers, allowing the output water to be collected in the mixing chamber and then supplied to the boiler.

[0011] A further improvement to the invention is that the heat exchange ring portion of the flue pipe is disposed within the external injection heating chamber, and both the internal injection heating chamber and the external injection heating chamber are connected to the three-way mixing and discharge valve via pipes. The internal injection heating chamber primarily encloses the external injection heating chamber, with heat transfer occurring through the separating barrier between the two, and the internal injection heating chamber also provides insulation for the external injection heating chamber.

[0012] A further improvement to the present invention is that the embedded flue pipe is connected to the chimney connecting pipe, both ends of the bidirectional discharge pipe are connected to the internal heating chamber, the exhaust pipe is connected to the flue pipe connecting seat and to the embedded flue pipe, one end of the furnace body water supply branch pipe is connected to the mixing chamber, and the other end of the furnace body water supply branch pipe is connected to both sides of the furnace body. The furnace body water supply branch pipe mainly inputs water into the furnace body from both sides through the diversion of the pipeline, and the water supply branch pipe is connected to one side of the mixing chamber. After the water flow is mixed in a certain proportion, a high-temperature water flow is formed, which lowers the temperature of the water in the boiler after entering.

[0013] A further improvement to the present invention includes a control equipment mounting cover installed at the front of the furnace body, a burner installed at the top of the furnace body, an even number of safety valves located beside the burner, a steam exhaust pipe located beside the safety valves, a level gauge installed on the furnace body, and a purified water extraction pump located beside the flue gas heat exchange box. The purified water extraction pump is mainly used to connect the pipeline to the connecting pump pipe, the other end of which is fixed to the external injection heating chamber to complete the purified water input supply.

[0014] A further improvement to the invention is that wastewater discharge valve pipes are installed on both sides of the outer wall of the furnace body, a ladder is mounted on the outer wall of the furnace body, a heat exchange water supply pipe is installed next to the ladder, a controller is installed inside the control equipment mounting cover, an even number of pressure gauges are installed above the controller, and an emergency button is installed on the side wall of the controller. The emergency button is located on one side of the controller, mainly to facilitate rapid triggering in case of emergency, and also to avoid accidental contact with buttons located on the surface of the controller.

[0015] In a further improvement to the present invention, the heat exchange water supply pipe is connected to the connecting pipe, and the purified water pump is connected to the flue gas heat exchange box via a pipeline. The heat exchange water supply pipe also uses an external pump to pump purified water into the connecting pipe, which then flows into the bottom cover of the tank, thus forming a purified water supply.

[0016] Compared with the prior art, the present invention has the following beneficial effects;

[0017] This invention utilizes a concave heat-absorbing groove positioned directly below the threaded furnace chamber. As the burner continues to burn, heat is directly transferred to the arc-shaped heat-conducting fins, forming primary waste heat utilization. Secondary waste heat utilization is then achieved through an externally connected spiral finned tube within the embedded flue pipe, maintaining the heat of the purified water heated by the primary waste heat. Simultaneously, the heated water is input into the internal heating chamber, where hot water transfers heat and maintains the temperature of the water flow in the external heating chamber. The external heating chamber, in conjunction with the embedded flue pipe and its heat exchange ring, forms tertiary waste heat utilization. Ultimately, this maintains the boiler's water supply temperature at a consistently high level, indirectly reducing natural gas consumption and improving boiler efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a natural gas boiler according to the present invention;

[0019] Figure 2 This is a side view of the furnace body in a natural gas boiler according to the present invention;

[0020] Figure 3 This is a three-dimensional structural diagram of a flue gas heat exchange box in a natural gas boiler according to the present invention;

[0021] Figure 4 This is a partial cross-sectional view of the internal structure of the furnace body in a natural gas boiler according to the present invention;

[0022] Figure 5 This is a three-dimensional structural diagram of the combustion chamber in a natural gas boiler according to the present invention;

[0023] Figure 6 This is a bottom view of the internal structure of the concave heat absorption groove in a natural gas boiler according to the present invention.

[0024] Figure 7 This is a top view schematic diagram of the insulation outer casing in a natural gas boiler according to the present invention;

[0025] Figure 8 This is a three-dimensional structural diagram of the heat-insulating inner box in a natural gas boiler according to the present invention;

[0026] Figure 9 This is a front view of the internal structure of the heat exchange box in a natural gas boiler according to the present invention.

[0027] In the diagram: Boiler-1, Lower support frame-2, Furnace body-11, Control equipment mounting cover-12, Level gauge-13, Burner-14, Steam exhaust pipe-15, Safety valve-16, Flue gas heat exchange box-17, Clean water pump-18, Sewage discharge valve-111, Ladder-112, Heat exchange water supply pipe-113, Furnace inner cavity-114, Threaded furnace liner-115, Combustion chamber-116, Controller-121, Pressure gauge-122, Emergency button-123, Insulated outer box-171, Connecting pump pipe-172, Furnace body water supply diversion pipe-173, Sealing cover-174, Flue gas pipe-175, Box inner cavity-176, Insulated inner box-177, First flue gas return Chamber-1161, Second smoke chamber-1162, Smoke pipe-1163, Connecting pipe-1164, Smoke connecting pipe-1165, Concave heat absorption groove-1166, Groove bottom cover-11661, Sealing seat-11662, Arc-shaped heat conducting fin-11663, External connecting spiral finned tube-11664, Fin connecting pipe-116641, Bidirectional discharge pipe-116642, Heat exchange box-1771, Smoke pipe connecting seat-1772, External heating chamber-17711, Internal heating chamber-17712, Mixing chamber-17713, Three-way mixing discharge valve-17714, Embedded smoke pipe-17715, Smoke pipe heat exchange ring-177151. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0029] Furthermore, in the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0030] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral unit; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. However, specifying a direct connection indicates that the two main bodies are not connected through a transitional structure, but rather formed as a whole through a connecting structure. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0031] In this invention, unless otherwise expressly specified and limited, the first feature "on" or "below" the second feature may be in direct contact with the first and second features, or indirect contact through an intermediate medium. In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0032] The present invention will be further described below with reference to the accompanying drawings: Example 1

[0033] As attached Figure 1 To be continued Figure 9 As shown:

[0034] This embodiment provides a natural gas boiler, including a boiler 1, a lower support frame 2 installed below the boiler, a furnace body 11 inside the boiler 1, a flue gas heat exchange box 17 installed behind the furnace body 11, a control equipment mounting cover 12 installed in front of the furnace body 11, a burner 14 installed on the top of the furnace body 11, an even number of safety valves 16 installed next to the burner 14, a steam exhaust pipe 15 installed next to the safety valves 16, a level gauge 13 installed on the furnace body 11, and a clean water pump 18 installed next to the flue gas heat exchange box 17. Wastewater discharge valves 111 are installed on both sides of the outer wall of the furnace body 11. A ladder 112 is installed on the outer wall of the furnace body 11. A heat exchange water supply pipe 113 is installed next to the ladder 112. An inner furnace cavity 114 is formed inside the furnace body 11. A threaded furnace liner 115 is installed in the inner furnace cavity 114. A combustion chamber 116 is installed above and below the threaded furnace liner 115. A controller 121 is installed inside the control equipment mounting cover 12. An even number of pressure gauges 122 are installed above the controller 121. An emergency button 123 is installed on the side wall of the controller 121. The combustion chamber 116 is provided with a first smoke chamber 1161, and a second smoke chamber 1162 is embedded in the first smoke chamber 1161. Both the second smoke chamber 1162 and the first smoke chamber 1161 are equipped with smoke pipes 1163. A connecting pipe 1164 is provided on the side wall of the first smoke chamber 1161, and a chimney connecting pipe 1165 is provided on the other side wall of the first smoke chamber 1161. A concave heat absorption groove 1166 is opened in the second smoke chamber 1162. An insulated outer box 171 is installed inside the flue gas heat exchange box 17. A sealing cover 174 is installed on the top of the insulated outer box 171. A flue gas pipe 175 is installed in the center of the sealing cover 174. An inner cavity 176 is formed inside the insulated outer box 171. An insulated inner box 177 is installed in the inner cavity 176. A pump connecting pipe 172 is installed on the side wall of the insulated outer box 171. A furnace body water supply pipe 173 is installed on the side wall of the insulated outer box 171. A heat exchange box 1771 is installed in the insulated inner box 177. A flue gas pipe connecting seat 1772 is installed on the heat exchange box 1771. The concave heat absorption groove 1166 has several sealing seats 11662 installed on both its upper and lower surfaces. Each of the sealing seats 11662 has an arc-shaped heat-conducting fin 11663 installed in it. The lower surface of the concave heat absorption groove 1166 is covered with a bottom cover 11661. The side wall of the bottom cover 11661 is connected to an external spiral finned tube 11664. The end of the external spiral finned tube 11664 is connected to a finned connecting tube 116641. A bidirectional discharge pipe 116642 is provided at the top of the finned connecting tube 116641. The heat exchanger body 1771 has an embedded internal flue 17715. An external heating chamber 17711 is formed on the upper periphery of the internal flue 17715. An internal heating chamber 17712 is provided below the external heating chamber 17711. A mixing chamber 17713 is provided below the internal heating chamber 17712. An even number of three-way mixing and discharge valves 17714 are installed on the mixing chamber 17713. An even number of flue heat exchange rings 177151 are installed on the upper end of the internal flue 17715.

[0035] Furthermore, the water supply pump 18 and the externally connected water supply pump of the heat exchange water supply pipe 113 are both dynamically regulated by the controller 121. By changing the water supply, the external water flow is adjusted to match the water consumption of the boiler.

[0036] Furthermore, in addition to the combustion chamber 116 connected below, the threaded furnace 115 also has a first smoke return chamber 1161 nested on its top periphery. This first smoke return chamber 1161 is used to connect with the smoke pipe 1163 installed on the second smoke return chamber 1162. After the flue gas is input, the upper first smoke return chamber 1161, together with the smoke pipe 1163, inputs the flue gas into the lower first smoke return chamber 1161, thus forming a round trip of flue gas.

[0037] Furthermore, the arc-shaped heat-conducting plates 11663 are evenly distributed in a ring on the upper and lower surfaces of the concave heat-absorbing groove 1166. While absorbing heat generated by the upper threaded furnace liner 115, the heat is transferred to the arc-shaped heat-conducting plates 11663 on the lower surface. Finally, the supplied clean water is heated in the closed bottom cover 11661 of the groove, forming a primary waste heat utilization.

[0038] Furthermore, the external spiral finned tube 11664 is connected to the rear finned connecting tube 116641. The external spiral finned tube 11664 absorbs the waste heat of the flue gas in the first smoke chamber 1161 through the spiral fins on its surface, thereby utilizing the waste heat of the water flow in the tube body in a secondary manner and completing the heat preservation work of the water body in the tube.

[0039] Furthermore, the finned connecting pipe 116641 is installed vertically in the embedded flue pipe 17715, and the heat of the flue gas is collected by the fins on its surface, which, together with the external spiral finned pipe 11664 in front, forms the same water insulation work inside the pipe.

[0040] Furthermore, the insulated outer casing 171 insulates itself against the heat generated by the flue gas transmitted through the embedded flue pipe 17715. At the same time, the heat on the surface of the embedded flue pipe 17715 is transferred to the external heating chamber 17711 and the mixing chamber 17713 respectively. The heat exchange ring 177151 installed at the upper end of the embedded flue pipe 17715 transfers heat to the external heating chamber 17711, thus completing the heating of purified water.

[0041] Furthermore, the external heating chamber 17711 and the internal heating chamber 17712 have the same volume. However, since the water in the internal heating chamber 17712 is heated by the primary waste heat and its temperature is higher than that of the water flow in the external heating chamber 17711, and the two are separated by a barrier, the external heating chamber 17711 can be insulated and heat exchanged through the barrier.

[0042] Furthermore, the heat exchange ring 177151 is mainly installed on the upper end of the embedded flue 17715. After absorbing heat through the annular part embedded in the embedded flue 17715, it performs heat transfer work on the annular part inside the external heating chamber 17711, and realizes three-stage waste heat utilization.

[0043] Furthermore, the three-way mixing discharge valve 17714 is mainly connected to the external heating chamber 17711 and the internal heating chamber 17712 through pipelines. The preferred ratio of the internal heating chamber to the external heating chamber is 2.5:1 to complete the output of water to the mixing chamber 17713, mix the water temperature and maintain a high temperature.

[0044] The specific working principle is as follows:

[0045] This invention uses the lower support frame 2 to fix and support the boiler 1. The burner 14 on the furnace body 11 is connected to the natural gas pipeline to confirm the liquid level at the level gauge 13. The controller 121 on the control equipment mounting cover 12 controls the pressure gauge 122 as the internal pressure changes. The purified water pump 18 and the external pump of the heat exchange water supply pipe 113 work synchronously to pump the purified water into the insulated inner box 177 inside the insulated outer box 171 under the guidance of the connecting pump pipe 172. Meanwhile, the burner 14 works to continuously heat the threaded furnace 115. The flue gas generated by heating forms a reciprocating flow in the combustion chamber 116 through the flue pipe 1163 in the combustion chamber 116. The concave heat-absorbing groove 1166 on the second smoke chamber 1162 is directly below the threaded furnace liner 115. The arc-shaped heat-conducting plate 11663 on the sealing seat 11662 on the surface of the concave heat-absorbing groove 1166 absorbs the heat of the flue gas generated during combustion in the threaded furnace liner 115 and transfers it to the arc-shaped heat-conducting plate 11663 covered by the bottom cover 11661. The arc-shaped heat-conducting plate 11663 heats the clean water input into the connecting pipe 1164 inside the bottom cover 11661, forming a first-stage waste heat utilization. Then, the flue gas in the second smoke chamber 1162 is input into the first smoke chamber 1161 above through the smoke pipe 1163, and then the flue gas is discharged from the first smoke chamber 1161 above. The flue gas enters the first return smoke chamber 1161 below through the flue pipe 1163, forming a reversible return path. The flue gas is then discharged into the exhaust heat exchange box 17 from the flue gas connecting pipe 1165 installed on the first return smoke chamber 1161. The heat carried in the flue gas is absorbed through the finned connecting pipe 116641 and the external spiral finned pipe 11664, forming a heat insulation effect on the pipes, achieving secondary waste heat utilization. The heated water is then input into the internal heating chamber 17712 through the bidirectional discharge pipe 116642. The internal heating chamber 17712 then transfers heat and insulates the external heating chamber 17711. The external heating chamber 17711, through its embedded flue gas... The heat exchange ring 177151 at the upper end of the flue pipe 17715 transfers heat to the external heating chamber 17711 to heat the input purified water. Together with the internal heating chamber 17712, it forms a three-stage waste heat utilization. Finally, the hot water from the external heating chamber 17711 and the internal heating chamber 17712 is injected into the mixing chamber 17713 through the three-way mixing discharge valve 17714 at a ratio of 2.5:1. Then, it is supplied to the inside of the furnace body 11 by the furnace body water supply pipe 173. Thus, under the utilization of waste heat in the first, second and third stages, the water flow is always kept at a high temperature, which prevents the purified water entering the boiler 1 from lowering the temperature of the water in the boiler, indirectly saving natural gas consumption and improving the efficiency of the boiler.

[0046] It should be understood that the embodiments disclosed herein are not limited to the specific processing steps or materials disclosed herein, but should be extended to equivalent substitutions of such features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0047] The term "embodiment" in this specification means that a specific feature or characteristic described in connection with an embodiment is included in at least one embodiment of the invention. Therefore, phrases or "embodiments" appearing in various places throughout the specification do not necessarily refer to the same embodiment.

[0048] Furthermore, the described features or characteristics can be incorporated into one or more embodiments in any other suitable manner. In the above description, specific details, such as thickness, quantity, etc., are provided to provide a comprehensive understanding of embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented without the aforementioned specific details or may be implemented using other methods, components, materials, etc.

Claims

1. A natural gas boiler, characterized in that, The boiler (1) is provided with a lower support frame (2) installed below it. A furnace body (11) is provided inside the boiler (1). A flue gas heat exchange box (17) is provided behind the furnace body (11). A furnace cavity (114) is formed inside the furnace body (114). A threaded furnace liner (115) is installed in the furnace cavity (114). A combustion chamber (116) is installed above and below the threaded furnace liner (115). The combustion chamber (116) is provided with a first smoke return chamber (1161), and a second smoke return chamber (1162) is embedded in the first smoke return chamber (1161). Smoke pipes (1163) are installed on both the second smoke return chamber (1162) and the first smoke return chamber (1161). A connecting pipe (1164) is provided on the side wall of the first smoke return chamber (1161), and a chimney connecting pipe (1165) is provided on the other side wall of the first smoke return chamber (1161). A concave heat absorption groove (1166) is opened in the second smoke return chamber (1162). The concave heat absorption groove (1166) has several sealing seats (11662) installed on both its upper and lower surfaces. Each of the sealing seats (11662) has an arc-shaped heat-conducting plate (11663) installed in it. The lower surface of the concave heat absorption groove (1166) is covered with a bottom cover (11661). The side wall of the bottom cover (11661) is connected to an external spiral finned tube (11664). The end of the external spiral finned tube (11664) is connected to a finned connecting tube (116641). The top of the finned connecting tube (116641) is provided with a bidirectional discharge pipe (116642). One of the arc-shaped heat-conducting plates (11663) is directly above the threaded furnace liner (115) and cooperates with it. The fin connecting pipe (116641) and the bidirectional discharge pipe (116642) are both arranged in the flue gas heat exchange box (17). The chimney connecting pipe (1165) is connected to the flue gas heat exchange box (17). The connecting pipe (1164) is connected between the concave heat absorption groove (1166) and the bottom cover (11661). The exhaust heat exchange box (17) is equipped with an insulated outer box (171), and a sealing cover (174) is installed on the top of the insulated outer box (171). An exhaust pipe (175) is installed in the center of the sealing cover (174). An inner cavity (176) is formed inside the insulated outer box (171). An insulated inner box (177) is installed in the inner cavity (176). A pump connecting pipe (172) is installed on the side wall of the insulated outer box (171). A furnace body water supply pipe (173) is installed on the side wall of the insulated outer box (171). A heat exchange box body (1771) is installed in the insulated inner box (177). A flue pipe connecting seat (1772) is installed on the heat exchange box body (1771).

2. A natural gas boiler according to claim 1, characterized in that: The heat exchange box (1771) has an embedded internal flue (17715). An external heating chamber (17711) is formed on the outer periphery of the upper end of the embedded flue (17715). An internal heating chamber (17712) is provided below the external heating chamber (17711). A mixing chamber (17713) is provided below the internal heating chamber (17712). An even number of three-way mixing and discharge valves (17714) are installed on the mixing chamber (17713). An even number of flue heat exchange rings (177151) are installed on the upper end of the embedded flue (17715).

3. A natural gas boiler according to claim 2, characterized in that: The heat exchange ring (177151) of the flue is partially disposed in the external injection heating chamber (17711), and the internal injection heating chamber (17712) and the external injection heating chamber (17711) are both connected to the three-way mixing discharge valve (17714) through pipes.

4. A natural gas boiler according to claim 2, characterized in that: The embedded flue (17715) is connected to the chimney connecting pipe (1165), both ends of the bidirectional discharge pipe (116642) are connected to the internal heating chamber (17712), the exhaust pipe (175) is connected to the flue connecting seat (1772) and connected to the embedded flue (17715), one end of the furnace body water supply pipe (173) is connected to the mixing chamber (17713), and the other end of the furnace body water supply pipe (173) is connected to both sides of the furnace body (11).

5. A natural gas boiler according to claim 4, characterized in that: A control equipment mounting cover (12) is installed in front of the furnace body (11), a burner (14) is installed on the top of the furnace body (11), an even number of safety valves (16) are provided next to the burner (14), a steam exhaust pipe (15) is provided next to the safety valves (16), a liquid level gauge (13) is installed on the furnace body (11), and a clean water pump (18) is provided next to the flue gas heat exchange box (17).

6. A natural gas boiler according to claim 5, characterized in that: Wastewater discharge valve pipes (111) are installed on both sides of the outer wall of the furnace body (11). A ladder (112) is installed on the outer wall of the furnace body (11). A heat exchange water supply pipe (113) is installed next to the ladder (112). A controller (121) is installed inside the control equipment mounting cover (12). An even number of pressure gauges (122) are installed above the controller (121). An emergency button (123) is installed on the side wall of the controller (121).

7. A natural gas boiler according to claim 6, characterized in that: The heat exchange water supply pipe (113) is connected to the connecting pipe (1164), and the purified water pump (18) is connected to the flue gas heat exchange box (17) through a pipe.

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