Natural gas hot air furnace

Abstract

This invention discloses a natural gas hot air furnace, belonging to the field of industrial hot air heating technology. It includes a furnace body, a burner, and a heat exchange section. The heat exchange section has a negative pressure chamber, and the bottom surface of the negative pressure chamber is equipped with a flue gas outlet with heat exchange tubes. The burner has a combustion head coaxial with the heat exchange tubes. The inner wall of the furnace body is fitted with a high-temperature regenerative refractory jacket, forming an annular flow channel between the refractory jacket and the heat exchange tubes. A negative pressure injection combustion-aiding air inlet gap is reserved between the bottom conical shroud and the combustion head. This invention, through the high-temperature regenerative refractory jacket, the conical shroud, and the annular flow channel forming a coaxial flame beam structure, combined with micro-negative pressure traction, can smoothly stretch the natural gas flame axially into a regular columnar flame, eliminating the problems of flame divergence, deflection, and turbulent flow in traditional hot air furnaces. Simultaneously, relying on the flame-stabilizing effect of the inner hot wall of the high-temperature regenerative refractory jacket, it effectively avoids faults such as negative pressure flameout, flame interruption, backfire, and smoke leakage.

Description

Technical Field

[0001] This invention relates to the field of industrial hot air heating technology, and more specifically, to a natural gas hot air furnace. Background Technology

[0002] In industries such as industrial drying, material drying, workshop process heating, chemical reaction heating, agricultural product drying, and building material maintenance, natural gas hot air furnaces have become the mainstream heat energy supply equipment due to their advantages of being clean and environmentally friendly, having high thermal efficiency, and being easy to start and stop. Currently, traditional natural gas hot air furnaces on the market still have many structural and operational defects, which seriously restrict combustion efficiency, heat exchange performance, and equipment operational stability.

[0003] Traditional hot blast stoves lack dedicated axial flame ignition, flame confinement, and regular flow guiding structures. The natural gas flame ejected from the burner head lacks directional constraint, easily leading to flame divergence, deflection, and turbulent flow. This prevents the formation of a regular columnar flame, which cannot uniformly coat the heat exchange tube walls, resulting in uneven heating of the heat exchange surface, localized overheating and erosion, and localized low-temperature heat exchange failure. Furthermore, the lack of a reasonable negative pressure injection combustion-supporting layout within the furnace allows for disordered entry of combustion-supporting fresh air into the combustion zone, resulting in poor air-fuel ratio matching and frequent malfunctions such as negative pressure flameout, flame interruption, backfire and smoke leakage, and combustion detonation, leading to low equipment reliability. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a natural gas hot blast stove that forms a coaxial flame beam structure through a high-temperature regenerative refractory jacket, a conical hood, and an annular flow channel. Combined with micro-negative pressure traction, this structure can smoothly stretch the natural gas flame axially into a regular columnar flame, eliminating the problems of flame dispersion, deflection, and turbulent flow in traditional hot blast stoves. At the same time, relying on the flame stabilization effect of the inner hot wall of the high-temperature regenerative refractory jacket, it effectively avoids faults such as negative pressure flameout, flame interruption, backfire, and smoke leakage. The air-flame matching degree is high, and the combustion conditions are stable and controllable throughout the entire process.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A natural gas hot air furnace includes a furnace body, a burner fixed to the bottom surface of the furnace body, and a heat exchange section fixedly installed inside the furnace body; the heat exchange section includes a negative pressure chamber; a plurality of flue gas outlets are uniformly arranged through the bottom surface of the negative pressure chamber; and heat exchange tubes are coaxially arranged inside the flue gas outlets.

[0007] The burner surface is uniformly provided with several burn heads coaxial with the corresponding heat exchange tubes; the inner wall of the furnace is uniformly provided with several high-temperature regenerative refractory jackets coaxial with the heat exchange tubes.

[0008] The inner side of the high-temperature regenerative refractory jacket and the outer wall of the corresponding heat exchange tube form an annular flow channel of equal width; a conical hood is fixed at the bottom of the high-temperature regenerative refractory jacket; a negative pressure ejector combustion air inlet gap is reserved between the combustion head and the bottom of the conical hood.

[0009] The annular flow channel and the negative pressure ejector combustion air inlet gap are used to concentrate the flame and guide the flow of smoke, and together with the micro negative pressure, achieve stable axial stretching of the flame and orderly upward movement of the smoke.

[0010] The invention is further configured such that: support plates are symmetrically fixed inside the furnace body; an annular plate coaxial with the furnace body is fixed between the two support plates; each set of high-temperature heat storage refractory sleeves is uniformly fixed on the inner wall of the annular plate; a sealing ring is fixed at the top of the high-temperature heat storage refractory sleeve; and a sealing groove adapted to the sealing ring is opened at the bottom of the flue gas outlet.

[0011] The present invention is further configured such that: the high-temperature heat storage fire jacket is a double-layer composite integrated structure, the inner layer is a high heat storage fire jacket, and the outer layer is a lightweight heat insulation layer.

[0012] The invention is further configured such that the interior of the smoke exhaust port has a structure that is narrow at the top and wide at the bottom, and the diameter of its lower port is consistent with the inner diameter of the high-temperature heat storage fire-resistant jacket.

[0013] The invention is further configured such that: a heat exchange plate coaxial with the negative pressure chamber is fixed on the bottom surface of the chamber; an air inlet pipe is fixed on the bottom surface of the heat exchange plate; a plurality of air inlets are evenly opened on the periphery of the air inlet pipe; the air inlet pipe is connected to an external cold air delivery pipe; a plurality of partitions are evenly fixed between the air inlet pipe and the inner wall of the heat exchange plate; a plurality of staggered baffles are provided on the opposite sides of the partitions; and the baffles between adjacent partitions form a serpentine heat exchange channel.

[0014] The invention is further configured such that: an air supply pipe and an air exhaust pipe are sequentially connected to the top of the heat exchange tube; a guide plate is fixed to the top of the heat exchange tube; the guide plate divides the interior of the heat exchange tube into a U-shaped heat exchange channel; an annular transfer box is fixed to the outer wall of the negative pressure chamber; a hot air pipe is connected to the top of the annular transfer box; an annular fixing plate is fixed to the bottom of the annular transfer box; and the annular fixing plate is fixedly connected to the outer wall of the furnace body by fastening bolts.

[0015] The invention is further configured such that: a sealing cover plate is fixed to the top of the negative pressure chamber and is inserted into the top of the negative pressure chamber; a clearance opening coaxial with the air inlet pipe is opened on the inner bottom surface of the sealing cover plate; the sealing cover plate is fixed to the top of the negative pressure chamber by fastening bolts; an insulation box is provided above the sealing cover plate; a plurality of connecting pipes are provided between the insulation box and the sealing cover plate; the connecting pipes are connected to the negative pressure chamber; a smoke exhaust pipe is provided on the outer wall of the insulation box; the smoke exhaust pipe is connected to the external negative pressure pipe.

[0016] The advantages of this invention are:

[0017] 1. This invention forms a coaxial flame beam structure by using a high-temperature regenerative refractory jacket, a conical hood, and an annular flow channel. Combined with the -5Pa to -20Pa micro-negative pressure traction of the negative pressure chamber, the natural gas flame can be axially stretched into a regular columnar flame, eliminating the problems of flame divergence, deflection, and turbulent flow in traditional hot blast stoves. At the same time, relying on the flame stabilization effect of the inner hot wall of the high-temperature regenerative refractory jacket, it effectively avoids faults such as negative pressure flameout, flame interruption, backfire, and smoke leakage. The air-flame matching degree is high, and the combustion conditions are stable and controllable throughout the entire process.

[0018] 2. This invention utilizes the gap between the negative pressure ejector and the combustion-supporting air intake to automatically eject external air with micro-negative pressure to form a uniform secondary combustion-supporting air. The air ratio is reasonable and the mixing is sufficient, which improves the completeness of natural gas combustion and effectively reduces natural gas consumption. At the same time, the high-temperature heat storage refractory jacket adopts a double-layer composite structure. The outer lightweight heat insulation layer locks in the heat inside the furnace, reduces the heat loss of the furnace body, and reduces the operating energy consumption.

[0019] 3. This invention extends the heat exchange path and residence time of cold air by setting up a dual heat exchange structure of serpentine heat exchange channel and U-shaped heat exchange tube; the annular flow channel forms a high-speed upward flue gas flow that adheres to the wall, breaks up the static heat insulation boundary layer of flue gas on the heat exchange tube wall, reduces the heat exchange thermal resistance, realizes efficient heat exchange between flue gas and air, and improves the overall heat exchange efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a natural gas hot air furnace according to the present invention.

[0021] Figure 2 For the present invention Figure 1 A partial sectional view.

[0022] Figure 3 For the present invention Figure 2 A structural diagram from a frontal viewpoint.

[0023] Figure 4 For the present invention Figure 3 Enlarged view of region A.

[0024] Figure 5 This is a schematic diagram of the furnace body of the present invention.

[0025] Figure 6 This is a schematic diagram of the heat exchange section of the present invention.

[0026] Figure 7 This is a schematic diagram of the heat exchange section of the present invention from another angle.

[0027] Figure 8 For the present invention Figure 6 A structural diagram from a top-down perspective.

[0028] Figure 9This is a partial cross-sectional view of the heat exchange section of the present invention.

[0029] Figure 10 This is a partial cross-sectional view of the sealing cover plate of the present invention.

[0030] In the diagram: 1. Furnace body; 2. Burner; 3. Heat exchange section; 4. Negative pressure chamber; 5. Exhaust port; 6. Heat exchange tube; 7. Burner head; 8. High-temperature regenerative refractory jacket; 9. Annular flow channel; 10. Negative pressure ejector combustion air inlet gap; 11. Support plate; 12. Annular plate; 13. Sealing ring; 14. Sealing groove; 15. Heat exchange plate; 16. Air inlet pipe; 17. Baffle plate; 18. Baffle; 19. Air conveying pipe; 20. Exhaust pipe; 21. Guide plate; 22. Annular transfer box; 23. Hot air pipe; 24. Annular fixing plate; 25. Sealing cover plate; 26. Circumvention port; 27. Insulation box; 28. Connecting pipe; 29. ​​Conical cover; 30. Air inlet. Detailed Implementation

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0033] In this invention, unless otherwise stated, the directional terms such as "up" and "down" generally refer to the directions shown in the accompanying drawings, or to the vertical, perpendicular, or gravitational direction; similarly, for ease of understanding and description, "left" and "right" generally refer to the left and right shown in the accompanying drawings; "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0034] Example 1, please refer to Figure 1-10 The present invention provides the following technical solutions:

[0035] A natural gas hot air furnace specifically includes a furnace body 1, a burner 2 fixed to the bottom surface of the furnace body 1, and a heat exchange section 3 fixedly installed inside the furnace body 1; the heat exchange section 3 includes a negative pressure chamber 4; a plurality of exhaust ports 5 are uniformly arranged through the bottom surface of the negative pressure chamber 4; and heat exchange tubes 6 are coaxially arranged inside the exhaust ports 5.

[0036] The surface of the burner 2 is uniformly provided with a number of burner heads 7 that are coaxial with the corresponding heat exchange tubes 6; the inner wall of the furnace body 1 is uniformly provided with a number of high-temperature regenerative refractory jackets 8 that are coaxial with the heat exchange tubes 6.

[0037] The inner side of the high-temperature regenerative refractory jacket 8 and the outer wall of the corresponding heat exchange tube 6 form an annular flow channel 9 of equal width, which limits and accelerates the flow of flue gas, causing the flue gas to form an upward flow field attached to the wall. This effectively breaks up the static heat insulation boundary layer of the flue gas on the outer wall of the heat exchange tube 6, reduces the heat exchange resistance, and improves the heat exchange efficiency. At the same time, the high-speed flue gas continuously and fully adheres to the wall and washes the tube wall of the heat exchange tube 6, forming a dynamic self-cleaning effect. This can effectively inhibit the adhesion and accumulation of carbon particles and dust, ensuring that the heat exchange efficiency of the equipment does not decrease significantly during long-term operation. A conical hood 29 is fixed at the bottom of the high-temperature regenerative refractory jacket 8. A negative pressure injection combustion air inlet gap 10 is reserved between the burner head 7 and the bottom of the conical hood 29. Relying on the micro-negative pressure environment in the negative pressure chamber 4, external air is actively injected to provide uniform and stable secondary combustion air for natural gas combustion, improve combustion completeness, reduce natural gas consumption, and reduce the emission of exhaust pollutants caused by incomplete combustion. The working negative pressure inside the negative pressure chamber 4 is stably controlled at -5Pa to -20Pa.

[0038] The annular flow channel 9 and the negative pressure ejector combustion air inlet gap 10 are used to concentrate the flame and guide the flow of the smoke. With the help of micro negative pressure, the flame is stretched axially and the smoke rises in an orderly manner, effectively preventing operational failures such as flame deviation, flame turbulence, negative pressure flameout and flue gas backflow disorder.

[0039] Working principle of this embodiment:

[0040] After the equipment is officially started, the burner 2 enters the working state, and each burner head 7 synchronously injects natural gas and completes ignition. The flame generated by combustion is vertically upward and aimed at the internal space of the high-temperature regenerative refractory jacket 8. Under the converging and guiding effect of the conical shroud 29 and the axial traction effect of the slight negative pressure in the negative pressure chamber 4, the originally short flame is steadily stretched into a regular columnar flame column, which completely wraps the outer wall of the heat exchange tube 6 for radiant heating.

[0041] Outside the furnace body 1, ambient temperature air is automatically drawn into the furnace through the negative pressure ejector combustion air inlet gap 10, supplementing the combustion zone to participate in secondary combustion and ensuring complete combustion of natural gas. The flue gas generated by combustion flows upward at high speed along the annular flow channel 9, scouring the outer wall of the heat exchange tube 6 for high-intensity convective heat exchange. After heat exchange, the flue gas flows into the negative pressure chamber 4 through the exhaust port 5 and is finally discharged.

[0042] Throughout the entire operation, the flame shape is stable and regular, the flue gas flow field is evenly and orderly distributed, the heat exchange area utilization rate is high, the overall heat loss is low, and the combustion conditions are stable.

[0043] Example 2, please refer to Figure 1-10This second embodiment is an improvement on the first embodiment as follows: Specifically, support plates 11 are symmetrically fixed inside the furnace body 1; an annular plate 12 coaxial with the furnace body 1 is fixed between the two support plates 11; each group of high-temperature heat storage refractory jackets 8 is evenly fixed on the inner wall of the annular plate 12; a sealing ring 13 is fixed on the top of the high-temperature heat storage refractory jacket 8; a sealing groove 14 adapted to the sealing ring 13 is opened at the bottom of the flue gas outlet 5. Through the embedded sealing cooperation between the sealing ring 13 and the sealing groove 14, the connection gap can be sealed to prevent the flue gas from leaking and dissipating heat from the splicing gap. At the same time, the heat exchange pipes 6 inside each group of high-temperature heat storage refractory jackets 8 are independent of each other, avoiding flue gas crosstalk and negative pressure interference, and ensuring the balanced and stable negative pressure conditions of a single group and the whole machine.

[0044] The high-temperature heat storage refractory jacket 8 has a double-layer composite integrated structure. Its inner layer is a high heat storage refractory layer made of high-alumina refractory castable / ceramic refractory material, which is resistant to high temperature, has strong heat storage performance, does not fall off or soften, and the inner wall of the inner layer stores high-temperature heat for a long time, forming a hot wall flame stabilization effect, preventing the flame from being pulled off or detached by a slight negative pressure, while also constraining the flame to rise in a regular manner. Its outer layer is a lightweight heat insulation layer made of lightweight heat insulation refractory material with low thermal conductivity, which locks in the internal temperature of the high-temperature heat storage refractory jacket 8 and reduces heat loss.

[0045] The exhaust port 5 has a narrow top and wide bottom structure, and its lower port diameter is consistent with the inner diameter of the high-temperature heat storage refractory jacket 8. The top flow resistance of the exhaust port 5 is uniform and the flow is balanced. This structure can gather the upward flue gas, regulate the flow field direction, and balance the flow resistance of the inner diameter of each group of high-temperature heat storage refractory jackets 8. This avoids problems such as wind grabbing, uneven negative pressure, and operating condition deviation during the operation of multi-unit arrays, ensuring the uniformity of the combustion and heat exchange conditions of the whole machine, while preventing flue gas turbulence and backflow and improving the stability of the micro-negative pressure flame.

[0046] A heat exchange plate 15, coaxial with the negative pressure chamber 4, is fixed to the bottom surface of the chamber. An air inlet pipe 16 is fixed to the bottom surface of the heat exchange plate 15. Several air inlets 30 are evenly opened on the circumference of the air inlet pipe 16. The air inlet pipe 16 is connected to an external cold air delivery pipe. Several baffles 17 are evenly fixed between the air inlet pipe 16 and the inner wall of the heat exchange plate 15. Several staggered baffles 18 are provided on opposite sides of the baffles 17. Each set of baffles 18 between two adjacent baffles 17 forms a serpentine heat exchange channel. The externally delivered cold air is diverted into the corresponding serpentine heat exchange channel through the air inlets 30 on the air inlet pipe 16. It flows slowly along the meandering channel and preheats the flue gas trapped inside the negative pressure chamber 4, thereby increasing the initial inlet temperature of the cold air, reducing the subsequent heat exchange temperature difference, and further improving the overall heat exchange efficiency and outlet temperature stability of the hot air preparation.

[0047] The top of the heat exchange tube 6 is connected to an air supply pipe 19 and an exhaust pipe 20 in sequence; a guide plate 21 is fixed inside the top of the heat exchange tube 6; the guide plate 21 divides the inside of the heat exchange tube 6 into a U-shaped heat exchange channel, extending the flow path and heat residence time of the cold air inside the heat exchange tube 6, allowing the cold air to fully exchange heat with the tube wall of the heat exchange tube 6, and improving the air temperature rise effect; an annular transfer box 22 is fixed to the outer wall of the negative pressure chamber 4; a hot air pipe 23 is connected to the top of the annular transfer box 22; an annular fixing plate 24 is fixed to the bottom of the annular transfer box 22; the annular fixing plate 24 is fixed to the outer wall of the furnace body 1 by fastening bolts.

[0048] A sealing cover plate 25 is fixed to the top of the negative pressure chamber 4 and is inserted into the top of the negative pressure chamber 4; an avoidance opening 26 coaxial with the air inlet pipe 16 is opened on the inner bottom surface of the sealing cover plate 25; the sealing cover plate 25 is fixed to the top of the negative pressure chamber 4 by fastening bolts; an insulation box 27 is set above the sealing cover plate 25; several connecting pipes 28 are connected between the insulation box 27 and the sealing cover plate 25; the connecting pipes 28 are connected to the negative pressure chamber 4; an exhaust pipe is connected to the outer wall of the insulation box 27; the exhaust pipe is connected to an external negative pressure pipe, and the exhaust pipe is connected to a variable frequency negative pressure induced draft fan. When the variable frequency negative pressure induced draft fan is running, it draws air and stabilizes the pressure inside the negative pressure chamber 4 at a uniform speed through the insulation box 27 and the connecting pipes 28, so that the inside of the negative pressure chamber 4 is stably maintained in a micro negative pressure range of -5Pa to -20Pa, providing a continuous and stable negative pressure power source for negative pressure injection combustion, flame beam guiding, and orderly upward movement of flue gas.

[0049] Negative pressure detection employs a dedicated pressure tap on the side wall of negative pressure chamber 4, connected to an external micro differential pressure transmitter to collect the static negative pressure value inside the chamber in real time. The transmitter converts the physical quantity of negative pressure into a 4-20mA analog signal and inputs it into the PLC controller. The PLC presets a micro negative pressure target range of -5Pa to -20Pa, and compares the detected negative pressure with the set negative pressure in real time through a PID closed-loop algorithm. It automatically adjusts the speed of the variable frequency negative pressure induced draft fan at the end of the exhaust pipe, and uses an electric bypass regulating valve to fine-tune the pressure relief, so that the inside of negative pressure chamber 4 is always stably maintained within the set micro negative pressure range. Relying on real-time negative pressure detection and closed-loop control, a constant negative pressure condition is provided for the induced draft of the negative pressure injection combustion air inlet gap 10, the coaxial flame stabilization of the high-temperature heat storage fire jacket 8, and the orderly upward flow of flue gas in the annular flow channel 9, suppressing problems such as flameout, flame interruption, backfire, smoke leakage, and flue gas turbulence caused by negative pressure fluctuations.

[0050] Working principle of this embodiment two:

[0051] When the equipment is running, the external negative pressure exhaust fan is first started, and the air is drawn into the negative pressure chamber 4 at a uniform speed through the insulation box 27 and the connecting pipe 28, so that the negative pressure chamber 4 can be quickly established and stably maintained in a micro negative pressure environment of -5Pa to -20Pa, providing basic working conditions for the whole machine to eject, stabilize the flame and guide the flow.

[0052] Subsequently, burner 2 is activated, and each burner head 7 synchronously injects natural gas and automatically ignites it. Under the combined effects of micro-negative pressure axial traction, conical shroud 29 converging and guiding the flow, and high-temperature regenerative refractory jacket 8 stabilizing the flame, the initial short flame is smoothly elongated axially, forming a uniform, consistent columnar flame column. The effective heat exchange height of the high-temperature regenerative refractory jacket 8 is not less than the effective heat exchange height of the heat exchange tube 6. The flame column and flue gas can fully, along the entire length and circumference, cover the outer wall of the heat exchange tube 6, completely solving the industry pain points of local overheating and erosion, uneven heating of the tube wall, and large thermal deviation of the entire machine in traditional hot blast stoves.

[0053] External ambient temperature cold air is delivered into the air inlet duct 16 via a cold air delivery pipeline. It is then evenly distributed into the serpentine heat exchange channel inside the heat exchange plate 15 through the circumferentially distributed air inlets 30, where it undergoes preheating with the flue gas in the negative pressure chamber 4. The preheated cold air is then introduced into the U-shaped heat exchange channel inside the heat exchange tube 6 via the air delivery duct 19. It flows slowly along the meandering channel, fully absorbing the radiant and convective heat from the tube wall of the heat exchange tube 6, thus completing a secondary deep heating process.

[0054] The fully heated high-temperature hot air flows into the annular transfer box 22 through the exhaust pipe 20. After being stabilized and evenly distributed by the annular transfer box 22, the hot air is continuously output to the outside through the top hot air pipe 23 with a constant temperature and stable air volume. The flue gas after combustion heat exchange is completed flows into the negative pressure chamber 4 through the exhaust port 5, and then passes through the connecting pipe 28, the insulation box 27, and the exhaust pipe in sequence through the negative pressure pipeline for centralized discharge.

[0055] The double-layer composite high-temperature heat storage refractory jacket 8 combines multiple functions such as flame stabilization and heat storage, flow field regulation, and heat insulation, effectively reducing heat loss; the annular flow channel 9 enables high-speed wall-mounted airflow to achieve dynamic self-cleaning of the pipe wall, extending the maintenance-free operation cycle of the equipment; the dual heat exchange structure of the front serpentine heat exchange channel and the U-shaped heat exchange channel inside the pipe provides a long heat exchange path and sufficient heat exchange. The whole machine has comprehensive advantages such as complete combustion, high heat exchange efficiency, low heat loss, stable air output, reliable operation, and simple maintenance.

[0056] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0057] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0058] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0060] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A natural gas hot air furnace, comprising a furnace body (1), a burner (2) fixed to the bottom surface of the furnace body (1), and a heat exchange section (3) fixedly installed inside the furnace body (1); characterized in that: The heat exchange section (3) includes a negative pressure chamber (4); several exhaust ports (5) are uniformly arranged through the bottom surface of the negative pressure chamber (4); heat exchange tubes (6) are coaxially arranged inside the exhaust ports (5); The burner (2) has several burn heads (7) that are coaxial with the corresponding heat exchange tubes (6) evenly arranged on its surface; the furnace body (1) has several high-temperature regenerative refractory jackets (8) that are coaxial with the heat exchange tubes (6) evenly arranged on its inner wall. The inner side of the high-temperature heat storage refractory jacket (8) and the outer wall of the corresponding heat exchange tube (6) form an annular flow channel (9) of equal width; a conical hood (29) is fixed at the bottom of the high-temperature heat storage refractory jacket (8); a negative pressure injection combustion air inlet gap (10) is reserved between the burner head (7) and the bottom end of the conical hood (29). The annular flow channel (9) and the negative pressure ejector combustion air inlet gap (10) are used to concentrate the flame and guide the flow of the smoke, and with the help of micro negative pressure, the flame is stretched axially and the smoke rises in an orderly manner.

2. A natural gas hot blast stove according to claim 1, characterized in that: The furnace body (1) is symmetrically fixed with support plates (11); between the two support plates (11) is an annular plate (12) coaxial with the furnace body (1); each set of high temperature heat storage refractory sleeves (8) is evenly fixed on the inner wall of the annular plate (12); a sealing ring (13) is fixed on the top of the high temperature heat storage refractory sleeves (8); a sealing groove (14) matching the sealing ring (13) is opened at the bottom of the flue gas outlet (5).

3. A natural gas hot blast stove according to claim 1, characterized in that: The high-temperature heat storage fire jacket (8) is a double-layer composite integrated structure, with its inner layer being a high heat storage fire layer and its outer layer being a lightweight heat insulation layer.

4. A natural gas hot blast stove according to claim 1, characterized in that: The smoke exhaust port (5) has a narrow upper and wide lower structure, and its lower port diameter is consistent with the inner diameter of the high-temperature heat storage fire-resistant jacket (8).

5. A natural gas hot blast stove according to claim 1, characterized in that: A heat exchange plate (15) coaxial with the bottom surface of the negative pressure chamber (4) is fixed; an air inlet pipe (16) is fixed on the bottom surface of the heat exchange plate (15); several air inlets (30) are evenly opened on the periphery of the air inlet pipe (16); the air inlet pipe (16) is connected to the external cold air delivery pipe; several partitions (17) are evenly fixed between the air inlet pipe (16) and the inner wall of the heat exchange plate (15); several staggered baffles (18) are provided on the opposite sides of the partitions (17); the baffles (18) between two adjacent partitions (17) form a serpentine heat exchange channel.

6. A natural gas hot blast stove according to claim 1, characterized in that: The top of the heat exchange tube (6) is connected to an air supply pipe (19) and an exhaust pipe (20); a guide plate (21) is fixed inside the top of the heat exchange tube (6); the guide plate (21) divides the inside of the heat exchange tube (6) into a U-shaped heat exchange channel; an annular transfer box (22) is fixed to the outer wall of the negative pressure chamber (4); a hot air pipe (23) is connected to the top of the annular transfer box (22); an annular fixing plate (24) is fixed to the bottom of the annular transfer box (22); the annular fixing plate (24) is fixed to the outer wall of the furnace body (1) by fastening bolts.

7. A natural gas hot air furnace according to claim 5, characterized in that: A sealing cover plate (25) is fixed to the top of the negative pressure chamber (4) and is inserted into the top of the negative pressure chamber (4); the bottom surface of the sealing cover plate (25) is provided with a clearance opening (26) coaxial with the air inlet pipe (16); the sealing cover plate (25) is fixed to the top of the negative pressure chamber (4) by fastening bolts; an insulation box (27) is provided above the sealing cover plate (25); several connecting pipes (28) are provided between the insulation box (27) and the sealing cover plate (25); the connecting pipes (28) are connected to the negative pressure chamber (4); an exhaust pipe is provided on the outer wall of the insulation box (27); the exhaust pipe is connected to the external negative pressure pipe.

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