Hot air energy-saving furnace

Abstract

The invention discloses a hot air energy-saving furnace which comprises a furnace body and a circulating fan, and a fresh air pipeline, a hot air pipeline and a smoke exhaust pipeline are arranged on the furnace body; a heat exchange box body is mounted in the furnace body, and a fresh air cavity is formed between the furnace body and the heat exchange box body; four transfer chambers are arranged on the outer wall of the heat exchange box body, a heat exchange chamber is arranged in the heat exchange box body, and a hot air cavity is formed between the heat exchange chamber and the box body; the heat exchange chamber comprises a combustion chamber, three smoke chambers, an air chamber and a heat exchange pipe. Smoke sequentially flows through the combustion chamber, the first smoke chamber, the second smoke chamber, smoke pipes in the air chamber and the third smoke chamber and then is exhausted. Fresh air sequentially flows through the fresh air cavity, the circulating fan, the first heat exchange pipe located in the third smoke chamber, the air chamber, the second heat exchange pipes located in the first smoke chamber and the second smoke chamber and the hot air cavity and then is output. Through the multi-stage and partitioned heat exchange structure, stepped deep utilization of smoke heat is achieved, the heat efficiency is remarkably improved, the structure is clear, and ash removal and maintenance are facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hot blast stove, in particular to a hot blast energy-saving stove for drying, heating and other processes. BACKGROUND

[0002] In the fields of agricultural product processing, food drying, industrial heating and the like, hot blast stoves are commonly used heat energy equipment. Traditional hot blast stoves usually directly heat air by burning fuel or perform heat exchange through simple heat exchangers, which has the problems of low thermal efficiency and energy waste. In particular, a large amount of waste heat carried by flue gas is directly discharged, resulting in energy loss.

[0003] In the prior art, in order to improve the thermal efficiency, some improvement schemes have appeared. For example, the comparative document 1 (CN222895486U) discloses a tea drying hot blast stove, which comprises a stove body and S-shaped heat exchange pipes, the heat exchange time is increased by prolonging the flue gas path, and the exhaust port is connected to the fresh air inlet to preheat fresh air by using the waste heat of flue gas. Although this scheme improves the heat utilization rate to a certain extent, the heat exchange structure is relatively simple, the heat exchange between flue gas and fresh air is mainly one-time preheating at the end of flue gas flow (at the exhaust port), and the preheating effect and the multi-stage and deep utilization of overall heat energy still have room for improvement. In addition, the structure of the S-shaped pipe may cause large flue gas flow resistance, and it is inconvenient to clean and maintain.

[0004] Therefore, how to design an energy-saving hot blast stove with a more reasonable heat exchange path, which can realize multi-stage and deep heat exchange and is convenient to maintain, has become a problem to be solved by those skilled in the art. SUMMARY

[0005] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a hot blast energy-saving stove, which significantly prolongs and optimizes the heat exchange path of flue gas and fresh air through a unique multi-stage and zoned heat exchange structure, realizes efficient gradient utilization of heat energy, improves overall thermal efficiency, and is convenient to clean and maintain in structure design.

[0006] To achieve the above purpose, the present application adopts the following technical scheme: A hot blast energy-saving stove comprises a stove body and a circulating fan, the stove body is provided with a fresh air pipeline, a hot air pipeline and an exhaust pipeline, and the key lies in that: A heat exchange box body is installed in the stove body and communicates with the hot air pipeline, and a fresh air cavity is formed between the heat exchange box body and the stove body and communicates with the circulating fan air inlet and the fresh air pipeline respectively; A transfer chamber one, a transfer chamber two, a transfer chamber three and a transfer chamber four are installed on the outer wall of the heat exchange box body; A heat exchange chamber is arranged in the heat exchange box, and the heat exchange chamber and the heat exchange box form a hot air cavity in communication with the hot air pipeline.

[0007] The heat exchange chamber comprises a combustion chamber, a smoke chamber one, a smoke chamber two, a wind chamber, a smoke chamber three, a plurality of heat exchange pipes one and a plurality of heat exchange pipes two.

[0008] The smoke chamber one is in communication with the combustion chamber and the transfer chamber one respectively; the smoke chamber two is in communication with the transfer chamber one and the transfer chamber two respectively; the wind chamber is internally provided with a plurality of smoke pipes one and a plurality of smoke pipes two; the two ends of the smoke pipe one are in communication with the transfer chamber two and the transfer chamber three respectively; the two ends of the smoke pipe two are in communication with the transfer chamber three and the transfer chamber four respectively; the two ends of the smoke chamber three are in communication with the transfer chamber four and the exhaust smoke pipeline respectively; the smoke generated by the fuel in the combustion chamber is exhausted to the outside after sequentially passing through the smoke chamber one, the transfer chamber one, the smoke chamber two, the transfer chamber two, the smoke pipe one, the transfer chamber three, the smoke pipe two, the transfer chamber four, the smoke chamber three and the exhaust smoke pipeline under the suction of the exhaust smoke fan.

[0009] The heat exchange pipe one is arranged in the smoke chamber three, and the two ends thereof are in communication with the circulating fan air outlet and the wind chamber respectively; the two ends of the heat exchange pipe two extend into the smoke chamber one and the smoke chamber two respectively, and the two ends thereof are in communication with the wind chamber and the hot air cavity respectively. Fresh air is exhausted to the outside after sequentially passing through the fresh air pipeline, the fresh air cavity, the circulating fan, the heat exchange pipe one, the wind chamber, the heat exchange pipe two, the hot air cavity and the hot air pipeline under the suction of the circulating fan.

[0010] Further, the exhaust smoke pipeline is provided with the exhaust smoke fan, and the fresh air pipeline is provided with a fresh air fan, and the air flow is accurately controlled through the cooperative work of the fans.

[0011] Further, the combustion chamber is provided with a furnace bridge for ash removal at the bottom.

[0012] Further, the combustion chamber is provided with a screw conveyor for conveying fuel into the combustion chamber, and an igniter for igniting the fuel, so as to realize automatic feeding and ignition.

[0013] Further, the furnace body is provided with three ash removal pipelines with doors, one of which is in communication with the inside bottom of the combustion chamber, one of which is in communication with the transfer chamber two, and one of which is in communication with the transfer chamber four, so as to facilitate the cleaning of the parts prone to ash accumulation.

[0014] Further, a transparent observation window is arranged on the door of the ash removal pipeline in communication with the inside bottom of the combustion chamber, so as to facilitate the observation of the inside of the combustion chamber.

[0015] Further, the outer wall of the smoke chamber one and the smoke chamber two is provided with a plurality of heat exchange plates in the hot air cavity to further strengthen heat exchange.

[0016] Further, the outer wall of the heat exchange pipe one and the heat exchange pipe two is provided with a plurality of heat exchange fins to improve heat exchange efficiency.

[0017] Further, the outer wall of the furnace body and the heat exchange box body is covered with a heat preservation layer to reduce heat loss.

[0018] Further, the lower side wall of the combustion chamber is provided with a plurality of air inlets connected to the outside to provide sufficient oxygen for combustion.

[0019] The beneficial effects of the present application are: (1) Multi-stage deep heat exchange, high thermal efficiency: The present application sets up a complex and orderly heat exchange network by setting up a plurality of independent smoke chambers (smoke chamber one, two and three), air chambers and heat exchange pipes one, two and smoke pipes one and two distributed therebetween. Fresh air is first preheated by absorbing the waste heat of low-temperature flue gas in the smoke chamber three through the heat exchange pipe one; then enters the air chamber; then is deeply heated by absorbing the heat of high-temperature flue gas through the heat exchange pipe two extending into the smoke chamber one and the smoke chamber two through which the high-temperature flue gas flows; and finally is finally heated in the hot air cavity. Flue gas flows through the high-temperature zone and the medium-temperature zone in turn, and finally releases the remaining heat to the fresh air in the smoke chamber three. The whole process realizes multi-stage and gradient utilization of heat energy, significantly improving the heat recovery efficiency.

[0020] (2) Clear structure partition, easy to maintain: The heat exchange system is integrated in the heat exchange box body, and clear fresh air cavity and hot air cavity are formed between the heat exchange box body and the furnace body, and the airflow organization is clear. The setting of a plurality of transfer chambers and independent ash removal pipelines makes it easy to clean the parts where dust easily deposits (such as the bottom of the combustion chamber, the second and fourth transfer chambers), reducing the difficulty of maintenance.

[0021] The present application adopts a structure of multi-chamber separation and multi-pipeline penetration, which not only greatly prolongs the effective heat exchange path, but also realizes more precise and complete utilization of flue gas heat through the process design of "low-temperature preheating - medium-temperature heating - final heating", and the energy saving effect is more optimal. At the same time, the modular box body and transfer chamber design also has more flexibility in manufacturing and assembly. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a perspective view of the hot air energy-saving stove according to the present application.

[0023] Figure 2 It is a front view of the hot air energy-saving stove according to the present application.

[0024] Figure 3 It is a full cross-sectional view of Figure 2 .

[0025] Figure 4 For Figure 2 Fig. 2 is a sectional view along the direction of A-A.

[0026] Fig. 1: 1 - furnace body; 2 - circulating fan; 3 - fresh air duct; 31 - fresh air fan; 4 - hot air duct; 5 - exhaust duct; 51 - exhaust fan; 6 - heat exchange box; 7 - fresh air cavity; 81 - transfer chamber 1; 82 - transfer chamber 2; 83 - transfer chamber 3; 84 - transfer chamber 4; 9 - hot air cavity; 10 - combustion chamber; 111 - smoke chamber 1; 112 - smoke chamber 2; 113 - smoke chamber 3; 12 - air chamber; 121 - smoke pipe 1; 122 - smoke pipe 2; 13 - heat exchange pipe 1; 14 - heat exchange pipe 2; 15 - furnace bridge; 16 - screw conveyor; 17 - ash removal duct; 18 - observation window; 19 - air inlet; 20 - heat exchange plate; 21 - fuel bin. DETAILED DESCRIPTION

[0027] The embodiments of the present application will be described herein below with reference to specific embodiments. Those skilled in the art will readily understand other advantages and functions of the present application after reading the description of the embodiments. The described embodiments are only a part of the embodiments of the present application, and are not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0028] It should be understood that the structures, proportions, sizes, etc. shown in the drawings of the present specification are only used to cooperate with the content disclosed in the present specification, to enable those skilled in the art to understand and read, and are not used to limit the conditions for implementing the present application, and therefore do not have technical significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects and purposes that can be achieved by the present application, should still fall within the scope of the technology disclosed by the present application. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and the like used in the present specification are only for the convenience of clear description, and are not used to limit the scope of the present application, and the change or adjustment of the relative relationship without substantially changing the technical content should also be considered as the scope of the present application.

[0029] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. It should be noted that the terms "include", "contain" or any other variant are intended to cover non-exclusive inclusion, so that the process, method, article or equipment containing a series of elements not only includes those elements, but also includes other elements not explicitly listed, or includes elements inherent to such process, method, article or equipment. Embodiment 1

[0030] As Figures 1 to 4 shown, the present application provides a hot air energy-saving stove, comprising a stove body 1 and a circulating fan 2.

[0031] The stove body 1 is a closed shell formed by welding a heat-resistant steel plate, the top four corners of which are provided with lifting lugs for easy lifting, and the bottom four corners are provided with supporting feet, and if necessary, rollers can be installed on the supporting feet to facilitate movement; on the outer side wall of the stove body 1, a fresh air duct 3 for feeding fresh air, a hot air duct 4 for discharging hot air, and a smoke exhaust duct 5 for discharging smoke are installed.

[0032] In order to achieve efficient and orderly heat exchange, a separate heat exchange box 6 is fixedly installed inside the stove body 1, which is connected to the inner wall of the stove body 1 through a support structure, and the upper part or side part thereof is in communication with the hot air duct 4. A certain distance is maintained between the outer wall of the heat exchange box 6 and the inner wall of the stove body 1, thereby forming a fresh air cavity 7 between the two. One end of the fresh air cavity 7 is in communication with the air inlet of the circulating fan 2, and the other end is in communication with the fresh air duct 3. External normal temperature air (fresh air) or air with residual heat can enter the fresh air cavity 7 through the fresh air duct 3.

[0033] In order to further organize the flow of flue gas and distribute heat, four independent transfer containers are fixedly installed in sequence on the outer side wall of the heat exchange box 6: transfer chamber one 81, transfer chamber two 82, transfer chamber three 83 and transfer chamber four 84. These transfer chambers are usually box-shaped structures and are in communication with the corresponding chambers inside the heat exchange box 6 through connecting pipes or openings.

[0034] The inside of the heat exchange box 6 is the core heat exchange area. The inside is separated by a partition to form a heat exchange chamber, and the outer wall of the heat exchange chamber and the inner wall of the heat exchange box 6 form a hot air cavity 9. The hot air cavity 9 is in communication with the hot air duct 4, and the finally heated hot air is collected and output.

[0035] The heat exchange chamber comprises a combustion chamber 10, a flue chamber 11, an air chamber 12, a plurality of heat exchange pipes I 13 and a plurality of heat exchange pipes II 14.

[0036] The combustion chamber 10 is located at the lower part or one end of the heat exchange box 6, which is the place where high-temperature flue gas is generated by burning fuel (such as biomass particles, coal, etc.), and its flue gas outlet is at the top. The lower side wall of the combustion chamber 10 is provided with a plurality of air inlets 19 connected to the outside, providing sufficient oxygen for combustion.

[0037] The flue chamber 11 comprises three independent box-shaped structures or cylinder structures, which are flue chamber I 111, flue chamber II 112 and flue chamber III 113 arranged vertically and side by side.

[0038] The lower end of the flue chamber I 111 is in communication with the flue gas outlet of the combustion chamber 10, and the upper end is in communication with the transfer chamber I 81.

[0039] The lower end of the flue chamber II 112 is in communication with the transfer chamber I 81, and the upper end is in communication with the transfer chamber II 82.

[0040] The lower end of the flue chamber III 113 is in communication with the transfer chamber IV 84, and the upper end is in communication with the flue gas duct 5.

[0041] The air chamber 12 is also a relatively independent chamber arranged between the flue chamber II 112 and the flue chamber III 113, and a plurality of parallel flue pipes I 121 and a plurality of parallel flue pipes II 122 are vertically arranged inside. One end of all flue pipes I 121 is in communication with the transfer chamber II 82, and the other end is in communication with the transfer chamber III 83. One end of all flue pipes II 122 is in communication with the transfer chamber III 83, and the other end is in communication with the transfer chamber IV 84.

[0042] The heat exchange pipe I 13 is a plurality of pipe bodies arranged transversely in the internal space of the flue chamber III 113. Their inlet ends are in common communication with the air outlet of the circulating fan 2, and their outlet ends commonly extend into and communicate with the internal space of the air chamber 12.

[0043] The heat exchange pipe II 14 is a plurality of pipe bodies arranged transversely, which penetrate the partition plate between the flue chamber I 111 and the flue chamber II 112, so that their two ends extend into the flue chamber I 111 and the flue chamber II 112 respectively. The inlet ends of all heat exchange pipes II 14 are in communication with the internal space of the air chamber 12, and the outlet ends of all heat exchange pipes II 14 are in common communication with the hot air cavity 9. Brief working principle:

[0044] Flue gas path: the high-temperature flue gas generated by the combustion chamber 10 flows through the smoke chamber 1 111, the transfer chamber 1 81, the smoke chamber 2 112, the transfer chamber 2 82, the smoke pipe 1 121, the transfer chamber 3 83, the smoke pipe 2 122, the transfer chamber 4 84, the smoke chamber 3 113, and finally is discharged from the flue gas discharge pipeline 5. In this process, the flue gas heat is extracted step by step.

[0045] Air path: the outside fresh air enters the fresh air cavity 7 through the fresh air pipeline 3, is sucked into and pumped into the heat exchange pipe 1 13 by the circulating fan 2, is preheated by the low-temperature flue gas in the smoke chamber 3 113 for the first time. The preheated air enters the air chamber 12, is further heated by the smoke pipe 1 121 and the smoke pipe 2 122, and then flows into the heat exchange pipe 2 14 to exchange heat with the high-temperature flue gas in the smoke chamber 1 111 and the smoke chamber 2 112, so that the fresh air is quickly and deeply heated (high-temperature heating). The heated hot air enters the hot air cavity 9 to collect, and in the hot air cavity 9, the hot air further absorbs heat transferred from the outer walls of the smoke chamber 1 111 and the smoke chamber 2 112, and performs the final temperature balancing and rising. At the same time, the hot air cavity 9 also serves as a collection cavity for the hot air. The hot air finally reaches the required temperature and is delivered to the heat-using equipment through the hot air pipeline 4. Example 2

[0046] On the basis of example 1, in order to further accurately control and ensure the air flow intensity, a driving fan is added in this example. Specifically, a flue gas fan 51 is installed on the flue gas discharge pipeline 5 to actively suck the flue gas and ensure the smooth flow of the flue gas in the complex heat exchange path. A fresh air fan 31 can be installed on the fresh air pipeline 3 to assist in adjusting the fresh air intake. The fans work together to accurately control the furnace pressure and air volume. Example 3

[0047] On the basis of example 1 or 2, in order to facilitate maintenance, a dust removal and observation structure is added in this example. Three dust removal pipelines 17 with sealed doors are provided on the furnace body 1 and are in communication with the inner bottom of the combustion chamber 10, the transfer chamber 2 82 and the transfer chamber 4 84 respectively, for cleaning the deposited ash. Preferably, a heat-resistant transparent observation window 18 is provided on the sealed door of the dust removal pipeline 17 in communication with the combustion chamber 10, so as to observe the flame state in the combustion chamber in real time. In addition, a furnace bridge 15 can be provided at the bottom of the combustion chamber 10 to facilitate the falling and cleaning of the ash. By periodically opening the sealed doors of the corresponding dust removal pipelines 17, the furnace ash of the combustion chamber 10 and the transfer chamber 2 82 and the transfer chamber 4 84 which are prone to ash deposition can be cleaned, to ensure the smoothness of the flue and the heat exchange efficiency. Example 4

[0048] On the basis of any one of the above embodiments, in order to realize automatic operation, the combustion chamber 10 of the present embodiment is connected with a screw conveyor 16 for quantitatively and continuously conveying the fuel (such as biomass particles) in the fuel bin 21 into the combustion chamber 10. At the same time, a igniter (commonly used for conventional hot blast stove) is arranged in the combustion chamber 10 or at the entrance thereof for automatically igniting the fuel. A fuel bin 21 for storing solid fuel is arranged outside the furnace body 1, and one end of the screw conveyor 16 extends into the fuel bin 21 and the other end extends into the combustion chamber 10. Embodiment 5

[0049] On the basis of any one of the above embodiments, in order to significantly increase the heat exchange area and improve the heat exchange efficiency, the present embodiment is designed as follows: A plurality of heat exchange plates 20 extending into the hot air cavity 9 are welded on the outer walls of the smoke chamber one 111 and the smoke chamber two 112. Dense heat exchange fins are sleeved or welded on the outer walls of the heat exchange pipe one 13 and the heat exchange pipe two 14. The heat exchange plates 20 and the heat exchange fins can effectively enhance the heat exchange strength between the flue gas and the air. Embodiment 6

[0050] On the basis of any one of the above embodiments, in order to reduce the heat loss of the furnace body and improve the overall thermal efficiency, the present embodiment coats a heat preservation layer (such as rock wool, aluminum silicate fiber blanket, etc.) on the outer walls of the furnace body 1 and the heat exchange box 6.

[0051] In summary, the present application realizes multi-stage, echelon and depth recycling of flue gas heat from high to low through the flue gas path design of “combustion chamber → multi-stage smoke chamber → multi-pass smoke pipe”, and efficiently transfers the heat to the fresh air through the fresh air heating path design of “fresh air cavity → low-temperature preheating (heat exchange pipe one) → air chamber heating (further heating) → high-temperature heating (heat exchange pipe two) → final heating (hot air cavity)”, thereby significantly improving the heat energy utilization rate. The modular and partitioned structure also makes manufacturing and maintenance more convenient.

[0052] The other details of the present application are well known to those skilled in the art.

[0053] It should be noted that the terms “include”, “contain” or any other variant are intended to cover non-exclusive inclusion, so that the process, method, article or equipment containing a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment.

[0054] The protection scope of the present application is not limited to the technical solutions disclosed in the specific embodiments, and any modification, equivalent replacement, improvement, etc. made according to the technical essence of the present application to the above embodiments all fall within the protection scope of the present application.

Claims

1. A hot air energy-saving furnace, comprising a furnace body (1) and a circulating fan (2), wherein the furnace body (1) is equipped with a fresh air duct (3), a hot air duct (4), and a smoke exhaust duct (5), characterized in that: The furnace body (1) is equipped with a heat exchange box (6) that is connected to the hot air pipe (4), and a fresh air cavity (7) is formed between the heat exchange box (6) and the furnace body (1) respectively connected to the air inlet of the circulating fan (2) and the fresh air pipe (3). Transfer chamber one (81), transfer chamber two (82), transfer chamber three (83) and transfer chamber four (84) are installed on the outer side wall of the heat exchange box (6); A heat exchange chamber is provided inside the heat exchange box (6), and a hot air cavity (9) is formed between the heat exchange chamber and the heat exchange box (6) and is connected to the hot air duct (4); the heat exchange chamber includes a combustion chamber (10), a smoke chamber one (111), a smoke chamber two (112), a wind chamber (12), a smoke chamber three (113), a number of heat exchange tubes one (13) and a number of heat exchange tubes two (14); The first smoke chamber (111) is connected to the combustion chamber (10) and the first transfer chamber (81); the second smoke chamber (112) is connected to the first transfer chamber (81) and the second transfer chamber (82); the air chamber (12) is provided with a plurality of first smoke pipes (121) and a plurality of second smoke pipes (122); the two ends of the first smoke pipe (121) are connected to the second transfer chamber (82) and the third transfer chamber (83) respectively; the two ends of the second smoke pipe (122) are connected to the third transfer chamber (83) and the fourth transfer chamber (84) respectively; the two ends of the third smoke chamber (113) are connected to the fourth transfer chamber (84) and the exhaust pipe (5) respectively. The first heat exchange tube (13) is located in the third smoke chamber (113), and its two ends are connected to the air outlet of the circulating fan (2) and the air chamber (12), respectively; the two ends of the second heat exchange tube (14) extend into the first smoke chamber (111) and the second smoke chamber (112), respectively, and its two ends are connected to the ventilation chamber (12) and the hot air cavity (9), respectively.

2. The hot air energy-saving furnace according to claim 1, characterized in that: A smoke exhaust fan (51) is installed on the smoke exhaust duct (5), and a fresh air fan (31) is installed on the fresh air duct (3).

3. The hot air energy-saving furnace according to claim 1, characterized in that: The bottom of the combustion chamber (10) is provided with a furnace bridge (15) for ash removal.

4. A hot air energy-saving furnace according to claim 1, characterized in that: The combustion chamber (10) is fed fuel into it by a screw conveyor (16) and ignited by an igniter.

5. A hot air energy-saving furnace according to claim 1, characterized in that: The furnace body (1) is provided with three ash removal pipes (18) with doors, one of which is connected to the bottom of the inner side of the combustion chamber (10), one is connected to the second transfer chamber (82), and one is connected to the fourth transfer chamber (84).

6. A hot air energy-saving furnace according to claim 1, characterized in that: The furnace body (1) is provided with three ash removal pipes (17) with doors, one of which is connected to the bottom of the inner side of the combustion chamber (10), one is connected to the second transfer chamber (82), and one is connected to the fourth transfer chamber (84).

7. A hot air energy-saving furnace according to claim 1, characterized in that: A transparent observation window (18) is provided on the door of the ash removal pipe (17) which is connected to the bottom of the inner side of the combustion chamber (10).

8. A hot air energy-saving furnace according to claim 1, characterized in that: The outer walls of the smoke chamber 1 (111) and smoke chamber 2 (112) are provided with a number of heat exchange plates (20) located in the hot air cavity (9).

9. A hot air energy-saving furnace according to claim 1, characterized in that: Both heat exchange tube one (13) and heat exchange tube two (14) have a number of heat exchange fins on their outer walls.

10. A hot air energy-saving furnace according to claim 1, characterized in that: The outer walls of both the furnace body (1) and the heat exchange box (6) are covered with an insulation layer.

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