Air duct structure and hot air circulation drying equipment applying same

Abstract

The utility model discloses an air duct structure, and discloses hot air circulation drying equipment with the air duct structure, and the air duct structure comprises an air outlet cavity defined in a shell; the partition plate is annularly arranged in the shell and divides the air cavity into an outer air duct and an inner air duct, the outer air duct surrounds the inner air duct in a closed loop shape, an air inlet and an air outlet are formed in the partition plate, air in the outer air duct can be conveyed to the inner air duct through the air inlet, and air in the inner air duct can be conveyed to the outer air duct through the air outlet; through the cooperation of the outer air duct and the inner air duct, hot air flows orderly and circularly, and the whole shell can be heated uniformly; hot air discharged out of the shell before heat exchange can be reduced, a certain energy and heat gathering effect is achieved, heat loss is effectively reduced, energy consumption is reduced, and the heat exchange effect with the outside through the shell is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of heating equipment, in particular to an air duct structure and hot air circulation drying equipment using the same. Background Art

[0002] Some existing heating devices, such as dryers and heaters, heat items by blowing out hot air. These devices generally release the hot air directly into the environment through a fan, and use the hot air to heat and dry the items. This heating and drying method causes the heat to dissipate very quickly, resulting in high energy consumption and low thermal energy utilization. Utility Model Content

[0003] The utility model aims to solve one of the above-mentioned technical problems in the related art at least to a certain extent. To this end, the utility model proposes an air duct structure.

[0004] To achieve the above purpose, the technical solution of the utility model is as follows:

[0005] The utility model also provides a hot air circulation drying device with the air duct structure.

[0006] According to the first aspect of the present invention, the air duct structure of the embodiment includes:

[0007] A housing, wherein an air outlet cavity is defined inside the housing;

[0008] A partition is arranged in a ring shape inside the shell, and the partition divides the wind cavity into an outer air duct and an inner air duct. The outer air duct surrounds the inner air duct in a closed loop. An air inlet and an exhaust port are provided on the partition. The air inlet can transport the gas in the outer air duct to the inner air duct, and the exhaust port can transport the gas in the inner air duct to the outer air duct.

[0009] According to the air duct structure of the embodiment of the utility model, at least the following beneficial effects are achieved: the cooperation between the outer air duct and the inner air duct allows the hot air to circulate in an orderly manner, so that the shell as a whole can be heated evenly; it can reduce the discharge of hot air outside the shell before completing the heat exchange, thus achieving a certain energy and heat gathering effect, effectively reducing heat loss, reducing energy consumption, and ensuring the heat exchange effect between the shell and the outside world.

[0010] According to some embodiments of the present invention, the opening size at the exhaust port is larger than the opening size at the air inlet.

[0011] According to some embodiments of the present utility model, the partition includes a first arc-shaped portion, a second arc-shaped portion, a first connecting portion and a second connecting portion, the inner arc surface of the first arc-shaped portion is opposite to the inner arc surface of the second arc-shaped portion, and the first connecting portion and the second connecting portion are respectively connected between the opposite ends of the first arc-shaped portion and the second arc-shaped portion.

[0012] According to some embodiments of the present invention, the opening directions of the air inlet and the air outlet are consistent with the flow direction of the gas in the external air duct along the partition.

[0013] According to some embodiments of the present invention, the first connecting portion is extended from the end of the first arc-shaped portion toward the second arc-shaped portion, and an arc-shaped interval is formed between the end of the first connecting portion and the end of the second arc-shaped portion to form the air inlet, and the air inlet is tangent to the outer arc surface of the second arc-shaped portion;

[0014] The second connection portion is extended from the end of the second arc-shaped portion toward the first arc-shaped portion, and an arc-shaped interval is formed between the end of the second connection portion and the end of the first arc-shaped portion to form the exhaust port, and the exhaust port is tangent to the outer arc surface of the first arc-shaped portion.

[0015] According to the second aspect of the embodiment of the utility model, the hot air circulation drying equipment includes: a hot air generating mechanism, a first fan and an air duct structure, the first fan and the hot air generating mechanism are both installed in the external air duct, the hot air generating mechanism is used to heat the airflow in the air cavity, and the first fan is used to increase the airflow speed of the external air duct.

[0016] The hot air circulation drying device according to the embodiment of the utility model has at least the following beneficial effects: the application of the air duct structure enables the device to effectively utilize the thermal energy in the hot air, with low overall energy consumption and high drying efficiency.

[0017] According to some embodiments of the utility model, the external air duct is runway-shaped, the air inlet and the exhaust port are both arranged at the turning positions on both sides of the partition, the first fan is installed close to the exhaust port, and the hot air generating mechanism is installed close to the air inlet.

[0018] According to some embodiments of the utility model, the hot air generating mechanism includes an outer cylinder, an electric heating element and a second fan, the outer cylinder is provided with an air inlet end and an air outlet end, the second fan and the electric heating element are installed in the outer cylinder, the airflow in the external air duct enters the outer cylinder through the air inlet end and flows out from the air outlet end, and the rotation speed of the first fan is greater than the rotation speed of the second fan.

[0019] According to some embodiments of the utility model, a pressure relief port and an air inlet are provided on the shell, and both the pressure relief port and the air inlet can connect the wind cavity to the outside of the shell, and a pressure relief valve is installed at the pressure relief port, and the pressure relief valve controls the gas inside the wind cavity to be discharged to the outside of the shell after reaching a preset pressure, and an air intake valve is provided at the air inlet, and the air intake valve controls the gas outside the shell to flow unidirectionally to the wind cavity.

[0020] According to some embodiments of the utility model, sound-absorbing cotton is installed in the inner air duct.

[0021] According to some embodiments of the present invention, a temperature sensor is installed on the partition.

[0022] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0024] Figure 1 It is a schematic diagram of the internal structure of the air duct structure;

[0025] Figure 2 It is a schematic diagram of the structural decomposition of the hot air circulation drying equipment;

[0026] Figure 3 It is a schematic diagram of the internal structure of the hot air circulation drying equipment;

[0027] Figure 4 yes Figure 3 A magnified schematic diagram of the local structure.

[0028] Figure numerals: shell 100; wind cavity 110; external air duct 111; internal air duct 112; pressure relief port 120; air inlet 130; partition 200; air inlet 201; air outlet 202; first arc-shaped portion 210; second arc-shaped portion 220; first connecting portion 230; second connecting portion 240; hot air generating mechanism 300; outer cylinder 310; air inlet end 311; air outlet end 312; electric heating element 320; second fan 330; first fan 400; pressure relief valve 500; air inlet valve 600; silencer cotton 700; temperature sensor 800. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0030] The utility model relates to an air duct structure, which mainly circulates and transports gas, so as to fully use the heat energy inside the gas. The air duct structure can be used in conjunction with an external hot air system, or a related hot air device can be installed inside the air duct structure for use.

[0031] Reference Figure 1, the outer contour of the shell 100 can be in the shape of a rectangular box, but is not limited thereto. For example, the shell 100 can also be in the shape of a disc. The shell 100 can be spliced ​​by two opposite half shells, or the shell 100 can be composed of a base and a cover. The interior of the shell 100 defines a cavity, which is defined as a wind cavity 110. A partition 200 is provided inside the shell 100. The partition 200 is annular. The annular shape of the partition 200 can be a circular ring, an elliptical shape, a runway shape, etc. The partition 200 separates the wind cavity 110 into an outer air duct 111 and an inner air duct 112. The space between the inner wall of the shell 100 and the outer side wall of the partition 200 constitutes the outer air duct 111, and the space surrounded by the partition 200 constitutes the inner air duct 112. In terms of space, the outer air duct 111 is in a closed loop, and the outer air duct 111 surrounds the inner air duct 112. An air inlet 201 and an exhaust port 202 are provided on the partition 200. Both the air inlet 201 and the exhaust port 202 can connect the outer air duct 111 and the inner air duct 112. Among them, the air inlet 201 is used to transport the gas in the outer air duct 111 to the inner air duct 112, and the exhaust port 202 is used to transport the gas in the inner air duct 112 to the outer air duct 111. In actual use, the external hot air system or the hot air device built into the shell 100 forms a hot air flow in the outer air duct 111, and the air flow circulates along the outer air duct 111. During the flow, part of the air flow will enter the inner air duct 112 from the air inlet, and the hot air will fill the inner air duct 112, and then flow back to the outer air duct 111 from the exhaust port 202, so as to realize the circulation of gas in the outer air duct 111 and between the outer air duct 111 and the inner air duct 112. During the circulation process, the heat energy in the gas is exchanged with the external environment through the shell 100. The heat energy heats the objects placed on the surface of the shell 100 or near the shell 100, and plays the role of drying, heat preservation and other functions. With the cooperation of the outer air duct 111 and the inner air duct 112, the hot air flow circulates in the shell 100 in an orderly manner, which can make the shell 100 evenly heated as a whole, avoiding the problem of local excessive temperature; in addition, during the gas circulation process, the wind cavity 110 of the shell 100 is equivalent to a sealed cavity, which can reduce the hot air from being discharged to the outside of the shell 100 before the heat exchange is completed, and play a certain energy and heat gathering effect, effectively reduce heat loss, reduce energy consumption, and ensure the heat exchange effect with the outside through the shell 100. The first fan 400 and the hot air generating mechanism 300 are installed in the shell 100. The shell 100 also has a protective effect on the first fan 400 and the hot air generating mechanism 300, and can also play a certain dustproof and waterproof role to ensure the safety of use.

[0032] Based on the above structure, one-way valves corresponding to the gas flow direction can be installed in the air inlet 201 and the air outlet 202. In order to ensure the gas flow between the outer air duct 111 and the inner air duct 112, in actual use, a fan can be installed in the inner air duct 112 to draw the airflow in the outer air duct 111 into the inner air duct 112, accelerate the gas flow in the inner air duct 112, and then flow back to the outer air duct 111 from the exhaust port 202 after flowing through the inner air duct 112. It can also be set that the opening size of the exhaust port 202 is larger than the opening size of the air inlet 201. When the airflow flows through the exhaust port 202 and the air inlet 201 in the outer air duct 111, there is a difference in the opening size of the exhaust port 202 and the air inlet 201, and the gas forms a torrent when it flows near the air inlet 201, so that the gas has enough power to rush into the inner air duct 112 from the air inlet 201. Compared to the gas flow at the air inlet 201 , the larger opening of the exhaust port 202 allows the air flow to flow out slowly.

[0033] The air inlet 201 and the air outlet 202 may be formed by directly setting an opening on the partition 200, or by extending a convex structure on the partition 200 to form the air inlet 201 and the air outlet 202. The forming method of the air inlet 201 and the air outlet 202 is not limited.

[0034] In some embodiments, reference Figure 1 , the partition 200 includes a first arc-shaped portion 210, a second arc-shaped portion 220, a first connecting portion 230 and a second connecting portion 240. The first arc-shaped portion 210 has two side surfaces, the surface facing the arc center direction is the inner arc surface, and the surface away from the arc center is the outer arc surface, and the second arc-shaped portion 220 is the same. The inner arc surface of the first arc-shaped portion 210 is opposite to the inner arc surface of the second arc-shaped portion 220. The opposite ends of the first arc-shaped portion 210 and the second arc-shaped portion 220 are connected by the first connecting portion 230, and the other opposite ends of the first arc-shaped portion 210 and the second arc-shaped portion 220 are connected by the second connecting portion 240. The first connecting portion 230 and the second connecting portion 240 can be in the shape of a straight plate, and the first connecting portion 230 and the second connecting portion 240 are parallel to each other. The space enclosed by the first arc-shaped portion 210, the second arc-shaped portion 220, the first connecting portion 230 and the second connecting portion 240 constitutes the inner air duct 112. The outer air duct 111 is in the shape of a runway as a whole. The first connection portion 230 and the second connection portion 240 may also be in an arc shape, a wave shape, or the like.

[0035] The air inlet 201 and the air outlet 202 may be provided at any position of the first arc-shaped portion 210, the second arc-shaped portion 220, the first connecting portion 230, and the second connecting portion 240. Figure 1, in the direction shown in the figure, the first arc portion 210 and the second arc portion 220 are distributed left and right, the first connection portion 230 and the second connection portion 240 are distributed up and down, and the airflow flows in the outer air duct 111 along the partition 200 in a counterclockwise direction. Among them, the opening direction of the air inlet 201 and the exhaust port 202 is consistent with the flow direction of the gas in the outer air duct 111 along the partition 200. For example, if the air inlet 201 or the exhaust port 202 is set at the first connection portion 230, the opening direction of the air inlet 201 or the exhaust port 202 is from right to left; if the air inlet 201 or the exhaust port 202 is set at the first arc portion 210, the opening direction of the air inlet 201 or the exhaust port 202 is tangent to the first arc portion 210 from bottom to top. The opening direction of the air inlet 201 or the exhaust port 202 can prevent the airflow from colliding with the air inlet 201 or the exhaust port 202 when flowing in the external air duct 111, thereby reducing the gas noise at the air inlet 201 or the exhaust port 202.

[0036] Specifically, refer to Figure 1 , in the direction shown in the figure, the first connecting portion 230 is extended from the upper end of the first arc-shaped portion 210 toward the second arc-shaped portion 220. The first connecting portion 230 can be set to extend linearly until it extends to the upper end close to the second arc-shaped portion 220, and the left end of the first connecting portion 230 makes a downward arc turn along the arc direction of the second arc-shaped portion 220. An arc-shaped interval is formed between the left end of the first connecting portion 230 and the upper end of the second arc-shaped portion 220, and the interval forms the air inlet 201. Spatially, the air inlet 201 is tangent to the outer arc surface of the second arc-shaped portion 220. By setting the interval width between the first connecting portion 230 and the second arc-shaped portion 220, the opening setting size of the air inlet 201 can be controlled. The second connecting portion 240 is extended from the lower end of the second arc-shaped portion 220 toward the first arc-shaped portion 210. The second connecting portion 240 can be arranged to extend linearly until it extends close to the lower end of the first arc-shaped portion 210, and the right end of the second connecting portion 240 turns upward in an arc shape along the arc direction of the first arc-shaped portion 210. An arc-shaped interval is formed between the right end of the second connecting portion 240 and the lower end of the first arc-shaped portion 210, and the interval forms the exhaust port 202. The exhaust port 202 is tangent to the outer arc surface of the first arc-shaped portion 210. By setting the width of the interval between the second connecting portion 240 and the first arc-shaped portion 210, the opening setting size of the air inlet 201 can be controlled.

[0037] The utility model also relates to a hot air circulation drying device. The hot air circulation drying device is one of the application modes of the above-mentioned air duct structure, and its hot air flow is directly formed inside the air duct structure. Figure 2 and Figure 3The hot air circulation drying equipment includes a hot air generating mechanism 300, a first fan 400 and an air duct structure. The first fan 400 and the hot air generating mechanism 300 are both installed in the outer air duct 111. The hot air generating mechanism 300 can heat the gas in the wind cavity 110 by electric heating. The first fan 400 is started in the outer air duct 111 to accelerate the flow speed of the air flow in the outer air duct 111. With the cooperation of the air inlet 201 and the exhaust port 202, the air flow will also circulate in the outer air duct 111 and the inner air duct 112. When the air flow flows in the outer air duct 111, it is heated by the hot air generating mechanism 300 to directly form hot air inside the shell 100. The air flow circulates continuously in the outer air duct 111 and the inner air duct 112. Heat is exchanged with the outside world through the shell 100. Articles such as towels and clothes are placed on the shell 100. The shell 100 serves as a carrier to heat and dry the articles, effectively utilizing the thermal energy in the hot air, with low overall energy consumption and high drying efficiency.

[0038] In some specific embodiments of the present invention, refer to Figure 3 , the outer air duct 111 is in the shape of a runway. In the direction shown in the figure, the left and right sides of the outer air duct 111 are curved, and the upper and lower sides are straight. The air inlet 201 and the exhaust port 202 are both arranged at the turning positions on both sides of the partition 200, that is, corresponding to the transition position of the curve and the straight in the outer air duct 111. The first fan 400 is installed close to the exhaust port 202, and the hot air generating mechanism 300 is installed close to the air inlet. The first fan 400 forms a high-speed airflow near the exhaust port 202, and the flow rate is greater than the airflow at the air inlet 201, so that a pressure difference is formed between the exhaust port 202 and the air inlet 201. The space near the air inlet 201 in the outer air duct 111 forms a high-pressure area, and the space near the exhaust port 202 forms a low-pressure area. The low-pressure area draws the gas in the inner air duct 112 into the outer air duct 111 through the exhaust port 202, and the high-pressure area draws the gas in the outer air duct 111 into the inner air duct 112 through the air inlet 201, thereby realizing automatic circulation of gas between the inner air duct 112 and the outer air duct 111, and allowing the gas to gradually fill the inner air duct 112, thereby ensuring the heat exchange and drying effect of the shell 100 at the corresponding position of the inner air duct 112.

[0039] Based on the above structure, refer to Figure 2 and Figure 3The hot air generating mechanism 300 includes an outer cylinder 310, an electric heating element 320 and a second fan 330. The outer cylinder 310 is cylindrical, hollow inside and open at both ends. The two ends of the outer cylinder 310 are respectively defined as an air inlet end 311 and an air outlet end 312. The outer cylinder 310 is located in the outer air duct 111, and according to the flow direction of the air flow, the air inlet end 311 is located on the upstream side of the air outlet end 312. When the air flow flows in the outer air duct 111, the air flow enters the outer cylinder 310 through the air inlet end 311, and then is discharged from the air outlet end 312. The second fan 330 and the electric heating element 320 are installed in the outer cylinder 310. As a carrier of the electric heating element 320, the outer cylinder 310 can separate and protect the electric heating element 320 from the shell 100. The second fan 330 can be installed at the air inlet end 311, and the airflow in the outer air duct 111 is drawn into the outer cylinder 310 by the second fan 330, and the air is heated by the electric heating element 320. The rotation speed of the first fan 400 is greater than the rotation speed of the second fan 330, so that the air at the exhaust port 202 and the air inlet 201 have a flow rate difference, and according to the principle of fluid mechanics, the formation of the above-mentioned low-pressure area and high-pressure area is ensured, so as to achieve airflow circulation between the outer air duct 111 and the inner air duct 112.

[0040] In some embodiments of the present invention, referring to Figure 3 and Figure 4 , a pressure relief port 120 and an air inlet 130 are provided on the shell 100. Both the pressure relief port 120 and the air inlet 130 can connect the air cavity 110 to the outside of the shell 100. A pressure relief valve 500 is installed at the pressure relief port 120. When the gas inside the shell 100 is heated, the gas will expand. The expansion of the gas will increase the air pressure in the air cavity 110. If the air pressure reaches or exceeds the preset pressure of the pressure relief valve 500, the pressure relief valve 500 will automatically open, and the gas in the air cavity 110 will be discharged to the outside of the shell 100 through the pressure relief port 120, thereby achieving automatic pressure relief. The pressure relief valve 500 can control the preset pressure through an elastic valve body. An air inlet valve 600 is provided at the air inlet 130. After the heat energy in the gas is released to the external environment through the housing 100, the gas cools down and contracts, and a negative pressure is formed inside the air cavity 110. When the negative pressure reaches the preset pressure of the air inlet valve 600, the air inlet valve 600 opens, and the gas outside the housing 100 flows into the air cavity 110 through the air inlet 130. The air inlet valve 600 can be a one-way valve, and the balance between the gravity of the valve plate of the one-way valve and the air pressure in the air cavity 110 is used to control the opening and closing of the valve plate. Through the cooperation of the pressure relief valve 500 and the air inlet valve 600, effective constant pressure protection is performed on the inside of the housing 100.

[0041] Among them, refer to Figure 4 , a sound-absorbing cotton 700 is installed in the inner air duct 112. The sound-absorbing cotton is used to reduce the noise generated when the air flows through the inner air duct 112. It can also slow down the air flow in the inner air duct 112 to ensure that the gas fills the inner air cylinder. In addition, the sound-absorbing cotton also has a certain heat storage effect.

[0042] In some embodiments of the utility model, a temperature sensor 800 is installed on the partition 200. The temperature sensor 800 is used to detect the gas temperature inside the air cavity 110. A control panel can be installed on the housing 100, and the first motor, the temperature sensor 800, and the hot air generating mechanism 300 are electrically connected to the control panel, and the control panel is used to control the start and stop of each electrical component.

[0043] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0044] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0045] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0047] In the description of this specification, the description of reference terms such as "some specific embodiments" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0048] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An air duct structure, characterized in that: include: A housing (100), wherein an air outlet cavity (110) is defined inside the housing (100); A partition (200), the partition (200) being arranged in an annular shape inside the shell (100), the partition (200) dividing the air cavity (110) into an outer air duct (111) and an inner air duct (112), the outer air duct (111) surrounding the inner air duct (112) in a closed loop, an air inlet (201) and an air outlet (202) being provided on the partition (200), the air inlet (201) being capable of conveying gas from the outer air duct (111) to the inner air duct (112), and the air outlet (202) being capable of conveying gas from the inner air duct (112) to the outer air duct (111).

2. The air duct structure according to claim 1, characterized in that: The opening size at the exhaust port (202) is larger than the opening size at the air inlet (201).

3. The air duct structure according to claim 1 or 2, characterized in that: The partition (200) includes a first arc-shaped portion (210), a second arc-shaped portion (220), a first connecting portion (230) and a second connecting portion (240), wherein the inner arc surface of the first arc-shaped portion (210) and the inner arc surface of the second arc-shaped portion (220) are opposite to each other, and the first connecting portion (230) and the second connecting portion (240) are respectively connected between opposite ends of the first arc-shaped portion (210) and the second arc-shaped portion (220).

4. The air duct structure according to claim 3, characterized in that: The opening directions of the air inlet (201) and the air outlet (202) are consistent with the flow direction of the gas in the external air duct (111) along the partition (200).

5. The air duct structure according to claim 4, characterized in that: The first connecting portion (230) is formed by extending from an end of the first arc-shaped portion (210) toward the second arc-shaped portion (220), an arc-shaped interval is formed between the end of the first connecting portion (230) and the end of the second arc-shaped portion (220) to form the air inlet (201), and the air inlet (201) is tangent to the outer arc surface of the second arc-shaped portion (220); The second connecting portion (240) is extended from the end of the second arc-shaped portion (220) toward the first arc-shaped portion (210), and an arc-shaped interval is formed between the end of the second connecting portion (240) and the end of the first arc-shaped portion (210) to form the exhaust port (202), and the exhaust port (202) is tangent to the outer arc surface of the first arc-shaped portion (210).

6. A hot air circulation drying device, characterized in that: include: A hot air generating mechanism (300), a first fan (400), and an air duct structure as described in any one of claims 1 to 5, wherein the first fan (400) and the hot air generating mechanism (300) are both installed in the external air duct (111), the hot air generating mechanism (300) is used to heat the airflow in the air cavity (110), and the first fan (400) is used to increase the airflow speed of the external air duct (111).

7. The hot air circulation drying equipment according to claim 6, characterized in that: The external air duct (111) is in a runway shape; the air inlet (201) and the air outlet (202) are both arranged at the turning positions on both sides of the partition (200); the first fan (400) is installed close to the air outlet (202); and the hot air generating mechanism (300) is installed close to the air inlet (201).

8. The hot air circulation drying equipment according to claim 7, characterized in that: The hot air generating mechanism (300) comprises an outer cylinder (310), an electric heating element (320) and a second fan (330); the outer cylinder (310) is provided with an air inlet end (311) and an air outlet end (312); the second fan (330) and the electric heating element (320) are installed in the outer cylinder (310); the airflow in the external air duct (111) enters the outer cylinder (310) through the air inlet end (311) and flows out from the air outlet end (312); and the rotation speed of the first fan (400) is greater than the rotation speed of the second fan (330).

9. The hot air circulation drying equipment according to claim 6, characterized in that: The shell (100) is provided with a pressure relief port (120) and an air inlet (130), and both the pressure relief port (120) and the air inlet (130) can connect the air cavity (110) to the outside of the shell (100). A pressure relief valve (500) is installed at the pressure relief port (120), and the pressure relief valve (500) controls the gas inside the air cavity (110) to be discharged to the outside of the shell (100) after reaching a preset pressure. An air intake valve (600) is provided at the air inlet (130), and the air intake valve (600) controls the gas outside the shell (100) to flow unidirectionally to the air cavity (110).

10. The hot air circulation drying equipment according to claim 6, characterized in that: The inner air duct (112) is installed with sound-absorbing cotton (700).

11. The hot air circulation drying equipment according to claim 6, characterized in that: A temperature sensor (800) is installed on the partition (200).

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