Heat exchanger structure applied to emergency grain dryer

Abstract

The invention discloses a heat exchanger structure applied to an emergency grain dryer. The heat exchanger structure comprises a combustion chamber, a heat collection cylinder, a smoke collection ring and an exhaust chimney. A heat exchange tube group which is arranged around the combustion chamber is connected between the heat collection cylinder and the smoke collection ring, and the heat exchange tube group is composed of heat exchange tubes; the heat exchange tube is spiral; the central angle between the head end and the tail end of each heat exchange pipe relative to the spiral center is not larger than 360 degrees. An inner layer heat exchange pipe and an outer layer heat exchange pipe are installed on the outer side of the combustion chamber, the rotating directions of all the heat exchange pipes on the same layer are consistent, and the rotating directions of the heat exchange pipes on different layers are opposite. According to the heat exchanger, the total number of the heat exchange pipes is guaranteed, meanwhile, the heat exchange area is greatly increased, the heat exchange efficiency can be improved, and heat energy waste is reduced. In addition, the inner heat exchange tube array and the outer heat exchange tube array with the opposite spiral directions can enable airflow to flow in alternating directions when the airflow passes through the heat exchange tubes in different layers, turbulent flow is formed to destroy heat boundary layers of the airflow and the wall faces of the heat exchange tubes, and the heat transfer coefficient is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of grain drying, and in particular to a heat exchanger structure applied to an emergency grain dryer. Background Art

[0002] Fresh grain has a high moisture content after harvest, necessitating rapid and thorough drying to achieve safe storage conditions and prevent mold and spoilage. Annual losses due to inadequate and timely drying exceed 5%. Particularly in June, some major grain-producing areas experience "rotten grain rain," further increasing grain losses. Emergency drying environments are complex, and wet grain has a high moisture content. Existing grain drying equipment suffers from low heat exchange efficiency, immobility, and slow precipitation rates, making it unsuitable for disaster prevention, emergency response, and rapid loss reduction.

[0003] In the prior art, patent CN 105928355 A discloses a heat dissipation mechanism for a dryer, which has a combustion chamber, a heat energy distribution chamber, an exhaust gas collection chamber, and a heat exchange tube. The heat energy distribution chamber and the exhaust gas collection chamber are placed at both ends of the combustion chamber, and the heat exchange tube is arranged around the combustion chamber and connects the heat energy distribution chamber and the exhaust gas collection chamber; a four-plate spiral guide heat exchange device is provided in the heat exchange tube. In this patent, although a spiral guide device is provided in the heat exchange tube, the heat exchange efficiency is still low. In other prior art, patent CN 219160896U provides a drying furnace with return air spiral heating, in which spiral blades are provided around the combustion chamber, forming a spiral heat exchange channel outside the combustion chamber. The fan injects air into the spiral channel, and the air absorbs heat from the outer wall of the combustion chamber. In this solution, the combustion flue gas and the air after heat exchange are used together for drying operations. Impurities in the flue gas cannot be removed, and it cannot be directly used for grain drying operations. In addition, patents such as CN 202675837 U use a spring-structured spiral tube for heat exchange, but the heat exchange area is still small and the heat of the combustion flue gas cannot be fully utilized. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a heat exchanger structure for an emergency grain dryer that can effectively improve heat exchange efficiency.

[0005] Technical solution: To achieve the above-mentioned purpose, the present invention provides a heat exchanger structure for an emergency grain dryer, comprising a combustion chamber, with a heat collecting tube and a smoke collecting ring respectively provided at both ends of the combustion chamber, the smoke collecting ring being connected to an exhaust chimney; a heat exchange tube group arranged around the combustion chamber is connected between the heat collecting tube and the smoke collecting ring, the heat exchange tube group being composed of heat exchange tubes;

[0006] The heat exchange tube is spiral-shaped, and the center of the spiral coincides with the center of the combustion chamber. The central angle between the first and last ends of each heat exchange tube relative to the spiral center does not exceed 360°, that is, when viewed in the axial direction of the combustion chamber, the projection of the entire heat exchange tube is a non-closed arc.

[0007] Two layers of heat exchange tubes are installed on the outside of the combustion chamber. The rotation directions of all the heat exchange tubes in the same layer are consistent, and the rotation directions of the heat exchange tubes in different layers are opposite. All the heat exchange tubes in the same layer are arranged in a circular array around the combustion chamber.

[0008] The combustion chamber is open at one end, near the smoke collection ring, and has a flange for connecting to the burner. During operation, the burner injects fuel and air into the combustion chamber in a specific ratio, causing the fuel to burn inside. The resulting flue gas enters the heat collection tube for transfer and is then dispersed into the heat exchange tubes. Finally, the flue gas in each heat exchange tube converges at the smoke collection ring and is discharged through the exhaust chimney. The heat exchange airflow passes through the outside of the heat exchange tubes and the outer wall of the combustion chamber to remove heat, and this heat-carrying airflow dries the grain.

[0009] Furthermore, the central angle between the first and last ends of each heat exchange tube relative to the spiral center is 180°, that is, the projected arc of the heat exchange tube in the axial direction of the combustion chamber is a semicircular arc.

[0010] Furthermore, both ends of all the heat exchange tubes are respectively fixed on the first transition ring and the second transition ring; the first transition ring is connected to a plurality of first connecting tubes for connecting to the heat collecting tube; the second transition ring is connected to a plurality of second connecting tubes for connecting to the smoke collecting ring; all the first connecting tubes and the second connecting tubes are straight tubes extending along the axial direction of the combustion chamber, and all the first connecting tubes and all the second connecting tubes are arranged in a circular array.

[0011] Furthermore, the ends of the first connecting pipe and the second connecting pipe are fixed with connecting flanges. During installation, the connecting flanges are fixed to the heat collecting tube and the smoke collecting ring respectively by screws to achieve a fixed connection relationship between the first connecting pipe and the second connecting pipe relative to the heat collecting tube and the smoke collecting ring respectively.

[0012] During actual production, the heat exchange tube, the first transition ring, the second transition ring, the first connecting tube and the second connecting tube form an integral component, which can be easily installed.

[0013] Furthermore, the first transition ring is composed of two first half rings respectively connected to the first connecting pipe and the heat exchange pipe, and the two first half rings are capable of rotating relative to each other;

[0014] The second transition ring is composed of two second half rings respectively connected to the second connecting pipe and the heat exchange pipe, and the two second half rings are capable of relative rotation;

[0015] The heat exchange tube group and the combination of the first half ring and the second half ring connected to the heat exchange tube group are driven by a driving mechanism to perform rotational motion. The driving mechanism includes a pulley connected to the first half ring.

[0016] During use, a heat exchange chamber is arranged around the heat exchanger structure. The blower injects airflow into the heat exchange chamber from the side of the heat exchange chamber close to the smoke collecting ring. The direction of the airflow is perpendicular to the axial direction of the combustion chamber. After the airflow enters the heat exchange chamber, it turns and moves along the axial direction of the combustion chamber.

[0017] Beneficial effects: The heat exchanger structure applied to the emergency grain dryer of the present invention has the following beneficial effects:

[0018] (1) In the present invention, by providing heat exchange tubes with a spiral angle of less than one turn and providing two inner and outer groups of heat exchange tube arrays with opposite spiral directions, the heat exchange area is greatly increased while ensuring the total number of heat exchange tubes, thereby improving heat exchange efficiency and reducing heat energy waste. In addition, the inner and outer groups of heat exchange tube arrays with opposite spiral directions can cause the airflow to flow in alternating directions when passing through different layers of heat exchange tubes, forming turbulence to destroy the thermal boundary layer between the airflow and the heat exchange tube wall, significantly improving the heat transfer coefficient.

[0019] (2) By setting up transition rings and connecting pipes, all heat exchange tubes can be integrated into a whole, which makes it convenient to install all heat exchange tubes between the heat collecting tube and the smoke collecting ring at one time, and can reduce the difficulty of installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a front view structural diagram of the heat exchanger structure used in the emergency grain dryer;

[0021] Figure 2 This is a three-dimensional structural diagram of the heat exchanger structure used in the emergency grain dryer;

[0022] Figure 3 This is a cross-sectional structural diagram of a heat exchanger used in an emergency grain dryer;

[0023] Figure 4 for Figure 2 A magnified structural diagram of part A;

[0024] Figure 5 Schematic diagram of air flow during heat exchange;

[0025] Figure 6 This is a structural diagram of the heat exchanger structure used in the emergency grain dryer in the preferred embodiment.

[0026] In the figure: 1-combustion chamber; 1a-connecting flange; 2-heat collecting tube; 3-smoke collecting ring; 4-heat exchange tube; 5-exhaust chimney; 6-first transition ring; 7-second transition ring; 8-first connecting pipe; 9-second connecting pipe; 10-pulley; a-connecting flange. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings.

[0028] like Figures 1 to 3 The heat exchanger structure shown in the figure is used in an emergency grain dryer. It includes a combustion chamber 1, with a heat collecting tube 2 and a smoke collecting ring 3 provided at both ends of the combustion chamber 1. The smoke collecting ring 3 is connected to an exhaust chimney 5. A heat exchange tube group arranged around the combustion chamber 1 is connected between the heat collecting tube 2 and the smoke collecting ring 3. The heat exchange tube group is composed of heat exchange tubes 4.

[0029] The heat exchange tube 4 is spiral-shaped, and the center of the spiral coincides with the center of the combustion chamber 1. The central angle between the first and last ends of each heat exchange tube 4 relative to the spiral center does not exceed 360°. That is, when viewed in the axial direction of the combustion chamber 1, the entire projection of the heat exchange tube 4 is a non-closed arc.

[0030] Two layers of heat exchange tubes 4 are installed on the outside of the combustion chamber 1. The rotation directions of all the heat exchange tubes 4 in the same layer are consistent, and the rotation directions of the heat exchange tubes 4 in different layers are opposite. All the heat exchange tubes 4 in the same layer are arranged in a circular array around the combustion chamber 1.

[0031] The combustion chamber 1 is open at one end near the smoke collecting ring 3 and has a connecting flange 1a for the burner. During operation, the burner injects fuel and air into the combustion chamber 1 in a predetermined ratio, causing the fuel to burn within the combustion chamber 1. The resulting flue gas enters the heat collecting tube 2 for transfer and is then dispersed into the heat exchange tubes 4. Finally, the flue gas in each heat exchange tube 4 converges into the smoke collecting ring 3 and is discharged through the exhaust chimney 5. The heat-exchanged airflow passes through the outside of the heat exchange tubes 4 and the outer wall of the combustion chamber 1, removing heat. This heat-carrying airflow then dries the grain.

[0032] Preferably, the central angle between the first and last ends of each heat exchange tube 4 relative to the spiral center is 180°, that is, the arc projected in the axial direction of the combustion chamber 1 is a semicircular arc.

[0033] In the present invention, by providing heat exchange tubes 4 with a spiral angle of less than one turn and providing two inner and outer arrays of heat exchange tubes with opposite spiral directions, the total number of heat exchange tubes 4 is maintained while significantly increasing the heat exchange area, thereby improving heat exchange efficiency and reducing heat energy waste. Furthermore, the inner and outer arrays of heat exchange tubes with opposite spiral directions create alternating directions of airflow as it passes through different layers of heat exchange tubes 4, creating turbulence that disrupts the thermal boundary layer between the airflow and the heat exchange tube walls, significantly improving the heat transfer coefficient.

[0034] Preferably, both ends of all the heat exchange tubes 4 are respectively fixed on the first transition ring 6 and the second transition ring 7; the first transition ring 6 is connected to a plurality of first connecting tubes 8 for connecting to the heat collecting tube 2; the second transition ring 7 is connected to a plurality of second connecting tubes 9 for connecting to the smoke collecting ring 3; all the first connecting tubes 8 and the second connecting tubes 9 are straight tubes extending along the axial direction of the combustion chamber 1, and all the first connecting tubes 8 and all the second connecting tubes 9 are arranged in a circular array.

[0035] Preferably, if Figure 4 As shown, the ends of the first connecting pipe 8 and the second connecting pipe 9 are fixed with connecting flanges a. During installation, the connecting flanges a are fixed to the heat collecting tube 2 and the smoke collecting ring 3 respectively by screws (the screws are not shown in the figure) to achieve a fixed connection relationship between the first connecting pipe 8 and the second connecting pipe 9 relative to the heat collecting tube 2 and the smoke collecting ring 3 respectively.

[0036] In actual production, the heat exchange tube 4, the first transition ring 6, the second transition ring 7, the first connecting tube 8 and the second connecting tube 9 form an integral component, which can be easily installed.

[0037] By providing a transition ring and a connecting pipe, all heat exchange tubes 4 can be integrated into a whole, making it convenient to install all heat exchange tubes 4 between the heat collecting tube 2 and the smoke collecting ring 3 at one time, thereby reducing the difficulty of installation.

[0038] When using, such as Figure 5 As shown, a heat exchange chamber is arranged around the heat exchanger structure, and a blower injects airflow into the heat exchange chamber from the side of the heat exchange chamber close to the smoke collecting ring 3. The direction of the airflow is perpendicular to the axial direction of the combustion chamber 1. After the airflow enters the heat exchange chamber, it turns and moves along the axial direction of the combustion chamber 1.

[0039] Preferably, in a preferred embodiment, as Figure 6 As shown, the first transition ring 6 is composed of two first half rings respectively connected to the first connecting pipe 8 and the heat exchange pipe 4, and the two first half rings can rotate relative to each other;

[0040] The second transition ring 7 is composed of two second half rings respectively connected to the second connecting pipe 9 and the heat exchange pipe 4, and the two second half rings are capable of relative rotation;

[0041] The combination of the heat exchange tube group and the first half ring and the second half ring connected to the heat exchange tube group is driven by a driving mechanism to rotate. The driving mechanism includes a pulley 10 connected to the first half ring. The pulley 10 is connected to the drive motor through a belt. The belt and the drive motor are not shown in the figure.

[0042] By rotating the assembly, on the one hand, the heat exchange tubes 4 can be blown directly by the air flow through the air inlet of the heat exchange chamber in turn to exchange heat, which can improve the heat exchange efficiency and avoid the heat exchange tubes 4 facing away from the air inlet from not being able to fully exchange heat; on the other hand, the heat exchange tubes 4 move alternately relative to the first connecting tube 8 and the second connecting tube 9, which can form a turbulent effect, reduce the flue gas flow rate, increase the flue gas residence time, further improve the heat exchange efficiency, and reduce heat waste.

[0043] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A heat exchanger structure for an emergency grain dryer, comprising a combustion chamber (1), wherein a heat collecting tube (2) and a smoke collecting ring (3) are respectively provided at both ends of the combustion chamber (1), and the smoke collecting ring (3) is connected to an exhaust chimney (5); a heat exchange tube group arranged around the combustion chamber (1) is connected between the heat collecting tube (2) and the smoke collecting ring (3), and the heat exchange tube group is composed of heat exchange tubes (4); and the characteristics are: The heat exchange tube (4) is spiral-shaped, and the spiral center coincides with the center of the combustion chamber (1); the central angle between the first and last ends of each heat exchange tube (4) relative to the spiral center does not exceed 360°; Two layers of heat exchange tubes (4) are installed on the outside of the combustion chamber (1). The rotation directions of all the heat exchange tubes (4) in the same layer are consistent, while the rotation directions of the heat exchange tubes (4) in different layers are opposite.

2. The heat exchanger structure used in the emergency grain dryer according to claim 1 is characterized in that: The central angle between the first and last ends of each heat exchange tube (4) relative to the spiral center is 180°.

3. The heat exchanger structure used in the emergency grain dryer according to claim 1 is characterized in that: Both ends of all the heat exchange tubes (4) are respectively fixed on a first transition ring (6) and a second transition ring (7); a plurality of first connecting tubes (8) for connecting to the heat collecting tube (2) are connected to the first transition ring (6); a plurality of second connecting tubes (9) for connecting to the smoke collecting ring (3) are connected to the second transition ring (7); all the first connecting tubes (8) and all the second connecting tubes (9) are arranged in a circular array.

4. The heat exchanger structure used in the emergency grain dryer according to claim 3 is characterized in that: The ends of the first connecting pipe (8) and the second connecting pipe (9) are both fixed with connecting flanges.

5. The heat exchanger structure used in the emergency grain dryer according to claim 3, characterized in that: The first transition ring (6) is composed of two first half rings respectively connected to the first connecting pipe (8) and the heat exchange pipe (4), and the two first half rings are capable of relative rotation; The second transition ring (7) is composed of two second half rings respectively connected to the second connecting pipe (9) and the heat exchange pipe (4), and the two second half rings are capable of relative rotation; The heat exchange tube group and the first half ring and the second half ring connected to the heat exchange tube group form a combined body which is driven by a driving mechanism to perform rotational motion.

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