Heat exchange mechanism of mobile grain dryer

Abstract

The application discloses a heat exchange mechanism of a mobile grain dryer, which comprises a combustion chamber, a flue pipe assembly arranged around the combustion chamber, a flue gas distribution chamber connected with the flue pipe assembly and the combustion chamber, and a smoke collecting ring connected with the flue pipe assembly and an exhaust pipe; the flue pipe assembly is composed of at least two pipe groups connected in series, the number of flue pipes contained in the pipe groups gradually increases in the flue gas flow direction, and the specifications of the flue pipes gradually become thinner from thick to thin. In the application, the flue pipe assembly with the number of flue pipes gradually increasing and the pipe diameter gradually decreasing is arranged in series to form a tapered heat exchange structure on the flue gas flow path, and the heat exchange efficiency is significantly improved by cooperating with the countercurrent heat exchange design. The front thick flue pipe reduces the flue gas resistance, the rear thin flue pipe increases the heat exchange area, the high-temperature flue gas heat gradient is released, and the drying airflow can sufficiently absorb the waste heat.

Description

Technical Field

[0001] This invention relates to the field of grain drying technology, and in particular to a heat exchange mechanism for a mobile grain dryer. Background Technology

[0002] After harvesting, grains have a high moisture content and need to be dried and stored promptly to prevent mold growth. In the prior art, patent CN 105928355 A discloses a heat dissipation structure specifically designed for mobile dryers. This structure has a heat outlet, with a flange at its outer end for connecting to the burner, and its inner end connected to the front end of the combustion chamber. The combustion chamber has a cylindrical design. A waste gas collection chamber is arranged around the heat outlet, and this chamber is enclosed by a waste gas collection chamber shell. An exhaust channel is located at the top of the waste gas collection chamber. Multiple heat exchange tubes are arranged around the outer wall of the combustion chamber, and each heat exchange tube contains a four-plate spiral flow-guiding heat exchange assembly. One end of the heat exchange tube is the exhaust end, connected to the waste gas collection chamber; the other end is the inlet end, connected to the heat energy equalization chamber. The heat energy equalization chamber is located at the rear end of the combustion chamber and contains heat energy equalization plates to achieve uniform heat distribution. In actual use, the heat exchange efficiency of this patented solution is relatively low, resulting in significant waste of the heat energy generated by combustion. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a heat exchange mechanism for a mobile grain dryer that can effectively improve heat exchange efficiency and improve the utilization rate of flue gas heat energy.

[0004] Technical solution: To achieve the above objectives, the heat exchange mechanism of the mobile grain dryer of the present invention includes a combustion chamber, a flue pipe assembly arranged around the combustion chamber, a flue gas distribution chamber connecting the flue pipe assembly and the combustion chamber, and a smoke collection ring connecting the flue pipe assembly and the exhaust pipe.

[0005] The flue assembly consists of at least two pipe sections connected in series. In the direction of flue gas flow, the number of flue pipes in the pipe assembly gradually increases, and the specifications of the flue pipes gradually decrease from thick to thin. That is, the flue assembly containing more and thinner flue pipes is closer to the smoke collection ring, while the flue assembly containing fewer and thicker flue pipes is closer to the flue gas distribution chamber.

[0006] In operation, the external burner injects fuel and control fluid into the combustion chamber for combustion. The resulting flue gas first enters the flue gas distribution chamber, then sequentially enters each flue pipe assembly, and finally converges at the flue gas collection ring and is discharged through the exhaust pipe. The airflow participating in heat exchange for grain drying moves against the direction of flue gas movement in the flue pipes. That is, the airflow participating in heat exchange first passes through the flue pipe assembly containing a large number of thin flue pipes, and then passes through the flue pipe assembly containing a small number of thick flue pipes.

[0007] Furthermore, in the two adjacent sets of the smoke tube assemblies, each is composed of a coarse smoke tube and a fine smoke tube, and each coarse smoke tube has a corresponding number of fine smoke tubes. Under normal use, all the fine smoke tubes corresponding to the same coarse smoke tube are arranged in a circular array around the central axis of the coarse smoke tube.

[0008] Furthermore, each of the flues has a spiral guide vane.

[0009] Furthermore, adjacent sets of the flue assembly are connected by a connecting ring, which is a hollow circular ring structure with connection ports on both sides for connecting the flue on both sides.

[0010] Furthermore, the number of the flue pipe assemblies is two sets; the connecting ring is composed of two half rings, namely the first half ring and the second half ring, which are respectively connected to the flue pipe assembly composed of thin flue pipes and the flue pipe assembly composed of thick flue pipes; and one end of the flue pipe assembly composed of thin flue pipes is fixed with a transition ring that can rotate relative to the smoke collecting ring; one end of the flue pipe assembly composed of thick flue pipes is fixedly installed relative to the flue gas distribution chamber.

[0011] In this design, the two sets of flue pipe assemblies are a sparsely distributed section and a densely distributed section arranged sequentially in the direction of flue gas flow. The sparsely distributed section contains multiple first flue pipes arranged in a circumferential array, and the densely distributed section contains multiple groups of thin flue pipes arranged in a circumferential array. Under normal use, each group of thin flue pipes contains four second flue pipes arranged in a circumferential array, and the center of the circumferential array is coaxial with the center of the corresponding first flue pipe. The first flue pipes are thicker than the second flue pipes.

[0012] In the above structure, by connecting a semi-ring and a transition ring to both ends of the flue assembly composed of thin flues, the combined body formed by the three can rotate relative to the combustion chamber, enabling the following two applications:

[0013] The first method involves adjusting the angle of the exhaust pipe if the temperature of the flue gas is too high. This allows the first exhaust pipe and its corresponding thin exhaust pipe group to be offset by a certain angle, creating a turbulence effect, slowing down the flow of the flue gas, increasing the heat exchange time of the exhaust pipe, and enabling the flue gas to fully exchange heat with the outside air through the pipe wall. Preferably, a first turbulence plate and a second turbulence plate are installed in the first and second half-rings, respectively, extending radially along their respective half-rings. Under normal operating conditions, the first and second turbulence plates are aligned, allowing the flue gas to smoothly enter the corresponding thin exhaust pipe group from the first exhaust pipe. When the first and second half-rings are offset by a certain angle, the first and second turbulence plates are staggered, reconstructing the flue structure within the connecting ring. The flue gas exiting the first exhaust pipe needs to pass through an S-shaped path into the second exhaust pipe, effectively slowing down the flow of the flue gas.

[0014] The second type involves a combination assembly that can rotate continuously under the action of a drive mechanism. In actual use, a heat exchange chamber is provided on the outer side of the heat exchange mechanism, and an air inlet is provided on the side of the heat exchange chamber near the smoke collection ring. A fan blows airflow into the heat exchange chamber from the air inlet. The airflow direction is perpendicular to the axial direction of the combustion chamber. After entering the heat exchange chamber, the airflow changes to move axially, that is, along the axial direction of the combustion chamber. By making the combination assembly rotate continuously, each group of second smoke pipes can pass through the air inlet in turn, which can effectively improve the heat exchange efficiency. In addition, the continuous rotation of the combination assembly can also play a turbulence role, slowing down the flow of flue gas.

[0015] Beneficial effects: The heat exchange mechanism of the mobile grain dryer of the present invention has the following beneficial effects:

[0016] (1) In this invention, by setting up flue pipe assemblies with increasing numbers and decreasing diameters in series, a gradually narrowing heat exchange structure is formed on the flue gas flow path. Combined with the counter-flow heat exchange design, the heat exchange efficiency is significantly improved. The thicker flue pipe at the front reduces the flue gas resistance, while the thinner flue pipe at the rear increases the heat exchange area, allowing the heat of the high-temperature flue gas to be released in a gradient, ensuring that the drying airflow fully absorbs the residual heat.

[0017] (2) A nested layout of coarse flue pipes and arrayed fine flue pipes is adopted to achieve flue gas diversion and uniform heat field distribution. Each coarse flue pipe corresponds to an array of multiple fine flue pipes, forming a tree-like heat transfer structure that effectively balances the flow rate of each flue pipe. The transition design from sparse to dense sections ensures the initial uniformity of flue gas diffusion and enhances the end heat transfer intensity through the multiplication of fine pipes, thereby improving the uniformity of heat exchange.

[0018] (3) The introduction of spiral guide vanes can significantly improve the flow field characteristics inside the flue. The swirling effect formed by the spiral guide vanes prolongs the residence time of the flue gas, enhances the turbulence effect, breaks the boundary layer of the pipe wall, and improves the convective heat transfer coefficient between the pipe wall and the drying airflow. Attached Figure Description

[0019] Figure 1 This is a structural diagram of the heat exchange mechanism of a mobile grain dryer;

[0020] Figure 2 This is a cross-sectional view of the heat exchange mechanism of a mobile grain dryer.

[0021] Figure 3 for Figure 1 AA sectional view of the structure;

[0022] Figure 4 for Figure 1 BB cross-sectional structural diagram;

[0023] Figure 5 This is a structural diagram of the heat exchange mechanism in the preferred embodiment;

[0024] Figure 6 This is a structural diagram of the combined heat exchange mechanism and heat exchange cavity;

[0025] Figure 7 for Figure 5 CC cross-sectional view of the structure;

[0026] Figure 8 for Figure 5 DD cross-sectional structure diagram.

[0027] In the diagram: 1-combustion chamber; 2-smoke pipe assembly; 21-smoke pipe; 2A-sparse distribution section; 21a-first smoke pipe; 2B-dense distribution section; 21b-second smoke pipe; 3-smoke distribution chamber; 4-exhaust pipe; 5-smoke collection ring; 6-connecting ring; 61-first half-ring; 62-second half-ring; 63-first baffle; 64-second baffle; 7-transition ring. Detailed Implementation

[0028] The invention will now be further described with reference to the accompanying drawings.

[0029] like Figure 1 and Figure 2 The heat exchange mechanism of the mobile grain dryer shown includes a combustion chamber 1, a flue pipe assembly 2 arranged around the combustion chamber 1, a flue gas distribution chamber 3 connecting the flue pipe assembly 2 and the combustion chamber 1, and a smoke collection ring 5 connecting the flue pipe assembly 2 and the exhaust pipe 4.

[0030] The flue assembly 2 consists of at least two pipe sections connected in series. In the direction of flue gas flow, the number of flue pipes 21 included in the pipe assembly gradually increases, and the specifications of the flue pipes 22 gradually decrease from thick to thin. That is, the flue assembly 2 containing more and thinner flue pipes 21 is closer to the smoke collection ring 5, while the flue assembly 2 containing fewer and thicker flue pipes 21 is closer to the flue gas distribution chamber 3.

[0031] In operation, the external burner injects fuel and control fluid into the combustion chamber 1 for combustion. The resulting flue gas first enters the flue gas distribution chamber 3, then sequentially enters each flue pipe assembly 2, and finally converges into the smoke collection ring 5 and is discharged through the exhaust pipe 4. The airflow participating in heat exchange for grain drying moves against the direction of flue gas movement in the flue pipes 21. That is, the airflow participating in heat exchange first passes through the flue pipe assembly 2, which contains a large number of thin flue pipes 21, and then passes through the flue pipe assembly 2, which contains a small number of thick flue pipes 21.

[0032] In this invention, by assemblies 2 with increasing numbers and decreasing diameters of flue pipes connected in series, a gradually narrowing heat exchange structure is formed along the flue gas flow path. Combined with a counter-flow heat exchange design, this significantly improves heat exchange efficiency. The thicker flue pipes at the front reduce flue gas resistance, while the thinner flue pipes at the rear increase the heat exchange area, allowing the high-temperature flue gas to release heat gradients and ensuring that the drying airflow fully absorbs residual heat.

[0033] Preferably, in two adjacent sets of the smoke tube assemblies 2, each is composed of a coarse smoke tube and a fine smoke tube. Each coarse smoke tube has a corresponding plurality of fine smoke tubes. Under normal use, all the fine smoke tubes corresponding to the same coarse smoke tube are arranged in a circular array around the central axis of the coarse smoke tube. Here, "coarse smoke tube" and "fine smoke tube" are relative terms. For example, if there are three sets of smoke tube assemblies 2, the smoke tube 21 in the middle smoke tube assembly 2 is a fine smoke tube relative to the smoke tube 21 in the preceding smoke tube assembly 2, while the smoke tube 21 in the middle smoke tube assembly 2 is a coarse smoke tube relative to the smoke tube 21 in the following smoke tube assembly 2.

[0034] The nested layout of coarse flue tubes and arrayed fine flue tubes achieves flue gas diversion and uniform heat field distribution. Each coarse flue tube corresponds to an array of multiple fine flue tubes, forming a tree-like heat transfer structure that effectively balances the flow rate of each flue tube. The transition design from sparse to dense sections ensures the initial uniformity of flue gas diffusion and enhances the end-point heat transfer intensity through the multiplication of fine tubes, thereby improving the uniformity of heat exchange.

[0035] Preferably, each of the flue pipes 21 has a spiral guide vane 22.

[0036] The introduction of the spiral guide vane 22 can significantly improve the flow field characteristics inside the flue. The swirling effect formed by the spiral guide vane 22 prolongs the residence time of the flue gas, enhances the turbulence effect to break the boundary layer of the pipe wall, and improves the convective heat transfer coefficient between the pipe wall and the drying airflow.

[0037] Preferably, adjacent sets of the flue pipe assemblies 2 are connected by a connecting ring 6. The connecting ring 6 is a hollow circular ring structure, with connection ports on both sides connecting the flue pipes 21 on both sides. The annular hollow structure of the connecting ring 6 solves the sealing and assembly problem of multi-segment flue pipe assemblies, allowing the flue gas to smoothly transition between different flue pipe assemblies 2.

[0038] In this embodiment, the two sets of flue pipe assemblies 2 are respectively sparsely distributed sections 2A and densely distributed sections 2B arranged sequentially in the flue gas flow direction, such as Figure 3 As shown, the sparsely distributed segment 2A contains multiple first smoke tubes 21a arranged in a circular array, such as... Figure 4As shown, the densely distributed segment 2B contains multiple groups of thin smoke tubes arranged in a circular array. Under normal use, each group of thin smoke tubes contains four second smoke tubes 21b arranged in a circular array. The center of the circular array is coaxial with the center of the corresponding first smoke tube 21a. The first smoke tube 21a is thicker than the second smoke tubes 21b.

[0039] In actual use, such as Figure 6 As shown, a heat exchange chamber is provided on the outside of the heat exchange mechanism. An air inlet is provided on the side of the heat exchange chamber near the smoke collection ring 5. The fan blows air into the heat exchange chamber from the air inlet. The direction of the air flow is perpendicular to the axial direction of the combustion chamber 1. After entering the heat exchange chamber, the air flow changes to move along the axial direction, that is, it moves along the axial direction of the combustion chamber 1.

[0040] Preferably, the number of the flue assembly 2 is two sets; such as Figure 5 As shown, the connecting ring 6 is composed of two half-rings, namely the first half-ring 61 and the second half-ring 62, which are respectively connected to the smoke pipe assembly 2 composed of thin smoke pipes and the smoke pipe assembly 2 composed of thick smoke pipes; and one end of the smoke pipe assembly 2 composed of thin smoke pipes is fixed with a transition ring 7 that can rotate relative to the smoke collecting ring 5; one end of the smoke pipe assembly 2 composed of thick smoke pipes is fixedly installed relative to the flue gas distribution chamber 3.

[0041] In the above structure, by connecting the two ends of the flue assembly 2, which consists of thin flues, to the semi-rings 61 and the transition rings 7, the assembly formed by the three can rotate relative to the combustion chamber 1, thus achieving the following two uses:

[0042] Firstly, if the temperature of the flue gas discharged from the exhaust pipe 4 is too high, the angle of the adjustment assembly can be rotated to offset the first exhaust pipe 21a and its corresponding thin exhaust pipe group by a certain angle, thereby achieving a turbulence effect, slowing down the flow speed of the flue gas, increasing the heat exchange time of the exhaust pipe, and allowing the flue gas to fully exchange heat with the outside air through the pipe wall of the exhaust pipe 21. Preferably, as follows... Figure 7 and Figure 8 As shown, a first baffle plate 63 and a second baffle plate 64 are respectively installed in the first half-ring 61 and the second half-ring 62. The first baffle plate 63 and the second baffle plate 64 extend radially along the corresponding half-ring. Under normal use, the first baffle plate 63 and the second baffle plate 64 are aligned one to one, and the flue gas can smoothly enter the thin flue group corresponding to the first flue pipe 21a. When the first half-ring 61 and the second half-ring 62 are offset by a certain angle, the first baffle plate 63 and the second baffle plate 64 are offset from each other, which reconstructs the flue structure in the connecting ring 6. The flue gas coming out of the first flue pipe 21a needs to enter the second flue pipe 21b through an S-shaped path, which can effectively slow down the flow speed of the flue gas.

[0043] Secondly, the aforementioned assembly can rotate continuously under the action of a driving mechanism (such as a motor and belt mechanism). By making the assembly rotate continuously, each group of second flue pipes 21b can pass through the air inlet in turn, which can effectively improve the heat exchange efficiency. In addition, the continuous rotation of the assembly can also play a turbulence role, slowing down the flow efficiency of flue gas.

[0044] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A heat exchange mechanism for a mobile grain dryer, comprising a combustion chamber (1), a flue assembly (2) arranged around the combustion chamber (1), a flue gas distribution chamber (3) connecting the flue assembly (2) and the combustion chamber (1), and a smoke collection ring (5) connecting the flue assembly (2) and the exhaust pipe (4); characterized in that: The flue assembly (2) consists of at least two pipe groups connected in series. In the direction of flue gas flow, the number of flue pipes (21) included in the pipe group gradually increases, and the specifications of the flue pipes (21) gradually become thinner. The adjacent two sets of the smoke pipe assemblies (2) are connected by a connecting ring (6). The connecting ring (6) is a hollow circular ring structure, and its two sides have connection ports for connecting the smoke pipes (21) on both sides. The number of the flue pipe assembly (2) is two sets; the connecting ring (6) is composed of two half rings, namely the first half ring (61) and the second half ring (62), which are respectively connected to the flue pipe assembly (2) composed of thin flue pipes and the flue pipe assembly (2) composed of thick flue pipes; and one end of the flue pipe assembly (2) composed of thin flue pipes is fixed with a transition ring (7) that can rotate relative to the smoke collection ring (5), and one end of the flue pipe assembly (2) composed of thick flue pipes is fixedly installed relative to the flue gas distribution chamber (3); The smoke pipe assembly (2) consisting of a thin smoke pipe, the half ring (61) connected to both ends, and the transition ring (7) together form a combination. When the temperature of the flue gas discharged from the exhaust pipe (4) is higher than the set threshold, the angle position of the combination can be adjusted by rotation, or the combination can be continuously rotated under the action of the drive mechanism.

2. The heat exchange mechanism of the mobile grain dryer according to claim 1, characterized in that, In the two adjacent sets of the smoke tube assembly (2), each is composed of a coarse smoke tube and a fine smoke tube respectively. Each coarse smoke tube has a corresponding number of fine smoke tubes, and all the fine smoke tubes corresponding to the same coarse smoke tube are arranged in a circular array around the central axis of the coarse smoke tube.

3. The heat exchange mechanism of the mobile grain dryer according to claim 1, characterized in that, Each of the said flue pipes (21) has a spiral guide vane (22).

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