Heating module and reflow soldering furnace

Abstract

The invention discloses a heating module and a reflow soldering furnace, the heating module comprises an upper heating module and a lower heating module, the upper heating module is provided with an outer shell I, an outer shell II and an inner shell III; the first inner shell is arranged in the first outer shell, the first inner shell and the first outer shell are arranged in a spaced mode, so that a first air channel is defined between the first outer shell and the first inner shell, and the lower ends of the first outer shell and the first inner shell are open; and the fan is arranged at the upper ends of the first outer shell and the first inner shell and is detachably, hermetically and fixedly connected with the first outer shell and the first inner shell, after the fan is started, external gas is extracted to enter the first gas channel from bottom to top, and then the fan injects the gas in the first gas channel into the first inner shell from top to bottom. The reflow soldering furnace has the beneficial effects that the heating module in the reflow soldering furnace is convenient to maintain, the heating wire, the impeller motor assembly, the thermocouple assembly and other parts of the heating module are easy, convenient and rapid to disassemble and assemble, and the problem that the heating module in an existing reflow soldering furnace is inconvenient to maintain is effectively solved.

Description

Technical Field

[0001] The invention relates to the field of reflow soldering furnaces, and in particular to a heating module and a reflow soldering furnace. Background Art

[0002] A reflow oven is a device that provides a heating environment to melt the solder paste so that surface mounted components and circuit boards can be reliably combined together through the solder paste alloy.

[0003] The nitrogen protection in the reflow oven prevents easily oxidized materials such as solder and silver in the reflow zone from being oxidized at high temperatures, thus avoiding welding defects.

[0004] As we all know, in SMT (Surface Mounting Technology) production, various electrical components are combined with PCB boards through the melting and solidification of solder paste. The control of the soldering process is very important during the entire heating and cooling stages of soldering, especially the heating stage.

[0005] As surface mount technology and processes become more and more mature, customers are constantly putting forward new requirements for reflow ovens. Customers' products are getting bigger and bigger, and they are more demanding on the reflow ovens to complete the welding of components with high quality. They are also putting forward new requirements on equipment production capacity, energy saving and consumption reduction, equipment maintenance, etc., in pursuit of maximizing economic benefits.

[0006] As the width of the product increases, the furnace is getting wider. Conventional heating modules are the same on the upper and lower parts and are installed in pairs. Both the upper and lower furnaces have heating wires, impeller motor assemblies, thermocouple assemblies, etc. Since there are often chains and (or) mesh belts under the lower furnace, it is not convenient for personnel to enter, and it is very inconvenient to replace the impeller motor and thermocouple assemblies. At the same time, the heating wire body often needs to open the furnace cover and remove many parts before the heating wire body can be taken out, which is very time-consuming and labor-intensive. Summary of the invention

[0007] The main purpose of the present invention is to provide a heating module and a reflow soldering furnace, aiming to solve the problem of inconvenient maintenance of the heating module in the existing reflow soldering furnace.

[0008] In order to solve the above problems, the present invention proposes a heating module, comprising an upper heating module and a lower heating module, wherein the upper heating module has:

[0009] Outer shell one;

[0010] An inner shell body 1 is arranged in the outer shell body 1 and is spaced apart from the outer shell body 1, so as to define an air outlet 1 between the outer shell body 1 and the inner shell body 1, and the lower ends of the outer shell body 1 and the inner shell body 1 are open;

[0011] The fan is arranged at the upper ends of the outer shell 1 and the inner shell 1, and is detachably sealed and fixedly connected to the outer shell 1 and the inner shell 1. After the fan is started, the fan draws external air from bottom to top into the air passage 1, and then the fan injects the air in the air passage 1 into the interior of the inner shell 1 from top to bottom;

[0012] An air filling tube, one end of which is located outside the outer shell, and the other end of which passes through the outer shell and is connected to the airway;

[0013] A temperature detection device, which passes through the outer shell 1 and the inner shell 1 and is used to detect the air temperature inside the inner shell 1;

[0014] The lower heating module has:

[0015] The second outer shell has an open upper end and is detachably sealed and fixedly connected to the lower end of the first outer shell;

[0016] The second partition plate is disposed at two opposite ends of the second outer shell and is spaced apart from two opposite inner side walls of the second outer shell, so that a second airway is defined between the second partition plate and the inner side wall of the second outer shell, the upper end of the second airway is connected to the lower end of the first airway, and the upper end of the second partition plate is detachably sealed and fixedly connected to the lower end of the first inner shell;

[0017] The porous plate 3 is arranged between the two partition plates 2 at the upper end of the outer shell 2, and the airflow in the inner shell 1 flows downward into the lower furnace body and passes through the porous plate 3 and then continues to flow downward;

[0018] The partition plate 1 is arranged below the porous plate 3 in the outer shell 2 and is spaced apart from the inner bottom surface of the outer shell 2. The partition plate 1 is provided with a vent. The area between the partition plate 1 and the inner bottom surface of the outer shell 2 is connected to the lower end of the airway 2.

[0019] The heating device is arranged between the partition plate 1 and the inner bottom surface of the outer shell 2. The airflow passing through the porous plate 3 continues to flow downward through the vent and enters between the partition plate 1 and the inner bottom surface of the outer shell 2.

[0020] In one embodiment, a porous plate 1 is disposed in the inner shell 1, and the porous plate 1 is located directly below the fan. The airflow blown out by the fan hits the upper surface of the porous plate 1, and then the airflow passes through the porous plate 1 and flows downward.

[0021] In one embodiment, a porous plate 2 is provided at the open lower end of the inner shell 1. The airflow passing through the porous plate 1 continues to flow downward and passes through the porous plate 2 before entering the lower furnace body. The airflow passing through the porous plate 2 and entering the lower furnace body continues to flow downward and passes through the porous plate 3.

[0022] In one embodiment, the heating device is detachably plug-in and sealed to the second outer shell.

[0023] In one embodiment, one end of the heating device is located on the outer side of the second outer shell, and a second heat insulation board is provided at one end of the heating device.

[0024] In one embodiment, the porous plate three is located inside the outer shell two.

[0025] In addition, the present invention also proposes a reflow soldering furnace, comprising a lower furnace body and an upper furnace body, the upper furnace body comprising an upper furnace chamber and an upper heating module arranged in the upper furnace chamber, the lower furnace body comprising a lower furnace chamber and a lower heating module arranged in the lower furnace chamber, the upper furnace chamber and the lower furnace chamber are detachably sealed and fixedly connected, and the upper heating module and the lower heating module are the upper heating module and the lower heating module in the aforementioned heating modules.

[0026] In one embodiment, the outer shell is fixedly connected to the inner wall of the upper furnace;

[0027] The lower end of the upper furnace is open;

[0028] The fan is arranged at the upper end of the outer shell 1, the inner shell 1 and the upper furnace, and is detachably and sealedly fixedly connected with the outer shell 1, the inner shell 1 and the upper furnace;

[0029] One end of the inflation pipe is located outside the upper furnace, and the other end passes through the upper furnace and the outer shell and is connected to the airway;

[0030] The temperature detection device passes through the upper furnace, outer shell 1 and inner shell 1, and is sealed and fixedly connected to the upper furnace;

[0031] A heat insulation board 1 is filled between the outer shell 1 and the inner wall of the upper furnace.

[0032] In one embodiment, the second outer shell is fixedly connected to the inner wall of the lower furnace;

[0033] The upper end of the lower furnace is open;

[0034] The porous plate three is located inside the lower furnace.

[0035] In one embodiment, sealing strips are sandwiched between the lower end surface of the upper furnace and the upper end surface of the lower furnace, between the upper end surface of the outer shell 2 and the lower end surface of the outer shell 1, and between the lower end surface of the inner shell 1 and the upper end surface of the partition 2.

[0036] Beneficial effects: The heating module in the reflow soldering furnace of the present application is easy to repair and maintain, and the components of the heating module such as the heating wire, impeller motor assembly, and thermocouple assembly are simple, convenient, and quick to disassemble and assemble, which effectively solves the problem of inconvenient maintenance of the heating module in the existing reflow soldering furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 It is a front view of a reflow oven of the present invention;

[0039] Figure 2 yes Figure 1 AA section view in;

[0040] Figure 3 yes Figure 2 A schematic diagram of the structure of the upper furnace body;

[0041] Figure 4 yes Figure 2 A schematic diagram of the structure of the lower furnace body;

[0042] Figure 5 This is a schematic diagram of the structure of the heating module of the present invention. Figure 1 ;

[0043] Figure 6 This is a schematic diagram of the structure of the heating module of the present invention. Figure 2 ;

[0044] Figure 7 This is a schematic diagram of the structure of the heating module of the present invention. Figure 1 ;

[0045] Figure 8 This is a schematic diagram of the structure of the heating module of the present invention. Figure 2 ;

[0046] Fig. 9 The structure of the heating device of the present invention is shown in FIG. Figure 1 ;

[0047] Fig.10 The structure of the heating device of the present invention is shown in FIG. Figure 2 .

[0048] The following are the descriptions of the reference numerals:

[0049] 1. Upper furnace; 2. Heat insulation board 1; 3. Temperature detection device; 4. Gas filling pipe; 5. Sealing strip; 6. Outer shell 1; 7. Inner shell 1; 8. Air duct 1; 9. Fan; 10. Perforated plate 1; 11. Perforated plate 2;

[0050] 12. Lower furnace; 13. Perforated plate three; 14. Partition plate one; 15. Ventilation port; 16. Heating device; 17. Sealing pad; 18. Outer shell two; 19. Partition plate two; 20. Airway two; 21. Heat insulation board two; 22. Mounting groove;

[0051] 100, upper furnace body; 200, lower furnace body. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0054] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" 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, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0056] The present invention proposes a heating module and a reflow soldering furnace. The heating module is installed in the reflow soldering furnace. The heating module in the reflow soldering furnace is easy to repair and maintain. The components of the heating module such as the heating wire, the impeller motor assembly, and the thermocouple assembly are simple, convenient, and quick to disassemble and assemble, which effectively solves the problem of inconvenient maintenance of the heating module in the existing reflow soldering furnace.

[0057] Specifically, in one embodiment of the invention, Figure 1 and Figure 2 As shown, the reflow oven includes a lower furnace body 200 and an upper furnace body 100. Figure 2 As shown, the upper furnace body 100 includes an upper furnace chamber 1 and an upper heating module arranged in the upper furnace chamber 1, and the lower furnace body 200 includes a lower furnace chamber 12 and a lower heating module arranged in the lower furnace chamber 12. The upper furnace chamber 1 and the lower furnace chamber 12 are detachably sealed and fixedly connected. The heating module of the present invention includes the upper heating module and the lower heating module.

[0058] Specifically, a sealing strip 5 is sandwiched between the lower end surface of the upper furnace 1 and the upper end surface of the lower furnace 12, and the upper furnace 1 and the lower furnace 12 are detachably sealed and fixedly connected through the sealing strip 5. A sealing strip 5 is also sandwiched between the upper heating module and the lower heating module, and the upper heating module and the lower heating module are detachably sealed and fixedly connected through the sealing strip 5.

[0059] Specifically, Figure 2 , Figure 3 , Figure 5 and Figure 6As shown, the upper heating module includes: an outer shell 6, an inner shell 7, a fan 9, an inflation pipe 4, and a temperature detection device 3. The outer shell 6 is fixedly connected to the inner wall of the upper furnace 1; the inner shell 7 is arranged in the outer shell 6 and is spaced from the outer shell 6, so that an air outlet 8 is defined between the outer shell 6 and the inner shell 7. The lower ends of the outer shell 6, the inner shell 7, and the upper furnace 1 are open; the fan 9 is arranged at the upper ends of the outer shell 6, the inner shell 7, and the upper furnace 1, and is detachably sealed and fixedly connected to the outer shell 6, the inner shell 7, and the upper furnace 1. This design facilitates the disassembly and assembly of the fan 9. The fan 9 includes an impeller motor assembly. After the fan 9 is started, it draws external air from bottom to top into the air chamber. 8, and then the fan 9 injects the gas in the air duct 8 into the interior of the inner shell 7 from top to bottom; one end of the inflation pipe 4 is located outside the upper furnace 1, and the other end passes through the upper furnace 1 and the outer shell 6 to be connected with the air duct 8. With this design, nitrogen can be injected into the air duct 8 through the external nitrogen of the inflation pipe 4. The temperature detection device 3 passes through the upper furnace 1, the outer shell 6 and the inner shell 7, and is sealed and fixedly connected to the upper furnace 1, for detecting the air temperature inside the inner shell 7, thereby facilitating the controller to adjust the heating power of the heating device 16. Commonly, the temperature detection device 3 is a thermocouple assembly, and the temperature detection device 3 passes through the upper furnace 1, the outer shell 6 and the inner shell 7 to facilitate the disassembly and assembly of the temperature detection device 3.

[0060] Further, such as Figure 2 As shown, an insulation board 2 is filled between the outer shell 6 and the inner wall of the upper furnace 1, and the insulation board 2 is used for heat insulation and supporting connection between the outer shell 6 and the upper furnace 1. Preferably, the insulation board 2 is made of gypsum.

[0061] In this embodiment, if Figure 2 and Figure 3 , Figure 5 and Figure 6 As shown, a porous plate 10 is arranged in the inner shell 7, and the porous plate 10 is located directly below the fan 9. The airflow blown by the fan 9 hits the upper surface of the porous plate 10, and then the airflow passes through the porous plate 10 and flows downward. The porous plate 10 can block the airflow, thereby forming an airflow static pressure bin. The static pressure bin can enable the porous plate 10 to achieve the effect of uniformly supplying air to the downward furnace body 200, reduce the airflow noise, and facilitate the airflow to flow farther and more evenly, so that the porous plate 10 can blow out a uniform airflow downward, and the wind speed and temperature are consistent at all places in the airflow.

[0062] Furthermore, in this embodiment, if Figure 3As shown, a porous plate 11 is provided at the lower open end of the inner shell 7. The airflow passing through the porous plate 10 continues to flow downward and passes through the porous plate 11 before entering the lower furnace body 200. The porous plate 11 is used to fix the inner shell 7 and the outer shell 6 together.

[0063] In this embodiment, if Figure 2 , Figure 4 , Figure 7-Figure 10 As shown, the lower heating module includes: an outer shell 2 18, a partition 2 19, a porous plate 3 13, a partition 14, and a heating device 16. The outer shell 2 18 is fixedly connected to the inner wall of the lower furnace 12. The upper ends of the outer shell 2 18 and the lower furnace 12 are open. A sealing strip 5 is sandwiched between the lower end surface of the upper furnace 1 and the upper end surface of the lower furnace 12, between the upper end surface of the outer shell 2 18 and the lower end surface of the outer shell 1 6, and between the lower end surface of the inner shell 1 7 and the upper end surface of the partition 2 19, so that the upper furnace 1 and the lower furnace 12 are detachably sealed and fixedly connected through the sealing strip 5, and the upper heating module and the lower heating module are detachably sealed and fixedly connected through the sealing strip 5; as shown Figure 7 and Figure 8 As shown, the second partition plate 19 is disposed at opposite ends of the second outer shell 18 and is spaced apart from the two opposite inner side walls of the second outer shell 18, thereby defining an air outlet 20 between the second partition plate 19 and the inner side wall of the second outer shell 18. Figure 2 As shown, the upper end of the airway 20 is connected to the lower end of the airway 1 8; Figure 7 and Figure 8 As shown, the porous plate 3 13 is arranged between the two partitions 2 19 at the upper end of the outer shell 2 18, and the airflow that passes through the porous plate 2 11 and enters the lower furnace body 200 continues to flow downward and passes through the porous plate 3 13; the partition 14 is arranged below the porous plate 3 13 in the outer shell 2 18, and is spaced from the inner bottom surface of the outer shell 2 18, and the partition 14 is provided with a vent 15, and the area between the partition 14 and the inner bottom surface of the outer shell 2 18 is connected to the lower end of the air duct 20; the heating device 16 is arranged between the partition 14 and the outer shell 2 After passing through the inner bottom surface of the porous plate three 18, the airflow continues to flow downward through the vent 15 into the space between the partition one 14 and the inner bottom surface of the outer shell two 18, and is heated by the heating device 16. Then the hot air rises along the air outlet 20 into the air duct one 8, and is finally injected into the inner shell one 7 by the fan 9. The hot air in the inner shell one 7 flows downward into the lower furnace 12 to heat the product placed on the upper surface of the porous plate three 13. The airflow circulates in the heating module of the reflow soldering furnace through the cooperation of the fan 9 and the heating device 16. The flow direction is as follows: Figure 2 Indicated by the arrow.

[0064] Specifically, the heating device 16 is a fin-type electric heating device 16, which includes a heating wire, such as Figure 7-Figure 10 As shown, the heating device 16 is detachably plugged and sealed to one end of the outer shell 18. This design facilitates the disassembly and assembly of the heating device 16 without replacing any components under the lower furnace 12, which greatly reduces the difficulty of repair and maintenance of the heating module. Figure 4 As shown, a sealing gasket 17 is provided between the heating device 16 and the outer side surface of one end of the outer shell 18, and the sealing gasket 17 is used to achieve the sealing between the heating device 16 and the outer side surface of one end of the outer shell 18. Fig.10 As shown, a mounting groove 22 is provided in an area on the heating device 16 connected to the outer side surface of one end of the outer shell body 18, and the mounting groove 22 is used to install a heat insulation board 21. The heat insulation board 21 is used to prevent heat leakage from this end of the heating device 16. Because this end of the heating device 16 is exposed outside the lower heating module, heat insulation treatment is required.

[0065] In this embodiment, if Figure 4 As shown, the porous plate three 13 is located inside the lower furnace 12. This design makes it convenient to place the product to be heated on the porous plate three 13 to avoid the product being blocked by the porous plate two 11.

[0066] In this embodiment, the fan 9 adopts a backward-inclined impeller with high heat exchange efficiency. The power curve of the fan 9 is not overloaded, and the power curve is mainly concentrated in the normal range, which can reach a very large value and is not easy to overload. Secondly, the blades and impellers of the equipment have high structural strength and can adapt to high static pressure systems. The backward-inclined centrifugal fan can ensure a large air volume during normal operation with very little noise, and will not cause much impact on the on-site environment.

[0067] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A heating module, characterized in that: It comprises an upper heating module and a lower heating module, wherein the upper heating module has: Outer shell one; An inner shell body 1 is arranged in the outer shell body 1 and is spaced apart from the outer shell body 1, so as to define an air outlet 1 between the outer shell body 1 and the inner shell body 1, and the lower ends of the outer shell body 1 and the inner shell body 1 are open; The fan is arranged at the upper ends of the outer shell 1 and the inner shell 1, and is detachably sealed and fixedly connected to the outer shell 1 and the inner shell 1. After the fan is started, the fan draws external air from bottom to top into the air passage 1, and then the fan injects the air in the air passage 1 into the interior of the inner shell 1 from top to bottom; An air filling tube, one end of which is located outside the outer shell, and the other end of which passes through the outer shell and is connected to the airway; A temperature detection device, which passes through the outer shell 1 and the inner shell 1 and is used to detect the air temperature inside the inner shell 1; The lower heating module comprises: The second outer shell has an open upper end and is detachably sealed and fixedly connected to the lower end of the first outer shell; The second partition plate is disposed at two opposite ends of the second outer shell and is spaced apart from two opposite inner side walls of the second outer shell, so that a second airway is defined between the second partition plate and the inner side wall of the second outer shell, the upper end of the second airway is connected to the lower end of the first airway, and the upper end of the second partition plate is detachably sealed and fixedly connected to the lower end of the first inner shell; The porous plate 3 is arranged between the two partition plates 2 at the upper end of the outer shell 2, and the airflow in the inner shell 1 flows downward into the lower furnace body and passes through the porous plate 3 and then continues to flow downward; The partition plate 1 is arranged below the porous plate 3 in the outer shell 2 and is spaced apart from the inner bottom surface of the outer shell 2. The partition plate 1 is provided with a vent. The area between the partition plate 1 and the inner bottom surface of the outer shell 2 is connected to the lower end of the airway 2. The heating device is arranged between the partition plate 1 and the inner bottom surface of the outer shell 2. The airflow passing through the porous plate 3 continues to flow downward through the vent and enters between the partition plate 1 and the inner bottom surface of the outer shell 2.

2. A heating module according to claim 1, characterized in that: A porous plate 1 is arranged in the inner shell 1, and the porous plate 1 is located directly below the fan. The airflow blown by the fan hits the upper surface of the porous plate 1, and then the airflow passes through the porous plate 1 and flows downward.

3. A heating module according to claim 2, characterized in that: A porous plate 2 is arranged at the open lower end of the inner shell 1. The airflow passing through the porous plate 1 continues to flow downward, passes through the porous plate 2, and then enters the lower furnace body. The airflow passing through the porous plate 2 and then entering the lower furnace body continues to flow downward, passes through the porous plate 3.

4. A heating module according to claim 1, characterized in that: The heating device is detachably plug-in and sealedly connected to the second outer shell.

5. A heating module as claimed in claim 4, characterized in that: One end of the heating device is located on the outer side of the second outer shell, and a second heat insulation board is arranged at one end of the heating device.

6. A heating module according to claim 1, characterized in that: The porous plate three is located inside the outer shell two.

7. A reflow oven, characterized in that: It comprises a lower furnace body and an upper furnace body, the upper furnace body comprises an upper furnace chamber and an upper heating module arranged in the upper furnace chamber, the lower furnace body comprises a lower furnace chamber and a lower heating module arranged in the lower furnace chamber, the upper furnace chamber and the lower furnace chamber are detachably sealed and fixedly connected, and the upper heating module and the lower heating module are the upper heating module and the lower heating module in the heating module of any one of claims 1 to 6.

8. A reflow oven as claimed in claim 7, characterized in that: The outer shell is fixedly connected to the inner wall of the upper furnace; The lower end of the upper furnace is open; The fan is arranged at the upper end of the outer shell 1, the inner shell 1 and the upper furnace, and is detachably and sealedly fixedly connected with the outer shell 1, the inner shell 1 and the upper furnace; One end of the inflation pipe is located outside the upper furnace, and the other end passes through the upper furnace and the outer shell and is connected to the airway; The temperature detection device passes through the upper furnace, outer shell 1 and inner shell 1, and is sealed and fixedly connected to the upper furnace; A heat insulation board 1 is filled between the outer shell 1 and the inner wall of the upper furnace.

9. A reflow oven as claimed in claim 7, characterized in that: The second outer shell is fixedly connected to the inner wall of the lower furnace; The upper end of the lower furnace is open; The porous plate three is located inside the lower furnace.

10. A reflow oven as claimed in claim 7, characterized in that: Sealing strips are sandwiched between the lower end surface of the upper furnace and the upper end surface of the lower furnace, between the upper end surface of the second outer shell and the lower end surface of the first outer shell, and between the lower end surface of the first inner shell and the upper end surface of the second partition.

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