Reflow furnace using liquid nitrogen for cooling and cooling method thereof

Abstract

The invention discloses a reflow oven using liquid nitrogen for cooling and a cooling method thereof.The reflow oven using liquid nitrogen for cooling comprises an oven body and a partition plate arranged in the oven body, the interior of the oven body is divided into an upper space and a lower space by the partition plate, the upper space is an upper cavity, and the lower space is a lower cavity; a conveying line body and a draught fan are arranged in the upper cavity, and the draught fan is located above the conveying line body. A gasifier is arranged in the lower cavity and communicated with the liquid nitrogen container, an air channel is formed in the furnace body, and the two ends of the air channel face the gasifier and the draught fan. The liquid nitrogen cooling device has the beneficial effects that liquid nitrogen at the temperature of minus 196 DEG C is used for replacing conventional ice water at the temperature of 5 DEG C to cool welded products and tools, compared with the ice water at the temperature of 5 DEG C, the liquid nitrogen cooling speed is high, the efficiency is high, the cooling effect is greatly improved, the cooling requirements of the welded products and the tools are effectively met, and additional cooling stations do not need to be added on a product line.

Description

Technical Field

[0001] The invention relates to the field of reflow furnaces, and in particular to a reflow furnace utilizing liquid nitrogen for cooling and a cooling method thereof. Background Art

[0002] In surface mount technology, reflow ovens are used to solder electronic components to printed circuit boards. Nitrogen needs to be filled during soldering to prevent oxidation of the product and solder. After soldering, the product needs to be quickly cooled to solidify the solder and reduce the product temperature to meet the requirements of subsequent processes.

[0003] Existing methods of cooling products mostly use water chillers, which provide cold water at a minimum of 5 degrees. For welding products with tooling, because the tooling absorbs a large amount of additional heat energy during welding, which is dozens or even hundreds of times that of the product, the demand for cooling after welding is more stringent, and the 5-degree cold water provided by the water chiller is difficult to meet the cooling needs. Therefore, some product lines with tooling need to add additional cooling stations to meet the cooling needs of welding products and tooling, but this adds extra expenses, increases cooling costs, and takes up space. Summary of the invention

[0004] The main purpose of the present invention is to provide a reflow furnace using liquid nitrogen for cooling and a cooling method thereof, aiming to solve the problem in the prior art that cold water is difficult to meet the cooling requirements of welding products and tooling.

[0005] In order to solve the above problems, the present invention proposes a reflow furnace using liquid nitrogen for cooling, comprising a furnace body and a partition arranged in the furnace body, wherein the partition divides the furnace body into two spaces, the upper space being an upper chamber and the lower space being a lower chamber;

[0006] The upper chamber is provided with a conveyor line body and a fan, and the fan is located above the conveyor line body;

[0007] A vaporizer is provided in the lower chamber, and the vaporizer is connected to a liquid nitrogen container. An air duct is provided inside the furnace body, and both ends of the air duct face the vaporizer and the fan. After the fan is started, the air around the vaporizer is sucked into the air duct, and the fan blows the air in the air duct toward the conveying line body. The air passing through the conveying line body flows toward the vaporizer and is finally sucked into the air duct again.

[0008] In one embodiment, the partition is provided with ventilation holes, and the air passing through the conveying line body passes through the ventilation holes and flows toward the gasifier.

[0009] In one embodiment, a mesh plate is provided in the upper chamber, the mesh plate is located above the conveying line body, the fan is located above the mesh plate, and the gas blown by the fan passes through the mesh plate and blows toward the conveying line body.

[0010] In one embodiment, the vaporizer is connected to the liquid nitrogen container through a liquid inlet pipe, and the gas outlet pipe of the vaporizer extends to the heating zone in the reflow furnace.

[0011] In one embodiment, a mounting hole is provided on the outer wall of the furnace body of the lower chamber, and the mounting hole is a through hole. Both ends of the gasifier are plugged into and installed in the mounting hole. A sealing plate is detachably sealed in the mounting hole, and the sealing plate is flush with the outer wall of the furnace body.

[0012] In one embodiment, the air channel is in an n-shape, both ends of the air channel are connected to the mounting hole, and the middle of the air channel is connected to the upper chamber.

[0013] In one embodiment, installation gaps are left between the two ends of the gasifier and the installation hole.

[0014] In one embodiment, the gasifier is located directly below the fan and the vent.

[0015] In addition, the present invention also proposes a cooling method of a reflow furnace using liquid nitrogen for cooling, wherein any of the above-mentioned reflow furnaces using liquid nitrogen for cooling is used to perform the following steps:

[0016] Start the fan, the air below the vaporizer is sucked into the airway, rises along the airway, and then enters the upper part of the fan in the upper chamber. The fan blows the air downward to form an airflow, which passes through the conveying line and the vaporizer from top to bottom, and is finally sucked into the airway again, forming a circular flow;

[0017] Open the liquid nitrogen container and transport the liquid nitrogen into the vaporizer through the liquid inlet pipe. The liquid nitrogen exchanges heat with the airflow around the vaporizer, thereby cooling the airflow and vaporizing and heating the liquid nitrogen. Finally, the high-temperature nitrogen flows out of the gas outlet pipe of the vaporizer and enters the heating zone in the reflow furnace.

[0018] The cooled airflow rises along the airway into the upper chamber, and is then blown toward the conveyor body by the fan to cool the welding products and tooling on the conveyor body.

[0019] Beneficial effect: The technical solution of the present application uses liquid nitrogen at minus 196 degrees to replace conventional 5-degree ice water to cool welding products and tooling. Compared with 5-degree ice water, liquid nitrogen has a fast cooling speed and high efficiency, and the cooling effect is greatly improved, which effectively meets the cooling needs of welding products and tooling, and there is no need to add additional cooling stations on the product line. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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.

[0021] Figure 1 This is a schematic diagram of the structure of a reflow furnace using liquid nitrogen for cooling. Figure 1 ;

[0022] Figure 2 This is a schematic diagram of the structure of a reflow furnace using liquid nitrogen for cooling. Figure 2 ;

[0023] Figure 3 yes Figure 1 Schematic diagram after removing the sealing plate;

[0024] Figure 4 yes Figure 3 A magnified view of part A in FIG.

[0025] Figure 5 yes Figure 3 A magnified view of part B in FIG.

[0026] Figure 6 The internal structure diagram of a reflow furnace utilizing liquid nitrogen for cooling is shown in the present invention.

[0027] The following are the descriptions of the reference numerals:

[0028] 1. Furnace body; 2. Partition; 3. Upper chamber; 4. Lower chamber; 5. Gasifier; 6. Mounting hole; 7. Airway; 8. Mesh plate; 9. Motor; 10. Fan; 11. Conveyor line; 12. Air vent; 13. Liquid inlet pipe; 14. Liquid nitrogen container; 15. Sealing plate; 16. Mounting gap. DETAILED DESCRIPTION

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] The present invention proposes a reflow furnace that uses liquid nitrogen for cooling. The reflow furnace uses liquid nitrogen at minus 196 degrees to replace conventional 5-degree ice water to cool welding products and tooling. Compared with 5-degree ice water, liquid nitrogen has a fast cooling speed and high efficiency, and the cooling effect is greatly improved, which effectively meets the cooling needs of welding products and tooling, and there is no need to add additional cooling stations on the product line.

[0034] Specifically, Figure 1-Figure 3 As shown, the reflow furnace using liquid nitrogen for cooling includes a furnace body 1 and a partition 2 arranged in the furnace body 1, and the partition 2 divides the furnace body 1 into two spaces, the upper space is an upper chamber 3, and the lower space is a lower chamber 4.

[0035] In this embodiment, the furnace body 1 is the rear furnace body 1 of the reflow furnace, which is mainly used for cooling the welding products and tooling. The middle furnace body 1 of the reflow furnace is provided with a heating zone for heating the welding products to complete welding. The front furnace body 1 of the reflow furnace is used for feeding and preheating the welding products and tooling.

[0036] In this embodiment, if Figure 1-Figure 3 , Figure 6 As shown, a conveyor line body 11 and a fan are provided in the upper chamber 3 . The fan is located above the conveyor line body 11 . The conveyor line body 11 is used to drive the tooling and the welding products on the tooling to move horizontally in the furnace body 1 .

[0037] Preferably, Figure 1 and Figure 3 As shown, a mesh plate 8 is provided in the upper chamber 3, and the mesh plate 8 is located above the conveyor line body 11. The fan is located above the mesh plate 8. With this design, the mesh plate 8 can be used to cover and protect the fan to avoid the fan being exposed to the outside. The fan includes a motor 9 and a fan 10. The fan 10 is very dangerous during high-speed rotation, and the mesh plate 8 is needed to cover and protect it to ensure safety. The low-temperature gas blown by the fan flows downward, passes through the mesh plate 8 and blows toward the conveyor line body 11, and the tooling transported by the conveyor line body 11 and the welding products on the tooling are cooled by blowing.

[0038] Preferably, the tooling and the welding products on the tooling are transported by the conveyor line 11 to just below the fan, so that the low-temperature gas blown by the fan can act on the tooling and the welding products on the tooling in the shortest time, thereby improving the cooling efficiency.

[0039] In this embodiment, if Figure 1-Figure 3 , Figure 6 As shown, a vaporizer 5 is provided in the lower chamber 4, and the vaporizer 5 is connected to a liquid nitrogen container 14 through a liquid inlet pipe 13. Liquid nitrogen in the liquid nitrogen container 14 flows into the vaporizer 5 through the liquid inlet pipe 13 to perform heat exchange with the air around the vaporizer 5, so that the air around the vaporizer 5 is cooled, and the liquid nitrogen is vaporized and heated. Figure 6 As shown, an air duct 7 is provided inside the furnace body 1, and both ends of the air duct 7 face the gasifier 5 and the fan. After the fan is started, the low-temperature air around the gasifier 5 is sucked into the air duct 7, and the fan blows the low-temperature air in the air duct 7 toward the conveyor line body 11, and the tooling and the welding products on the tooling conveyed by the conveyor line body 11 are cooled by blowing. The hot air passing through the conveyor line body 11 flows toward the gasifier 5, and then exchanges heat with the gasifier 5, and the air is cooled again. Finally, the low-temperature air is sucked into the air duct 7 again, thereby realizing air circulation and cooling of the tooling and the welding products on the tooling.

[0040] In this embodiment, if Figure 2As shown, the partition plate 2 is provided with an air vent 12 , and the hot air passing through the conveying line body 11 flows downward through the air vent 12 and flows toward the gasifier 5 .

[0041] Furthermore, the vaporizer 5 is connected to the liquid nitrogen container 14 through the liquid inlet pipe 13, and the gas outlet pipe of the vaporizer 5 extends to the heating zone in the reflow furnace. With this design, after the liquid nitrogen is vaporized and heated, the high-temperature nitrogen flows out from the gas outlet pipe of the vaporizer 5 into the heating zone to heat the welding products on the tooling. With this design, the power consumption of the heating device in the heating zone can be reduced, which is beneficial to reducing the energy consumption of the reflow furnace.

[0042] Specifically, in this embodiment, if Figure 1-Figure 3 As shown, the outer wall of the furnace body 1 of the lower chamber 4 is provided with a mounting hole 6, the mounting hole 6 is a through hole, and both ends of the gasifier 5 are plugged and installed in the mounting hole 6. A sealing plate 15 is detachably sealed and installed in the mounting hole 6, and the sealing plate 15 is flush with the outer wall of the furnace body 1. The setting of the sealing plate 15 can prevent the low-temperature air in the mounting hole 6 from leaking out of the reflow furnace, as shown in FIG. Figure 1-Figure 6 As shown, the air duct 7 is n-shaped, and both ends of the air duct 7 are connected to the mounting hole 6, and the middle part of the air duct 7 is connected to the upper chamber 3. An installation gap 16 is left between the two ends of the vaporizer 5 and the mounting hole 6 to facilitate the entry of low-temperature air into the mounting hole 6. After the fan is started, the low-temperature air below the vaporizer 5 enters the mounting hole 6 through the installation gap 16, and then the low-temperature air flows upward into the air duct 7. The setting of the sealing plate 15 can prevent the low-temperature air in the mounting hole 6 from leaking out of the reflow furnace. The furnace body 1 is sealed and connected to the ground during installation, so the low-temperature air in the furnace body 1 will not leak out of the reflow furnace. The low-temperature air enters the upper part of the fan 10 in the upper chamber 3 from the middle part of the air duct 7, and then is blown downward by the fan 10 to flow to the conveying line body 11 to blow and cool the tooling and the welding products on the tooling transported by the conveying line body 11. Finally, the hot air passes through the vent 12 and enters the vaporizer 5 to exchange heat with the vaporizer 5 to form low-temperature air again. The airflow direction in the furnace body 1 is as shown in FIG. Figure 6 Indicated by the arrow.

[0043] Preferably, the gasifier 5 is located directly below the fan and the vent 12. With this design, the gasifier 5 can quickly cool down the hot air flowing downward through the vent 12, thereby improving the operating efficiency.

[0044] In addition, the present invention also proposes a cooling method of a reflow furnace using liquid nitrogen for cooling, wherein any of the above-mentioned reflow furnaces using liquid nitrogen for cooling is used to perform the following steps:

[0045] S1, start the fan, such as Figure 6As shown, the low-temperature air below the vaporizer 5 flows in the direction indicated by the arrow and is sucked into the air passage 7, and rises along the air passage 7, and then enters the upper part of the fan in the upper chamber 3. The fan blows the low-temperature air downward to form a low-temperature airflow flowing downward. The low-temperature airflow passes through the conveying line 11 and the vaporizer 5 from top to bottom in sequence, and is finally sucked into the air passage 7 again, forming a circulating flow.

[0046] S2, open the liquid nitrogen container 14, and transport the liquid nitrogen into the vaporizer 5 through the liquid inlet pipe 13. The liquid nitrogen exchanges heat with the airflow around the vaporizer 5, thereby cooling the airflow and vaporizing and heating the liquid nitrogen. Finally, the high-temperature nitrogen flows out from the outlet pipe of the vaporizer 5 into the heating zone in the reflow furnace to heat the welded products on the tooling, so as to reduce the power consumption of the heating device in the heating zone, which is conducive to reducing the energy consumption of the reflow furnace;

[0047] S3. The cooled airflow rises along the air passage 7 and enters the upper chamber 3, and is then blown toward the conveyor line body 11 by the fan to cool the welding products and tooling on the conveyor line body 11.

[0048] The reflow furnace of this embodiment uses liquid nitrogen at minus 196 degrees to replace conventional 5-degree ice water to cool welding products and tooling. Compared with 5-degree ice water, liquid nitrogen has a fast cooling speed and high efficiency, and the cooling effect is greatly improved, effectively meeting the cooling needs of welding products and tooling, without adding additional cooling stations on the product line.

[0049] 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 reflow furnace using liquid nitrogen for cooling, It is characterized in that It includes a furnace body and a partition plate arranged in the furnace body, wherein the partition plate divides the furnace body into two spaces, the upper space is an upper chamber, and the lower space is a lower chamber; The upper chamber is provided with a conveyor line body and a fan, and the fan is located above the conveyor line body; A vaporizer is provided in the lower chamber, and the vaporizer is connected to a liquid nitrogen container. An air duct is provided inside the furnace body, and both ends of the air duct face the vaporizer and the fan. After the fan is started, the air around the vaporizer is sucked into the air duct, and the fan blows the air in the air duct toward the conveying line body. The air passing through the conveying line body flows toward the vaporizer and is finally sucked into the air duct again.

2. A reflow furnace using liquid nitrogen for cooling as claimed in claim 1, It is characterized in that The partition is provided with ventilation holes, and the air passing through the conveying line body flows through the ventilation holes to the gasifier.

3. A reflow furnace using liquid nitrogen for cooling as claimed in claim 1, It is characterized in that A mesh plate is arranged in the upper chamber, the mesh plate is located above the conveying line body, the fan is located above the mesh plate, and the gas blown by the fan passes through the mesh plate and blows toward the conveying line body.

4. A reflow furnace using liquid nitrogen for cooling as claimed in claim 1, It is characterized in that The vaporizer is connected to the liquid nitrogen container through a liquid inlet pipe, and the gas outlet pipe of the vaporizer extends to the heating zone in the reflow furnace.

5. A reflow furnace using liquid nitrogen for cooling as claimed in claim 1, It is characterized in that The outer wall of the furnace body of the lower chamber is provided with a mounting hole, the mounting hole is a through hole, both ends of the gasifier are plugged and installed in the mounting hole, a sealing plate is detachably sealed and installed in the mounting hole, and the sealing plate is flush with the outer wall of the furnace body.

6. A reflow furnace using liquid nitrogen for cooling as claimed in claim 5, It is characterized in that The air channel is in an N-shape, both ends of the air channel are communicated with the mounting hole, and the middle part of the air channel is communicated with the upper chamber.

7. A reflow furnace using liquid nitrogen for cooling as claimed in claim 5, It is characterized in that There are installation gaps between the two ends of the gasifier and the installation holes.

8. A reflow furnace using liquid nitrogen for cooling as claimed in claim 2, It is characterized in that The gasifier is located directly below the fan and the vent.

9. A method for cooling a reflow furnace using liquid nitrogen. It is characterized in that The following steps are performed using a reflow furnace using liquid nitrogen cooling as claimed in any one of claims 1 to 8: Start the fan, the air below the vaporizer is sucked into the airway, rises along the airway, and then enters the upper part of the fan in the upper chamber. The fan blows the air downward to form an airflow, which passes through the conveying line and the vaporizer from top to bottom, and is finally sucked into the airway again, forming a circular flow; Open the liquid nitrogen container and transport the liquid nitrogen into the vaporizer through the liquid inlet pipe. The liquid nitrogen exchanges heat with the airflow around the vaporizer, thereby cooling the airflow and vaporizing and heating the liquid nitrogen. Finally, the high-temperature nitrogen flows out of the gas outlet pipe of the vaporizer and enters the heating zone in the reflow furnace. The cooled airflow rises along the airway into the upper chamber, and is then blown toward the conveyor body by the fan to cool the welding products and tooling on the conveyor body.

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