WO2023164343A1

WO2023164343A1 - Exhaust gas purification system

Info

Publication number: WO2023164343A1
Application number: PCT/US2023/061277
Authority: WO
Inventors: Shenghu YAN
Original assignee: Illinois Tool Works Inc.
Priority date: 2022-02-28
Filing date: 2023-01-25
Publication date: 2023-08-31
Also published as: CN116688705A

Abstract

The present application provides an exhaust gas purification system for a reflow furnace comprising: a filtration device that receives exhaust gas from the reflow furnace chamber, cools, filters and purifies the exhaust gas, and outputs primary purified gas; an adsorption device in fluid communication with the filtration device, adsorbs and purifies the primary purified gas from the filtration device, outputs the secondary purified gas, and delivers the secondary purfied gas to the chamber. The present application adds an adsorption device for absorbing contaminants remaining in the exhaust gas due to insufficient cooling temperatures in the filtration device, so as to reduce improvement costs while increasing the removal efficiency of contaminants and extending the maintenance time of the work area. The present application also adds a heating device for desorption of the saturated adsorption device such that the adsorption device can be reused.

Description

Exhaust Gas Purification System

Technical Field

[0001] The present application relates to an exhaust gas purification system, and in particular to an exhaust gas purification system in a reflow furnace for purifying exhaust gas in the reflow furnace.

Background

[0002] In the production of printed circuit boards, electronic elements are typically mounted to circuit boards using a process called “reflow soldering”. In a typical reflow soldering process, a soldering paste (e.g., tin paste) is deposited into a selected area on a circuit board and a wire of one or more electronic elements is inserted into the deposited soldering paste. The circuit board then passes through a reflow furnace in which the solder paste refluxes in a heating area (i.e., is heated to a melting or reflux temperature) and then cools in a cooling area to electrically and mechanically connect the wires of the electronic components to the circuit board. As used herein, the term “circuit board” comprises a substrate assembly of any type of electronic element, such as comprises a wafer substrate. In the reflow furnace, air or inert gas (e.g. nitrogen) is typically used as the working gas, and different working gases are used for circuit boards with different process requirements. The working gas is filled in the reflow furnace chamber, and the circuit board is welded in the working gas as it is conveyed through the chamber via the conveyor.

Summary

[0003] Solder paste include not only the solder, but also the flux that make the solder wet and provide good welding seams. Other additives such as solvents and catalysts may also be included. After the solder paste is deposited on the circuit board, the circuit board is conveyed via the conveyor to pass through multiple heating areas in the reflow furnace. The heat in the heating area melts solder paste and organic compounds that mainly include fluxes so that volatile organics (“VOCs”) are vaporized to form vapors and “contaminants”. These contaminants mix with the working gas in the heating area to form exhaust gases. Accumulation of these contaminants in the reflow furnace can cause certain problems. For example, as the circuit board is transported from the heating area to the cooling area, contaminants also flow to the cooling area, where they are condensated into liquid and/or solid onto the circuit board after cooling, thus contaminating the circuit board and necessitating subsequent cleaning steps. In addition, condensate may also drip onto subsequent circuit boards, which may damage the components on the circuit boards or necessitate subsequent cleaning steps of the contaminated circuit boards.

[0004] Therefore, it is desirable to purify the exhaust gas containing contaminants in the reflow furnace chamber (e.g., heating and cooling areas) to keep a clean working atmosphere in the reflow furnace chamber, thereby preventing contaminants from entering the reflow furnace cooling area to cause the above problems in the reflow furnace.

[0005] When the reflow furnace operates with a substantially inert gas (e.g. nitrogen) as the working gas, it is generally desirable that exhaust gases discharged from the reflow furnace be treated clean by the exhaust gas purification system before being transported back to the reflow furnace for reuse due to the high price of the substantially inert gas (e.g. nitrogen). When the reflow furnace uses air as the working gas, the exhaust gas discharged from the reflow furnace can be directly discharged to the atmosphere after being treated with the exhaust gas purification system, or can be transported back to the reflow furnace for reuse.

[0006] In prior art’s exhaust gas purification system, exhaust gas generated in the heating area of the reflow furnace is pumped out to a filtration device for cooling and filtering to remove contaminants (e.g., flux constituents) from the exhaust gas to obtain the purified gas, which is then transported to the heating and cooling areas for recycling.

[0007] Upon observation and investigation, the Applicant found that the exhaust gas pumped out from the heating area of the reflow furnace and into the filtration device included a variety of flux constituents, and the removal efficiency of the filtration device was different for different flux constituents. For some flux constituents, the removal efficiency of the filtration device is very low, which even cannot be removed. When the content of the flux constituents in the cooling area reaches a predetermined threshold, maintenance is required on the cooling area, e.g., shutdown to clean the cooling area. In the case of the same amount of volatilized contaminants (e.g., flux constituents), if the removal efficiency of certain flux constituents by the filtration device is very low, the “purified” gas outputted by the filtration device will contain a great number of unremoved flux constituents, and the “purified” gas recycled and inputted to the heating and cooling areas will result in more flux constituents that are not removed in this area, thereby significantly reducing the maintenance time of the cooling area and even much lower than the uniform maintenance time of the entire system. The cooling area in the entire system needs to be maintained separately at this time, which can lead to increased maintenance costs for the entire system. Each device/unit in the entire system needs to be maintained approximately at the same time to reduce maintenance costs.

[0008] When finding a solution to improve the removal efficiency of the filtration device to extend the maintenance time of the cooling area, the Applicant found that the low removal efficiency of the filtration device may be caused by insufficient cooling temperature, but the costs would be too high if the removal efficiency is improved by further reducing the cooling temperature. In addition, the flux constituents generally do not account for a high proportion (low concentration) of the exhaust gas, so the cooling temperature required for improving the removal efficiency of the filtration device needs to be further reduced, thus further increasing the costs of improvement. For example, the filtration device may condense some of the organics in the flux, including organics like rosin, alcohols, acids, esters, or ether organics, at a cooling temperature of 40°C-50°C. However, some of the organics in the flux (e.g., N-methylpiperidine) have a lower condensation temperature, which, when lower than 0°C, could result in too high improvement costs by lowering the cooling temperature of the filtration device.

[0009] In order to address at least one of the above problems, the present application provides an exhaust gas purification system such that improvement costs are reduced while increasing the removing efficiency of contaminants to extend the maintenance time of the work area.

[0010] To achieve the above goals, a first aspect of the present application provides an exhaust gas purification system for a reflow furnace, wherein the exhaust gas purification system comprises: a filtration device and a first adsorption device in fluid communication with the filtration device. The filtration device receives exhaust gas from the chamber of the reflow furnace for cooling, filtering, and purifying the exhaust gas and outputting a primary purified gas. The first adsorption device is used for adsorbing and purifying the primary purified gas from the filtration device and outputting and transporting the secondary purified gas to the reflow furnace chamber.

[0011] According to the first aspect described above, the exhaust gas purification system further comprises: a heating device, the first adsorption device being controllably in alternating fluid communication with the filtration device and the heating device, wherein: (i) the first adsorption device performs an adsorption operation when it is in fluid communication with the filtration device, and (ii) the first adsorption device performs a desorption operation when it is in fluid communication with the heating device.

[0012] According to the first aspect described above, the heating device is used for heating air entering the heating device and outputting the heated air to the first adsorption device. The heated air desorbs the first adsorption device in a saturated state or an approximately saturated state such that the first adsorption device in a saturated state or an approximately saturated state returns to the operating state.

[0013] According to the first aspect described above, the filtration device comprises: Cooling unit and filtering unit. The cooling unit is used for receiving and cooling the exhaust gas from the reflow furnace chamber so that some of the contaminants in the exhaust gas are condensed, and the cooled and purified exhaust gas is outputted. The filtering unit is used for receiving the cooled and purified exhaust gas from the cooling unit, filtering the liquids and/or solids mixed in the cooled and purified exhaust gas, and outputting the primary purified gas.

[0014] According to the first aspect described above, the cooling temperature range of the filtration device for cooling the exhaust gas includes 40°C-50°C.

[0015] According to the first aspect described above, the reflow furnace chamber comprises a heating area and a cooling area, wherein the filtration device receives the exhaust gas from the heating area of the reflow furnace chamber and the first adsorption device is used for transporting the secondary purified gas to the heating area and/or the cooling area of the reflow furnace chamber.

[0016] According to the first aspect described above, the exhaust gas purification system further comprises: a valve assembly for controlling alternating fluid communication of the first adsorption device with the filtration device and the heating device. The valve assembly includes a first valve and a second valve. The first valve is used for controlling fluid communication or disconnection of the filtration device and the first adsorption device. The second valve is used for controlling fluid communication or disconnection of the heating device and the first adsorption device.

[0017] According to the first aspect described above, the first adsorption device comprises a first adsorption material for adsorbing contaminants in the primary purified gas from the filtration device to the surface and/or interior of the first adsorption material for adsorption operations.

[0018] According to the first aspect described above, the heated air entering the first adsorption device from the heating device heats the contaminants adsorbed in the first adsorption device to discharge these contaminants out of the first adsorption device, thereby causing the first adsorption device to desorb.

[0019] The present application adds an adsorption device for absorbing contaminants remaining in the exhaust gas in the filtration device due to insufficient cooling temperature. The present application also adds a heating device for desorbing the saturated adsorption device so that the adsorption device can be reused.

[0020] Specifically, the adsorption device may absorb flux that cannot be cooled off at its set temperature by the filtration device, thereby avoiding the reduction of the amount of flux in the exhaust gas by further reducing the cooling temperature of the filtration device to lower the removal costs. In addition, since the adsorption device is in a saturated state when too many contaminants (e.g., flux) are adsorbed in the adsorption device, in order for the adsorption device to no longer be in a saturated state, the heating device provides hot air such that the adsorption device desorbs to remove the adsorbed contaminants from the adsorption device, thereby returning the adsorption device to a working state and avoiding being in a saturated state.

[0021] On the basis of the first aspect of the present application, the exhaust gas purification system provided in the second aspect of the present application further comprises: a second adsorption device controllably in alternating fluid communication with the filtration device and the heating device. The second adsorption device is used for adsorbing and purifying the primary purified gas from the filtration device, outputting and transporting the secondary purified gas to the reflow furnace chamber, wherein (i) when the first adsorption device is in fluid communication with the heating device, the second adsorption device is in fluid communication with the filtration device, at which point the first adsorption device is performing a desorption operation and the second adsorption device is performing an adsorption operation; and (ii) when the first adsorption device is in fluid communication with the filtration device, the second adsorption device is in fluid communication with the heating device, at which point the first adsorption device is performing an adsorption operation and the second adsorption device is performing a desorption operation.

[0022] According to the second aspect described above, (i) the first adsorption device is in a saturated state or an approximately saturated state when the first adsorption device is in fluid communication with the heating device; and (ii) the second adsorption device is in a saturated state or an approximately saturated state when the second adsorption device is in fluid communication with the heating device.

[0023] According to the second aspect described above, the heating device is used for heating the air received that enters the heating device and outputting the heated air to the second adsorption device. The heated air desorbs the second adsorption device in a saturated state or an approximately saturated state such that the second adsorption device in a saturated state or an approximately saturated state returns to the operating state.

[0024] According to the second aspect described above, the reflow furnace chamber comprises a heating area and a cooling area, wherein the filtration device receives exhaust gas from the heating area of the reflow furnace chamber and the second adsorption device is used for transporting the secondary purified gas to the heating area and/or the cooling area of the reflow furnace chamber.

[0025] According to the second aspect described above, the filtration device is configured to be in controllably fluid communication with one of the first and second adsorption devices, and the heating device is configured to be in controllably fluid communication with the other of the first and second adsorption devices. [0026] According to the second aspect described above, the exhaust gas purification system further comprises: a first valve assembly and a second valve assembly. The first valve assembly is used for controlling fluid communication of the filtration device with one of the first and second adsorption devices. The second valve assembly is for controlling the fluid communication of the heating device with one of the first and second adsorption devices.

[0027] According to the second aspect described above, the first valve assembly includes a first valve for controlling fluid communication or disconnection of the filtration device with the first adsorption device and a third valve for controlling fluid communication or disconnection of the filtration device with the second adsorption device. The second valve assembly includes a second valve for controlling fluid communication or disconnection of the heating device with the first adsorption device and a fourth valve for controlling fluid communication or disconnection of the heating device with the second adsorption device.

[0028] According to the second aspect described above, the second adsorption device comprises a second adsorption material for adsorbing contaminants in the primary purified gas from the filtration device to the surface and/or interior of the second adsorption material for adsorption operations.

[0029] According to the second aspect described above, the heated air entering the second adsorption device from the heating device heats the contaminants adsorbed in the second adsorption device to discharge these contaminants out of the second adsorption device, thereby causing the second adsorption device to desorb.

[0030] In order to enable the uninterrupted use of the adsorption device during PCB processing, the present application sets up two adsorption devices for alternating use. Specifically, since the adsorption device is unable to perform an adsorption operation to purify the exhaust gas during desorption, the concentration of contaminants in the cooling area of the reflow furnace chamber is increased. The addition of the second adsorption device allows the first adsorption device to still perform an adsorption operation when the first adsorption device is desorbed, so that at least one adsorption device is maintained for adsorption operations and the entire system can also function normally during desorption. [0031] The concepts, specific structures, and technical effects of the present application will be further explained below in conjunction with the appended drawings to fully understand the purpose, features, and effects of the present application.

Brief Description of Drawings

[0032] Fig. 1 shows a simplified block diagram of an exhaust gas purification system 100 according to a first example of the present application;

[0033] Fig. 2 shows a simplified block diagram of an exhaust gas purification system 200 according to a second example of the present application;

[0034] Fig. 3A shows a structural schematic diagram of one example of a filtration device 103 in the exhaust gas purification systems 100 and 200 of Figs. 1 and 2;

[0035] Fig. 3B is a top view of the filtration device 103 shown in Fig. 3A;

[0036] Fig. 3C is a structural schematic diagram of the filtration device 103 shown in Fig. 3A that removes the top 304, the left 305, the right 306, and the rear 308 of the housing (retaining the front 307 and the bottom of the housing);

[0037] Fig. 3D is a left view of the filtration device 103 shown in Fig. 3C;

[0038] Fig. 3E is a right view of the filtration device 103 shown in Fig. 3C;

[0039] Fig. 3F is a top view of the filtration device 103 shown in Fig. 3C;

[0040] Fig. 3G is a bottom view of the filtration device 103 shown in Fig. 3A that removes the bottom of the housing;

[0041] Fig. 4 shows a structural diagram of one example of a heating device 105 in the exhaust gas purification systems 100 and 200 of Figs. 1 and 2;

[0042] Fig. 5A shows a structural schematic diagram of one example of a first adsorption device 104 in the exhaust gas purification systems 100 and 200 of Figs. 1 and 2;

[0043] Fig. 5B is a structural schematic diagram of the first adsorption device 104 shown in Fig. 5A that removes the top;

[0044] Fig. 5C is a front view of the first adsorption device 104 shown in Fig. 5B; and

[0045] FIG. 5D is a top view of the first adsorption device 104 shown in Fig. 5B. Detailed Description

[0046] Various specific embodiments of the present application will be described below with reference to the attached drawings that form a part of the present specification. It should be understood that while terms denoting orientation, such as “front”, “rear”, “upper”, “lower”, “left”, “right”, “top”, “bottom”, “side”, etc., are used in the present application to describe various exemplary structural parts and elements of the present application, these terms are used herein for convenience of illustration only and are determined based on the exemplary orientations shown in the appended drawings. Since the examples disclosed in the present application may be disposed in different orientations, these terms denoting orientation are for illustrative purposes only and should not be considered as limiting.

[0047] Those skilled in the art shall understand that the exhaust gas or gas described in this example refers to an ingredient that is mostly gaseous, which may also comprise a portion of a liquid or solid ingredient.

[0048] Fig. 1 shows a simplified block diagram of the exhaust gas purification system 100 according to a first example of the present application for illustrating connection relationships of various portions of the exhaust gas purification system 100. As shown in Fig. 1 , the exhaust gas purification system 100 is placed outside of the reflow furnace chamber 110 and is connected to the reflow furnace chamber 110. When the reflow furnace uses a substantially inert gas (e.g., nitrogen) as the working gas, the exhaust gas purification system 100 receives the exhaust gas discharged from the reflow furnace chamber 110, purifies the exhaust gases, and transports the purified gas back into the reflow furnace chamber 110.

[0049] As shown in Fig. 1 , the exhaust gas purification system 100 includes a filtration device 103 and a first adsorption device 104, wherein the filtration device 103 and the first adsorption device 104 connect to each other and to the reflow furnace chamber 110 to purify exhaust gas discharged from the reflow furnace chamber 110 and to transport the purified gas back to the reflow furnace chamber 110 for recycling. The filtration device 103 is connected to the reflow furnace chamber 110 and receives exhaust gas from the reflow furnace chamber 110. The filtration device 103 cools, filters, and purifies the received exhaust gas and output a primary purified gas. The first adsorption device 104 is connected to the filtration device 103 and receives the primary purified gas from the filtration device 103. The first adsorption device 104 performs an adsorption operation on the primary purified gas to purify it and output a secondary purified gas, and transports the secondary purified gas to the reflow furnace chamber 110.

[0050] The first adsorption device 104 in the present application is used for absorbing contaminants (e.g., flux) remaining in the exhaust gas in the filtration device 103 due to insufficiently low cooling temperature. Specifically, the first adsorption device 104 may absorb flux that cannot be cooled off and removed at its set temperature by the filtration device 103, thereby avoiding the reduction of the amount of flux in the exhaust gas by further reducing the cooling temperature of the filtration device 103, and lowering the removal costs.

[0051] The exhaust gas purification system 100 also includes a heating device 105, the first adsorption device 104 being controllably in alternating fluid communication with the filtration device 103 and the heating device 105. The exhaust gas purification system 100 further includes a valve assembly for controlling alternating fluid communication of the first adsorption device 104 with the filtration device 103 and the heating device 105. The valve assembly includes a first valve 1061 for controlling fluid communication or disconnection of the first adsorption device 104 with the filtration device 103, and a second valve 1062 for controlling fluid communication or disconnection of the first adsorption device 104 with the heating device 105. The valve assembly, the first valve 1061 , and the second valve 1062 may be operated by a controller to control fluid communication or disconnection of various devices to which they are connected. The valve assembly includes other forms of valve structure. When the first adsorption device 104 is in fluid communication with the filtration device 103, the first adsorption device 104 performs an adsorption operation; when the first adsorption device 104 is in fluid communication with the heating device 105, the first adsorption device 104 performs a desorption operation. When the first adsorption device 104 performs an adsorption operation for a period of time to reach a saturated state or an approximately saturated state, the first adsorption device 104 cannot or is substantially no longer able to adsorb contaminants (e.g., flux) in the exhaust gas into the first adsorption device 104 to purify the exhaust gas. The first adsorption device 104 in the saturated state or approximately saturated state may use the heating device 105 to perform a desorption operation to return to the operating state. The heating device 105 is used for heating the air entering therein and outputting heated air to the first adsorption device 104, which desorbs the first adsorption device 104 in a saturated state or an approximately saturated state such that the first adsorption device 104 in a saturated state or an approximately saturated state returns to the operating state. The heated air entering the first adsorption device 104 from the heating device 105 heats contaminants in the exhaust gas adsorbed in the first adsorption device 104 to discharge the contaminants in the exhaust gas out of the first adsorption device 104, thereby causing the first adsorption device 104 to desorb.

[0052] The heating device 105 in the present application is used for desorbing the first adsorption device 104 in a saturated state or an approximately saturated state such that the first adsorption device 104 can be reused. When the first adsorption device 104 has too many contaminants (e.g., flux) adsorbed in the adsorption operation, the first adsorption device 104 will be in a saturated state and cannot work anymore, that is, no or substantially no adsorption operation can be performed to purify the exhaust gas. Thus, in order to render the first adsorption device 104 no longer saturated, the heating device 105 provides hot air such that the first adsorption device 104 desorbs contaminants adsorbed in the first adsorption device 104 and discharge these contaminants out of the first adsorption device 104, thereby returning the first adsorption device 104 to a working state without being saturated.

[0053] Specifically, as shown in Fig. 1 , the reflow furnace chamber 110 includes a heating area 101 and a cooling area 102, wherein the transfer device first transfers the PCB to the heating area 101 for heating and welding, and then transfers the PCB to the cooling area 102 for cooling. The heating area 101 comprises a first gas inlet 1011 , a second gas inlet 1013, and an exhaust gas outlet 1012, and the cooling area 102 comprises a first gas inlet 1021 and a second gas inlet 1022. The filtration device 103 comprises an exhaust gas inlet 1031 and a gas outlet 1032; the first adsorption device 104 comprises a gas inlet 1041 , a purified gas outlet 1042, an air inlet 1043, and an exhaust gas outlet 1044; the heating device 105 comprises an air inlet 1051 and an air outlet 1052. The first gas inlet 1011 of the heating area 101 and the first gas inlet 1021 of the cooling area 102 are used for receiving nitrogen (N2) to provide a low oxygen environment for the welding of the PCB. The exhaust gas outlet 1012 of the heating area 101 is in fluid communication with the exhaust gas inlet 1031 of the filtration device 103; the gas outlet 1032 of the filtration device 103 is in fluid communication with the gas inlet 1041 of the first adsorption device 104; the purified gas outlet 1042 of the first adsorption device 104 is in fluid communication with the second gas inlet 1013 of the heating area 101 and the second gas inlet 1022 of the cooling area 102. In other examples, the gas outlet 1032 of the filtration device 103 is controllably in fluid communication with the gas inlet 1041 of the first adsorption device 104 through the first valve 1061 , and the purified gas outlet 1042 of the first adsorption device 104 is in fluid communication with the second gas inlet 1013 of the heating area 101 or the second gas inlet 1022 of the cooling area 102. The air inlet 1051 of the heating device 105 is used for receiving air or compressed air, and the air outlet 1052 of the heating device 105 is controllably in fluid communication with the air inlet 1043 of the first adsorption device 104 through the second valve 1062. The exhaust gas outlet 1044 of the first adsorption device 104 is used for discharging exhaust gas generated by the first adsorption device 104 during desorption.

[0054] During the operation, the filtration device 103 receives the exhaust gas from the heating area 101 through the exhaust gas inlet 1031 , cools, filters, and purifies the received exhaust gas, and outputs a primary purified gas through the gas outlet 1032. The filtration device 103 cools and filters the exhaust gas to remove some contaminants from the exhaust gas, thereby outputting the primary purified gas. The filtration device 103 comprises a cooling unit 111 and a filtering unit 112. The cooling unit 111 is used for receiving the exhaust gas from the heating area 101 , and cooling the exhaust gas so that some of the contaminants in the exhaust gas are condensed and the cooled and purified exhaust gas is outputted. The filtering unit 112 is used for receiving the cooled and purified exhaust gas from the cooling unit 111 , filtering out the liquid and/or solid mixed in the cooled and purified exhaust gas, and outputting the primary purified gas.

[0055] When the first adsorption device 104 is performing an adsorption operation, the first valve 1061 controls the gas inlet 1041 of the first adsorption device 104 to be in fluid communication with the gas outlet 1032 of the filtration device 103, and the second valve 1062 controls the air inlet 1043 of the first adsorption device 104 to be fluidly disconnected with the air outlet 1052 of the heating device 105. The first adsorption device 104 receives the primary purified gas from the filtration device 103 through the gas inlet 1041 , performs an adsorption operation on the primary purified gas to purify it, and transports the secondary purified gas to the heating area 101 and/or the cooling area 102 through the purified gas outlet 1042. The heating area 101 receives a secondary purified gas from the first adsorption device 104 through the second gas inlet 1013 to provide a required working environment for welding. The cooling area 102 receives a secondary purified gas from the first adsorption device 104 through the second gas inlet 1022 to provide a required work environment for welding. Since the exhaust gas pumped out of the heating area 101 includes a portion of the nitrogen (N2) received by the heating area 101 from the first gas inlet 1011 , while the filtration device 103 and the first adsorption device 104 do not remove nitrogen (N2) in the purification process, the secondary purified gas purified and outputted by the filtration device 103 and the first adsorption device 104 includes nitrogen(N2), which may be delivered to the heating area 101 and/or the cooling area 102 for recycling.

[0056] When the first adsorption device 104 performs a desorption operation, the first valve 1061 controls the gas inlet 1041 of the first adsorption device 104 to fluidly disconnect with the gas outlet 1032 of the filtration device 103, and the second valve 1062 controls the air inlet 1043 of the first adsorption device 104 to fluidly connect with the air outlet 1052 of the heating device 105. The heating device 105 receives air through the air inlet 1051 , heats the received air, and transports the heated air through the air outlet 1052 to the first adsorption device 104. The first adsorption device 104 in a saturated state or approximately saturated state receives heated air from the heating device 105 through the air inlet 1043, uses the heated air to heat the contaminants in the exhaust gas adsorbed in the first adsorption device 104 to discharge the contaminants out of the first adsorption device 104, thereby returning the first adsorption device 104 in a saturated state or approximately saturated state to the operating state and outputting the exhaust gas through the exhaust gas outlet 1044. In other examples, the heating device 105 may receive compressed air through the air inlet 1051 , such as from a compressor, and heat the received compressed air to output the heated air.

[0057] Fig. 2 shows a simplified block diagram of an exhaust gas purification system 200 according to a second example of the present application for illustrating connection relationships of various portions of the exhaust gas purification system 200. As shown in Fig. 2, the exhaust gas purification system 200 is placed outside the reflow furnace chamber 110 and is connected to the reflow furnace chamber 110. When the reflow furnace uses a substantially inert gas (e.g., nitrogen) as the working gas, the exhaust gas purification system 200 receives the exhaust gas discharged from the reflow furnace chamber 110, purifies the exhaust gas, and transports the purified gas back into the reflow furnace chamber 110.

[0058] In contrast to the exhaust gas purification system 100 shown in Fig. 1 , the exhaust gas purification system 200 shown in Fig. 2 adds a second adsorption device 201 that alternates adsorption and desorption operations with the first adsorption device 104. Specifically, the second adsorption device 201 performs a desorption operation when the first adsorption device 104 performs an adsorption operation; the second adsorption device 201 performs an adsorption operation when the first adsorption device 104 performs a desorption operation. The exhaust gas purification system 200 can be always absorbed by any of the first adsorption device 104 or the second adsorption device 201 , thereby avoiding the inability to operate due to the need for desorption operations, such as the inability to perform adsorption operations to purify exhaust gas. For a single adsorption device, the adsorption operation cannot be performed to purify the exhaust gas during desorption.

[0059] As shown in Fig. 2, the exhaust gas purification system 200 includes a filtration device 103, a heating device 105, a first adsorption device 104, and a second adsorption device 201 . The structures of the filtration device 103, the heating device 105, and the first adsorption device 104 in Fig. 2 are identical to those of the filtration device 103, the heating device 105, and the first adsorption device 104 in Fig. 1 , respectively. The structures of the first adsorption device 104 and the second adsorption device 201 in Fig. 2 are identical. In other examples, the structures of the first adsorption device 104 and the second adsorption device 201 may be different.

[0060] In Fig. 2, the first adsorption device 104 is controllably in fluid communication with the filtration device 103 and the heating device 105 alternately for adsorption and desorption, wherein the first adsorption device 104 is performing an adsorption operation when the first adsorption device 104 is in fluid communication with the filtration device 103 and the first adsorption device 104 is performing a desorption operation when the first adsorption device 104 is in fluid communication with the heating device 105. The second adsorption device 201 is controllably in fluid communication with the filtration device 103 and the heating device 105 alternately for adsorption and desorption, wherein the second adsorption device 201 performs an adsorption operation when the second adsorption device 201 is in fluid communication with the filtration device 103 and the second adsorption device 201 perform a desorption operation when the second adsorption device 201 is in fluid communication with the heating device 105.

[0061] When the first adsorption device 104 is in fluid communication with the filtration device 103, and the second adsorption device 201 is in fluid communication with the heating device 105, the first adsorption device 104 is performing an adsorption operation and the second adsorption device 201 is performing a desorption operation. When the first adsorption device 104 is in fluid communication with the heating device 105, and the second adsorption device 201 is in fluid communication with the filtration device 103, the first adsorption device 104 performs a desorption operation and the second adsorption device 201 performs an adsorption operation. When the first adsorption device 104 is in a saturated state or an approximately saturated state, the first adsorption device 104 is substantially unable or unable to perform an adsorption operation to purify the exhaust gas, at which point the first adsorption device 104 may be controlled to be in fluid communication with the heating device 105 for desorption, thereby returning to the operating state. When the second adsorption device 201 is in a saturated state or an approximately saturated state, the second adsorption device 201 is substantially unable or unable to perform an adsorption operation to purify the exhaust gas, at which point the second adsorption device 201 may be controlled to be in fluid communication with the heating device 105 for desorption, thereby returning to the operating state.

[0062] As shown in Fig. 2, the filtration device 103 is connected to the reflow furnace chamber 110 and receives the exhaust gas from the reflow furnace chamber 110 for cooling, filtering, and purifying the exhaust gas and outputting the primary purified gas. When the first adsorption device 104 is in fluid communication with the filtration device 103 and the second adsorption device 201 is in fluid communication with the heating device 105, the first adsorption device 104 performs an adsorption operation and the second adsorption device 201 performs a desorption operation. At this point, the first adsorption device 104 receives the primary purified gas from the filtration device 103, performs an adsorption operation on the primary purified gas for purification, outputs the secondary purified gas, and transports the secondary purified gas to the reflow furnace chamber 110. The heating device 105 heats the air entering therein and outputs the heated air to the second adsorption device 201 ; the heated air desorbs the second adsorption device 201 in a saturated state or approximately saturated state such that the second adsorption device 201 in a saturated state or approximately saturated state returns to the operating state. The heated air entering the second adsorption device 201 from the heating device 105 heats contaminants in the exhaust gas adsorbed in the second adsorption device 201 to discharge these contaminants out of the second adsorption device 201 , thereby causing the second adsorption device 201 to desorb.

[0063] When the first adsorption device 104 is in fluid communication with the heating device 105 and the second adsorption device 201 is in fluid communication with the filtration device 103, the first adsorption device 104 performs a desorption operation and the second adsorption device 201 performs an adsorption operation. At this point, the second adsorption device 201 receives the primary purified gas from the filtration device 103, performs an adsorption operation on the primary purified gas for purification, outputs the secondary purified gas, and transports the secondary purified gas to the reflow furnace chamber 110. The heating device 105 heats the air entering therein and outputs the heated air to the first adsorption device 104; the heated air desorbs the first adsorption device 104 in a saturated state or an approximately saturated state such that the first adsorption device 104 in a saturated state or an approximately saturated state returns to the operating state. The heated air entering the first adsorption device 104 from the heating device 105 heats the exhaust gas adsorbed in the first adsorption device 104 to discharge the exhaust gas out of the first adsorption device 104, thereby causing the first adsorption device 104 to desorb.

[0064] When the first adsorption device 104 in the working state and the second adsorption device 201 are initially used, only the first adsorption device 104 may be subjected to adsorption operations while the second adsorption device 201 is not operating, and when the first adsorption device 104 has been subjected to adsorption operations for a period of time to a saturated state or an approximately saturated state, the second adsorption device 201 may be used for adsorption operations. At this point, the first adsorption device 104 reaching the saturated state or the approximately saturated state may be controlled to connect with the heating device 105 for desorption. The above described operations of the first adsorption device 104 and the second adsorption device 201 can be performed and vice versa.

[0065] Specifically, as shown in Fig. 2, the reflow furnace chamber 110 includes a heating area 101 and a cooling area 102, and the transfer device first transfers the PCB to the heating area 101 for heating and welding, and then transfers the PCB to the cooling area 102 for cooling. The heating area 101 comprises a first gas inlet 1011 , a second gas inlet 1013, and an exhaust gas outlet 1012, and the cooling area 102 comprises a first gas inlet 1021 and a second gas inlet 1022. The filtration device 103 comprises an exhaust gas inlet 1031 and a gas outlet 1032; the heating device 105 comprises an air inlet 1051 and an air outlet 1052; the first adsorption device 104 comprises a gas inlet 1041 , a purified gas outlet 1042, an air inlet 1043, and an exhaust gas outlet 1044; the second adsorption device 201 comprises a gas inlet 2011 , a purified gas outlet 2012, an air inlet 2013, and an exhaust outlet 2014. The first gas inlet 1011 of the heating area 101 and the first gas inlet 1021 of the cooling area 102 are used for receiving nitrogen (N2) to provide a low oxygen environment for PCB welding. The exhaust gas outlet 1012 of the heating area 101 is in fluid communication with the exhaust gas inlet 1031 of the filtration device 103. The gas outlet 1032 of the filtration device 103 is controllably in alternate fluid communication with the gas inlet 1041 of the first adsorption device 104 and the gas inlet 2011 of the second adsorption device 201 through the first valve assembly. The purified gas outlet 1042 of the first adsorption device 104 is in fluid communication with the second gas inlet 1013 of the heating area 101 and/or the second gas inlet 1022 of the cooling area 102. The purified gas outlet 2012 of the second adsorption device 201 is in fluid communication with the second gas inlet 1013 of the heating area 101 and/or the second gas inlet 1022 of the cooling area 102. The air inlet 1051 of the heating device 105 is used for receiving air or compressed air, and the air outlet 1052 of the heating device 105 is controllably in alternate fluid communication with the air inlet 1043 of the first adsorption device 104 and the air inlet 2013 of the second adsorption device 201 through the second valve assembly. The exhaust gas outlet 1044 of the first adsorption device 104 is used for discharging the exhaust gas generated by the first adsorption device 104 during desorption. The exhaust gas outlet 2014 of the second adsorption device 201 is used for discharging the exhaust gas generated by the second adsorption device 201 during desorption.

[0066] The first valve assembly is used for controlling fluid communication of the filtration device 103 with one of the first adsorption device 104 and the second adsorption device 201 . The second valve assembly is used for controlling fluid communication of the heating device 105 with one of the first adsorption device 104 and the second adsorption device 201 . When the first valve assembly controls the filtration device 103 to be in fluid communication with one of the first adsorption device 104 and the second adsorption device 201 , the second valve assembly controls the heating device 105 to be in fluid communication with the other of the first adsorption device 104 and the second adsorption device 201 . The first valve assembly includes a first valve 1061 and a third valve 2073, and the second valve assembly includes a second valve 1062 and a fourth valve 2074. The first valve 1061 is used to control fluid communication or disconnection of the filtration device 103 and the first adsorption device 104, the third valve 2073 is used to control fluid communication or disconnection of the filtration device 103 and the second adsorption device 201 , the second valve 1062 is used to control fluid communication or disconnection of the heating device 105 and the first adsorption device 104; the fourth valve 2074 is used for controlling fluid communication or disconnection of the heating device 105 with the second adsorption device 201 . The first and second valve assemblies comprise other forms of valve structures.

[0067] During the operation, the filtration device 103 receives the exhaust gas from the heating area 101 through the exhaust gas inlet 1031 , cools, filters, and purifies the received exhaust gas, and outputs the primary purified gas through the gas outlet 1032. The filtration device 103 cools and filters the exhaust gas to remove some contaminants from the exhaust gas, thereby outputting the primary purified gas.

[0068] When the first adsorption device 104 performs an adsorption operation, the second adsorption device 201 performs a desorption operation. At this point, the first valve assembly controls the filtration device 103 to fluidly communicate with the first adsorption device 104 and fluidly disconnect with the second adsorption device 201 , and the second valve assembly controls the heating device 105 to fluidly communicate with the second adsorption device 201 and fluidly disconnect with the first adsorption device 104. As shown in Fig. 2, when the first valve 1061 in the first valve assembly controls fluid communication between the filtration device 103 and the first adsorption device 104, the third valve 2073 in the first valve assembly controls fluid disconnection between the filtration device 103 and the second adsorption device 201 ; the second valve 1062 in the second valve assembly controls fluid disconnection between the heating device 105 and the first adsorption device 104, and the fourth valve 2074 in the second valve assembly controls fluid communication between the heating device 105 and the second adsorption device 201.

[0069] As previously described, when the first adsorption device 104 performs an adsorption operation, the second adsorption device 201 performs a desorption operation. At this point, the first adsorption device 104 receives the primary purified gas from the filtration device 103 through the gas inlet 1041 , performs an adsorption operation on the primary purified gas to purify it, and transports the secondary purified gas to the heating area 101 and/or the cooling area 102 through the purified gas outlet 1042. The heating area 101 receives the secondary purified gas from the first adsorption device 104 through the second gas inlet 1013 to provide a required working environment for welding. The cooling area 102 receives the secondary purified gas from the first adsorption device 104 through the second gas inlet 1022 to provide a required working environment for welding. Since the exhaust gas pumped out of the heating area 101 includes a portion of the nitrogen (N2) received by the heating area 101 from the first gas inlet 1011 , and the filtration device 103 and the first adsorption device 104 do not remove nitrogen (N2) during purification, the secondary purified gas purified and outputted by the filtration device 103 and the first adsorption device 104 includes nitrogen (N2), which may be delivered to the heating area 101 and/or the cooling area 102 for recycling.

[0070] As previously described, when the first adsorption device 104 performs an adsorption operation, the second adsorption device 201 performs a desorption operation. At this point, the heating device 105 receives air through the air inlet 1051 , heats the received air, and transports the heated air through the air outlet 1052 to the second adsorption device 201. The second adsorption device 201 in the saturated state or approximately saturated state receives heated air from the heating device 105 through the air inlet 2013, uses the heated air to desorb the contaminants in the adsorbed exhaust gas in the second adsorption device 201 to restore the second adsorption device 201 in the saturated state or approximately saturated state to the operating state and output the exhaust gas through the exhaust gas outlet 2014. In other examples, the heating device 105 may receive compressed air through the air inlet 1051 , such as from a compressor, and heat the received compressed air to output the heated air.

[0071] When the first adsorption device 104 performs a desorption operation, the second adsorption device 201 performs an adsorption operation. At this point, the first valve assembly controls that the filtration device 103 to fluidly communicate with the second adsorption device 201 and fluidly disconnect with the first adsorption device 104, and the second valve assembly controls the heating device 105 to fluidly communicate with the first adsorption device 104 and fluidly disconnect with the second adsorption device 201 . As shown in Fig. 2, when the first valve 1061 in the first valve assembly controls the fluid disconnection of the filtration device 103 with the first adsorption device 104, the third valve 2073 in the first valve assembly controls the fluid communication of the filtration device 103 with the second adsorption device 201 , the second valve 1062 in the second valve assembly controls the fluid communication of the heating device 105 with the first adsorption device 104, and the fourth valve 2074 in the second valve assembly controls the fluid disconnection of the heating device 105 with the second adsorption device 201 .

[0072] As previously described, when the first adsorption device 104 performs a desorption operation, the second adsorption device 201 performs an absorption operation. At this point, the second adsorption device 201 receives the primary purified gas from the filtration device 103 through the gas inlet 2011 , performs an adsorption operation on the primary purified gas to purify it, and transports the secondary purified gas to the heating area 101 and/or the cooling area 102 through the purified gas outlet 2012. The heating area 101 receives the secondary purified gas from the second adsorption device 201 through the second gas inlet 1013 to provide a required working environment for welding. The cooling area 102 receives the secondary purified gas from the second adsorption device 201 through the second gas inlet 1022 to provide a required working environment for welding. Since the exhaust gas pumped out of the heating area 101 includes a portion of the nitrogen (N2) received by the heating area 101 from the first gas inlet 1011 , and the filtration device 103 and the second adsorption device 201 do not remove nitrogen (N2) during purification, the secondary purified gas purified and outputted the filtration device 103 and the second adsorption device 201 includes nitrogen (N2), which may be delivered to the heating area 101 and/or the cooling area 102 for recycling.

[0073] As previously described, when the first adsorption device 104 performs a desorption operation, the second adsorption device 201 performs an absorption operation. At this point, the heating device 105 receives air through the air inlet 1051 , heats the received air, and transports the heated air to the first adsorption device 104 through the air outlet 1052. The first adsorption device 104 in the saturated state or approximately saturated state receives heated air from the heating device 105 through the air inlet 1043, uses the heated air to desorb the contaminants in the adsorbed exhaust gas in the first adsorption device 104 to return the first adsorption device 104 in the saturated state or approximately saturated state to the operating state and output exhaust gas through the exhaust gas outlet 1044. In other examples, the heating device 105 may receive compressed air through the air inlet 1051 , such as from a compressor, and heat the received compressed air to output the heated air.

[0074] Figs. 3A-G show a general schematic diagram of one example of the filtration device 103 in the exhaust gas purification systems 100 and 200 presented in Fig. 1 and Fig. 2, wherein Fig. 3A is a schematic diagram of the filtration device 103; Fig. 3B is a top view of Fig. 3A; Fig. 3C is a schematic diagram of the filtration device 103 removing the top 304, the left 305, the right 306, and the rear 308 of the housing (retaining the front 307 and the bottom of the housing); Fig. 3D is a left view of Fig. 3C; Fig. 3E is a right view of Fig. 3C; Fig. 3F is a top view of Fig. 3C; Fig. 3G is a bottom view of the bottom of the filtration device 103 removing the housing in Fig. 3A.

[0075] The filtration device 103 is used for cooling, filtering, and purifying exhaust gas from the reflow furnace chamber 110 and outputting the primary purified gas. The filtration device 103 comprises a cooling unit 111 and a filtering unit 112. As shown in Fig. 3C, the cooling unit 111 includes a first stage cooling component 301 and a second stage cooling component 302, and the filtering unit 112 includes a filter component 303. The first stage cooling component 301 and the second stage cooling component 302 are used for cooling and purifying the exhaust gas and output the cooled and purified exhaust gas. The first stage cooling component 301 and the second stage cooling component 302 cool the exhaust gas so that some of the contaminants in the exhaust gas are condensed into liquids and/or solids, thereby removing that portion of the contaminants from the exhaust gas, and thus the exhaust gas is purified. The first stage cooling component 301 and the second stage cooling component 302 also discharge the condensed liquids and/or solids. The filter component 303 is used for filtering the cooled purified exhaust gas from the cooling unit 111 to purify the cooled and purified exhaust gas and output the primary purified gas. The filter component 303 filters the cooled and purifies exhaust gas from the cooling unit 111 to filter out liquids and/or solids in the cooled and purified exhaust gas, thereby further purifying the cooled and purified exhaust gas and outputting the primary purified gas.

[0076] As shown in Figs. 3A-B, the filtration device 103 includes a housing that is generally box-shaped with a cavity inside, including a top 304, a bottom, a left 305, a right 306, a front 307, and a rear 308. The filtration device 103 also includes an exhaust gas inlet 1031 and a gas outlet 1032 disposed on the housing. The exhaust gas inlet 1031 is connected by the connecting pipe 330 with the reflow furnace chamber 110, such as heating area 101 of the reflow furnace chamber 110. The gas outlet 1032 is provided with a connection pipe 309, and the connection pipe 309 can be provided with a valve for controlling the fluid communication or disconnection of the filtration device 103 with the adsorption devices 104 and 201. The gas outlet 1032 is connected with the adsorption devices 104 and 201 by the connection pipe 309. Exhaust gas discharged from the reflow furnace chamber 110 can enter the filtration device 103 from the exhaust gas inlet 1031 , cool, filter, and purify the exhaust gas through the filtration device 103 into the primary purified gas before being discharged from the gas outlet 1032 to the adsorption devices 104 and 201 .

[0077] As shown in Figs. 3A-C, the front 307 of the housing includes a first front plate 310 and a second front plate 311 . The first front plate 310 is used for sealing the first cooling cavity 312 inside the housing from the front direction and the second front plate 311 is used for sealing the second cooling cavity 313 inside the housing from the front direction. The first front plate 310 is provided with an inlet 3101 and an outlet 3102, wherein a cooling medium (e.g., air) enters the first cooling cavity 312 through the inlet 3101 and exits the first cooling cavity 312 through the outlet 3102. The second front plate 311 is also provided with an inlet 3111 and an outlet 3112, where a cooling medium (e.g., air) enters the second cooling cavity 313 through the inlet 3111 and exits the second cooling cavity 313 through the outlet 3112. The cooling medium flows through the first stage cooling component 301 and the second stage cooling component 302 in the first and second cooling cavities 312 and 313 for heat exchange with the exhaust gas in the first and second cooling cavities 312 and 313 to cool the exhaust gas, as detailed below.

[0078] As shown in Figs. 3A-E, the filtration device 103 further includes a cooling collection duct 318 and a filtering collection duct 319 mounted at the bottom of the housing. The cooling collection duct 318 is connected to the cooling collection cavity 316 (see Fig. 3D) inside the housing, and the filtering collection duct 319 is connected to the filtering collection cavity 317 (see Fig. 3E) inside the housing.

[0079] The cooling collection cavity 316 is disposed below the first and second cooling cavities 312 and 313 and in fluid communication with both of the first and second cooling cavities 312 and 313 for collecting contaminants, such as liquid and/or solid contaminants, discharged from the first and second cooling cavities 312 and 313. The filtering collection cavity 317 is disposed below the filtration cavity 314 and the exhaust cavity 315 and is in fluid communication with both of the filtration cavity 314 and the exhaust cavity 315 for collecting contaminants, such as liquid and/or solid contaminants, discharged from the filtration cavity 314 and the exhaust cavity 315. The cooling collection duct 318 and the filtering collection duct 319 can be connected with a collection vessel (not shown) to cause the collection vessel to collect contaminants discharged from the first cooling cavity 312, the second cooling cavity 313, the filtering cavity 314, and the exhaust cavity 315. The bottom of the housing constitutes the bottom of the cooling collection cavity 316. The bottom of the cooling collection cavity 316 comprises three parts, namely, a first plate 320, a sloped plate 321 , and a second plate 322 from the rear to the front when seeing from the front of the filtration device 103, the second plate 322 being lower than the first plate 320, wherein the rear end of the sloped plate 321 is connected with the first plate 320, the front end of the sloped plate 321 is connected with the second plate 322, and the second sloped plate 321 is gradually sloped downward from its rear end to the front end (see Fig. 3D and Fig. 3E). A cooling collection duct 318 and a filtering collection duct 319 are provided on the second plate 322. By providing the sloped plate 321 , it is easier for the contaminants condensed into liquids and/or solids to discharge from the cooling collection duct 318 and the filtering collection duct 319. The filtering collection cavity 317 has a similar structure to the cooling collection cavity 316.

[0080] As shown in Figs. 3A-G, the bottom of the filtration device 103 may be mounted with movable stands 3310 and 3311 to facilitate moving the filtration device 103 to the desired position. In other examples, the filtration device 103 may not include moving stands, but be mounted to the desired position by, for example, a fastening assembly.

[0081] Figs. 3C-G illustrate the internal structure and components of the filtration device 103. The interior of the housing includes a plurality of cavities divided into two layers, the upper layer including a first cooling cavity 312, a second cooling cavity 313, a filtration cavity 314, and an exhaust cavity 315, the lower layer including a cooling collection cavity 316 and a filtering collection cavity 317. Looking from the front of the filtration device 103, from left to right, the first cooling cavity 312 is provided in a first column, the second cooling cavity 313 in a second column, the filtration cavity 314 and the exhaust cavity 315 in a third column, wherein the filtration cavity 314 is provided in the rear of the third column, and the exhaust cavity 315 is provided in the front of the third column. The first cooling cavity 312, the second cooling cavity 313, the filtration cavity 314, and the exhaust cavity 315 are in sequential fluid communication; the first cooling cavity 312 is in fluid communication with the exhaust gas inlet 1031 , and the exhaust cavity 315 is in fluid communication with the gas outlet 1032. Exhaust gas from the reflow furnace chamber enters the filtration device 103 through the exhaust gas inlet 1031 , passes through the first cooling cavity 312, the second cooling cavity 313, the filtration cavity 314, and the exhaust cavity 315 sequentially, and is discharged to the adsorption devices 104 and 201 through the gas outlet 1032.

[0082] The first stage cooling component 301 is provided in the first cooling cavity 312, and the second stage cooling component 302 is provided in the second cooling cavity 313; the filter component 303 is provided in the filtration cavity 314, and the fan 323 is provided in the exhaust cavity 315. The first stage cooling component 301 and the second stage cooling component 302 cool the exhaust gas so that some of the contaminants in the exhaust gas condense into liquids and/or solids, which can be discharged from the first stage cooling component 301 and the second stage cooling component 302 to the cooling collection cavity 316, and the remaining uncondensed exhaust gas is discharged to the filtration cavity 314. In this way, the portion of the contaminants in the exhaust gas are removed; that is to say, the exhaust gas is cooled and purified. The filter component 303 filters the cooled and purified exhaust gas from the second stage cooling component 302 to filter out liquid and/or solid contaminants (i.e., another portion of the contaminants) in the cooled and purified exhaust gas, thereby further purifying the exhaust gas and outputting the primary purified gas. The fan 323 in the exhaust cavity 315 helps to flow exhaust gas through individual cavities in the filtration device 103. The fan 323 is connected with a motor 324 of the top 304 of the housing, and the motor 324 drives the fan 323 to operate. When the fan 323 is operating, the exhaust gas enters the first and second cooling cavities 312 and 313 sequentially through the exhaust gas inlet 1031 , is cooled by the first and second stage cooling components 301 and 302 to remove some of the contaminants from the exhaust gas, and then enters the filtration cavity 314 to be filtered by the filter component 303 and remove another portion of the contaminants from the exhaust gas, and then enter the exhaust cavity 315 to be discharged from the gas outlet 1032. Exhaust gas discharged from the filter component 303 enters the exhaust gas cavity 315 to contact with the blades of the fan 323 such that a small portion of liquid/or solid contaminants mixed in the exhaust gas are adhered to the blades of the fan 323 and may be discharged to the filtering collection cavity 317.

[0083] The first stage cooling component 301 includes a first heat exchanger 3011 , an upper plate 3012, and a lower plate 3013, wherein the upper plate 3012 is mounted to the upper surface of the first heat exchanger 3011 , and the lower plate 3013 is mounted to the lower surface of the first heat exchanger 3011 . As shown in Figs. 3F-G, the upper plate 3012 is provided with an inlet 3014 near the front 307 of the housing, and the inlet 3014 is in fluid communication with the exhaust gas inlet 1031 and the connecting pipe 330 of the first cooling cavity 312, so that exhaust gas from the reflow furnace chamber 110 can pass through the connecting pipe 330 and the exhaust gas inlet 1031 sequentially into the first heat exchanger 3011 . The lower plate 3013 is provided with an outlet 3015 near the rear 308 of the housing, and the outlet 3015 is in fluid communication with the cooling collection cavity 316, so that the exhaust gas cooled and purified through the first heat exchanger 3011 can be discharged from the outlet 3015 to the cooling collection cavity 316. The cooling collection cavity 316 is in fluid communication with the second cooling cavity 313, so the exhaust gas discharged from the first cooling cavity 312 may enter the second cooling cavity 313.

[0084] The first heat exchanger 3011 comprises a plurality of cooling plates 3016, and each cooling plate 3016 may contain the cooling medium (e.g., air) inside, with exhaust gas flowing outside the cooling plate 3016. The cooling medium inside the cooling plate 3016 is heat exchanged with the exhaust gas outside the cooling plate 3016 through the outer peripheral side walls of the cooling plate 3016, reducing the temperature of the exhaust gas. The interior of these cooling plates 3016 is in fluid communication to form a cooling medium channel through which cooling medium (e.g., air) may flow. The inlet and outlet of the cooling medium channel are in fluid communication with the inlet 3101 and the outlet 3102 of the first front plate 310, respectively, so the cooling medium can enter the inlet of the cooling medium channel of the first heat exchanger 3011 from the inlet 3101 of the first front plate 310, flow through the cooling medium channel of the first heat exchanger 3011 and out of the outlet of the cooling medium channel, and then out of the outlet 3102 of the first front plate 310. The plurality of cooling plates 3016 of the first heat exchanger 3011 are vertically disposed side-by-side and spaced apart, with the upper plate 3012 and the lower plate 3013 disposed at the upper and lower sides of the plurality of cooling plates 3016 side-by-side, respectively. Exhaust gas enters the space between the individual cooling plates 3016 through the inlet 3014 of the upper plate 3012, flows from near the front 307 of the housing towards the rear 308 of the housing, and is discharged through the outlet 3015 of the lower plate 3013 to the cooling collection cavity 316 below the first cooling cavity 312 near the rear 308 of the housing. Since the cooling medium is heat exchanged with the exhaust gas to reduce the temperature of the exhaust gas, when the exhaust gas in the space between the cooling plates 3016 flows from near the front 307 of the housing to the rear 308 of the housing, a portion of the exhaust gas (e.g., contaminants) condenses into liquids and/or solids due to the decreased temperature, and such liquids and/or solids are discharged from the outlet 3015 of the lower plate 3013 to the cooling collection cavity 316 below the first cooling cavity 312 after being accumulated within the first heat exchanger 3011 .

[0085] The second stage cooling component 302 includes a second heat exchanger 3021 , an upper plate 3022, and a lower plate 3023, with the upper plate 3022 mounted to an upper surface of the second heat exchanger 3021 and the lower plate 3023 mounted to a lower surface of the second heat exchanger 3021 . As shown in Figs. 3F-G, the lower plate 3023 is provided with an inlet 3024 proximate to the front 307 of the housing, and the inlet 3024 is in fluid communication with the cooling collection cavity 316. As previously described, the outlet 3015 of the lower plate of the first stage cooling component 301 is in fluid communication with the cooling collection cavity 316, so the outlet 3015 of the lower plate of the first stage cooling component 301 and the inlet 3024 of the lower plate of the second stage cooling component 302 are in fluid communication via the cooling collection cavity 316. The upper plate 3022 of the second stage cooling component 302 is provided with an outlet 3025 proximate to the rear 308 of the housing, and the outlet 3025 is in fluid communication with the inlet 3140 of the filtration cavity 314, so the exhaust gas can be discharged from the second stage cooling component 302 to the filtration cavity 314. The inlet 3140 is disposed proximate to the outlet 3025.

[0086] As with the first heat exchanger 3011 , the second heat exchanger 3021 also includes a plurality of cooling plates 3026, and each cooling plate 3026 may contain a cooling medium (e.g., air) inside, with exhaust gas flowing outside the cooling plate 3026. The plurality of cooling plates 3026 are disposed side-by-side and spaced apart, with the upper plate 3022 and the lower plate 3023 disposed at upper and lower sides of the plurality of cooling plates 3026 side-by-side, respectively. In the second stage cooling component 302, the cooling medium enters the inlet of the cooling medium channel of the second heat exchanger 3021 from the inlet 3111 of the second front plate 311 , flows through the cooling medium channel of the second heat exchanger 3021 and out of the outlet of the cooling medium channel, and then exits the outlet 3112 of the second front plate 311 . Meanwhile, the exhaust gas enters the space between the individual cooling plates through the inlet 3024 of the lower plate 3023, flows from near the front 307 of the housing towards the rear 308 of the housing, and is discharged to the filtration cavity 314 through the outlet 3025 of the upper plate 3022 near the rear 308 of the housing. Since the cooling medium is heat exchanged with the exhaust gas to reduce the temperature of the exhaust gas, when the exhaust gas in the space between the cooling plates 3026 flows from near the front 307 of the housing to the rear 308 of the housing, a portion of the exhaust gas (e.g., contaminants) condenses into liquids and/or solids due to the decreased temperature, and such liquids and/or solids are discharged from the inlet 3024 of the lower plate 3023 to the cooling collection cavity 316 below the first cooling cavity 312 after being accumulated within the first heat exchanger 3021 .

[0087] The first heat exchanger 3011 and the second heat exchanger 3021 may operate in serial or parallel. When the first heat exchanger 3011 and the second heat exchanger 3021 are operated in serial, the outlet 3102 of the first front plate 310 is in fluid communication with the inlet 3111 of the second front plate 311 , so that the cooling medium (e.g., air) discharged from the first heat exchanger 3011 can enter the second heat exchanger 3021. Specifically, the cooling medium (e.g., air) enters the first heat exchanger 3011 through the inlet 3101 of the first front plate 310, passes through the first heat exchanger 3011 , enters the second heat exchanger 3021 through the outlet 3102 of the first front plate 310 and the inlet 3111 of the second front plate 311 , and passes through the second heat exchanger 3021 and exits through the outlet 3112 of the second front plate 311 . When the first heat exchanger 3011 and the second heat exchanger 3021 are operated in parallel, the first heat exchanger 3011 and the second heat exchanger 3021 work independently, and the outlet 3102 of the first front plate 310 is not in fluid communication with the inlet 3111 of the second front plate 311 . At this point, the cooling medium (e.g., air) enters the first heat exchanger 3011 via the inlet 3101 of the first front plate 310 and is discharged via the outlet 3102 of the first front plate 310 after flowing through the first heat exchanger 3011 . In parallel, another cooling medium (e.g., air) enters the second heat exchanger 3021 via the inlet 3111 of the second front plate 311 and is discharged via the outlet 3112 of the second front plate 311 after flowing through the second heat exchanger 3021 .

[0088] After exhausting the contaminant-containing exhaust gas (at a temperature of approximately 170°C) in the reflow furnace chamber 110 from the heating area 101 of the reflow furnace, it is first cooled to a first temperature (e.g., 60-70°C) through the first stage cooling component 301 and then further cooled to a second temperature (e.g., 40-50°C) through the second stage cooling component 302 so that organics including rosin, alcohols, acids, or esters, or ether organics (e.g., 4- terpenenol, alpha-pinol, tripropylene glycol methyl ether, diethylene glycol monohexane, 2-methyl-2,4-pentanediol, N-methylpyrrolidone, etc.) are condensed into liquids and/or solids. This condensed liquids and/or solids can be discharged to the cooling collection cavity 316, and the remaining exhaust gas is discharged to the filtration cavity 314, so that the exhaust gas is cooled and purified.

[0089] The filter component 303 is provided in the filtration cavity 314. The filter component 303 filters the cooled and purified exhaust gas from the second stage cooling component 302 to remove liquid and/or solid contaminants (i.e. , another portion of the contaminants) in the cooled and purified exhaust gas, thereby further purifying the exhaust gas and outputting the primary purified gas. As previously described, the first stage cooling component 301 and the second stage cooling component 302 cool the exhaust gas so that some of the contaminants in the exhaust gas are condensed into liquids and/or solids, thereby removing this portion of the contaminants from the exhaust gas and outputting the cooled and purified exhaust gas. Although a portion of the exhaust gas is condensed and discharged to the cooling collection cavity 316, there may be a portion of the liquids and/or solids suspended in the gas and discharged to the filtration cavity 314 as the gas flows.

The filter component 303 is used for the promoting the passage of gas in the exhaust gas and blocking the passage of liquids and solids in the exhaust gas, thereby filtering out liquids and solids in the exhaust gas. As shown in Figs. 3C-G, the filter component 303 is mounted transversely in the filtration cavity 314, and due to the blowing of the fan 323 in the exhaust cavity 315, the exhaust gas can flow from top to bottom through the filter component 303 after entering the filtration cavity 314 and out of the outlet 3031 below the filter component 303 to the filtering collection cavity 317 below the filtration cavity 314. The liquids and solids in the exhaust gas are blocked above the filter component 303, and the gas in the exhaust gas flows out through the outlet 3031 to the filtering collection cavity 317. Although the filter component 303 promotes the passage of the gas in the exhaust gas and blocks the passage of liquids and solids in the exhaust gas, a small portion of the liquids and/or solids may still be mixed in the gas passing through the filter component 303. The gas discharged from the filtration cavity 314 may contact with the bottom of the filtering collection cavity 317 so that liquids and/or solids suspended in the gas are adhered to the bottom of the filtering collection cavity 317, thereby being collected in the filtering collection cavity 317. The filter component 303 comprises a filter cotton. In other examples, the filter component 303 includes other structures for filtering out liquids and/or solids suspended in a gas.

[0090] The exhaust cavity 315 is in fluid communication with the filtering collection cavity 317. The fan 323 in the exhaust cavity 315 draws the exhaust gas from the filtering collection cavity 317 into the exhaust cavity 315, and when the exhaust gas enters the exhaust cavity 315 to contact with the blades of the fan 323, a small portion of the liquid/or solid contaminants mixed in the exhaust gas will adhere to the blades, which may accumulate and drip to the filtering collection cavity 317 below the exhaust cavity 315. The remaining exhaust gas in the exhaust cavity 315 is discharged through the gas outlet 1032.

[0091] Fig. 4 shows a structural schematic diagram of one example of a heating device 105 in the exhaust gas purification systems 100 and 200 shown in Figs. 1 and 2. The heating device 105 is used for heating the air entering therein and outputting the heated air to the adsorption devices 104 and 201 . The heated air is used for desorbing the adsorption devices 104 and 201 in a saturated state or an approximately saturated state, so that the adsorption devices 104 and 201 in a saturated state or an approximately saturated state return to the operating state without being in a saturated state or an approximately saturated state. In the operating state, the adsorption devices 104 and 201 may reperform an adsorption operation to purify the gas.

[0092] As shown in Fig. 4, the heating device 105 comprises a housing 401 and a heating wire 402 disposed within the housing 401 . The housing 401 is provided with an air inlet 1051 and an air outlet 1052, and the air enters into the housing 401 from the air inlet 1051 and is discharged out of the housing 401 through the air outlet 1052. In one example, the air is atmospheric air, so the air may be blown into the housing 401 by a fan. In another example, the air entering the housing 401 may be compressed air outputted by the compressor. During the operation, the air enters the housing 401 through the air inlet 1051 , and the heating wire 402 heat the incoming air; the heated air then exits the housing 401 through the air outlet 1052, and is transported to the adsorption devices 104 and 201 for desorption by the adsorption devices 104 and 201. [0093] The heating wire 402 is used for heating the air entering the housing 401 . When the heating wire 402 is energized, the heating wire 402 rises in temperature and generate heat, and the heat generated by the heating wire 402 diffuses outwardly and is transferred into the air within the housing 401 , thereby heating the air within the housing 401. In other examples, the heating device 105 comprises other structures for heating the air.

[0094] Figs. 5A-D show general structural schematic diagrams of one example of the first adsorption device 104 in the exhaust gas purification systems 100 and 200 presented in Figs. 1 and 2, wherein Fig. 5A is a schematic diagram of the first adsorption device 104; Fig. 5B is a schematic diagram of the first adsorption device 104 in Fig. 5A that removes the top; Fig. 5C is a front view of Fig. 5B, and Fig. 5D is a top view of Fig. 5B. The second adsorption device 201 in Fig. 2 is identical or substantially identical to the first adsorption device 104 in terms of the structure, not otherwise shown and illustrated here.

[0095] The first adsorption device 104 is used for absorbing contaminants remaining in the exhaust gas in the filtration device 103 due to insufficiently low cooling temperature. The first adsorption device 104 may absorb flux that cannot be cooled off and removed at its set temperature by the filtration device 103, thereby avoiding the reduction of the amount of flux in the exhaust gas by further reducing the cooling temperature of the filtration device 103, and reducing the removal costs. The heating device 105 is used for desorbing the saturated first adsorption device 104 so that the first adsorption device 104 can be reused.

[0096] The first adsorption device 104 may only perform adsorption operations only, and may also alternately perform adsorption and desorption operations. When the first adsorption device 104 is performing an adsorption operation, the first adsorption device 104 is in fluid communication with the filtration device 103. The first adsorption device 104 performs an adsorption operation on the primary purified gas from the filtration device 103 to purify the primary purified gas and output and transport the secondary purified gas to the reflow furnace chamber. When the first adsorption device 104 performs an adsorption operation for a period of time to reach a saturated state or an approximately saturated state, the first adsorption device 104 cannot or is substantially no longer able to adsorb exhaust gas into the first adsorption device 104 to purify the exhaust gas. The first adsorption device 104 in the saturated state or approximately saturated state may use the heating device 105 to perform a desorption operation to return to the operating state. The first adsorption device 104 is in fluid communication with the heating device 105 when the first adsorption device 104 is in a saturated state or an approximately saturated state for desorption operations. The first adsorption device 104, in a saturated state or an approximately saturated state, receives heated air from the heating device 105, and the heated air transfers heat to contaminants in the exhaust gas adsorbed by the first adsorption device 104 during adsorption operations so that the temperature of individual molecules in the contaminants is elevated so as not to adsorb on or inside the adsorption material 509 (e.g., hole) of the first adsorption device 104 anymore, and discharges the contaminants out of the first adsorption device 104 as the heated air flows. The first adsorption device 104 may perform an desorption operation when or before the saturated state is reached, for example when the approximately saturated state is reached.

[0097] As shown in Figs. 5A-D, the first adsorption device 104 comprises a housing that is generally box-shaped with a cavity inside, including the top 500, the bottom 501 , the left 502, the right 503, the front 504, and the rear 505. The front 504 of the housing includes a gas inlet 1041 proximate to the left 502 of the housing and a purified gas outlet 1042 proximate to the right 503 of the housing. The right 503 of the housing comprises an air inlet 1043, and the left 502 of the housing comprises an exhaust gas outlet 1044.

[0098] The gas inlet 1041 is connected with a duct 506, and the duct 506 is used for connecting with the gas outlet 1032 of the filtration device 103 to receive the primary purified gas from the filtration device 103. A valve is provided in the duct 506 for controlling the gas inlet 1041 of the first adsorption device 104 to be in fluid communication or disconnection with the gas outlet 1032 of the filtration device 103. The purified gas outlet 1042 is connected with a duct 507, and the duct 507 is used for connecting with the second gas inlet 1013 of the heating area 101 and/or the second gas inlet 1022 of the cooling area 102 of the reflow furnace chamber to input the secondary purified gas purified by the first adsorption device 104 to the heating area 101 and/or the cooling area 102. A valve is provided in the duct 507 to control the purified gas outlet 1042 of the first adsorption device 104 to be in fluid communication or disconnection with the second gas inlet 1013 of the heating area 101 , thereby controlling whether the first adsorption device 104 inputs the secondary purified gas into the heating area 101. The valve may also be used for controlling the purified gas outlet 1042 of the first adsorption device 104 to be in fluid communication or disconnection with the second gas inlet 1022 of the cooling area

102.

[0099] The air inlet 1043 is used for connecting with the air outlet 1052 of the heating device 105; for example, it can be connected with the air outlet 1052 of the heating device 105 through a duct to receive heated air from the heating device 105. A valve is provided in the duct for controlling the air inlet 1043 of the first adsorption device 104 to be in fluid communication or disconnection with the air outlet 1052 of the heating device 105. The exhaust gas outlet 1044 is used for discharging the exhaust gas generated after the first adsorption device 104 performs an adsorption operation. The exhaust gas outlet 1044 may be connected with a duct in which a valve is provided to control whether the exhaust gas is discharged from first adsorption device 104.

[0100] At least one of the top 500, the bottom 501 , the left 502, the right 503, the front 504, and the rear 505 of the housing includes an insulation layer 508 for insulation. The temperature within the housing is higher because of the higher desorption temperature, for example about 250°C, when the first adsorption device 104 is performing a desorption operation. The insulation layer 508 is provided such that the temperature of the outer surface of the housing is below a predetermined temperature.

[0101] The first adsorption device 104 further comprises an adsorption material 509 disposed within the housing. The adsorption material 509 is used for adsorbing the primary purified gas from the filtration device 103 to the surface and/or interior of the adsorption material 509 (e.g., a hole) for adsorption operations. When a desorption operation is performed, the heated air enters the adsorption material 509 and the heat is transferred to the adsorbed contaminants in the adsorption material 509 such that the temperature of individual molecules in the contaminants is elevated so as not to adsorb on or inside the adsorption material 509 (e.g., hole), and these molecules expel the adsorption material 509 as the heated air flows. [0102] The adsorption material 509 includes a honeycomb zeolite molecular sieve. There are many holes of a certain size in the molecular sieve crystal, as well as many holes with the same diameter between the holes. This sieve can be used for removing contaminants from the exhaust gas by adsorbing molecules smaller than their pore size into the hole and repelling molecules larger than their pore size out of their hole. When a portion of the molecules of a substance are adsorbed to the interior of the hole of the molecular sieve, some other molecules are adsorbed on and/or inside the hole of the molecular sieve due to the intermolecular forces. The adsorption material 509 also includes other appropriate materials for adsorption.

[0103] Figs. 5B and 5D show four honeycomb zeolite molecular sieves arranged in rows. The honeycomb zeolite molecular sieves are approximately cubics with honeycomb 3.2 mm hex holes. This honeycomb zeolite molecular sieves can be used for removing VOC gas from the exhaust gas. In other examples, the honeycomb zeolite molecular sieves include other appropriate quantities, shapes, and/or arrangements. The honeycomb zeolite molecular sieves are separated by a window-shaped partition plate 510 and are prevented from moving in the transverse direction, and the bottom 501 of the housing is also fitted with a barrier 511 for blocking the honeycomb zeolite molecular sieves from moving in the longitudinal direction. The partition plate 510 obstructs the edges of the honeycomb zeolite molecular sieves, and exposes other portions of the honeycomb zeolite molecular sieves. The setting of the partition plate 510 basically does not affect the adsorption and desorption operations of the honeycomb zeolite molecular sieves. In other examples, the first adsorption device 104 includes other structures for immobilizing honeycomb zeolite molecular sieves.

[0104] When the first adsorption device 104 is performing an adsorption operation, the valve controls the first adsorption device 104 to be in fluid communication with the filtration device 103, at which point the gas inlet 1041 of the first adsorption device 104 is in fluid communication with the gas outlet 1032 of the filtration device 103 via the duct 506. The primary purified gas purified by the filtration device 103 is discharged from the gas outlet 1032 of the filtration device 103, and then enters the first adsorption device 104 sequentially via the duct 506 and the gas inlet 1041 . In the first adsorption device 104, the primary purified gas flows sequentially from left to right (seeing from the front of the first adsorption device 104) through four honeycomb zeolite molecular sieves, and the honeycomb zeolite molecular sieves adsorb contaminants from the primary purified gas to the surface and/or interior of its hole, thus removing contaminants from the primary purified gas and outputting secondary purified gas. When outputting the secondary purified gas, the valve controls the purified gas outlet 1042 of the first adsorption device 104 to be in fluid communication with the second gas inlet 1013 of the heating area 101 , so that the first adsorption device 104 inputs the secondary purified gas to the heating area 101 through the purified gas outlet 1042. The valve may also control the purified gas outlet 1042 of the first adsorption device 104 to be in fluid communication with the second gas inlet 1022 of the cooling area 102, so that the first adsorption device 104 inputs the secondary purified gas to the cooling area 102 through the purified gas outlet 1042.

[0105] Depending on the compound composition of the contaminants (e.g., flux) to be removed, an appropriate adsorption material may be selected to adsorb the contaminants in the exhaust gas. For example, for the exhaust gas containing N- methylpiperidine with a condensation temperature below about 0°C, a zeolite molecular sieve can be used for adsorbing the exhaust gas to the adsorption device, thereby removing N-methylpiperidine from the exhaust gas.

[0106] A valve (not shown) controls the first adsorption device 104 to be in fluid communication with the heating device 105 when the first adsorption device 104 is performing a desorption operation, at which point the air inlet 1043 of the first adsorption device 104 is in fluid communication with the air outlet 1052 of the heating device 105. The heated air is discharged from the air outlet 1052 of the heating device 105, and then enters the first adsorption device 104 via the duct and the air inlet 1043 sequentially. In the first adsorption device 104, the heated air flows sequentially from right to left (seeing from the front of the first adsorption device 104) through four honeycomb zeolite molecular sieves, which transfer the heat of the heated air to the contaminants adsorbed in the honeycomb zeolite molecular sieves as the heated air passes through the honeycomb zeolite molecular sieves, so that the temperature of individual molecules in the contaminants is elevated so as not to adsorb on or inside of the hole in the honeycomb zeolite molecular sieves any more. Also, as the heated air is discharged via the exhaust gas outlet 1044, these molecules are also discharged from the honeycomb zeolite molecular sieves; that is to say, contaminants adsorbed in the honeycomb zeolite molecular sieves are discharged out of the honeycomb zeolite molecular sieves.

[0107] As previously described, the filtration device 103 cools the exhaust gas from the reflow furnace chamber to 40-50°C so that organics including rosins, alcohols, acids or esters or ethers organics in the exhaust gas are condensed into liquids and/or solids. For other flux contaminants with condensation temperatures below 40°C (e.g., N-methylpiperidine, which has a condensation temperature below 0°C), the filtration device 103 cannot condense them into liquids and/or solids. The first adsorption device 104 uses honeycomb zeolite molecular sieves as the adsorption material 509 to adsorb other flux contaminants with condensation temperatures below 40-50°C (e.g., N-methylpiperidine, which has a condensation temperature below 0°C) that have not been removed by the filtration device 103 to the surface and/or interior of its adsorption material 509 (e.g., hole) to remove this contaminants from the exhaust gas that have not been removed by the filtration device 103.

[0108] The improvement costs of the filtration device 103 by reducing its cooling temperature, e.g., to below 0°C, are too high because the air can no longer be used as a cooling medium at this time, and it is desirable to provide equipment that produces the cooling medium, which is more energy-consuming to operate. The first adsorption device 104 of the present application, however, uses an adsorption material 509 (e.g., honeycomb zeolite molecular sieve) to remove contaminants from the exhaust gas that have not been removed by the filtration device 103. The costs of using the first adsorption device 104 equipped with the adsorption material 509 are lower than the improvement costs of lowering the cooling temperature of the filtration device 103 described above to enhance the exhaust gas removal effect. Also, an air heater is used for generating the heated air for the first adsorption device 104 to perform a desorption operation for repeated adsorption operations. This air heater consumes less energy than the equipment that produces the cooling medium, thus reducing costs.

[0109] Although the present disclosure has been described in connection with examples of the embodiments outlined above, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or foreseeable now or in the near future, may be apparent to those having at least ordinary skill in the art. Therefore, examples of the present disclosure as set forth above are intended to be illustrative and not limiting. Various changes may be made without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is intended to include all known or earlier developed alternatives, modifications, variations, improvements and/or substantial equivalents. The technical effects and technical problems in this specification are exemplary and not limiting. It should be noted that the examples described in this specification may have other technical effects and may solve other technical problems.

Claims

What is claimed is:

1.An exhaust gas purification system (100, 200) for a reflow furnace, characterized in that the exhaust gas purification system (100, 200) comprises: a filtration device (103) for receiving exhaust gas from a chamber (110) of the reflow furnace, the filtration device (103) for cooling, filtering, and purifying the exhaust gas and outputting a primary purified gas, and a first adsorption device (104) in fluid communication with the filtration device (103), the first adsorption device (104) for performing adsorption operations on the primary purified gas from the filtration device (103) to purify the primary purified gas and output a secondary purified gas, and transporting the secondary purified gas to the reflow furnace chamber (110).

2. The exhaust gas purification system (100, 200) according to Claim 1 , wherein the exhaust gas purification system (100, 200) further comprises: a heating device (105), wherein the first adsorption device (104) is controllably in alternating fluid communication with the filtration device (103) and the heating device (105), wherein:

(i) when the first adsorption device (104) is in fluid communication with the filtration device (103), the first adsorption device (104) performs an adsorption operation,

(ii) when the first adsorption device (104) is in fluid communication with the heating device (105), the first adsorption device (104) performs a desorption operation.

3. The exhaust gas purification system (100, 200) according to Claim 2, wherein the heating device (105) is for heating the air entering the heating device (105) and outputting heated air to the first adsorption device (104), and the heated air desorbs the first adsorption device (104) in a saturated state or in an approximately saturated state, thereby causing the first adsorption device (104) in a saturated state or an approximately saturated state to return to an operating state.

4. The exhaust gas purification system (100, 200) according to Claim 1 , wherein the filtration device (103) comprises: a cooling unit (111) for receiving the exhaust gas from the reflow furnace chamber (110), cooling the exhaust gas to condense some of the contaminants in the exhaust gas, and outputting the cooled and purified exhaust gas, a filtering unit (112) for receiving the cooled and purified exhaust gas from the cooling unit (111 ), filtering liquids and/or solids mixed in the cooled and purified exhaust gas, and outputting the primary purified gas.

5. The exhaust gas purification system (100, 200) according to Claim 1 , wherein the cooling temperature range of the filtration device (103) for cooling the exhaust gas comprises 40°C-50°C.

6. The exhaust gas purification system (100, 200) according to Claim 1 , wherein: the reflow furnace chamber (110) comprises a heating area (101 ) and a cooling area (102), wherein the filtration device (103) receives the exhaust gas from the heating area (101) of the reflow furnace chamber (110), and the first adsorption device (104) is used fortransporting the secondary purified gas to the heating area (101) and/or the cooling area (102) of the reflow furnace chamber (110).

7. The exhaust gas purification system (100, 200) according to Claim 2, wherein the exhaust gas purification system (100, 200) further comprises: a valve assembly for controlling the first adsorption device (104) to be in alternating fluid communication with the filtration device (103) and the heating device (105), wherein the valve assembly comprises: a first valve (1061) for controlling fluid communication or disconnection of the filtration device (103) with the first adsorption device (104); and a second valve (1062) for controlling fluid communication or disconnection of the heating device (105) with the first adsorption device (104).

8. The exhaust gas purification system (100, 200) according to Claim 1 , wherein: the first adsorption device (104) comprises a first adsorption material for adsorbing contaminants in the primary purified gas from the filtration device (103) to a surface and/or interior of the first adsorption material for adsorption operations.

9. The exhaust gas purification system (100, 200) according to Claim 8, wherein: the heated air entering the first adsorption device (104) from the heating device

(105) heats the contaminants adsorbed in the first adsorption device (104) to expel the contaminants out of the first adsorption device (104) such that the first adsorption device (104) is desorbed.

10. The exhaust gas purification system (100, 200) according to any of Claims 2-9, wherein the exhaust gas purification system (200) further comprises: a second adsorption device (201) controllably in alternating fluid communication with the filtration device (103) and the heating device (105), and the second adsorption device (201) is used for performing adsorption operations on the primary purified gas from the filtration device (103) to purify the primary purified gas and output and transport the secondary purified gas to the reflow furnace chamber (110), wherein:

(i) when the first adsorption device (104) is in fluid communication with the heating device (105), the second adsorption device (201) is in fluid communication with the filtration device (103), at which point the first adsorption device (104) is performing a desorption operation and the second adsorption device (201) is performing an adsorption operation;

(ii) when the first adsorption device (104) is in fluid communication with the filtration device (103), the second adsorption device (201) is in fluid communication with the heating device (105), at which point the first adsorption device (104) is performing an adsorption operation and the second adsorption device (201 ) is performing a desorption operation.

11. The exhaust gas purification system (100, 200) according to Claim 10, wherein:

(i) when the first adsorption device (104) is in fluid communication with the heating device (105), the first adsorption device (104) is in a saturated state or an approximately saturated state;

(ii) when the second adsorption device (201) is in fluid communication with the heating device (105), the second adsorption device (201) is in a saturated state or an approximately saturated state.

12. The exhaust gas purification system (100, 200) according to Claim 10, wherein: the heating device (105) is used for heating the air entering the heating device (105) and outputting the heated air to the second adsorption device (201 ), and the heated air desorbs the second adsorption device (201) in a saturated state or an approximately saturated state such that the second adsorption device (201) in a saturated state or an approximately saturated state returns to the operating state.

13. The exhaust gas purification system (100, 200) according to Claim 10, wherein: the reflow furnace chamber (110) comprising a heating area (101) and a cooling area (102), wherein the filtration device (103) receives the exhaust gas from the heating area (101) of the reflow furnace chamber (110), and the second adsorption device (201) is used for transporting the secondary purified gas to the heating area (101) and/or the cooling area (102) of the reflow furnace chamber (110).

14. The exhaust gas purification system (100, 200) according to Claim 10, wherein, the filtration device (103) is configured to be controllably in fluid communication with one of the first adsorption device (104) and the second adsorption device (201), and the heating device (105) is configured to be controllably in fluid communication with the other of the first adsorption device (104) and the second adsorption device (201).

15. The exhaust gas purification system (100, 200) according to Claim 14, wherein the exhaust gas purification system (100, 200) further comprises: a first valve assembly (1061 , 2073) for controlling fluid communication of the filtration device (103) with one of the first adsorption device (104) and the second adsorption device (201); and a second valve assembly (1062, 2074) for controlling fluid communication of the heating device (105) with one of the first adsorption device (104) and the second adsorption device (201).

16. The exhaust gas purification system (100, 200) according to Claim 15, wherein: the first valve assembly (1061 , 2073) comprises a first valve (1061) for controlling fluid communication or disconnection of the filtration device (103) with the first adsorption device (104), and a third valve (2073) for controlling fluid communication or disconnection of the filtration device (103) with the second adsorption device (201), the second valve assembly (1062, 2074) comprises a second valve (1062) for controlling fluid communication or disconnection of the heating device (105) with the first adsorption device (104), and a fourth valve (2074) for controlling fluid communication or disconnection of the heating device (105) with the second adsorption device (201).

17. The exhaust gas purification system (100, 200) according to Claim 10, wherein:

The second adsorption device (201) comprises a second adsorption material for adsorbing contaminants in the primary purified gas from the filtration device (103) to the surface and/or interior of the second adsorption material for adsorption operations.

18. The exhaust gas purification system (100, 200) according to Claim 12, wherein: the heated air entering the second adsorption device (201) from the heating device (105) heats the contaminants adsorbed in the second adsorption device (201 ) to discharge the contaminants from the second adsorption device (201), thus causing the second adsorption device (201) to desorb.