Exhaust gas purification device

Abstract

The present application discloses an exhaust gas purification device for purifying the exhaust gas in the furnace of a reflow soldering furnace, comprising: a filter unit; a filter component, the filter component is arranged in the filter unit; a controllable gas channel, the controllable gas channel connects the interior of the filter unit with the exterior containing oxygen in a controllable manner, the controllable gas channel is configured to controllably introduce gas containing oxygen into the filter unit; a heating component, the heating component is arranged in the filter unit, wherein the heating component is configured to heat the gas in the filter unit to an oxidation temperature, at which the carbon in the attachment on the filter component can undergo a chemical change to generate gas. The exhaust gas purification device of the present application has a long maintenance cycle, which can greatly reduce maintenance costs.

Description

Technical Field

[0001] The present application relates to an exhaust gas treatment system for a reflow soldering furnace, and in particular to an exhaust gas purification device for purifying exhaust gas in a furnace of a reflow soldering furnace. Background Art

[0002] In the process of making printed circuit boards, electronic components are usually mounted on the circuit board using a process called "reflow soldering". In a typical reflow soldering process, solder paste (e.g., tin paste) is deposited on a selected area on the circuit board, and the wires of one or more electronic components are inserted into the deposited solder paste. The circuit board then passes through a reflow soldering furnace, in which the solder paste is reflowed (i.e., heated to a melting or reflow temperature) in a heating area and then cooled in a cooling area to electrically and mechanically connect the wires of the electronic components to the circuit board. The term "circuit board" used herein includes substrate assemblies of any type of electronic components, such as wafer substrates. In the reflow soldering furnace, air or a substantially inert gas (e.g., nitrogen) is usually used as a working gas, and different working gases are used for circuit boards with different process requirements. The furnace of the reflow soldering furnace is filled with working gas, and the circuit board is soldered in the working gas when it is conveyed through the furnace by a conveyor.

[0003] In the reflow oven, the solder paste includes not only solder but also flux that makes the solder wet and provides a good solder joint. 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 on a conveyor through multiple heating zones of the reflow oven. The heat in the heating zone causes the solder paste to melt, and volatile organic compounds (called "VOCs"), mainly including flux, vaporize to form steam, thereby forming "contaminants". The accumulation of these contaminants in the reflow oven can cause some problems. For example, if the contaminants reach the cooling zone, they will condense on the circuit board and contaminate the circuit board, making it necessary to perform subsequent cleaning steps. Contaminants will also condense on the surface of the cooler of the reflow oven, thereby blocking the pores. In addition, condensation may also drip on subsequent circuit boards, which may damage components on the circuit board or make it necessary to perform subsequent cleaning steps on the contaminated circuit board.

[0004] Therefore, it is necessary to discharge the waste gas containing pollutants in the furnace of the reflow soldering furnace out of the furnace to keep the working atmosphere in the furnace of the reflow soldering furnace clean, thereby preventing pollutants from entering the cooling zone of the reflow soldering furnace and causing the above-mentioned problems in the reflow soldering furnace.

[0005] Generally speaking, the waste gas containing pollutants needs to be purified by the waste gas purification device to remove the pollutants before it can be discharged into the outside atmosphere or transported back to the furnace of the reflow oven. However, these pollutants will remain in the waste gas purification device, affecting the purification efficiency of the waste gas purification device. Therefore, the waste gas purification device needs to be regularly maintained and cleaned. Summary of the invention

[0006] In order to solve at least one of the above problems, the present application provides an exhaust gas purification device, which is used to purify the exhaust gas in the furnace of a reflow oven. The exhaust gas purification device can facilitate maintenance and cleaning and extend the maintenance cycle.

[0007] In order to achieve the above-mentioned purpose, the first aspect of the present application provides an exhaust gas purification device for purifying the exhaust gas in the furnace of a reflow soldering furnace, comprising: a filter unit; a filter component, the filter component is arranged in the filter unit; a controllable gas channel, the controllable gas channel connects the interior of the filter unit with the outside containing oxygen in a controllable manner, and the controllable gas channel is configured to: controllably introduce gas containing oxygen into the filter unit; a heating component, the heating component is arranged in the filter unit, wherein the heating component is configured to: be able to heat the gas in the filter unit to an oxidation temperature, at which the carbon in the attachment on the filter component can undergo a chemical change to produce gas.

[0008] According to the above-mentioned first aspect, the exhaust gas purification device has an exhaust gas inlet and a clean gas outlet, the downstream side of the filter component is fluidly connected to the exhaust gas inlet, and the upstream side of the filter component is fluidly connected to the clean gas outlet; wherein the heating component is arranged on the downstream side of the filter component.

[0009] According to the first aspect above, the heating component is further configured to heat the gas in the filter unit to a self-cleaning temperature, at which the flux in the attachment on the filter component can undergo a physical change and become liquid or gas.

[0010] According to the above-mentioned first aspect, the exhaust gas purification device has a self-cleaning mode and a maintenance mode; in the self-cleaning mode, the controllable gas channel is closed, and the heating component heats the gas in the filter unit to the self-cleaning temperature, so that the flux in the attachment on the filter component undergoes a physical change and becomes liquid or gas, and carbon is generated in the attachment; in the maintenance mode, the controllable gas channel is opened, and the heating component heats the gas in the filter unit to the oxidation temperature, so that the carbon in the attachment on the filter component undergoes a chemical change and generates gas.

[0011] According to the above-mentioned first aspect, the exhaust gas purification device also has an exhaust gas purification mode; in the exhaust gas purification mode, the controllable gas channel is closed, the exhaust gas in the furnace of the reflow soldering furnace is filtered through the filter component, and during the filtering process, attachments including flux remain on the filter component.

[0012] According to the above first aspect, the controllable gas passage is arranged such that: an outlet of the controllable gas passage is close to the filter component.

[0013] According to the first aspect, after the carbon in the deposits on the filter member undergoes a chemical change to generate gas, the exhaust gas purification device is cleaned by a mechanical device.

[0014] According to the above first aspect, the exhaust gas purification device further includes: a control device capable of controlling the heating temperature of the heating component so that the heating component can heat the gas in the filter unit to the oxidation temperature or the self-cleaning temperature.

[0015] According to the above first aspect, the oxidation temperature is higher than the self-cleaning temperature.

[0016] According to the first aspect above, the oxidation temperature is 400-450°C.

[0017] According to the above first aspect, the self-cleaning temperature is 150-170°C.

[0018] According to the first aspect, at the oxidation temperature, a part of the organic matter in the deposits on the filter member can also undergo chemical changes to generate gas.

[0019] The concept, specific structure and technical effects of the present application will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1A A simplified structural block diagram of an exhaust gas purification device according to an embodiment of the present application;

[0021] Figure 1B To show Figure 1A A block diagram of a gas flow path when the exhaust gas purification device is in an exhaust gas purification mode;

[0022] Figure 1C To show Figure 1A A block diagram of a gas flow path when the exhaust gas purification device is in a self-cleaning mode;

[0023] Figure 1D To show Figure 1AA block diagram of a gas flow path when the exhaust gas purification device is in a maintenance mode;

[0024] Figure 2 for Figure 1A Structural diagram of the control device of the exhaust gas purification device. DETAILED DESCRIPTION

[0025] Various specific embodiments of the present application will be described below with reference to the accompanying drawings that form a part of this specification. It should be understood that although terms indicating directions, such as "front", "rear", "upper", "lower", "left", "right", "top", "bottom", "side", etc., are used in this application to describe various example structural parts and elements of the present application, these terms are used here only for the purpose of convenience of description and are determined based on the example orientations shown in the accompanying drawings. Since the embodiments disclosed in the present application can be set in different directions, these terms indicating directions are only for illustration and should not be regarded as limitations.

[0026] Those skilled in the art should be aware that the exhaust gas or gas described in this embodiment refers to a component that is mostly gaseous, and may also contain a portion of mist or particulate components.

[0027] Figure 1A 1 shows a simplified structural block diagram of an exhaust gas purification device according to an embodiment of the present application, which is used to show the connection relationship between various parts of the exhaust gas purification device 100. Figure 1A As shown, the exhaust gas purification device 100 is disposed outside the furnace chamber 118 of the reflow soldering furnace and is connected to the furnace chamber 118 of the reflow soldering furnace. When the reflow soldering furnace uses a substantially inert gas (such as nitrogen) as a working gas, the exhaust gas purification device 100 receives the exhaust gas exhausted from the furnace chamber 118 of the reflow soldering furnace and transports the purified gas back into the furnace chamber 118. When the reflow soldering furnace uses air as a working gas, the exhaust gas purification device 100 receives the exhaust gas exhausted from the furnace chamber 118 of the reflow soldering furnace, and the purified gas may be transported back into the furnace chamber 118, or may not be transported back into the furnace chamber 118, but discharged to the outside of the furnace chamber 118. Figure 1A In the process, the exhaust gas purification device 100 transports the purified gas back to the furnace 118.

[0028] like Figure 1AAs shown, the exhaust gas purification device 100 includes a first-stage cooling unit 110, a second-stage cooling unit 120 and a filter unit 130, which are connected in sequence and connected to the furnace 118. The first-stage cooling unit 110 and the second-stage cooling unit 120 are used to cool the gas therein to a certain temperature, and the filter unit is used to filter the gas so that a part of it adheres to the filter component. They are connected through pipelines, and by controlling the gas flow path in the exhaust gas purification device, the exhaust gas purification device can work in the exhaust gas purification mode and the self-cleaning mode, and can be maintained in the maintenance mode. Among them, the control device (see Figure 2 ) controls the exhaust gas purification device 100 to switch between the exhaust gas purification mode, the self-cleaning mode and the maintenance mode. In the exhaust gas purification mode, the exhaust gas purification device 100 can purify the exhaust gas discharged from the furnace 118 and transport the purified gas back to the furnace 118; in the self-cleaning mode, the exhaust gas purification device 100 can self-clean the first-stage cooling unit 110, the second-stage cooling unit 120 and the filter unit 130 and the connecting channels therebetween; in the maintenance mode, the exhaust gas purification device 100 can remove the carbon deposited in the filter unit 130 and some organic matter, so that the exhaust gas purification device 100 can be completely dismantled for further cleaning.

[0029] Specifically, the first stage cooling unit 110 has an exhaust gas inlet 111.1, a self-cleaning gas inlet 114, a gas outlet 111.2 and a first waste liquid outlet 141.1, and the second stage cooling unit 120 has a gas inlet 121.1, a gas outlet 121.2 and a waste liquid outlet 141.2, wherein the exhaust gas inlet 111.1 and the self-cleaning gas inlet 114 are connected to the inlet side 184 of the first stage cooling unit 110, and the gas outlet 121.2 is connected to the outlet side 185 of the second stage cooling unit 120. The filter unit 130 has a gas inlet 131.1, a self-cleaning gas outlet 134, a clean gas outlet 131.2 and a waste liquid outlet 141.3.

[0030] The exhaust gas inlet 111.1 of the first stage cooling unit 110 is controllably connected to the high temperature zone fluid of the furnace 118 through the valve component 117.1. The gas outlet 111.2 of the first stage cooling unit 110 is fluidly connected to the gas inlet 121.1 of the second stage cooling unit 120 through the connecting channel 125.1. The gas outlet 121.2 of the second stage cooling unit 120 is fluidly connected to the gas inlet 131.1 of the filter unit 130 through the connecting channel 125.2, and the clean gas outlet 131.2 of the filter unit 130 is controllably connected to the low temperature zone fluid of the furnace 118 through the valve component 117.2. As a result, the exhaust gas discharged from the furnace 118 can be purified by the first stage cooling unit 110, the second stage cooling unit 120 and the filter unit 130 in sequence and then returned to the furnace 118.

[0031] In addition, the self-cleaning gas outlet 134 of the filter unit 130 is connected to the gas inlet 114 of the first-stage cooling unit 110 through a connecting channel 135, and a channel switch component 117.5 is provided on the connecting channel 135 to controllably fluidly connect the self-cleaning gas outlet 134 of the filter unit 130 with the gas inlet 114 of the first-stage cooling unit 110. As a result, the gas discharged from the self-cleaning gas outlet 134 of the filter unit 130 can enter the first-stage cooling unit 110, and can flow through the first-stage cooling unit 110 and the second-stage cooling unit 120 in sequence, and then return to the filter unit 130, so as to form a self-cleaning gas cycle inside the exhaust gas purification device 100.

[0032] According to an embodiment of the present application, the first-stage cooling unit 110 may not be provided with a self-cleaning gas inlet 114 that is separate from the exhaust gas inlet 111.1, but the same inlet may be used as the exhaust gas inlet and the self-cleaning gas inlet. Similarly, the filter unit 130 may not be provided with a self-cleaning gas outlet 134 that is separate from the clean gas outlet 131.2, but the same outlet may be used as the self-cleaning gas outlet 134 and the clean gas outlet 131.2.

[0033] The exhaust gas purification device 100 also includes a gas supply port 112 arranged on the first-stage cooling unit 110 and an exhaust port 132 arranged on the filter unit 130, and a gas concentration detection component for detecting the gas concentration in the filter unit 130. As an example, the gas concentration detection component is an oxygen concentration detection component 155, which detects the oxygen concentration to obtain the concentration of the working gas. Among them, the oxygen concentration detection component 155 is arranged near the exhaust port 132. The gas supply port 112 is controllably opened and closed by the valve component 117.3, and the exhaust port 132 is controllably opened and closed by the valve component 117.4. When the reflow oven uses a substantially inert gas (such as nitrogen) as the working gas, the working gas (i.e., substantially inert gas (such as nitrogen)) can be supplemented to the exhaust gas purification device 100 through the gas supply port 112, and the exhaust port 132 is used to work with the gas supply port 112 when the gas supply port 112 is working. By setting the gas supply port 112 and the exhaust port 132, the concentration of the working gas in the exhaust gas purification device 100 can be adjusted to match the working gas concentration in the furnace 118. The gas supply port 112 can be controllably connected to the working gas (i.e., substantially inert gas (such as nitrogen)) source fluid through the valve component 117.3, and the exhaust port 132 can be controllably connected to the atmospheric fluid through the valve component 117.4.

[0034] The filter unit 130 is provided with a filter component 136. The gas inlet 131.1 of the filter unit 130 is arranged on the upstream side of the filter component 136, and the self-cleaning gas outlet 134 and the clean gas outlet 131.2 are arranged on the downstream side of the filter component 136. It should be noted that the "upstream" and "downstream" here are relative to the gas flow direction in the exhaust gas purification device 100. The filter component 136 can be a steel ball filter or a paper filter.

[0035] The filter unit 130 is also provided with a heating component 133, which is located below the filter component 136 and is used to heat the filter component 136. In the exhaust gas purification mode, the heating component 133 does not heat; in the self-cleaning mode, the heating component 133 can heat the gas in the filter unit 130 to the self-cleaning temperature, so that the pollutants including the soldering flux attached to the filter component 136 undergo physical changes and become liquid or gas; in the maintenance mode, the heating component 133 can heat the gas in the filter unit 130 to the oxidation temperature, so that the carbon attached to the filter component 136 undergoes a chemical reaction (such as an oxidation reaction) to generate gas, and at this temperature, other organic matter attached to the filter component 136 also undergoes a chemical reaction to generate gas. By controlling the heating temperature of the heating component 133, the heating component 133 can heat the gas in the filter unit 130 to the self-cleaning temperature or the oxidation temperature. As a specific example, the self-cleaning temperature can be about 150 to 170°C, and the oxidation temperature can be about 400 to 450°C. When the heating temperature of the heating component 133 is about 400°C, the gas in the filter unit 130 can be heated to the self-cleaning temperature; when the heating temperature of the heating component 133 is about 700°C, the gas in the filter unit 130 can be heated to the oxidation temperature. It should be noted that the self-cleaning temperature and the oxidation temperature may also be set to other specific temperatures as long as the above functions can be met. And it should be understood by those skilled in the art that, depending on the specific structure of the filter unit 130, such as the size of the filter unit 130, and the spacing distance between the filter component 136 and the heating component 133, the heating component 133 may also be set to other heating temperatures to heat the gas in the filter unit to the self-cleaning temperature and the oxidation temperature.

[0036] The exhaust gas purification device 100 further includes a controllable gas channel 181, which is connected to the filter unit 130 through a valve component 182. The valve component 182 is opened only when the exhaust gas purification device 100 is in a maintenance mode, and is used to controllably introduce a gas containing oxygen into the filter unit 130. As an example, the outlet of the gas channel 181 is arranged close to the filter component 136. The inlet of the controllable gas channel 181 is directly connected to the atmosphere, or is connected to a gas source capable of providing oxygen, such as an oxygen cylinder.

[0037] It should be noted that the term "close" here means that the outlet of the controllable gas channel 181 is not far from the filter component 136, or the outlet of the controllable gas channel 181 is directly in fluid communication with the filter component 136. Thus, the oxygen introduced from the outlet of the controllable gas channel 181 into the filter unit 130 can react chemically with the carbon deposited on the filter component 136 and some organic matter.

[0038] The exhaust gas purification device 100 further includes a fan 124 for driving the gas flow in the exhaust gas purification device 100. Figure 1A In the illustrated embodiment, the fan 124 is disposed in the filter unit 130. More specifically, the fan 124 is disposed on the upstream side of the filter component 136, the air inlet side of the fan 124 is in fluid communication with the cavity in the filter unit 130, and the air outlet side of the fan 124 is in fluid communication with the clean air outlet 131.2, the self-cleaning air outlet 134 and the exhaust port 132 of the filter unit 130. In other embodiments, other fluid power devices (such as a blower, a pump, etc.) may be used instead. Figure 1A The fan 124 in the illustrated embodiment only needs to be able to drive the gas in the exhaust gas purification device 100 to flow along a desired path.

[0039] The exhaust gas purification device 100 further includes a collecting unit 140, and the waste liquid outlet 141.1 of the first-stage cooling unit 110, the waste liquid outlet 141.2 of the second-stage cooling unit 120, and the waste liquid outlet 141.3 of the filter unit 130 are all connected to the collecting unit 140, so that the liquid discharged from the first-stage cooling unit 110, the second-stage cooling unit 120, and the filter unit 130 can flow into the collecting unit 140. A valve component 117.6 is provided at the inlet of the collecting unit 140. When the collecting unit 140 needs to be replaced or the liquid in the collecting unit 140 needs to be discharged, the valve component 117.6 can be closed to disconnect the collecting unit 140 from the first-stage cooling unit 110, the second-stage cooling unit 120, and the filter unit 130.

[0040] The exhaust gas purification device 100 further includes temperature detection components 151 , 152 respectively configured to detect the temperature of the gas in the first stage cooling unit 110 and the second stage cooling unit 120 , and a temperature detection component 161 for detecting the temperature of the gas in the filter unit 130 .

[0041] It should be noted that in Figure 1A In the embodiment shown, the exhaust gas purification device 100 includes two-stage cooling units, and the two-stage cooling units are fluidically connected through a connecting channel 125.1. In other embodiments, the exhaust gas purification system may also include only one cooling unit, and the upstream side of the filter unit is fluidically connected to the inlet side of the cooling unit, and the downstream side of the filter unit is fluidically connected to the outlet side of the cooling unit.

[0042] As described above, the exhaust gas purification device 100 has an exhaust gas purification mode, a self-cleaning mode, and a maintenance mode. In the exhaust gas purification mode, the exhaust gas purification device 100 purifies the gas exhausted from the furnace 118 of the reflow soldering furnace. In the self-cleaning mode, the exhaust gas purification device 100 performs self-cleaning on each unit inside the exhaust gas purification device 100 and the connecting pipes. In the maintenance mode, the exhaust gas purification device 100 no longer receives the gas exhausted from the furnace 118 of the reflow soldering furnace, but causes the carbon and some organic matter in the attachments of the filter component 136 to undergo oxidation reaction, so as to facilitate the subsequent disassembly of the exhaust gas purification device 100 for further cleaning using mechanical equipment. By controlling the opening and closing of each valve component 117.1, 117.2, 117.3, 117.4, 117.5, 117.6, 182, the exhaust gas purification device 100 can be switched between the three modes of exhaust gas purification mode, self-cleaning mode, and maintenance mode. The following uses a reflow oven that uses a substantially inert gas (such as nitrogen) as a working gas as an example to illustrate the gas flow paths in the three working modes of the exhaust gas purification device 100 of the present application.

[0043] Figure 1B Shows Figure 1A When the exhaust gas purification device 100 is in the exhaust gas purification mode, the flow path of the gas. Figure 1BAs shown, when the exhaust gas purification device 100 is in the exhaust gas purification mode, the valve components 117.1, 117.2, and 117.6 are opened, the valve components 117.3 and 117.4 are closed, the channel switch component 117.5 can be closed, or at least partially opened, and the valve component 182 is closed to close the gas channel 181. After the exhaust gas (temperature is approximately 170° C.) containing pollutants in the furnace chamber 118 of the reflow soldering furnace is discharged from the high temperature area of ​​the furnace chamber 118, it is first cooled to a first temperature, such as 110 to 130° C., by the first stage cooling unit 110. At this temperature, the organic flux such as rosin in the exhaust gas pollutants in the first stage cooling unit 110 condenses from gaseous state to liquid state and can be discharged from the waste liquid outlet 141.1 of the first stage cooling unit 110 into the collection unit 140, and the remaining part of the exhaust gas is then transported to the second stage cooling unit 120 for further cooling. The gas entering the second stage cooling unit 120 is cooled to a second temperature, for example, 60-80°C, in the second stage cooling unit 120, so that other pollutant organic matter (for example, low-condensing point acid, ester or ether organic matter) in the waste gas condenses from gaseous state to liquid state, and is discharged into the collection unit 140 through the waste liquid outlet 141.2 of the second stage cooling unit 120, and the remaining part of the waste gas is transported to the filter unit 130 for filtration and purification. After the waste gas entering the filter unit 130 is filtered, clean gas is obtained, and the granular and mist organic matter therein is attached to the filter component 136. Finally, the clean gas is transported back to the low temperature zone of the reflow furnace chamber 118 to complete the purification of the waste gas.

[0044] When the exhaust gas purification device 100 is in the exhaust gas purification mode, if the valve component 117.5 is closed, the clean gas filtered by the filter unit 130 cannot be returned to the first-stage cooling unit 110 through the connecting channel 135. If the channel switch component 117.5 is opened or partially opened, a part of the clean gas filtered by the filter unit 130 can be returned to the first-stage cooling unit 110 through the connecting channel 135, thereby, the clean clean gas with a lower temperature in the filter unit 130 can be used to cool the gas in the first-stage cooling unit 110, so as to save the cooling medium used for heat exchange in the first-stage cooling unit 110.

[0045] Figure 1C FIG. 2 shows the flow path of the gas when the exhaust gas purification device 100 is in the self-cleaning mode. Figure 1C As shown, when the exhaust gas purification device 100 is in the self-cleaning mode, valve components 117.3 and 117.4 are closed, valve component 117.6 and channel switch component 117.5 are opened, valve component 182 is closed to close the gas channel 181, and valve components 117.1 and 117.2 can be opened or closed. The figure shows the state where valve components 117.1 and 117.2 are opened. At this time, the control device (see Figure 2) controls the heating temperature of the heating component 133 in the filter unit 130, for example, heating it to about 400°C, so as to heat the gas in the filter unit 130, and raise the gas temperature inside the filter unit 130 to about 150°C to 170°C, for example. Under this temperature, part of the solid pollutants (such as soldering flux) attached to the filter component 136 undergoes physical changes and is converted into a liquid state, and part of it is converted into a gaseous state, wherein the liquid can be discharged through the waste liquid outlet 141.3 of the filter unit 130, and the gas is transported to the first-stage cooling unit 110 and the second-stage cooling unit 120 through the connecting channel 135 at a higher temperature. The gas in the first stage cooling unit 110 and the second stage cooling unit 110 flows back to the filter unit 130 through the connecting channels 125.1, 125.2 as in the above-mentioned waste gas purification process, so that the solid pollutant organic matter attached to the various components in the first stage cooling unit 110 and the second stage cooling unit 120, as well as the inner wall of the connecting channel 125.1 and the cooling channel 125.2 is reheated into liquid or gaseous state, and the liquid is discharged through the waste liquid outlet 141.1 of the first stage cooling unit 110 and the waste liquid outlet 141.2 of the second stage cooling unit 120, and the gas is transported back to the filter unit 130, completing the self-cleaning gas cycle. In addition, in this self-cleaning gas cycle, the local temperature of the filter component 136 near the heating component 133 is relatively high, so that part of the attached matter on the filter component 136 will also undergo a carbonization reaction to obtain a carbonization product, and the carbonization product includes carbon and some small molecular organic matter.

[0046] In such Figure 1C In the self-cleaning gas circulation process shown, if valve components 117.1 and 117.2 are closed, the exhaust gas in the furnace of the reflow soldering furnace cannot enter or exit the exhaust gas purification device 100, and the exhaust gas purification device 100 can perform internal self-cleaning in a relatively independent internal circulation process. If valve components 117.1 and 117.2 are opened, the exhaust gas in the furnace of the reflow soldering furnace can still enter or exit the exhaust gas purification device 100, and the exhaust gas purification device 100 can also perform internal self-cleaning on the exhaust gas in the furnace of the reflow soldering furnace during the internal self-cleaning process. Figure 1B The exhaust gas purification process shown. Therefore, whether the valve components 117.1 and 117.2 are closed or opened, the operation of the reflow oven will not be affected. That is to say, even if the reflow oven is in operation, the exhaust gas purification device 100 can be in the self-cleaning mode to self-clean its interior. According to the needs of actual production, the exhaust gas purification device 100 can be controlled to enter the self-cleaning mode at regular intervals, and the exhaust gas purification device 100 can be cleaned to a certain extent without affecting the operation of the reflow oven.

[0047] Figure 1DFIG. 2 shows the flow path of the gas when the exhaust gas purification device 100 is in the maintenance mode. Figure 1D As shown, when the exhaust gas purification device 100 is in the maintenance mode, the valve components 117.1, 117.2, 117.3, 117.4, and 117.6 are closed, the channel switch component 117.5 is opened, and the valve component 182 is opened to open the gas channel 181. At this time, the heating component 133 in the filter unit 130 can be heated, for example, to about 700°C, to heat the gas in the filter unit 130, and raise the gas temperature inside the filter unit 130 to about 400°C to 450°C. At this temperature, the carbon in the carbonized product deposited on the filter component 136 can undergo an oxidation reaction with the oxygen introduced into the gas channel 181, so that the carbon becomes gas. And at this temperature, the small molecular organic matter in the carbonized product deposited on the filter component 136, and a part of the flux pollutants can also undergo an oxidation reaction with oxygen to generate gas, thereby reducing the amount of organic matter attached to the filter component 136. These gases are then transported to the first stage cooling unit 110 and the second stage cooling unit 120 through the connecting channel 135. The gases in the first stage cooling unit 110 and the second stage cooling unit 110 flow back to the filter unit 130 through the connecting channels 125.1 and 125.2 in the same manner as the self-cleaning gas circulation process described above. Figure 2 ) The heating component 133 is controlled to continue heating for a period of time and then stop heating. After the gas in the exhaust gas purification device 100 cools to room temperature, the exhaust gas purification device 100 can be removed and the exhaust gas purification device 100 can be completely cleaned by mechanical equipment through methods such as ultrasonic cleaning. Among them, the required continuous heating time of the heating component 133 is related to the size of the exhaust gas purification device 100 and the amount of carbon deposited on the filter component 136, and those skilled in the art can pre-set it according to needs.

[0048] According to the inventor's observation and analysis, during the self-cleaning gas circulation process, the heating component 133 needs to heat the gas in the filter unit 130 to the self-cleaning temperature so that the pollutants such as the solder flux in the attachments on the filter component 136 undergo physical changes. However, during this process, a local carbonization reaction will also occur on the filter component 136, and carbonization products including carbon will be produced in the attachments. The accumulated carbon together with other attachments including the solder flux remaining on the filter component 136 may cause a certain degree of blockage of the filter component 136, which on the one hand leads to poor gas circulation in the exhaust gas purification device 100, and on the other hand, affects the temperature of the gas in the cooling unit of the exhaust gas purification device 100 and fails to reach the expected temperature, thereby affecting the exhaust gas purification and self-cleaning effects of the exhaust gas purification device 100, and also affecting the welding effect of the reflow oven.

[0049] In addition, after observation and analysis by the inventors, after a period of use, as pollutants in the exhaust gas purification device 100 continue to accumulate, the entire exhaust gas purification device 100 needs to be cleaned. In order to achieve mechanized operation, a machine is often used for cleaning. For example, a vibrating machine is used to clean the various components of the exhaust gas purification device 100 in a solvent. However, when carbon is attached to the filter component 136, due to the poor solubility of carbon, the cleaning effect of the machine may not meet the cleaning requirements, and manual cleaning may be required.

[0050] In the exhaust gas purification device 100 of the present application, after the self-cleaning mode, oxygen is first introduced into the filter unit 130, and the deposited carbon on the filter component 136 is subjected to high temperature treatment by using the heating component 133, so that the carbon reacts chemically with the introduced oxygen to remove the carbon in the attachments on the filter component 136. In addition, during this process, a portion of other organic matter (including flux and some small molecular organic matter, etc.) attached to the filter component 136 will also undergo oxidation reaction to generate gas. Then, the operator can continue to clean the exhaust gas purification device 100 in a mechanized manner, such as using ultrasonic machine equipment to perform subsequent cleaning of the remaining organic matter in the exhaust gas purification device, which reduces the difficulty of cleaning and can also reduce the amount of solvent used in the cleaning process to a certain extent.

[0051] It can be seen that by controlling the heating component 133 to heat to different heating temperatures, the heating component 133 can heat the gas in the filter unit 130 to the self-cleaning temperature in the self-cleaning mode, so that the pollutants such as flux in the attachments on the filter component 136 undergo physical changes, and can heat the gas in the filter unit 130 to the oxidation temperature in the maintenance mode, so that the carbon deposited on the filter component 136 undergoes a chemical reaction.

[0052] The present application realizes three working modes of the same exhaust gas purification device 100 by controlling the controllable gas channel 181, various valve components and switch components, and using different heating temperatures of the same heating component 133 to heat the gas in the filter unit 130 to different temperatures. And because the exhaust gas purification device 100 of the present application does not need to shut down the reflow oven in the self-cleaning mode, the self-cleaning mode and the maintenance mode are combined to extend the period of shutting down the reflow oven for maintenance.

[0053] As an exemplary technical effect, the self-cleaning mode cycle of the exhaust gas purification device 100 of the present application can be about once a week, and the maintenance mode cycle can be about once a month. It can be seen that the exhaust gas purification device 100 of the present application has a longer maintenance cycle, which can greatly reduce maintenance costs.

[0054] For a reflow soldering furnace that uses a substantially inert gas (e.g., nitrogen) as the working gas, the working gas in the furnace 118 needs to maintain a certain concentration range to meet the process requirements. The reflow soldering furnace is usually provided with a unit for adjusting the concentration of the working gas in the furnace 118 (e.g., a unit for replenishing the working gas). When the exhaust gas purification device 100 is in the exhaust gas purification mode, the gas in the furnace 118 of the reflow soldering furnace is continuously purified by the exhaust gas purification device 100 and sent back to the furnace 118 of the reflow soldering furnace, so the concentration of the working gas in the exhaust gas purification device 100 in the exhaust gas purification mode is similar to the concentration unit of the working gas in the furnace 118 of the reflow soldering furnace. However, when the exhaust gas purification device 100 has been in the maintenance mode and disassembled for cleaning, the concentration of the working gas in the exhaust gas purification device 100 will be less than the concentration of the working gas in the furnace 118. Therefore, according to the present application, after the maintenance mode and cleaning of the exhaust gas purification device 100 are completed, before the exhaust gas purification device 100 is reconnected to the furnace 118 of the reflow soldering furnace, a certain amount of working gas can be added to the exhaust gas purification device 100 so that the working gas in the exhaust gas purification device 100 reaches the same or similar concentration as the working gas in the reflow soldering furnace. To this end, the working gas is added to the exhaust gas purification device 100 through the gas replenishment port 112, and the gas in the exhaust gas purification device 100 is discharged through the exhaust port 132 at the same time, until the oxygen concentration detection component 155 determines that the concentration of the protective gas in the exhaust gas purification device 100 reaches the concentration of the protective gas in the reflow soldering furnace.

[0055] When the exhaust gas purification device 100 is used in a reflow oven that uses air as the working gas, the gas purified by the exhaust gas purification device 100 may be transported back to the furnace 118, or may not be transported back to the furnace 118 but may be directly discharged into the atmosphere. If the gas purified by the exhaust gas purification device 100 is directly discharged into the atmosphere, then Figure 1B The clean gas outlet 131 . 2 of the filter unit 130 is shown to be controllably connected to the atmospheric fluid via a valve member 117 . 2 rather than being connected to the furnace 118 .

[0056] According to the present application, the first-stage cooling unit 110 and the second-stage cooling unit 120 in the exhaust gas purification device 100 may adopt any type of known heat exchange device.

[0057] According to the present application, the first-stage cooling unit 110, the second-stage cooling unit 120 and the filter unit 130 of the exhaust gas purification device 100 can be integrated together so that the entire exhaust gas purification device 100 forms a box-type exhaust gas purification device for use with a reflow oven.

[0058] Figure 22 shows a block diagram of the control device 260 of the exhaust gas purification device 100. The control device 260 includes a bus 262, a processor 264, an input interface 266, an output interface 268, and a memory 274 having a control program 276. The processor 264, the input interface 266, the output interface 268, and the memory 274 are communicatively connected via the bus 262, so that the processor 264 can control the operation of the input interface 266, the output interface 268, and the memory 274. The memory 274 is used to store programs, instructions, and data, and the processor 264 reads programs, instructions, and data from the memory 274, and can write data to the memory 274.

[0059] The input interface 266 receives signals and data through the connection 278, such as the temperature signals detected by the temperature detection components 151, 152, 161, the oxygen concentration signals detected by the oxygen concentration detection component 155, and various parameters and control instructions input manually. The output interface 268 sends signals and data through the connection 272, such as the control signals for controlling the switches of various valve components 117.1, 117.2, 117.3, 117.4 and 182 and the channel switch component 117.5, and the control signals for controlling the heating temperature of the heating component 133. The memory 274 stores control programs and data. Various parameters can be set in advance in the production process, or they can be set by manual input or data import when in use. The processor 264 obtains various signals, data, programs and instructions from the input interface 266 and the memory 274, performs corresponding processing, and outputs them through the output interface 268.

[0060] Although the present application will be described with reference to the specific embodiments shown in the accompanying drawings, it should be understood that the exhaust gas purification device of the present application can have many variations without departing from the spirit, scope and background of the teachings of the present application. Those of ordinary skill in the art will also be aware that there are different ways to change the settings in the embodiments disclosed in the present application, all of which fall within the spirit and scope of the present application and claims.

Claims

1. An exhaust gas purification device (100) for purifying exhaust gas in a reflow oven, characterized in that include: A filter unit (130); a filter component (136), wherein the filter component (136) is disposed in the filter unit (130); a controllable gas passage (181), the controllable gas passage (181) controllably connecting the interior of the filter unit (130) with the exterior containing oxygen, the controllable gas passage (181) being configured to: controllably introduce gas containing oxygen into the filter unit (130); a heating component (133), the heating component (133) being disposed in the filtering unit (130); and a control device (260), the control device (260) being configured to control the heating temperature of the heating component (133) so that the heating component (133) can heat the gas in the filter unit (130) to an oxidation temperature or a self-cleaning temperature; Wherein, the control device (260) is configured to control the exhaust gas purification device (100) to have a self-cleaning mode and a maintenance mode; The control device (260) is configured to control the controllable gas channel (181) to be closed in the self-cleaning mode, and to control the heating component (133) to heat the gas in the filter unit (130) to the self-cleaning temperature, so that the soldering flux in the attachment on the filter component (136) undergoes a physical change and becomes liquid or gas, and charcoal is generated in the attachment; and The control device (260) is configured to control the controllable gas channel (181) to be opened in the maintenance mode, and to control the heating component (133) to heat the gas in the filter unit (130) to the oxidation temperature, so that the carbon in the attachment on the filter component (136) undergoes a chemical reaction to generate gas.

2. The exhaust gas purification device (100) according to claim 1, characterized in that: The exhaust gas purification device (100) comprises an exhaust gas inlet (111.1) and a clean gas outlet (131.2), the upstream side of the filter component (136) is in fluid communication with the exhaust gas inlet (111.1), and the downstream side of the filter component (136) is in fluid communication with the clean gas outlet (131.2); Wherein, the heating component (133) is arranged on the upstream side of the filtering component (136).

3. The exhaust gas purification device (100) according to claim 1, characterized in that: The filter unit (130) further comprises a waste liquid outlet (141.3), and the waste liquid outlet (141.3) is configured to guide the waste liquid to flow from the filter component to the collection unit (140).

4. The exhaust gas purification device (100) according to claim 3, characterized in that: The control device (260) is configured to control the exhaust gas purification device (100) to further have an exhaust gas purification mode; The control device (260) is configured to control the controllable gas channel (181) to be closed in the exhaust gas purification mode, so that the exhaust gas in the reflow furnace chamber is filtered through the filter component (136), and during the filtering process, attachments including soldering flux remain on the filter component (136).

5. The exhaust gas purification device (100) according to claim 4, characterized in that: The controllable gas channel (181) is configured such that an outlet of the controllable gas channel (181) is close to the filter component (136).

6. The exhaust gas purification device (100) according to claim 3, characterized in that: After the carbon in the deposits on the filter element (136) undergoes a chemical change to generate gas, the exhaust gas purification device (100) is cleaned by a mechanical device.

7. The exhaust gas purification device (100) according to claim 1, characterized in that Also includes: a cooling unit configured to cool exhaust gas received through an exhaust gas inlet of the cooling unit and supply the cooled exhaust gas to the filtering unit; and / or a fluid power device, the fluid power device being configured to drive the gas in the exhaust gas purification device to flow through the filter unit, wherein the fluid power device comprises a fan, a blower or a pump; and / or The filter component (136) is located upstream of the fluid power device, and / or the downstream side of the filter component (136) is in communication with the fluid power device.

8. The exhaust gas purification device (100) according to claim 1, characterized in that: The oxidation temperature is higher than the self-cleaning temperature.

9. The exhaust gas purification device (100) according to claim 8, characterized in that: The oxidation temperature is 400-450°C.

10. The exhaust gas purification device (100) according to claim 8, characterized in that: The self-cleaning temperature is 150-170°C.

11. The exhaust gas purification device (100) according to claim 1, characterized in that: At the oxidation temperature, part of the organic matter in the deposits on the filter element (136) can also undergo chemical changes to generate gas.

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