Technical Field

The present application relates to the field of soldering and, in particular, to a reflow oven for processing electronic components.

Background Art

A reflow oven is used to solder components on circuit boards. Specifically, a reflow oven has a heating zone and a cooling zone. The heating zone is used to heat the circuit board to melt the solder paste (e.g., tin paste) on the circuit board into a liquid state. The cooling zone is used to solidify the liquid solder paste into a solid state, thereby allowing the solder paste to be solidified on selected areas of the circuit board to solder electronic components to the circuit board.

Summary of Invention

The present application provides a reflow oven, comprising a heating zone, a cooling zone, a barrier exhaust zone, a fluid channel, a diversion device, a detection device, and a regulation device, wherein the cooling zone is disposed downstream of the heating zone; the barrier exhaust zone is disposed between the heating zone and the cooling zone; the fluid channel comprises a fluid channel inlet and a fluid channel outlet, of which the fluid channel inlet is connected to the barrier exhaust zone; the diversion device is connected to the fluid channel and is capable of directing the flow of fluid in the fluid channel from the fluid channel inlet to the fluid channel outlet; the detection device is configured to measure the parameters of the gas inside the diversion device; and the regulation device is connected to the diversion device and is capable of receiving signals from the detection device to regulate the gas flow within the diversion device based on the received signals.

In the reflow oven as described above, the diversion device is a Venturi throat.

In the reflow oven as described above, the reflow oven further comprises a control device communicatively connected to the detection device; wherein the detection device is configured to send detection signals to the control device, and the control device is capable of receiving the detection signals emitted by the detection device.

In the reflow oven as described above, the regulation device is a flow regulating valve.

In the reflow oven as described above, the control device is communicatively connected to the regulation device, and the control device is configured to control the flow of the flow regulating valve through a PID algorithm.

In the reflow oven as described above, the reflow oven further comprises: a purification device communicatively connected to the diversion device, and the purification device is capable of purifying impurities in the gas in the fluid channel.

In the reflow oven as described above, the reflow oven further comprises: an alarm device communicatively connected to the control device, wherein the control device is configured to be capable of making judgments based on signals received from the regulation device and the detection device and sending signals to the alarm device to emit an alarm based on the judgment results.

In the reflow oven as described above, the detection device comprises a differential pressure detector for detecting the pressure difference between the pressure of the gas at the inlet of the diversion device and the atmospheric pressure.

In the reflow oven as described above, the channel outlet of the fluid channel is disposed at the end of the cooling zone and is capable of forming an air curtain; the working atmosphere of the reflow oven is nitrogen gas.

In the reflow oven as described above, the purification device has a working mode and a maintenance mode, wherein in the working mode, the fluid flow of the diversion device is set at a first predetermined range; in the maintenance mode, the fluid flow in the diversion device is set at a second predetermined range, and the first predetermined range is greater than the second predetermined range.

The reflow oven in the present application has a heating zone, a barrier exhaust zone and a cooling zone. The components to be processed inside the reflow oven pass sequentially through the heating zone, the barrier exhaust zone and the cooling zone. The reflow oven further comprises a diversion device, as well as a detection device and a regulation device. The diversion device is capable of drawing a portion of the impurity-containing gas from the barrier exhaust zone to prevent excessive impurities from contaminating the cooling zone. The detection device and the regulation device are connected to the control system, of which the detection device is capable of detecting the gas pressure in the diversion device and sending a signal to the control system, and the control system is capable of adjusting the gas flow in the diversion device according to the received signal. The diversion device in the present application is not prone to clogging.

Brief Description of Drawings

Figure 1 is a simplified system diagram of a reflow oven according to an example of the present application;

Figure 2 is a simplified schematic diagram of an example of the control device in Figure 1.

Figure 3 is a schematic sectional diagram of the diversion device in the present application;

Figure 4 is a three-dimensional view of the diversion device, regulation device, detection device, and purification unit in the present application.

Specific Embodiments

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,” 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 attached 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.

Figure 1 is a system diagram of a reflow oven according to an example of the present application; As shown in Figure 1, the reflow oven 100 comprises a soldering section 101, a purification section 102, and a furnace chamber 104. The furnace chamber 104 runs through the soldering section 101, and comprises a furnace chamber inlet 142 and a furnace chamber outlet 144. The reflow oven 100 is also provided with a conveying member (not shown in the drawings), which runs through the furnace chamber 104 and is used to convey the processing element to be processed, such as a circuit board. The conveying member is capable of feeding circuit boards into the furnace chamber 104 from the furnace chamber inlet 142 of the furnace chamber 104, and outputting circuit boards which have been processed by the reflow oven 100 from the furnace chamber 104 through the furnace chamber outlet 144 of the furnace chamber 104.

As shown in Figure 1, the soldering section 101 comprises a heating zone 110, a barrier exhaust zone 130, and a cooling zone 120. The furnace chamber 104 is disposed transversely through the heating zone 110, the barrier exhaust zone 130, and the cooling zone 120, such that the heating zone 110, the barrier exhaust zone 130 and the cooling zone 120 are fluidly connected. The processing element is transported by the conveying member and enter the reflow oven 100 from the heating zone inlet 151, passes sequentially through the heating zone 110, the barrier exhaust zone 130, and the cooling zone 120, and then leaves the reflow oven 100 via the cooling zone outlet 156. In an example of this application, the reflow oven is used to solder circuit boards and electronic elements together, with a tin paste between the electronic element and the circuit board, and the reflow oven 100 is capable of heating the tin paste to melt it, thereby connecting the circuit board and the electronic element.

The heating zone 110 and the cooling zone 120 may each comprise a plurality of units. In the example shown in Figure 1, the heating zone 110 comprises eight heating units Z1 - Z8, each of which is connected to adjacent heating units only through the furnace chamber 104. The temperature of each of the eight units may be set according to processing requirements. The heating zone 110 is used to provide a higher temperature to the processing element to melt the solder paste. The cooling zone 120 comprises two cooling units Cl - C2. The cooling zone 120 is used to cool the processed element after it has been heated by the heating zone 110. After the processing element is transported from the heating zone 110 into the cooling zone 120, the solder paste is cooled and solidified on the soldering area of the processing element, thereby connecting the electronic component to the circuit board. Notably, the number of soldering units in the heating zone 110 and the cooling zone 120 of the reflow oven may be configured according to the required process requirements and is not limited to the example shown in Figure 1.

The reflow oven 100 further comprises an inlet zone Bl and an outlet zone B2, wherein the inlet zone Bl and the outlet zone B2 are disposed at each end of the soldering section 101. The inlet zone B 1 and the outlet zone B2 are used in the nitrogen mode to provide airflow towards the furnace chamber inlet 142 and the furnace chamber outlet 144 in the furnace chamber 104 to form an air curtain, through which air from the external environment can be blocked from entering the furnace chamber 104, thereby maintaining the purity of the inert working atmosphere in the reflow furnace 100.

The purification section 102 comprises a plurality of purification units (Pl - P6), each of which is connected to heating units Z1 - Z8, the barrier exhaust zone 130, or the cooling units Cl - C2, for purifying gases from the welding section 101. The gas in the soldering section 101 is purified by the purification units and then returned to the soldering section 101 or discharged from the soldering section 101. For example, each of the purification units Pl - P5 is connected to the heating units Z1 - Z8 or the cooling units Cl - C2 in the soldering section 101 via an inlet line and an outlet line, and the gas in the soldering section 101 enters the corresponding purification unit via the inlet line and returns to the soldering section from the outlet line. One end of the purification unit P6 is connected to the barrier exhaust zone 130 and the other end is connected to the outlet zone B2. In an example of the present application, the purification device 180 comprises a purification unit P6.

Each purification unit is provided with a catalytic device and a heating device (not shown in the drawings), and the catalytic device is provided with a catalyst, which catalyzes the decomposition of volatile pollutants in the flux into components that do not condense easily, thus enabling the furnace chamber 104 to remain clean for a longer period of time and avoiding contamination of the circuit board. The heating device has a catalytic mode and a maintenance mode. In the catalytic mode, the temperature setting of the heating device ensures that the temperature inside the purification unit is suitable for catalytically decomposing pollutants in the flux; in the maintenance mode, the temperature setting of the heating device is such that the temperature in the purification unit is capable of activating the catalyst on the catalytic unit.

The total number of purification units may be equal to or less than the sum of the total number of heating units and cooling units. In the present application, the total number of heating units and cooling units is 10 and the total number of purification units is 6.

After the circuit board enters the reflow oven 100 through the furnace chamber inlet 142, the circuit board can be gradually heated in the heating zone 110, and at least a portion of the pollutants in the flux in the solder paste on the processing element will be vaporized at high temperature. The cooling zone 120 is used to reduce the heated circuit board to a suitable temperature and then send it out of the reflow oven. If the gas in the heating zone 110 directly enters the cooling zone 120, the substantial heat could impact the cooling effectiveness of the cooling zone 120. At the same time, the flux in the gas might condense due to the temperature drop and potentially drip onto the circuit boards, affecting the processing quality of the circuit board. Therefore, a barrier exhaust zone 130 is provided between the heating zone 110 and the cooling zone 120, and a fluid channel 115 is provided between the barrier exhaust zone 130 and the outlet zone B2, wherein the fluid channel 115 is capable of drawing at least a portion of the gas from the barrier exhaust zone 130 to prevent the influx of a large amount of gas from the heating zone 110 into the cooling zone 120.

The reflow oven 100 further comprises a fluid channel 115 and a diversion device 170. The fluid channel 115 comprises a fluid channel inlet 161 and a fluid channel outlet 162. The fluid channel inlet 161 is connected to the barrier exhaust outlet 159 such that the fluid channel 115 is connected to the barrier exhaust zone 130. A diversion device 170 is provided in the fluid channel 115 for providing power to draw gas out of the barrier exhaust zone 130. In an example of the present application, the diversion device 170 is a Venturi throat. The purification unit P6 is disposed in the fluid channel 115, and the diversion device 170 is located downstream of the purification unit P6. The gas in the barrier exhaust zone 130 may be guided by the diversion device 170, sequentially pass through the fluid passage inlet 161, purification unit P6, diversion device 170, and fluid passage outlet. In an example of the present application, the working atmosphere of the reflow oven is nitrogen gas, and the fluid channel outlet 162 of the fluid channel 115 is connected to the outlet zone B2 to form an air curtain to prevent gas loss inside the furnace chamber.

The reflow oven 100 further comprises a detection device 111. The detection end of the detection device 111 is disposed in the diversion device 170 and is capable of detecting the parameters of the gas in the diversion device 170, which may reflect the clogging of the diversion device 170. In an example of the present application, the detection device 111 is a differential pressure detection device, such as a differential pressure gauge, for detecting the difference between the pressure of the gas at the inlet of the diversion device 170 and the atmospheric pressure at the location of the differential pressure detection device.

It is to be noted that although the detection device 111 in the example of the present application is a differential pressure detection device, it is understood by those skilled in the art that the detection device 111 may also be a pressure detection device for detecting the pressure of the gas in the fluid channel 115. It will also be appreciated by those skilled in the art that the detection device 111 may also be a flow detection device for detecting the gas flow in the fluid channel 115. Clogging in the diversion device 170 is determined based on the value of the gas flow in the fluid channel 115.

The reflow oven 100 further comprises a regulation device 112. The regulation device 112 is provided to be connected to the diversion device 170. The regulation device 112 is capable of receiving signals from the detection device 111 to regulate the gas flow within the diversion device 170. In an example of the present application, the regulation device 112 is a flow regulator valve, such as a proportional valve. By regulating the degree of opening of the proportional valve, the gas flow through the diversion device 170 can be adjusted. The proportional valve regulates the degree of opening of the proportional valve by means of a PID algorithm based on the signal received from the detection device 111 regarding the differential pressure.

The reflow oven 100 further comprises a control device 140. The control device 140 is communicatively connected to the detection device 111 and the regulation device 112. The detection device 111 is capable of providing detection signals to the control device 140. The regulation device 112 is capable of receiving signals from the control device 140 and regulating the gas flow within the diversion device 170 based on the received signals.

The inventors have found through long-term observation that after the reflow oven has been operating for an extended period of time, there will be residues on circuit boards output from the outlet of the cooling zone that have been soldered. The inventors have analyzed and found that such residues are liquid flux or solid rosin in liquid flux. The presence of such residues reduces the quality of the circuit boards. After the reflow oven is operated for a longer period of time, the amount of such residues can increase and even reduce the yield of the circuit boards. The inventors further analyzed this situation and concluded that it is due to insufficient gas flow across the channel between the barrier exhaust zone 130 and the outlet zone B2. Specifically, a diversion device, such as a Venturi throat, is provided in the fluid channel between the barrier exhaust zone 130 and the outlet zone B2. The temperature in the heating zone is higher and generally reaches 280 °C. When gaseous flux is drawn from the barrier exhaust area and reaches the diversion device, the gaseous flux will condense into solid flux due to the temperature drop and adhere to the inner wall of the diversion device. Over time, the flow area of the diversion device will decrease due to the adhesion of solid flux, causing a reduction in the gas flow within the diversion device and affecting the exhaust effect of the barrier exhaust zone. When the gas flow in the diversion device decreases and the flow slows down, solid flux is more likely to condense, further accelerating the rate at which the diversion device becomes clogged. At the same time, the diversion device is connected to a purification unit, and the gas flow in the purification unit is reduced, which is not conducive to the heat discharge of the heating device in the purification unit and reduces the service life of the heating device. Therefore, the gas flow in the diversion device needs to reach a first predetermined value to ensure that a sufficient amount of gas is drawn from the barrier exhaust zone 130.

In addition, the purification unit P6 connected to the diversion device has a working mode and a maintenance mode. In the working mode, the temperature is approximately 280 °C, and in the maintenance mode, the temperature is approximately 400 °C. When the purification unit P6 is switched to the maintenance mode, a smaller gas flow is required in the purification unit P6 to prevent excessive heat loss, so that the temperature in the purification unit P6 does not reach 400 °C. Therefore, in the maintenance mode, the gas flow in the diversion device needs to be less than the second predetermined value, so as to ensure that the temperature in the purification unit P6 can be maintained.

The flow of the diversion device 170 in the reflow oven 100 of the present application can be adjusted by the regulation device 112 such that the gas flow in the diversion device 170 is in an appropriate range, for example, the gas flow in the diversion device can be controlled between a first predetermined value and a second predetermined value. In the working mode of the purification unit P6, the diversion device 170 in the reflow oven 100 of the present application is capable of drawing gaseous flux from the barrier exhaust zone 130 in sufficient quantity to effectively prevent gaseous flux from condensing into solid flux and prevent an influx of gaseous flux from entering the cooling zone 120, thereby ensuring the production quality of circuit boards and improving the yield rate of circuit boards. In the maintenance mode of the purification unit P6, the gas flow in the drainage device 170 is smaller, such that the temperature in the purification unit P6 can be maintained.

Figure 2 is a simplified schematic diagram of an example of the control device 140 in Figure 1. As shown in Figure 2, the control device 140 comprises a bus 202, a processor 204, an input interface 206, an output interface 208, and a memory 214 having a control program 216. The various components of the control device 140, including the processor 204, the input interface 206, the output interface 208 and the memory 214 are connected to the bus 202, such that the processor 204 is capable of controlling the operation of the input interface 206, the output interface 208 and the memory 214. Specifically, the memory 214 is used to store programs, instructions, and data, while the processor 204 reads programs, instructions, and data from the memory 214 and is capable of writing data to the memory 214.

The input interface 206 receives external signals and data via the wire 218, including detection signals sent from the detection device 111. The output interface 208 sends control signals externally via the wire 222, including control signals to the regulation device 112 for changing the degree of opening. The memory 214 of the control device 140 stores data such as a control program and a preset target setting values. Various parameters may be preset in the manufacturing process, or may be set by manual input or data import during use.

Figure 3 is a schematic sectional diagram of the diversion device in the present application. The diversion device 170 of the present application is provided on the fluid channel 115 to accelerate the exhaust velocity of the barrier exhaust zone 130. According to an example of the present application, the diversion device 170 of the present application is a Venturi throat shown in Figure 3. The diversion device 170 comprises a compressed gas line 350 comprising a compressed gas inlet pipe 349 and a compressed gas exhaust pipe 348. The compressed gas inlet pipe 349 is connected to a high pressure gas source, and the compressed gas line 350 is capable of introducing high pressure gas into the diversion device 170. The diversion device 170 comprises a body 310. The body 310 comprises a body inlet 311 and a body outlet 312, and the body 310 is connected to the fluid channel 115, wherein the body inlet 311 is positioned toward the barrier exhaust zone 130, the body outlet 312 is positioned toward the outlet zone B2, and gas flows in the body 310 in the direction indicated by arrow 388. The compressed gas exhaust pipe 348 extends into the body 310 in the same direction as the extension direction of the body 310. The outlet 335 of the compressed gas exhaust pipe 348 is positioned toward the body outlet 312 such that the gas discharged from the outlet 235 of the compressed gas exhaust pipe 348 flows in the direction shown by the arrow 388, i.e., the direction of flow of the gas discharged from the outlet 235 of the compressed gas exhaust pipe 348 is in the same direction as that of the gas in the body 310.

In the example shown in Figure 3, the diameter of the compressed gas exhaust pipe 348 is much smaller than the diameter of the body 310, and when compressed gas is conveyed through the diversion device 170, the diversion device 170 forms a low-pressure or even vacuum region 390 at the outlet 335 of the compressed gas exhaust pipe 348 such that gas in the body 310 flows from the body inlet 311 to the region 390, i.e., the gas in the body 310 flows along the direction of the body inlet 311 to the body outlet 312, and the diversion device 170 is able to direct the flow of gas in the fluid channel 115.

The gas flow in the body 310 is associated with the flow of the gas discharged from the outlet

355 of the compressed gas exhaust pipe 348. When the gas flow in the compressed gas exhaust pipe 348 increases, the gas flow in the body 310 increases; when the gas flow in the compressed gas exhaust pipe 348 decreases, the gas flow in the body 310 decreases. The gas flow in the body 310 may be adjusted by adjusting the gas flow in the compressed gas line 350. When the gas flow in the body 310 is increased, the flux is less likely to accumulate on the inner wall of the body 310, and the body 310 is less likely to be clogged.

Figure 4 is a three-dimensional view of the diversion device, regulation device, detection device, and purification unit in the present application. As shown in Figure 4, the purification unit P6 has an inlet end 411 and an outlet end 412, wherein the inlet end 411 is connected to the barrier exhaust zone 130 and the outlet end 412 is connected to the diversion device 170. The purification unit P6 is provided with a heating device that is capable of heating and breaking down a portion of solid flux, which serves to purify the gas. However, the purification unit P6 cannot break down all of the solid flux, and a portion of the solid flux will enter the body 310 of the diversion device 170 and adhere to the inner wall of the body 310 of the diversion device 170.

The body inlet 311 of the body 310 of the diversion device 170 is connected to the outlet end 412 of the purification unit P6, and the body outlet 312 is connected to the outlet zone B2 through a pipeline.

The detection device 111 comprises a detector 421 and a detection line 422 through which the detector 421 is connected to the outlet end 412 of the purification unit P6 and is capable of detecting the pressure difference between the gas at the outlet end 412 and the atmospheric pressure. The outlet end 412 is proximate to and connected to the body inlet 311 of the body 310 of the diversion device 170, such that the gas pressure difference at the outlet end 412 reflects the gas pressure at the body inlet 311 of the body 310 of the diversion device 170. The gas pressure difference at the body inlet 311 can reflect the clogging of the body 310.

The regulation device 112 is connected to the compressed gas line 250 of the diversion device 170, and the regulation device 112 comprises a proportional valve 470, the degree of opening of which enables 0 - 100 % regulation, which enables the regulation of the flow of the high-pressure gas entering the compressed gas line 250. Both the detection device 111 and the regulation device 112 are communicatively connected to the control device 140, and the detection device 111 sends signals reflecting the gas pressure difference at the body inlet 311 to the control device 140. The control device 140 uses the received differential pressure signal to determine whether the gas flow within the body 310 corresponds to the current pressure difference.

When the purification unit of the reflow oven is in the working mode, the gas flow in the diversion device 170 needs to reach a first predetermined value. In an example of the present application, the first predetermined value is 12 m ³ /h (cubic meters per hour), and the differential pressure detected by the detection device 111 is 50 kPa when the gas flow in the body 310 is 12 m ³ /h.

In the working mode, when the gas flow in the body 310 is greater than the first predetermined value, the control device 140 sends a signal to the regulation device 112 to maintain the current degree of opening of the proportional valve 470. When the gas flow in the body 310 is lower than the first predetermined value, the control device 140 sends a signal to the regulation device 112 to increase the degree of opening of the proportional valve 470. When the proportional valve 470 has maintained a 100% degree of opening for a period of time and the gas flow in the body 310 is still lower than the first predetermined value, the regulation device 112 will send a signal to the control device 140, and the control device 140 will activate the alarm device 116 to emit an alarm indicating that the diversion device 170 is severely clogged and requires maintenance.

When the purification unit of the reflow oven is in the maintenance mode, it is usually necessary to raise the temperature of the heating device in the purification unit to 400 °C. At this point, it is necessary to control the gas flow in the control body 310 to be less than the second predetermined value and greater than the third predetermined value, so as to avoid too much heat from being taken away by excessive gas flow, which could result in an inability to maintain the internal temperature of the purification unit at 400 °C. Conversely, if the gas flow is too low, it could lead to excessively high internal temperatures within the purification unit. In an example of the present application, the second predetermined value is 1.5 m ³ /h (cubic meters per hour), the third predetermined value is 0.5 m ³ /h (cubic meters per hour), and the gas flow in the diversion device 170 is 1 m ³ /h (cubic meters per hour) in the maintenance mode.

In the maintenance mode, when the gas flow in the body 310 is greater than the second predetermined value, the control device 140 sends a signal to the regulation device 112 to reduce the current degree of opening of the proportional valve 470. When the gas flow in the body 310 is lower than the third predetermined value, the control device 140 sends a signal to the regulation device 112 to increase the degree of opening of the proportional valve 470, such that the gas flow in the body 310 is between the second predetermined value and the third predetermined value.

The reflow oven in the present application is capable of detecting the gas flow in the diversion device 170 at any time through the combined action of the detection device 111, the regulation device 112, and the control device 140, such that the gas in the barrier exhaust zone 130 can be discharged smoothly. At the same time, this prevents the diversion device 170 from becoming more prone to clogging due to excessively low flow in the diversion device 170. Additionally, the gas flow rate in the diversion device 170 can be adjusted to accommodate the maintenance mode of the purification unit.

Although the present disclosure has been described in connection with examples of the implementations 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. In addition, the technical effects and/or technical problems described in the present specification are exemplary and not limiting; therefore, the disclosure in the present specification may be used to solve other technical problems and have other technical effects and [text cut-off]. 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. 1

REFLOW OVEN

Technical Field

The present application relates to the field of soldering and, in particular, to a reflow oven for processing electronic components.

Background Art

A reflow oven is used to solder components on circuit boards. Specifically, a reflow oven has a heating zone and a cooling zone. The heating zone is used to heat the circuit board to melt the solder paste (e.g., tin paste) on the circuit board into a liquid state. The cooling zone is used to solidify the liquid solder paste into a solid state, thereby allowing the solder paste to be solidified on selected areas of the circuit board to solder electronic components to the circuit board.

Summary of Invention

The present application provides a reflow oven, comprising a heating zone, a cooling zone, a barrier exhaust zone, a fluid channel, a diversion device, a detection device, and a regulation device, wherein the cooling zone is disposed downstream of the heating zone; the barrier exhaust zone is disposed between the heating zone and the cooling zone; the fluid channel comprises a fluid channel inlet and a fluid channel outlet, of which the fluid channel inlet is connected to the barrier exhaust zone; the diversion device is connected to the fluid channel and is capable of directing the flow of fluid in the fluid channel from the fluid channel inlet to the fluid channel outlet; the detection device is configured to measure the parameters of the gas inside the diversion device; and the regulation device is connected to the diversion device and is capable of receiving signals from the detection device to regulate the gas flow within the diversion device based on the received signals.

In the reflow oven as described above, the diversion device is a Venturi throat.

In the reflow oven as described above, the reflow oven further comprises a control device communicatively connected to the detection device; wherein the detection device is configured to 2 send detection signals to the control device, and the control device is capable of receiving the detection signals emitted by the detection device.

In the reflow oven as described above, the regulation device is a flow regulating valve.

In the reflow oven as described above, the control device is communicatively connected to the regulation device, and the control device is configured to control the flow of the flow regulating valve through a PID algorithm.

In the reflow oven as described above, the reflow oven further comprises: a purification device communicatively connected to the diversion device, and the purification device is capable of purifying impurities in the gas in the fluid channel.

In the reflow oven as described above, the reflow oven further comprises: an alarm device communicatively connected to the control device, wherein the control device is configured to be capable of making judgments based on signals received from the regulation device and the detection device and sending signals to the alarm device to emit an alarm based on the judgment results.

In the reflow oven as described above, the detection device comprises a differential pressure detector for detecting the pressure difference between the pressure of the gas at the inlet of the diversion device and the atmospheric pressure.

In the reflow oven as described above, the channel outlet of the fluid channel is disposed at the end of the cooling zone and is capable of forming an air curtain; the working atmosphere of the reflow oven is nitrogen gas.

In the reflow oven as described above, the purification device has a working mode and a maintenance mode, wherein in the working mode, the fluid flow of the diversion device is set at a first predetermined range; in the maintenance mode, the fluid flow in the diversion device is set at a second predetermined range, and the first predetermined range is greater than the second predetermined range.

The reflow oven in the present application has a heating zone, a barrier exhaust zone and a cooling zone. The components to be processed inside the reflow oven pass sequentially through the heating zone, the barrier exhaust zone and the cooling zone. The reflow oven further comprises a 3 diversion device, as well as a detection device and a regulation device. The diversion device is capable of drawing a portion of the impurity-containing gas from the barrier exhaust zone to prevent excessive impurities from contaminating the cooling zone. The detection device and the regulation device are connected to the control system, of which the detection device is capable of detecting the gas pressure in the diversion device and sending a signal to the control system, and the control system is capable of adjusting the gas flow in the diversion device according to the received signal. The diversion device in the present application is not prone to clogging.

Brief Description of Drawings

Figure 1 is a simplified system diagram of a reflow oven according to an example of the present application;

Figure 2 is a simplified schematic diagram of an example of the control device in Figure 1.

Figure 3 is a schematic sectional diagram of the diversion device in the present application;

Figure 4 is a three-dimensional view of the diversion device, regulation device, detection device, and purification unit in the present application.

Specific Embodiments

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,” 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 attached 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.

Figure 1 is a system diagram of a reflow oven according to an example of the present application; As shown in Figure 1, the reflow oven 100 comprises a soldering section 101, a purification section 102, and a furnace chamber 104. The furnace chamber 104 runs through the 4 soldering section 101, and comprises a furnace chamber inlet 142 and a furnace chamber outlet 144. The reflow oven 100 is also provided with a conveying member (not shown in the drawings), which runs through the furnace chamber 104 and is used to convey the processing element to be processed, such as a circuit board. The conveying member is capable of feeding circuit boards into the furnace chamber 104 from the furnace chamber inlet 142 of the furnace chamber 104, and outputting circuit boards which have been processed by the reflow oven 100 from the furnace chamber 104 through the furnace chamber outlet 144 of the furnace chamber 104.

As shown in Figure 1, the soldering section 101 comprises a heating zone 110, a barrier exhaust zone 130, and a cooling zone 120. The furnace chamber 104 is disposed transversely through the heating zone 110, the barrier exhaust zone 130, and the cooling zone 120, such that the heating zone 110, the barrier exhaust zone 130 and the cooling zone 120 are fluidly connected. The processing element is transported by the conveying member and enter the reflow oven 100 from the heating zone inlet 151, passes sequentially through the heating zone 110, the barrier exhaust zone 130, and the cooling zone 120, and then leaves the reflow oven 100 via the cooling zone outlet 156. In an example of this application, the reflow oven is used to solder circuit boards and electronic elements together, with a tin paste between the electronic element and the circuit board, and the reflow oven 100 is capable of heating the tin paste to melt it, thereby connecting the circuit board and the electronic element.

The heating zone 110 and the cooling zone 120 may each comprise a plurality of units. In the example shown in Figure 1, the heating zone 110 comprises eight heating units Z1 - Z8, each of which is connected to adjacent heating units only through the furnace chamber 104. The temperature of each of the eight units may be set according to processing requirements. The heating zone 110 is used to provide a higher temperature to the processing element to melt the solder paste. The cooling zone 120 comprises two cooling units Cl - C2. The cooling zone 120 is used to cool the processed element after it has been heated by the heating zone 110. After the processing element is transported from the heating zone 110 into the cooling zone 120, the solder paste is cooled and solidified on the soldering area of the processing element, thereby connecting the electronic component to the circuit board. 5

Notably, the number of soldering units in the heating zone 110 and the cooling zone 120 of the reflow oven may be configured according to the required process requirements and is not limited to the example shown in Figure 1.

The reflow oven 100 further comprises an inlet zone Bl and an outlet zone B2, wherein the inlet zone Bl and the outlet zone B2 are disposed at each end of the soldering section 101. The inlet zone B 1 and the outlet zone B2 are used in the nitrogen mode to provide airflow towards the furnace chamber inlet 142 and the furnace chamber outlet 144 in the furnace chamber 104 to form an air curtain, through which air from the external environment can be blocked from entering the furnace chamber 104, thereby maintaining the purity of the inert working atmosphere in the reflow furnace 100.

The purification section 102 comprises a plurality of purification units (Pl - P6), each of which is connected to heating units Z1 - Z8, the barrier exhaust zone 130, or the cooling units Cl - C2, for purifying gases from the welding section 101. The gas in the soldering section 101 is purified by the purification units and then returned to the soldering section 101 or discharged from the soldering section 101. For example, each of the purification units Pl - P5 is connected to the heating units Z1 - Z8 or the cooling units Cl - C2 in the soldering section 101 via an inlet line and an outlet line, and the gas in the soldering section 101 enters the corresponding purification unit via the inlet line and returns to the soldering section from the outlet line. One end of the purification unit P6 is connected to the barrier exhaust zone 130 and the other end is connected to the outlet zone B2. In an example of the present application, the purification device 180 comprises a purification unit P6.

Each purification unit is provided with a catalytic device and a heating device (not shown in the drawings), and the catalytic device is provided with a catalyst, which catalyzes the decomposition of volatile pollutants in the flux into components that do not condense easily, thus enabling the furnace chamber 104 to remain clean for a longer period of time and avoiding contamination of the circuit board. The heating device has a catalytic mode and a maintenance mode. In the catalytic mode, the temperature setting of the heating device ensures that the temperature inside the purification unit is suitable for catalytically decomposing pollutants in the 6 flux; in the maintenance mode, the temperature setting of the heating device is such that the temperature in the purification unit is capable of activating the catalyst on the catalytic unit.

The total number of purification units may be equal to or less than the sum of the total number of heating units and cooling units. In the present application, the total number of heating units and cooling units is 10 and the total number of purification units is 6.

After the circuit board enters the reflow oven 100 through the furnace chamber inlet 142, the circuit board can be gradually heated in the heating zone 110, and at least a portion of the pollutants in the flux in the solder paste on the processing element will be vaporized at high temperature. The cooling zone 120 is used to reduce the heated circuit board to a suitable temperature and then send it out of the reflow oven. If the gas in the heating zone 110 directly enters the cooling zone 120, the substantial heat could impact the cooling effectiveness of the cooling zone 120. At the same time, the flux in the gas might condense due to the temperature drop and potentially drip onto the circuit boards, affecting the processing quality of the circuit board. Therefore, a barrier exhaust zone 130 is provided between the heating zone 110 and the cooling zone 120, and a fluid channel 115 is provided between the barrier exhaust zone 130 and the outlet zone B2, wherein the fluid channel 115 is capable of drawing at least a portion of the gas from the barrier exhaust zone 130 to prevent the influx of a large amount of gas from the heating zone 110 into the cooling zone 120.

The reflow oven 100 further comprises a fluid channel 115 and a diversion device 170. The fluid channel 115 comprises a fluid channel inlet 161 and a fluid channel outlet 162. The fluid channel inlet 161 is connected to the barrier exhaust outlet 159 such that the fluid channel 115 is connected to the barrier exhaust zone 130. A diversion device 170 is provided in the fluid channel 115 for providing power to draw gas out of the barrier exhaust zone 130. In an example of the present application, the diversion device 170 is a Venturi throat. The purification unit P6 is disposed in the fluid channel 115, and the diversion device 170 is located downstream of the purification unit P6. The gas in the barrier exhaust zone 130 may be guided by the diversion device 170, sequentially pass through the fluid passage inlet 161, purification unit P6, diversion device 170, and fluid passage outlet. 7

In an example of the present application, the working atmosphere of the reflow oven is nitrogen gas, and the fluid channel outlet 162 of the fluid channel 115 is connected to the outlet zone B2 to form an air curtain to prevent gas loss inside the furnace chamber.

The reflow oven 100 further comprises a detection device 111. The detection end of the detection device 111 is disposed in the diversion device 170 and is capable of detecting the parameters of the gas in the diversion device 170, which may reflect the clogging of the diversion device 170. In an example of the present application, the detection device 111 is a differential pressure detection device, such as a differential pressure gauge, for detecting the difference between the pressure of the gas at the inlet of the diversion device 170 and the atmospheric pressure at the location of the differential pressure detection device.

It is to be noted that although the detection device 111 in the example of the present application is a differential pressure detection device, it is understood by those skilled in the art that the detection device 111 may also be a pressure detection device for detecting the pressure of the gas in the fluid channel 115. It will also be appreciated by those skilled in the art that the detection device 111 may also be a flow detection device for detecting the gas flow in the fluid channel 115. Clogging in the diversion device 170 is determined based on the value of the gas flow in the fluid channel 115.

The reflow oven 100 further comprises a regulation device 112. The regulation device 112 is provided to be connected to the diversion device 170. The regulation device 112 is capable of receiving signals from the detection device 111 to regulate the gas flow within the diversion device 170. In an example of the present application, the regulation device 112 is a flow regulator valve, such as a proportional valve. By regulating the degree of opening of the proportional valve, the gas flow through the diversion device 170 can be adjusted. The proportional valve regulates the degree of opening of the proportional valve by means of a PID algorithm based on the signal received from the detection device 111 regarding the differential pressure.

The reflow oven 100 further comprises a control device 140. The control device 140 is communicatively connected to the detection device 111 and the regulation device 112. The detection device 111 is capable of providing detection signals to the control device 140. The 8 regulation device 112 is capable of receiving signals from the control device 140 and regulating the gas flow within the diversion device 170 based on the received signals.

The inventors have found through long-term observation that after the reflow oven has been operating for an extended period of time, there will be residues on circuit boards output from the outlet of the cooling zone that have been soldered. The inventors have analyzed and found that such residues are liquid flux or solid rosin in liquid flux. The presence of such residues reduces the quality of the circuit boards. After the reflow oven is operated for a longer period of time, the amount of such residues can increase and even reduce the yield of the circuit boards. The inventors further analyzed this situation and concluded that it is due to insufficient gas flow across the channel between the barrier exhaust zone 130 and the outlet zone B2. Specifically, a diversion device, such as a Venturi throat, is provided in the fluid channel between the barrier exhaust zone 130 and the outlet zone B2. The temperature in the heating zone is higher and generally reaches 280 °C. When gaseous flux is drawn from the barrier exhaust area and reaches the diversion device, the gaseous flux will condense into solid flux due to the temperature drop and adhere to the inner wall of the diversion device. Over time, the flow area of the diversion device will decrease due to the adhesion of solid flux, causing a reduction in the gas flow within the diversion device and affecting the exhaust effect of the barrier exhaust zone. When the gas flow in the diversion device decreases and the flow slows down, solid flux is more likely to condense, further accelerating the rate at which the diversion device becomes clogged. At the same time, the diversion device is connected to a purification unit, and the gas flow in the purification unit is reduced, which is not conducive to the heat discharge of the heating device in the purification unit and reduces the service life of the heating device. Therefore, the gas flow in the diversion device needs to reach a first predetermined value to ensure that a sufficient amount of gas is drawn from the barrier exhaust zone 130.

In addition, the purification unit P6 connected to the diversion device has a working mode and a maintenance mode. In the working mode, the temperature is approximately 280 °C, and in the maintenance mode, the temperature is approximately 400 °C. When the purification unit P6 is switched to the maintenance mode, a smaller gas flow is required in the purification unit P6 to prevent excessive heat loss, so that the temperature in the purification unit P6 does not reach 9

400 °C. Therefore, in the maintenance mode, the gas flow in the diversion device needs to be less than the second predetermined value, so as to ensure that the temperature in the purification unit P6 can be maintained.

The flow of the diversion device 170 in the reflow oven 100 of the present application can be adjusted by the regulation device 112 such that the gas flow in the diversion device 170 is in an appropriate range, for example, the gas flow in the diversion device can be controlled between a first predetermined value and a second predetermined value. In the working mode of the purification unit P6, the diversion device 170 in the reflow oven 100 of the present application is capable of drawing gaseous flux from the barrier exhaust zone 130 in sufficient quantity to effectively prevent gaseous flux from condensing into solid flux and prevent an influx of gaseous flux from entering the cooling zone 120, thereby ensuring the production quality of circuit boards and improving the yield rate of circuit boards. In the maintenance mode of the purification unit P6, the gas flow in the drainage device 170 is smaller, such that the temperature in the purification unit P6 can be maintained.

Figure 2 is a simplified schematic diagram of an example of the control device 140 in Figure 1. As shown in Figure 2, the control device 140 comprises a bus 202, a processor 204, an input interface 206, an output interface 208, and a memory 214 having a control program 216. The various components of the control device 140, including the processor 204, the input interface 206, the output interface 208 and the memory 214 are connected to the bus 202, such that the processor 204 is capable of controlling the operation of the input interface 206, the output interface 208 and the memory 214. Specifically, the memory 214 is used to store programs, instructions, and data, while the processor 204 reads programs, instructions, and data from the memory 214 and is capable of writing data to the memory 214.

The input interface 206 receives external signals and data via the wire 218, including detection signals sent from the detection device 111. The output interface 208 sends control signals externally via the wire 222, including control signals to the regulation device 112 for changing the degree of opening. The memory 214 of the control device 140 stores data such as a control program and a preset 10 target setting values. Various parameters may be preset in the manufacturing process, or may be set by manual input or data import during use.

Figure 3 is a schematic sectional diagram of the diversion device in the present application. The diversion device 170 of the present application is provided on the fluid channel 115 to accelerate the exhaust velocity of the barrier exhaust zone 130. According to an example of the present application, the diversion device 170 of the present application is a Venturi throat shown in Figure 3. The diversion device 170 comprises a compressed gas line 350 comprising a compressed gas inlet pipe 349 and a compressed gas exhaust pipe 348. The compressed gas inlet pipe 349 is connected to a high pressure gas source, and the compressed gas line 350 is capable of introducing high pressure gas into the diversion device 170. The diversion device 170 comprises a body 310. The body 310 comprises a body inlet 311 and a body outlet 312, and the body 310 is connected to the fluid channel 115, wherein the body inlet 311 is positioned toward the barrier exhaust zone 130, the body outlet 312 is positioned toward the outlet zone B2, and gas flows in the body 310 in the direction indicated by arrow 388. The compressed gas exhaust pipe 348 extends into the body 310 in the same direction as the extension direction of the body 310. The outlet 335 of the compressed gas exhaust pipe 348 is positioned toward the body outlet 312 such that the gas discharged from the outlet 235 of the compressed gas exhaust pipe 348 flows in the direction shown by the arrow 388, i.e., the direction of flow of the gas discharged from the outlet 235 of the compressed gas exhaust pipe 348 is in the same direction as that of the gas in the body 310.

In the example shown in Figure 3, the diameter of the compressed gas exhaust pipe 348 is much smaller than the diameter of the body 310, and when compressed gas is conveyed through the diversion device 170, the diversion device 170 forms a low-pressure or even vacuum region 390 at the outlet 335 of the compressed gas exhaust pipe 348 such that gas in the body 310 flows from the body inlet 311 to the region 390, i.e., the gas in the body 310 flows along the direction of the body inlet 311 to the body outlet 312, and the diversion device 170 is able to direct the flow of gas in the fluid channel 115.

The gas flow in the body 310 is associated with the flow of the gas discharged from the outlet

355 of the compressed gas exhaust pipe 348. When the gas flow in the compressed gas exhaust pipe 11

348 increases, the gas flow in the body 310 increases; when the gas flow in the compressed gas exhaust pipe 348 decreases, the gas flow in the body 310 decreases. The gas flow in the body 310 may be adjusted by adjusting the gas flow in the compressed gas line 350. When the gas flow in the body 310 is increased, the flux is less likely to accumulate on the inner wall of the body 310, and the body 310 is less likely to be clogged.

Figure 4 is a three-dimensional view of the diversion device, regulation device, detection device, and purification unit in the present application. As shown in Figure 4, the purification unit P6 has an inlet end 411 and an outlet end 412, wherein the inlet end 411 is connected to the barrier exhaust zone 130 and the outlet end 412 is connected to the diversion device 170. The purification unit P6 is provided with a heating device that is capable of heating and breaking down a portion of solid flux, which serves to purify the gas. However, the purification unit P6 cannot break down all of the solid flux, and a portion of the solid flux will enter the body 310 of the diversion device 170 and adhere to the inner wall of the body 310 of the diversion device 170.

The body inlet 311 of the body 310 of the diversion device 170 is connected to the outlet end 412 of the purification unit P6, and the body outlet 312 is connected to the outlet zone B2 through a pipeline.

The detection device 111 comprises a detector 421 and a detection line 422 through which the detector 421 is connected to the outlet end 412 of the purification unit P6 and is capable of detecting the pressure difference between the gas at the outlet end 412 and the atmospheric pressure. The outlet end 412 is proximate to and connected to the body inlet 311 of the body 310 of the diversion device 170, such that the gas pressure difference at the outlet end 412 reflects the gas pressure at the body inlet 311 of the body 310 of the diversion device 170. The gas pressure difference at the body inlet 311 can reflect the clogging of the body 310.

The regulation device 112 is connected to the compressed gas line 250 of the diversion device 170, and the regulation device 112 comprises a proportional valve 470, the degree of opening of which enables 0 - 100 % regulation, which enables the regulation of the flow of the high-pressure gas entering the compressed gas line 250. 12

Both the detection device 111 and the regulation device 112 are communicatively connected to the control device 140, and the detection device 111 sends signals reflecting the gas pressure difference at the body inlet 311 to the control device 140. The control device 140 uses the received differential pressure signal to determine whether the gas flow within the body 310 corresponds to the current pressure difference.

When the purification unit of the reflow oven is in the working mode, the gas flow in the diversion device 170 needs to reach a first predetermined value. In an example of the present application, the first predetermined value is 12 m ³ /h (cubic meters per hour), and the differential pressure detected by the detection device 111 is 50 kPa when the gas flow in the body 310 is 12 m ³ /h.

In the working mode, when the gas flow in the body 310 is greater than the first predetermined value, the control device 140 sends a signal to the regulation device 112 to maintain the current degree of opening of the proportional valve 470. When the gas flow in the body 310 is lower than the first predetermined value, the control device 140 sends a signal to the regulation device 112 to increase the degree of opening of the proportional valve 470. When the proportional valve 470 has maintained a 100% degree of opening for a period of time and the gas flow in the body 310 is still lower than the first predetermined value, the regulation device 112 will send a signal to the control device 140, and the control device 140 will activate the alarm device 116 to emit an alarm indicating that the diversion device 170 is severely clogged and requires maintenance.

When the purification unit of the reflow oven is in the maintenance mode, it is usually necessary to raise the temperature of the heating device in the purification unit to 400 °C. At this point, it is necessary to control the gas flow in the control body 310 to be less than the second predetermined value and greater than the third predetermined value, so as to avoid too much heat from being taken away by excessive gas flow, which could result in an inability to maintain the internal temperature of the purification unit at 400 °C. Conversely, if the gas flow is too low, it could lead to excessively high internal temperatures within the purification unit. In an example of the present application, the second predetermined value is 1.5 m ³ /h (cubic meters per hour), the 13 third predetermined value is 0.5 m ³ /h (cubic meters per hour), and the gas flow in the diversion device 170 is 1 m ³ /h (cubic meters per hour) in the maintenance mode.

In the maintenance mode, when the gas flow in the body 310 is greater than the second predetermined value, the control device 140 sends a signal to the regulation device 112 to reduce the current degree of opening of the proportional valve 470. When the gas flow in the body 310 is lower than the third predetermined value, the control device 140 sends a signal to the regulation device 112 to increase the degree of opening of the proportional valve 470, such that the gas flow in the body 310 is between the second predetermined value and the third predetermined value.

The reflow oven in the present application is capable of detecting the gas flow in the diversion device 170 at any time through the combined action of the detection device 111, the regulation device 112, and the control device 140, such that the gas in the barrier exhaust zone 130 can be discharged smoothly. At the same time, this prevents the diversion device 170 from becoming more prone to clogging due to excessively low flow in the diversion device 170. Additionally, the gas flow rate in the diversion device 170 can be adjusted to accommodate the maintenance mode of the purification unit.

Although the present disclosure has been described in connection with examples of the implementations 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. In addition, the technical effects and/or technical problems described in the present specification are exemplary and not limiting; therefore, the disclosure in the present specification may be used to solve other technical problems and have other technical effects and [text cut-off]. 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.