An on-line vapor phase soldering apparatus with vapor phase liquid recycling

Abstract

This application provides an online vapor phase welding equipment with vapor-liquid recycling, relating to the field of vapor phase welding technology. It includes: a preheating chamber, a reduction chamber, a welding chamber, and a cooling chamber arranged sequentially along the workpiece conveying direction; a closed-loop vapor-liquid circulation pipeline system including a vacuum pipeline, a condensation recovery device, a storage tank, and a circulation pump; the input end of the vacuum pipeline is connected to both the preheating chamber and the welding chamber, and its output end is connected to the inlet of the condensation recovery device, used to draw uncondensed vapor phase liquid vapor from the preheating chamber and the welding chamber to the condensation recovery device; the condensation recovery device is used to condense the vapor phase liquid vapor into a liquid medium, and its outlet is connected to the storage tank; the outlet of the storage tank is connected to the inlet of the preheating chamber and the welding chamber via the circulation pump, so as to pump the recovered liquid medium back into the chamber, forming a closed-loop recycling of the vapor phase liquid. This equipment significantly improves temperature uniformity and effectively reduces the consumption of vapor phase liquid medium, lowering waste liquid treatment costs.

Description

Technical Field

[0001] This invention belongs to the field of vapor phase welding technology, specifically relating to an online vapor phase welding device that utilizes vapor phase liquid recycling. Background Technology

[0002] In the field of semiconductor welding, the batch welding of power semiconductor devices, ball grid array devices, and multilayer PCBs requires high temperature uniformity and welding reliability.

[0003] Existing welding equipment mostly employs contact heating, where a heating plate is placed at the bottom of the chamber and raised by a lifting mechanism to contact the workpiece tray, relying on heat conduction from the heating rods to heat the product. This method suffers from significant temperature uniformity defects—the area where the heating plate contacts the tray is hotter, while the non-contact areas are colder. This is especially problematic for large-area substrates or multi-layer PCBs, where the large temperature gradient can easily lead to inconsistent solder joint quality and compromised welding reliability. Furthermore, existing equipment consumes a large amount of heating media during production, resulting in high operating costs.

[0004] Therefore, how to improve the temperature uniformity during the welding process while reducing equipment operating costs is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] In view of the above-mentioned defects or deficiencies in the prior art, a preheating chamber, a reduction chamber, a welding chamber and a cooling chamber are provided in sequence along the workpiece conveying direction; Also includes: Vapor-liquid closed-loop circulation piping system: including vacuum piping, condensation recovery device, liquid storage tank and circulation pump; The input end of the vacuum pipeline is connected to the preheating chamber and the welding chamber respectively, and its output end is connected to the inlet of the condensation recovery device, which is used to draw the uncondensed vapor phase liquid vapor in the preheating chamber and the welding chamber to the condensation recovery device. The condensation recovery device is used to condense vapor phase liquid vapor into liquid medium, and its outlet is connected to the storage tank; The outlet of the storage tank is connected to the inlet of the preheating chamber and the welding chamber via the circulation pump, so as to pump the recovered liquid medium back into the chamber to form a closed-loop recycling of vapor phase liquid.

[0006] According to the technical solution provided in this application, the interior of the reduction chamber is provided with a heating plate, and at least one support rod is fixedly connected to the bottom surface of the heating plate. The support rod passes through the bottom wall of the reduction chamber in a sealed manner and is connected to a lifting drive assembly located outside the reduction chamber. The lifting drive assembly drives the heating plate to move up and down between a low position and a high position through the support rod. When the heating plate is in the high position, its upper surface contacts the workpiece tray that enters the reduction chamber.

[0007] According to the technical solution provided in this application, both the preheating chamber and the welding chamber are equipped with an upper heating element, a lower heating element, and a side heating element. The upper heating element is located on the inner top wall of the chamber, the lower heating element is located on the inner bottom wall of the chamber, and the side heating element is located on the inner side wall of the chamber. The projections of the upper heating element and the lower heating element on the horizontal plane are arranged perpendicular to each other to form a grid-like spatial heating field.

[0008] According to the technical solution provided in this application, a temperature measuring device is provided inside the preheating chamber and / or the welding chamber, and the temperature measuring device includes: A temperature measuring bracket is fixedly installed on the inner bottom wall of the cabin. A temperature measuring base is installed on the temperature measuring bracket; A temperature-sensing contact copper block is movably mounted on the temperature-sensing base via a guide portion. A high-temperature spring is fitted on the guide portion so that the temperature-sensing contact copper block can elastically float along the axial direction of the guide portion. A temperature-sensing thermocouple is installed at the bottom of the temperature-sensing contact copper block; The temperature-measuring contact copper block has a flat middle section and beveled ends. When the workpiece tray passes by, the beveled ends guide the tray to gradually compress the high-temperature spring, eventually making it tightly fit against the flat middle section.

[0009] According to the technical solution provided in this application, the lifting drive assembly includes a lifting sub-plate, the lifting sub-plate having at least two flange ends, and a chuck seat fixed on each flange end; the lower end of each support rod passes through one of the chuck seats and is detachably fastened by a nut; each chuck seat has a threaded hole at its bottom end, and a leveling screw is screwed into the threaded hole from bottom to top, with the top end of the leveling screw abutting against the lower end face of the corresponding support rod.

[0010] According to the technical solution provided in this application, the bottom of the preheating chamber and / or the welding chamber is connected to a liquid inlet tee. The first end of the liquid inlet tee is connected to an inert gas pipeline through a flow regulating valve, the second end is connected to a vapor-liquid pipeline through an on / off valve, and the third end is connected to the interior of the chamber. The flow regulating valve and the on / off valve are arranged in parallel to realize single injection or mixed injection of vapor-liquid and inert gas.

[0011] According to the technical solution provided in this application, the vacuum pipeline includes a main pipeline and branch pipelines arranged in parallel; a first pneumatic baffle valve is connected in series on the main pipeline, and a second pneumatic baffle valve and a suction regulating valve are connected in series on the branch pipelines; the main pipeline forms a fast suction path, and the branch pipelines form a slow suction path with adjustable flow rate.

[0012] According to the technical solution provided in this application, the lifting drive assembly further includes a strut beam fixed to the top of the strut, and the heating plate is supported on the strut beam; the strut beam is provided with three positioning pins, and the heating plate is provided with three through holes, and the heating plate is sleeved on the positioning pins through the through holes for limiting; wherein, the installation height of the middle positioning pin among the three positioning pins is higher than that of the positioning pins on both sides, so that after the heating plate is installed, the two sides of the heating plate have height adjustment space relative to the strut beam.

[0013] According to the technical solution provided in this application, the temperature measuring bracket has an elongated hole, the length of which extends vertically; the temperature measuring base is mounted on the temperature measuring bracket at an adjustable height by fasteners passing through the elongated hole, so as to adjust the height of the temperature measuring contact copper block relative to the workpiece tray feeding plane.

[0014] According to the technical solution provided in this application, a heat insulation protective cover for the hatch is provided above the upper heating element. The heat insulation protective cover for the hatch covers the outer surface of the hatch cover of the preheating chamber and / or welding chamber, and is detachably fastened to the hatch cover by a plucked handle.

[0015] Compared with the prior art, the beneficial effects of this application are as follows: I. Significantly Improved Temperature Uniformity. Both the preheating chamber and the welding chamber use vapor-liquid steam as the heating medium. Saturated steam can evenly penetrate to all surfaces of the workpiece and narrow gaps and deep holes. Heat is transferred evenly through convection and condensation, fundamentally eliminating the temperature gradient problem caused by local contact between the heating plate and the tray in existing contact heating methods.

[0016] Second, operating costs are significantly reduced. By setting up a vapor-liquid closed-loop circulation pipeline system consisting of vacuum pipelines, condensation recovery devices, storage tanks, and circulation pumps, the uncondensed vapor in the preheating chamber and welding chamber is centrally extracted, condensed, recovered, and pumped back into the two chambers for reuse, effectively reducing the consumption of vapor-liquid media and lowering waste liquid treatment costs.

[0017] Third, high production efficiency. The preheating chamber, reduction chamber, welding chamber, and cooling chamber are arranged sequentially along the workpiece conveying direction. Each chamber can independently and in parallel execute its corresponding process, realizing continuous online operation and significantly shortening the production cycle of a single batch. Attached Figure Description

[0018] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 A schematic diagram of the structure of the online vapor phase welding equipment for vapor-liquid recycling provided in this application; Figure 2 A diagram showing the positional relationship between the preheating chamber, reduction chamber, welding chamber, and cooling chamber provided for this application; Figure 3 This is a schematic diagram of the structure of the heating plate provided in this application; Figure 4 This is a schematic diagram of the lifting drive assembly provided in this application; Figure 5 This is a schematic diagram of the structure of the chuck provided in this application; Figure 6 This is a structural schematic diagram of the liquid inlet tee for the cabin provided in this application; Figure 7 A schematic diagram of the temperature measuring device provided in this application; Figure 8 A schematic diagram of the structure of the upper heating element, side heating element and lower heating element provided in this application.

[0019] The text labels in the image represent: 1. Installation platform; 2. Preheating chamber; 3. Reduction chamber; 31. Heating plate; 32. Support rod; 33. Lifting drive assembly; 34. Support rod crossbeam; 35. Chuck seat; 36. Leveling screw; 37. Positioning pin; 4. Welding chamber; 41. Chamber inlet tee; 42. Upper heating element; 43. Side heating element; 44. Lower heating element; 5. Cooling chamber; 6. Temperature measuring device; 61. Temperature measuring contact copper block; 62. High temperature spring; 63. Guide part; 64. Temperature measuring base; 65. Temperature measuring thermocouple; 66. Temperature measuring bracket; 7. Smoke device. Detailed Implementation

[0020] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] As mentioned in the background section, this application proposes an online vapor phase welding device that utilizes vapor-liquid recycling, such as... Figure 1-8 As shown, the preheating chamber 2, reduction chamber 3, welding chamber 4, and cooling chamber 5 are arranged sequentially along the workpiece conveying direction; Also includes: Vapor-liquid closed-loop circulation piping system: including vacuum piping, condensation recovery device, liquid storage tank and circulation pump; The input end of the vacuum pipeline is connected to the preheating chamber 2 and the welding chamber 4 respectively, and its output end is connected to the inlet of the condensation recovery device, which is used to draw the uncondensed vapor phase liquid vapor in the preheating chamber 2 and the welding chamber 4 to the condensation recovery device. The condensation recovery device is used to condense vapor phase liquid vapor into liquid medium, and its outlet is connected to the storage tank; The outlet of the storage tank is connected to the inlet of the preheating chamber 2 and the welding chamber 4 via the circulation pump, so as to pump the recovered liquid medium back into the chamber to form a closed-loop recycling of vapor phase liquid.

[0023] Specifically, the equipment includes an installation platform 1 and four independent process compartments arranged sequentially along the workpiece conveying direction: a preheating compartment 2, a reduction compartment 3, a welding compartment 4, and a cooling compartment 5. The installation platform 1 consists of a frame and the outer shell of the entire machine, providing the mounting foundation for each compartment and auxiliary components. The preheating compartment 2, reduction compartment 3, welding compartment 4, and cooling compartment 5 are arranged in a straight line. Workpieces are carried by pallets and enter each compartment sequentially along the conveying direction to complete the preheating, reduction, welding, and cooling processes, respectively, realizing continuous online production.

[0024] One of the core improvements of this invention is the establishment of a closed-loop vapor-liquid circulation pipeline system. This system consists of four core components connected sequentially: a vacuum pipeline, a condensation recovery device, a storage tank, and a circulation pump. Specifically, the vacuum pipeline has an input end and an output end. Its input end is connected via pipes to the top interfaces of the preheating chamber 2 and the welding chamber 4, specifically to KF40 connectors located at the top of the chambers. The output end of the vacuum pipeline is connected to the inlet of the condensation recovery device. The condensation recovery device itself has an inlet and an outlet. Its inlet receives vapor-liquid vapor transported from the vacuum pipeline, and its outlet is connected via a pipe to the inlet of the storage tank. The storage tank is used to collect and temporarily store the liquid medium formed after condensation. The outlet of the storage tank is connected via a pipe to the inlet of the circulation pump. The outlet of the circulation pump is connected via a liquid supply pipeline to the liquid inlet ends of the preheating chamber 2 and the welding chamber 4, specifically at the liquid inlet tee 41 of the chamber.

[0025] During equipment operation, after liquid vapor phase is injected into preheating chamber 2 and welding chamber 4, the heating elements inside the chamber heat and vaporize the liquid medium, forming a saturated vapor atmosphere to heat the workpiece. During this process, some of the vapor phase does not condense on the workpiece surface but diffuses in gaseous form within the chamber space. At this time, the vacuum pipeline is activated to extract the uncondensed vapor phase from the top of the two chambers and transport it along the vacuum pipeline to the condensation recovery device. The condensation recovery device cools the high-temperature vapor phase through heat exchange, causing it to recondense from a gaseous state into a liquid medium. The liquid medium flows out from the outlet of the condensation recovery device and enters a storage tank for temporary storage. When preheating chamber 2 or welding chamber 4 needs to be injected with medium again, the circulation pump is activated, pumping the liquid medium in the storage tank back to the inlet of the two chambers through the supply pipeline. The medium is then heated and vaporized again to participate in the welding or preheating process. Thus, the vacuum pipeline draws exhaust gas from the cabin, the condensation and recovery device converts the exhaust gas into liquid, the storage tank collects the liquid medium, and the circulation pump pumps the medium back to the cabin. These four components work together to form a closed-loop circulation system.

[0026] The technical problem solved by this closed-loop circulation pipeline system is the high consumption and significant waste of media in existing online multi-compartment vapor phase welding equipment. Since both the preheating compartment 2 and the welding compartment 4 require continuous consumption of vapor phase liquid to maintain a saturated steam atmosphere, if an open discharge method is used, the uncondensed steam discharged from both compartments is directly vented into the air, and the media cannot be recovered, resulting in high production costs. This invention constructs a unified closed-loop recovery pipeline to centrally collect, uniformly process, and reuse the uncondensed steam discharged from both compartments, enabling the media to circulate within the system. Only a small amount of loss due to open compartment leakage needs to be replenished to maintain production operation, significantly improving media utilization.

[0027] The technical advantages achieved by this solution are that the two vapor phase medium consumption units, preheating chamber 2 and welding chamber 4, share the same set of recovery and circulation pipelines. This results in a compact system structure and a rational pipeline layout, avoiding equipment redundancy and increased floor space caused by configuring separate recovery devices for each chamber. Simultaneously, the closed-loop circulation method significantly reduces medium loss, decreasing both the procurement cost of vapor phase liquid and preventing direct emission of medium-containing waste gas, thus achieving a balance between economic and environmental benefits. Furthermore, because the condensation recovery device is connected to the storage tank, the storage tank to the circulation pump, and the circulation pump to the chamber inlet via sealed pipelines, the entire circulation path is isolated from the outside atmosphere, effectively preventing oxygen and moisture from entering the system and ensuring medium purity and process stability.

[0028] In a preferred embodiment, the interior of the reduction chamber 3 is provided with a heating plate 31, and at least one support rod 32 is fixedly connected to the bottom surface of the heating plate 31. The support rod 32 passes through the bottom wall of the reduction chamber 3 in a downward sealed manner and is connected to a lifting drive assembly 33 located outside the reduction chamber 3. The lifting drive assembly 33 drives the heating plate 31 to move up and down between a low position and a high position through the support rod 32. When the heating plate 31 is in the high position, its upper surface contacts the workpiece tray that enters the reduction chamber 3.

[0029] Specifically, the reduction chamber 3 is located between the preheating chamber 2 and the welding chamber 4. Its function is to remove the oxide layer on the surface of the workpiece pads and leads under a reducing atmosphere, providing a clean metal surface for subsequent welding processes. Unlike the preheating chamber 2 and the welding chamber 4, which use vapor-liquid heating, the reduction chamber 3 uses contact heat conduction heating.

[0030] The reduction chamber 3 has a heating plate 31 installed inside, which is horizontally positioned in the lower part of the chamber. An electric heating element is embedded within the heating plate 31, generating heat when electricity is applied. At least one support rod 32 is fixedly connected to the bottom surface of the heating plate 31. The support rod 32 is a slender, vertically oriented rod, with its upper end fixed to the bottom surface of the heating plate 31 by welding or threaded connection, and its lower end extending downwards through the bottom wall of the reduction chamber 3 to the outside of the chamber. To ensure the chamber's sealing performance, a lifting sealing flange is installed where the support rod 32 passes through the bottom wall. The sealing flange contains a linear bearing and seals, ensuring smooth axial sliding of the support rod 32 while preventing leakage of the reducing atmosphere from the perforation.

[0031] A lifting drive assembly 33 is installed outside the reduction chamber 3, in the space below the bottom wall of the chamber. This lifting drive assembly 33 is connected to the lower end of a support rod 32 extending through the bottom of the chamber, and can drive the support rod 32 to move vertically up and down. When the lifting drive assembly 33 drives the support rod 32 upward, the support rod 32 pushes the heating plate 31 from a low position to a high position; when the lifting drive assembly 33 drives the support rod 32 downward, the heating plate 31 falls back from a high position to a low position. When the heating plate 31 is in the low position, there is a gap between its upper surface and the lower surface of the workpiece tray, allowing the workpiece tray to freely enter or leave the reduction chamber 3 without obstruction. When the workpiece tray reaches the designated position inside the reduction chamber 3, the lifting drive assembly 33 activates, raising the heating plate 31 to the high position. Its upper surface then contacts the lower surface of the workpiece tray, and the heat generated inside the heating plate 31 is directly transferred to the tray through heat conduction at the contact interface, and then from the tray to the workpiece, uniformly heating the workpiece.

[0032] The actual operation of the reduction chamber 3 is as follows: After the product and pallet complete the preheating process, they are conveyed into the reduction chamber 3 by the conveyor mechanism and remain in the predetermined position. At this time, the heating plate 31 is in a low-position waiting state, maintaining a safe distance from the pallet. After the position sensor confirms that the pallet is in place, the servo motor starts, driving the lifting plate to rise through the reducer and ball screw pair. The lifting plate drives the support rod 32 and the heating plate 31 to rise together. The heating plate 31 gradually approaches the lower surface of the pallet and finally makes contact with it under a certain pressure. The heating plate 31 is preheated to the process set temperature, and after contact, the heat is quickly transferred to the pallet and the workpiece. At the same time, a reducing atmosphere such as formic acid vapor is introduced into the reduction chamber 3. Under the combined action of high temperature and reducing atmosphere, the metal oxides on the surface of the solder pads and leads are reduced to pure metal, the solder wettability is improved, and the solder can spread fully during subsequent soldering, reducing the internal void defects of the solder joint.

[0033] The technical problem this structure aims to solve is that the reduction process requires the coordinated action of both heating and atmosphere. However, if vapor-liquid heating is used in the reduction chamber 3, the vapor may react with or dilute the formic acid atmosphere, affecting the reduction effect. Therefore, the reduction chamber 3 is independently configured with a contact heating method, where heating and atmosphere supply are independent and do not interfere with each other. Simultaneously, the height-adjustable design of the heating plate 31 meets the requirements of continuous production: the heating plate 31 needs to make room when the pallet enters or exits, and it needs to be in close contact during heating operations to ensure heat transfer efficiency. This structure balances the needs of smooth material conveying and good heating effect by switching between low-position waiting and high-position contact states.

[0034] In a preferred embodiment, both the preheating chamber 2 and the welding chamber 4 are provided with an upper heating element 42, a lower heating element 44, and a side heating element 43. The upper heating element 42 is located on the inner top wall of the chamber, the lower heating element 44 is located on the inner bottom wall of the chamber, and the side heating element 43 is located on the inner side wall of the chamber. The projections of the upper heating element 42 and the lower heating element 44 on the horizontal plane are arranged perpendicular to each other to form a grid-like spatial heating field.

[0035] Specifically, the preheating chamber 2 is a sealed space consisting of a cover and a main body, within which the workpiece is heated by vapor-liquid vapor. Heating elements are installed on the top, bottom, and side walls inside the chamber, forming three heating assemblies: an upper heating element 42, a lower heating element 44, and side heating elements 43. The upper heating element 42 is fixedly installed below the top wall inside the chamber, near the inner surface of the cover; the lower heating element 44 is fixedly installed above the bottom wall inside the chamber, near the bottom; and the side heating elements 43 are installed on the inner surfaces of the left and right side walls or the front and rear end walls inside the chamber. These heating elements can be in the form of heating wires or heating rods, generating heat when energized.

[0036] The upper heating element 42 and the lower heating element 44 have a specific spatial arrangement. The upper heating element 42 extends along the length or width of the top wall of the cabin, and the lower heating element 44 also extends along the bottom wall of the cabin, but their projection directions on the horizontal plane are perpendicular to each other. That is, if the upper heating element 42 extends along the front-rear direction of the cabin, the lower heating element 44 extends along the left-right direction, and vice versa. The upper heating element 42 and the lower heating element 44 provide radiant heat from above and below the workpiece, respectively. Since their extension directions are perpendicular and intersecting, they form a grid-like heat radiation distribution in space. The side heating element 43 supplements the heat from the side of the workpiece, compensating for the insufficient top and bottom heating in the edge areas.

[0037] During the preheating and welding processes, liquid vapor phase is quantitatively injected into the bottom of the chamber through the inlet tee 41. The injected liquid medium first contacts the bottom wall area where the lower heating element 44 is located. The lower heating element 44 provides the main heat to heat the liquid medium above its boiling point, causing it to vaporize rapidly. Simultaneously, the upper heating element 42 heats the gas in the space from the top, and the side heating element 43 heats from the side. Together, these three elements form a three-dimensional, uniform temperature field inside the chamber. The liquid medium rapidly and uniformly evaporates in the uniform heating field, forming a saturated vapor phase atmosphere. The vapor fills the entire chamber space and uniformly surrounds all surfaces of the workpiece.

[0038] This embodiment combines heating elements in the upper, lower, and side directions, and constructs a grid-like spatial heating field by projecting the upper heating element 42 and the lower heating element 44 perpendicularly, so that all areas inside the cabin are fully heated, and the liquid medium is uniformly and rapidly converted into saturated steam in a short time.

[0039] The technical benefits achieved by this structure include three aspects. First, it offers high heating efficiency, with the liquid medium rapidly and uniformly vaporizing after injection, shortening the cycle time for preheating and welding. Second, it provides uniform steam concentration distribution, ensuring consistent steam volume and condensation heat release across all workpiece surfaces, resulting in good overall workpiece temperature uniformity. This eliminates the localized hot and cold spots present in contact heating methods, leading to consistent weld quality. Third, the side heating element 43 effectively reduces steam condensation on the inner surface of the chamber wall, maintaining a stable steam concentration within the chamber.

[0040] In a preferred embodiment, a temperature measuring device 6 is provided inside the preheating chamber 2 and / or the welding chamber 4, the temperature measuring device 6 comprising: Temperature measuring bracket 66 is fixedly installed on the inner bottom wall of the cabin; Temperature measuring base 64 is installed on temperature measuring bracket 66; The temperature-sensing contact copper block 61 is movably mounted on the temperature-sensing base 64 via the guide part 63. A high-temperature spring 62 is sleeved on the guide part 63 so that the temperature-sensing contact copper block 61 can elastically float along the axial direction of the guide part 63. A temperature-sensing thermocouple 65 is installed at the bottom of the temperature-sensing contact copper block 61; The temperature-measuring contact copper block 61 has a flat middle section and beveled ends. When the workpiece tray passes by, the beveled ends guide the tray to gradually compress the high-temperature spring 62, eventually making it tightly fit against the flat middle section.

[0041] Specifically, the temperature measuring device 6 is installed on the inner bottom wall of the preheating chamber 2, and is used to perform real-time contact measurement of the temperature of the workpiece pallet and the workpiece during the process of the workpiece pallet entering the chamber and moving along the conveying direction.

[0042] The temperature measuring bracket 66 is the mounting base for the temperature measuring device 6. It is made of sheet metal and is bolted to a predetermined position on the bottom wall of the chamber. The upper part of the temperature measuring bracket 66 has an elongated hole extending vertically to adjust the installation height of the temperature measuring base 64. The temperature measuring base 64 is a block-shaped component, fixed to the temperature measuring bracket 66 by bolts or screws passing through the elongated hole. Because the elongated hole provides vertical adjustment, the temperature measuring base 64 can be moved up and down to a suitable height after loosening the fasteners and then re-locked, thereby adjusting the height of the entire temperature measuring device 6 relative to the workpiece tray feeding plane.

[0043] A vertically oriented guide portion 63 is installed on the temperature measuring base 64. In this embodiment, the guide portion 63 is specifically a temperature measuring block guide screw, the lower end of which is screwed into a threaded hole on the top surface of the temperature measuring base 64 for fixation, and the upper end extends upward. A high-temperature spring 62 is sleeved on the outside of the guide screw, with its lower end supported on the top surface of the temperature measuring base 64 and its upper end being a free end. The temperature measuring contact copper block 61 is a block-shaped metal component with a through hole at its bottom that mates with the guide screw. The temperature measuring contact copper block 61 is sleeved on the guide screw through this through hole and sits on the upper end face of the high-temperature spring 62. Thus, the temperature measuring contact copper block 61 can float up and down along the axial direction of the guide screw, and the high-temperature spring 62 provides it with an upward elastic support force.

[0044] The temperature-sensing contact copper block 61 has specific geometric features. The top surface of the copper block is the working surface that contacts the workpiece tray, and this working surface is divided into three areas: a middle section and two ends. The middle section is a horizontal plane, and each end is machined into a slope, which gradually slopes downwards from the middle section to the ends. The slopes of the two slopes are gentle; in this embodiment, they are trapezoidal slopes with rounded edges. A temperature-sensing thermocouple 65 is installed at the bottom of the temperature-sensing contact copper block 61, and the temperature probe of the thermocouple is tightly fitted into a blind hole or channel on the bottom surface of the copper block, sensing the temperature through thermal conduction.

[0045] During operation, the workpiece pallet enters the preheating chamber 2 horizontally along the conveying direction, with its bottom surface gradually approaching the temperature measuring device 6. The lower front surface of the pallet first contacts the inclined surface at the entrance of the temperature measuring contact copper block 61. As the pallet continues to advance, the inclined surface converts the horizontal movement of the pallet into a vertical compressive force on the copper block. The copper block overcomes the elastic force of the high-temperature spring 62 and gradually moves downward along the guide screw, compressing the spring. When the pallet reaches the middle plane area of ​​the temperature measuring contact copper block 61, the bottom surface of the pallet completely adheres to the middle plane, forming a tight surface contact between the two. At this time, the compression of the spring reaches its maximum, and the spring reaction force acts on the bottom surface of the pallet through the copper block, ensuring a tight, gapless contact. The temperature measured by the thermocouple accurately reflects the true temperature of the pallet and the workpiece.

[0046] The technical problem solved by this temperature measuring device 6 is that in existing online vapor phase welding equipment, the temperature measuring thermocouple 65 usually requires an independent lifting mechanism to drive its ascent to contact the tray and its descent to detach, resulting in a complex structure and the lifting mechanism being prone to failure in high-temperature steam environments. This invention eliminates the lifting mechanism, fixing the temperature measuring device 6 at the bottom of the chamber. The horizontal conveying motion of the tray itself completes the temperature measurement contact action. Through the inclined guidance of the temperature-contacting copper block 61 and the spring-floating adaptive structure, reliable, automated temperature measurement is achieved without power. The technical advantages of this structure are: the temperature measuring device 6 has a simplified structure and high reliability during long-term operation in high-temperature steam and vacuum environments. The spring elastic support and inclined guidance design ensure smooth, impact-free tray movement, tight contact, and high measurement accuracy; when the tray leaves, the spring automatically resets, without affecting subsequent measurements on subsequent trays.

[0047] The inclined angle of the temperature-measuring contact copper block 61, the length of its middle section, and the stiffness of the high-temperature spring 62 are determined as follows: The inclination angle of the inclined plane is determined based on the horizontal conveying speed of the workpiece pallet and the vertical compression stroke required by the temperature measuring contact copper block 61, so that the inclined plane can convert the horizontal movement of the pallet into the vertical compression movement of the temperature measuring contact copper block 61 when the pallet passes by. The length of the middle section plane is determined based on the contact area required for temperature measurement and the available continuous plane length on the bottom of the tray. The stiffness of the high-temperature spring 62 is determined based on the mass of the tray and the inclination angle of the inclined plane, so that the elastic force provided by the spring in the compressed state can be reliably compressed by the tray to the vertical compression stroke, and can also generate a contact pressure between the middle plane and the bottom surface of the tray that meets the temperature measurement accuracy requirements.

[0048] Specifically, the first step is to determine the horizontal conveying speed V of the pallet and the vertical compression stroke H that the copper block needs to complete. The pallet conveying speed V is determined based on the overall production cycle of the equipment and is a known parameter. The vertical compression stroke H is equal to the height of the highest point of the top surface of the temperature-sensing contact copper block 61 in its free state above the pallet's feed plane. This value should be greater than the flatness tolerance of the pallet's bottom surface to ensure that even if there is a lowest point on the pallet's bottom surface, the copper block can still make full contact with the pallet after compression. Generally, two to three times the flatness tolerance is taken as a safety margin.

[0049] The second step involves the inclined planes at both ends of the copper block converting the horizontal motion of the tray into the vertical compression motion of the copper block. The inclination angle θ determines the conversion ratio between the horizontal and vertical forces. If the inclination angle θ is too large, the horizontal component of the force is large, resulting in high resistance to the tray's movement. If the inclination angle θ is too small, the vertical compression generated over the same horizontal distance is small, potentially preventing sufficient contact between the middle section of the copper block and the bottom surface of the tray. Let the projected length of the inclined plane in the horizontal direction be L, and the vertical compression stroke be H. Then, tanθ equals H divided by L. The value of L is limited by the continuous plane length of the tray's bottom surface available for the inclined plane in the direction of travel, which is determined by the structural dimensions of the tray's bottom surface. Therefore, the value of θ is determined to be between eight and fifteen degrees, ensuring a certain vertical compression efficiency while avoiding excessive horizontal resistance.

[0050] The third step is to determine the stiffness K of the high-temperature spring 62. When the tray passes over the copper block, the tray's own weight and the horizontal thrust provided by the conveying mechanism work together through the vertical component of the force converted from the inclined plane, compressing the spring. The spring stiffness K must satisfy two boundary conditions. The lower limit condition is that the spring can be reliably compressed by the tray to a predetermined stroke H, that is, the elastic force F of the spring at the compression stroke H is equal to K multiplied by H, and this elastic force cannot exceed the sum of the tray's weight and the maximum vertical component of the force converted from the inclined plane. The upper limit condition is that the elastic force of the spring in the compressed state can provide sufficient contact pressure to ensure that the contact thermal resistance between the middle section of the copper block and the bottom surface of the tray is sufficiently small to meet the temperature measurement accuracy requirements. The minimum pressure required for contact is calculated based on the heat transfer contact thermal resistance model and is related to the area, surface roughness, and material of the bottom surface of the copper block. The value of the spring stiffness K is selected within the range determined by the lower and upper limit conditions, and the midpoint of the range is taken as the design value, with a margin for adjustment above and below.

[0051] Furthermore, the length of the middle section plane of the temperature-measuring contact copper block 61 and the inclination angle of the inclined plane satisfy the following matching relationship: the length of the middle section plane is such that when the workpiece tray passes by at a preset conveying speed, the contact time with the copper block is greater than or equal to the minimum response time of the temperature-measuring thermocouple 65; the sum of the projected lengths of the inclined sections at both ends in the horizontal direction is equal to the remaining value after subtracting the length of the middle section plane from the total allowable length of the copper block; the inclination angle of the inclined plane is determined by back calculation based on the sum of the projected lengths and the vertical compression stroke.

[0052] The specific steps are as follows: First, calculate the minimum length of the middle section plane based on the thermocouple's response time and transmission speed. This length is equal to the product of the transmission speed and the thermocouple's response time, multiplied by a safety factor. The safety factor is used to cover temperature and response time fluctuations, and is generally taken as 1.2 to 1.5. A certain response time is required for the thermocouple to output a stable temperature reading from contact with the copper block. If the contact time of the tray across the middle section plane is shorter than this response time, the thermocouple will lose contact before reaching a stable reading, resulting in a lower measured temperature. The safety factor is used to cover instantaneous fluctuations in transmission speed, drift in thermocouple response time with temperature changes, and instantaneous poor contact due to equipment vibration. Second, determine the upper limit of the total length of the copper block based on the installation space inside the chamber. Subtract the minimum length of the middle section plane from the upper limit of the total length to obtain the upper limit of the sum of the projected lengths of the two inclined planes. Third, calculate the inclined plane angle based on the vertical compression stroke H and the upper limit of the sum of the projected lengths of the inclined planes. If the calculated angle is within the range of eight to fifteen degrees, the parameters are feasible. If the inverse tilt angle exceeds the range, the safety factor of the mid-section plane length needs to be adjusted, or the value of the compression stroke H needs to be adjusted, and the calculation needs to be iterated again until all parameters meet the boundary conditions.

[0053] Furthermore, the initial stiffness of the high-temperature spring 62 satisfies the following: after the high-temperature spring 62 has undergone its designed life cycle at the operating temperature of the equipment, the elastic force generated by the product of its remaining stiffness and vertical compression stroke is still greater than or equal to the minimum contact pressure required between the middle section plane and the bottom surface of the tray to meet the temperature measurement accuracy.

[0054] Specifically, this method further incorporates a stiffness decay margin consideration between determining the lower and upper limits of spring stiffness. When a spring operates under high temperature and continuous compressive loads for an extended period, the material undergoes stress relaxation. The elastic force generated under the same compression gradually decreases over time, macroscopically equivalent to a decrease in the effective stiffness of the spring. This method incorporates this equivalent stiffness decay into the design considerations. The specific steps are as follows: First, based on the creep or stress relaxation characteristic curve of the spring material at the operating temperature, obtain the expected stiffness decay rate of the spring within the equipment's design life cycle. For example, after several hours of high-temperature service, the stiffness decays to a certain percentage of the initial stiffness. Second, using the actual remaining stiffness of the spring at the end of the equipment's design life cycle as the calculation basis, re-verify whether the contact pressure still meets the temperature measurement accuracy requirements. That is, the elastic force generated by the spring at the compression stroke H is calculated by multiplying the decayed remaining stiffness by H; this value must still be greater than or equal to the lower limit of the contact pressure. Third, if the remaining stiffness does not meet the requirements, increase the initial stiffness value of the spring so that the remaining stiffness at the end of the decay just meets the lower limit condition. The difference between the initial stiffness and the remaining stiffness at the end point is the stiffness decay margin. The essence of this method is to change the spring stiffness design from a single-point design to a range design that considers the entire life cycle. The initial stiffness no longer only meets the requirements of the newly installed state, but is determined by extrapolating upwards based on meeting the requirements of the decay end state.

[0055] In a preferred embodiment, the lifting drive assembly 33 includes a lifting sub-plate having at least two flange ends, each flange end having a chuck seat 35 fixed thereon; the lower end of each support rod 32 passes through a chuck seat 35 and is detachably fastened by a nut; each chuck seat 35 has a threaded hole at its bottom end, and a leveling screw 36 is screwed into the threaded hole from bottom to top, with the top end of the leveling screw 36 abutting against the lower end face of the corresponding support rod 32.

[0056] Specifically, the lifting drive assembly 33 includes a lifting sub-plate, which is horizontally positioned in the space below the bottom wall of the reduction chamber 3. The lifting sub-plate has a plate-like structure, with its main body fixedly connected to the lead screw nut of the ball screw pair. It receives rotational power from the servo motor and reducer, converting the rotation of the lead screw into its own vertical linear motion. The lifting sub-plate has at least two flange ends, which are cantilevered protrusions extending outward from the main body of the lifting sub-plate. These flange ends are arranged opposite each other on both sides of the lifting sub-plate, making the entire lifting sub-plate symmetrically arranged. The significance of the symmetrical arrangement is to ensure that the supporting force of the strut 32 is evenly distributed on both sides of the lifting sub-plate, avoiding tilting of the lifting sub-plate due to uneven loading, which would affect the levelness of the heating plate 31.

[0057] A chuck seat 35 is fixedly installed on each flange end. The chuck seat 35 is a connecting component used to clamp and secure the lower end of the support rod 32. Its body is fixed to the upper surface or side of the flange end by welding or bolting. The chuck seat 35 has a vertically penetrating through hole inside, the inner diameter of which matches the outer diameter of the lower end of the support rod 32. The lower end of each support rod 32 passes through a corresponding through hole in the chuck seat 35 from top to bottom, and continues to extend downward for a certain length after passing through the chuck seat 35. To achieve reliable fixation between the support rod 32 and the chuck seat 35, the portion of the lower end of the support rod 32 that passes through the chuck seat 35 is machined with external threads. A nut is screwed into the external threaded section of the lower end of the support rod 32 from below to lock the support rod 32 into the chuck seat 35. The threaded connection between the nut and the bottom surface of the chuck seat 35 is a detachable fastening method. After loosening the nut, the support rod 32 can slide along the axial direction of the through hole to change the support height. After tightening the nut, the support rod 32 is firmly locked.

[0058] Each chuck 35 has a threaded hole at its bottom end. The axis of the threaded hole is vertical, extending upward from the bottom surface of the chuck 35 and communicating with the through hole. The leveling screw 36 is screwed into the threaded hole from bottom to top, and its insertion depth can be changed by rotating the leveling screw 36. The tip of the leveling screw 36 passes through the threaded hole and extends into the through hole, abutting against the lower end face of the support rod 32 that passes through the through hole. When the nut is in the loose state, rotating the leveling screw 36 pushes it upward, and its tip pushes the lower end face of the support rod 32, which is then lifted upward, and the height of the heating plate 31 at the corresponding position increases accordingly. Reverse rotation of the leveling screw 36 pushes it downward, and the support rod 32 falls back downward under the action of gravity and the weight of the heating plate 31, and the height of the heating plate 31 at the corresponding position decreases accordingly. Once the leveling screws 36 corresponding to each support rod 32 are adjusted to the appropriate position, the overall levelness of the heating plate 31 is up to standard. At this point, tighten the nuts to lock the position of the support rods 32 and complete the leveling operation.

[0059] The technical problem solved by this leveling structure is that when multiple support rods 32 support the same heating plate 31, slight differences in the actual support height of each support rod 32 occur due to machining tolerances and assembly errors. This results in the heating plate 31 not being level after installation, leading to localized suspension or excessive pressure when in contact with the workpiece tray, affecting the uniformity of heat conduction and the reduction process effect. In traditional solutions, the heating plate 31 and support rods 32 are usually fixedly connected. Once installed, if tilting occurs, disassembly and replacement of shims or on-site repair are required, which is cumbersome and difficult to guarantee accuracy. This embodiment separates the leveling and locking functions through the threaded engagement of the leveling screw 36 with the chuck seat 35 and the detachable fastening method of the nut to the support rod 32. The leveling screw 36 is responsible for precisely adjusting the support height, while the nut is responsible for the final locking position. During operation, first loosen the nut, then rotate the leveling screw 36 for fine-tuning of the height, and finally tighten the nut to complete the adjustment. The entire process does not require disassembling the support rods 32 or the heating plate 31. This structure offers high adjustment precision and is easy to operate, making it particularly suitable for applications requiring regular maintenance and precision calibration in online production equipment.

[0060] In a preferred embodiment, the bottom of the preheating chamber 2 and / or the welding chamber 4 is connected to a chamber liquid inlet tee 41. The first end of the chamber liquid inlet tee 41 is connected to an inert gas pipeline through a flow regulating valve, the second end is connected to a vapor-liquid pipeline through an on / off valve, and the third end is connected to the interior of the chamber. The flow regulating valve and the on / off valve are arranged in parallel to realize single injection or mixed injection of vapor-liquid and inert gas.

[0061] Specifically, a liquid inlet tee 41 is provided at the bottom of the preheating chamber 2 and the welding chamber 4. The liquid inlet tee 41 is a three-port pipe joint, with the third end directly connected to the internal space of the chamber. After the medium enters the chamber through the third end, it is distributed at the bottom of the chamber and is heated and vaporized in contact with the area where the lower heating element 44 is located.

[0062] The first end of the tee 41 for liquid inlet in the cabin is connected to an inert gas pipeline via a pipe. A flow regulating valve is connected in series on this connecting pipe. In this embodiment, the flow regulating valve is specifically a miniature electric valve, which can receive control signals to precisely adjust the valve opening, thereby finely controlling the input flow rate of the inert gas. The second end of the tee 41 for liquid inlet in the cabin is connected to a vapor-liquid pipeline via a pipe. A shut-off valve is connected in series on this connecting pipe. In this embodiment, the shut-off valve is specifically a pneumatic electromagnetic angle seat valve, which has two working states: open and closed. When open, the liquid vapor phase can flow into the cabin; when closed, the medium passage is cut off. The first pipeline containing the flow regulating valve and the second pipeline containing the shut-off valve are connected in parallel at the tee 41 for liquid inlet in the cabin, that is, the two pipelines are independently connected to the two inlet ends of the tee, and the two mediums merge in the inner cavity of the tee before entering the cabin.

[0063] This parallel dual-valve structure enables flexible switching between three media injection modes. The first mode is a single vapor-liquid injection mode, where the on / off valve is open, and the flow control valve is closed or kept at a very small opening. The liquid vapor-liquid flows into the chamber through the second pipeline and the third end. The second mode is a single inert gas injection mode, where the on / off valve is closed, the flow control valve is open, and inert gases such as nitrogen are blown into the chamber through the first pipeline and the third end. The third mode is a mixed injection mode, where both the on / off valve and the flow control valve are open simultaneously. The liquid vapor-liquid and inert gas mix in the three-way cavity and then enter the chamber together through the third end, achieving mixed atmosphere injection.

[0064] The technical problem addressed by this structure is that in traditional equipment, the vapor-liquid injection pipeline and the inert gas pipeline are typically connected to the chamber through separate interfaces. The two media mix inside the chamber, resulting in numerous interfaces and increased sealing points, thus increasing the risk of leakage. Furthermore, switching between different media requires controlling two independent interfaces, complicating the operational sequence. This embodiment uses a chamber inlet tee 41 to merge the two media into a single inlet, reducing the number of openings in the chamber wall and lowering the sealing difficulty. Two parallel valves independently control their respective pipelines, providing clear control logic, and the flow regulating valve offers fine-tuning capabilities, enabling precise proportioning of each medium during mixed injection. This structure provides technical flexibility for subsequent process optimization, such as using mixed injection to control the heating rate during the preheating stage and switching to pure vapor-liquid injection during the welding stage to ensure steam purity.

[0065] In a preferred embodiment, the vacuum pipeline includes a main pipeline and branch pipelines connected in parallel; a first pneumatic baffle valve is connected in series on the main pipeline, and a second pneumatic baffle valve and a suction regulating valve are connected in series on the branch pipelines; the main pipeline forms a fast suction path, and the branch pipelines form a slow suction path with adjustable flow rate.

[0066] Specifically, the input ends of both the main pipeline and branch pipelines are connected to the top interfaces of the preheating chamber 2 and the welding chamber 4 via pipes, and their output ends converge and connect to the inlet of the condensation recovery unit. The main pipeline has a larger diameter than the branch pipelines, resulting in lower resistance and a larger pumping flow rate. The branch pipelines have a relatively smaller diameter and are connected in series with adjustable valves, allowing for fine-tuning of the gas flow rate. A first pneumatic baffle valve is connected in series on the main pipeline. This pneumatic baffle valve is an on / off valve driven by compressed air, with both fully open and fully closed states, offering fast response and good sealing. When the first pneumatic baffle valve is open, the main pipeline is unobstructed, and the suction force of the vacuum pump acts on the chamber through the main pipeline, drawing out the gas inside the chamber at a high flow rate and speed, achieving rapid vacuuming. A second pneumatic baffle valve and a pumping regulating valve are connected in series on the branch pipelines, with the two valves sequentially arranged along the airflow direction. The second pneumatic baffle valve is also an on / off valve. The air extraction regulating valve is a flow control valve with adjustable opening. It can adjust the flow cross-sectional area by changing the position of the valve core, thereby adjusting the flow rate of the gas.

[0067] In actual vacuuming operations, the process is divided into two stages. Initially, the internal pressure of the chamber is close to atmospheric pressure. At this point, the first pneumatic baffle valve opens, and the second pneumatic baffle valve closes. The vacuum pump draws gas from the chamber at a high flow rate through the main pipeline, causing the chamber pressure to drop rapidly. The main pipeline forms a fast-vacuum path, which can quickly reduce the chamber pressure to the required rough vacuum range. When the chamber vacuum level approaches the preset switching value, the first pneumatic baffle valve closes, the second pneumatic baffle valve opens, and simultaneously, the pumping regulating valve opens to the preset opening degree. The vacuum pump then switches to a branch pipeline to continue pumping at a lower flow rate and speed. The branch pipeline forms a slow-vacuum path with adjustable flow rate. By adjusting the opening degree of the pumping regulating valve, the pumping rate can be precisely controlled.

[0068] The technical problem this fast and slow extraction dual-path structure aims to solve is that in online vapor phase welding equipment, the workpiece is placed on a tray, which is horizontally placed in the chamber along the conveying direction, without clamping or fixing the workpiece to the tray. If the vacuuming speed is too fast, the airflow thrust generated by the rapid flow of gas in the chamber may push the workpiece to slide and shift on the tray, deviating from the predetermined welding position, and in severe cases, even causing the workpiece to overturn or collide with adjacent workpieces. Especially in welding chamber 4, where the solder is in a molten state, the airflow impact is more likely to cause weld deformation or bridging. However, if slow extraction is used throughout the process, the vacuuming time is too long, affecting the production cycle. This embodiment sets up two parallel extraction paths, fast and slow extraction. In the initial stage of vacuuming, when the chamber pressure is high and the airflow thrust is large, the large-diameter main pipeline is used for fast extraction, making full use of the advantage that fast extraction has less impact on the working time to quickly reduce the pressure; when the pressure drops to a stage where the airflow thrust is no longer a concern, the branch pipeline is switched to slow extraction, precisely controlling the remaining extraction process to avoid disturbing the workpiece, thus taking into account both the process requirements of vacuuming efficiency and workpiece positioning stability.

[0069] In a preferred embodiment, the lifting drive assembly 33 further includes a support beam 34 fixed to the top of the support rod 32, and the heating plate 31 is supported on the support beam 34. The support beam 34 is provided with three positioning pins 37, and the heating plate 31 is provided with three corresponding through holes. The heating plate 31 is fitted onto the positioning pins 37 through the through holes for limiting its position. The middle positioning pin 37 is installed at a higher height than the two positioning pins 37 on both sides, so that after the heating plate 31 is installed, the two sides of the heating plate 31 have height adjustment space relative to the support beam 34.

[0070] Specifically, a crossbeam 34 is fixedly connected to the top of the support rod 32. The crossbeam 34 is a horizontally arranged strip-shaped component, and its bottom surface is fixed to the top of the support rod 32 by welding or bolting. The upper surface of the crossbeam 34 forms a support surface for the heating plate 31, and the heating plate 31 rests entirely on the crossbeam 34, which bears the entire weight of the heating plate 31 and its electric heating element.

[0071] Three locating pins 37 are provided on the upper surface of the strut beam 34, and are spaced apart along the length of the strut beam 34. Each locating pin 37 is a cylindrical pin, its lower end fixed to the strut beam 34 by an interference fit or threaded connection, and its upper end protruding upwards from the upper surface of the strut beam 34. Correspondingly, three through holes are provided on the lower surface of the heating plate 31, and the positions of the three through holes correspond one-to-one with the three locating pins 37. The heating plate 31 is fitted onto the three locating pins 37 through these three through holes, with a clearance fit between the through holes and the locating pins 37. This ensures that the heating plate 31 can be smoothly installed, and also constrains the displacement and rotational freedom of the heating plate 31 in the horizontal plane through the fit between the locating pins 37 and the through holes, thus achieving a limiting function.

[0072] The three locating pins 37 have specific differences in their installation height. The locating pin 37 located in the middle of the strut beam 34 protrudes slightly higher from the upper surface of the strut beam 34; the two locating pins 37 on both sides protrude slightly lower. In this embodiment, the installation height of the middle locating pin 37 is about one millimeter higher than that of the two locating pins 37. When the heating plate 31 is fitted with the three locating pins 37 through the three through holes, the bottom surface of the heating plate 31 first contacts the top stepped surface of the middle locating pin 37, which has the higher height, while there is still a small gap between the through holes on both sides and the stepped surfaces of the two locating pins 37. This gap is the height adjustment space of the heating plate 31 relative to the strut beam 34.

[0073] During the second leveling stage of the leveling operation, the operator uses a wrench to tighten the leveling screw 36 at the bottom of the chuck seat 35, changing the support height of the two side support rods 32. Because the heating plate 31 is supported by the central locating pin 37, there is a gap between the through holes on both sides and the stepped surface of the locating pin 37. When adjusting the height of the two side support rods 32, the heating plate 31 can deflect slightly at the central locating pin 37 as a fulcrum, thus achieving independent height adjustment on both sides. After leveling is completed, the bottom surface of the heating plate 31 is fully in contact with the stepped surfaces of the three locating pins 37, and the heating plate 31 is in a horizontal state. If the three locating pins 37 are at the same height, the bottom surface of the heating plate 31 will be fully in contact with the three locating pins 37 after installation, completely eliminating the height adjustment range, and the leveling operation cannot be performed.

[0074] The technical problem solved by this three-point unequal-height positioning pin 37 structure lies in the functional contradiction between positioning and leveling. The positioning pins 37 are required to constrain the position of the heating plate 31, reducing its degrees of freedom; the leveling operation requires the heating plate 31 to still have a certain amount of space for posture adjustment after installation. If all positioning pins 37 are of equal height, the heating plate 31 is completely limited after being fitted in, and its levelness cannot be changed by adjusting the height of the support rod 32. If the positioning pins 37 are completely eliminated and the heating plate 31 rests on the support rod beam 34 solely by its own weight, the heating plate 31 will not be reliably positioned in the horizontal plane and may gradually shift during equipment vibration, affecting its accurate fit with the workpiece tray. This embodiment uses a differentiated height design with three positioning pins 37, one higher in the middle and one lower on both sides, to reliably support and position the heating plate 31 in the middle after installation, while leaving gaps on both sides to provide adjustment freedom. This not only uses the positioning pins 37 to limit the horizontal displacement of the heating plate 31 and prevent it from falling off, but also reserves the necessary space for leveling operations, resolving the contradiction between positioning and leveling in terms of assembly accuracy requirements. The structure is ingeniously designed with few parts and no additional leveling accessories. It achieves complex functions by simply varying the height of the locating pin 37.

[0075] In a preferred embodiment, the temperature measuring bracket 66 has an elongated hole, the length of which extends vertically; the temperature measuring base 64 is height-adjustably mounted on the temperature measuring bracket 66 by fasteners passing through the elongated hole, so as to adjust the height of the temperature measuring contact copper block 61 relative to the workpiece tray feeding plane.

[0076] Specifically, the temperature measuring bracket 66 is fixedly installed on the bottom wall of the chamber. An elongated hole is formed on the upright plate of the bracket, extending vertically. The temperature measuring base 64 is installed on the temperature measuring bracket 66 via fasteners passing through the elongated hole. Bolts or screws can be used as fasteners. After loosening the fasteners, the temperature measuring base 64 can be moved up and down along the elongated hole to adjust the height of the temperature-measuring contact copper block 61 relative to the workpiece tray's feed plane. After adjusting to the appropriate position, the fasteners are tightened. This elongated hole adjustment structure allows the temperature measuring device 6 to adapt to trays of different thicknesses or different process height requirements, achieving height adjustment without replacing parts.

[0077] In a preferred embodiment, a heat-insulating protective cover for the hatch is provided above the upper heating element 42. The heat-insulating protective cover for the hatch covers the outer surface of the hatch cover of the preheating chamber 2 and / or welding chamber 4, and is detachably fastened to the hatch cover by a plucked handle.

[0078] A heat-insulating protective cover is installed above the upper heating element 42, covering the outer surface of the hatch cover of the preheating chamber 2 or welding chamber 4. The main function of the heat-insulating protective cover is to reduce the heat radiation loss of the upper heating element 42 to the external environment, and at the same time lower the temperature of the outer surface of the hatch cover to ensure operational safety. The protective cover is detachably fastened to the hatch cover by a Phillips-shaped handle, which is a manual screw-on fastener that can be installed and removed without tools, facilitating quick installation and removal of the protective cover during routine inspection and maintenance.

[0079] Furthermore, a fumigation device 7 is provided at the inlet and outlet to capture the vapor phase liquid vapor escaping from the hatch when the gate valve is opened for workpiece feeding or discharging.

[0080] Specifically, the fumigation device 7 includes a fumigation hood, an exhaust fan, and a collection bottle. The fumigation hood is installed above the valves at the inlet and outlet, with its opening facing the valve opening area, to create a negative pressure collection zone outside the hatch after the valve is opened. The outlet of the fumigation hood is connected to the inlet of the exhaust fan via a pipe, and the outlet of the exhaust fan is connected to the collection bottle via a pipe. The collection bottle contains a filter assembly, such as a precision filter screen or filter element, and has a drain valve at the bottom of the bottle.

[0081] During equipment operation, whenever the valves of preheating chamber 2 or welding chamber 4 are opened to load or unload workpiece pallets, some vapor phase liquid vapor inside the chamber will escape to the outside. At this time, the exhaust fan starts simultaneously, drawing the overflowing vapor phase liquid vapor along with the surrounding air through the fume hood and transporting it along the pipeline to the collection bottle. The vapor cools and condenses into a liquid medium in the collection bottle, which is then filtered by the filter assembly to remove any impurities and temporarily stored in the bottle. Operators can periodically open the drain valve to pour the collected and filtered liquid vapor phase liquid into the storage tank, allowing it to re-enter the closed-loop circulation pipeline system for reuse. This fume extraction device 7 solves the problem of vapor phase liquid loss caused by frequent chamber openings, further reducing media consumption and improving the working environment around the equipment.

[0082] Furthermore, the vapor-liquid closed-loop circulation pipeline system also includes a filter device located at the exhaust port of the vacuum pump, which is used to perform secondary recovery of the trace amount of vapor-liquid vapor that is still discharged with the airflow after passing through the condensation recovery device.

[0083] Specifically, the filtration device includes a filter tank filled with Pall ring packing to form a gas-liquid contact bed with a large specific surface area. The filter tank has an inlet and an outlet; the inlet is sealed to the exhaust port of a vacuum pump via a pipe, while the outlet is open to the atmosphere or connected to a post-treatment pipeline. The Pall rings can be multifaceted hollow spherical structures made of metal or corrosion-resistant plastic to increase the effective contact area between the airflow and the packing surface.

[0084] During the actual vacuuming process, the vapor phase liquid vapor extracted from preheating chamber 2 and welding chamber 4 first enters the condensation recovery device through the vacuum pipeline. Most of the vapor is condensed into a liquid medium and recovered to the storage tank. However, due to limitations in condensation efficiency and gas flow rate, a small amount of vapor phase liquid vapor may still pass through the condensation recovery device in gaseous or mist form, enter the vacuum pump with the carrier gas, and be discharged from the exhaust port. This gas flow containing trace amounts of medium enters the filter tank and meanders through the Pall ring packing layer. The vapor and mist continuously collide, coalesce, and condense on the packing surface to form a liquid medium, which gathers at the bottom of the filter tank. A drain port is provided at the bottom of the tank, which can periodically discharge the collected liquid vapor phase liquid into the storage tank, thereby improving the overall recovery rate of vapor phase liquid to a higher level. This filter device, through the high-efficiency adsorption area provided by the Pall ring packing, achieves deep recovery of residual vapor phase liquid vapor in the pipeline exhaust gas. Working in synergy with the condensation recovery device, it reduces media loss to a lower level and is simple in structure and easy to maintain.

[0085] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An online vapor phase welding device for vapor-liquid recycling, characterized in that, include: The preheating chamber (2), reduction chamber (3), welding chamber (4) and cooling chamber (5) are arranged sequentially along the workpiece conveying direction; Also includes: Vapor-liquid closed-loop circulation piping system: including vacuum piping, condensation recovery device, liquid storage tank and circulation pump; The input end of the vacuum pipeline is connected to the preheating chamber (2) and the welding chamber (4) respectively, and its output end is connected to the inlet of the condensation recovery device, which is used to draw the uncondensed vapor phase liquid vapor in the preheating chamber (2) and the welding chamber (4) to the condensation recovery device. The condensation recovery device is used to condense vapor phase liquid vapor into liquid medium, and its outlet is connected to the storage tank; The outlet of the storage tank is connected to the inlet of the preheating chamber (2) and the welding chamber (4) through the circulation pump, so as to pump the recovered liquid medium back into the chamber to form a closed-loop recycling of vapor phase liquid. The preheating chamber (2) and / or the welding chamber (4) are equipped with a temperature measuring device (6), the temperature measuring device (6) comprising: Temperature measuring bracket (66) is fixedly installed on the inner bottom wall of the cabin; Temperature measuring base (64) is installed on the temperature measuring bracket (66); The temperature-measuring contact copper block (61) is movably mounted on the temperature-measuring base (64) via the guide part (63). A high-temperature spring (62) is sleeved on the guide part (63) so that the temperature-measuring contact copper block (61) can elastically float along the axial direction of the guide part (63). A temperature-measuring thermocouple (65) is installed at the bottom of the temperature-measuring contact copper block (61); The temperature-measuring contact copper block (61) has a flat middle section and inclined ends, so that when the workpiece tray passes by, the inclined ends guide the tray to gradually compress the high-temperature spring (62) and finally fit tightly against the middle flat section. The inclined angle of the temperature-measuring contact copper block (61) is determined according to the horizontal conveying speed of the workpiece tray and the vertical compression stroke required by the temperature-measuring contact copper block (61). The length of the middle flat section ensures that the contact time between the workpiece tray and the copper block when the workpiece tray passes by at a preset conveying speed is greater than or equal to the minimum response time of the temperature-measuring thermocouple (65). The initial stiffness of the high temperature spring (62) satisfies the following: after the high temperature spring (62) has undergone its design life cycle at the operating temperature of the equipment, the elastic force generated by the product of its remaining stiffness and vertical compression stroke is still greater than or equal to the minimum contact pressure required between the middle section plane and the bottom surface of the tray to meet the temperature measurement accuracy. The reduction chamber (3) is equipped with a heating plate (31) inside. At least one support rod (32) is fixedly connected to the bottom surface of the heating plate (31). The support rod (32) passes through the bottom wall of the reduction chamber (3) in a sealed manner and is connected to a lifting drive assembly (33) located outside the reduction chamber (3). The lifting drive assembly (33) drives the heating plate (31) to move up and down between a low position and a high position through the support rod (32). When the heating plate (31) is in the high position, its upper surface contacts the workpiece tray that enters the reduction chamber (3).

2. The online vapor phase welding equipment for vapor-liquid recycling according to claim 1, characterized in that, The preheating chamber (2) and the welding chamber (4) are each equipped with an upper heating element (42), a lower heating element (44) and a side heating element (43). The upper heating element (42) is located on the inner top wall of the chamber, the lower heating element (44) is located on the inner bottom wall of the chamber, and the side heating element (43) is located on the inner side wall of the chamber. The projections of the upper heating element (42) and the lower heating element (44) on the horizontal plane are arranged perpendicular to each other to form a grid-like spatial heating field.

3. The online vapor phase welding equipment for vapor-liquid recycling according to claim 1, characterized in that, The lifting drive assembly (33) includes a lifting sub-plate, which has at least two flange ends, and a chuck seat (35) is fixed on each flange end; the lower end of each support rod (32) passes through a chuck seat (35) and is detachably fastened by a nut; each chuck seat (35) has a threaded hole at its bottom end, and a leveling screw (36) is screwed into the threaded hole from bottom to top, and the top end of the leveling screw (36) abuts against the lower end face of the corresponding support rod (32).

4. The online vapor phase welding equipment for vapor-liquid recycling according to claim 1, characterized in that, The bottom of the preheating chamber (2) and / or the welding chamber (4) is connected to a chamber liquid inlet tee (41). The first end of the chamber liquid inlet tee (41) is connected to the inert gas pipeline through a flow regulating valve, the second end is connected to the vapor phase liquid pipeline through an on / off valve, and the third end is connected to the interior of the chamber. The flow regulating valve and the on / off valve are arranged in parallel to realize the single injection or mixed injection of vapor phase liquid and inert gas.

5. The online vapor phase welding equipment for vapor-liquid recycling according to claim 1, characterized in that, The vacuum pipeline includes a main pipeline and branch pipelines connected in parallel; a first pneumatic baffle valve is connected in series on the main pipeline, and a second pneumatic baffle valve and a suction regulating valve are connected in series on the branch pipelines; the main pipeline forms a fast suction path, and the branch pipelines form a slow suction path with adjustable flow rate.

6. The online vapor phase welding equipment for vapor-liquid recycling according to claim 3, characterized in that, The lifting drive assembly (33) also includes a strut beam (34) fixed to the top of the strut (32), and the heating plate (31) is supported on the strut beam (34). The strut beam (34) is provided with three positioning pins (37), and the heating plate (31) is provided with three through holes. The heating plate (31) is fitted onto the positioning pins (37) through the through holes for limiting. The middle positioning pin (37) of the three positioning pins (37) is installed at a higher height than the positioning pins (37) on both sides, so that after the heating plate (31) is installed, the two sides of the heating plate (31) have height adjustment space relative to the strut beam (34).

7. The online vapor phase welding equipment for vapor-liquid recycling according to claim 1, characterized in that, The temperature measuring bracket (66) has an elongated hole, the length of which extends vertically. The temperature measuring base (64) is mounted on the temperature measuring bracket (66) with adjustable height by fasteners inserted into the elongated hole, so as to adjust the height of the temperature measuring contact copper block (61) relative to the workpiece tray feeding plane.

8. The online vapor phase welding equipment for vapor-liquid recycling according to claim 2, characterized in that, A heat-insulating protective cover is provided above the upper heating element (42). The heat-insulating protective cover covers the outer surface of the cover of the preheating chamber (2) and / or welding chamber (4) and is detachably fastened to the cover by a plum blossom handle.

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