A field reflector system
By introducing a field-type reflector system into a continuous vacuum brazing furnace and dynamically adjusting the reflector's orientation, the problem of temperature non-uniformity was solved, heating efficiency and energy efficiency ratio were improved, and more efficient production was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING WEITU VACUUM TECH CO LTD
- Filing Date
- 2026-06-24
- Publication Date
- 2026-07-21
Smart Images
Figure CN122425287A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of vacuum brazing equipment, and more particularly to a field reflector system that can be applied to continuous vacuum brazing furnaces. Background Technology
[0002] Vacuum brazing equipment, with its strong adaptability to various operating conditions, is widely used in high-end manufacturing fields such as automotive, aerospace, and new energy. With the increasing demand for high-volume, high-efficiency industrial production, the industry has developed continuous vacuum brazing furnaces based on traditional intermittent furnaces. These furnaces allow for continuous entry and exit of workpieces into and out of the furnace chamber, and continuous heating and brazing. They offer advantages such as high production efficiency, excellent consistency of brazed products, low energy consumption, and a clean and environmentally friendly production environment, making them suitable for continuous production processes with high-volume, high-welding-quality requirements. Temperature uniformity within the furnace chamber is a core performance parameter of continuous vacuum brazing furnaces, directly determining the brazing quality uniformity, product yield, and process reproducibility of the produced workpieces. In most continuous vacuum brazing furnaces currently on the market, the effective working area of the heating chamber along the material rack's travel direction is relatively large. To control the temperature distribution within the large-volume furnace chamber, the heating system generally adopts a multi-temperature zone independent temperature control structure. However, during actual operation, thermal coupling and mutual interference exist between different temperature zones. Simultaneously, the heating elements exhibit thermal inertia, leading to a significant lag in temperature regulation. This inevitably results in localized high-temperature and low-temperature zones within the furnace working area. To ensure that workpieces in the low-temperature zone meet brazing process requirements, current production methods can only increase the output power of the heating power supply and extend the heat preservation time, thereby reducing the energy utilization rate of the vacuum brazing process and decreasing the processing efficiency of the production line. Summary of the Invention
[0003] To address the aforementioned problems, this invention proposes a field-type reflective screen system to improve heating efficiency in vacuum brazing production.
[0004] This field-type reflective screen system includes a control center and multiple reflective screen units. The reflective screen units are located within the heating chamber of the continuous vacuum brazing furnace, arranged on both sides of the material rack's travel path, forming a row on each side, constituting the first reflective screen sequence. The control center is located outside the heating chamber. Each reflective screen unit includes a reflective screen, a rotating shaft, and a drive unit. The reflective screen is mounted on the rotating shaft, and the reflective surface of the screen is symmetrical about the axis of the rotating shaft; the lower end of the rotating shaft is mounted on the bottom plate of the heating chamber. The drive unit includes a drive motor and a drive control unit; the drive motor is located at one end of the rotating shaft and is used to drive the rotating shaft to rotate at any angle, thereby adjusting the working posture of the reflective screen. The drive control unit receives control commands from the control center and controls the output rotation angle of the drive motor according to the control commands. The control center sends independent control commands to each reflective screen unit in real time. Each reflective screen in each unit performs independent dynamic real-time working posture adjustments according to the control commands and performs field-type thermal reflection work in the adjusted target working posture. A second reflective screen sequence is also provided outside the first reflective screen sequence. The second reflective screen sequence includes multiple fixed reflective screens to reduce heat loss inside the heating chamber.
[0005] In one possible implementation, the rack has a reference area surface, the length and width of which are aligned with the length and height of the rack, respectively; the reference area surface has a center line perpendicular to the travel path, and the reference area surface is axially symmetrical about the center line; when the rack travels within the heating chamber, at any moment during the operation of the field-type reflective screen system, each reflective screen in the target working posture at that moment satisfies the following: the projection of the center line of the area surface closest to the reflective screen onto the reflective screen falls on the axis of the reflective screen's rotation.
[0006] In one possible implementation, the number of reference regions is 2-10, and there is no intersection between different reference regions.
[0007] In one possible implementation, multiple position sensors are installed along the travel path. The position sensors send the position information of the rack on the travel path to the control center in real time. The control center has preset rack parameters including rack shape information and reference area surface information. Based on the position information sent by each position sensor and combined with the rack parameters, the control center derives the control command for each reflector unit and sends the control command to each reflector unit.
[0008] In one possible implementation, temperature measuring devices are installed at multiple temperature measuring points along the travel path; the number of temperature measuring devices is greater than the number of reflector units. Each temperature measuring device sends the temperature signal of its measuring point to the control center in real time. The control center forms temperature field information within the heating chamber based on the temperature signals from each measuring point, performs comprehensive analysis based on this temperature field information, derives control commands for each reflector unit, and sends these control commands to each reflector unit.
[0009] In one possible implementation, the number of temperature measuring devices is not less than 3n.
[0010] In one possible implementation, each reflector in the target working posture satisfies the following: the normal of the reflector surface is oriented to varying degrees toward the temperature field trough that is closer to the reflector.
[0011] In one possible implementation, the degree to which the normal of the reflective surface of the reflective screen in the target working posture is oriented toward a nearby temperature field trough is correlated with the gradient of the temperature signal of the adjacent temperature measuring point directly opposite the reflective screen unit in the direction toward the temperature field trough.
[0012] In one possible implementation, when a reflector is in the target working posture, the angle θi between the normal of the reflector surface and the plane passing through the axis of rotation of the reflector and the temperature measuring point located at the nearest temperature field trough satisfies the following relationship: cosθi=C0+C1·∣Gi|-C2·di.
[0013] C0, C1, and C2 are calibration coefficients related to the structural dimensions of the heating chamber and the reflectivity of the reflective surface. i is the number of the reflector. Gi is the comprehensive temperature gradient, used to characterize the overall cooling gradient trend of the three adjacent temperature measuring points directly opposite the reflector unit along the direction towards the temperature field trough. di is the straight-line distance from the axis of rotation of the reflector to the center of the nearest temperature field trough. Wherein, Gi = ((Ti2-Ti1) / (x2-x1) + (Ti3-Ti2) / (x3-x2)) / 2. x1, x2, and x3 are the position coordinates of the three adjacent temperature measuring points directly opposite the reflector unit along the material rack's travel direction. Ti3, Ti2, and Ti1 are the real-time temperature signals corresponding to these three temperature measuring points.
[0014] The applicant discovered that in existing continuous vacuum brazing furnaces employing multi-zone independent temperature control heating, the factory temperature uniformity test results under empty furnace conditions are acceptable. However, during actual use under full load conditions, the coupling of heat conduction and radiation between different temperature zones makes it difficult to decouple the coupled thermal interference between the multiple temperature zones. This leads to large fluctuations in the overall temperature field and slow temperature field control response. Furthermore, localized temperature deviations (too low or too high) are prone to occur at the boundaries between temperature zones. When conducting densely distributed multi-point temperature measurements of the working area, it was found that this temperature unevenness can reach ±10℃ or more in severe cases. Moreover, due to the monotonicity of the control, multi-zone independent temperature control technology alone cannot completely solve this problem.
[0015] The beneficial effects of this invention are: This invention utilizes a field-type reflective screen system to redistribute existing heat within the heating chamber, creating a reflective heat field that can be dynamically adjusted in real time based on the movement position of the material rack and / or the temperature field distribution within the working area. This reflective heat field, combined with multi-zone temperature control heating methods, compensates for the inherent monotony of multi-zone temperature control heating methods alone through the coupling and superposition of the reflective heat field and the heater's heating heat field. It eliminates the localized high or low temperature phenomena present in existing vacuum brazing furnaces with large working areas, improves the temperature field control response speed, and enhances heating efficiency and energy efficiency ratio.
[0016] The applicant conducted densely distributed multi-point temperature measurements on the heating chamber of a continuous vacuum brazing furnace using the field-type reflective screen system of this invention under operating conditions. The results showed that the temperature control response speed within the working area was improved by more than 50%, temperature uniformity reached within ±1℃, and there were no significant localized high or low temperatures within the temperature zone. With such excellent temperature control, the temperature control margin set in existing technologies to accommodate localized low temperatures can be reduced or even eliminated, and the extended holding time required to mitigate localized temperature dips can be shortened. Experimental tests show that this invention improves the energy efficiency ratio of the continuous vacuum brazing furnace by more than 30%, significantly reducing daily operating costs and improving production efficiency. Attached Figure Description
[0017] Elements with the same reference numerals in the accompanying drawings are shown as similar elements, and the drawings are not intended to be scaled. Wherein: Figure 1 This is a top view of a field-type reflective screen system provided in an embodiment of this application.
[0018] Figure 2 This is a top view diagram provided in an embodiment of this application when the material rack enters the heating chamber.
[0019] Figure 3This is a schematic diagram of the structure of a reflective screen unit provided in an embodiment of this application.
[0020] Figure label: 10. Feeding room; 20, Heating chamber; 201, Heater; 202, Reflector unit; 2021, Reflector; 2022, Rotating shaft; 2023, Drive motor; 2024, Drive control unit; 2025, Axis; 203, Fixed reflector; 30. Cooling chamber; 40. Material rack; 50, Control Center; 60, Isolation valve. Detailed Implementation
[0021] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.
[0022] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of the invention described herein.
[0023] In this invention, the terms "upper," "lower," "inner," "middle," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this invention and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation. Furthermore, some of the aforementioned terms may be used to indicate other meanings besides orientation or positional relationship; for example, the term "upper" may in some cases indicate a certain dependency or connection relationship.
[0024] like Figure 1 , Figure 2 and Figure 3As shown, this application embodiment provides a field reflector system. The field reflector system includes a control center 50 and multiple reflector units 202. The reflector units 202 are disposed within the heating chamber 20 of a continuous vacuum brazing furnace, arranged on both sides of the material rack 40's travel path, forming a row on each side, constituting a first reflector sequence. The control center 50 is located outside the heating chamber 20. Each reflector unit 202 includes a reflector 2021, a rotating shaft 2022, and a drive device. The reflector 2021 is mounted on the rotating shaft 2022, and the reflective surface of the reflector 2021 is symmetrical about the axis 2025 of the rotating shaft 2022. The lower end of the rotating shaft 2022 is mounted on the bottom plate of the heating chamber 20. The drive device includes a drive motor 2023 and a drive control unit 2024. The drive motor 2023 is disposed at one end of the rotating shaft 2022 and is used to drive the rotating shaft 2022 to rotate at any angle, thereby causing the reflector 2021 to adjust its working posture. The drive control unit 2024 receives control commands from the control center 50 and controls the output rotation angle of the drive motor 2023 according to the control commands. The control center 50 sends independent control commands to each reflector unit 202 in real time. The reflector 2021 in each reflector unit 202 makes independent dynamic real-time working posture adjustments according to the control commands and performs field-type heat reflection work in the adjusted target working posture. A second reflector sequence is also arranged outside the first reflector sequence. The second reflector sequence includes multiple fixed reflectors 203. The fixed reflectors 203 are staggered with the reflector units 202 in the first reflector sequence to reduce heat loss in the heating chamber 20.
[0025] In one implementation, such as Figure 1 and Figure 2 As shown, the continuous vacuum brazing furnace also includes a feeding chamber 10 and a cooling chamber 30. The feeding chamber 10, heating chamber 20, and cooling chamber 30 are sequentially connected. The workpiece-loaded rack 40 undergoes a preheating process in the feeding chamber 20. After preheating, the rack 40 enters the heating chamber 20 for vacuum brazing. The heating chamber 20 operates in a vacuum environment isolated from the atmosphere. After vacuum brazing, the rack 40 enters the cooling chamber 30 for cooling.
[0026] In one implementation, such as Figure 1 and Figure 2 As shown, isolation valves 60 are provided between the feeding chamber 10 and the heating chamber 20, as well as between the heating chamber 20 and the cooling chamber 30.
[0027] In one implementation, such as Figure 1 and Figure 2 As shown, a heating system is also installed inside the heating chamber 20. The heating system includes a heater 201. The heating system heats the workpieces on the material rack 40 using a multi-zone temperature control method.
[0028] Figure 1 Specifically, this is a schematic diagram of a continuous vacuum brazing furnace before the material rack enters the heating chamber. Figure 2 Specifically, this is a schematic diagram of a continuous vacuum brazing furnace when the material rack has entered the heating chamber.
[0029] In one implementation, the number of reflective screen units is 2n.
[0030] In one implementation, the rack has a reference area surface, the length and width of which are aligned with the length and height of the rack, respectively. The reference area surface has a centerline perpendicular to the travel path, and the reference area surface is axially symmetrical about this centerline. When the rack moves within the heating chamber, at any given moment during the operation of the field-type reflective screen system, each reflective screen in its target working posture satisfies the following condition: the projection of the centerline of the area surface closest to that reflective screen onto the reflective screen falls on the axis of rotation of that reflective screen.
[0031] In one implementation, the number of reference regions is 2-10, and there is no intersection between different reference regions.
[0032] In one implementation, multiple position sensors are installed along the travel path, transmitting the position information of the material rack along the travel path to the control center in real time. The control center has pre-set material rack parameters, including the rack's shape information and reference area surface information. Based on the position information transmitted by each position sensor and the material rack parameters, the control center derives control commands for each reflector unit and sends these commands to each reflector unit.
[0033] In one implementation, temperature measuring devices are installed at multiple temperature measuring points along the travel path. The number of temperature measuring devices is greater than the number of reflector units. Each temperature measuring device sends the temperature signal of its measuring point to the control center in real time. The control center generates temperature field information within the heating chamber based on the temperature signals from each measuring point, performs comprehensive analysis based on this temperature field information, derives control commands for each reflector unit, and sends these control commands to each reflector unit.
[0034] In one implementation, the number of temperature measuring devices is not less than 3n.
[0035] In one implementation, each reflector in the target working posture satisfies the following condition: the normal of the reflector surface is oriented to varying degrees toward the temperature field trough that is closer to the reflector.
[0036] In one implementation, the degree to which the normal of the reflective surface of the reflective screen in the target working posture is oriented toward a nearby temperature field trough is correlated with the gradient of the temperature signal of the adjacent temperature measuring point directly opposite the reflective screen unit in the direction toward the temperature field trough.
[0037] In one implementation, when a reflector is in the target working posture, the angle θi between the normal of the reflector surface and the plane passing through the axis of rotation of the reflector and the temperature measuring point located at the nearest temperature field trough satisfies the following relationship: cosθi=C0+C1·∣Gi|-C2·di.
[0038] C0, C1, and C2 are calibration coefficients related to the structural dimensions of the heating chamber and the reflectivity of the reflective surface. i is the number of the reflector. Gi is the comprehensive temperature gradient, used to characterize the overall cooling gradient trend of the three adjacent temperature measuring points directly opposite the reflector unit along the direction towards the temperature field trough. di is the straight-line distance from the axis of rotation of the reflector to the center of the nearest temperature field trough. Wherein, Gi = ((Ti2-Ti1) / (x2-x1) + (Ti3-Ti2) / (x3-x2)) / 2. x1, x2, and x3 are the position coordinates of the three adjacent temperature measuring points directly opposite the reflector unit along the material rack's travel direction. Ti3, Ti2, and Ti1 are the real-time temperature signals corresponding to these three temperature measuring points.
[0039] In this embodiment of the application, in the scenario of dynamic temperature field changes in the heating chamber during the actual operation of the continuous vacuum brazing furnace, the control center can obtain the comprehensive temperature gradient Gi and the straight-line distance di from the axis of rotation of the reflector to the nearest temperature field trough center through the real-time temperature signal collected by the temperature measuring device. From this, the target attitude parameter θi of the reflector unit numbered i is obtained, and then the control command is sent to the drive control unit to drive the reflector to adjust to the target working attitude, realize the dynamic adaptation of heat reflection, and ensure the uniformity of the temperature field in the heating chamber.
[0040] In one implementation, C0, C1, and C2 are calibrated through debugging experiments of the heating chamber of a continuous vacuum brazing furnace. C0 ∈ (0, 1], C1 > 0, C2 > 0.
[0041] In one implementation, Ti3, Ti2, and Ti1 are represented by the unit K.
[0042] In one implementation, x1, x2, and x3 are in units of m, and x1 < x2 < x3.
[0043] In one implementation, the distance between two adjacent temperature measuring devices remains constant, i.e., x2-x1=x3-x2.
[0044] In one implementation, the unit of di is m.
[0045] In one implementation, θi∈[0, π / 2]. The smaller θi is, the stronger the orientation of the reflective surface normal towards the temperature field trough; the larger θi is, the weaker the orientation of the reflective surface normal towards the temperature field trough.
[0046] In one implementation, Gi is measured in K / m, and the larger the absolute value of |Gi|, the steeper the cooling trend along the direction towards the trough of the temperature field.
[0047] In one implementation, a purging device is also provided at both ends of the reflective screen; the purging device can purge the reflective surface of the reflective screen. The purging function of the purging device in this invention is closely integrated with the overall function of the field reflective screen system, which can keep the reflectivity of the reflective surface stable, thereby ensuring that the field reflective screen system can efficiently and dynamically adjust the temperature field and improve the response speed of the temperature field to this dynamic adjustment.
Claims
1. A field-type reflective screen system, characterized in that, include: The system comprises a control center and multiple reflector units. These reflector units are located within the heating chamber of the continuous vacuum brazing furnace, arranged on both sides of the material rack's travel path, forming a row on each side to constitute the first reflector sequence. Each reflector unit includes a reflector, a rotating shaft, and a drive unit. The reflector is mounted on the rotating shaft, and its reflective surface is symmetrical about the axis of the rotating shaft. The lower end of the rotating shaft is mounted on the bottom plate of the heating chamber. The drive unit includes a drive motor and a drive control unit. The drive motor is located at one end of the rotating shaft and is used to drive the shaft to rotate at any angle, thereby adjusting the working posture of the reflector. The drive control unit receives control commands from the control center and controls the output rotation angle of the drive motor according to the commands. The control center sends independent control commands to each reflector unit in real time. Each reflector unit performs independent dynamic real-time working posture adjustments according to the control commands and performs field-type heat reflection work in the adjusted target working posture. A second reflector sequence is also located outside the first reflector sequence. The second reflector sequence includes multiple fixed reflectors to reduce heat loss within the heating chamber.
2. The field-type reflective screen system according to claim 1, characterized in that, The material rack has a reference area surface, the length and width of which are aligned with the length and height of the material rack, respectively; the reference area surface has a center line perpendicular to the travel path, and the reference area surface is symmetrical about the center line; when the material rack travels in the heating chamber, at any moment during the operation of the field-type reflective screen system, each reflective screen in the target working posture at that moment satisfies the following: the projection of the center line of the area surface closest to the reflective screen onto the reflective screen falls on the axis of the reflective screen's rotation.
3. The field-type reflective screen system according to claim 2, characterized in that, The number of reference regions is 2-10, and there is no intersection between different reference regions.
4. The field-type reflective screen system according to claim 2, characterized in that, Multiple position sensors are installed along the travel path. The position sensors send the position information of the material rack on the travel path to the control center in real time. The control center has preset material rack parameters, including material rack shape information and reference area surface information. Based on the position information sent by each position sensor and combined with the material rack parameters, the control center derives the control command for each reflector unit and sends the control command to each reflector unit.
5. The field-type reflective screen system according to claim 1, characterized in that, Temperature measuring devices are installed at multiple temperature measuring points along the travel path; the number of temperature measuring devices is greater than the number of reflector units; each temperature measuring device sends the temperature signal of its measuring point to the control center in real time; the control center forms temperature field information in the heating chamber based on the temperature signals of each measuring point, and performs comprehensive analysis based on this temperature field information to derive control commands for each reflector unit, and sends the control commands to each reflector unit.
6. The field-type reflective screen system according to claim 5, characterized in that, Each reflector in the target working posture satisfies the following condition: the normal of the reflector surface is oriented to varying degrees toward the temperature field trough that is closer to the reflector.
7. The field-type reflective screen system according to claim 6, characterized in that, The degree to which the normal of the reflective surface of the reflective screen in the target working posture is oriented toward a nearby temperature field trough is related to the gradient of the temperature signal of the adjacent temperature measuring point directly opposite the reflective screen unit in the direction of decreasing towards that temperature field trough.
8. The field-type reflective screen system according to claim 7, characterized in that, When a reflector is in the target working posture, the angle θi between the normal of the reflector surface and the plane passing through the axis of rotation of the reflector and the temperature measuring point located at the nearest temperature field trough satisfies the following relationship: cosθi=C0+C1·∣Gi|-C2·di; C0, C1, and C2 are calibration coefficients related to the structural dimensions of the heating chamber and the reflectivity of the reflective surface. i is the number of the reflective screen; Gi is the overall temperature gradient, used to characterize the overall cooling gradient trend of the three adjacent temperature measuring points directly opposite the reflector unit along the direction towards the valley of the temperature field. di is the straight-line distance from the axis of rotation of the reflector to the center of the nearest temperature field trough; Where Gi = ((Ti2-Ti1) / (x2-x1)+(Ti3-Ti2) / (x3-x2)) / 2; x1, x2, and x3 are the position coordinates of the three adjacent temperature measuring points directly opposite the reflective screen unit along the material rack traveling direction; Ti3, Ti2, and Ti1 are the real-time temperature signals corresponding to the three temperature measuring points.