Vacuum Solar Panel Envelope Sealing Before Frame Welding
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Solution Overview
Problem
The existing manufacturing methods for vacuum solar thermal panels are costly and complex due to the need for high-precision machining and accurate temperature control to prevent mechanical and thermal stresses that can damage the glass-metal seal during the welding process.
Innovation Solution
A method involving the formation of a bi-metal strip by joining two metal strips, which are then shaped into a peripheral frame and belt, with the peripheral belt sealed to the glass front plate before welding the metal bottom plate to the frame, reducing thermal and mechanical stresses on the glass-metal seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the peripheral belt is welded to the peripheral frame after sealing to the glass front plate, then the vacuum-tight envelope is formed, but thermal and mechanical stresses damage the glass-metal seal
Solution Approach 1:
The peripheral belt is sealed to the glass front plate before welding to the peripheral frame. This preliminary sealing action protects the glass-metal seal from subsequent thermal and mechanical stresses during the welding process, eliminating the need for high-precision machining while ensuring vacuum tightness.
2Manufacturing precision
If high-precision machining or moulding is used to achieve very good dimensional match between peripheral frame and peripheral belt, then welding seam without discontinuities is achieved, but manufacturing cost and complexity increase greatly
Solution Approach 1:
By performing the sealing operation before welding, the invention eliminates the need for high-precision dimensional matching between the peripheral frame and belt. The sealing step is performed when components are still relatively simple, and any dimensional variations are accommodated during the flexible sealing process rather than requiring precise pre-machining.
Solution Approach 2:
The conventional sequence is inverted: instead of welding first then sealing, the invention seals the peripheral belt to the glass front plate before welding it to the peripheral frame. This reversal allows less precise components to be joined effectively, as the sealing step compensates for dimensional variations.
3Manufacturing precision
If high precision firing jig and extremely accurate temperature control are used during glass-metal seal formation, then deformation of peripheral belt is minimized, but manufacturing cost increases greatly
Solution Approach 1:
The sealing operation is performed as a preliminary step before welding, when the peripheral belt has not yet been deformed by welding heat. This timing allows the use of simpler, less expensive sealing equipment without requiring high-precision firing jigs or extremely accurate temperature control systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method reduces the complexity and cost of manufacturing by minimizing the impact of welding on the glass-metal seal, allowing for a more robust and cost-effective production process while maintaining vacuum tightness.
Implementation Method 1
The bi-metal strip comprises a first metal strip and a second metal strip, the second metal strip having a thermal expansion coefficient matching that of the glass front plate
Implementation Method 2
the other side is attached to the glass front plate by means of a vacuum-tight glass-metal sealing of known type
Implementation Method 3
joining the metal bottom plate to the peripheral frame
Data Source
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AI summary
The present application relates to a reliable and inexpensive method for manufacturing a vacuum-tight envelope for a vacuum solar thermal panel, said vacuum-tight envelope being defined by a glass front plate (1) transparent to solar radiation, a metal bottom plate (2), a peripheral frame (3) joined to the metal bottom plate (2), and a peripheral belt (4) connecting said peripheral frame (3) to the glass front plate (1); said method comprising the following steps: - joining edge to edge a first metal strip to a second metal strip in order to form a bi-metal strip, and then joining together the opposite ends of said bi-metal strip in order to form a closed loop; - after said joining step, forming said first metal strip into the peripheral frame (3) and said second metal strip into the peripheral belt (3); - after said joining and forming steps, sealing the free edge of the peripheral belt (4) to the glass front plate (1); - after said joining and forming steps, joining the metal bottom plate (2) to the peripheral frame (3).