Method for manufacturing a vacuum solar thermal panel and related vacuum solar thermal panel
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Solution Overview
Problem
The manufacturing of vacuum solar thermal panels is complicated and costly 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, which is then shaped into a peripheral frame and belt, with the peripheral belt sealed to the glass front plate before joining the metal bottom plate to the frame, reducing thermal and mechanical stresses on the glass-metal seal by aligning and inclining the joining edges to minimize tangential stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the peripheral belt is sealed to the glass front plate before welding the metal frame, then the glass-metal seal is protected from mechanical stresses, but the manufacturing process becomes more complex
Solution Approach 1:
The peripheral belt is sealed to the glass front plate before the welding of the metal frame, performing the sealing action in advance. This preliminary sealing protects the glass-metal seal from subsequent mechanical and thermal stresses during the welding process, while the bi-metal strip's inherent flexibility accommodates dimensional variations without requiring high-precision machining.
2Manufacturing precision
If high-precision machining is used to achieve very good dimensional match between peripheral frame and belt, then welding seam quality improves, but manufacturing cost increases
Solution Approach 1:
The invention changes the material parameter of the peripheral belt by using a bi-metal strip with specific thermal expansion properties. This allows the belt to flex and accommodate dimensional variations in the metal frame without requiring high-precision machining, thereby reducing manufacturing costs while maintaining welding seam quality.
Solution Approach 2:
The peripheral belt is constructed from a bi-metal strip, which is a composite material made of two different metals bonded together. This composite structure provides both the necessary mechanical properties and the thermal expansion characteristics needed to match the glass front plate, eliminating the need for high-precision machining of the frame and belt.
3Manufacturing precision
If accurate temperature control is implemented during thermal process, then deformation of peripheral belt is minimized, but manufacturing complexity increases
Solution Approach 1:
The bi-metal strip is specifically selected to have a thermal expansion coefficient that closely matches that of the glass front plate. This thermal expansion property allows the peripheral belt to expand and contract in sync with the glass during temperature variations, minimizing deformation without requiring complex temperature control systems or high-precision firing jigs.
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 simplifies the manufacturing process by reducing the complexity and cost associated with high-precision techniques, while maintaining the integrity of the glass-metal seal by minimizing stresses during the welding process.
Implementation Method 1
The peripheral belt, made out of a metal alloy with a thermal expansion coefficient closely 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
the welding between the metal peripheral belt itself and the metal peripheral frame is performed
Data Source
AI summary
A method for manufacturing a vacuum-tight envelope for a vacuum solar thermal panel includes: 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 a peripheral frame and said second metal strip into a peripheral belt; after said joining and forming steps, sealing the free edge of the peripheral belt to a glass front plate; after said joining and forming steps, joining a metal bottom plate to the peripheral frame.