Continuous-Flow Heater Frame Welding for Steel-to-Aluminium Sealing
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Solution Overview
Problem
Continuous-flow heaters face challenges in achieving reliable sealing between the heating plate and the housing due to temperature fluctuations, as the steel substrate of the heating plate cannot be welded directly to the aluminium-based alloy housing, and traditional sealing methods are impractical.
Innovation Solution
A frame made from a material with a thermal expansion coefficient between that of the aluminium-based alloy and steel is embedded in the housing wall, allowing the frame to be welded to both the housing and the heating plate, eliminating the need for a sealing ring and minimizing mechanical stresses from thermal expansion differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing ring is used to seal between the heating plate and housing, then sealing reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes the sealing ring component entirely by creating a direct weld joint between the heating plate and housing. The weld seam itself serves as the sealing barrier, eliminating the need for separate sealing elements and reducing structural complexity while maintaining sealing reliability.
Solution Approach 2:
The patent combines the sealing function with the structural connection function by using a weld joint that simultaneously provides both mechanical attachment and fluid sealing. This merging of functions eliminates the need for separate sealing components.
2Ease of manufacture
If the steel substrate of the heating plate is welded directly to the aluminium-based alloy housing, then manufacturing simplicity is improved, but welding feasibility deteriorates due to material incompatibility
Solution Approach 1:
The patent introduces an intermediate layer (which could be a transition material or coated surface) between the steel substrate and aluminium housing that enables welding compatibility. This intermediary layer allows the welding process to proceed while maintaining the structural integrity of both dissimilar materials.
3Adaptability or versatility
If materials with different thermal expansion coefficients are used for housing and heating plate, then material selection flexibility is improved, but mechanical stresses from thermal expansion differences increase
Solution Approach 1:
The patent modifies the thermal expansion parameter by selecting specific aluminium alloy compositions or steel grades with matched thermal expansion coefficients. By adjusting material parameters to be more compatible, the patent reduces thermal stress while maintaining the benefits of using dissimilar materials for their respective functional advantages.
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 solution provides a cost-effective, leakproof joint that reduces mechanical stresses and prevents fluid leakage by matching the thermal expansion coefficients of the materials, ensuring efficient heat transfer and housing integrity.
Implementation Method 1
provision is made for the frame to be made from a material whose coefficient of thermal expansion lies between the coefficient of thermal expansion of the aluminium-based alloy and the coefficient of thermal expansion of the steel from which the substrate of the heating plate is made. In this way, it is possible to reduce the mechanical stresses that can be generated by differential thermal expansion of housing and substrate
Implementation Method 2
a flow channel for a fluid to be heated runs from an inlet to an outlet, and a heating plate arranged in the housing
Data Source
AI summary
A continuous-flow heater is described, with a housing made from an aluminium-based alloy, in which a flow channel for a fluid to be heated extends from an inlet to an outlet, and a heating plate which is arranged in the housing, with a substrate made from steel, which carries heating conductor tracks, a frame embedded in a wall of the housing, wherein the heating plate forms one wall of the flow channel in the housing, and is welded to the frame.