Plate Heat Exchanger Brazing With Rapid Heating and Pressure Forming
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Solution Overview
Problem
Existing plate heat exchanger manufacturing methods are costly, complex, and result in reduced dimensional accuracy and limited material selection, with prolonged heating processes leading to weakened soldered connections and limited use of high-strength aluminum alloys.
Innovation Solution
A method involving two metallic plates with a soldering material in between, heated to a first temperature for internal pressure reshaping to form channel structures, then soldered at a second temperature, with a short cooling period to create stable eutectic microstructures, allowing for flexible material use and high dimensional stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plates are soldered using conventional oven processes, then soldered connections are formed, but the prolonged heating process (1-2 hours) causes magnesium precipitation that weakens the connection
Solution Approach 1:
The patent applies rapid heating to reach soldering temperature within seconds rather than conventional slow heating over hours. This parameter change in heating rate prevents magnesium precipitation by drastically reducing the time window for harmful phase transformations, thereby maintaining connection strength while eliminating prolonged exposure to heat
Solution Approach 2:
The invention rushes through the critical heating phase by applying rapid thermal energy input, completing the soldering process in seconds instead of hours. This approach skips through the dangerous time window where magnesium precipitation occurs, directly achieving strong soldered connections without the weakening effect of prolonged heating
2Strength
If high-strength aluminum alloys are used, then material strength is improved, but magnesium precipitation occurs during conventional soldering which weakens the connection
Solution Approach 1:
The patent changes the heating parameter from conventional slow heating to rapid heating, enabling the use of high-strength aluminum alloys without magnesium precipitation. The rapid heating process completes soldering before harmful precipitation can occur, allowing the full strength benefits of these alloys to be realized in the final connection
3Strength
If roll-bonding process is used to connect metal sheets, then permanent connection is achieved, but dimensional accuracy decreases as plate size increases
Solution Approach 1:
The patent replaces the mechanical roll-bonding process with a thermal soldering process. Instead of relying on mechanical pressure and rolling to create connections, the invention uses controlled thermal energy to melt solder material and form strong joints, thereby maintaining dimensional accuracy even for large plate sizes while achieving permanent connections
4Reliability
If conventional soldering processes are used, then complete soldering is achieved, but cycle times of one to two hours are required
Solution Approach 1:
The patent dramatically changes the thermal parameters by applying rapid heating rates that reach soldering temperature in seconds. This parameter transformation enables complete soldering penetration and strong connection formation while reducing the cycle time from hours to seconds, thereby simultaneously achieving high reliability and productivity
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 manufacturing costs and cycle times, enhances dimensional accuracy, and prevents magnesium precipitation, enabling the use of high-strength aluminum alloys for durable and long-lasting plate heat exchangers.
Implementation Method 1
heating the plates to a first temperature
Implementation Method 2
forming channel structures by local internal pressure reshaping of at least one plate under application of pressure by the tool
Implementation Method 3
heating of the plates to a second temperature, soldering connection of the plates on the surfaces in contact
Implementation Method 4
soldering connection of the plates on the surfaces in contact
Implementation Method 5
cooling of the plates (1, 2) after the soldering connection
Implementation Method 6
the cooling period between the soldering connection and the solidification of the solder is less than 60 seconds
Implementation Method 7
create stable eutectic microstructures
Data Source
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AI summary
The invention relates to a plate heat exchanger (15). Two plates (1, 2) made of a metallic material are provided and brought into contact with each other, with a brazing material being placed between them. The plates (1, 2) are heated to a first temperature (T1). The plates (1, 2) are placed in a mold (6) whose forming surfaces (9) have cavities (10) for channel structures. Channel structures are formed by local internal pressure forming of at least one plate (1, 2) under pressure from the mold (6). The plates (1, 2) are heated to a second temperature (T2). The plates (1, 2) are then brazed together at their contact surfaces.The plate heat exchanger (15) comprises two plates (1, 2) made of a metallic material, wherein channel structures are formed in at least one plate (1, 2) and the plates (1, 2) are soldered together apart from the channel structures, wherein eutectic microstructures with a longest extent of less than 50 micrometers are formed in the solder layer.