Case Study #4: Stainless Steel Immersion Heat Exchanger for Sealing Baths
Initial situation
In surface treatment applications like anodizing, sealing is the final process step, where the porous oxide layer formed on aluminum is closed using hot water or steam. This step significantly enhances the corrosion and weather resistance of the aluminum.
Calorplast typically supplies plastic immersion-type heat exchangers for aggressive chemical baths. However, in aqueous applications like rinsing or sealing, stainless steel (VA) exchangers can be used. While stainless steel resists the sealing bath, it is vulnerable to corrosion from regular cleaning with diluted hydrochloric acid which causes damage after only a few cycles.
Challenge
Galvabau AG in Switzerland required a heat exchanger that could:
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Handle high bath temperatures of around 98°C (208°F)
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Fit inside an open-top tank with high heat loss
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Deliver large heating capacity in a compact space
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Avoid interference with other in-tank equipment
Traditional coil or plate-style stainless steel exchangers were not up to the task due to limited surface area and physical bulk.
Solution
Calorplast developed the Calormet stainless steel immersion-type heat exchanger, available in V2A or V4A grades (304/316L). The system is engineered for high-temperature aqueous processes, providing:
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Compact, space-saving design
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High thermal performance
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Large-diameter piping options for improved flow
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Customizable connections for simple, fast installation
Result
The Calormet exchanger now reliably delivers the required heat without interfering with surrounding components. By maintaining precise temperatures, it ensures consistent sealing quality in the anodizing process while resisting the effects of cleaning chemicals longer than conventional designs.
