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Heating/cooling coils in chromic anodizing

1999

Second request!

We need some advice heating/cooling coils in a chromic anodizing bath, Our coils are made from stainless steel and are placed alongside of the bath Behind the cathodes. The coils are deteriorating rapidly and you can see exactly the " hot spots " Or large areas that are gone (especially directly behind or under the cathodes) The tank is made of PVC. Do you suggest we install Titanium coils (we can anodically protect them) ? Do you suggest we install electric insulators so to avoid stray currents from Reaching the chillers and steam boilers ? hope you can help us.

Thanks in advance, Jack

Jack stone
Israel

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You definitely need a dielectric insulator in the piping, right at the coil. Dielectric unions are available, but high pressure hose (like radiator hose) works fine too.

I would be leery of titanium, depending on the voltage you employ. As you may know, titanium per se is not corrosion resistant, the titanium oxides which you maintain via anodic protection provide the corrosion resistance--but they have a breakdown voltage which could be far less than 40 volts. Titanium can be a fine material, but I have seen so many scrap-heaps of perforated coils, burned out anode baskets, and dissolved electric heaters that I don't specify it except with the specific concurrence of the vendor's engineering department.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1999