Calculating cooling needed for aluminum anodizing

A. Hi Poul. If this is Type II anodizing, operating at about room temperature, then essentially 100% of the Wattage added must be removed. However, "duty cycle" is also a factor. The tank is empty some portion of each hour, plus you start the anodizing process at lower voltage and current. Further, when people say they anodize at a given current, they are usually talking about their maximum amperage; sometimes the racks aren't full or they're anodizing smaller parts.

Luck & Regards,

• Topic 51573, "Hard anodizing chiller sizing"

A. With some exceptions, chillers are sized by the load. A quick way that is fairly close, is to consider that the entire amperage of your biggest load is all going to heat.

Volts times amps = Watts

Watts times 3.412 = BTU's

BTU's divided by 12,000 equals tons of chilling capacity

A 55 gal tank will take somewhere between a half ton and a ton, depending on your load and power supply.

The heat exchanger is a more difficult calculation for size.

Best to have a professional do that one for you.

A. Dear Larry,

Without being rude, why is your tank so small? One reason you're heating up so quickly is because the ratio of work to solution is too great.

You could try running your rinse water thru a coil in your anodising tank before it enters the rinse, otherwise you are going to have to "make something" out of a refrigerator.

I would suggest that you look to a larger tank, nothing less than 200 gallons.

regards

A. We used lead pipe (that we made) in bath for cooling. I don't know the calculations but we obtained better results than with any other stuff.

A. Hi. All of the responses sound good! But I agree mostly with John that the tank should be bigger. Then it may be that if it is loaded infrequently, just cooling with a lead pipe and the city water that feeds the rest of the line may be enough. There could be a 3-way valve that sends the water through the tank when the tank exceeds 70 degrees, and bypasses it when the temperature is lower than 70 degrees.

But don't forget a backflow preventer if connecting to city water. Good luck.

Regards,

A. That one's easy, Gap. The rectifier voltage x the rectifier amperage = watts of heat input that must be removed. But that would be for a 100% duty cycle (assumes the tank is never empty, never ramping up, and always operating at full voltage and amperage.

A. ...And^multiplydivide Watt-Hours by 3.414 to get BTUs.

A. And add to that the heat carried in by parts plus the heat transferred in through tank walls and surface and agitation air, which can be considerable in hot weather.

A. Jeffrey is right for Type III, of course, and sometimes secondary sources of heat input and outflow can be significant. But no calculation ever takes everything into account (it's always a rounded-off estimate), and if this is 68 - 70 °F (room temperature) anodizing rather than hardcoat anodizing, those factors become much less significant. The anodizing tank is never full 100% of the time, and I personally never encountered a problem designing cooling systems for room temperature process tanks based just on the anodizing or plating rectifier wattage input.

Regards,