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Friobernal
17-02-2003, 07:32 PM
Hi all;

Iīve heard that there are problems in refrigeration chambers with cheese and the aluminium fins of the evaporators. Somebody told me about lactic acid.

Could anybody gives a chemical reason?

On the other hand, Does anyone know another bad combination between any product and evaporatorīs materials?

Regards

coriolan
23-02-2003, 10:42 AM
In my experience I saw evaporators literally destroyed when they were in an environment rich in acid atmosphere. Typical examples are foods preserved with vinegar, or dried pork meat preserved with nitrite... In the worst cases, when touching the fins, they became powder... Really shocking, even thinking about what they put in the food we eat.
Greetings.

Friobernal
23-02-2003, 07:55 PM
And do you think that it is enough with a epoxy or cataphoresis treatment in the fins or it would be better using copper fins?

Thanks for answering

coriolan
24-02-2003, 07:53 AM
The treatments you talk about can surely help. But the best solution is to suggest the customer to hermetically close the product in boxes or packets before storing them in the cold room... If this isn't possible, consider the chance it'll be necessary to change the evaporator each three or four years.. (even less, if unlucky). Copper fins wouldn't help, since copper react to acidity as well.
Have a nice day

bersaga
24-02-2003, 04:02 PM
Dear All,

Could someone explain how epoxy or cataphoresis treatment is done ? Is it just a coating ? Thickness ? Doesn't this affect the conductive heat transfer ?

( I have an application where tobacco is stored in a temperature =controlled room. These tobacco attract weevils and the only way to get rid of them is to close the room and fog it and then release the contaminated air by some means of -ve pressure. I'm not sure what the 'fog' is made of but it 'eats' up the aluminium fins. One solution we had was to 'wrap the blower units with shrink wrapping material' and remove them once the room is well ventilated!!)

Anyone with similar experience ?

Bernard

Dan
01-03-2003, 08:18 PM
I don't know what cataphoresis is, but something handy and not too expensive is vinyl coated fins. The fin stock is vinyl coated. I see evaporators 15-years old doing quite well in deli cases and coolers.

The vinyl also limits the effect of galvanic action with the copper, since the extrusions have a layer of vinyl touching the copper.