Condensation in industrial computer terminals

[mechwater]

We have a problem with condensation build up inside our computer terminal and we need either a plug, and/or valve to drain the water out or something to prevent the condensation in the first place. This terminal goes in and out of a flash freezer several times a day so the terminal goes from 90 deg's to 30 deg's below 0. Please advise.[/green]

 

[alpharam]

Hi mechwater!
I don't know, if you have to design the terminal yourself or you use some of-the-shelf, but you may wish to see what they did in Motorola. I dealt few years ago with their MW-520 mobile workstation. It has a very interesting design to take into account. First of all they seal the enclosure completely, so that the only humidity you have to deal with is inside of the device. Once it is sealed from the outer air, you don't have to care about it in most cases, because their is no air flow inside and it's naturally heated by your components. If it's still not enough, absorb it with silica gel
You have to be very careful with termal management under such conditions. Once no inner ventilation is present, you'll have to turn the whole enclosure into one big heat sink. It's a very special design and requires precise knowledge on all the details. Blow the air on your device from outside, once it's out of the freezer.
I hope this helps.

 

[Uge]

I second that, use an absorbent such as silica.
A second opinion would be to dehumidify the terminal. Do this by dropping the temperature slowly, then perform your temp shock testt, assuming you can A. seal your unit and create a closed loop dehumidifcation cycle.

Eugene
evzene@hotmail.com

 

[Tofflemire]

Hello,

Another option is to purge the system using Nitrogen, assuming you have a sealed system with a port to do so, once this is done, pressure the system with Nitrogen to about 3 PSI. We use this method with our electronics that are used in cold environments like the Artic, Icebergs...

You could also conformal coat you electronics with a spray, do a Web search, you will find information if you are interested.

Tofflemire