Re: How long would it take to dry clothes using 'Vacuum Drying' ?

Date: Tue Nov 25 17:55:32 2003
Posted By: Gary Treistman, Undergraduate, Gen. Knowl. Dept., Programming Technologies
Area of science: Engineering
ID: 1068802999.Eg
Message:

I think your question comes down to simply "How long would it take to evaporate (or boil away) 4kg of pure H2O" To answer that question you need to know the temperature the H2O is being submitted to, and the pressure it is exposed to. You provided a link to a vacuum pump, and you cite a pumping speed of 5 cfm. The pump you cited "can" get down to .01 Torr, so that is what I assume you are working with. But you still didn't cite the temperature. The fact that the water is tensioned to clothing I believe would slow things down a bit, but not by more than 10% if the clothes are agitated. So, if you knew the temperature the H2O was at, the pressure being .01 Torr. The time it took would actually depend upon how much heat you can transfer to the water in a unit time, because if the water was actually spontaneously made to be a temperature above the boiling point at .01 Torr it would instantly "dry". The instant some of the water boils, it reduces the temperature of the remaining water to less than boiling temp. This just goes to an analysis. I think your question, and the factors needed, are incomplete to make a proper analysis. For you edification, see: http://van.hep.uiuc.edu/van/qa/section/States_of_Matter_and_Energy/Boiling_ Evaporating_and_Condensing/976072539.htm

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