# Dryers for filtration



## hrushi (Oct 3, 2014)

Hello guys

I have vacuum filtration system which includes funnel, flask and oil vacuum pump. Yesterday I had put my cloths for washing in washing machine I saw dryer, idea came to my mind that can we put PP bag in dryer and pass solution through dryer and use it cor filtration.

Advantages of dryer 
1. Low maintenance
2. More economical
3. Less time
4. More effective
5. Less space

Comments/suggestion are welcomed.

Thank you
Hrushi


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## Lou (Oct 3, 2014)

Sure can. They work great for spinning off electrolyte from a silver cell. Just need to plumb them in SS304.

Lou


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## Gratilla (Oct 3, 2014)

If you're looking to drying, seriously consider dehumidification over heating. Here's a link to how it's taking over in the construction industry.

http://www.awci.org/cd/archiveArticles.pl?id=1017, A Comparison: Dehumidification Versus Heat in Construction Drying Applications.

The science states that drying rate depends on the (partial) pressure of water in the system and while heating will decrease the relative humidity, the total moisture in the system stays the same - unless you ventilate/replace your moist hot air with fresh air; this will lose energy unless you include a heat exchange system further complicating the setup. A dehumidification system can be as simple as a plastic bag with your target to be dried and a tray of (chemical) desiccant to suck up your moisture (ie decrease your vapour pressure).

Coincidentally, I've just built myself a (hybrid) dehumidification (solar heating) kiln for drying teak using calcium chloride (CaCl2) as the desiccant. There are many other desiccants (such as calcium sulfate ie gypsum, etc), but the interesting thing about calcium chloride is that it's also deliquescent ie it continues to absorb water even after its dissolved itself into solution. It works great. I'm now working on regenerating (ie drying) the calcium chloride so that it can be recycled.


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## Silver Sliver (Oct 3, 2014)

Gratilla said:


> Coincidentally, I've just built myself a (hybrid) dehumidification (solar heating) kiln for drying teak using calcium chloride (CuCl2) as the desiccant.



I am new and still learning but I think you meant CaCl2 instead of CuCl2. My apologies if I am in error.

I do find your process interesting though and I would like to see some pictures of your hybrid machine.


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## Gratilla (Oct 3, 2014)

You're right. Corrected. Thanks.

As for pictures, I'll see what i can do. I've just taken it apart though, to tweek a couple of identified problems with this version 1.

If a description helps though:

I started with a 355cm long x 155cm wide x 120cm deep concrete tank. (The hectare that I'm on used to be a shrimp hatchery and I've a number of different dimension "fish" tanks waiting for a useful purpose.) I stuck a strip of 1cm thick rubber sheet around the top edge to provide a fairly hermetic seal with the 3.5cm x 3.5cm steel frame I'd had made. For a quick and dirty kludge, I then stretched a sheet of plastic over the tank, and kept it in place by the weight of the steel frame. I put 12 rough-sawn teak beams and four plastic trays of calcium chloride under the wood in the tank, replaced the plastic and steel frame and left it for one day (a sunny 32 deg C) and one night.

My first impression the next day was that my system didn't work. The plastic had sagged and a large amount of condensation (resulting from the overnight drop in temperature) had dripped onto and soaked my wood. The calcium chloride, protected from the condensation, had soaked up a lot of moisture and had even deliquesced; One tray had even overflowed. In retrospect, although the efficiency of the CaCl2 the solar heating part were confirmed, a redesign was in order. I'll (1) find a stiffer plastic that won't sag and (2) build a wood frame for the steel to rest on at an angle so that condensation can run down to an exit point at the side of the tank.


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## Lou (Oct 3, 2014)

We use CaCl2 with a color changing indicator for drying gases before they go to instruments. Works pretty well.

What works really well is P2O5/P4O10...use that for the vac dessicator.


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## hrushi (Oct 13, 2014)

Guys I was thinking of filtration not drying.
We can make dryer in titanium shell and use it for AR filtration
Hrushi


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## 4metals (Oct 13, 2014)

I have used stainless steel spin dryers to spin dry rinsed silver needles harvested from silver cells. The stainless baskets are lined with custom made bags made by an anode bag manufacturer to hold the fine crystals. The setup would work for solution as well but only silver electrolyte because the spinners are 304 stainless. 

This is the drier, the rinse tanks for the silver needles are behind the drier. There is an overhead hoist to lift and move the basket along through the rinses and place it in the spin dryer.


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