Quote Originally Posted by Antoni View Post
Please, can anyone explain how the pump dryers actually work?

I don't understand how a large surface area of glass (beads) dries the air but I'm not saying it doesn't (where does the water go?)

I do know from my use of refrigeration-based de-humidifiers that there's a lot of water in air. So much so that sometimes I add the de-humidifier's tank contents to my washing machine runs to soften the water for the sake of the soap function. My point - a lot of water can be pulled out of the air.

In chemistry experiments at school air involved in the experiment was pulled through a U-Tube containing Sodium Hydroxide powder so that it was completely dry, but that method would invite a disaster in an airgunning situation involving aluminium.

How do the airgun and dive bottle dryers work?
They will use dessicant to dry the air .

I used to service industrial air dryers like this

http://www.atrgroup.co.uk/product/air-drier

They would go down to -40 dew point

They used desiccant to absorb the water that made it past the water trap . One water trap and two oil filters.

The compressor would pass oil and water so the filters caught that .

The grey tubes were full of desiccant to catch the water produced by the heat of the air.

There was two banks and one would dry the air for 6 mins while the other was getting air forced through it to blow the water from the dessicant . After the 6 mins the bank's would change function so the now dried one was then absorbing the water and the other was drying the dessicant .

I don't think that type of dessicant will dry air unless it's being forced through the dessicant .

It may work in a stirrup pump though .


I have a bag of it here that I got in 2013.


More here . We used the activated alumina in the above driers .


http://theworkshopcompressor.com/lea...sed-air-dryer/