The pressurized air from a standard air compressor is fine for most uses. But some applications like plasma cutting call for low-humidity air and the hardware available to facilitate this can cost a bundle. [Roland] and his cohorts at TX/RX Labs (a Houston, Texas Hackerspace) just built this air drying system.
It works using a desiccant; a substance that sequesters moister. It’s the stuff in those little packets you find in shoe boxes and the like with a warning that you shouldn’t eat it. The image above shows two chambers which house the desiccant. Only one is used at a time, so that as it’s ability to remove moisture drops, the system can switch over to the other chamber. There’s even an automatic recharging system built in that uses a portion of the dried air to remove the humidity from the unused desiccant chamber.
There’s a functional diagram at the link above. It’s resolution is low enough that the text is almost unreadable but we’ve asked [Roland] if he can repost the image. This seems like a build in which other hackerspaces will be interested.