Introduction: Compressed Air Dryer
This will make sandblasting and painting much easier!
You can purchase commercial dryers, which I did, but it was small and took little time before the desiccant was exhausted. Capacity too low. I saw a YouTube video by "Hanna's Bug" Amazing young teen girl who does it all! who had made something similar but twice the size. I wanted something effective but a bit smaller.
The first image has pretty much everything you need to know.
Materials consist primarily of 2" schedule 40 PVC water pipe with a few other fittings and bits thrown in. The design can easily be expanded to 3" PVC if you want higher capacity or less frequent bead changes.
If you want to get all fancy, replace the PVC with clear schedule 40 PVC so you can see the color of the beads. Short sections can be purchased on eBay for under $20. I did not want to wait! but I may modify mine later.
The principle is same as in Hanna's YouTube but simplified. rather than two tees and two reservoirs I stacked them. Instead of the built in funnel to add desiccant, I made the whole tube unscrew from the tee for recharging.
The center air tube I glued into the bottom separator but you MUST leave it free at the top so it can be removed to change beads. I filed a bit of a taper on the 1/2" pipe to make it easier to align when rejoining the sections.
While the over all pressure rating is about 250 psi, I suggest you limit to maximum 120 psi for safety.
Most sandblasting and spray painting jobs won't need that much pressure anyway.
PVC if stressed will not stretch, it will EXPLODE sending shrapnel in all directions. It is suggested you build a nice, pretty (or not) housing to act as shield...just in case. Keep it out of sunlight too as UV will really destroy PVC in time!
Desiccant beads: I bought a 5 pound can of blue indication type on Amazon. You can get them on eBay or perhaps a local store that sells supplies and tools related to air compressors and spray painting. I like the blue because they change color to pink when exhausted. Put them on a cookie sheet and bake in oven to recharge.
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Step 1: Page Two
This is the finished assembly. I do not provide any dimensions as those are not critical and you can use bits and pieces. You could make it longer or shorter based on your needs and the amount of desiccant it will hold.
As you can see there are two pieces of 2" making up the body. At the top is a male adapter which threads into the bottom of the tee to enable disassembly for recharge.
The middle coupling contains the separator disk. Both pieces of PVC must be securely glued into this coupling. On the bottom is a glued coupling with a 2" to 1/2" reducer into which I screwed a valve to drain condensation.
On the top, the tee is smooth left and right with threaded bottom. On the air inlet side is a 2" - 1/2" reducer smooth. You need to remove the pipe stop such that a piece of pipe can slide all the way through to locate the 1/2" ell centered in the bottom hole of the tee. I did this on a mini lathe but you can accomplish same task with a half round file. The pipe that goes here is the only critical piece in terms of length. You need to push in and place the ell, dry fit, and make sure it is centered as shown in following images. Once you have that location, pencil mark the pipe to locate its position in the reducer. Back that pipe out, glue and push back in quickly to fix into place. Then you can reach in and glue the ell in place, turning to assure it is concentric with the opening in the tee. Again..the bottom of this 1/2 ell will NOT be glued.
On the outlet side tee the reducer is 2" to 1/2" female threaded into which you can screw your air fittings.
Step 2: Bead Separator
This is about the only custom piece you need to make. It is a disk of, in my case, 1/4" HDPE I had laying around. You could use just about any material such as sheet PVC, Plexiglas, even 3/16 plywood. It is just a separator keeping desiccant in the upper chamber from falling into the lower reservoir. Does not even need to be 1/4" thick. 1/8" would be just fine. I used larger holes because I am lazy. A piece of window screen over those keeps your beads from falling through. You could just drill many more smaller holes of a diameter smaller than the beads and accomplish the same thing.
Step 3: Separator Section Cont.
Another view showing the 1/2" PVC adapter before adding screen.
Once the screen is placed over the small holes, glue the 2" PVC pipe into the top and the shorter PVC into the bottom. The top PVC will hold the separator in place permanently.
Second photo shows the separator with the air inlet pipe glued in place. You need to adjust the length of this center 1/2" inlet tube such that when the 2" reservoir screwed tightly into the tee, this pipe is snug in the concentric 1/2 elbow. As you add beads, hold this pipe as close to dead-center as you can...it will make assembly much easier.
The air inlet tube is NOT glued into the ell in the 2" tee. If you do this your screwed!
Step 4: View Looking Into Tee.
This is the top showing the air inlet pipe centered in the tee. Get it right!
Everything you see here is glued air tight.
Step 5: Inner Ell Concentric With Tee.
Tee again. Notice how center pipe concentric with opening in tee.
Since I was planning on using standard 1/4" air fittings, I used two galvanized 1/2 - 1/4 reducers on both inlet and outlet sides of tee. On the inlet side you need to glue a female adapter to the 1/2 pipe then screw the reducer into that. Use PTFE Tape on all threaded joints.
Of course you may alter these connections to suit your installation. Perhaps you are going to place a regulator on the inlet side and my need to use just a 1/2 pipe nipple. Do as you need for your system.
Hang in on the wall and, perhaps, enclose with a simple box as added protection in the unlikely event of a rupture.
In operation: Just insert this between your air compressor and your air tools to help eliminate moisture. Make sure you depressurize your system prior to removing the reservoir from the tee when recharging with new beads.