render them unless. He offered a variety of desiccant tablets from mild to wild (cheap to expensive). I choose the best I could get a product from Clearwater Engineering called Hydro-Lith "E". Very pricey at $294.20 for a 50 pound box. However there is enough to fill two dryers and a ton left over for maintenance top offs. He also suggested the use of ceramic marbles to prevent something called "Gas channeling". Gas channeling occurs when the gas does not distribute uniformly through the Desiccant tablets, but moves only through a small portion of the bed (following the path of least resistance).

At this point the only constraints on the design will be gas flow and channeling. To get around the flow issue, I decided to put a 1 1/4" to 1" reducer at the tap point on the main line. I then used 1" pipe, valves, coalescing Filter and fittings to supply the dryers. The solution for channeling is going to be three fold. I will need to address channeling, flow and supporting the column of desiccant tablets. I decided not to use a wire screen as the brine, trace acids and other chemicals could corrode the screen away. Instead a piece of 1/4" plastic with holes drilled in it would be used. Initially, I realized there would be a flow loss in a 4" diameter plate. So I increased the surface area of the plate by designing a channeling chamber. (Pic to the right) The chamber is built out of a 6" PVC coupler. The coupler is perfect as it has an inside molded lip at the center. The molded lip will make a great shelf to sit the channeling plate on. The channeling plate can now be increased from 4 1/2" to 6 1/2". The hole size and number of holes in the plate could be calculated so the total area of holes equals the area if the 4" pipe. The 6 1/2" area also spread out the gas flow forcing it to take more routes thru the ceramic marbles and ultimately the desiccant tablets above.

I was able to obtain all the necessary PVC fittings from my local Lowe's Home Improvement Center.

1. 2" x 3/4" Threaded PVC Bushing
2. 2" PVC Street Elbow
3. 4" x 4" x 2" PVC Reducing Tee
4. 4" x 3" PVC Bushing
5. 3" PVC Drain Plug Assembly
6. 4" PVC Pipe Sch 40, 48" long (cut from 5' piece)
7. 6" PVC Coupler
8. 4" x 6" PVC Bushing
9. 6" PVC Spacer Ring (cut from end of 4" x 6" PVC Bushing)
10. 1/4" Plexiglas Plate
11. 4" PVC Pipe Sch 40, 4" long (cut from 5' piece)
12. 4" x 2" PVC Bushing
13. 2" x 1" PVC Bushing
14. 1" PVC Pipe Sch 40, 2" long
15. 1" 45° PVC Elbow
16. 1" x 3/4" Male Threaded Adapter
17. 3/4" PVC Threaded Ball Valve