I designed and built a controller for my compressed air system which incorporates a delay panel so when the pressure switch engages, an air dryer and aftercooler fan start. Then 45 seconds later the compressor turns on. This allows the air dryer to chill down for the recovery cycle and prevents me from having to keep the dryer constantly running. Automation. Its everywhere! 
I used the laser cutter to make the mounting panel for the components in the controller box.
The large auxiliary device in the picture is the air dryer which (through refrigeration) chills the compressed air (hot and compressed air holds a greater amount of moisture) and drains the moisture. The added advantage is the way I have the system set up:
Right out of the pump, 200+ degree air is passed through the tube and fin fan powered after cooler. The after cooler alone drops the compressed air temp down to ambient and drops out a significant amount of moisture!
Think of drying compressed air almost like wringing a towel (but with a slight difference).
- The towel represents air
- At atmospheric pressure (uncompressed air), the towel is dry
- As the air is heated and compressed, the towel begins to collect and hold water (wet air)
- As the compressed air cools (or when going from a high pressure to a low pressure such as in a paint sprayer or blower), this is like wringing the towel out causing the water to drop out of the air.
So the initial after cooler wrings the towel / air out and that is automatically drained with the filter attached directly after. The air then goes to the refrigerated air dryer that takes the air temp down even further to near freezing. This squeezes even more water out from the compressed air. This water is automatically drained as well.
The DRY air is then stored in the receiver (the tank) and therefore I never have any moisture in the tank. And I never have any moisture in the lines. And I never have any moisture going to my tools or laser.
A small addition I made when I installed the system was adding that blue blower (in the picture) just below the compressor. It automatically comes on with the air dryer and pulls in outside air from the vent into the compressor shed (to help keep the heat buildup down). It makes a big difference!
