We've touched on the use of additional receivers to help in the natural cooling and de-watering of your compressed air. Let us now give some consideration to the overall plumbing in your plant and how following some fundamental rules will help in your compressed air treatment and reduce free water in the air lines.
And we all know that gravity works, right? Why not plumb your plant so that gravity works for you?
When water condenses in your compressed air lines, (it is almost inevitable that it will) that water can be removed from your air lines through sensible plumbing rather than it flowing into your end applications and causing all sorts of problems. Get the water out before it gets to your air tools, your air valves and your cylinder / actuators, and there's no more problem.
I recommended earlier that as the air exits the compressor receiver, that it should flow through an appropriately sized compressed air filter and then straight up to the ceiling in the plant. Rather than using an elbow to turn the line up, consider installing a Tee.
Install the Tee so the two ports are vertically oriented. Plumb your air line from the top port up to the ceiling, and plumb a line from the bottom port to either an electric or float type auto drain.
Plumbed this way, as the compressed air climbs up to the ceiling in the plant, it will start to cool, and, as it does, water will condense. The water will flow back down to the drain at the bottom of the vertical line. The float type or electronic auto-drain will automatically expel the collected water.
When the ceiling-height air main is installed, ensure that all lines have a gentle slope to the farthest end of the plant from the compressor.
As air flows around the plant it will cool further and free water will form. Having the entire ceiling line on a gentle slope to one location will allow all the water that condenses in that ceiling main to flow to one location and flow down one drop leg to an automatic or float type drain near the floor.
Not if you take your drop lines off the top of the air mains as shown in the next graphic.
Rather than free water running down each drop leg to the machine, water that collects in the mains now will only run to the one location in your plant. All the water that collects in the air main will then flow down one drop leg to be drained regularly at the bottom.
Yes, it is extra work and cost to plumb your drop lines as shown in the drawing. The upside of installling the air mains with a water-reduction orientation is a reduced maintenance on the machine and a reduction in machine down-time to perform needed maintenance. Over the longer haul, plumbing properly will save equipment wear and tear, frustration and money!
If your plant has an air ring, then any one drop leg for air can pull air from both directions, reducing the potential for compressed air starvation at that machine.
The air in your receiver and air mains has been reaching it's dew point, and more and more of the air vapor in your compressed air has been condensed into free water and removed using the methods discussed.
Sometimes natural water elimation from the air tank and mains does not provide dry enough air. That being the case in your plant, Here's information about drying compressed air with aftercoolers and refrigerant dryers.