Compressor Tank Location

Location of receiver or compressor tank; what is the proper location of receiver, before or after the air dryer?

Ken from Houston poses this question:

Our engineer has had our compressed air system reworked so that the air from the compressor goes to the air dryer first, then to the receiver, then to the plant.

The pipe to the receiver is then teed off the pipe to the plant.

Originally it went to the receiver first, then to the dryer, then to the plant.

The air does not flow through the receiver, it acts more like a storage tank with only one pipe to it instead of in and out separate piping. Old schoolers do not think this is the way to do it.


My Response

Hi Ken, and thanks for the question.

If you think about it, the reservoirs (receivers) job is to store compressed air that is ready to use to supply instantly to fill shop demand for compressed air.

As the pressure in the shop lines begins to drop when the compressor cannot keep up, compressed air is automatically bled into the lines from the receiver. Compressed air will always flow from higher pressure to lower pressure areas, from tank to air tank, and from air tank into the shop mains, then into the drops, the air lines etc.

It is when the compressed air pressure throughout the whole system, which also includes the compressor air tank, falls to the compressor kick in point that the compressor will start and pump air into the tank and the air system to raise the air pressure throughout to the compressor cut out.

When the system air pressure reaches the compressor cut out point, the compressor will stop compressing air.

It does not matter to the system where, in the grand scheme of things, the receiver is positioned.

Your engineer has determined (I think) that it is better for your plant to store compressed air that has already been dried, so it is ready to use right away, without having to go through the plant dryer first.

Others will put the receiver before the dryer, hoping that the compressed air in the tank the opportunity to sit awhile before being pulled downstream. Compressed air that has dwell time in the tank will be cooled by natural heat loss, with water loss in the receiver beginning the drying process, and with already-cooler air entering the dryer as a result. That is better for the dryer efficiency, in my opinion.

I do not know if that provides a benefit in your case though. Your plant compressed air demand may be so high that the only time air in the receiver might have time to cool is between shifts.

Regardless of where the dryer is, I would still have an auto drain cycling periodically on the receiver tank drain to ensure that if there is any condensation in that tank, it gets bled out regularly before it needs to be purged by the dryer.

There you go, as you asked comments. ;-)