Do I need a regulator? What does a regulator do?

Author: David J. Connaughton
Blog: Compressed Air th Fourth Utility

Why do you need a regulator? Well, maybe you don't. Regulators of compressed air control the downstream pressure within a very tight range. Precision regulators are often two stage and can be approximated with two regulators in series. But are they always needed on an air line? Regulators should be used only when the downstream "work" that the compressed air is doing is sensitive to variations in pressure. Compressed air systems typically go up and down in pressure depending on the compressor's cycling and system demand. Spray painters should be especially careful to specify regulators because without them the air pressure to their gun will go up and down so the flow of paint from the nozzle will go up and down. Fluctuating flow changes how much paint is laid down. Air dryers, on the other hand, don't need a regulator up stream of them unless there is a chance that the air supply pressure can exceed the max pressure of the dryer. Dryer performance tends to improve with higher pressure due to a longer residence time at a given flow rate. So, as long as the performance is met at the minimum system pressure a regulator is not needed. Or is it?

Regulators serve another important function. Energy conservation. If your process only requires 60 psig, then setting your regulator to 60 psig assures that excess air is not wasted.

It is important to note that regulators do not control flow. At least not directly. Flow is governed by a valve or a fixed orifice. The flow through the valve is a function of the valve's upstream pressure so a given valve opening or orifice size, flow through it is less at 60 psig than it is at 100 psig. If there is no restriction of the air downstream of a regulator, the regulator will pass the maximum amout of air it can handle.

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