Regulating Air flow

As mentioned above, there are a lot of flow regulation methods available, depending on the type of compressor, acceptable pressure variations, air consumption variations and acceptable energy losses. Energy consumption represents approximately 80% of the total life cycle cost for compressed air, which means that the choice of a regulation system must be made carefully. This is primarily due to significant differences in performance broadly with regard to compressor types or manufacturers.

In an ideal case scenario, the compressor's full capacity could be precisely matched to its air consumption, for example, by carefully choosing the gearbox's transmission ratio (as this is something that is frequently used in process applications.) A number of applications are self-regulating, i.e. increased pressure creates an increased flow rate, and as a result, stable systems. Examples include pneumatic conveying systems, ice prevention, chilling systems etc. However, in most applications, the flow rate must be regulated. This is usually performed using regulation equipment that is integrated in the compressor.

There are two main groups of regulation systems:

Continuous flow rate regulation involves the continuous control of the drive motor or inlet valve according to variations in pressure. The result is normally small pressure variations (0.1 to 0.5 bar), depending on the regulation system's amplification and its regulating speed.

Load/unload regulation is the most common regulation method and involves the acceptance of somewhat larger variations in pressure between two limit values. This takes place by completely stopping the flow rate at the higher pressure (off-loading) and resuming the flow rate (loading) when the pressure has dropped to the lowest limit value. Pressure variations depend on the permitted number of load/unload cycles per time unit, but normally lie within the 0.3 to 1 bar range.

Learn more about regulating dynamic compressors.

Learn more about regulating displacement compressors.