A suction scrubber is the last line of defence before a compressor. Liquid reaching the machine causes anything from a nuisance trip to blade damage and an unplanned outage, so the separation duty is judged on reliability rather than efficiency alone.

The design has to cope with two different threats: bulk liquid slugs arriving from upstream, and fine mist that a coarse device will pass straight through. Most designs combine an inlet device for the bulk with a mesh or vane pack for the fine fraction.