Both the Venturi and Impingement Plate Scrubbers rely on the creation of turbulence and high impact forces to ensure intimate contact between gas and scrubbing liquid.

The VENTURI SCRUBBER achieves this by accelerating the gas through a restricted area of 'throat'. Liquid is introduced at the throat creating the high turbulence zone. Venturi scrubbers area available with both fixed and variable throats with the efficiency being a direct function of both the throat area and the liquid rate. Venturi scrubbers can be used either as a single stage unit for removal of fine particulates or aerosols, or as part of a multistage scrubber where they maybe followed by a packed tower (for gaseous contaminants) or by successove venturi units when very high removal efficiencies are required.

IMPINGEMENT PLATE SCRUBBERS are counter-flow devices in which liquid is introduced at the top of the tower and flows down across a series of plates. These plates or baffles are perforated by holes or openings through which the contaminated air introduced at the bottom of the column flows.

Gas / liquid contact occurs in pools of liquid as the liquid attempts to pass down the same holes through which the air is rising. Zones of turbulence are formed with the scrubbing efficiency being determined by the size and shape of the openings. Sprays are also directed on the underside of the plates to provide an initial opportunity for collision to occur between gas and liquid. This also eliminates any wet/dry interfaces which may cause plugging.

Particulate matter which may be present in a gas stream can cause blockages if passed through a packed tower scrubber. Impingement Plate scrubbers are most widely used to overcome this problem.