Three basic types for microbial systems: Porous, nozzle and orifice
Porous sparger
Laboratory operation, usually constructed from sintered glass or metal. Disadvantages are high pressure drop and possible growth on sparger particularly in the disengagement zone, systems creates small bubbles.
Orifice sparger
Usually a cross or a curcular ring with a number of perforated holes, size and frequency of holes is dependant on size of sparger. On production vessels the size of the holes does not generally exceed 6 mm. The coalescing properties of the medium are important. Situated under the bottom impeller and should be 0.75 impeller diameter (Rushton turbine). Need also drainage holes on the under side. Most common on larger laboratory, pilot plant and production scale. Feed pipe usually from the top of the vessel.
Nozzle sparger
Very common on laboratory scale. Fishtail sparger if there is a flattened end. Easier to flood impellers but low pressure drop and large bubbles.