Source : Webster's Revised Unabridged Dictionary (1913)

Precipitator \Pre*cip"i*ta`tor\, n. [L. praecipitator an
   overthrower.]
   One who precipitates, or urges on with vehemence or rashness.
   --Hammond.

Source : WordNet®

precipitator
     n : removes dust particles from gases by electrostatic
         precipitation [syn: {Cottrell precipitator}]