fractionating column vs strainer

fractionating column

noun
  • An apparatus for the separation of the volatile components of a liquid by means of fractional distillation, sometimes accompanied by selective adsorption 

strainer

noun
  • A device through which a liquid is passed for purification, filtering or separation from solid matter; anything (including a screen or a cloth) used to strain a liquid. 

  • A perforated screen or openwork (usually at the end of a suction pipe of a pump), used to prevent solid bodies from mixing in a liquid stream or flowline. 

  • One who strains. 

How often have the words fractionating column and strainer occurred in a corpus of books? (source: Google Ngram Viewer )