Percolator

n.
  1. One who, or that which, filters.
  2. A type of coffee pot in which the heated water is driven by its boiling action up above a porous canister of coffee held above the level of the water in the pot, and then filters (percolates) back through the coffee thus extracting its essence.
  3. (Pharmacy) An apparatus for producing an extract from a drug by percolation.