Büchner filters are laboratory devices used to perform vacuum filtration, a technique that allows for the rapid separation of a solid from a liquid. They consist of a cylindrical funnel with a perforated plate—usually made of porcelain or glass—on which a filter paper is placed. The funnel is connected to a vacuum flask (or Büchner flask) through a rubber adapter.

When a vacuum is applied, the reduced pressure speeds up the passage of the liquid through the filter, leaving the solid residue on the paper. This method is much faster and more efficient than traditional gravity filtration.

In the ceramic field, Büchner filters are used to separate precipitates during gravimetric or chemical analyses of raw materials, to collect and wash solids obtained after reactions or laboratory treatments, and to remove liquid or solid impurities from clay or glaze suspensions.