Abstract: A mass-transfer apparatus comprises a vertical cylindrical housing, contact trays accommodated inside said housing and made up of perforated and non-perforated sectors, the neighboring trays being arranged so that the perforated sectors thereof overlie the non-perforated sectors and vice versa, overflow passageways of said contact trays positioned on said non-perforated sectors, overflow deflectors arranged on said contact trays, and baffles adapted to extend downwardly from each of said contact tray from the borderline between said perforated and non-perforated sectors and inclined towards said perforated sector.

Abstract: A mass exchange apparatus comprises a vertical cylindrical casing having pipes for admission and discharge of a liquid and a gas or a vapor. Contact plates having perforations for the passage of a gas or a vapor are arranged along the height of said vertical cylindrical casing. Each of said contact plates is provided with a central overflow device or two peripheral overflow devices, respectively, in an alternating fashion and consists of two identical segments which are secured along their chords to a central box. The axis of said central box coincides with the axis of said vertical cylindrical casing. The length of said central box substantially corresponds to the diameter of said vertical cylindrical casing. Said central box has parallel rows of apertures located above the level of said contact plates. Said central overflow devices are arranged inside said central box.