Liquid aerating tower contg perforated trays - with bottom gas inlet and downward flow between trays and wall

A liq. aeration appts. comprises a vessel (tower) with bottom inlet pipe for the aerating gas a number of perforated plates or the like arranged at vertical intervals above the pipe, each (generally horizontal) plate has a downward hanging edge at a little distance from the vessel inner wall, thus forming a circulation passage between plate and wall. All plates may either be mounted on a vertical revolving shaft or suspended fixed from the vessel wall. Typical uses are for culture growth, gas absorption and reaction processes.