Process and apparatus for counter-currently contacting fluids

Claim 1

A CONTACTING APPARATUS WHICH COMPRISES IN COMBINATION A VERTICALLY ELONGATED COLUMN, VERTICALLY SPACED, SUBSTANTIALLY HORIZONTAL, PERFORATED PARTITIONS DIVIDING THE COLUMN INTO A PLURALITY OF CONTACTING SECTIONS, A CONDUIT CONNECTING TO THE HIGHEST CONTACTING SECTION FOR SUPPLYING LIQUID THERETO, A CONDUIT CONNECTING TO THE LOWEST CONTACTING SECTION FOR WITHDRAWING LIQUID THEREFROM, FLOW-CONTROLLING MEANS IN AT LEAST ONE OF THE AFORESAID CONDUITS, A FLUID SUPPLY CONDUIT CONNECTING TO SAID LOWEST SECTION, A FLUID WITHDRAWL CONDUIT CONNECTING TO SAID HIGHEST SECTION, EACH TWO ADJACENT CONTACTING SECTIONS BEING CONNECTED WITH EACH OTHER BY A FLUID TRANSFER CONDUIT HAVING AN UPPER OPENING ABOVE AND A LOWER OPENING BELOW THE PARTITION BETWEEN SAID ADJACENT CONTACTING SECTIONS AND EXTERNALLY POSITIONED WITH RESPECT THERETO, THE UPPER OPENING OF THE TRANSFER CONDUIT CONNECTING TO THE NEXT LOWER SECTION BEING AT A HIGHER ELEVATION THAN THE LOWER OPENING OF THE TRANSFER CONDUIT CONNECTING TO THE NEXT HIGHER SECTION, AND INTERFACE LEVEL SENSING MEANS IN AT LEAST ONE OF THE CONTACTING SECTIONS ADAPTED TO CONTROL LIQUID FLOW RATE IN RESPONSE TO VARIATIONS IN INTERFACE LEVEL BETWEEN LIQUID AND FLUID AND TO MAINTAIN THE INTERFACE IN AN ADJACENT SECTION AT A SUBSTANTIALLY CONSTANT LEVEL.