Chemical recovery unit

Claim 1

A CHEMICAL RECOVERY UNIT COMPRISING IN COMBINATION A FURNACE INTO WHICH THE RESIDUAL LIQUOR OBTAINED IN THE MANUFACTURE OF PULP IS INTRODUCED AND BURNED, A BOILER HAVING HEAR EXCHANGE SURFACE IN A NUMBER OF PASSAGEWAYS AND DISPOSED TO HAVE THE PASSAGEWAYS AND OVER IN THE FURNACE PASS THROUGH THE PASSAGEWAYS AND OVER THIS SURFACE TO OBSORD HEAT FROM THE GASES TO GENERATE STEAM, MEANS FOR SUPPLYING LIQUID OF A PREDENTERMINED ECNCENTRATION TO SAID FURNACE, SAID MEANS INCLUDING MULTIPLE EFFECT EVAPORATORS OPERATIVE TO RISE THE CONCENTRATION TO AN INTERMEDIATE DESIRED VALVE AND A DIRECT CONTACT EVAPORATION FACILITY FOR EVAPORATING THE LIQUOR TO ITS FINAL CONCENTRATION AND LOCATED ADJACENT THE COMBUSTION GAS OUTLET OF THE BOILER TO RECEIVE THE COMBUSTION GAS EXITING THERFROM AS THE EVAPORATION MEDIUM, SAID FACILITY INCLUDING A PAIR OF SEPARATE EVAPORATE MEANS DISPOSED ON ABOUT THE OTHER WITH EACH INCLUDING MEAND TO FORM A POOL OF SAID RESIDUAL LIQUID AND WITH THE POOLS BEING SEPARATE, AN EVAPORATOR WHEEL MEANS MOUNTED IN EACH OF THESE MEANS ABOUT A GENERALLY HORIZONTAL AXIS SO THE LOWER POTION IS IMMERSED IN SAID LIQUOR AND THE UPPER PORTION EXTENDS ABOVE SAID LIQUID MEANS FOR ROTATING THE WHEEL MEANS, MEANS FOR DELIVERING PARTIALLY CONCENTRATED LIQUID FROM THE MULTIPLE EFFECT EVAPORATORS TO THE UPPER OF SAID EVAPORATOR MEANS, AN AVERFLOW FOR SAID UPPER EVAPORATOR MEANS OPERATIVE TO CONVEY LIQUID BY GRAVITY FROM THE UPPER TO THE LOWER EVAPORATOR MEANS, MEANS FOR CONVEYING LIQIOR FROM THE LOWER EVAPORATOR MEANS AND INTRODUCING IT INTO THE FURNACE, SEPARATE DUCT MEANS EXTENDING FROM THE OUTLET OF THE BOILER TO EACH OF SAID EVAPORATOR MEANS OPERATIVE ING COMBUSTION GASES THERETO, ADJUSTABLE MEANS OPERATIVE TO CONTROLLABLY PROPORTION THE GAS FLOW TO EACH VEAPORATO MEANS, ADJUSTABLE DAMPER MEANS IN SAID BOILER EFFECTIVE TO CONTROL THE FLOW OF COMBUSTION GASES SO AS TO CONTROLLABLY BYPASS A PORTION OD THE HEAT EXCHANGE SURFACE OF THE BOILER AND ACCORDINGLY CONTROL WITHIN LIMITS THE GAL TEMPERATURE LEAVING THE BOILER, AND SENSING MEANS OPERATIVE TO SENSE CHANGES IN CONCENTRATION OF THE LIQUOR DELIVERED TO THE FURNACE AND CONTROL MEANS REGULATED BY THE SENSING MEANS AND OPERATIVE TO ADJUST SAID DAMPER MEANS SO AS TO MAINTAIN CONCENTRATION AT A DESIRED VALVE.