Waste sulfite liquor recovery

Claim 1

IN A SULPHITE PULP PLANT COMPRISING A STEAM GENERATOR, STEAM CONDUIT MEANS FOR CONDUCTING STEAM FROM THE STEAM GENERATOR, A DIGESTER ADAPTED TO RECEIVE A FIBROUS SUBSTANCE, SULPHITE COOKING LIQUOR AND STEAM FROM THE STEAM GENERATOR, MEANS FOR BLOWING-DOWN SAID DIGESTER, SEPARATING MEANS ADAPTED TO SEPARATE FIBROUS SUBSTANCE AND COOKING LIQUOR, MEANS FOR CONDUCTING THE MIXTURE BLOWN-DOWN FROM THE DIGESTER TO THE SEPARATING MEANS, A PLURALITY OF EVAPORATORS EACH HAVING AN EVAPORATING ZONE, CONCENTRATE CONDUIT MEANS FOR CONNECTING SAID EVAPORATORS IN SERIES SO THAT CONCENTRATE IS CONDUCTED FROM ONE EVAPORATOR TO THE EVAPORATING ZONE OF THE NEXT SUCCEEDING EVAPORATOR, A CONDENSER COMMUNICATING WITH EACH EVAPORATOR SO AS TO RECEIVE CONDENSIBLE MEDIUM THEREFROM, SAID CONDENSERS BEING ADAPTED FOR THE PASSAGE OF A CONDENSING MEDIUM AND A CONDENSIBLE MEDIUM IN INDIRECT HEAT EXCHANGE RELATIONSHIP WITH ONE ANOTHER, MEANS CONNECTING SAID CONDENSERS IN SERIES SO AS TO CONDUCT CONDENSING MEDIUM AFTER PASSAGE THEREOF IN SAID HEAT EXCHANGE RELATIONSHIP WITH SAID CONDENSIBLE MEDIUM IN ONE CONDENSER FROM THE ONE CONDENSER TO THE NEXT SUCCEEDING CONDENSER, VACUUM PRODUCING MEANS COOPERATING WITH EACH OF THE EVAPORATORS AND CONDENSERS TO MAINTAIN THE SAME UNDER VACUUM AND EVAPORATE THE LIQUOR CONDUCTED TO SAID EVAPORATORS, WASTE SULPHITE LIQUOR CONDUCTING MEANS IN COMMUNICATION WITH SAID SEPARATING MEANS SO AS TO RECEIVE SEPARATED LIQUOR THEREFROM AND IN COMMUNICATION WITH THE EVAPORATING ZONE OF THE FIRST OF A SERIES OF EVAPORATORS TO CONDUCT SAID LIQUOR THERETO, CONCENTRATE RECEIVING MEANS, MEANS IN COMMUNICATION WITH THE LAST OF SAID SERIES OF EVAPORATORS AND WITH THE CONCENTRATE RECEIVING MEANS, CONCENTRATE CONDUCTING MEANS IN COMMUNICATION WITH THE CONCENTRATE RECEIVING MEANS AND THE FIRST OF A SERIES OF SAID CONDENSERS SO AS TO CONDUCT THE CONCENTRATE TO SAID FIRST CONDENSER FOR USE AS A CONDENSING MEDIUM THEREIN, AND A USED CONCENTRATE CONDUIT IN COMMUNICATION WITH THE LAST OF SAID SERIES OF CONDENSERS AND THE FIRST OF SAID SERIES OF EVAPORATORS SO AS TO RECEIVE SAID USED CONCENTRATE AFTER USE THEREOF AS A CONDENSING MEDIUM IN SAID LAST CONDENSER AND TO CONDUCT IT TO THE EVAPORATING ZONE OF SAID FIRST EVAPORATOR.