Multi-stage evaporating apparatus

Claim 1

EVAPORATING APPARATUS COMPRISED OF A PLURALITY OF EVAPORATING STAGES DESIGNED TO OPERATE AT A PLURALITY OF PRESSURES INCLUDING: (A) MEANS TO DELIVER UNEVAPORATED LIQUID FROM EACH STAGE, EXCEPT THE LOWEST PRESSURE ASTAGE, TO A LOWER PRESSURE EVAPORATING STAGE; (B) MEANS TO TRANSFER VAPOR PORDUCTS FROM EACH STAGE, EXCEPT THE LOWEST PRESSURE STAGE, TO A LOWER PRESSURE EVAPORATING STAGE; (C) A CONDENSER; (D) MEANS TO DELIVER TO SAID CONDENSER A LIQUID FEED, SAID LIQUID FEED TO BE HEATED THEREIN, AND VAPOR PRODUCTS OF THE LOWEST PRESSURE STAGE OF THE APPARATUS, SAID PRODUCTS TO BE CONDENSED THEREIN; (E) A FIRST COOLER; (F) MEANS TO DELIVER TO SAID FIRST COOLER CONDENSATE, FROM A HIGH PRESSURE EVAPORATING STAGE, SAID CONDENSATE TO BE COOLED THEREIN, AND A FIRST PORTION OF THE LIQUID FEED, SAID PORTION TO BE HEATED THEREIN; (G) A SECOND COOLER; (H) MEANS TO DELIVER TO SAID SECOND COOLER CONDENSATE, FROM A LOW PRESSURE EVAPORATING STAGE, SAID CONDENSATE TO BE COOLED THEREIN, AND A SECOND PORTION OF THE LIQUID FEED, SAID PORTION TO BE HEATED THEREIN; (I) HEAT EXCHANGE MEANS IN CONTACT WITH VAPOR PRODUCTS OF THE VARIOUS STAGES OF THE APPARATUS; (J) MEANS TO DELIVER A THIRD PORTION OF THE LIQUID FEED TO SAID HEAT EXCHANGE MEANS, SAID PORTION TO BE HEATED THEREIN; (K) MEANS TO DELIVER THE THIRD PORTION OF THE LIQUID FEED FROM SAID HEAT EXCHANGE MEANS TO THE HIGHEST PRESSURE STAGE OF THE APPARATUS; (L) MEANS TO COMBINE THE SECOND PORTION OF THE LIQUID FEED WITH UNEVAPORATED LIQUID PRIOR TO ITS DELIVERY TO A LOWER PRESSURE STAGE OF THE APPARATUS; AND (M) MEANS TO COMBINE THE FIRST PORTION OF THE LIQUID FEED WITH UNEVAPORATED LIQUID PRIOR TO ITS DELIVERY TO AN INTERMIDIATE PRESSURE STAGE OF THE APPARATUS.