Closed circuit distillant feed with indirect heat exchange condensation

Claim 1

A PROCESS OF OPERATING A VAPOR RECOMPRESSION SYSTEM WHEREIN COMPRESSED VAPORS EXTRACTED FROM A LIQUID FEED MATERIAL ARE CIRCULATED AT A CONDENSING PRESSURE INSIDE THE TUBES OF A GENERALLY HORIZONTAL-TUBE HEAT EXCHANGER, THE TUBES BEING DISPOSED IN THE VAPOR SPACE OF A VAPORIZING CHAMBER, INCLUDING THE STEPS OF DISTRIBUTING A PREHEATED FEED MATERIAL TO BE CONCENTRATED GENERALLY DOWNWARDLY OVER SAID TUBES, SUPPLYING PREHEATED FEED MATERIAL FOR SAID DISTRIBUTING STEP, WITHDRAWING THE VAPORS EVOLVED FROM SAID FEED MATERIAL, COMPRESSING SAID WITHDRAWN VAPORS, CIRCULATING THE COMPRESSED VAPORS THROUGH THE HEAT EXCHANGER TUBES IN CONDENSING INDIRECT HEAT EXCHANGE RELATION TO THE FEED MATERIAL, RECOVERING THE CONDENSATE FORMED IN SAID CIRCULATING STEP, COLLECTING THE CONCENTRATED MATERIAL REMAINING AFTER THE VAPORS HAVE BEEN WITHDRAWN, WITHDRAWING THE CONCENTRATE FROM THE POINT OF COLLECTION, DIRECTING A PORTION OF THE WITHDRAWN CONCENTRATE THROUGH A VALVE AND METERING DEVICE TO DISCHARGE SOME OF THE COLLECTED CONCENTRATE AND TO CONTROL THE RATE OF DISCHARGE SO AS TO MAINTAIN A DESIRED CONCENTRATION OF THE COLLECTED CONCENTRATED MATERIAL, AND RECIRCULATING THE REMAINING PORTION OF THE COLLECTED CONCENTRATED MATERIAL INTO FEED FOR USE IN SAID DISTRIBUTING STEP.