That ion

Claim 1

A PROCESS FOR THE CONCENTRATION OF AN AQUEOUS SALT SOLUTION, WHICH COMPRISES, CONTINUOUSLY INTRODUCING AN AQUEOUS SALT SOLUTION INTO AN EVAPORATION ZONE, REGULATING THE HEAT SUPPLIED TO SAID EVAPORATION ZONE TO PROVIDE A SUNSTANTIALLY CONSTANT TEMPERATURE THEREIN, EVAPORATION WATER FROM SAID AQUEOUS SALT SOLUTION IN SAID EVAPORATION ZONE SO AS TO PRODUCE A CONCENTRATED SALT SOLUTION, WITHDRAWING EFFLUENT STEAM FROM SAID EVAPORATION ZONE AND CONDENSING SAME SO AS TO PRODUCE A SUBATMOSPHERIC PRESSURE IN SAID EVAPORATION ZONE, CONTINUOUSLY WITH DRAWING SAID CONCENTRATED SALT SOLUTION FROM SAID EVAPORATION ZONE, PRODUCING AN OUTPUT IMPULSE REPRESENTATIVE OF THE CONCENTRATION OF SAID WITHDRAWN CONCENTRATED SALT SOLUTION, AND AUTOMATICALLY CONTROLLING THE ABSOLUTE PRESSURE IN SAID EVAPORATION ZONE BY ADMITTING AIR INTO THE EVAPORATION SYSTEM TO INCREASE THE PRESSURE IN RESPONSE TO VARIATIONS IN SAID OUTPUT IMPULSE SO AS TO PRODUCE A SALT SOLUTION OF PREDETERMINED CONCENTRATION.