Caustic recovery unit with specific gravity flow control means

Claim 1

A RECOVERY UNIT FOR CONCENTRATING A SOLUTION COMPRISING AN AFTER COOLER, A FIRST TANK, A SECOND TANK, A FIRST HEATER, A SECOND HEATER, MEANS CONNECTING A DILUTED SOLUTION THROUGH SAID AFTER COOLER TO SAID FIRST TANK, A VALVE RESPONSIVE TO THE LEVEL OF LIQUID IN SAID FIRST TANK CONTROLLING THE FLOW OF LIQUID THEREINTO, A CONCENTRATE PUMP PUMPING LIQUID SELECTIVELY THROUGH A VALVE OF SAID SECOND TANK WHEN THE LIQUID LEVEL THEREIN IS BELOW A PREDETERMINED VALVE AND PUMPING LIQUID THROUGH SAID FIRST HEATER WHEN THE LIQUID IN SAID SECOND IS ABOVE PREDETERMINED VALVE, SAID LIQUID FLOWING FROM SAID FIRST HEATER THROUGH A SPRAY MEANS TO SAID FIRST TANK, MEANS CONNECTING LIQUID FROM SAID SECOND TANK TO A SPECIFIC GRAVITY VALVE, SAID SPECIFIC GRAVITY VALVE SELECTIVELY CONNECTING SAID CONCENTRATED LIQUID TO SAID AFTER COOLER AND THENCE TO A STORAGE TANK WHEN THE SPECIFI GRAVITY FO SAID CONCENTRATED LIQUID IS ABOVE A CERTAIN VALUE AND CONNNECTING SAID LIQUID FROM SAID SECOND TANK TO FLOW THROUGH SAID SECOND HEATER WHEN THE SPECIFIC GRAVITY OF SAID CONCENTRATED LIQUID IS BELOW A CERTAIN VALUE, EXTERNAL HEATING MEANS FOR SAID SECOND TANK, AND MEANS IN SAID FIRST TANK TO REMOVE CONDENSED VAPORS FROM SAID UNIT.