Fluid analyzer for control system

Claim 1

IN A FLUID SEPARATION SYSTEM COMPRISING A FRACTIONATION COLUMN HAVING A PLURALITY OF VAPOR-LIQUID CONTACTING TRAYS THEREIN, FIRST CONDUIT MEANS COMMUNICATING WITH SAID COLUMN TO INTRODUCE A MIXTURE OF FLUIDS A AND B TO BE SEPARATED, AN ACCUMULATOR, SECOND CONDUIT MEANS COMMUNICATING BETWEEN THE TOP OF SAID COLUMN AND SAID ACCUMULATOR, COOLING MEANS ASSOCIATED WITH SAID SECOND CONDUIT MEANS, THIRD CONDUIT MEANS COMMUNICATING BETWEEN SAID ACCUMULATOR AND AN UPPER REGION OF SAID COLUMN TO RETURN LIQUID TO SAID COLUMN AS REFLUX, FOURTH CONDUIT MEANS COMMUNICATING WITH SAID ACCUMULATOR TO REMOVE AN OVERHEAD PRODUCT, FIFTH CONDUIT MEANS COMMUNICATING WITH THE BOTTOM OF SAID COLUMN TO REMOVE A KETTLE PRODUCT, AND MEANS TO SUPPLY HEAT TO THE LOWER REGION OF SAID COLUMN; A CONTROL SYSTEM COMPRISING MEANS TO MEASSURE THE TEMPERATURE OF LIQUID ON A PRE-SELECTED TRAY IN SAID COLUMN, MEANS TO MEASURE THE PRESSURE OF THE VAPOR ABOVE SAID TRAY, MEANS RESPONSIVE TO SAID TWO MEANS TO MEASURE TO ESTABLISH A SIGNAL REPRESENTATIVE OF THE QUANTITY (P-VB)/(VA-VB) WHERE P IS THE MEASURED PRESSURE OF SAID VAPOR, VB IS THE VAPOR PRESSURE OF FLUID B AT THE MEASURED TEMPERATURE, AND VA IS THE VAPOR PRESSURE OF FLUID A AT THE MEASURED TEMPERATURE, SAID SIGNAL BEING REPRESENTATIVE OF THE MOL FRACTION OF FLUID A ON SAID TRAY, AND MEANS RESPONSIVE TO SAID SIGNAL TO ADJUST THE OPERATION OF SAID COLUMN TO MAINTAIN SAID SIGNAL CONSTANT.