Control system for separation processes

Claim 1

IN A PROCESS FOR SEPARATING IN A SEPARATION ZONE, AN ESSENTIALLY BINARY FEED MIXTURE CONTAINING A SMALL AMOUNT OF A THIRD COMPONENT INTO TWO PRODUCT STREAMS OF SPECIFICATION QUALITY WHEREIN A STREAM COMPRISING SAID THIRD COMPONENT IS TAKEN OVERHEAD FROM SAID ZONE AND IN WHICH THE PROCESS VARIABLES INCLUDE THE RATE OF KETTLE PRODUCT WITHDRAWAL FROM SAID ZONE, THE RATE OF HEAT INTRODUCTION INTO SAID ZONE, AND THE RATE OF SAID-DRAW PRODUCT WITHDRAWL FROM SAID ZONE, THE IMPROVEMENT COMPRISING CONTINOUSLY WITHDRAWING A FIRST SAMPLE STREAM FROM AN UPPER PORTION OF SAID ZONE, ANALYZING SAID FIRST SAMPLE STREAM TO DETERMINE THE CONCENTRATION OF ONE OF THE COMPONENTS OF SAID MIXTURE, ADJUSTING THE RATE OF SIDE-DRAW PRODUCT WITH DRAWAL FROM THE UPPER PORTION OF SAID ZONE SO AS TO MAINTAIN THE COMPOSTION OF SAID FIRST SAMPLE STREAM CONSTANT WITH RESPECT TO THE COMPONENT BEING MEASURED, CONTINOUSLY WITHDRAWING A SECOND SAMPLE STREAM FROM A LOWER PORTION OF SAID ZONE, ANALYZING SAID SECOND SAMPLE STREAM TO DETERMINE THE CONCENTRATION OF THE OTHER COMPONENT OF SAID FEED MIXTURE AND ADJUSTING ANOTHER OF SAID PROCESS VARIABLES SO AS TO MAINTAIN THE COMPOSITION OF SAID SECOND SAMPLE STREAM CONSTANT WITH RESPECT TO THE COMPONENT BEING MEASURED.