Process control by surface tension measurement

Claim 1

APPARATUS FOR CONTROLLING A CHEMICAL REACTION WHICH IS CHARACTERIZED BY CHANGES IN THE SURFACE TENSION OF THE REACTING MASS DURING THE PROGRESS OF THE REACTION COMPRISING MEANS FOR CONTINUOUSLY EXTRACTING A SAMPLE FROM THE REACTING MASS, VESSEL MEANS FOR RECEIVING A SUFFICIENT QUANTITY OF SAID EXTRACTED SAMPLE FROM SAID EXTRACTING MEANS TO MAINTAIN A CONSTANT LEVEL OF CONTINUOUSLY CHANGING AND REPLENISHED EXTRACTED SAMPLE IN SAID VESSEL MEANS THROUGHOUT THE COURSE OF THE REACTION, MEANS FOR FEEDING GAS UNDER PRESSURE INTO SAID VESSEL MEANS AT A PREDETERMINED POINT BELOW THE LEVEL OF THE TOP SURFACE OF SAID QUANTITY OF EXTRACTED SAMPLE TO FORM A PLURALITY OF SUCCESSIVE DISCRETE BUBBLES IN THE LATTER, MEANS FOR SENSING THE MAXIMUM PRESSURE REQUIRED TO FORM EACH OF SAID SUCESSIVE PLURALITY OF DISCRETE GAS BUBBLES, RESPECTIVELY, IN SAID REACTING MASS SAMPLE AS AN INDEX OF THE CHANGING SURFACE TENSION VALUES THEREOF, AND MEANS RESPONSIVE TO THE DIFFERENCE BETWEEN THE SO INDICATED SURFACE TENSION VALUES AND A PREDETERMINED SET VALUE THEREOF AT WHICH THE REACTING MASS IS TO BE MAINTAINED FOR ADDING A SURFACE-ACTIVE INGREDIENT IN RESPONSE TO DEMAND THEREFOR TO THE REACTING MASS IN AMOUNTS SUFFICIENT TO RETURN THE SURFACE TENSION OF THE REACTING MASS SUBSTANTIALLY TO SAID SET VALUE THEREOF.