Falling film evaporator for stripping latex solutions

Claim 1

IN COMBINATION, A COLUMN HAVING AN UPPER LIQUID INLET AND A LOWER OUTLET MEANS, SAID COLUMN INCLUDING A CYLINDRICAL CASING WALL WITHIN WHICH IS PROVIDED A STAGED SERIES OF VERTICALLY SUPERPOSED GENERALLY TRANSVERSE, UPWARDLY FACING, OPEN-END, BOX-LIKE TRAYS HAVING CORRESPONDING LATERAL EDGES SPACED FROM THE WALL DEFINING A PAIR OF PARALLEL VERTICAL PLANES AND PROVIDING AN ANNULAR SPACE BETWEEN THE EDGES OF SAID TRAYS AND SAID WALL, ADJACENT PAIRS OF TRAYS CONVERGING WITH OPEN ENDS FACING ONE AWAY FROM ANOTHER, THE LOWER TRAY OF A PAIR EXTENDING BEYOND THE POINT OF CONVERGENCE AND THE UPPER TRAY WITH ITS OPEN END TERMINATING SHORT OF THE POINT OF CONVERGENCE SO THAT LIQUID CAN FALL INTO AND CASCADE DOWNWARDLY IN A GENERALLY VERTICAL ZIG-ZAG PATH FROM ONE TRAY TO ANOTHER, A PLURALITY OF CAPACITANCE PROBES LOCATED AT DIFFERENT LEVELS WITHIN THE COLUMN WALLS AND EXTENDING INTO SAID ANNULAR SPACE SUBSTANTIALLY PERPENDUCULAR TO THE PARALLEL PLANES, A FOAM CORRECTIVE DEVICE, SAID CAPACITANCE PROBES BEING OPERATIVELY CONNECTED TO SAID FOAM CORRECTIVE DEVICE TO OPERATE SAID DEVICE WHEN A CHANGE OF CAPACITANCE IS MEASURED, EACH OF SAID PROBES HAVING A SENSITIVITY RANGE OF UP TO ABOUT TEN MICROMICROFARADS AND A SURFACE AREA OF BETWEEN TWELVE AND EIGHTY SQUARE INCHES AND A DIAMETER RANGING FROM ABOUT ONE-HALF INCH TO ABOUT ONE INCH AND A LENGTH TO DIAMETER RATIO GREATER THAN TWELVE.