Falling film evaporator of the rotating drum type

Claim 1

A FILM EVAPORATOR FOR LIQUIDS COMPRISING: (A) A HOLLOW EVAPORATOR CHAMBER; (B) A ROLLER DISPOSED WITHIN SAID CHAMBER AND SUPPORTED THEREBY SO AS TO BE ROTATABLE ABOUT ITS LONGITUDINAL AXIS, SAID ROLLER BEING DISPOSED WITH ITS LONGITUDINAL AXIS SUBSTANTIALLY VERTICAL; (C) MEANS FOR INTRODUCING A LIQUID INTO SAID CHAMBER AND ON TO THE SURFACE OF SAID ROLLER SO THAT SAID LIQUID FLOWS DOWNWARD THEREON; (D) AT LEAST ONE CURVED BLADE PIVOTALLY SUPPORTED WITHIN SAID CHAMBER ABOUT AN AXIS PARALLEL TO THE LONGITUDINAL ROTATION AXIS OF SAID ROLLER, SAID BLADE BEING DISPOSED IN ADJACENT SPACED RELATION AND CURVED CONCAVELY TOWARD SAID ROLLER SO AS TO PROVIDE A WEDGE-SHAPED GAP THEREBETWEEN, SAID GAP WIDTH DECREASING IN THE DIRECTION OF ROLLER ROTATION, SAID GAP HAVING A MINIMUM WIDTH WHICH WILL CAUSE THE LIQUID ON THE ROLLER SURFACE TO BECOME ENTRAINED AND CIRCULATE WITHIN SAID GAP AND BE DISTRIBUTED OVER THE ROLLER SURFACE AS SAID ROLLER IS ROTATED AND SAID LIQUID FLOWS DOWNWARD THEREON; (E) MEANS FOR ROTATING SAID ROLLER; (F) SPRING BIASING MEANS CONNECTED TO SAID BLADE FOR ESTABLISHING THE WIDTH AT THE ENTRANCE OPENING OF SAID GAP IN RESPONSE TO THE FORCES CREATED BY A LIQUID IN SAID GAP; AND (G) MEANS FOR COLLECTING THE LIQUID AS IT FLOWS DOWNWARD OFF OF SAID ROLLER, AND REMOVING SAID LIQUID FROM THE EVAPORATOR CHAMBER.