Device to increase the residence time of liquid in thin film apparatus

Claim 1

IN THIN FILM APPARATUS OF THE TYPE INCORPORTING A ROTOR STRUCTURE HAVING BLADE ELEMENTS BY WHICH FLUENT MATERIAL FED TO THE APPARATUS IS SPREAD IN THIN LAYER FORM OVER A SURROUNDING STATIONARY SURFACE WITHIN THE APPARATUS WHILE BEING CAUSED BY GRAVITY TO FLOW DOWNSTREAM ALONG SAID SURFACE FOR PROCESSING TREATMENT, THE IMPROVEMENT WHICH COMPRISES ANNULAR DAMMING MEANS FIXED AT THE DOWNSTREAM END OF SAID SURFACE AND EXTENDING INWARDLY THEREAT FOR CAUSING AN INWARD OVERFLOWING OF SAID FLUENT MATERIAL FROM SAID SURFACE THAT IS OPPOSED BY CENTRIFUGAL FORCE EXERTED BY THE BLADE ELEMENTS OF SAID ROTOR STRUCTURE TO IMPOSE ON THE DOWNSTREAM FLOW OF SAID FLUENT MATERIAL ALONG SAID SURFACE THE FORM OF A ROTATIONAL PARABOLOID REACHING UPSTREAM FROM SAID DAMMING MEANS AND THEREBY INCREASE THE RESIDENCE TIME OF SAID FLUENT MATERIAL ON SAID SURFACE, ALL PORTIONS OF SAID APPARATUS AND OF SAID ROTOR STRUCTURE DOWNSTREAM OF SAID DAMMING MEANS BEING FREE OF ANY FLOW FORCING BLADE ELEMENTS AND BEING FORMED FOR ACCOMMODATING THE INWARD OVERFLOWING OF SAID FLUENT MATERIAL FOR CONTINUING DOWNSTREAM FLOW AT A SUFFICIENT RATE TO AVOID ANY RETROGRESSIVE INFLUENCE FROM SAID CONTINUING DOWNSTREAM FLOW ON THE INWARD OVERFLOWING CAUSED BY SAID DAMMING MEANS.