Method and apparatus for curtain coating

Claim 1

THE METHOD OF CURTAIN COATING MOVING OBJECTS WITH A LIQUID FILM OF COATING MATERIAL WHICH COMPRISES CONTINOUSLY DISCHARGING A COATING MATERIAL IN AN UNBROKEN SUBSTANTIALLY RECTANGULAR VERTICAL CURTAIN OF SUBSTANTIALLY UNIFORM DIMENSIONS AND MANY TIMES WIDER THAN ITS THICKNESS FROM AN ALONGATED POURING HEAD OVER SUBSTANTIALLY THE ENTIRE LENGHT OF SAID HEADED, CONVEYING THE OBJECTS TO BE COATED THROUGH SAID CURTAIN AT A SPEED TO DEPOSIT THE DESIRED COATING THICKNESS THEREON AND TO UNIFORMLY COAT THE UPPER SURFACES OF SAID OBJECTS IN A SINGLE PASSAGE THROUGH SAID COATING CURTAIN WHILE LEAVING THE UNDER SURFACE OF THE OBJECTS TO BE COATED UNSUPPORTED BY CONVEYING MEANS AT THE POINT WHERE SAID OBJECTS PASS THROUGH SAID CURTAIN, RECOVERING THE COATING MATERIAL WHICH IS NOT DEPOSITED ON THE OBJECTS TO BE COATED IN AN OPEN TROUGH BELOW THE OBJECTS BEING COATED, FLOWING THE SO RECOVERED COATING MATERIAL FROM SAID TROUGH INTO A COATING MATERIAL RESERVOIR, CONTINOUSLY PUMPING THE COATING MATERIAL FROM SAID RESERVOIR BACK INTO SAID ELONGATED POURING HEAD AND REGULATING THE PUMPING TO MAINTAIN A SUBSTANTIALLY UNIFORM SUPPLY OF COATING MATERIAL IN SAID POURING HEAD WHEREBY SUBSTANTIAL UNIFORMITY OF SAID CURTAIN IS MAINTAINED THROUGHOUT THE COATING OPERATION.