Method and apparatus for centrifugal casting of contact lenses in open molds

Abstract

According to the method of the invention, molds charged with a monomer mixture are arranged into columns with precisely coaxial casting surfaces inside these columns, namely, in tubes of cylindric shape with openings only 0.01 to 0.03 mm larger the diameter of the outer cylindric surface of the mold or the diameter of a hypothetical cylindrical surface circumscribed to any other, preferably a parallel outer surface of the casting mold. The tube with the inserted column of molds is provided with airtight seals at both ends whereas at least one seal is provided with a valve for alternating evacuation and refilling with an inert gas. The invention also provides apparatus by which a complete sequence of required operations including column tilting and rotation is carried out with the tubes charged in this way until the polymerization is completed without transferring the molds from sealed tubes from one apparatus to another or into intermediate magazines.

Dependencies are inferred from the claim text.