Patent ID: 7104788

Claim:
An apparatus for cleaning polyester, comprising an at least partially heated rotary tubular furnace to be fed with a mixture of polyester and an alkaline material and for carrying out a saponification reaction in the mixture, one weir disposed within the rotary tubular furnace, which weir at least partly closes an interior space formed by a shell of the rotary tubular furnace, wherein the weir includes at least one through hole and a closure for at least partly closing the through hole to vary the degree of charge of the rotary tubular furnace by varying a damming action of the weir, and wherein the interior space includes at least one orifice formed in the shell of the rotary tubular furnace which connects the interior space to an exterior space surrounding the rotary tubular furnace in a direction perpendicular to a longitudinal axis of the rotary tubular furnace.