PURPOSE: To obtain a polyester in good efficiency by preventing the capacity of vacuum generator from being decreased, by inserting, in a demountable manner, a cylindrical collector having a number of small holes and packed with a packing between a condenser for condensing a distillate and a vacuum generator.
CONSTITUTION: A collector 8 comprising a cylindrical vessel constructed of a smaller-diameter part 10 on the upstream side and a larger-diameter part 11 on the downstream side, having a number of small holes 12 on the entire surface and packed with a packing 14 such as Raschig rings or Paul rings is inserted in a demountable manner into a vacuum suction pipe 6 or 6' between a condenser 3 for condensing a distillate and a vacuum generator 7. A glycol vapor containing an oligomer and distilled from the polymerization reactor 1 is led through a distillate pipe 3 to condenser 3 and is condensed. Part of the condensate is sent through a condensate pipe 5 and stored in a receiver 4. Oligomer not collected in condenser 3 is led through suction pipe 6 to collector 8 and is completely collected by adhesion to the inside and outside surfaces of packing 14.
SAEKI TOYOKI
NAGAKI HIDEYUKI
