The utility model provides a pair of jar is prepared to polyester thick liquids, including a preparation jar body, its characterized in that be equipped with a PTA feed pipeline, EG feeding person in charge line, a EG feeding by -pass line, an evacuation pipeline on the preparation jar body, the EG feeding is responsible for the line and is passed through the EG feeding pipeline connection arrive in the evacuation pipeline, the end portion of EG feeding by -pass line stretches into the evacuation pipeline, end portion coils into a non - and seals the ring form, just end portion seals with the blind plate welding.