VACUUM DEGREE CONTROL DEVICE AND METHOD BY ELECTROMOTIVE VALVE OF PUSHER

摘要

PROBLEM TO BE SOLVED: To elongate service life of a filter in an oligomer collecting tank by maintaining vacuum degree in a vent pipe constant.SOLUTION: The vacuum degree control device and method by an electromotive valve of a pusher are configured so that: a vacuum degree meter (31) and an electromotive valve (30) are disposed on a vent pipe (6) between a pusher (3) and an oligomer collecting tank (20); a vacuum degree detection value (PV) in the vent pipe (6) is compared to a vacuum degree set value (SV); and the difference (▵α) is fed back to valve opening/closing control of the electromotive valve (30) for controlling the electromotive valve (30). Thereby vacuum degree stabilizes and replacement timing of a filter (21) is elongated.