Method and apparatus for controlling tandem extruder

Abstract

Abstract PURPOSE:To unnecessitate a gear pump, by a method wherein the rotating speed of the second extruder is set to be constant, and the rotating speed of the first extruder is so controlled as to make constant the material pressure difference between the charging side and ejecting side of the second extruder, in a tandem extruder for a molten resin. CONSTITUTION:A die 22 is fitted to a tip part of the second extruder 16 through a filter 21, and a molten resin supplied from a ejecting port of the first extruder 11 through a connecting pipe 23 is extruded. The rotating speed N2 of a screw for the second extruder 16 is controlled to be constant by a loop comprised of a speed detector 19, a speed controller 20 and a driving motor 18. The pressure difference P1-P2 between the charging side and the ejecting side of the second extruder 16 is detected by pressure difference detectors 24, 25 and a comparing calculator 26, and a pressure controller 28 performs a cascading action on a screw rotating speed controlling system for the first extruder 11 which system is comprised of a speed detector 14, a controller 15 and a driving motor 13 so that the pressure difference becomes a set point 27, whereby the pressure difference P1-P2 is controlled to be constant. Accordingly, clogging of the filter can be automatically compensated for without using any gear pump.

Inventors

• 👤 Katsuhiro Iguchi
• 👤 勝啓 井口
• 👤 Kenji Nozawa
• 👤 野沢　憲司

Bibliographic Details