METHOD FOR SIMULTANEOUS CONTROL OF MULTIPLE ACCUMULATORS

摘要

A method for cascade, closed loop control of multiple operating parameters for an extrusion blow molding machine having multiple accumulators is disclosed. The method provides closed loop control of the ram back pressure during refill, along with the closed loop adjustment of the pressure set points for "slave" accumulators based on a comparison of ram positions with that of a "master" accumulator. For systems that supply each accumulator with a separate extruder, the rotational speed of the extruder screw is the controlled operating parameter during refill. With respect to extrusion of the parisons, there is closed loop control of the ram velocity in conjunction with adjustment of the velocity set points for the slave accumulators based on a comparison of ram positions with that of the master accumulator.