Patents Represented by Attorney, Agent or Law Firm Addex, Inc.
  • External thickness control and method
    Patent number: 6739855
    Abstract: A plastic resin extrusion line for the production of blown film includes an external thickness control device that provides a controllable amount of air from an inlet side through an annular region to one or two sets of lips. Barriers that can be manually or automatically controlled are provided in the annular region for localized control of air flow and thus for localized thickness control. The pressure drop across the barriers is significant relative to that in the lips.
    Type: Grant
    Filed: March 15, 2001
    Date of Patent: May 25, 2004
    Assignee: Addex, Inc.
    Inventors: William Randolph, Robert E. Cree