Patents Assigned to Protens, Inc.
  • Patent number: 7140859
    Abstract: This specification describes an apparatus for carrying out a method of making a multi-walled pipe in the shape of a tube having a helical configuration. The apparatus is made up of an extruder with multiple dies. These multiple dies include at least two concentric arcuate dies that are radially spaced apart and a plurality of relatively straight dies that radially connect the concentric arcuate dies. The apparatus includes means for cooling the extrudate to solidify it into a usable condition. Means are provided to cause the multi-wall pipe to have a helical configuration, that is, apparatus is provided that arranges the pipe as a whole into a structure that has a circumferential component and a longitudinal component to its orientation; e.g. a helix. The longitudinal orientation is accomplished by providing apparatus that causes the pipe to proceed downstream in the direction of its longitudinal axis. In one embodiment of this invention, the extrudate is pulled longitudinally down stream.
    Type: Grant
    Filed: June 17, 2005
    Date of Patent: November 28, 2006
    Assignee: Protens, Inc.
    Inventor: F. John Herrington