Patents Assigned to Diamond Plastics Corporation
  • Patent number: 6491066
    Abstract: A method for forming a spigot on a double-walled pipe and spigots formed by this method are described. The outer wall and an intermediate space of a double-walled pipe is removed from one end of the pipe over the desired chamfer length, and a preformed annular resilient bevel is placed around the remaining inner wall. This method is convenient, requires limited materials and tools, provides easy access to a porous intermediate space for sealing, and does not introduce residual stress to the spigot. Furthermore, the properties of the spigot depend primarily upon the properties of the annular resilient bevel, increasing the probability of achieving a high quality and robust seal.
    Type: Grant
    Filed: May 16, 2000
    Date of Patent: December 10, 2002
    Assignee: Diamond Plastics Corporation
    Inventors: John I. Pitman, Ronald R. Bishop, Dennis E. Bauer, Gerald E. Parkinson