Patents Assigned to Johnston Construction Limited
  • Lining or relining of tunnels
    Patent number: 4347018
    Abstract: A method of lining or relining a tunnel comprises the steps of deforming a collar for insertion into the tunnel, reforming the collar to locate it in the tunnel, overlapping the edges of a pipe having a single longitudinal split to reduce its cross-sectional area for insertion into the tunnel, re-aligning the edges and expanding the pipe in the tunnel for engagement with the sleeve, and securing the edges together to retain the pipe in its expanded form.
    Type: Grant
    Filed: August 5, 1980
    Date of Patent: August 31, 1982
    Assignees: Johnston Construction Limited, Johnston Pipes Limited
    Inventors: Noel T. Wrightson, Russell D. Currie