Frederic G Hunt

US Patent:

47336293, Mar 29, 1988

Filed:

Nov 19, 1986

Appl. No.:

6/933361

Inventors:

Frederic G. Hunt - Columbus OH
Robert D. McVay - late of Columbus OH

Assignee:

United McGill Corporation - Groveport OH

International Classification:

B63B 524

US Classification:

114357

Abstract:

A thin-walled large diameter spiral plastic tube with interlocking helical seams made from a strip of polyethylene material. The strip of plastic has a thin configuration with edge constructions providing a bead formation along one edge and a groove formation along the opposite edge, which can enable an interlocked helical seam, in the spiral tube. The strip is fed into a special spiral pipe making machine for plastics which winds and interlocks the edges of the strip. Such tubing is used for ducts and pipes and, filled with expanded polystyrene beads can be used very advantageously as flotation devices. The plastic used in the strips is polyethylene, including medium and high density polyethylenes with high molecular weight (HMW).