DOUBLE WALL HELICAL PIPE, PIPE FORMING METHOD AND STRIP CONFIGURATION FOR FORMING SAID PIPE

摘要

Double wall helical pipe formed from a single metal strip, pipe forming method and configuration of strip for forming such pipe. A metal strip is formed with pipe seam elements and curled into overlapped helical convolutions, and the seam elements are secured together to provide a helical pipe seam. One or both pipe walls may be corrugated.