FORMING TUBES FROM STRIP HELICALLY

摘要

The method of forming tubes from strip in which a complementary rib and groove are spaced apart to each extend longitudinally on the strip and oppositely facing on the said strip characterized by guiding the strip into a helical configuration to overlap the edges of the said strip, and pressing together the overlapping parts of the said strip while maintaining a differential pressure in the direction of feed to force the strip together under such differential pressure.