Abstract: An improved apparatus for producing a flexible plastic corrugated tubing includes a pair of relatively short, slender rotating mandrels extending substantially parallel to one another and separated along a vertical plane and around which a continuous ribbon of molten plastic is spirally wrapped to form the tubing. In another embodiment, a plurality of elongated rollers spaced apart axially form a tunnel therebetween through which the tubing is directed from the mandrel at least one of the rollers being rotatably driven to drive the tubing through the tunnel.

Abstract: An apparatus for making helically wound and helically ribbed plastic tubing, comprising: means for extruding a plastic strip having a longitudinal rib; winding means for helically winding the strip about an axis into a tube with one edge of each convolution overlapping and heat bonded to an edge of a preceding convolution and with the rib of the exterior of the tube, the winding means comprising four cantilevered rolls uniformly circumferentially spaced apart around and extending in the direction of the axis and canted relative to the axis at acute angles, opposite rolls being oppositely canted; and means for driving the rolls. The apparatus further includes means for applying a coolant to the tube externally and internally thereof to cool the plastic material after the convolutions of the tube have been heat bonded together.