Abstract: A method for coating a pipe involves applying a coating material of cellular structured extruded thermoplastic material to the pipe and enclosing it on the outside by an outer covering layer of compact plastic. In an extrusion head, the annular opening for supplying coating material can be adjusted to a desired temperature by a region having coolant channels separated from the annular opening by an annular heat exchange surface. Before being applied to the pipe, the flowable coating material is guided along the heat exchange surface and cooled to a temperature just above the solidification temperature thereof. After the coating material leaves the annular opening, the coating material expands in a controlled manner, widening the outer covering layer depending on the adjusted temperature of the coating material, until the coating material begins to solidify. The outer covering layer surface condition can correspond to or be different from the pipe.

Abstract: A device for joining the end of a helically corrugated metal tube to a connector or a second helically corrugated metal tube includes a back-up ring, pressure ring and a sealing ring. The connector is provided with a conical transition and an expanded diameter. The second helically corrugated tube is provided with a second back-up ring and pressure ring.