Process for manufacturing flexible tubing capable of withstanding substantial pressures and flexible metal tubing made thereby

Abstract

In accordance with the teachings of the instant invention, techniques for the manufacture of flexible metal tubing and metal tubing made thereby are set forth wherein a plurality of thin walled metal tubes are concentrically formed one about the other and subsequently corrugated to form continuous lengths of flexible metal tubing capable of withstanding substantial pressures. This is achieved in accordance with the teachings of the instant invention by forming an inner component tube from the continuous forming in a lengthwise direction of a metal band into a tube having longitudinal edges which are welded together to form a continuous, longitudinal welded joint. Concurrently, at least one further component tube is formed concentrically about the inner tube by a lengthwise deformation of a second metal band into a second tube having opposed longitudinal edges in close proximity to each other. This second tube is also welded in a longitudinal direction and immediately thereafter, is reduced in diameter through drawing techniques to an appropriate dimensional relationship with the inner tube initially being formed. The resulting structure is subsequently corrugated in the same manner as a single wall structure is corrugated and it has been found that the resulting structural configuration is highly flexible, unexpectantly simple to corrugate and is capable of withstanding pressures equal to or greater than a single thick walled tube designed for a similar purpose.

Dependencies are inferred from the claim text.