Double-walled, flexible hose

In a hose having an inside wall surface spaced from an outside wall surface to provide a flexible double wall hose with a helical reinforcement with axial spacing between the turns being positioned in a cavity between the walls, the improvement comprising the hose being constructed of a helically extending member having a cross-sectional profile containing a center part with an inside surface extending parallel to an outside surface, the center part having a thickness between said inside and outside surfaces corresponding to the thickness of the double wall of the hose, said outside surface having a first extension and the inside surface having a second extension, said first and second extensions proceeding in opposite directions from the center part and forming extended surfaces for the inside and outside surfaces, said member being helically wound into a hose with the first and second extensions engaging opposite turns of the member to form a continuously smooth outside wall surface and a continuously smooth inside wall surface, said center part and the extensions providing separate cavities when the turns of the member are secured together to form the hose, said reinforcement being disposed in one of the cavities and the helical member being composed of a soft material while the reinforcement comprises a material harder than the material of the helical member and less flexible.