Production of tubular body comprising two or more layers of helically bended strips

A process for the manufacture of an elongated, multilayered tubular body comprising an elongated, tubular inner hollow core, an elongated, tubular inner casing and an elongated, tubular outer casing, the inner casing surrounding the hollow core, the outer casing surrounding the inner casing, the outer casing comprising at least two layers, each layer consisting of one or more longitudinally preformed, flat elongated metal strips, the preforming of the strips such that the strips have been bent helically in such a way that the consecutive windings of the helix or helices touch or almost touch to each other, each strip in one layer overlapping with other strips in other layers, the layers in the outer casing being bound to each other by an adhesive,

• the process comprising providing an elongated inner casing, providing one or more first flat elongated metal strips, plastically preforming the one or more first metal strips in a bending process to obtain one or more helices and applying the one or more preformed first metal strips onto the inner casing to form the first layer of the outer casing, providing and applying adhesive, providing one or more second flat, elongated metal strips, plastically preforming the one or more second metal strips in a bending process to obtain one or more helices and applying the preformed one or more second metal strips on the first layer of the outer casing to form the second layer of the outer casing, optionally followed by the further provision and application of one or more additional layers of adhesive and preformed flat, elongated metal strips, especially a process in which the provision of the inner casing, the provision of the first and second metal strips and optionally any further metal strips, the bending of the first and second and optionally any further metal strips and the application of the adhesive is carried out in a simultaneous way.