Heat insulated pipe and method of its manufacturing

摘要

The pipe has an inner pipe made of plastic or metal, and an outer casing made of plastic, where a thermal insulation layer (16) made of plastic foam is provided between the inner pipe and the outer pipe. The thermal insulation layer has an annular- or screw shaped recess in a surface of the outer casing. The recess of the thermal insulation layer has a half-wave i.e. cosine half wave, shape in longitudinal section, where the cosine half wave and/or a catenary curve are converged by a trapezium shape. An independent claim is also included for a method for manufacturing a heat insulated pipe.