Importance

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Abstract

A method and apparatus are provided for producing pre-insulated pipes, which can be configured both for producing corrugated pipes and smooth pipes. The new method does not require a film to enclose expanding foam insulation around an inner pipe prior to it being enclosed by a jacket casing. Instead, a jacket casing is extruded around the inner pipe, the inner pipe and casing fed into a vacuum unit and the inside of the jacket casing is surface treated to ensure adherence between layers just after it exits the extruder and before it is fed into a vacuum unit. Inside the vacuum unit, a dispenser dispenses liquid expanding insulation material (such as polyurethane) in the space between the jacket casing and the inner pipe.

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First Claim