Heat insulated line pipe - with specified plastic foam filling and plastic lining for two concentric metal pipes

摘要

A heat insulated line pipe consists of two concentric pipes between which a heat insulation layer of plastic foam is arranged. Spacers between them are produced from a spiral of synthetic fibre textile material with raised cup-like impressions in two rows, carrying signal wires between them. Pref. the inner pipe (1) is a seam welded alloy steel or copper pipe with a spiral or circular corrugation. The outer pipe (2) is a similar pipe of aluminium or steel, coated with plastic (3), e.g. PE. The heat insulation (4) between them is made of PU foam. The spacers (5) are made of a spiral of synthetic textile strips with two rows of impressions (6) carrying a pair of signal wires (7) between them. The strips are stabilised by thermoplastic or thermosetting impregnation. ADVANTAGE - No cavities or inhomogeneities in the insulation and it can be produced at low cost.