METHOD FOR HEAT INSULATION OF TUBES FOR UNDERGROUND LAYING Russian patent published in 2003 - IPC

FIELD: heat insulation of steel tubes, namely forming water proofing envelope on outer heat insulation coating of foamed materials, for example of foamed polyurethane. SUBSTANCE: method comprise steps of placing in form tube with envelope arranged concentrically to tube with gap; filling annular cavity between tube and envelope with heat insulation coating and providing time interval for structuring it; using as envelope reinforced thin-wall tube of sheet steel provided, for example with rigidity ribs and simultaneously applying thin-layer polymeric water proofing coating at process of making tube; making rigidity ribs at increasing closeness of lock joints of pieces of thin-wall steel tubes; applying polymeric water proofing coating by winding on tube belt on base of water proofing polymer. Method allows not to use high-cost thick-wall polymeric envelopes and not to buy equipment for making them. EFFECT: enhanced manufacturability of process, lowered investments. 3 cl, 3 dwg