PURPOSE: To easily obtain a heat insulating pipe by forming an inner pipe and a spacer with a plastic profile material by simultaneous batch extrusion, in case of the heat insulating pipe of double-pipe type with the rib-shaped spacer existing between the inner and outer pipes.
CONSTITUTION: This invention is related to a heat insulating pipe of double-pipe type in which an air heat insulating layer 30 is formed between an inner pipe 12 and an outer pipe 20 by providing a rib-shaped spacer 14 existing between the inner and outer pipes 12 and 20 made by, for instance, plastic of polyethylene, polypropylene, etc. having flexibility. The inner pipe 12 and the spacer 14 are formed by a plastic profile material 1 by simultaneous batch extrusion. As the result, a manufacture process is reduced, and the low-priced heat insulating pipe of double-pipe type, forming the air heat-insulating layer; can be obtained.
OKIAYU RYUICHI
YOSHIDA SHOTARO
HASEGAWA SHOICHI
