| 摘要 |
A heat insulated, flexible pipe is produced by drawing onto a thinwalled metal pipe (2) an insulating hose (8) of netted polyethylene foam, which is a soft material having closed cells and being water and heat resistant up to normal operation temperature. Thereafter the metal pipe (2) is overheated by means of electricity or a heating medium until the inner surface of the foam hose (8) gets welded to the outside of the metal pipe (2). The foam insulated pipe may be provided with a smooth or corrugated outer mantle tube (20), which when in known manner consisting of polyethylene, may get bonded to the foam tube by extrusion of the mantle tube directly onto the foam hose. In case of an escape later occuring in the metal pipe such an escape will be sealed in advance because of the welded on foam material and the closed cells thereof. |
