| 摘要 |
A method of making insulating ducts especially for the flow of low-temperature fluids such as liquefied gases, comprises forming an insulating layer between inner and outer tubes piercing the insulating layer from the exterior and anchoring holders at their inner ends in the holes pierced in the insulation for spacing the two tubes apart. The piercing is by an open flame or a heated rod or piston, preferably using a template for the appropriate spacing of the holes through which the holders pass. |
