| 摘要 |
A ventilation tube (20, 120, 220) is disclosed. The ventilation tube (20, 120, 220) comprises an inner wall (22, 122, 222) that defines a fluid passageway for 5 ventilation gases, an outer wall (24,124,224) that surrounds the inner wall (22, 122, 222) and has a greater thickness than the inner wall (22, 122, 222), a helical separator member (26, 126, 226) interposed between the inner and outer walls (22, 122, 222, 24, 124, 224) so as to define an insulation chamber between the inner and outer walls (22, 122, 222, 24, 124, 224), and a heating element (28, 128, 228) disposed within the insulation chamber. |
