| 摘要 |
A rod-like insulator (14) is disposed within a metallic tube (2) to form a clearance between the insulator and metallic tube. A coil member (5) encircles the outer circumferential surface of insulator. Insulating powder (15), which fills interior of material tube, is charged into the metallic tube. The insulator is formed of insulating material with thermal conductivity lower than the insulating powder. |
