| 摘要 |
<p>A double walled spiral tube includes an outer tube (10) which is formed using a coated metal plate (11) possessing a plurality of corrugations (12) to have the configuration of a spiral cylinder, and an inner tube (20) which is placed inside the outer tube (10) and is constituted by a synthetic resin body (21) formed to have the configuration of a straight cylinder. The double walled spiral tube further includes a flexible intermediate member (30) which is fixed to be interposed between the corrugations (12) of the outer tube (10) and the synthetic resin body (21) of the inner tube (20) and is made of synthetic resin, such that the corrugations (12) of the outer tube (10) and the synthetic resin body (21) of the inner tube (20) can expand and contract independently of each other by the medium of the flexible intermediate member (30) made of synthetic resin.</p> |
