| 摘要 |
<p>A tube (22) having a cylindrical main body (30) and a thin wall defined by an inner surface (44) and outer surface (46). The tube (22) includes a first segment (32) having a generally constant cylindrical cross section and another segment (34) having a variable cross section containing convolutions to allow for flexing of the tube (22) during installation. The convolutions (40) extend less than the entire circumference of the tube or have tapered side walls (74) which substantially reduce the size of the convolutions (40) as the convolutions (40) extend from one position along the circumference to a second position.</p> |
