| 摘要 |
<p>The specification describes a dual-wall drill pipe section comprising an outer pipe member having a box end formed with an internal thread and a pin end formed with an external thread for engagement with the box end of another outer pipe member, the bore of one of the ends of the outer pipe member is formed with a shoulder and a circumferential, inwardly facing groove axially spaced from the shoulder, an inner pipe member concentrically disposed within the outer pipe member so as to define an annular passage between the inner and outer pipe members, spacer members connected to each end of the inner pipe member and disposed in the annular passage for maintaining concentricity between the inner end outer pipe members, the spacer members at one end of the inner pipe being formed with a shoulder for abutting engagement with the shoulder of the outer pipe member so as to axially locate and support the inner pipe member within the outer pipe member, and at least one spring member connected to the inner pipe member and having a portion engageable with the groove of the outer pipe member for resiliently and frictionally retaining the inner pipe member within the outer pipe member during storage and handling of an assembled pipe section.</p> |
