| 摘要 |
A method and an apparatus bend a pipe to mitigate internal wrinkling, with particular benefit when bending a lined pipe upon spooling. Bending is performed continuously by advancing the pipe through a bending zone while an internal mandrel is held at the bending zone to resist wrinkling In one variant, the mandrel includes longitudinally-spaced pipe-engaging elements and a tensile link between the elements allows relative movement between the elements. A hold-back connection on one of the elements applies hold-back force to that element to be transmitted to the other element via the tensile link. In another variant, the mandrel includes an elongate pipe-engaging body with a hold-back connection at one end of the body. The body is flexible to bend with the pipe and is shaped to engage an inner surface of the pipe along most of the length of the body. |
