| 摘要 |
A centraliser has a longitudinal axis and comprises first and second opposing end collars 51, 52 positioned around the axis of the centralizer, and a plurality of spring bows 53-56 extending from the first end collar 51 via a generally convex curved portion to the second end collar 52. A radial distance from an outwardly facing portion of the first end collar to the axis is greater than a radial distance 60 from a first outwardly facing portion of a spring bow of the plurality of spring bows 53-56, at a longitudinal axial position where the spring bow extends from the first end collar 51, to the axis, and less than a radial distance from a second outwardly facing portion of the spring bow, at a longitudinal axial position between the first end collar 51 and the second end collar 52 that is farthest from the axis, to the axis. The outward radial distance of the collars 51, 52 may be extended by the use of protrusions such as bows 60a-60d. The outward facing portion of the first end collar 51 may have a shape to direct fluid flow into a turbulent flow. |
