Other downhole tools, catalog page 82
Centralizer
Centers the work string in the casing — drag-block and bow-spring types
Description
A casing string centering device, usually used to center the work string while running in and pulling out.
Structure
Two types are available:
- Drag-block centralizer: can be connected at any position in the work string by thread. While running in, the spring-expanded drag blocks press against the casing wall to center the string. The drag blocks have high wear resistance and a long service life
- Bow-spring centralizer: can be fixed at any position on the tubing string or on the outside of the drill string. While running in, the bow springs press against the casing wall to center the string. Simple and easy to use, but with lower wear resistance and a shorter service life than the drag-block type
The bow-spring centralizer is installed outside the casing and does not hold internal or external pressure.
