| 摘要 |
A close-tolerance expandable bow spring centralizer 8 having a first expandable collar 10 A coupled to and spaced apart from a second expandable collar 10 B through a plurality of bow springs 30 wherein expandable collars 10 A, 10 B comprise a plurality of slidably coupled links 16 that separate to expand the diameter of the collars 10 A, 10 B, e.g., upon expansion of an expandable pipe string 80 on which the centralizer 8 is received. Expandable bow spring centralizer 8 may grip the expandable pipe string 80 when in the collapsed configuration to eliminate the need for a stop collar. Additionally or alternatively, a fin 32 may be connected to each bow spring 30 , and then connected to one or more adjacent fins 32 upon collapse of the bow springs 30 to form a restraining band 39 that may be ruptured, e.g., upon expansion of the expandable pipe string 80.
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