DOWNHOLE INSTRUMENT CENTERING DEVICE Russian patent published in 2006 - IPC E21B47/00 E21B17/10 

FIELD: well development survey, particularly downhole instruments used in cased wells.

SUBSTANCE: method involves coupling arch-shaped springs in pairs uniformly arranged along movable bush perimeter. Springs of each pair are connected to opposite movable bush ends and offset at least 600 mm one from another. Annular groove is formed on inner movable bush surface. Split ring is arranged in the annular groove. Through slots for rotary roller securing are formed on sliding surface of arc-shaped springs.

EFFECT: increased operational reliability of device usage in cased wells, increased efficiency of downhole instrument centering and reduced noise caused by downhole instrument movement along pipe string.

2 cl, 4 dwg