EXPANDER Russian patent published in 2013 - IPC E21B10/26 

FIELD: mining.

SUBSTANCE: expander comprises a crown with washing slots on an outer surface, a guide rod rigidly connected to it and comprising a head, and a circular attachment and elastic rings installed on it and placed at both ends of the attachment. When a double drilling string is used for supply of the washing liquid and a cleaning agent with lower specific weight, the crown body is made with radial channels, output ends of which are placed in its washing slots and are directed towards the well head, at the same time radial channels are connected to the cavity of the drilling string serving to supply the cleaning agent with the lower specific weight.

EFFECT: increased efficiency of expander operation, improved operation of its cleaning system.

2 cl, 3 dwg