EXPANDER Russian patent published in 2015 - IPC E21B7/28 

FIELD: mining.

SUBSTANCE: expander comprises the housing, piston with a rod, hingedly installed vanes, reinforced with hard alloy, thrusters, bushing, upper support with spheric boring and nut. The bushing is fitted with keys and sphere installed in spheric boring of the upper support, fitted with longitudinal slots facing towards bushing keys. The piston with the rod is installed in the axial channel of the housing enclosed from below with the nut, with longitudinal slots for vanes installed in them hingedly on axles. The bottom end of the hollow rod is fitted with the bottom bearing surface with longitudinal slots, where on axles the thrusters connected to vanes through hinged axles are placed. The housing cavity under the ring-type piston has the constant hydraulic connection through radial holes in the housing body of the hollow rod with its axial channel, and the cavity above it is connected by a bypass hole with the well cavity.

EFFECT: possibility of expansion of a well bore below the casing shoe at any depth, the possibility of monitoring of radial load on a rock-breaking tool, the possibility of wash-over of a well bore, the possibility of returning of the rock-breaking tool into transport position after the pressure resection in the axial channel of the drill pipe string.

2 dwg