SLIDING COUPLING WITH INVERTING BALL SEAT Russian patent published in 2017 - IPC E21B34/14 E21B43/26 

FIELD: mining.

SUBSTANCE: invention relates to stepped formation hydraulic fracturing means. Sliding coupling is opened by a dropped ball. Coupling has a seat installed in a housing, and the seat has segments with deviation outwards from each other by a split ring or another deflecting element. First, the seat has an extended state in the sliding coupling, herewith the segments of the seat are expanded outside thrusted to the housing channel. When a ball of the proper diameter is dropped onto the borehole bottom, the ball is engaged with the extended seat. Supplied fluid medium pressure acting on fitted into seat ball, moves the seat into the channel of the inner bushing. Seat is reduced, which increases seat with ball adhesion area. Finally, the seat reaches the collar in the inner bushing, wherein supplied pressure acting on fitted into seat ball, displaces inner bushing in housing to open sliding coupling flow passage opening.

EFFECT: technical result consists in improvement of sliding coupling efficiency, opened by releasing plug.

21 cl, 37 dwg