ANOSHKIN FLUSHING WING Russian patent published in 2013 - IPC E21B31/06 E21B21/00 

FIELD: oil and gas industry.

SUBSTANCE: device includes a hollow housing with a chamfered working end and a magnetic system with a through axial hole. Outer surface of the housing is made in the form of at least one circular cylinder. Axis of the connection thread coincides with axis of outer cylindrical surfaces. Axis of all the rest cylindrical surfaces of internal elements of the housing is offset relative to the above said axis by the value of 1.0 - 3.0 mm to the side that is opposite to the direction by the chamfered part of the housing end, which is maximum protruding in longitudinal direction. Magnetic system includes a hollow steel core with an external cone and a chamfered working cone and a set of sectors made from magnetic stiff material, which is located between the housing and the core. Chamfered working ends of the housing and the core are equipped with a non-magnetic protective flange.

EFFECT: increasing efficiency and service life, and improving reliability.

3 cl, 4 dwg