SLIT-FORMING DEVICE Russian patent published in 2019 - IPC E21C37/00 E21B43/26 

FIELD: mining.

SUBSTANCE: invention relates to mining and can be used for drilling of wells or bore pits with cutting of initiating slit in rock mass for further hydraulic fracturing with the purpose of its softening or degassing. Slit-forming device includes a housing in which a longitudinal window is made and a knife is installed with possibility of its cutting part outlet from the longitudinal window of the housing, as well as arranged a piston with possibility of axial movement and interaction with knife. In the piston cavity there is a pressure valve, between the housing and the piston there is a return spring, and in the head part of the housing there is a drilling bit and a check valve. Under-valve cavity of check valve is connected by channel with under-piston cavity. Piston axis is offset relative to housing axis.

EFFECT: reduction of metal consumption of slit-forming device, exclusion of pusher contact with rock mass and friction of knife at its exit from housing.

3 cl, 3 dwg