ROLLING DRILLING BIT Russian patent published in 2013 - IPC E21B10/18 

FIELD: mining.

SUBSTANCE: bit includes legs with cutters and blowdown channels, which are mounted on them. Check valves consisting of a protective body and a spring-loaded guide are installed in blowdown channels. Check valve is equipped with a tubular element from elastic material. A shutoff member is provided with longitudinal slots on outer surface. Longitudinal slots are closed in their initial position with the tubular element. Lower part of the guide and the tubular element part contacting with it are made in the form of a cone. The part of the tubular element below the conical section is formed with two semi-cylindrical sections. Those sections adjoin each other with their flat faces, which are fixed in initial position with a spring ring. Outlet part of the tubular element is made in the form of a conical flare.

EFFECT: reliable sealing of a nipple cavity due to the fact that the check valve is provided with a specially designed tubular element.

4 cl, 8 dwg