CHECK VALVE FOR DRILL STRING Russian patent published in 2019 - IPC E21B34/10 E21B21/10 

FIELD: mining.

SUBSTANCE: invention relates to mining and can be used as a check valve for a drill string. Valve consists of nipple and adapter jointed by common thread and having axial channel for pump supply of hydroabrasive medium, installed between them seat with seal from elastomer and shut-off element contacting with seat and equipped with spring, pressing shut-off element to seat. Locking element is made in the form of a hollow plunger with a central channel, the outlet of which is hermetically plugged by front and bottom cowlings. Bottom cowling has a working face tightly contacting with the plunger seat. Openings for hydroabrasive medium are made in plunger wall. Seal of elastomer is limited in direction of valve outlet by part of seat sliding surface. Spring is arranged in annular cavity between adapter, Locking element and seat. Annular cavity with spring arranged therein is configured to communicate with inlet of valve axial channel. Inlet part of the central channel of the plunger along the flow of the hydroabrasive medium is made in form of adjoining channels: confusor, cylindrical and diffusion. Radial circulating orifices are made in diffusion channel path wall to communicate central channel of plunger with annular cavity between adapter, plunger and seat with spring arranged therein.

EFFECT: increasing service life and reliability of valve.

4 cl, 2 dwg