DRILLING STRING SEALING DEVICE Russian patent published in 2006 - IPC E21B33/03 

FIELD: oil and gas industry, particularly to construct and repair wells to provide work exciting under reverse drilling mud circulation.

SUBSTANCE: device comprises preventer and body with packing members for pipe string plugging. To seal drilling string device body is fastened to drilling pipe comprising lock - upper and lower clutches. The body is installed inside all-purpose preventer and is sealed with packing member of all-purpose preventer and may be fastened to drilling string by means of lock. Annular space between the body and drilling pipe is sealed with packing body members installed on thrust ring between upper and lower pressure bushes fastened by means of lock.

EFFECT: simplified production and operation, provision of reverse drilling mud circulation without well head connections modification.

2 dwg