RETURN VALVE FOR DRILLING STRINGS Russian patent published in 2017 - IPC E21B34/06 E21B21/10 F16K15/06 

FIELD: mining.

SUBSTANCE: return valve contains a hollow cylindrical body and disposed and located there the following components: the fixed saddle, forming by its inner surface with the inner surface of the valve body the flow path channel for fluid from the drilling string; as well as contacting with the saddle movable locking unit with disc-shaped head, providing that contact, with rigidly connected with it and tightening the locking unit to the saddle by spring-loaded rod in the form of the central rod with shank, with locking unit clamp relatively to the saddle and covering the rod shank by the locking plug with the slot for the locking unit clamp. At that the valve is additionally equipped with a hollow conical plug, covering the locking plug and supporting by its large base the disc-shaped head of the locking device, and its body is made as one piece and locking unit clamp is made as the press-fitted pin into the rod relatively to the saddle. At that the locking plug slot for the locking unit clamp is made as profiled-blind, providing due to its form the opportunity not only of free axial movement of the pin rod in it at vertical movement of the locking unit, but also the possibility of its locking in this groove at the forced rotation of the locking unit around the axis, and also the subsequent exit from it under the action of the fluid flow from the drilling string, falling to the head of the locking unit. The rod spring is installed on its shank in the locking plug, and the locking unit itself, generally, with its disc-shaped head, its spring-loaded rod with a pin, the conical and the locking plugs formed in the stable relatively to the axis of the one-piece unit valve, installed in the valve channel separately from the body under its saddle, and the fixed valve saddle is designed as a single metal sleeve fixed in the housing.

EFFECT: increase of valve reliability and manufacturability.

2 dwg