CIRCULATION SUB Russian patent published in 2021 - IPC E21B21/10 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas industry, in particular to switching flow of drilling fluid in a drill string. A device contains a case with a spool sleeve with a seat and a guide ring in the input part located in it, and a spring pressing the spool sleeve to the guide ring. In the case, there are two circulation ports with flow holes, a sleeve with side holes and a spool sleeve located in it, the sleeve has a collar in the output part. To the case, a threaded case of the device for catching balls is fastened, in which a filter pipe is located with slits in its wall and an input sleeve and an output flange connected to it. The guide ring is made with thread on the outer surface, the thrust collar is formed by a flange fixed on the end of the sleeve, the flange has protrusions that enter grooves of a shank of the spool sleeve. The filter pipe is connected by welding to the input sleeve and the output flange in one removable sub assembly suspended on the inner conical surface of the case of the device for catching balls in its upper part. In the lower part, the assembly is centered - it is freely located inside the output sleeve. The guide ring is located above the seat, which is installed in a detachable way in a socket of the spool sleeve, and which rests on a socket ledge, a pair of radial holes is made in the spool sleeve.

EFFECT: installation and dismantling works are simplified, the reliability of the sub operation is increased.

2 cl, 4 dwg