CEMENTING VALVE OF CASING STRING Russian patent published in 2009 - IPC E21B33/14 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to technical means employed at boring of well bore with simultaneous casing with casing string, notably for process set of casing strings. There is suggested cementing valve of the casing string; case 4 of the valve is positioned in sub 1 of the casing string made with circular groove 3 on the interior surface, back valve is installed in central channel 5 of the case; seals 25 and 28 are assembled between the case of the valve and inside surface of the sub; also there are installed indicator 17 of fixating the case in the sub and a locking element designed to interact with circular groove 3 of the sub. Cylinder seats 21 are made in part of the valve case located under the back valve; the seats receive locking elements designed to radially rotate; the said locking elements are made as spring loaded holders 22 with a spherical head. The back valve is made as spring loaded cap 6 with plunger 7 in a lower part of which neck 20 is installed; the neck is designed to break.

EFFECT: reduces friction forces and prevents jam of cementing back valve at its trip inside casing string and also ensures receiving clear signal of valve fixation in sub of casing string.

6 dwg