CIRCULATION VALVE Russian patent published in 2002 - IPC

FIELD: well testing with fluid direct and reverse circulation in pipes. SUBSTANCE: installed in side body is piston with spring in upper part and collet in lower part. With collet freed from conical boss, spring moves piston to its lower position. Radial channels are opened and pipe cavity is communicated with annular space to provide for fluid circulation in direct and reverse directions with the help of forcing units. It provides control over level of formation fluid produced in inflow process and reliable operation of valve. EFFECT: reliable operation of valve and simplified its servicing. 1 dwg