ROTATING UNIVERSAL HYDRAULIC BLOWOUT PREVENTER Russian patent published in 2003 - IPC

FIELD: oil and gas producing industry; applicable for sealing wellhead in well drilling. SUBSTANCE: preventer has body with cavity and central hole, cover with hole, bearings. Sleeve has cavity accommodating sealing member. Sealed piston with stepped external surface is installed in body. Preventer has working, return and relief chambers. Additional hydraulic channels communicate relief and return chambers for directing the pressure from top downward. Diameters of contact of rotating piston with body and sleeve with cover are equal. EFFECT: higher versatility of hydraulic preventer and increased degree of sealing reliability, reduced overall dimensions and weight. 3 cl, 1 dwg