In case of blowout and well-sealing is needed, high pressure oil coming from control system enters the bottom closing chamber from bottom inlet to push piston moving upward. The movement of piston forces rubber core to move upward along the sphere surface, then supporting ribs get closer to push the internal rubber moving towards the wellhead center to fulfill the function of sealing drill equipment or the wellhead. When unlocking the seal is needed, hydraulic oil pushes the piston moving downward and the rubber core will reset to its original position under its elastic force.