For most efficient operation, a self-contained hydraulic closing unit with sufficient accumulator capacity to close the Torus at least three (3) times should be employed. The closing unit should be equipped with a hydraulic pressure regulating valve for controlling the hydraulic closing pressure from the accumulator manifold. The recommended regulated pressure for the Torus is from 800 psi up to the rated working pressure for the BOP. A 4-way, 3-position shear seal valve should be employed on the closing unit to close and open the Torus Annular BOP. The plate above this valve should identify the three positions as “Open”, “Off” (or “Neutral”), and “Close”.
An emergency by-pass valve is recommended to quickly provide maximum manifold pressure to the Torus in the event the wellbore pressure exceeds the regulated hydraulic pressure prior to closure. The closing force to the Torus may be increased by manually adjusting the hydraulic pressure regulator until a seal is obtained or until the maximum BOP working pressure is obtained.