ROV Activated J-Tube Seals are installed on to the riser prior to over-boarding and engaged into the J-Tube via the riser pull-in operation.
Normally the J-Tube Seal is connected to the pull-in head via a quick release system that will disconnect under load as the seal mechanically engages with the bellmouth. Alternatively, the system is clamped directly to the riser to allow the J-tube seal to enter the bellmouth prior to activation. The clamp can either allow the riser to be pulled-through at a given force, or released completely to allow the rise to free float through the centre of the seal. The release mechanism for the clamp is hydraulic & operated subsea by the ROV.
Following successful pull-in of the J-Tube seal, activation is conducted hydraulically. Supergrip UK provide a rental Subsea HPU, which is pre-programmed to operate at the required pressures during the factory acceptance testing of the product.
The Subsea HPU is lowered to the seabed separately, or alternatively connected directly to the ROV. A hotstab unit will connect the Subsea HPU to the J-Tube seal, a hotstab connection for the ROV is also included to provide power to the subsea HPU. This system means that no hydraulic downlines are required from the vessel to operate the seal.
The HPU includes a secondary low-pressure hydraulic circuit to allow pressure testing of the J-Tube seal following activation, confirming the integrity of the product.
ROV Activated J-Tube Seals can be proved in a continuous or split construction to assist with topside installation on to the riser.
• Riser sizes: 4”ns – 24”ns
• Bellmouth sizes: 6”ns – 48”ns
• Sealing pressure > 20 bar.g
• Design life: >50 years
• Mechanical or ROV riser release system during installation
• Supergrip field proven mechanical locking nuts allow hydraulic removal
• Supergrip mechanical locking nuts incorporate hydraulic release for seal assembly removal.
• Seal verification pressure testing capability