ROV TOOLING 360-degree neutral buoyancy safeguards subsea valve operations

Bofors Underwater Systems/Sutec has collaborated with Oceaneering to develop an electrical torque tool designed to open underwater valves which is operable from Sutec's Sea Owl and Sea Hawk ROVs or the Sprint vehicle.

Bofors Underwater Systems/Sutec has collaborated with Oceaneering to develop an electrical torque tool designed to open underwater valves which is operable from Sutec's Sea Owl and Sea Hawk ROVs or the Sprint vehicle.

A key aspect of the system is that the ROV can operate with neutral buoyancy and at any angle through 360 degrees. This is important since the tool would otherwise loosen or, in the worst case, break off the valve lever if it were attached to an ROV that was not neutrally buoyant. The weight of the tool (78kg in air) is compensated by flotation materials so that the ROV remains weightless in water. The tool design is compatible with all subsea valve interfaces.

With 360 degree manoeuverability, the Sutec ROVs can reach valves that would normally have to be handled by a large work ROV system, and at 950Nm, the torque rating of the tool is impressive. The tool has a rotational accuracy of 1/100oth of a turn and a torque adjustment accuracy of to within 1%.

The torque tool has a depth rating of 500 metres and a built-in emergency release system in case of ROV power failure. The system took a year to develop and has been used successfully in the North Sea since sea trials were held in April 1996.

For more information contact Bert Ohlsson, Bofors Underwater Systems/Sutec: telephone +46 1315 8060 or fax +46 1315 1320 or Charles Hanson, Oceaneering Norway: telephone +47 51 810800 or fax +47 51 81 0990.

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