Rotork Fluid Systems has supplied its specialised hydraulic actuator package for a second sub-sea safety isolation valve (SSIV) installation on the same offshore gas gathering project off the coast of Egypt.
The single acting, spring-return rack and pinion actuator, model number GSR-2-490-110F/CX, will operate a 16in ANSI Class 900 ball valve installed on the 11km export pipeline from the Seth Platform. This pipeline connects to the Tuna Platform export pipeline end manifold for onward transport to the shore via the TNW2 Platform.
The new actuator will operate an SSIV installed at a depth of 84m near to the Seth Platform, which, together with a check valve installed upstream of the ball valve, will prevent any gas backflow in the event of a pipeline or riser rupture in the proximity of the platform.
A dedicated electro-hydraulic umbilical from the platform will control the actuator, whilst an integral valve manifold system on the actuator itself will enable local diver operation.
In addition, an actuator and gearbox declutch mechanism completes the provision of total valve control under all operating conditions, in combination with an ROV (Remotely Operated underwater Vehicle) interface. The installation is very similar to the Rotork actuated SSIV package that was previously supplied for the 24in export pipeline from the Tuna Platform in the same gas field.