02 Nov Visual Position Indicator Case Study
63 Existing VPI’s are installed at various locations around the rig to provide mechanical visual indication of each Ballast Valve position. At each VPI location there is a small emergency operation block with needle valve which is fully closed to allow connection of a hand pump via a QDC for manual emergency operation if required.
As the emergency operation block is upstream of the VPI, should the VPI fail there is the possibility that the manual hand pump operation may not fully function the valve actuator.
This resulted in the rig requesting a solution that allowed for a “Bypass” of the VPI if necessary.
As the VPI was mounted on a Cetop 3 subplate we developed a method to remove the existing Cetop 3 Subplate and manufacture a new bespoke manifold with three integrated Isolation Valves whilst retaining the Cetop 3 interface for the VPI. We also included the provision of 2 QDC’s that resulted in the existing emergency operation block also being removed from the circuit. The new manifold now allows the complete bypass of the VPI in the event of failure along with the ability to still carry out Emergency Operation of the Ballast Valve when required.
Utilising a bespoke manifold arrangement has greatly reduced the installation cost over inline valves and extensive pipework reworking while providing the required functionality and emergency back up requirements.