Offshore compression project benefits from Severn’s valve innovation

Extreme technical demands associated with a critical safety system on an offshore gas compression platform are being addressed with a new valve technology from Severn Glocon Group.

The valve engineering specialist is supplying 17 highperformance triple offset Butterfly Valves to control seawater in the fire safety system of the platform, located off Trinidad and Tobago.

The bi-directional isolation valves need to achieve repeatable zero leakage and meet stringent fire safety testing standards. In addition, the end user specification requires avoidance of wetted graphite inside the valves.

Triple offset Butterfly Valves are typically constructed with graphite packings, gaskets and laminated metal/graphite seals.

In normal operation this noble material provides good service, but increased risk of galvanic corrosion in seawater applications is an ongoing concern for offshore operators.

Avoiding contact between graphite components and the line media, without compromising fire safety credentials or overall valve performance, presented a significant technical challenge.

To address this, the engineering team devised an innovative adaptation of Severn’s patented Oblique Cone Technology (OCT®). Introducing a hybrid valve seal eradicated the need for graphite, whilst retaining all the inherent advantages of a triple offset valve.

The double-flanged valve bodies are manufactured in aluminium bronze for general seawater resistance, and they also incorporate internal and external anti-blowout protection. This advanced safety feature ensures the shaft cannot blow out, even if all external bolting is accidentally removed.

Simon Walker, Severn’s Technical Authority – Butterfly Valves, led the development process. He says applying a logical, methodical approach helped resolve the application problems:

“Standard, catalogue valve products couldn’t satisfy the specification for these valves, so we were enlisted to solve the issue for our client. However, there is also an enduring industry need to overcome the galvanic corrosion problem. We set out to create a solution that could benefit the entire market, not just a single bespoke application. It was a challenging task, but as we specialise in arduous valve applications, we were wellequipped to handle it. Testing has shown that the technology we developed is both reliable and repeatable, and we’re shipping to the end user one month ahead of schedule.”

Tel: 0845 223 2040

Published in Valve User Magazine Issue 51

Winter 2019 // Issue 51
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