Discover how engineering excellence, and offshore flow control innovation have driven Severn’s OCT TOV Butterfly Valve to deliver unmatched reliability in seawater service valve applications and harsh offshore environments.
Severn’s research & development team has designed a Butterfly Valve for Seawater Applications that solves the problem of galvanic corrosion in offshore systems and meets strict firesafe valve standards. Utilising over 65 years of engineering excellence in industrial valve design, the team of technical valve specialists achieved this by using Severn’s patented Oblique Cone Technology (OCT). The OCT‑SW Butterfly Valve takes this proven control and isolation valve technology to the next level by eliminating the need for graphite in the seal while maintaining full firesafe performance required for critical offshore safety systems.
What is galvanic corrosion and its costly effects?
The impact of galvanic corrosion in seawater valve systems on critical offshore assets due to marine process conditions is an enduring problem for offshore oil & gas installations, FPSOs, and sealine infrastructure. At best, it increases maintenance workload and repair activity during planned shutdowns. At worst, it can result in rapid or unexpected valve failure, leading to unplanned production downtime or emergency shutdowns.
Either way, galvanic corrosion presents a significant lifecycle cost risk that negatively impacts plant efficiency, operational reliability, and total cost of ownership. However, Severn has utilised its engineering heritage, in‑house R&D capability, and valve repair intelligence to develop a seawater butterfly valve solution that tackles galvanic corrosion head‑on.
Why does galvanic corrosion occur?
The cause of galvanic corrosion (also referred to as dissimilar metal corrosion or bimetallic corrosion) is an electrochemical reaction between two different conductive materials in close proximity within an electrolyte, such as seawater processing systems. One material – typically the least noble – is preferentially corroded.
In offshore valve design, the classic rule of “do not mix metals” is difficult to achieve due to extreme environmental conditions, fire safety requirements, and stringent materials specifications.
Modern offshore safety systems, such as firewater systems, must withstand continuous exposure to corrosive seawater, while delivering reliable isolation and control valve performance during normal operation and emergency conditions. Seawater service valves therefore play a critical safety role, making the elimination of galvanic corrosion while maintaining firesafe valve certification a long‑standing industry challenge.
The graphite challenge in seawater valve applications
In recent years, graphite sealing technology has become widespread in industrial valve manufacture due to its excellent thermal resistance, chemical stability, and flexibility. However, graphite is also the only non‑metallic electrical conductor and is more noble than many metals commonly used in offshore valve construction, including stainless steel, bronze, and titanium.
As a result, when graphite is exposed to seawater in contact with these metals, it can accelerate galvanic corrosion, particularly within seawater butterfly valves, control valves, and firewater isolation valves.
Traditionally, Severn’s Triple Offset Butterfly Valves utilised graphite in parts of their construction, which in seawater service applications could contribute to galvanic corrosion. Over time, this may compromise sealing integrity, valve reliability, and plant safety, potentially leading to costly unplanned outages.
Engineering a long‑term seawater valve solution
By working closely with offshore operators, EPC contractors, and end users, Severn identified this challenge and applied its extensive engineering heritage and technical valve design expertise to develop a long‑term solution.
The Severn engineering team designed a valve that either eliminates graphite entirely or isolates it completely from the line media, significantly reducing the risk of galvanic corrosion during normal operation. This ensures the highest levels of operational safety, asset protection, and system reliability, supporting the industry’s requirement for safe operations and minimal downtime.
OCT‑SW Triple Offset Butterfly Valve for Seawater & Firewater Systems
Severn’s OCT‑SW Triple Offset Butterfly Valve is a high‑performance seawater valve solution developed specifically for offshore sealine applications, firewater systems, and marine utility services.
These valves play a pivotal role in offshore safety systems, particularly where rapid isolation, reliable shut‑off, and firesafe operation are mandatory. Leveraging over 65 years of oil & gas valve engineering experience, the OCT‑SW valve has been designed to help operators meet their core objectives of safety, reliability, and reduced downtime.
Hybrid metallic‑polymer sealing technology
Severn has developed a hybrid polymer‑metallic sealing arrangement that removes the need for graphite laminates. By combining a primary metallic seal with a secondary polymer seal, Severn has:
- Eliminated graphite exposure to seawater
Increased isolation valve sealing performance
Maintained full firesafe valve certification
Furthermore, by ensuring that any remaining graphite gaskets and packings are fully isolated from the process media, the design prevents graphite and seawater from ever coming into contact. This eliminates galvanic corrosion risk, protecting production uptime, asset integrity, and operating efficiency.
Certified firesafe and ATEX‑compliant valve design
In addition to mitigating corrosion, Severn’s Butterfly Valves for Seawater Applications meet key firesafe testing standards, including:
- API 6FA
- API 607
- ISO 10497
This confirms the OCT‑SW valve as a certified fire‑safe valve, suitable for critical emergency scenarios.
The design also complies with ISO/IEC 80079‑36:2018 (ATEX) requirements, ensuring that static charge build‑up is eliminated and preventing any risk of spark generation. This makes the valve suitable for a broader range of hazardous area applications, extending beyond seawater service and reinforcing its versatility.
Materials, retrofitting & offshore suitability
The Severn OCT‑SW Butterfly Valve can be manufactured in a range of corrosion‑resistant materials, including:
- Aluminium Bronze
- Super Duplex Stainless Steel
- Titanium
Anti‑blowout protection is provided as standard. Available in standard and non‑standard face‑to‑face dimensions, with lugged and double‑flanged body styles, the valve can be easily retrofitted into existing offshore pipeline systems. This makes it an ideal upgrade solution for operators experiencing galvanic corrosion issues in seawater valve systems.
Severn’s engineering heritage and technical expertise have led to the OCT TOV Butterfly Valve being future-proof for changes in the process conditions to provide increased versatility for the end user seeking reliable high‑performance triple offset butterfly valves, industrial isolation valves, and severe‑service valve solutions.
From the outset, Severn made flexibility a key driving force in the design of the Oblique Cone Technology (OCT) Triple Offset (TOV) Butterfly Valve. Due to Severns extensive diverse engineering heritage and excellence, our expert team of engineers understand that processes and application product demands change over time, whether it is the process conditions or the overall requirements of the valve for the end user. Due to this understanding, the Oblique Cone Technology Triple Offset Butterfly Valve has been designed to incorporate multiple seal options, all fully interchangeable with each other, providing maximum application diversity and usability to ensure safe operations and minimum downtime making it ideal for oil & gas isolation, refinery valve applications, petrochemical process valves, and critical shutdown and control operations.
The Laminate seal is the “traditional” Triple Offset Valve seal and consists of multiple metal and graphite layers providing isolation sealing for high‑temperature, high‑pressure, and severe‑service applications.
The OCT HS seal is a hybrid polymer metallic seal, this seal benefits from a primary metal seal and secondary polymer seal, this provides a reliable and repeatable bubble tight seal time after time. This can also be paired with PTFE packings when graphite being in contact with the line media is a concern. The polymer seal is fully compliant with EN ISO 80079-36 (ATEX) making it an excellent choice for ATEX‑rated butterfly valves, hydrocarbon service valves, and zero‑leakage industrial valves.
The OCT SW Valve takes the hybrid sealing to the next level with its versatile high performance. Severn utilises the OCT-HS seal and has designed a valve that ensure there is no graphite in contact with the line media to remove the risk of costly galvanic effects such as internal corrosion leading to valve failure. Whilst doing so the OCT-SW also maintains firesafe certification making it suitable for Firesafe Triple Offset Valves, API 607 certified valves, and critical isolation applications in hazardous environments.
Should the sealing requirement not become as critical, and process conditions become more arduous, the Laminate and Hybrid seals can be changed for the OCT-SS solid seal. As the name suggests it is a solid metallic seal, that can be made from hard-wearing alloys to add longevity to the sealing life of the valve in arduous conditions and can offer a control valve seat leakage ideal for erosion‑resistant valve applications, abrasive service, and high‑cycle industrial operations.
Based on Severns comprehensive history of severe service control, our team of engineering experts work closely with operators and end uses to identify the correct seal and material selection to provide the maximum reliability and productivity further ensuring minimum downtime supporting industries such as LNG, chemical processing, power generation, and midstream pipeline operations.
All the OCT seals are interchangeable and can be upgraded without the need for main valve components being replaced, further emphasising the OCT TOV Butterfly Valves versatility. The fully in field serviceable valve can be upgraded on-site without the need for specialist tools or knowledge, this further ensures that costly unplanned downtime and site waste is kept to a minimum, along with potential loss in production for the end user. All the seal options can be changed on site within a small space of time to ensure site maintenance costs are reduced by upgrading the existing valve rather than discarding and replacing with a commodity product each time making it a cost-efficient solution for industrial valve maintenance, asset lifecycle extension, and retrofit valve upgrades.
Each OCT valve is specially designed to be versatile and ensure it has multiple purposes for multiple conditions whilst still delivering maximum performance. With the introduction of the interchangeable seal, these can be easily swapped out to match the end users’ requirements, should they change ensuring adaptability for future process changes, sustainability improvements, and long-term operational efficiency.
Incorporating over 65 years of engineering excellence and technical expertise in valve engineering and application, Severn Valves offers an industry leading and patented valve engineering technology solution(s) for Butterfly Valve requirements and applications with the Oblique Cone Technology (OCT) Triple Offset (TOV) Butterfly Valve. By utilising Severn’s ‘Repair Intelligence’ knowledge which involves providing real market feedback from extensive in-depth analysis from failed valves. Severn Valves have designed each facet of the OCT TOV Butterfly Valve to provide the most accurate, reliable, and robust service capability and performance possible to help the end user achieve their core remit of safe operations and minimum downtime.
Severn’s Triple Offset Butterfly Valve Cutting Edge Design Features Leads to Comprehensive Application Coverage.
Severn’s OCT Butterfly Valve design uses circular sealing geometry, unlike traditional triple offset butterfly valve designs that use an ellipse. The benefit of circular geometry is that it provides a uniform sealing load around the circumference of the sealing diameter, providing a reliable and repeatable shut-off. By using circles rather than ellipses, it allows Severn valves to use proven circular sealing knowledge and incorporate this into the TOV Butterfly Valve.
In addition, to this we can also add specialised flow control trims that are traditionally found on Severn’s double offset butterfly valves. These control trims include Anti Cavitation / Low noise, half baffle & full baffles. We can also add special features such as steam jacket and purge ports should they be required, onto our Triple Offset Butterfly Valve design.
Process conditions can change with time. Severn valves have ensured the interchangeability of the seal, should the sealing requirement not become as critical, or process conditions become more arduous. The HS seal can be changed to a laminated seal, or if conditions dictate, a solid seal. This can be done without the need for main valve components being replaced. The complete in-field serviceable valve can be upgraded on site without the need for specialist tools or knowledge ensuring possible down time and loss in production is kept to a minimum.
The interchangeability and versatility of the seal allows for Severn’s Triple Offset Valve to be used for both isolation and control applications and processes. The diversity of the OCT TOV Butterfly Valve and its functional usability for an extensive range of both isolation and control applications leads to the potential savings in stock holdings for end users who can use stock this one valve instead of stocking two. This in turn allows for potential cost savings for the end user on stock holding by reducing the need to stock multiple valves due to the extensive coverage that the OCT TOV Butterfly Valve offers.
Severn valve has designed all their Triple Offset Butterfly Valves with safety as paramount and therefore engineered the product with anti-blowout at both ends of the valve. This negates any chance of the shaft blowing out. The reduced shaft diameter at the drive end ensures the shaft cannot blow out through the packing follower and anti-blowout ring on the threaded shaft end ensures positive engagement without the need for additional fasteners.
The OCT range also comes with hard facing on the disc as standard with options to upgrade the standard hard facing to weld overlays such as stellite 6, ensuring and reliable seal and extended service life.
A quarter turn design ensures ease of actuation for both control and isolation purposes. Whether this be via an actuator or gearbox, the quarter turn design allows for simple operation.
As standard, Severn’s OCT TOV Butterfly Valve includes fugitive emission packing to ISO 15848 with options to change to meet customer specific requirements such as Shell 77/312 available.
The OCT valve range has been firesafe tested & certified in accordance with the strict fire test specifications set out in the standards ISO 10497, API 607 & API 6FA. Withstanding extreme temperatures of up to 1000°C whilst still sealing. Further underpinning the performance capabilities and validating the valve performance, ensuring this valve can be suitable for an extended range of applications and process requirements, leading to safe operations and reduction unplanned downtime for the end user.
Severn offer the OCT TOV Butterfly Valve in all cast materials. From basic carbon steels to specialist alloys such as Monel, Titanium & Hastelloy. Severn can provide the correct material selection for your application. Additional surface coatings such as stellite, armoloy, chrome or weld overlays are available upon application and request.
Severn are breaking tradition with the innovative OCT Butterfly Valve and lifecycle enhancement service.
In the fast-paced industrial landscape, the emphasis on sustainability and cost-effectiveness has never been greater. Severn’s Oblique Cone Technology (OCT) Triple Offset (TOV) Butterfly Valve is at the forefront of a new era in valve technology, where the focus shifts from immediate replacements to intelligent lifecycle enhancement and repair strategies which makes repair not replace valves. This paradigm shift not only promotes sustainable valve maintenance but also ensures safe operations, reduced downtime, helping you achieve your core remits.
Lifecycle Enhancement: Prolonging Valve Longevity
The traditional approach to valve maintenance often involves a “replace-first” mentality. However, Severn’s OCT TOV Butterfly Valve challenges this norm by offering a comprehensive lifecycle enhancement program by repair not replace valves. Through cutting-edge innovative engineering and materials, Severn’s OCT TOV Butterfly Valve is designed to withstand harsh operating conditions, ensuring a longer lifespan with its patented Oblique Cone Technology Triple Offset capabilities for both isolation and control applications.
By prioritizing lifecycle enhancement, industries can optimise their assets, reduce overall operational costs, and minimise the environmental footprint associated with the manufacturing and disposal of new valves.
Repair Intelligence: Smart Solutions for Complex Issues by Severn’s Repair not Replace Valve
Severn’s OCT TOV Butterfly Valve affirms the concept of Severn’s repair intelligence as the valves are designed with modular components, facilitating easy disassembly and reassembly during repairs. This not only reduces maintenance costs but also minimises the need for complete valve replacements, contributing to a more sustainable and cost-effective approach to industrial operations.
Sustainable Valve Maintenance: A Green Approach
Severn’s commitment to sustainability goes beyond the valve’s design. The OCT TOV Butterfly Valve promotes a circular economy by encouraging refurbishment and reconditioning of components. With our expert team of service engineers based globally, we can retrofit, service and repair any of our Butterfly valves on site if performance has dropped or specification or operating conditions have changed, this ensures production downtime is kept to a minimum.
Furthermore, sustainable valve maintenance aligns with global initiatives to reduce carbon emissions. By extending the life of industrial equipment, companies can decrease their carbon footprint associated with manufacturing and disposal, contributing to a greener and more environmentally responsible future.
Safe Operations and Reduced Downtime: The Ultimate Value Proposition
The OCT TOV Butterfly Valve prioritise safety through rigorous testing and compliance with industry standards such as API 598. By implementing repair intelligence and lifecycle enhancement strategies, Severn can ensure the continued reliability and safety of their valves and valve systems.
Moreover, the ability to address issues proactively minimise unexpected costly downtime. This not only enhances operational efficiency but also safeguards against potential safety hazards, ensuring a secure working environment for personnel.
Environmental Impact: A Positive Footprint for Future Generations
By choosing repair over replacement and embracing Severn’s lifecycle enhancement, industries using Severn’s OCT TOV Butterfly Valve actively contribute to reducing the environmental impact of their operations. Through sustainable valve maintenance practices, companies can align with global environmental goals, demonstrating corporate responsibility and leadership in their respective sectors.
Severn’s OCT TOV Butterfly Valve signifies a paradigm shift in the industrial valve landscape. By championing lifecycle enhancement, repair intelligence, and sustainable valve maintenance, this product offers not just cutting-edge technology but a comprehensive solution for industries seeking a balance between operational efficiency, environmental responsibility, and cost-effectiveness. In a world where every decision impacts the planet, choosing to repair, not replace, is a step towards a more sustainable and resilient future.
United Kingdom, 23rd June 2021: Severn Glocon UK Valves Limited and ValvTechnologies have reached an agreement to form a strategic partnership that will see collaboration between two of the world’s leading engineering and manufacturing companies specializing in innovative, high-end, severe-service valves.
Subject to regulatory approval in the U.S., Severn and ValvTechnologies strategic partnership will combine the brands’ distinctive and complementary capabilities to extend the global reach, product offerings and customer service of both companies. Backed by Bluewater, the international energy private equity firm, the collaboration will see many customer and sales synergies that will offer significant added value to the marketplace.
Headquartered in the UK and with premises worldwide, notably manufacturing facilities in India, Severn specializes in control, choke and small-bore subsea valves for the energy industry. Headquartered in Houston, Texas, ValvTechnologies also has premises worldwide, and is the global leader in the design and manufacture of metal-seated, zero-leakage, severe-service valve solutions for the harshest applications.
Kevin Hunt, President at ValvTechnologies, comments: “Both Severn and ValvTechnologies have a long history of mutual respect. Now, working more closely together, we can provide a broader range of engineered solutions to the severe-service marketplace. That’s great news for our customers.”
Steve Waugh, Chairman of Severn, adds: “Each company has been founded on technical prowess and commitment to innovation. Through this new combined force for the global valve market, we believe we will provide an enviable range of solutions and services in our industries.”
About Severn
Founded in 1961 and headquartered in Gloucester, United Kingdom, Severn Glocon UK Valves Limited is a leading manufacturer of control valves and related products worldwide. The company offers a wide range of severe service control, choke and general service valves, associated actuators and peripheral equipment, bespoke built special application control & choke valves, providing valve management as well as general engineering support services to oil and gas, LNG, power and other process plant users.
About ValvTechnologies
Founded in 1987 and headquartered in Houston, Texas, ValvTechnologies is the leading manufacturer of zero-leakage, high-performance isolation valve solutions providing an unsurpassed level of severe service isolation services and reliability to customers in the fossil power, nuclear generation, upstream oil and gas, downstream and chemical processing, mining and minerals, pulp and paper and other specialized industries.
About Bluewater Bluewater is a specialist international private equity firm focused on the middle-market energy sector. Its experienced investment and operating professionals drive value creation as they manage $2.5billion of investment across a portfolio of 22 companies. Today it has a prime focus on projects or technologies that contribute to the energy transition agenda, and works to a diversified investment strategy based on the principles of sustainability and close working partnerships with best-in-class management teams. It has a strong focus on ESG, and is a signatory to the UN Principles for Responsible Investment.
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Severn makes ice-road deadline.
An ice-road waits for no one, so Brighouse engineers had their work cut out ensuring six butterfly valves were ready to reach a north Russian LNG plant before the spring melt.
The order comprised four 20” ASME 300 and two 16” ASME 900 double flanged short pattern triple offset butterfly valves.
To ensure Severn makes the ice-road deadline, the Brighouse team designed, manufactured, assembled and tested the valves in-house, comfortably shipping them by the mid-March deadline.
Manufactured in CF8M with electric actuators, these control valves surpassed the customer’s Class IV leakage requirement, achieving the more challenging ‘Class VI or better’ standard.
Severn manufactures and supports high quality valves for the energy industries. Its control, choke and small bore subsea valves are pre-eminent in the global market, underpinning the reliability and high performance of business-critical client infrastructure.
Severn’s global reach, technical prowess, and collaborative approach – all founded upon a heritage of British engineering excellence – help to assure production continuity for clients and reduce the prospect of costly downtime.
Its understanding of the life-cycle of assets positions Severn to offer end-to-end engineering solutions, enabling clients to meet their core imperatives: safe operations and minimum downtime.
Severn celebrating 20 years with Shell.
Back in 2000 Severn Unival secured a valve management contract for Shell’s North Sea platforms. Each time the contract has come up for renewal we have retained the business. The contract was recently renewed again, marking 20 years of working together. The strength and duration of this customer relationship are testament to the high level of service and technical expertise we bring and is a major factor in Severn celebrating 20 years with Shell.
Severn manufactures and supports high quality valves for the energy industries. Its control, choke and small bore subsea valves are pre-eminent in the global market, underpinning the reliability and high performance of business-critical client infrastructure.
Severn’s global reach, technical prowess, and collaborative approach – all founded upon a heritage of British engineering excellence – help to assure production continuity for clients and reduce the prospect of costly downtime.
Its understanding of the life-cycle of assets positions Severn to offer end-to-end engineering solutions, enabling clients to meet their core imperatives: safe operations and minimum downtime.
Remote inspection technology gains momentum.
Adoption of Severn Oculi, our connected system for the remote inspection of valves, is going from strength to strength. As well as assessing valve condition in the field, the digital system can be used to facilitate remote witness testing.
Severn Glocon Abu Dhabi recently conducted a full pressure, seat leakage and functional test on a 2- 9/16 API 10,000 globe control valve for ADNOC, with the process witnessed virtually by the client team. Various work scopes have been witness-tested in this way in recent weeks to demonstrate the technology to our clients.
The SVS team has also been holding internal video conferences to introduce the technology and its benefits to the wider Group. If you would like to participate in a future demonstration, please contact support@svsi.ae.
With the global pandemic response still restricting movements and international travel, remote inspection technology gains momentum as Severn Oculi is proving to be a valuable tool. It’s set to deliver a good return on investment, improving cost efficiency for Severn and our customers alike.
Severn manufactures and supports high quality valves for the energy industries. Its control, choke and small bore subsea valves are pre-eminent in the global market, underpinning the reliability and high performance of business-critical client infrastructure.
Severn’s global reach, technical prowess, and collaborative approach – all founded upon a heritage of British engineering excellence – help to assure production continuity for clients and reduce the prospect of costly downtime.
Its understanding of the life-cycle of assets positions Severn to offer end-to-end engineering solutions, enabling clients to meet their core imperatives: safe operations and minimum downtime.
BOC praises 24-hour critical valve repair turnaround.
In the middle of February, BOC called us to investigate a recycle valve that was not stroking properly at its Worsley plant. This was a repeat problem which we’d previously resolved by adjusting the positioner. On this occasion when Field Service Technician, Jake Wood inspected the valve it was clear that the positioner needed to be replaced. Contracts Manager, Dave Morrison promptly contacted Project Engineer, Tracy Chapman in Gloucester who quickly advised us on several replacement options. One of these was already in stock in the Brighouse stores. So, Jake was despatched to BOC Worsley again the following day where he successfully installed the replacement part. This is a great example of multiple facilities collaborating to deliver a high level of customer service.
BOC praises 24-hour critical valve repair, as both the maintenance supervisor and the branch manager of BOC stated:
“I would just like to thank you for your quick response in getting our N2O filling system back up and running. This is a critical gas which we supply to the NHS and with your help and quick response we have managed to keep the supply chain going.” Mark Derbyshire, Maintenance Supervisor
“[You’ve] been a big help this week. Given the criticality of N2O, it’s prevented us having any immediate shortages to the NHS.” Dan Smith, Branch Manager
In the long-term the entire valve needs to be replaced, and Gloucester’s Tim Webb is on the case.
Severn manufactures and supports high quality valves for the energy industries. Its control, choke and small bore subsea valves are pre-eminent in the global market, underpinning the reliability and high performance of business-critical client infrastructure.
Severn’s global reach, technical prowess, and collaborative approach – all founded upon a heritage of British engineering excellence – help to assure production continuity for clients and reduce the prospect of costly downtime.
Its understanding of the life-cycle of assets positions Severn to offer end-to-end engineering solutions, enabling clients to meet their core imperatives: safe operations and minimum downtime.