Sophisticated Anti-Surge valve technology from Severn leverages advanced actuation capabilities to deliver precision control, maximising LNG plant efficiency, safety, and productivity.
Controlling centrifugal compressor surge is a fundamental aspect of efficient LNG production, and Anti-Surge Control Valves play a vital role.
Surge events can damage critical rotating equipment, harm plant performance, and result in costly unplanned downtime. Yet a conservative approach to surge risk management compromises plant efficiency and productivity by constraining the compressor’s operating envelope. Identifying an acceptable trade-off between these two extremes is increasingly difficult as trends in LNG production evolve.
The escalating challenge of LNG surge control
Challenges surrounding compressor surge control have become significantly more difficult in the quest for optimised efficiency. With global demand for LNG growing, the capacity of existing and future ‘mega trains’ is increasing. This requires larger valves sizes, which makes it harder to achieve fast, accurate control in anti-surge applications.
Surge events can occur within milliseconds and without warning, meaning Anti-Surge Control Valves must operate with exceptional speed and precision. However, fundamental principles of physics and engineering make it harder to achieve critical performance parameters as valve size increases. The mass of larger valves introduces greater mechanical inertia, so more force is required to control the travel of the plug (the main moving part). Handling larger volumes of gas also introduces significant dynamic inertia and pressure delays, further impeding valve response times.
On LNG plants where Anti-Surge Control Valve travel exceeds 18”, operators traditionally had to tolerate conservative surge control measures, compromising overall plant efficiency. Until now…
Raise the surge control line, boost efficiency
Severn’s latest innovation addresses issues associated with larger Anti-Surge Control Valves head on. Our engineers have applied their technical expertise to the development of a robust, highly engineered solution.
Benefits include fast operability, high controllability, excellent reliability, and extremely accurate valve control. This means the valves respond very quickly (in less than two seconds, including any deadband), without compromising controllability when surge is imminent. As the below diagram shows, these superior performance characteristics enable centrifugal compressors to operate closer to the surge control line, optimising performance and efficiency.
Severn recently completed testing on a proof-of-concept Anti-Surge Control Valve with a nominal bore of 30” and a linear stroke (the distance the actuator travels) of 24”. The valve specimen’s pressure rating was ANSI 150, and it was designed with a flow coefficient (Cv) exceeding 7700, in line with the process conditions of a typical Anti-Surge application.
Testing showed that the valve meets all required parameters of the world’s most stringent Anti-Surge specifications. A significant highlight was its ability to perform the full 24” stroke in less than two seconds while simultaneously achieving incredibly precise positional control. The exceptional performance enables accurate and reliable control close to the compressor surge control line, striking an effective balance between safety and efficiency without concession or compromise.
There is a great variation in centrifugal compressor process conditions, in terms of feed gas properties and operating parameters such as flow rate, pressure, and temperature. It follows that Anti-Surge Control Valves must be individually specified and designed to optimise compressor performance and, in turn, maximise LNG plant performance and efficiency. Future articles in this series will explain how technical aspects of our Anti-Surge Control Valve technology, such as control optimisation and trim design, are customised to meet specific application needs and requirements.
Meanwhile, if you’re looking for expert technical input on centrifugal compressor surge control or other severe or critical service LNG valve applications, contact us at sales@severnvalve.com
Severn has a strong track record in the design and manufacture of valves that overcome the most challenging technical issues. LNG projects we’ve supplied in the past include Ichthys and Gorgon.
With their direct influence on safe, economical plant performance, compressors are a vital component of the LNG liquefaction train. Protecting them from the ‘surge phenomenon’ helps avoid costly damage and unplanned downtime.
Centrifugal compressors are critical to LNG production, raising the pressure of feed gas so it meets the thermodynamic requirements of liquefaction. Highly engineered and complex in nature, they are also expensive – typically costing millions of dollars.
Under normal process conditions, the impeller within a centrifugal compressor rotates at high speed accelerating the flow of the feed gas. It’s important that the inlet flow rate is sufficient to maintain this forward movement and keep the gas flowing along the liquefaction train. However, changing process demands across the wider system can cause fluctuations, bringing the need for extremely fast and accurate mitigation measures.
What is ‘compressor surge’ and why must it be controlled?
The surge phenomenon occurs when inlet flow stalls because it is insufficient to overcome the high pressure at the compressor’s discharge point. This results in a reversal of flow which can trigger a surge cycle: compressed gas rushes backwards through the impeller, reversing the flow direction of the gas and thus reducing discharge pressure and potentially stalling the compressor. As discharge pressure lowers, forward flow resumes, only to be reversed again.
Compressor stall and surge events happen within a 20 – to 50-millisecond window without warning and, if left unchecked, a surge cycle will continue indefinitely. The extent and immediacy of any consequences depends on the frequency and power of the surge force, the vibrations it generates, and the temperature of the surging gas. Associated risks range from short-term performance issues to catastrophic failure of the compressor and lengthy, costly unplanned downtime.
LNG project owners and engineering, procurement, and contractors (EPCs) need to consider the following factors when making decisions about surge control:
Surge damages the compressor, compromising performance
A surge can damage compressor seals, with their replacement costing tens of thousands of dollars. Surges can also cause significant mechanical damage to bearings, the impellers or the shaft, and other critical components. As well as hindering the plant’s operational efficiency, a damaged compressor is more prone to leakage, posing a serious risk to safety and the environment.
Consequences of compressor surge can lead to LNG plant shutdown
Stable operation is vital to the safety and efficiency of an LNG liquefaction train. Flow reversal can lead to major process-related problems requiring emergency shutdown. The repair or replacement of damaged compressor components can also necessitate downtime. Unplanned LNG plant shutdown has a major impact on production. It can lead to significant financial losses, possibly up to tens of millions of dollars, further highlighting the critical importance of a fast, accurate solution.
Minimising the gap between ‘surge’ and ‘surge control’ maximises plant performance
Reducing the likelihood of compressor surge is critical. Yet, while a surge event can have serious consequences, an overly conservative approach to surge risk management constrains the compressor’s operating envelope, limiting overall plant efficiency. Effectively balancing risk requires a range of measures, from fast, accurate, dynamic control systems to predictive analytics and regular maintenance.
Severn has the solution to the enduring surge control challenge
Severn has engineered a sophisticated Anti-Surge Control Valve solution with advanced actuation capabilities to overcome this enduring challenge of LNG production.
Severn brings extensive experience in the design and manufacture of LNG valves for both the cryogenic and liquefaction phases of production. Previously, we’ve supplied severe and critical service valves for LNG liquefaction projects such as Gorgon and Icthys.
Contact us to find out how we can support your LNG development goals.
With a few weeks until IEW 25, Severn, a renowned leader in fluid control solutions, is thrilled to introduce the dynamic team of valve experts who will be representing the company at IEW 25 in Delhi from the 11-14 February.
As the world gears up for one of the most significant gatherings in the energy sector, Severn’s selection of experts promises to elevate the discourse on cutting-edge valve technology and innovation.
Join us as we unveil the names and expertise behind Severn’s delegation, offering a glimpse into the exceptional insights and knowledge they will be bringing to IEW 25.
With over 19 Years of experience in the Oil and Gas Industry (specialising in Upstream & FPSO), Control Valves and Chokes with broad and specialised technical knowledge. Malathy brings a whole range of skills to the IEW team such as professional approach, decision-making, problem-solving, interpersonal skills, etc.
Alongside technical expertise, Malathy also has fantastic commercial acumen, winning large project orders, handling complex projects that involve new design and developments, special materials, quality, validation testing, etc., and possesses good exposure to International Standards (API, ASME, ISA, ASTM, and other relevant standards).
Malathy is currently working to expand the supply base of Severn products globally, especially in Southeast Asia, the Middle East Market, South America, Africa, etc., and is a fantastic addition to the Severn IEW 2025 team.
With 29 years of experience in the valve industry, Kannan’s knowledge expertise, and global awareness from working in multiple functions such as sales, application engineering, and project management have made him a respected figure in the Control Valve market with clients, earning him a reputation as a reliable and dynamic leader.
Kannan’s ability to anticipate market trends, build lasting relationships, and inspire his team is a testament to his unparalleled expertise and unwavering dedication to Severn, thus making him a valuable member of the IEW 2025 team.
Rajendran – Industry Manager – Application Engineering – LNG & Industrial Gas
Rajendran is a key account manager, focussing on enhancing the customer experience with key customers.
With 20 years of experience in the field of Control Valve Application Engineering and Project management, he is in charge of business growth from key account customers of the Oil & Gas and Industrial Gas segments. He established credibility in handling small to large size Project & OEM orders from other industry segments such as Refining, Fertilizers, and Water.
He is into leveraging Severn’s strength with core customers by establishing frame agreements and driving projects for process improvements, value stream mapping, and lead time reduction.
He is further assigned to diversify the business in new geographical segments by posturing collaboration and value proposition. His expertise in Oxygen service and Cryogenic Valve applications supports customers in their emerging process control and automation requirements.
A seasoned Control Valve professional with a decade of expertise in the Oil and Gas Industry (specialising in Oil & Gas – Onshore, Refinery & Petrochemicals).
Chandru excels in delivering optimised Control Valve solutions to our customers (EPC’s and OEM’s) and is recognised by our customers for 24×7 consultation on any unique challenges / services related to control valves in their projects.
Alongside technical expertise, Chandru is adept at identifying market trends, commercial aspects and customer pain points, translating these insights into customised Control Valve solutions that enhance customer satisfaction and expand Severn Products’ Global supply base.
RK – Director – India Sales
RK joined Severn in 2017 as General Manager of Sales & Marketing to develop Domestic & Indian Subcontinent business.
With over 35 years total sales experience in process industries including Projects & MRO business, now as Sales Director of India region, RK identifies and captures new business opportunities with his strategic skillset and has delivered outstanding results, catapulting Severn to new heights in the Indian market.
With a proven track record of achievements in the Indian market, RK has become instrumental in driving revenue growth and expanding market share whilst forging lasting partnerships with clients and collaborators.
Gaurav – DGM – India Sales
Gaurav comes with a rich experience of two decades in the field of Sales & Business Development of Mission Critical Flow Control Products which play an important role in improving Process Efficiency, Uptime, Asset Management of an End User Process Plant together with Product Life-Cycle Management, New Market Developments thereby contributing to Organizations growth.
With Severn he is entrusted with developing the Project Business for our Severe Service Control Valves from Indian customers for both Domestic and International Projects through support of Field Sales Team with Severn’s values of Customer First, Integrity, Accountability & Excellence at the core of all the activities conducted.
Its our pleasure to invite you for a engaging discussion on business association, collaboration, emerging trends and flow control industry as a whole for a win-win relationship.
A seasoned leader in Valve Solutions bringing over 18+ years of experience in delivering top-tier solutions to industrial clients worldwide. My Journey in this field has been shaped by a strong foundation of technical expertise, customer-focused strategies, and innovative problem-solving. Comprehensive knowledge of valve industry processes systems, spares, and replacement strategies to optimize performance and reliability. Has a proven track record of diagnosing complex operational challenges and delivering efficient, cost-effective solutions. Deep understanding of client needs, ensuring tailored solutions that align with operational goals.
Leading a team committed to excellence in providing world-class on valves aftersales solutions. Our focus is on enhancing system performance, minimizing downtime, and ensuring our clients’ operations run seamlessly.
Sanjeev – Senior Manager – MRO – India Sales
With 17+ yrs of experience in Flow control industry, Sanjeev provides the techno-commercial expertise, clients relationship management, enhancing overall customer experience with after sales support, valves solutions for various customers within Oil & Gas Industry.
Sanjeev is overseeing MRO opportunities in India region, he is a trusted & well-versed with Severn’s core Control Valves products range & solution driven approach supporting end-customers to find solutions, enhance their efficiency, reliability and productivity, especially in severe services & challenging applications in process industries.
Do you want to find out more about Severn’s attendance at IEW 25?
Severn Glocon’s Control valves are engineered to meet the stringent requirements of ISO 15848-1, specifically achieving Class A certification for fugitive emissions for pressure ratings up to #2500 which is best-in-class. ISO 15848-1 sets rigorous standards, classifying valve performance based on their ability to contain emissions.
Conventionally, Class A packings are required when any Mutagenic Carcinogenic chemicals, methane, toxic media, hazardous gases and sour gases are suspected to be evident. It is reported that the Oil & Gas industry is responsible for 15% of global energy-related Green House Gas (GHG) emissions. Due to this reported figure, it becomes vital to address these emissions through valves.
Why is ISO 15848-1 Critical for Fugitive Emissions?
This ISO standard evaluates valve sealing performance against fugitive emissions, which can be unintended leaks of volatile or hazardous gases. The certification involves multiple tests, including temperature and pressure cycling, as well as leak rate assessments. Notably, Severn’s valves are capable of meeting the highest (Class A) for stem and body seals, ensuring leak rates remain minimal which is crucial for handling hydrogen sulphide-rich sour gas applications in the Oil & Gas sector.
Technical Aspects:
Severn Glocon’s compliance with Class A specifications under ISO 15848-1 includes advanced seal design that undergoes stringent helium detection testing. In these tests, valves are exposed to high pressures, and leak rates are assessed using sensitive equipment like a helium mass spectrometer leak detector (MSLD). The rigorous testing provides assurance of valve integrity, even under extreme thermal cycling, mechanical cycling, and varying pressures.
Meeting the Challenges of Sour Service:
Valves in sour service handle gasses containing H₂S, which is both highly toxic and corrosive. Severn’s use of specialised materials and advanced sealing techniques ensures resilience against corrosion and leak prevention. This positioning enables Severn to offer reliable solutions that comply with the environmental regulations, prevent harmful emissions, and support the sustainability objectives of Oil & Gas operators.
Ready for High-Sour Service Applications
Severn Glocon’s valves, equipped with FE Gland Packing, are capable of withstanding the highly corrosive environments typical in sour gas applications. The materials and unique sealing mechanisms ensure reliability and minimise corrosion between the stem and packing material, reducing the frequency of maintenance while ensuring top-tier emissions control.
Contact the Severn team of experts for best-in-class engineering assistance with your valve operational issues:
Severn Glocon UK Valves Ltd is a world leader in the design and manufacture of severe service Control, Choke and Butterfly valves. For clients in Scotland and operating in the North Sea, Severn Aberdeen based in Portlethen, serves as the regional hub for both OEM valves sales and service support whilst also offering comprehensive third-party valve support.
OEM Control, Choke and Butterfly valve Support
As an integral part of Severn Glocon UK Valves, Severn Aberdeen specialises in sales and service support for Severn’s Control, Choke and Butterfly valves. These valves are specifically designed for severe service conditions, ensuring reliability, precision performance and longevity. The engineering expertise that Severn Glocon UK and the Aberdeen facility has allows the team to tackle the most challenging environments, providing clients with performance and reliability they can trust.
Third-Party Support
Beyond OEM support capabilities, Severn Aberdeen extends its capabilities to third-party manufacturers. Whether you’re dealing with Control, Isolation, Pressure safety (PSV’s) or Pressure Relief Valves (PRVs), the Severn Aberdeen team provides expert sales and service. This ensures our clients has a one-stop facility for their complete valve management, from procurement to servicing, across a wide range of valve types.
Engineering Expertise at Your Fingertips
Severn Aberdeen’s unique advantage comes from being part of an Original Equipment Manufacturer (OEM). This allows the team to offer unparalleled engineering support to operators and EPCs. Clients can witness their valves and actuators being stripped, tested, and reported onsite while consulting directing with Severn’s expert engineering team for immediate problem diagnosis and resolution. This hands-on approach ensures transparency and rapid decision-making, keeping projects on track for clients.
Complete Testing, Overhaul, and Offshore Support
Severn Aberdeen offers a full suite of testing and overhaul services at the Aberdeen facility. In addition, there is a team of certified valve technicians and offshore containers for offshore TARs (Turnarounds) and onshore shutdowns. This ensures smooth, seamless operations with minimal downtime, reducing the impact on your product schedules and maximising efficiency.
Why Choose Severn Aberdeen?
Expertise across extensive valve product types.
Unmatched engineering support.
Comprehensive service capabilities.
Local support for Scotland and North Sea region.
Partner with Aberdeen for all your valve needs – OEM or third-party- backed by world class engineering and service support.
Contact the Aberdeen team today to discuss how we can optimise your operations and help you achieve your core imperatives of safe operations and minimum downtime: sales@severnvalve.com
Severn Aberdeen: Your Go-To Partner for OEM and Third-party Valve Solutions.
Severn Glocon, a global leader in industrial valve engineering and manufacturing, is proud to announce the opening of its new Engineering Centre of Excellence. Located in Halifax, the Engineering Centre of Excellence is set to drive innovation, enhance engineering expertise, and reinforce Severn Glocon’s ongoing commitment to delivering best-in-class-solutions to customers across the energy, oil & gas and process industries.
The new Engineering Centre of Excellence will serve as a hub for advanced engineering projects, fostering collaboration across disciplines and enabling the development of cutting-edge valve technologies that meet the most stringent of industry standards and customer demands. By leveraging the latest in design, simulation, and testing capabilities, Severn Glocon is positioned to continue offering high-performance, bespoke solutions that deliver reliability, performance and efficiency in the most challenging operational environments.
Jonny Walker, UK Engineering Director, Severn Glocon, commented:
The launch of the Engineering Centre of Excellence marks a pivotal moment for Severn Glocon. This facility will be the engine that drives our next phase of innovation, combining industry-leading expertise with the latest technological advancements. Our team of highly skilled engineers will have access to the tools and resources they need to push the boundaries of what’s possible in valve design, development, and performance. It’s a significant investment in our people and processes, reinforcing our commitment to engineering excellence.
This new facility will support Severn Glocon’s commitment in developing solutions that drive operational efficiency and assist in reducing environmental impact as part of the effort to meet the evolving needs of modern industry.
John Long, Divisional President, Severn Glocon, added:
At Severn, we pride ourselves on being engineering-led and solutions-focused. The establishment of the Engineering Centre of Excellence is a testament to our dedication to maintaining that ethos. This investment enables us to deliver more innovative, robust and customised solutions for our clients. Our customers operate in demanding sectors where reliability and precision are paramount, and this facility strengthens our ability to meet – and exceed – their expectations.
The Engineering Centre of Excellence will also play a critical role in Severn Glocon’s training and development programs, offering a unique environment for upskilling future engineers and deepening expertise across the organisation. It will support the company’s talent pipeline, ensuring Severn Glocon remains a leader in valve engineering and manufacturing for years to come.
As the global demand for energy continues to evolve, Severn Glocon’s new Engineering Centre of Excellence is set to drive the next generation of valve technology and provide best-in-class engineering solutions to customers around the world.
Discover how engineering excellence and heritage has driven Severn’s OCT TOV Butterfly Valve to deliver unmatched reliability in Seawater environments.
Severn’s research & development team has designed a Butterfly Valve that solves the problem of galvanic corrosion and meets strict fire test standards. Utilising the over 60 years of engineering excellence, the team of technical experts achieved this by using Severn’s patented Oblique Cone Technology (OCT). The OCT-SW takes this patented technology to the next level by eliminating the need for graphite in the seal and maintaining firesafe capability.
What is galvanic corrosion and its costly effects?
The impact of galvanic corrosion on critical assets due to seawater process conditions is an enduring problem for offshore oilfields. At best, it increases the workload and repairs associated with planned shutdowns. At worst it can result in rapid or unexpected damage, leading to unplanned or emergency shutdowns. Either way, it is a costly problem which harms efficiency, putting additional pressure on plant operating costs. However, Severn have utilised their engineering heritage, research and development & repair intelligence knowledge to develop a valve that deals with the issue of galvanic corrosion head on.
Why does galvanic corrosion occur? The cause of galvanic corrosion (also referred to as ‘dissimilar metal’ or ‘bimetallic’ corrosion) is an electrochemical reaction between two different conductive materials in close proximity. It results in one – the least noble of the two – being preferentially corroded. To combat this risk, the general rule is ‘do not mix metals’. However, when it comes to the design and development of assets for harsh offshore environments, things are rarely that straightforward.
Modern critical safety systems used on offshore sites are often highly sophisticated
to cope with the extreme natural conditions and industrial challenges with which they must contend. They come with extreme technical demands but must manage physical ones too; systems that need to feed water to combat fires must be durable enough to cope with the corrosive effects of the sea. Seawater service valves play an integral role in the process and their ability to either supply or isolate sections of the water line is a vital safety feature. Therefore, eliminating galvanic corrosion while maintaining firesafe credentials has been an enduring challenge for the industry.
In recent years, the use of graphite sealing technology has surged. Graphite’s extreme range of properties and characteristics makes it an ideal material in many ways. It is soft, flexible, and easy to cut, but it has high heat resistance and is almost inert. However, it is also the only non-metal that can conduct electricity. Furthermore, its nobility exceeds that of noble metals including stainless steel, bronze, and titanium. Yet it is often paired with these materials in valve manufacture, in the form of seals, packings and gaskets. From a galvanic corrosion perspective, graphite has become not only the solution to problems but can often be the cause.
Traditionally, Triple Offset Butterfly Valves have used graphite materials in their construction, which can cause galvanic corrosion in seawater applications. This is a problem because it can significantly reduce the effectiveness of the valve’s sealing components, compromising safety and leading to potential costly unplanned downtime.
By working closely with end users and operators, Severn has recognized this issue, and with its significant engineering heritage and technical expertise, has designed a long-term solution. The Severn team of engineering experts designed a valve that either replaces the graphite components completely or stops them from contacting the line media. This significantly reduces the risk of galvanic corrosion in day-to-day operations and ensures the highest level of safety. Ensuring you achieve safe operations and minimal downtime.
The Oblique Cone Technology (OCT) Seawater (SW) Triple Offset (TOV) Butterfly valve is a revolutionary type of valve designed primarily for use in saline applications, such as offshore oil and gas operations. These valves play a pivotal part in safety systems, as they play a crucial role in firewater systems. Due to Severn’s engineering heritage and technical expertise in the oil and gas operations sector, this valve has been designed with over 60 years of engineering excellence ensuring it helps the end user achieve their core remit of safe operations and minimum downtime.
Severn has developed a hybrid polymer metallic seal that moves away from the use of graphite laminates. By utilising a primary metallic seal with a secondary polymer seal, not only have Seven removed the graphite from the seal but have additionally increased the valves isolation sealing capabilities and maintained the firesafe performance crucial for such critical applications. This coupled with isolating any graphite gaskets and packings from encountering the line media means that at no point during the normal operation of the valve do the graphite and seawater mix, eliminating the risk of galvanic corrosion and the costly effects it can have on production.
In addition to addressing the corrosion problem, Severn’s Butterfly Valves also meet important fire test standards such as API 6FA, API 607, and ISO 10497 accreditations. As such the OCT Valve is certified fire-safe and can be relied upon in critical emergencies for the end user and operators, ensuring safe operations and minimal downtime.
The team also took steps to ensure the valve design could not generate a spark and risk starting a fire itself. They followed the ISO/IEC 80079-36:2018 ATEX standard and ensured that no static charge could build within the valve. This additional element of care renders the new OCT-SW valve design suitable for a wide range of applications, beyond seawater service further emphasising the versatility of the valve design.
The OCT-SW can be manufactured from corrosion-resistant materials such as Aluminium Bronze, Super Duplex, and Titanium, with the added knowledge that anti-blowout protection comes as standard. Available in standard and non-standard face to face dimensions and various body styles such as lugged and double flanged, the valve can be easily retrofitted into existing pipeline spaces and is an ideal upgrade when operators are experiencing issues with galvanic corrosion.
Severn understands the ongoing challenges operators face with reducing and eliminating fugitive emissions and have created a technical solution with the design of its Oblique Cone Technology Triple Offset Butterfly Valve.
Operators are under increasing pressure to reduce fugitive emissions for both onshore and offshore assets in order to achieve their core imperatives of safe operations and minimum downtime. Severn realises the role they play in today’s climate conscious world to help reduce and eliminate fugitive emissions from valves. Utilising the engineering heritage and extensive knowledge in severe service applications, Severn ensures it can offer the most suitable product for the end user.
Through Severn’s ‘Repair Intelligence’ and close operating relationships with end user operators, Severn has been able to understand the difficulties facing operations in the specification, purchasing and servicing of Control, Choke and Butterfly valves that are critical to reducing fugitive emissions across industrial facilities. Severn prides itself in offering technical solutions that perform no matter how severe or critical the application is. Ensuring that the end user gains the best valve performance and reduced maintenance costs over the lifecycle of the valve.
It has long been understood that approximately 60% of fugitive emissions come from valves. Even more so 80% of those emissions are related to the stem/shaft seal. Naturally, the focus is on this area with the relative fugitive emissions standards such as API 622 and ISO 15848. What is often misunderstood is the requirement for the standards to be applicable across varying temperature and pressure differentials. For this reason, Severn has 43 different certificates for sealing systems in valves based on their application requirements, up to 10,000 Psi and 425ºC. By utilising a range of materials from filled graphite through to custom PTEE-based compounds, Severn has, coupled with novel packing designs, been able to achieve tighter leakage rates that had previously been achieved with standard packing sets.
It is vital for the end user to understand the leakage class requirements when fugitive emissions are concerned to prevent over or underspecifying the solution. We often see “fugitive emissions” specified without clarification of the requirements. The various requirements from TUV through API and ISO specifications require different testing methodologies and even different testing mediums. This means that the testing standards are not directly comparable to each other. Severn often see the specification of “Low-e” or “Low emission” packing without reference to the specification. In some instances, these packing sets can have allowable leakage of up to 500ppm, many times that of systems tested to the ISO 15848-1 standard and potentially resulting in detrimental reduced on-site performance and / or higher maintenance costs.
Severn has focused and will continue to focus its testing efforts on ISO 15848 standards as it is understood that these offer the widest range of qualification options whilst not utilising harmful greenhouse gases that can be emitted using some API methodology. The fact that sealing systems are tested on the valves they are designed for and not a standard test fixture ensures maximum customer confidence in our products performance and reliability.
Severn have focused on passing some of the most stringent testing with class A leakage classes and up to 40,000 operations available for some applications. Ensuring that performance is at the heart of our product range, and you achieve your core remit of safe operations and minimum downtime.
To further the commitment to reducing fugitive emissions and reduce the burden on end users to meet tightening specifications, Severns OCT Triple Offset Butterfly Valve offers the fugitive emissions packing sets as standard fitment on all standard valves in the range. Ensuring that the end user experiences maximum valve performance in all applications.
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.
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.
The Laminate seal is the “traditional” Triple Offset Valve seal and consists of multiple metal and graphite layers providing isolation sealing.
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).
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.
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.
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.
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.
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.
