Emergency Sealant Enables On Stream Butterfly Valve Repair
The challenge
Mitigating the wear and tear of pipeline systems is an enduring concern for plant managers, maintenance engineers, and asset integrity teams across the oil and gas sector. Valves are especially vulnerable to abrasion from hydrocarbon fluids, particularly in high‑pressure pipeline applications and critical isolation points. The flow medium comes into contact with internal components such as the seat, which plays a vital role in sealing a valve. Over time, deterioration is inevitable and valve repair and refurbishment work needs to be undertaken as part of planned and unplanned maintenance strategies.
Butterfly valves are particularly challenging. Since they don’t have a cavity, it’s traditionally been difficult to reseal them effectively on‑stream without removal from the line. Butterfly valves have a high installed base in most process plants, refineries, and petrochemical facilities due to their compact design and cost‑effectiveness. However, their ongoing valve maintenance, seat leakage issues, and repair requirements can result in costly unplanned downtime, production losses, and safety risks.
The solution
Severn has developed a progressive technology to overcome this challenge: SPIRES® (Sealant Pressure Injection Reserve Endurance System). The solution incorporates an emergency sealant system as a fundamental design feature of butterfly valves, delivering a robust on‑line valve sealing system. Should the primary seal fail, a secondary sealant is injected into a runner behind the disc to compensate for any seat leakage when the valve is closed, enabling live leak sealing without shutdown.
Since the sealant system is wholly independent of the main seals, damage to the main seals does not affect its operation. The objective is to achieve a bubble‑tight shut‑off in accordance with industry valve performance standards, even if the seat is badly damaged, avoiding the need for unplanned downtime or hot work interventions.
SPIRES® offers the capability that plants are accustomed to with ball valves with sealant injection ports. However, it also brings the benefits of cost efficiency, face‑to‑face options, and low weight associated with butterfly valve design, making it an ideal solution for oil and gas pipeline operators, process engineers, and shutdown reduction programmes.
The outcome
Saudi Aramco has conducted a stringent performance assessment of the SPIRES® technology as part of its valve qualification and reliability testing programme. A test specimen’s soft seat was damaged with cuts of 26 different depths in four locations. Depths varied from 0.004 inches to 0.036 inches to simulate severe butterfly valve seat damage and advanced leakage conditions.
The butterfly valve was connected to a test rig and a nitrogen flow was established, reaching ANSI Class 150 operating pressure at 19.5 bar. This resulted in a leak rate of around 1,200 l/min, representative of critical valve leakage in operational pipelines.
The sealant was then injected through one of the ports to close gaps at a pressure of approximately 2,000 psi at the pump. This resulted in the closure of the nearest group of cuts. The further group was closed when injection was switched to the other port. At this point, total valve sealing was established and pressure started to build up to the required level.
Next, the pressure was dropped to zero and the tubular run was checked, with no abnormality detected. The results of this validation testing show that SPIRES® offers an effective solution to repair damaged butterfly valves in situ, supporting asset life extension, operational continuity, and plant safety improvement initiatives.
Proven benefits for operators
- SPIRES® enables badly damaged butterfly valves to be repaired in situ, delivering measurable benefits including:
- Reduced unplanned shutdowns
- Lower maintenance and replacement costs
- Improved valve reliability
- Enhanced operational safety
- Increased plant availability and uptime
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