Enhancing Pipeline Operations with John Crane’s Type 8628VL Mechanical Seal 

Equipment reliability and efficiency are paramount in the oil and gas value chains. Ethane and ethylene pipelines, in particular, present unique challenges due to their shifting phases from liquid to vapour. For pipeline operators, maintaining mechanical seal integrity is critical to preventing downtime, reducing repair costs and ensuring safety.  

John Crane offers non-contacting mechanical seals for pumps that leverage spiral groove technology to reduce leakage and direct it to recovery systems, such as vapour collection or flares. Non-contacting technology offers critical advantages over other solutions: increased reliability, improved efficiency with frictionless operation, no wear, no need for oil lubrication systems and suitability for processes involving temperature-sensitive process fluids as no heat is generated. 

Innovative Features Drive Unmatched Sealing Performance

John Crane’s Type 8628VL features an unpressurised tandem arrangement, where the inboard seal is exposed to the seal chamber pressure and is lubricated by the process fluid. The outboard seal captures the small amount of leakage that passes the inboard faces. Both the inboard and outboard seals operate as non-contacting seals, thanks to spiral groove technology. On the inboard side, the grooves move liquid ethane across the seal faces, providing lubrication. As the ethane reaches lower pressure areas, it transitions to vapour, which is used by the outboard seal for lubrication, with only about 1/10th of the vapour required. This non-contacting operation ensures exceptional durability by using different phases of the fluid to lubricate the seal faces. Here's how it stands out: 

• Non-Contacting Seal Faces: John Crane’s Type 8628VL leverages spiral groove technology by creating hydrodynamic lift to maintain non-contacting seal faces, even when process fluid changes from liquid to vapour. This eliminates wear, heat and friction typically seen in traditional face-contacting seals. 
• Phase-Adaptive Performance: Designed for light hydrocarbons, the Type 8628VL operates efficiently in both subcritical and supercritical conditions, ensuring seal performance even as ethane and ethylene fluctuate between phases. The seal uses process fluid and in liquid, supercritical or vapour phase for lubrication, further extending the lifespan of the seal. 
• Extended Mean Time Between Repair (MTBR):  Through its spiral-grooved, non-contacting operation, the Type 8628VL reduces flush volume to just 1/10th of what is required by contacting seals. This results in a far more efficient flush fluid filtration strategy. Additionally, the non-contacting operation eliminates wear and frictional heat, significantly extending MTBR up to 48 months.  

Maximising Operational Efficiency 
The Type 8628VL mechanical seal offers several advantages for pipeline operators: 

• Improved Reliability:  The Type 8628VL is designed for non-contacting operation, using the liquid phase for seal face lubrication. As the liquid crosses the faces, it flashes into vapour, which lubricates the outboard seal faces, further enhancing performance. This is particularly beneficial for operators of ethane and ethylene pipelines, where fluid phase changes are common, helping to minimise the risk of seal face wear and failure. 
• Reduced Maintenance Costs: Unlike traditional contacting seals, which require extensive maintenance and high flush rates, the Type 8628VL’s self-lubricating system reduces maintenance complexity and cost, resulting in a lower total cost of ownership for the operator. Longer MTBR also reduces maintenance costs through reduced repair frequency. 
• Repair Services: John Crane’s global network of about 200 service centres helps reduce lead times for repairs and replacements. For operators, this means less downtime and more confidence in their sealing solutions. 
• Adaptability Across Multiple Applications: The Type 8628VL is suitable for various pipeline applications, including: 
  • Ethane and ethylene pipelines 
  • Point-of-use feedstock 
  • Petrochemical processes 
• Regulatory and Environmental Compliance: The seal design aligns with environmental regulations, especially concerning emissions control. By reducing the need for complex barrier fluid systems like API Plans 54 and Plan 53B, operators can meet regulatory expectations while simplifying their sealing systems. 

Empowering Customers with Enhanced Performance and Reliability 
The Type 8628VL delivers a suite of benefits designed to enhance pipeline operation and maintenance: 

• Minimised Downtime: With extended MTBR and reduced maintenance needs, John Crane’s Type 8628VL increases equipment uptime, allowing for uninterrupted pipeline operation. 
• Cost Savings: Operators avoid the high costs associated with dual wet seals and elaborate flush systems. The Type 8628VL's multiphase lubrication capabilities result in a more durable design, ultimately reducing operational costs. 

Achieving Sustainability and Reliability with the Type 8628VL 
John Crane’s Type 8628VL mechanical seal provides pipeline operators with a reliable, cost-effective sealing solution. Its non-contacting operation improves pipeline efficiency while helping operators meet regulatory and sustainability goals by managing emissions and maintenance needs. In an industry where uptime and reliability are crucial, the Type 8628VL stands out as a leader in sealing technology. 

At John Crane, we’re committed to supporting your sustainability initiatives and enhancing equipment reliability. Contact us to learn how our mechanical sealing solutions, including the Type 8628VL, can help you achieve your operational goals.