John Crane has launched the Type 8628VL, a next generation mechanical seal engineered to solve the oil and gas industry’s toughest challenges: maintaining sealing integrity in multiphase ethane and ethylene pipelines. Designed to perform under volatile pressure and temperature conditions, the Type 8628VL leverages spiral groove non-contacting technology to deliver exceptional reliability, operational efficiency, and environmental compliance.

Solving the Multiphase Challenge in Pipeline Infrastructure

Ethane pipelines present unique challenges due to frequent fluid phases shift from liquid to vapour to supercritical, which can compromise conventional seal performance. The Type 8628VL addresses this by employing dual non-contacting seal faces in a tandem configuration, a design validated by peer-reviewed Lubricants (MDPI) research. The research confirmed that spiral groove non-contacting seal faces deliver superior hydrodynamic lift, phase-change resilience, and zero-wear operation in volatile fluid applications, ultimately allowing ethane pipelines to eliminate friction and wear while using the process fluid in these different states to provide lubrication.

Initial Field Installations on the U.S. Gulf Coast

A leading ethane transmission company operating along the U.S. Gulf Coast faced a major operational challenge: Managing phase change during pumping with pressure variations. Ethane, which exists as a liquid at around 18^oC (65 ^oF) and 40 bar (580 psi), transitions to vapour at approximately 32^oC (89 ^oF). This phase change created sealing and reliability issues, impacting uptime and seal life.

The operator installed four Type 8628VL seals on ethane pump equipment experiencing inconsistent performance at ~1100 psi. Three months into continuous operation and intermittent shutdowns, the results were clear:

• Non-contacting performance across all phases – liquid, vapour and supercritical
• Extremely low leakage
• Zero failures

“The performance is exactly what we hoped for — consistent, reliable, and robust. We now have full confidence in uptime,” said a senior reliability engineer from the customer site.

In addition, the deployment delivered measurable improvements in service turnaround, local service centre support and reduced refurbishment times.  It also lowered the costs associated with complex refurbishment, while the seal’s multiphase capability eliminated a key cause of premature seal failure.

Key Benefits:

• Enhanced Reliability: Operates nearly twice as long as conventional wet seals with liquid barrier fluid, with a mean time between repair (MTBR) of up to 48 months and beyond.
• Efficiency and Sustainability: Requires only 2-3 GPM of flush fluid – a fraction of the 10-30 GPM fluid required when contacting seal faces are applied. This reduces the size and capacity and resulting cost of flush fluid systems used with contacting seal technology.
• Lower Operating Costs: Requires minimal maintenance, with operations targeting MTBR of 48 months and beyond.
• Dramatically simplified sealing support systems: The dual unpressurised arrangement eliminates the need for complex API Plan 54 or 53B systems. This eliminates liquid barrier fluids and the cooling water associated with such systems.

Competitive Differentiation in a Changing Market

“Unlike hybrid or contacting seals, the Type 8628VL delivers pure non-contacting operation, even during rapid phase transitions,” said Mike Eason, Chief Technology Officer at John Crane.  It’s a significant step forward for the sector,”

Eason added: “We will continue to expand our portfolio with products that meet customer reliability and energy transition goals. The Type 8628VL is a testament to our commitment to innovate for greater efficiency zero greenhouse gas (GHG) emissions”.