Why major gas operators are switching to Amarinth sealless API 685 magnetic drive technology

The power of containment

The advantage of an API 685 magnetic drive pump lies in its contactless transmission. Instead of a physical steel shaft coming through the pump casing to connect with the motor (which creates a gap that must be sealed), the pump is hermetically sealed in a solid containment shell. Power is transmitted from the motor to the impeller via high-strength magnets. These are attracted together through the solid metal wall of the pump, spinning the internal components without any physical contact.

API 685 magnetic drive pumps offer a number of advantages over API 610 pumps with traditional mechanical seals:

• Leakage Risk: 100% containment; no wear of seals; no physical gaps.
• Maintenance: No seals to wear out; minimal intervention; no top-up system; lower lifetime maintenance costs; less spares and maintenance required.
• Footprint & Complexity: Streamlined, self-contained unit with small footprint; no ancillary support systems and piping.
• Environmental: Zero-emission design; supports Environmental, Social, and Governance (ESG) goals.

Pushing the limits

For years magnetic drives were regarded as a solution for light duties only. Historically, the pump industry suggested that magnetic drive couplings would "slip" or become unreliable once a pump required more than 50kW to 75kW of power.

Amarinth has recently broken through these boundaries however by engineering high-torque magnetic couplings capable of seamlessly handling operational loads up to 110kW. This allows operators to bring sealless, hermetic security to high-flow, high-pressure duties where previously there was no choice but to rely on high-maintenance mechanical seals.

Amarinth has achieved this milestone through key engineering innovations in magnet design, metallurgy, and thermal mitigation:

• Advanced Rare Earth Metallurgy: Utilises the strongest commercially available permanent magnets (such as Samarium or Neodymium) to keep the coupling drive radius and length to an absolute minimum. These materials provide approximately a 40% higher torque capacity compared to standard alternatives.
• Optimised Magnetic Mass & Sync Configuration: Combines superior magnet grades with increased magnet mass to maximise total transmittable torque. The unit features a minimised air gap between the rotors to ensure maximum torque density, maintaining a synchronous coupling that delivers a secure magnetic lock with zero slip.
• High-Temperature Structural Integrity: Pushing past the 100kW threshold requires exceptional temperature stability and resistance to demagnetisation. Amarinth utilises next-generation bonding adhesives and epoxies to secure the magnets within the inner and outer rings, ensuring long-term mechanical reliability under high thermal loads.
• Neutralising Eddy Current Losses: A stronger magnetic field naturally increases parasitic Eddy Current (EC) losses, generating localised heat inside the metallic containment shell. Amarinth counters this by utilising containment can materials with a significantly higher electrical resistance. This directly suppresses the eddy currents, allowing the drive to operate coolly, safely, and efficiently at 110kW without compromising power throughput.

The VS4 revolution

Most magnetic drives are horizontal or vertical in-line and designed for clean floor space. However, many hazardous refinery fluids reside in underground sumps or drain drums. Amarinth has developed a VS4 vertical sump version of the API 685 pump, allowing toxic wastewater and oily sumps up to 10 meters deep to be managed with zero-leakage security.

To achieve this, Amarinth overcame two vertical pump magnetic drive limitations:

• Containment Can Venting: Vertical configurations naturally trap vapours at the top of the containment shell, risking dry running and heat buildup. Amarinth engineered a self-venting system that clears vapor pockets to ensure the containment zone remains flooded.
• Resilient Bearing Materials: Amarinth utilised advanced bearing materials to resist wear and tolerate transient dry-run conditions during startup.

The "dirty" fluid myth

A common industry myth is that magnetic drives are too delicate for fluids containing sand, grit, or scale. Amarinth challenged this by redesigning the flow paths. By optimising how fluid moves inside the pump along with the addition of external flush ports, Amarinth pumps can now work in environments like oily water separators, handling particulate levels that would cause reliability issues in a standard magnetic drive.

A safer, simpler future

By eliminating the mechanical seal, Amarinth is helping the gas industry transition from "managing leaks" to "eliminating them." The result is a plant that is not only safer for the people working in it but significantly more profitable due to reduced downtime and a lower operating and maintenance overhead. In the modern gas plant, the API 685 magnetic drive is no longer just an alternative, it is the new standard for responsible, future-proofed operations.

Beyond gas

While the gas industry has led the way in adopting API 685 technology, a significant shift is now occurring in the oil sector. Major oil operators are increasingly recognising that the "triple threat" of safety, environment, and finance is just as prevalent in crude oil extraction and refining as it is in gas processing.

This interest from the oil industry is driven by three primary factors:

• Refining volatile hydrocarbons: Modern refineries handle a variety of light, highly volatile crude fractions. Much like the "flash factor" in gas, these fluids pose significant fire risks if they escape through traditional mechanical seals. The hermetic containment of the Amarinth magnetic drive provides a reliable security layer for these high-risk zones.
• Offshore and remote asset management: On offshore platforms, space is at a premium and maintenance logistics are incredibly costly. By eliminating the need for bulky Seal Support Systems and the frequent manual intervention they require, oil operators are turning to API 685 pumps to move toward unmanned or minimum facility platforms.
• Aggressive environmental mandates: With global pressure to reduce Volatile Organic Compound (VOC) emissions, oil companies are under pressure. Transitioning to sealless technology allows these operators to report true "zero-emission" performance for their pumping assets, directly supporting corporate ESG (Environmental, Social, and Governance) targets.

As oil fields become more complex and environmental regulations tighten, the transition from API 610 mechanically sealed pumps to Amarinth’s API 685 magnetic drive sealless solutions is accelerating. What began as a revolution in gas processing is now redefining reliability across the entire energy value chain.

Offshore Rig, Norwegian North Sea

Amarinth delivered a critical engineering upgrade for an offshore oil platform in the Edvard Grieg oil field, situated approximately 150km off the Norwegian south-west coast in a water depth of 110 metres.

The operator faced severe spatial constraints on the platform, where deck space was at a premium and logistics for maintenance were exceptionally costly. The existing traditional API 610 centrifugal pump relied on a bulky, high-maintenance mechanical seal support system, complete with an array of ancillary tanks and complex piping that demanded frequent manual intervention and regular fluid top-ups.

To overcome these constraints, Amarinth replaced the legacy unit with a compact, sealless API 685 horizontal magnetic drive pump. To ensure long-term structural and chemical integrity against corrosive marine elements, the pump was manufactured in super-duplex stainless steel conforming to strict specifications. By transitioning to a magnetic drive, the system utilised contactless power transmission from the motor to the impeller via high-strength permanent magnets separated by a solid metal containment shell, achieving a 100% hermetically sealed environment. This eliminated the need for external seal support structures, greatly minimising the equipment's overall physical footprint.

The sealless upgrade successfully provided the exact required process duty within a streamlined profile, completely removing the safety and environmental risks of fugitive emissions while significantly lowering ongoing lifetime maintenance costs and removing the necessity for frequent human intervention in hazardous offshore zones.

Ruwais NGL Trains, UAE

Amarinth was selected for an urgent modernisation project at the Ruwais Natural Gas Liquids (NGL) processing trains in the United Arab Emirates. The project demanded a fast-track solution to upgrade the facility's tanks handling highly toxic, aggressive, and volatile NGL fractions, substances classified as "untouchables" within the industry. These light hydrocarbons present an extreme "flash factor," meaning any microscopic escape through a traditional mechanical seal would instantly expand into highly flammable vapour clouds, creating an immediate explosion risk.

Faced with a strict 28-week delivery timeline, Amarinth engineered and supplied an integrated package consisting of two API 685 horizontal OH2 magnetic drive pumps and three API 685 VS4 vertical sump magnetic drive pumps. By deploying sealless technology, Amarinth established an uncompromising zero-leakage barrier. The hermetically sealed containment shell entirely isolated the volatile fluids, removing the failure pathways associated with traditional wear-prone mechanical seals.

To guarantee operational security under intense process conditions, the pumps were fitted with bespoke containment zone instrumentation, including temperature alarms and advanced vibration monitoring systems. This successful fast-track deployment enabled secure total fluid containment, safeguarding on-site personnel from toxic exposures, and eliminating traditional mechanical seals that required operators to manually check and top up barrier fluids every 28 days.

Major LNG Expansion Project

Amarinth achieved a major technical breakthrough by engineering a bespoke suite of API 685 VS4 vertical magnetic drive sump pumps for a high-profile Liquefied Natural Gas (LNG) processing expansion project in the Middle East. The project was bounded by extreme spatial constraints and an absolute mandate for zero-leakage security when managing volatile hydrocarbons and chemically aggressive solvents trapped in underground drain drums. Traditional vertical pumps with mechanical seals were unfeasible due to severe space restrictions and the large footprint required for external seal support systems.
The in-ground hydrocarbon drain tanks measured just 2 meters wide, requiring Amarinth to develop slender, 5.5-meter-long vertical pumps. Working closely with the tank fabricator using advanced computer modelling, Amarinth optimised bearing spacing along the long shaft to suppress destructive resonance and ensure mechanical stability during demanding startup conditions.

To overcome the natural tendency of vertical configurations to trap vapours at the top of the containment shell, which risks dry running and heat buildup, Amarinth engineered an innovative self-venting system that ensures the containment zone remains flooded. Additionally, a specialised "gulley sucker" arrangement was integrated at the base to effectively remove sediment and debris from the very bottom of the tank. Finally, because site access was tightly restricted, a custom-engineered baseplate aligned all critical gauges and instrumentation within a single, optimised viewing angle for safe, streamlined visual monitoring.