Powerful Magnetic Couplings by FSubsea in Norway Enable Desalination & Underwater Pumping 

Ocean floor dredging enabled by powerful magnetic couplings from FSubsea 

Leveraging its development of a powerful magnetic coupling system that can withstand harsh, underwater conditions, Norwegian company FSubsea is bringing new capabilities in subsea pumping from ocean floors and rugged industrial applications. Coastal desalination plants, underwater dredging and offshore oilfield operations are among the diverse uses in ocean waters. 

Recent contracts include an order for 6 subsea pumps from a large, global player in the deep ocean ROV and dredging industry, who has previously bought multiple subsea pumps from FSubsea. Proven reliability under demanding conditions was a key factor in winning the order. The pumps were to be delivered within three months, which is record time for this type of pump, according to Knut Oppenhagen, FSubsea’s sales manager. 

In August 2023, after rigorous system testing, FSubsea shipped the first commercial delivery of its Flocean subsea desalination plant to a client in the Red Sea. The system takes advantage of the clean and naturally pressurized water at 300-600 meter water depths near shore to produce climate-smart and ocean-friendly freshwater using proven seawater reverse osmosis technology. The system uses 30-50% less energy than modern terrestrial SWRO plants and has no harmful chemical or brine discharge. 

Desalination pods can be aggregated to match the project requirements, scalable to 10 pod systems. 

Flocean can provide water stressed coastal areas with low-cost potable water or simply cold, clean seawater, harvested sustainably from the deeper parts of the ocean. Here, the forces of nature are working in our favour. The system uses the natural pressure of the water column to reduce energy consumption with 30-50% compared to modern terrestrial seawater reverse osmosis facilities. The system is eco-friendly as the deep sea also provides stable, higher purity feed water and virtually eliminates damage to marine life at both the intake and outfall. The subsea reverse osmosis system takes advantage of already qualified equipment, is easy to install and maintain and highly reliable. Capacity is about 7,000-8,000 cubic meters per day per pod. Each pod measures 6m x 6m x 7m (height) and weighs about 50 tons. 

Heavy-duty subsea centrifugal pumps for use on ROV’s, trenchers and other subsea tools or installations are another application for FSubsea’s magnetic coupling technology. Typically, they are used adjacent to a client’s ejector-based systems, or they can be used as subsea jetting or injection pumps. Primary applications are seawater or light slurries. Typical capacities range up to 1000 m3/hr and with generated pressures up to 80 bar. Pumps can be mounted in any direction and equipped with either hydraulic or electric drive. 

Magnetic coupling systems 

The magnetic couplings are a key element of FSubsea systems. They are the world’s most powerful magnetic couplings, says the company, and represent a core technology for it, making critical-application process pumps more reliable and safer. Mechanical seal and barrier-fluid systems are often complex, fragile and can cause more than 60% of failures in pumping systems.  Moreover, leakages can cause risk to health or environment. Traditional seal-less pumps are severely limited and size and power transfer capabilities. 

In addition to enabling topside-less subsea pumps, the system can create more reliable and safer hermetically sealed pumping systems for ammonia, hydrogen, CO2, refinery- and other critical applications. One of the company’s business areas is to help pump original equipment manufacturers make their large pumps seal-less. 

Pressure containment shell tested to 1,034 bar (15,000 psi)
Female half of the magnetic coupling system
Male-part of the magnetic coupling, prior to assembly of protective outer sleeve 

FASTsubsea joint venture

In another project, FSubsea is in a joint venture with Aker Solutions to develop the world’s first topside-less subsea multiphase boosting system. It is designed as a powerful yet simple pump to increase oil recovery for brownfields, tie-backs and marginal or distributed fields. The pump can reduce capital expenditure by up to 50% as it enables subsea boosting at fields where there is no available topside space and gets more out of existing wells. The technology is seal-less, barrier fluid-less and does not need any electric variable speed drive. 

Based in Oslo and established in 2013, FSubsea is an outgrowth of independent pump dealer and service company Fugelsangs AS, now a fifth-generation Norweigian company. FSubsea specializes in designing and delivering robust subsea pumping systems centered around its magnetic coupling system, many of them for integration into OEM products. See www.fsubsea.com