Amagnetic Pumps

Amagnetic pumps for naval, defence and offshore environments

DESMI’s amagnetic pumps are intended for applications where conventional pump construction may not be acceptable due to magnetic-permeability limits, stealth requirements or the need to avoid magnetic interference with sensitive systems. In these environments, the pump is not only a hydraulic component. It is also part of the platform’s broader operational and survivability design.

For naval and defence applications, this often means a mechanically driven pump built from carefully selected materials that support magnetic neutrality, corrosion resistance and structural reliability under harsh operating conditions. Depending on the duty, the pump may also need to address vibration, pressure fluctuations, thermal cycling, submergence-related considerations or shock survivability.

DESMI supplies pumping solutions for marine and defence installations worldwide, including project-specific designs for essential shipboard functions. Amagnetic execution is a specific technical requirement within this broader portfolio - not a general feature of all naval pumps. Where required, selected designs can be supplied as low-magnetic-signature solutions for ships, submarines and defence infrastructure.

The Difference Between Amagnetic and Magnetic Drive Pumps

A clear technical distinction is important: amagnetic pumps are not magnetic drive pumps.

An amagnetic pump is defined by the magnetic neutrality of its construction. In practice, this means that magnetic components are replaced, reduced or avoided through the use of non-magnetic materials and configuration choices designed to minimise magnetic signature. The objective is to support low-signature vessel or installation requirements.

A magnetic drive pump, by contrast, is defined by its method of torque transmission. It uses a permanent-magnet coupling to transfer torque from the motor to the impeller without a conventional shaft seal. This is a different pump concept designed for different process and containment priorities. Because permanent magnets are an active part of the drive arrangement, magnetic drive technology is not the same as amagnetic construction.

For this reason, the terms should not be used interchangeably:

• Amagnetic pump = a pump designed for magnetic neutrality or low magnetic signature.

• Magnetic drive pump = a pump that uses permanent magnets for torque transfer.

Selected DESMI amagnetic pumps use a mechanically coupled drive arrangement rather than a magnetic coupling. This helps maintain the intended low-magnetic-signature design philosophy while providing the mechanical integrity needed for marine and defence service. Where a project includes magnetic-signature limits or magnetic-permeability thresholds, the full pump configuration and associated verification requirements should always be confirmed for the specific installation.

Applications Across Naval and Defence Systems

Amagnetic pumps are typically specified where low magnetic permeability or reduced magnetic signature forms part of the system requirement. Within naval and defence systems, relevant applications can include cooling water duties, service systems, submarine circulation, fuel transfer, and selected fixed or mobile defence infrastructure.

Typical use cases include:

• Cooling water and auxiliary service systems on naval vessels

• Submarine circulation systems where low-signature equipment is required

• Fuel transfer systems subject to material, safety and magnetic-signature criteria

• General service duties in defence platforms

• Selected pump installations in military infrastructure and support facilities

• Projects requiring Military Off-The-Shelf pump integration or MOTS pump documentation

Suitability depends on the selected hydraulic design, drive arrangement, materials, duty point, installation envelope and qualification requirements. Not every service on a naval platform requires amagnetic execution, and not every pump type within a defence system will be supplied as non-magnetic. DESMI therefore assesses each application individually based on the fluid, operating conditions, pressure class, corrosion exposure, magnetic requirements and any shock or vibration criteria defined by the project.

Key Benefits of DESMI Amagnetic Pumps

The main value of amagnetic pumps lies in their ability to address a combination of operational, material and procurement requirements that are common in naval and defence programmes. Rather than offering one single advantage, they support a broader low-signature and high-reliability system strategy.

• Reduced magnetic signature - selected designs are built to minimise the pump’s contribution to the overall magnetic signature of the vessel or installation.

• Mechanically dependable operation - mechanically driven arrangements support stable operation in continuous-duty marine and defence environments.

• Corrosion-resistant material choices - material selection can be aligned with seawater, fuel, cooling fluids and other media, subject to compatibility and project requirements.

• Shock-rated design options - selected versions can be engineered for naval shock requirements where survivability under specified shock conditions is part of the scope.

• MOTS compatibility - DESMI can support military procurement needs with Military Off-The-Shelf pump configurations and associated documentation requirements, where applicable

• Maintainability and lifecycle support - long-term service, spare parts and traceability support are important for critical defence assets with extended operating life.
  
  

These benefits should be judged against the exact duty and qualification scope. For defence buyers and naval architects, the key advantage is often not only pump performance, but also the ability to combine low magnetic signature, application-specific materials, maintainability and project documentation in one coordinated solution.

Engineering design and material selection

DESMI amagnetic pumps are based on mechanically coupled pump designs developed for reliable service in demanding environments. The exact arrangement varies by application, but the design approach typically focuses on stable rotor dynamics, controlled hydraulic performance, structural integrity and material selection matched to both the fluid and the magnetic requirements.

Core design principles may include:

• Mechanically coupled drive arrangements for robust torque transmission

• Dynamically balanced impellers to support stable running characteristics

• Precision-machined housings and internal components

• Shaft and bearing arrangements designed for dependable operation

• Inline or base-mounted configurations, depending on system layout

• Configuration-dependent selection of non-magnetic stainless steels, titanium, bronze alloys or composite materials, where appropriate
  
  

Material selection is never generic. It depends on the actual service conditions and specification boundaries, including:

• Fluid chemistry and contamination level

• Operating temperature and pressure

• Corrosion and erosion exposure

• Required magnetic permeability or signature limits

• Shock and vibration requirements

• Classification and programme documentation needs

In practice, this means a pump intended for seawater circulation may require a different build from one intended for fuel transfer or closed-loop cooling service. Selected DESMI solutions can therefore be engineered around the specific combination of hydraulic duty, material traceability, structural demands and low-signature requirements defined by the customer or end user.

Amagnetic pumps and shock-rated pump requirements

Amagnetic pumps and shock-rated pumps address two different technical demands, although they may overlap in the same project. An amagnetic pump is concerned with magnetic neutrality and low magnetic signature. A shock-rated pump is concerned with survivability and continued operation when subjected to defined mechanical shock conditions, such as those associated with naval service. One requirement does not automatically satisfy the other.

For naval platforms, both can be relevant at the same time. A pump may be required to contribute as little as possible to the vessel’s magnetic signature while also being capable of withstanding specified shock loads before, during and after a shock event. In such cases, the engineering task involves more than material selection. It can also involve casing design, support arrangements, shaft integrity, bearing support, rotor stability and project-specific qualification testing.

Selected DESMI solutions can be engineered to support both low-magnetic-signature requirements and naval shock survivability, depending on the chosen configuration. This is particularly relevant for critical systems on combat ships, submarines and auxiliary naval vessels where operational continuity matters. However, the applicable shock level, test method and acceptance criteria must always be confirmed for the individual project rather than assumed across the full product range.

Standards, qualification testing and MOTS documentation

Naval and defence procurement typically requires more than a performance curve. Buyers often need documented evidence covering materials, manufacturing traceability, test scope, configuration control and conformity with platform-specific requirements. That is where project documentation and qualification planning become central to pump selection.

DESMI can support Military Off-The-Shelf requirements where a standard or adapted pump design is to be integrated into a defence platform as a Military Off-The-Shelf pump solution. Depending on the selected configuration, pumps can be supplied in designs tested to, or engineered in accordance with, relevant naval, military and classification-related requirements.

Applicable references may include project-specific requirements associated with:

• MOTS or Military Off-The-Shelf pump procurement

• MIL-S-901D shock testing for selected designs

• Vibration and structural integrity verification

• Pressure testing and mechanical performance checks

• Noise and vibration assessment where specified

• Material certification and traceability documentation

• Classification-related requirements from bodies such as ABS, DNV or Lloyd’s Register, where relevant to the project

It is important to state this accurately: not every amagnetic pump is automatically certified to every naval or military standard. Compliance depends on the exact pump configuration, the required test level and the project scope. DESMI therefore works with customers to define the documentation package, qualification route and evidence required for the individual procurement process.

Typical buyer documentation requests may include:

• Product datasheet and duty-point confirmation

• Performance curve and operating limits

• Material certificates and traceability records

• Magnetic-permeability or magnetic-signature verification, where required

• Shock and vibration test evidence for the covered configuration

• Installation, maintenance and spare-parts documentation

Operation, maintenance and lifecycle support for amagnetic pumps

For defence and naval operators, long-term support is often as important as the initial pump specification. Critical systems may remain in service for many years, and maintenance planning, spare-parts access and documentation control all affect readiness and total cost of ownership.

DESMI supports amagnetic pump installations with technical guidance throughout the equipment lifetime. This can include commissioning support, spare parts supply, service agreements, planned maintenance and engineering assistance related to operation, inspection and replacement planning. The objective is stable operation and predictable support for assets where downtime or configuration uncertainty may have wider operational consequences.

Lifecycle support may include:

• Commissioning and installation support

• Planned maintenance recommendations

• Original spare parts and replacement planning

• Service agreements for long-term asset support

• Technical documentation and revision control

• Guidance on material compatibility and service conditions

For naval and defence programmes, documentation and traceability can be especially important. DESMI therefore supports customers with the technical records needed to maintain continuity across maintenance cycles, refits and procurement updates. You can learn more about after-sales service and lifecycle support.