Aerospace & Defence

Fluid sealing products for Aerospace and Defence Industry

M. Barnwell Services supplies critical seals for use in both Aerospace and Defence. All products meet the standards required for these industries.

We are continuously researching, designing, enhancing and distributing a diverse range of parts that are critical to the NATO (stock numbers NSN) and are able to provide, on request, military specification seals including: NES 337 (Naval Standard) UK Ministry of Defence (MOD), AS9100 Rev.C, AMS, AS, AN, M, MS, MIL, NAS, EN, NFL and DEF STAN. Bespoke O Rings and special mouldings can be produced to meet the specific requirements of your application.

More certifications and standards include EN9100: Quality management in aviation, ISO 2685 and AC20-135: Fire protection aviation, Nadcap, REACH and RoHS: Environmental protection, and ITAR Capabilities.

Challenges for Aerospace & Defence Industry

The Aerospace and Defence Industry presents some of the most demanding challenges for sealing technology due to extreme operating environments and conditions and the the critical nature of applications.

Extreme Environment

Seals in this industry must perform reliably under conditions that rapidly cycle between extreme:
- Temperature – Seals must maintain integrity in high altitude (as low as $- 26 8^{\circ} C$ / $- 45 0^{\circ} F) to jet fuel heat (over 300^{\circ} C / 572^{\circ} F)$
- Pressure – Hydraulic systems for landing gear and flight control operate at extremely high pressures, often over 5000psi. Seals must be designed to prevent extrusion without generating excess friction
- Motion – These seals are often subjected to constant, high-frequency vibration and high-speed reciprocating/rotary motion. This can lead to accelerated wear and friction

Operational/Design Requirements

Due to the need to maximise fuel efficiency, every component in an aircraft/spacecraft must be as lightweight as possible
A critical issue is to ensure there is zero leakage of oil. This failure can cause cabin depressurisation which is a major health and safety concern.
High friction in dynamic seals wastes energy, generates heat that degrades the seal and causes rapid wear. Seals designed with low-friction materials, such as PTFE, extend operational life
Hermetic Seals seals are used to provide an airtight, gas-tight seal to prevent moisture and contaminants from damaging highly sensitive electronic systems

Safety, Regulation and Maintenance Concerns

All seals used in Aerospace and Defence applications must meet extremely strict industry standards and military specifications for fire resistance, material properties and performance
Elastomeric seals are susceptible to embrittlement and loss of resilience if they are stored improperly or used beyond their shelf life.

These challenges are being combated by focusing on innovative seal designs and latest manufacturing techniques to ensure reliability under increasingly extreme operating conditions.

Using the newest and most advanced materials, looking beyond traditional sealing solutions and continuously researching the latest in industry advancements allows for sealing technology to be continuously developed and refined.

Aerospace and Defence materials

Bonded Seals

Bonded seals (also known as Dowty seals) or washers, are used in the Aerospace & Defence Industry to create a reliable, leak-proof seal between two surfaces, typically in hydraulic or pneumatic systems. They are designed to prevent fluid or gas leakage in high-pressure environments which is critical in this industry, where safety and performance are principle.

Bonded seals/Sealing washers are used to seal joints in hydraulic systems that operate under high pressure, ensuring there are no fluid leaks, as well as preventing leaks in fuel lines and connections. The pressure they are able to withstand is dependant on the size and material chosen. Temperatures range from -30°C to 100°C for NBR Rubber seals and -15°C to +200°C in the case of FKM seals.

Further information on Specialist Products

NATO Stock Numbers List – Oil Seals
NATO Stock Numbers List – O Rings

Sealing Washers – British Imperial Standard range
Sealing Washers – German Metric Standard range
Sealing washers – French Metric range

AMS Rubber Specification – O Rings

Find out more about our specialist range of Aerospace Compliance Seals.

Sealing Solutions

Defence

Combat Drones – sensors, actuators in unmanned systems, sensitive electronics
Defence Systems – Missile launchers, GPS guidance systems
Communication Systems – Radar systems, sensors, controls panels, communication equipment
Weapons and Ammunition – Firearms, missiles, guided ammunition
Ground vehicles – Armoured (tanks), trucks, suspension systems, transmission components
Aircraft – Hydraulic actuator systems, engines, fuel compartments,
Submarines and Naval vessels – Sonar systems, propulsion

The role of seals in these systems is critical for ensuring the reliability and safety of mission-critical systems across air, land and naval applications. These components create essential barriers to exclude contaminants such as dust and moisture, contain operational fluids including fuel and hydraulic oil whilst maintaining pressure in demanding environments. Seals are essential for preventing equipment failure in extreme operational conditions

Aerospace

Control surfaces and Flight systems – flaps, rudders, ailerons, control cables
Avionics & Electronics – Sensors, connectors, Avionics
Hydraulic & Pneumatic systems – Hydraulic actuators, valves and cylinders
Landing Gear systems – Shock absorbers, brakes, landing gear actuators
Spacecraft – Missile systems, satellites, pressure vessels
Engines & Fuel systems – Jet engines

The Aerospace industry critically depends on precision seals to ensure safety, reliability and optimal performance of aircraft and spacecraft. Seals are vital for preventing leakage of pressurised fluids and gases in engines, landing gear and high-pressure hydraulic systems whilst also maintaining cabin pressure at high altitudes. Operating under extreme challenges from cryogenic temperatures of fuel tanks to intense heat of jet engines as well as the damaging effects of UV radiation require Aerospace seals to be lightweight and conform to strict industry standards to prevent catastrophic failure.

Popular products supplied include:

Packaging, industry standard and bespoke solutions are offered.

When it comes to quality fluid sealing products we are one of the most reliable sources in the industry.

We can also provide onsite consultation, sample identification and technical support for your requirements.