Seals for Airborne Electro-Optical Systems

For Infrared Devices and Surveillance Cameras

Airborne electro-optics such as forward looking infrared devices and surveillance cameras are used in an ever-growing variety of military, law enforcement, and civilian activities.

Applications include:

• Target acquisition and designation
• Weapons guidance
• Forward-looking infrared (FLIR) devices
• Reconnaissance and surveillance

Performance

Ferrofluidic seals permit delicate electro-optical instruments to operate at their maximum potential under highly demanding airborne conditions. Hermetic seals allow smooth, damped rotation in azimuth and elevation while maintaining a clean, constant pressure environment within the optical pod. The innovative magnetic fluid-based seals can integrate many additional features such as bearing assemblies and customized interfaces to form low-maintenance, highly integrated sealed gimbal systems in nearly unlimited combinations of diameters and sizes. Extremely low, consistent drag torque consumes very little servomotor power. Ferrofluidic seals are specified for airborne enclosures in which superior dynamic sealing is critical for optimum optical performance.

Benefits:

• True hermetic sealing
• High reliability
• Zero maintenance
• Low drag torque
• Wide thermal range
• Smooth operation
• Flexible configurations
• Compliance to military specifications and standards

Leak-Free Sealing of Airborne Optics

Styles of movable camera pods include single axis and gimbaled multiple axis. Both require a sealed interior chamber containing a moisture-free gas. The dynamic sealing system must maintain this internal environment while the aircraft is subjected to dust, rain, aircraft fuels, de-icing spray and normal maintenance fluids, under a variety of outside temperatures and altitudes.

Ferrofluidic seals provide hermetic sealing while allowing smooth, low-power rotation. Traditional elastomer lip seals and mechanical seals cannot provide adequate sealing or dependable, long-term performance. Retrofitting these older sealing methods with Ferrofluidic magnetic fluid seals dramatically improves equipment operation.

Gimbal Style Optical Pods (multiple axis)

Multiple axis scanning pods (as shown below) use Ferrofluidic seals to achieve smooth optical tracking in both azimuth and elevation. These pods are under-wing mounted or installed in the nose area to provide maximum forward-looking area. Ferrofluidic seals are ideal for these applications as they have extremely low drag torque throughout a wide temperature range.

Single Axis Optical Tracking Systems

The optical pod is mounted under a wing or on a lower fuselage surface and scans about a single axis as the aircraft approaches a target. A seal is installed at each end of the movable optical pod where it interfaces with a stationary mounting bracket. The Ferrofluidic seal has a large internal passage for cables, pressurization and optical path. The seal has a small radial section, and includes precision ball bearings that fully support the rotating assembly to form a low-drag sealing assembly for differential pressures exceeding one bar (14.5 psi).

The seal provides leak-free performance and long, maintenance-free operation. Options for this particular arrangement include higher pressure capability (up to 500 psi), exotic lightweight materials, seal heating or cooling with feedback for extreme environments, and additional system features for tighter dimensional requirements and lower system costs.

Customized Airborne Sealing Systems

Ferrotec has extensive experience integrating innovative sealing technology with bearings and other features into cost effective, high performance subassemblies. Ferrofluidic seals can be designed to fit into existing housings or a completely new assembly can be produced.

Ferrotec offers:

• Research and development through design, manufacturing and ongoing customer support
• Operation verification and testing of airborne optical pods in proven compliance with military specifications
• Aircraft grade lightweight materials fabrication
• Ferrofluid development to meet specific temperature, environmental and sealing conditions