Customizing Hermetic Electrical Feedthroughs for Optimal Performance

Hermetic electrical feedthroughs often require more customization than simply hermetically sealing the conductors or optical fibers within a mechanical housing.  At Douglas Electrical Components, it requires various steps in the process of developing a solution that is Design for Manufacturing-ready and suitable for the application’s environment. Customers partner with our sales engineers to review the product and application requirements. This is a thorough process to ensure all performance specifications can be met while surviving any mechanical or electrical specifications, from hazardous locations to MIL-spec requirements. Our sales engineers have extensive backgrounds in hermetics, mechanical, and electrical engineering to support the various design criteria for a given application. After establishing the baseline, our team will work to understand the scope of the application beyond the feedthrough to see if value-added assembly work would benefit the customer and the application.

Feedthrough Example

In this feedthrough example, an automotive customer was designing a hermetic electrical feedthrough suitable for a pressurized environment. Various mechanical and electrical features were added to this assembly to meet the application conditions while simplifying the installation and utilization of the feedthrough.

 

This design features a radial O-ring feedthrough housing with a top hat configuration and O-ring seal. This type of housing is very common in OEM applications requiring quick installation with a high-pressure hermetic seal. The retaining ring groove extends past the bulkhead to install a snap ring. This type of housing is suitable for pressures up to 15,000 PSI (1,000 Bar).

 

Douglas employs hermetic epoxy for its hermetic seals. This is a chemically inert material that offers low outgassing. Epoxy permits a high density of conductors through the housing with a complete hermetic seal to the conductor.

 

PTFE (Teflon) conductors were chosen for this application. The conductors are then protected by a fiberglass wire sleeving for a more robust packaging for the application environment. Douglas offers other types of sleeving and armor that can be added and potentially grounded within the hermetic feedthrough assembly or simply over the conductors like this design.

 

An FKM (Viton) shrink tube was integrated into the assembly. While the wires and PCB are not part of the feedthrough, Douglas pre-installed the wires and sleeve to simplify installation at the customer end. The wires are terminated in a plug-and-play connector which also includes the conductors from the feedthrough. Douglas employs other designs through our CircuitSeal series, where a PCB or flex circuit is encapsulated within the housing.

 

More Value-Added Capabilities:

• Connectorized wire and cable feedthrough assemblies
• Full cable harnessing with hermetic properties for turn-key installation including braided or spiral shielding
• Directly integrate existing connectors, wires, cables, and termination boxes
• Hermetically sealing of customer-furnished mechanical and electrical connections
• Bundle mating cables, assemblies, and harnesses to reduce suppliers