Circular Hermetic Connector features thermocouple contacts.

Press Release Summary:

Available in EN 2997, MIL-DTL-38999 Series III and EN 3646 versions, Circular Hermetic Connector is fitted with pair of nickel-chrome/nickel-aluminium contacts. Suitable for aircraft, military equipment, harsh environments applications, unit comes with glass insulator and sintered pad. 

Original Press Release:

Esterline Connection Technologies – SOURIAU's Series of Hermetic Connector now Features a Version with Thermocouple Contacts

Esterline Connection Technologies – SOURIAU announces that its range of circular connector with thermocouple contacts now includes a version with hermetic receptacle to meet specific requirements for aircraft, military equipment, and applications in harsh environments.

This connector range supplements and complements SOURIAU's current range of hermetic connectors and thermocouple contacts. The specific thermocouple contacts can be fitted in connectors that comply with EN 3646, MIL-DTL-26482, MIL-DTL-38999, and EN 2997. In civil and military aviation, for example, they are used to connect temperature sensors placed around aircraft engines and brake systems.

A specific contact technology

In temperature measurement chains, nickel-chrome (NiCr) and nickel-aluminium (NiAl) are soldered at the sensor inside the transducer and must have material continuity up to the analysis electronics. A connector's contacts must meet this requirement in order for it to be added to the measuring chain. SOURIAU ensures material continuity by fitting a nickel-chrome contact and a nickel-aluminium contact in each of its thermocouple connectors, thus rendering them neutral in the measuring chain.

Hermetic contacts and receptacles

Receptacles fitted on equipment must be hermetic at two points. The first point relates to the method used to attach the receptacle, which is possible by laser or TIG welding or by fitting a special O-ring. The second point is at the contacts inside the receptacle. Here, the conventional insulator is replaced by a glass insulator. A sintered pad of the same size as the shell and corresponding to the contact layout is inserted and melted at 1000°C in an autoclave. The heating and cooling cycles in the process are interspersed with stabilization periods. As a result, the glass contracts to form a fully hermetic seal within the shell and around each contact. Each connector undergoes rigorous quality control in the form of a helium leak test in order to guarantee the specific leakage rate of less than 10-7 atm-cc/sec required for hermetic connectors.

Contact layout and arrangement

Most connectors are fitted with a pair of nickel-chrome/nickel-aluminium contacts to form a thermocouple pair. SOURIAU can provide connectors with two pairs or more of thermocouple contacts for customers that require signal acquisition redundancy.

Two standard arrangements of three and five contacts are available based on standard definitions. As in any hermetic connector, the matching contacts are typically made of ferronickel.

SOURIAU can customize the location of contacts inside the cavity to the customer’s requirements.

Available connectors

SOURIAU's hermetic connectors with thermocouple contact are now available in three versions: EN 2997, MIL-DTL-38999 Series III, and EN 3646.They are the perfect match with SOURIAU's existing range of hermetic connectors and removable contacts designed for use in increasingly harsh environments.


SHAW Rhonda


25 Grumbacher road

York PA 17402

Phone : 1 866 768 7428

Fax : 1 717 505 5953

MOREAU Ludivine

Esterline Connection Technologies


Phone: +33 1 30 84 28 84

Fax: +33 6 32 82 40 37

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