Product Overview

High-Pressure Thermocouple & RTD Assemblies for Severe Process Boundaries

High-pressure temperature assemblies are specified around the pressure boundary first, then the sensing element, process connection, seal design, sheath material, and documentation package required by the installation.

High-Pressure Sensor Boundary Design

These assemblies are used where a sensor failure can become a process-containment problem. The visual highlights the heavier process interface, protected transition, and field-service geometry common to wellhead, reactor, and severe-duty installations.

High-pressure thermocouple assembly with heavy machined pressure fitting, long probe, and armored lead exit

Severe-Duty Process Assembly

Use this geometry when the sensor interface is part of the pressure boundary in subsea, wellhead, reactor, or other severe-duty service.

Pressure Boundary and Seal Considerations

Critical Seal Selection

At pressures above 5,000 PSI, elastomeric seals may extrude under thermal cycling. Higher-pressure assemblies that use metal-to-metal cone seals provide a more reliable pressure barrier that does not degrade under repeated thermal cycles. All high-pressure assemblies are hydrostatically tested at 150% of their maximum allowable working pressure (MAWP) before shipment. Test certificates are issued with every unit.

NACE MR0175 / Sour Service

Sheath Material

Corrosion-resistant sheath alloys for sour service, typically Alloy 825 or Hastelloy C276.

Hardness Limit

Material hardness controlled to 22 HRC or below in accordance with NACE MR0175 requirements.

Certification

Material test report and traceable MTR documentation supplied for compliance review.

H2S Rating

Sour-gas suitability confirmed against ISO 15156-3 for hydrogen sulfide service conditions.

Subsea and Severe-Duty Build Notes

Subsea Applications

Subsea high-pressure assemblies are designed for installation on production trees, flowlines, and manifolds. Wet-mate connector systems allow installation by ROV without breaking the pressure barrier. Depth ratings to 3,000m are available, with galvanic compatibility analysis performed for subsea assemblies.

Documentation and Testing

Severe-duty builds are typically reviewed around pressure rating, process compatibility, material traceability, hydrostatic test documentation, and the installation method required by the pressure boundary.

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