Thermometrics manufactures thermocouple and RTD assemblies for gas turbine exhaust gas temperature (EGT), turbine inlet temperature (TIT), compressor discharge temperature (CDT), and inter-stage temperature measurement. Sensors are designed to survive the extreme thermal, vibration, and pressure environment of industrial and aero-derivative gas turbines.
Direct-immersion EGT thermocouples for continuous measurement of turbine exhaust temperature. Unsheathed or lightly sheathed bare-wire junction design maximizes response speed in high-velocity gas streams. MIMS construction with Inconel 600 or 625 sheath, ungrounded junction to prevent ground loop interference in multi-sensor installations.
High-temperature noble metal sensors for turbine inlet temperature measurement, where gas temperatures approach the metallurgical limit of base metal alloys. Type R or S Pt-Rh wire in alumina twin-bore insulation, housed in a refractory ceramic or Pt-Rh sheath. MIMS Pt-sheathed available for cleanest possible measurement.
Pt100 RTD assemblies for compressor inlet temperature (CIT) and compressor discharge temperature (CDT) measurement, where accuracy is critical to turbine efficiency calculations. IEC 60751 Class A, 4-wire, with flanged or threaded process connection, stainless or Inconel sheath, and spring-loaded tip for thermowell installations.
| Parameter | EGT TC | TIT TC | CIT RTD |
|---|---|---|---|
| Sensor Type | Type K or N thermocouple | Type R or S thermocouple | Pt100 RTD, IEC 60751 |
| Temp Range | 0°C to 1260°C (Type N) | 0°C to 1480°C | −60°C to 400°C |
| Tolerance | ASTM E230 Std; SLE available | IEC 60584 Class 1 | Class A (±0.15°C @ 0°C) |
| Junction Style | Ungrounded (isolated) | Ungrounded | N/A — resistive element |
| Sheath Material | Inconel 600 or 625 | Alumina tube or Pt-Rh sheath | 316SS or Inconel 600 |
| Sheath OD | 1/16" to 1/4"; custom | Per tube OD; custom | 3/16" or 1/4" |
| Process Connection | Flanged (ANSI 150–1500), NPT, welded | Flanged or brazed boss | NPT, flanged, compression |
| Vibration Rating | Per ISA-67.04 / OEM specification | Per OEM qualification | MIL-STD-810 on request |
| Documentation | AS9100D, FAIR per AS9102, NIST cal | NIST ITS-90 traceable | AS9100D, C of C, NIST cal |
Gas turbine EGT measurement typically uses a multi-sensor rake or harness with 8–16 thermocouple elements distributed around the exhaust annulus. Each element is individually calibrated and wired to a dedicated channel of the turbine control system. Thermometrics supplies complete EGT harness assemblies with individual MIMS tails, common mounting flange, and thermocouple extension cable or circular connector for control cabinet termination. See the TC Rake Assembly page for complete specifications.
MgO-insulated metal-sheathed cable is the only thermocouple construction capable of withstanding the continuous broadband vibration of a gas turbine casing. Wire-wound elements in ceramic insulation will fracture. MIMS cables have no internal mechanical joints susceptible to vibration fatigue.
With 8–16 sensors in a single EGT harness, a grounded junction in any sensor creates a parallel electrical path through the turbine structure. Ungrounded (isolated) junctions eliminate this source of measurement error and simplify fault diagnosis.
Inconel 625 provides superior resistance to oxidation and sulfidation at elevated temperatures compared to Inconel 600, and is the preferred sheath material for turbines burning fuel with elevated sulfur content or wet steam injection.
EGT measurement accuracy directly affects fuel efficiency calculations and hot-section inspection intervals. Thermometrics offers Type K and N MIMS cable with Special Limits of Error wire (approximately ±0.4% of reading vs ±0.75% standard) to improve absolute temperature accuracy across the fleet.
All gas turbine sensor orders are processed under the Thermometrics AS9100D quality management system. First Article Inspection Reports (FAIR) per AS9102, material certifications, and NIST-traceable calibration certificates included with every order.
Thermometrics provides repair and recertification services for EGT harness assemblies removed from service. Individual elements can be replaced, re-sheathed, and recalibrated without replacing the full harness. AS9100D documentation issued on repaired assemblies.
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