Spring-loaded Temperature Sensors

Standard exhaust gas temperature sensors in 7F and 9F class turbines are at risk of premature failure due to vibrations caused by gas flows, input vibrations and thermal expansion mismatch which cause the sensor tips to break off in service.

However, Conax Technologies have recently developed their patented Spring-loaded Exhaust Gas Sensors, which have a high temperature compression spring that is inserted between two spacer tubes so that through the spring’s oscillating characteristics in dealing with stress and strain, the spring damps the vibration and keeps the temperature sensor tip stable within the radiation shield by ensuring a continuity of contact between the stop on the sheath and the seat of the radiation shield. The bushing is also fabricated of material that reduces the possibility of seizure in the radiation shield. The cold end features a ceramic insulated junction box using two different sized studs or a keyed 2-pin circular connector to guarantee proper installation every time. It also enables a convenient, stress-free orientation of the thermocouple junction box as it relates to the mating cable. This 100% hermetic thermocouple also has the latest more compatible materials to help eliminate open circuits during start up, thus eliminating false turbine trips and inconvenient down times. The new exhaust gas thermocouple has been subjected to rigorous qualification tests including vibration testing to 10 million cycles of simulated on-turbine operation, thermal cycling the measuring tip 20,000 times between 660°C and room temperature, and thermal cycling the hermetic terminal head 600 times between 370°C and -54°C, passing all OEM qualification tests and meeting all design specifications required by the OEM. The sensor is manufactured with an all welded construction that is superior to brazing in prolonging the life of the thermocouple. Available exclusively from Conax, these Spring-loaded Exhaust Gas Sensors are interchangeable with OEM parts and tested to OEM specifications. When used in 7F and 9F class turbines, these sensors have proven to significantly increase sensor life and provide thousands of hours of field operation without failures.

//