OXYFIRE™ - Nitrex
Close this search box.





The Oxyfire™ in-situ oxygen sensor measures oxygen concentrations directly in the “high heat” zones of high temperature furnaces, boilers and incinerators. This sensor series is intrinsically safe, requires no electrical input power and generates only a low millivolt output.



  • Available in several standard lengths up to 48″ (1,200 mm)
  • Field performance can be easily verified using integral verification gas port
  • “B,” “S,” and “R” thermocouples are available
  • Alumina, silicon carbide, HR160 alloy and zirconia protection sheaths are available
  • CE marked
  • Intrinsically Safe under EN50 014 (1977) clause 1.3
  • Temperature range: 1,000 °F – 3,000 °F (max) / 538 °C – 1,649 °C (max)
  • Robust design eliminates “auxiliary sheaths” required on lower quality products
  • Single side connections ensure cables are safely away from the hot furnace wall
  • Compatible with standard conduit fittings
  • Proven track record: used in more furnaces, boilers and incinerators than all other high-temp probes combined
  • Longest life available
  • No drift or accuracy problems common to “side hole” probes
  • High quality construction eliminates the need for cooling air (another failure point in low-end designs)
  • Patented “boot” provides fast response while protecting the outer electrode and preventing accuracy problems that plague foil-based electrodes
  • Proprietary, application-specific installation configurations maximize life and accuracy in high-slag environments
  • Machined 6061T6 aluminum head provides airtight enclosure for electrical connections
  • Classified configurations available
  • 12-month warranty


Net O2 range:PPM to 21%
Accuracy:1.5% of observed process variable or 0.5% O2, whichever is greater
Control system interface:UPC Protherm 20 or Oxymit Transmitter
Response time:Less than one second for 98% of final value
Stability:Less than 1% deviation in signal output over the life of sensor
Temperature limits:
Process550-1,600°C (1,022-2,912°F)
Terminal headAmbient to 149°C (300°F)
Mounting:Vertical or horizontal
Inner tubeZirconia
Outer protection sheathAlumina, Silicon carbide, HR-160 high temperature alloy
Sensor headAirtight, machined 6061-T6 aluminum
Integral T/CType “B” standard, “R” and “S” optional
Sensor insertion lengths:6”, 12”, 18”, 24”, 30”, 36”, 42”, 48” (non-standard) (≈ 15 cm, 30 cm, 46 cm, 61 cm, 76 cm, 91 cm, 107 cm, 122 cm)

*The Oxyfire oxygen sensor is a “simple apparatus” and thereby intrinsically safe per EN50 14 (1977) Clause 1.3.

Still Have questions?

Can’t find what you’re looking for? Please feel free to get in touch with our experts.