Zirconia-O2-Sensor

Supported Applications

The SST Probe Zirconia Oxygen Sensor series utilizes zirconium dioxide (ZrO₂) sensing elements to measure the partial pressure of oxygen in gas mixtures. These sensors operate without a reference gas and are designed for applications including laboratory measurements, combustion control, automotive emissions testing, oxygen generation, aerospace fuel tank inerting, agricultural processes, bakery ovens, aircraft OBIGGS systems, biomass (wood chip/pellet) monitoring, low-sulphur coal analysis, composting, boiler/furnace efficiency optimization, and controlled atmosphere monitoring.

Operating Conditions & Performance

The series measures oxygen pressure in a range of 2mbar to 3bar max with an accuracy of 5mbar max. Sensors maintain internal operational temperatures at 700°C while accommodating permissible gas temperatures from -100°C to +250°C for standard configurations and up to +400°C for high-temperature options. Response times vary by model, offering T₁₀–₉₀ < 15 seconds for standard response sensors or T₁₀–₉₀ < 4 seconds for fast response variants. The series supports gas flow rates of 0—10 m/s and requires a warm-up time of 60s prior to operation (20s from standby) with an output stabilization time of approximately 180s.

Electrical specifications include heater voltages of 4VDC ± 0.1VDC for standard response or 4.35VDC ± 0.1VDC for fast response, depending on the sensor cap and configuration. The pump impedance at 700°C is < 6kΩ. Mechanical robustness includes a repetitive permissible acceleration of 5g and an incidental permissible acceleration of 30g.

Configuration Options

The series offers multiple housing styles, mounting configurations, and termination options to suit diverse installation requirements:

• Housing Types: Available in Long Housing (Probe Series), Short Housing (Compact enclosure), Screw Fit Metric (M18 x 1.5 thread), and NPT Probe (3/4" NPT).
• Dimensions & Insertion Lengths: Overall lengths include 64.5 mm, 80 mm, 220 mm, 400 mm, and 600 mm options. Screw-fit insertion depths are available at 28mm, 45mm, or 55mm.
• Process Connections: Options include M12 x 1 thread (Long Housing), M18 x 1.5 screw mounting (Metric Probe Series), and 3/4" NPT threads.
• Electrical Interfaces: Sensors feature lead wires with PTFE insulation or a Molex Connector (part numbers 39-01-2061 plastic plug, 39-00-0041 pins). Cable termination options include blank (no cable), 0.15m, 0.3m, and 1.1m lengths.
• Operating Temperature Ranges: Configurable for -100°C to +250°C or extended high-temperature service up to +400°C (available in specific probe lengths).

Note: An external interface board is required for operation and is sold separately. Interface electronics provide output signals including digital (RS485 Modbus, RS232) or analogue (4–20mA, 0–10VDC), with measurement ranges of 0.1 - 25% or 0.1 - 100% O₂.

Key Product Differences

The series distinguishes between sensor types based on response speed and temperature capability:

• Response Time: Standard response sensors (< 15s) operate at a heater voltage of 4VDC ± 0.1VDC (1.7A). Fast response sensors (< 4s) require 4.35VDC ± 0.1VDC (1.85A).
• Temperature Ratings: Standard models support gas temperatures up to +250°C, while high-temperature variants extend this limit to +400°C.
• Housing Configurations: Long housing probes are available in 220mm, 400mm, and 600mm lengths. Short housing models provide a compact form factor (stem length 64.5 mm). Screw-fit variants offer metric M18 or NPT threading for direct installation into manifolds or flues.

All sensors in this series are RoHS compliant and utilize zirconium dioxide wetted materials. Users must avoid silicone vapours from RTV rubbers/sealants and chemical cleaning agents to prevent sensor poisoning.