SST Sensing’s zirconia oxygen sensors offer a reliable, long-term solution for measuring oxygen levels in demanding industrial environments. With robust solid-state construction and high accuracy across a wide oxygen range, they are well suited for combustion control, emissions monitoring, inert atmosphere systems, and more.
Explore SST’s zirconia oxygen sensor portfolio to find the sensor and interface combination best suited to your application requirements. This page combines technical details to support engineering decisions and help guide sensor selection.
Understanding the Range
Although all SST zirconia oxygen sensors use the same sensing cell technology, they differ in housing design, cap structure, response times, and temperature handling. These variations allow you to select a sensor that precisely meets your system’s environmental and mechanical requirements.
A key feature to consider is the sensor cap, which affects how quickly the sensor responds to changes in oxygen concentration. Sensors fitted with a full porous cap allow gas to diffuse from any angle, enabling a fast response time of under 4 seconds.
Alternatively, sensors with a porous lid cap restrict gas entry to the top face only, resulting in a standard response time of under 15 seconds. This choice typically depends on the gas flow dynamics in your application.
Another important consideration is the sensor housing. SST manufactures four main formats: flange mounted, miniature, probe type, and screw fit. These are described below to help you match sensor form to your system’s physical and environmental constraints.
Zirconia Sensor Types
Flange Mounted
This sensor is designed for easy sealing into manifolds or sampling chambers. It offers a fast response time (<4 seconds) and supports gas temperatures from –100°C up to 400°C. Its robust construction and flange mounting make it ideal for aerospace systems and any application requiring temperature or pressure integrity.
Miniature
Engineered for compact designs, the miniature sensor is suitable for PCB integration. Depending on the cap used, it supports standard or fast response performance, with operating temperatures up to 250°C. It’s commonly used in ambient air monitoring or portable gas detection systems.
Probe Type
Probe sensors are available in three standard lengths—80 mm, 220 mm, and 400 mm—allowing measurement at different depths or through thicker flue walls. The design supports a wide gas temperature range (up to 400°C depending on the variant), and can be supplied with a standard or fast response cap. This format suits applications requiring deeper gas access, such as industrial combustion control.
Screw Fit
This sensor features a threaded body for simple and secure installation into flue gas streams or combustion chambers. It offers a quick response time and supports high-temperature operation. Probe insertion depths are available in 28 mm, 45 mm, or 55 mm. It is widely used in boiler optimisation and closed-loop combustion systems across coal, gas, oil, and biomass applications.
System Integration and Interface Options
SST provides interface boards and analyser systems to operate and read from its zirconia sensors. The OXY-LC and O2I-FLEX boards provide compact, configurable solutions where flexibility is key, while the OXY-FLEX Oxygen Analyser offers a fully integrated measurement system with onboard signal output.
When choosing an interface, it’s essential to define your required oxygen measurement range (typically 0.1–25% or 0.1–100%), preferred output type (analogue 4–20 mA or 0–10 VDC, or digital RS232/RS485 Modbus), and your layout constraints. For optimal performance, keep cable lengths between the sensor and interface as short as practical, as this ensures stable heater voltage and reduces electrical noise.
Environmental and Application Factors
Your sensor selection should also reflect the environmental conditions it will face. These include gas composition, operating pressure, temperature, humidity, and whether the gas is corrosive or high in moisture. Understanding the exact application environment helps ensure you choose a stable and accurate sensor over the long term.
Mechanical installation also plays a role. For example, if space is limited or sealing is critical, a miniature or screw-fit sensor may be more appropriate than a probe or flange-mounted option. Consider where the interface board will be housed—will it require environmental protection, and how accessible does it need to be for calibration?
Engineering Support and Custom Options
While SST’s standard sensor portfolio suits various applications, custom solutions are available. Suppose your project requires a non-standard housing, special heater voltage, or an alternative integration format. In that case, our engineers are happy to help evaluate your requirements and recommend or develop a customised sensor.
Sensor Types
The ZrOâ‚‚ sensor range includes four core types: Flange Mounted, Miniature, Probe, and Screw Fit. Below is a brief summary of each variant and its typical use..
Flange Mounted Oxygen Sensor
| Response Time | < 4 seconds (fast) |
| Heater Voltage | 4.35 VDC |
| Gas Temperature Range | –100°C to +400°C |
| Mounting Style | Flange-mounted |
| Applications | Aerospace, high-pressure systems |
Miniature Oxygen Sensor
| Response Time | <15 sec (standard), <4 sec (fast) |
| Heater Voltage | 4V (standard), 4.35VDC (fast) |
| Gas Temperature Range | –100°C to +250°C |
| Mounting Style | PCB-mounted |
| Applications | Ambient gas measurement |
Probe Oxygen Sensor
| Response Time | <15 sec (standard), <4 sec (fast) |
| Heater Voltage | 4V (standard), 4.35VDC (fast) |
| Gas Temperature Range | –100°C to +250°C / D13: –100°C to +400°C |
| Mounting Style | 80mm, 220mm, or 400mm probe lengths |
| Applications | Flue monitoring (thick walls) |
Screw Fit Oxygen Sensor
| Response Time | <4 seconds (fast) |
| Heater Voltage | 4.35VDC (4.55VDC BM range) |
| Gas Temperature Range | –100°C to +250°C |
| Probe Insertion | 28mm, 45mm, or 55mm |
| Mounting Style | M18x1.5 thread, 75mm total |
| Applications | Boiler efficiency, atmosphere control |
All of our oxygen sensors require interface electronics to operate. You can find details for these products on the following links;
OXY-LC Interface Board and ; O2I-FLEX Interface Board
Need a Custom Solution?
If your application falls outside these options, SST can customise the sensor’s mechanical design, electronics, or output configuration to meet your requirements. Our team works closely with industry engineers to ensure accurate integration and long-term performance.
Explore the full zirconia product range or get in touch with our technical team for tailored advice: ; Oxygen Zirconia Sensors
To discuss your application or for more information please contact one of our highly trained engineers today.
