This is now our 26th consecutive week of SST’s #SensorFAQs series which you can join in and follow on our twitter page.
We’ll be sharing Frequently Asked Questions we receive from our customers to help provide expert insights into our product range, the sensor industry and more.
This week we answer ‘ How can I prolong the life of my Zirconium dioxide oxygen sensor?’
Details for next weeks #SensorFAQs:
Date & Time: Tuesday, 5th November 2019, 1.00pm GMT
Channel: #SensorFAQs
#SensorFAQs – Q26 | How can I prolong the life of my Zirconium dioxide oxygen sensor? pic.twitter.com/1mwkezqiGO
— SST Sensing Ltd (@SSTSensingLtd) October 29, 2019
Answers
#SensorFAQs – Q26 1/12 | The application in which the zirconia oxygen sensor is operating influences the life of the sensor. To ensure the sensor does not fail prematurely, the following should be considered: https://t.co/o0ByX4dHu7
— SST Sensing Ltd (@SSTSensingLtd) October 29, 2019
#SensorFAQs – Q26 2/12 | Fail-Safe Operation and Sensor Asymmetry
One of the main benefits of the dynamic and active cell employed within the oxygen sensor is that it is inherently fail-safe. The continual cycling and measuring of the generated Nernst voltage is effectively… https://t.co/o0ByX4dHu7
— SST Sensing Ltd (@SSTSensingLtd) October 29, 2019
#SensorFAQs – Q26 3/12 | …the heartbeat of the sensor, if this stops something fatal has occurred within the cell. This can very quickly be detected by the interface electronics. https://t.co/o0ByX4dHu7
— SST Sensing Ltd (@SSTSensingLtd) October 29, 2019
#SensorFAQs – Q26 4/12 | Operating in Aggressive Humid Environments
When operating the zirconia oxygen sensors in warm, humid environments it is important the sensor remains at a higher temperature than its surroundings, especially if there are corrosive components in the… https://t.co/o0ByX4dHu7
— SST Sensing Ltd (@SSTSensingLtd) October 29, 2019
#SensorFAQs – Q26 5/12 | …measurement gas. During operation this is less of an issue as the heater operates at 700⁰C, however this means when the sensor or application is being powered down the sensor heater must be the last thing to be turned off after the temperature of… https://t.co/o0ByX4dHu7
— SST Sensing Ltd (@SSTSensingLtd) October 29, 2019
#SensorFAQs – Q26 6/12 | …the surroundings have suitably cooled. Ideally the sensor should be left powered or at a lower standby voltage (2V typically) at all times in very humid environments. https://t.co/o0ByX4dHu7
— SST Sensing Ltd (@SSTSensingLtd) October 29, 2019
#SensorFAQs – Q26 7/12 | Protecting from Excessive Moisture
In environments where excessive moisture or falling water droplets are likely, the sensor should be protected from water reaching or falling directly onto the very hot sensor cap as this can cause massive temperature… https://t.co/o0ByX4dHu7
— SST Sensing Ltd (@SSTSensingLtd) October 29, 2019
#SensorFAQs – Q26 8/12 | …shocks to the cell and heater. Popular methods include a hood over the sensor cap or for the sensor to be mounted in a larger diameter cylinder. https://t.co/o0ByX4dHu7
— SST Sensing Ltd (@SSTSensingLtd) October 29, 2019
#SensorFAQs – Q26 9/12 | At a very minimum the sensor cap should be angled downwards in the application as this will deflect any falling moisture and prevent the sensor cap from filling with water. https://t.co/o0ByX4dHu7
— SST Sensing Ltd (@SSTSensingLtd) October 29, 2019
#SensorFAQs – Q26 10/12 | Using the Sensor with Silicone
Zirconia oxygen sensors are damaged by the presence of silicone in the measurement gas. Vapours (organic silicone compounds) of RTV rubbers and sealants are the main culprits and are widely used in many applications… https://t.co/o0ByX4dHu7
— SST Sensing Ltd (@SSTSensingLtd) October 29, 2019
#SensorFAQs – Q26 11/12 | These materials are often made with cheaper silicones, that when heated still outgas silicone vapours into the surrounding atmosphere. When these vapours reach the sensor, the organic part of the sensor will be burned at hot sensor parts… https://t.co/o0ByX4dHu7
— SST Sensing Ltd (@SSTSensingLtd) October 29, 2019
#SensorFAQs – Q26 12/12 | leaving behind a very fine divided Silicon Dioxide (SiO₂). This SiO₂ completely blocks the pores and active parts of the electrodes. If RTV rubbers are used we advise using high quality, well-cured materials. https://t.co/o0ByX4dHu7
— SST Sensing Ltd (@SSTSensingLtd) October 29, 2019
