However, high temperatures combined with low humidity causes the electrolyte to dry out, impairing sensor performance so that the sensor has to be replaced regularly meaning high replacement costs, time and efforts. In traditional H 2S sensors, detection is based on electrochemical technology, where electrodes are used to detect changes induced in an electrolyte by the presence of the target gas. Our new High Temperature (HT) H 2S sensor for XgardIQ has been revisited and improved by our team of Crowcon experts by using a combination of two ingenious adaptations to its original design. In this blog, we’re focusing on the requirement for detection of hydrogen sulphide (H 2S)- a long running challenge for the Middle East’s gas detection industry.īy combining a new trick with old technology, we’ve got the answer to reliable gas detection for environments in the harsh Middle Eastern climate. Our new HT H 2S sensor has been proven to be a reliable and resilient solution for the detection of H 2S at high temperatures- a solution that doesn’t fall asleep on the job!Ĭlick here for more information on our new High Temperature (HT) H 2S sensor for XgardIQ.ĭue to extreme heat in the Middle East climbing up to 50☌ in the height of summer, the necessity for reliable gas detection is critical. The new developments of our sensor allow operation of up to 70☌ at 0-95%rh- a significant difference against other manufacturers claiming detection of up to 60☌, especially under the harsh Middle Eastern environments. To tackle the drawbacks of MOS sensors, we’ve revisited and improved on the electrochemical technology with our new High Temperature (HT) H 2S sensor for XgardIQ. Due to H 2S being a “sticky” gas, it is able to be adsorbed onto surfaces including those of sinters, in result slowing down the rate at which gas reaches the detection surface. MOS sensors excel in reacting quickly to H 2S, therefore the need for a sinter counteracts this benefit. This late registering of low-level gas presence can then delay the warning of a serious gas leak, opportunity for evacuation and the extreme risk of lives.
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This means that the control panel may show a zero read-out for some time after levels of H 2S have begun to rise. Often the sensor is used with a level of “zero suppression” at the control panel. The device is also open to the acidic environment created by the local sand in the Middle East, effecting conductivity and accuracy of gas read-out.Īnother significant safety implication of a MOS sensor is that with output at near-zero levels of H 2S can be false alarms. In other industries, semiconductors are often encased in epoxy resin to avoid this, however in a gas sensor this coating would the gas detection mechanism as the gas couldn’t reach the semiconductor. It uses a lot of power which poses an additional issue of dramatic changes of temperature in the DC power cable, causing changes in voltage as the detector head and inaccuracies in gas level reading.Īs its metal oxide semiconductor name suggests, the sensors are based around semiconductors which are recognised to drift with changes in humidity- something that is not ideal for the humid Middle Eastern climate.
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Some users may find this a hinderance for production, as well as extended time for servicing and maintenance. MOS manufacturers therefore recommend users to allow the sensor to equilibrate for 24-48 hours before calibration. However, when initially switched on, the heater takes time to warm up, causing a significant delay between turning on the sensors and it responding to hazardous gas.
![crowcon detection instruments ltd a halma company crowcon detection instruments ltd a halma company](https://www.limkimhai.com.sg/wp-content/uploads/2020/09/Products-and-Service-Guide.png)
MOS sensors require a heater to equalise, enabling them to produce a consistent reading. Of course, this is a huge safety risk for workers in the area… no-one wants to face a gas detector that ultimately doesn’t detect gas.
![crowcon detection instruments ltd a halma company crowcon detection instruments ltd a halma company](https://www.crowcon.com/wp-content/uploads/2020/12/mps_logo.png)
One of the major drawbacks of the technology is the liability of the sensor “going to sleep” when it doesn’t encounter gas for a period of time. This blog covers why this technology can prove difficult to maintain and what issues users can face. However, users and gas detection professionals have realised MOS sensors are not the most reliable detection technology. MOS (metal oxide semiconductor) sensors have been seen as one of the most recent solutions for tackling detection of hydrogen sulphide (H 2S) in fluctuating temperatures from up to 50☌ down to the mid-twenties, as well as humid climates such as the Middle East.