Monitoring & metering
COUNTING THE COST OF UNRELIABLE GAS ANALYSERS
B
ack in 1977 when Signal Group first started manufacturing gas analysers, components were less proficient and consistent, and analysers required a higher level of ‘tender loving care’. At that time, James Clements, the company’s managing director, was little more than a twinkle in his father’s eye, but today, with an engineering degree and over 23 years of experience in gas analyser design, Clements has dedicated his career, and his company, to the development of reliable gas analysers.
By focusing the company’s product line on trust and reliability, Clements has found that Signal is frequently contacted by organisations that are suffering from the poor performance of competitors’ analysers. “I wish I could write a book about the problems that we have been invited to solve,” Clements says. “But unfortunately, companies rarely wish to air their dirty linen in public, so we can only talk about these instances in quite general terms.” In many cases, manufacturing or processing facilities are simply unable to operate when a gas analyser malfunctions. This might be because the analyser performs a regulatory compliance function, or that it provides essential measurements for process control. Either way, the cost of a shutdown can be enormous – not just from lost production, but also from unhappy customers, wasted product, and from the cost of re-starting a process once the analyser situation has been resolved.
SOURCES OF ERROR
Sampling errors are a common cause of problems. Samples need to be representative and they need to remain that way as they pass to the analysers and enter the measurement cell. Invariably samples must be free from particulates, and filters must be free from blockages. Equally, sample lines should not allow condensation, because moisture could damage the analyser, and target gas species may dissolve in the water and thereby avoid being measured. Incorrect calibration is also a major cause of inaccurate readings, either because the calibration interval is too long, or because incorrect procedures have been followed, or faulty calibration equipment is employed. The performance of badly designed sensors/ analysers can decline with age, leading to inaccuracy or complete failure. Similarly, measurement accuracy can drift as a result of wear or contamination. For example, dust, dirt, oil, soot, and water/moisture can block the gas path to the analyser, or soil the optical components of some analyzers. Also, exposure to certain chemicals can permanently damage or reduce a gas analyser’s sensitivity, and some gas analysers respond to non-target gases (cross- sensitivity), leading to false readings or inaccurate measurements for the intended gas.
Temperature and humidity extremes can impact analyser performance, and some analysers are
more susceptible to physical trauma because components fail or the integrity of the sampling system is compromised.
Strong electromagnetic fields from nearby equipment can interfere with a device’s electronics if the instrument is not adequately protected, and power issues can cause a device to fail, shut down unexpectedly, or display error messages. Hopefully, it is not necessary to point out that incorrect operation or installation can also cause faults or inaccurate readings.
CUSTOMERS DRIVE PRODUCT DEVELOPMENT
It is no coincidence that Signal Group manufactures a range of sample handling and calibration equipment. These well-proven devices were initially developed to resolve customers’ issues and have become an important component of Signal’s key brand value of measurement reliability. Importantly, Clements believes that Signal invests a higher proportion of its costs in product development than any other major gas analyser manufacturer, and for good reason. “With the voice of the customer driving everything we do, we are constantly looking for ways to enhance the accuracy, reliability and usability of our analysers,” Clements says. “With almost 50 years of experience, helping to fix poor sampling systems
42 April 2026 Instrumentation Monthly
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