Gas sensing



n the United States, around 65 per cent of gas utility first responders carry a SENSIT instrument for gas leak investigation work.

So, with such a dominant position in the market, SENSIT Technologies is under constant pressure to keep ahead of the competition. For over 40 years, SENSIT Technologies

product without the requirement of adding chemical preservatives or stabilisers. The ageing process is slowed down which reduces colour loss, odour and off-taste resulting from product deterioration, spoilage and rancidity that can be caused by mould and anaerobic organisms.

GAS SENSING FOR FOOD STORAGE As a result of extensive stockpiling, a need may arise to increase the storage of foods in preparation for future shortages. Gas sensing plays a vital role within the preservation of both fresh and dry food commodities. For example, carbon dioxide monitoring is essential for the conservation of stored grains and cereals by farmers. Gas sensors can detect mould and insect infestation three to five weeks earlier than temperature monitoring, which means that once the spoilage is detected the problem can be addressed by aerating, turning, or selling the grain. Find out more about the process. Moreover, the process of controlled atmosphere storage uses gas sensing to store dry commodities and fresh fruit and vegetables in controlled atmospheres, which can extend shelf life by up to three times by inhibiting chemical reactions that lead to degradation and spoilage. The low temperatures involved in freezing food kill and prevent the growth of bacteria and help to reduce nutrient loss. Drying foods can also achieve bacterial growth inhibition by removing moisture from the food which in turn slows down the enzyme activity. For frozen and dried food storage, real-time gas monitoring and logging helps prevent unnecessary wastage while keeping produce in its optimal conditions.

Edinburgh Sensors Instrumentation Monthly June 2020

has developed and manufactured hazardous gas detection equipment for applications such as gas leak surveys, underground gas location, pipeline purging, personal safety and confined spaces. The company was founded by the parents of the current CEO Scott Kleppe, and has built a global reputation for its combustible gas leak detectors. “To maintain and build on our market position, we have to continually innovate; by finding new ways to meet the needs of our customers,” Kleppe explains. “However, as we seek to expand our product range and market activity, it is important for us to retain and build on the strengths that made us the market leader.” The core technology in many of the SENSIT

products is an advanced low power semiconductor sensor to measure combustible gases in the LEL (Lower Explosive Limit) range, and a thermal conductivity style sensor to measure combustible gases in the percent volume range.

A BROADER SPECTRUM OF MEASUREMENT PARAMETERS The expansion of the SENSIT product range has been driven by the requirements of new applications and by customers wishing to monitor other gases in addition to Natural Gas, Propane and Butane. Oxygen, for example is a useful parameter to monitor, particularly in confined spaces, where a lack of oxygen can prove fatal. Carbon Monoxide (CO) is also an

important gas; produced when fuel is burned in low levels of oxygen. After CO is breathed in, it enters the bloodstream and mixes with haemoglobin to form carboxyhaemoglobin. This reduces the ability of blood to carry oxygen, which causes the body’s cells and tissue to fail. Consequently, there is a requirement to measure CO levels in many applications, and around 20 years ago SENSIT manufactured its own sensor for this purpose. “At that time, a number of different sensor manufacturers were knocking at our door, seeking to become the supplier of our CO sensors,” explains Kleppe. “Our CO sensor requirement was significantly smaller than the numbers being manufactured by the main manufacturers, so it made sense to exploit their experience and economies of scale.”

Among the prospective suppliers was a

representative from Alphasense in the UK, and following extensive trials the incorporation of Alphasense electrochemical sensors into several of the SENSIT products was agreed.

HELPING CRITICAL WORKERS As a provider of equipment to critical workers, SENSIT had to ensure normal manufacturing output at its facilities near Chicago during the COVID-19 pandemic. “The factory had to be quickly adapted to accommodate social distancing,” Scott explains, “we also moved the factory to a shift pattern, with the facility being completely sanitised between shifts. Staff now work longer shifts, but with a week on, followed by a week off. “Some staff have been able to work from

home, which meant less time lost travelling, with benefits to the work/home balance and the environment, so it will be interesting to see if we can retain those advantages once the ‘new normal’ emerges.”

LOOKING FORWARD Scott believes that the recent pandemic will inevitably make citizens more conscious of risks such as airborne hazards, and this will further drive the market for safety products; particularly personal monitors. At the same time, SENSIT’s partnership with Alphasense will help to meet other market needs such as a broader range of parameters and lower cost sensors with less interference and a longer interval between maintenance. Instruments are also likely to become smaller and even easier to use, with wireless communications and improved functions for transparency and traceability.


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