Sensors focus on anaesthesia, refrigerants and food

Pyreos, a manufacturer of miniature, rugged, pyroelectric, mid-infrared sensors and detectors which respond faster and minimise power consumption, has expanded its sensor portfolio by 30% in response to growing demand from customers in a wide range of market sectors.

The TO39-packaged pyroelectric infrared detectors offer high signal-to-noise ratio (SNR), fast response, high frequency operation, and high temperature stability, making them ideal components for measurement systems in applications including anaesthesia, refrigeration and food processing.

All Pyreos products use its unique thin-film PZT pyroelectric technology, whose low thermal mass increases the sensors’ speed of response, enabling high measurement rates, high SNR and lower-power systems. They also have low microphonics and class-leading thermal and electrical stability.



Operating in current mode, the dual and quad sensors offer a responsivity of ~200,000 V/W, and have a fast, stable response over a wide operating frequency range and a long operating lifetime.

The sensing elements form part of a low-noise internal circuit that includes a CMOS op-amp and a 10 GΩ feedback resistor which produces voltage output signal.

In the dual channel device, the output voltage is centred on half the supply voltage, allowing single power supply operation and reducing the need for external gain stages that could introduce noise.

Designed for use in gas-detection, safety-monitoring and measurement systems in anaesthesia equipment, refrigeration safety and maintenance monitoring, food-safety and process control systems, the components are also used in quality management, process control and safety monitoring for markets including oil and fuel processing, chemicals and pharmaceuticals.

The parts have also been developed in response to legislative pressure in many markets, such as rising demands to test the quality and origin of food; phasing out of more damaging refrigerants, and the World Health Organisation’s drive for more universal use of capnography during anaesthesia.

“Optical mid-infrared measurement of gases and fluids is growing worldwide and bringing fast, accurate measurement to new applications. By deepening our range in refrigeration, anaesthesia and food, we are enabling more users to develop off-the-shelf products for these key markets,” said Andrew Wallace, CEO at Pyreos. “The combination of the widely-used TO-39 packaging option, internal signal-conditioning circuitry, and a wide range of filter options will make it easy for designers to add fast, stable and robust gas-detection facilities to their designs.”

Packaged in the TO-39 can, with a filtered window over each of the two or four sensing elements, the dual-sensor parts are available in over 20 variants, using different combinations of filters to tune them to detect gases including methane, carbon monoxide, various forms of carbon dioxide, anaesthesia gases, nitrous oxide, freon, ethylene, and more.

There are also variants tuned to detect specific aspects of food processing, such as the presence of sugars (eg, lactose), ethanol, protein and fat.

The quad-sensor parts use the additional two sensors and filters to increase the specificity of their detection. Variants are available for exhaust gases, and anaesthesia.

The dual sensors work at operating voltages between 2.7V and 8V, while the quad sensors need a supply of between 2.7V and 5V. The operating temperature range for both types is –40 to +85°C.