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Gas sensors are versatile devices that are essential for not just ensuring workplace safety but can help improve production efficiency and reduce product loss, resulting in industrial cost-savings. Sensitive, rapid detection of commonly used gases such as methane and carbon dioxide is of vital importance in a range of industries, including petrochemistry, waste management, gas extraction and refinement, mining, and many others.
MIPEX has developed the world’s lowest power non-dispersive infrared (NDIR) gas sensor for highly sensitive, reliable detection of gases such as methane and carbon dioxide. By making use of IR LED sources and new sensor technologies, MIPEX has been able to create robust, non-serviceable gas sensors that can easily be used by OEMs for easy incorporation into gas detector devices that simply need a battery as a power source.
Miniature sensors with LEDs
The MIPEX-02 gas sensors are ideal for use in dangerous environments as they are fully digital, micro-chip based sensors with microcontrollers that can carry out self-diagnostics for higher fault tolerances, ensuring full linearity of detection of a range of gas concentrations. Again, these also benefit from low-power draw of < 3 mW and being small, industry-sized sensors that have advanced digital interfaces.The appeal of using LED NDIR sources is that LEDs are incredibly energy efficient and so the resulting gas sensor has a very low energy draw. In the case of the MIPEX sensor range, where there are custom sensors available depending on the exact application needs.
NDIR technologies are very popular in gas sensors as many common gases, absorb light very strongly in the infrared region of the electromagnetic spectrum. This means that using a coupled IR source and detector, it is possible to measure even low concentrations of these gases with real-time online monitoring.
MIPEX optical gas sensor technology.
One of the key advantages of this combination of sensitivity and power draw is for using these MIPEX sensors, in particular the MIPEX-04, like gas sensors in wireless devices. The miniature scale of the MIPEX sensors means that they can easily be incorporated into wireless safety monitoring devices. Particularly for safety applications, it is often advantageous to have portable detectors that require no installation time and can be immediately deployed.
Wireless Gas Safety
The possibility of incorporating gas sensors into wireless devices was previously very challenging to realize. Catalytic bead technologies were at the heart of most gas sensors, where the gas molecules to be detected are adsorbed to a catalytic substrate, leading to a change in resistance that can be converted into electrical signals. As each detection event also led to the degradation of the catalyst, these types of sensors had finite lifetimes. Since the pellistors of the catalytic bead sensor are heated to about 450 °C such a sensor also requires a sizeable power draw.
Instead, the MIPEX range sensors are designed to be not just fail-safe, but energy efficient. The new MIPEX-04 Combustible Gas Sensor offers an unprecedentedly low level of power consumption not found in any other combustible gas sensor on the market. It’s up to 1000+ times more energy-efficient than a typical combustible gas sensor. This makes them ideal for incorporation in Wireless Sensor Networks or the ‘Internet of Things’, connected gas monitors that are linked to a data distribution network that can, in conjunction, be used to continually monitor large areas.
One possible use of such a sensor network could be for monitoring gas concentrations throughout an industrial plant. In the event of a gas leak of a gas such as methane, the MIPEX-04 sensor is designed as well with inbuilt intrinsic safety “ia” meaning that, even if the maximum permitted values are applied to the device terminals, it will not cause ignition and pose additional safety risks. This is an essential feature of sensors in such safety systems and means that the MIPEX-04 can be used in the harshest environments or even in situations where significant gas leaks may be expected. Strategic use of multiple MIPEX-04 sensors throughout the building makes it possible to create a sensor network that can be used to trace the gases route throughout the building. This information can then be passed to hazard or rescue teams for a more efficient, safer response.
While reducing the power consumption of gas sensors is obviously beneficial from energy consumption and environmental point of view, MIPEX gas sensors have additional environmental benefits. Two of the main gases they are designed to detect, methane and carbon dioxide, are known greenhouse gases. While many gas sensors allow for continual online monitoring of these gas concentrations, the advantage of MIPEX sensors is that they are highly sensitive and based on LED technologies so even in the event of a small gas leak, they are capable of detecting such concentrations. The low power draw and properties can be incorporated into more complex either safety or control networks, in the event of a gas leak, the sensors can quickly detect a problem and be used as part of a feedback loop to halt production and further gas loss.
Such leak detection may be used as part of LPG bottling processes or for the detection of leaks from remote natural gas pipelines. The miniature nature of the MIPEX sensors (the MIPEX-02 and MIPEX-03 have the industry-standard size - 20 mm diameter x 16 mm height excluding pins) in combination with the low power consumption means that there is the potential to incorporate them into unmanned aerial vehicles for remote surveying of such pipelines. The MIPEX-02 and MIPEX-03 also have digital interfaces and can be used without any system or service needed.
The robust nature of the LED technology also helps to increase sensor lifetime and the MIPEX-04 is easily able to cope with working in a variety of environmental conditions. It is possible to install dust filters and the output readings are linearized with a temperature compensated output over a large range (-40 to 60◦C). However, filters or an enclosure are not necessary with MIPEX sensors due to their intrinsic safety but can be useful for use in harsh environments.
Being able to use sensors without filters means sensors can be mounted on walls in any location and filters are easily replaced if they are contaminated, without needing to remove the sensor. The response time of the device alone is just 12 seconds and as it is manufactured to the highest technical standards with quality management system approved by ISO 9001:2015 certificate, so the customer can be assured of long device lifetimes with excellent reliability.
References and Further Reading
- MIPEX, https://mipex-tech.com/about (accessed April 2019)
- P. Werle, F. Slemr, K. Maurer, R. Kormann, R. Mücke and B. Jänker, Opt. Lasers Eng., 2002, 37, 101–114.
- MIPEX-02, https://mipex-tech.com/catalog/mipex-02, (accessed April 2019)
- MIPEX-03, https://mipex-tech.com/catalog/mipex-03, (accessed April 2019)
- MIPEX-04. https://mipex-tech.com/catalog/mipex-04, (accessed April 2019)
- A. Baranov, D. Spirjakin, S. Akbari and A. Somov, Sensors Actuators, A Phys., 2015, 233, 279–289.
- Gas Detection for LPG, http://www.hse.gov.uk/pubns/gasdetector.pdf, (accessed April 2019)
- Natural Gas Leak Detection, https://www.netl.doe.gov/sites/default/files/2018-05/scanner_technology_0104.pdf, (accessed April 2019)
This information has been sourced, reviewed and adapted from materials provided by MIPEX.
For more information on this source, please visit MIPEX.