Sensor Technology for industrial safety - Jonathan Gilby

New technologies come and go but the bulk of today’s industrial safety gas detection equipment is based on tried and trusted methods. Although the methods are old, constant innovation is keeping track with users’ demands for ever smaller and more sophisticated instruments. This is as true on the sensor front as it is in the software and instrument design.

Detection of a wide range of simple reactive gases such as Oxygen, Carbon Monoxide and Hydrogen Sulphide is possible using electrochemistry, which captures the electrons exchanged in a chemical reaction and allows them to be measured as an indication of the amount of gas present.

Non reactive gases such as methane can not be detected by this principle, however their combustible properties allow a simple detection system based on a heated bead to be used and this is known as the Pellistor or Catalytic bead.

Both of the above detection systems make use of the chemical reactivity of the gas, however the physical properties may also be used to provide the detection principle. Non Dispersive Infra Red detectors measure the absorption of Electro magnetic radiation by the gas as it excites the vibrational resonances in the molecular structure. The wavelength of radiation used is chosen either to select a particular gas or to allow the detection of a board range of chemically similar gases, such as the aliphatic saturated hydrocarbons.

Turning these detection principles into a sensor suitable for the industrial safety market has been City Technologys forte for the last 25 years, and some of the latest innovations are described here as well as presenting the basic principles for each detection method