IR transmitters with two wavelengths are typically used. One so-called reference wavelength and just one measuring wavelength. Very strict limits are applied to these systems. The absorption spectra of many hydrocarbons are located in the wavelength range of 3.3 µm and overlap to a large extent. This means that gases with overlapping spectra and just one measuring wavelength can no longer be clearly distinguished. Some hydrocarbons, e.g. the frequently used welding gas acetylene, are non-absorbing in the wavelength range of 3.3 µm, but absorb instead in neighbouring wavelength ranges.
In many practical applications, it is not essentially important which gas is responsible for the explosion risk. Therefore, early warnings through the broadband measurement of hydrocarbons in order to monitor the lower explosion limit (LEL) must be guaranteed. False alarms with uncritical concentrations of individual gases or solvents are thus absolutely unacceptable.
IR transmitter for explosion protection with increased safety
Patented IR technology (NDIR)
4-beam, 4-wavelength technology
Temperature, moisture and pressure compensation
Maintenance and service-friendly
Ignition protection class with increased safety "e"