Infrared point sensor
Encyclopedia
A infrared point sensor is a point gas detector
based on the nondispersive infrared sensor technology.
, light source intensity and component efficiency. The transmitted beams from two infrared
sources are superimposed onto an internal beam splitter
. 50% of the overlapping sample and reference signal is passed through the gas measuring path and reflected back onto the measuring detector. The presence of combustible gas
will reduce the intensity of the sample beam and not the reference beam
, with the difference between these two signals being proportional to the concentration of gas present in the measuring path. The other 50% of the overlapped signal passes through the beam splitter and onto the compensation detector. The compensation detector monitors the intensity of the two infrared sources and automatically compensates for any long term drift.
Mean time between failures may go up to 15 years.
can be used to raise the temperature from optical surfaces above ambient to enhance performance and to prevent condensation on the optical surfaces.
) range. Flammable gases are measured in the 0 - 100 % lower flammable limit
(LFL) or lower explosive limit (LEL) range.
Gas detector
A gas detector is a device which detects the presence of various gases within an area, usually as part of a safety system. This type of equipment is used to detect a gas leak and interface with a control system so a process can be automatically shut down...
based on the nondispersive infrared sensor technology.
Principle
Dual source and dual receivers are used for self compensation of changes in alignmentAlignment
Alignment may refer to:* Alignment , secondary evidence used to associate features such as postholes* Alignment , in Israel from 1965 to 1992...
, light source intensity and component efficiency. The transmitted beams from two infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
sources are superimposed onto an internal beam splitter
Beam splitter
A beam splitter is an optical device that splits a beam of light in two. It is the crucial part of most interferometers.In its most common form, a rectangle, it is made from two triangular glass prisms which are glued together at their base using Canada balsam...
. 50% of the overlapping sample and reference signal is passed through the gas measuring path and reflected back onto the measuring detector. The presence of combustible gas
Gas
Gas is one of the three classical states of matter . Near absolute zero, a substance exists as a solid. As heat is added to this substance it melts into a liquid at its melting point , boils into a gas at its boiling point, and if heated high enough would enter a plasma state in which the electrons...
will reduce the intensity of the sample beam and not the reference beam
Reference beam
A reference beam is a laser beam used to read and write holograms. It is one of two laser beams used to create a hologram. In order to read a hologram out, some aspects of the reference beam must be reproduced exactly as when it was used to write the hologram...
, with the difference between these two signals being proportional to the concentration of gas present in the measuring path. The other 50% of the overlapped signal passes through the beam splitter and onto the compensation detector. The compensation detector monitors the intensity of the two infrared sources and automatically compensates for any long term drift.
Mean time between failures may go up to 15 years.
Micro heaters
Micro heatersHeating element
A heating element converts electricity into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element....
can be used to raise the temperature from optical surfaces above ambient to enhance performance and to prevent condensation on the optical surfaces.
Range
Toxic gases are measured in the low parts per million (ppmParts-per notation
In science and engineering, the parts-per notation is a set of pseudo units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they are pure numbers with no associated units of measurement...
) range. Flammable gases are measured in the 0 - 100 % lower flammable limit
Lower flammable limit
Lower flammability limit , usually expressed in volume per cent, is the lower end of the concentration range of a flammable solvent at a given temperature and pressure for which air/vapor mixtures can ignite. The flammability range is delineated by the upper and lower flammability limit. Outside...
(LFL) or lower explosive limit (LEL) range.
See also
- List of sensors
- Maintenance-free operating period
- Service lifeService lifeA product's service life is its expected lifetime, or the acceptable period of use in service. It is the time that any manufactured item can be expected to be 'serviceable' or supported by its manufacturer....
- ATEX directiveATEX directiveThe ATEX directive consists of two EU directives describing what equipment and work environment is allowed in an environment with an explosive atmosphere...
II 1G EEx ia IIC T6 - Atex certified Reed Sensor
- Infrared gas analyzerInfrared gas analyzer]An infrared gas analyzer measures trace gases by determining the absorption of an emitted infrared light source through a certain air sample. Trace gases found in the Earth's atmosphere get excited under specific wavelengths found in the infrared range. The concept behind the technology can be...
- for gas monitoring and analysis, rather than leak detection.