The sensor carbon dioxide sensor or CO 2 is an instrument for measuring carbon dioxide gas. The most common principles for CO 2 sensors are infrared gas sensors (NDIR) and chemical gas sensors. Measuring carbon dioxide is important in indoor air quality monitoring, lung function in the form of capnograph devices, and many industrial processes.
Video Carbon dioxide sensor
Nondispersive Infrared (NDIR) CO 2 Sensor
The NDIR sensor is a spectroscopic sensor for detecting CO 2 in a gas environment with its characteristic absorption. Its main components are infrared sources, light tubes, interference filters (wavelengths), and infrared detectors. The gas is pumped or diffuses into the light tube, and the electronics measure the absorption of the wavelength of the light characteristics. NDIR sensors are most commonly used to measure carbon dioxide. The best of these have a sensitivity of 20-50 PPM. Typical NDIR sensors are valuable in the $ 100 to $ 1000 (US) range.
New developments include using microelectromechanical systems to lower the cost of these sensors and to make smaller devices (eg for use in AC applications). The NDIR sensor CO 2 is also used to dissolve CO 2 for applications such as beverage carbonation, pharmaceutical fermentation and CO 2 absorption applications. In this case they are mated to ATR (attenuated total reflection) optic and measure in situ gas.
Another method (Henry's Law) can also be used to measure the amount of dissolved CO 2 in a liquid, if the amount of foreign gas is not significant.
Maps Carbon dioxide sensor
Chemical Sensors CO 2
Chemical CO 2 sensors with sensitive coatings based on polymers or heteropolysiloxane have a major advantage of very low energy consumption, and can be reduced in size to suit microelectronic based systems. On the downside, short-term and long-term effects and a rather low overall age are the main obstacles when compared to the NDIR measurement principle. Most CO? the sensor is fully calibrated before shipping from the factory. Over time, the zero point of the sensor needs to be calibrated to maintain long-term sensor stability.
Apps
- Example:
- Modified atmosphere
- Indoor air quality
- Stowaway detection
- Cellar and gas stores
- Ships
- Greenhouse
- Landfill gas
- Limited space
- Cryogenics
- Vent management
- Mining
- Rebreathers (SCUBA)
- For indoor human occupation count
- For HVAC applications, CO 2 sensors can be used to monitor air quality and special needs for fresh air. Measuring CO 2 level indirectly determines how many people are in the room, and ventilation can be adjusted. See controlled ventilation request (DCV).
- In applications where direct temperature measurements do not apply, NDIR sensors can be used. The sensor absorbs infrared radiation (IR) which is released by the hot surface.
See also
- Flue gas analyzer
- Oxygen sensor
References
Source of the article : Wikipedia
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