Gas Detection
Best Gas Detection System
Gas detection systems are designed to detect hazardous gas levels. These systems can be installed in commercial and residential buildings as well as public spaces such as schools, hospitals, and nursing homes. Gas detectors come in different types and configurations, depending on their usage. This blog post will cover the types of gas sensors and detection systems, how they work, and how gas is detected. Read on!
How is Gas Detected?
- Chemical composition detection: Chemical-based gas sensors utilize a chemical reaction to measure the amount of gas present in the air and give it a voltage reading. The voltage can be measured by an analog or digital voltmeter. This measurement is crucial because as the quantity of the vapor changes, so does the resistance between two electrodes placed in the gas, which is proportional to the voltage.
- Temperature changes: Temperature-based gas sensors work on the principle of heat conduction. As heat rises, so do gases. The gas is collected in a particular aperture, and temperature changes are measured by its resistance to electrical current.
- Electronic emissions: Gases can be detected through electronic emissions because gases interact with the electromagnetic spectrum. This means that they absorb or emit energy at distinct wavelengths in digital signals. As the concentration changes, the absorption also changes accordingly. This makes it possible for gas detectors to measure its quantity using analog circuits and digital signals.
- Radiation detection: Gas sensors based on radiation work on the principle that different gases emit specific wavelengths (or frequencies) of light when stimulated by an external source, such as a lamp. Varying amounts of electricity are passed through the sensing chamber, which excites atoms within it, causing them to emit photons at varying wavelengths.
A lens focuses these exiting photons onto a sensor that converts them into an electrical signal proportional to the wavelength emitted by the gas in question. The electrical signal can be used to indicate the presence of gas.
What are the Two Types of Gas Detection Systems?
1. Over-exposure detection systems
Over-exposure gas detection systems are designed to detect gas at hazardous levels, typically leading to death or severe injuries if left unattended. These systems are used in industrial sites, public places, and locations where gas may be present at dangerous levels.
2. Under-exposure detection systems
Under-exposure gas leak detection systems measure the presence of gases at low levels that aren't immediately hazardous. They are typically used in residential homes, commercial buildings, and locations where the presence of gas may not be dangerous but require monitoring.
What are the Different Types of Gas Sensors?
Metal-Oxide-Semiconductor (MOS) Sensors
These are gas leak detector sensors made from silicon and a semiconducting material. They work by oxidizing the gas at the surface of a specially-prepared metal-oxide wafer, which completes a circuit. Changing the concentration of gas only changes the resistance between electrodes, which is then easily measured.
Chemical Sensors
Chemical sensors work by coating a surface with a chemical that reacts with specific gases in the air. These sensors can detect a broader range of gases, and they are less susceptible to false readings. However, they take more time to detect gas levels.
Ionization-Sensitive Field Effect Transistor (ISFET)
ISFET is a natural gas detector containing a diode that's sensitive to changes in electric potential when differentiating different gases. These gases include hydrogen and carbon monoxide, which are fatal.
Photoionization Detectors
These systems can detect a wide range of gases, including methane and hydrogen. The sensors contain two electrodes that generate an electric field in the air surrounding them. This, in turn, generates a positive and negative ion. When exposed to light, the positive and negative ions can't neutralize each other. As such, they're attracted to a negatively charged grid.
How Does a Gas Monitors Work?
A gas detector works by measuring the volume of one or more gases in a given air volume. Depending on the sensor used, they determine the gas concentration of any flammable or toxic gases in the air and issue alerts when they reach dangerous levels.
Calibration gas detectors also work by measuring the amount of energy in beams emitted when a gas is introduced into the detector. A small portion of that beam is then monitored with a sensor, and if there is any change in its intensity over time, it means there is some level of gas present in the air sample.
Get Quality Gas Detection Systems to Protect Yourself and Your Employees from Any Combustible Gases
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