What Is a Gas Analyzer?
A gas analyzer is a device to measure the concentration of gases.
It can measure single or multiple gases. Gas concentration can measure carbon dioxide, nitrogen oxides, toxic gases, flammable gases, and other gases.
Therefore, the principles used in the instruments vary. The main purposes of measuring gas concentrations include management and control of production processes, environmental monitoring, and ensuring worker safety in factories and work sites.
Applications of Gas Concentration
Gas concentration is used to measure gas concentrations, as described above. Gases vary in nature, from gases found in the atmosphere, such as carbon dioxide and oxygen, to propane gas used as fuel.
Some of these gases are harmful to the human body if present in a space above a certain concentration, while others have increased in concentration in the atmosphere due to human activity. Gas concentration is used to detect such harmful gases and for environmental monitoring.
1. Industrial Field
Gas concentration is used in industrial environments to ensure worker safety. For example, in chemical and manufacturing plants, they can be used to monitor the concentration of harmful gases and vapors and to alert workers when abnormal concentrations are detected, thereby preventing hazards at the work site. Gas concentration is also used in the mining and extraction industries to detect toxic and explosive gases.
2. Environmental Field
Gas concentration also plays an important role in environmental protection activities. By monitoring the concentration of gases in the air, they are used to determine the state of air pollution and to inspect and measure exhaust gases. Examples include analyzing the constituents of automobile exhaust and monitoring air pollutants from factories.
3. Medical Field
Gas concentration is also used in medical equipment and medical environments. They play an important role in ensuring patient safety by monitoring oxygen levels during anesthesia and measuring carbon dioxide levels in respiratory equipment.
Blood gas concentration will also measure oxygen and carbon dioxide concentrations in arterial blood for clinical diagnosis and treatment.
Principles of Gas Concentration
The actual analysis is based on the application of the gas’s characteristics, such as refractive index, paramagnetism, solution conductivity, and thermal conductivity. In addition, gas concentration is mainly based on two main principles: the “chemical principle” and the “physical principle”.
1. Chemical Principle
One approach to a gas analyzer is to use the chemical reaction of gases to measure their concentration. In this approach, a sensor is used that is based on its reaction to a specific gas.
When the gas comes into contact with the sensor, a chemical reaction occurs, resulting in an electrical change. The sensor detects this change and based on it, the concentration of the gas is measured. Sensors based on this chemical principle are widely used in oxygen meters and carbon dioxide meters.
2. Physical Principle
Another approach to gas concentration is to use physical principles based on the interaction with the gas. In this approach, sensors based on the properties and behavior of the gas are used.
For example, the concentration of a gas can be estimated by measuring light absorption, scattering, conductivity, and temperature changes. Sensors based on this physical principle are used in Infrared gas concentration and Electric Conduction Gas Analyzers.
Types of Gas Concentration
There are several types of gas concentration for use in a variety of applications:
1. Electrochemical Formula
Electrochemical equation uses the electricity-related properties of a substance and its electrochemical characteristics. There are several types, such as those that apply electrical conductivity when a gas dissolves in a solution and ion electrode type that uses electrodes.
2. Optical Type
Optical type uses light such as ultraviolet, visible light, and infrared light to make measurements. It consists of a light source and a receiver that catches the irradiated light.
3. Electromagnetism
This method uses electromagnetic properties. It applies the magnetic force generated when a magnetic field is applied to a gas. It is often used to measure oxygen because oxygen is the only gas with strong paramagnetic properties compared to other gases.
4. Thermal Method
Gas concentration is measured based on the temperature change that occurs when the gas comes into contact with a heated metal wire and the thermal equilibrium. There are two types: thermal conduction and catalytic combustion. The catalytic combustion type is widely used for household gas alarms because it is inexpensive and can be mass-produced.