Precision Measurement: Oxygen, CO, and Concentration Analyzers

Oxygen Measurement Systems

Oxygen measurement systems, including electrochemical and zirconium oxide types, are crucial for determining the percentage of oxygen present in a gas concentration.

Electrochemical Oxygen Cell Operation

An electrochemical cell generates an electric potential, similar to a battery. The value of this potential is directly proportional to the oxygen concentration in the gas mixture.

Zirconia Cell Operation

The zirconia cell also generates an electric potential based on the oxygen level in the mixture, providing an accurate measurement of the oxygen percentage.

CO Analyzers for Combustion & Environmental Control

CO analyzers are essential for monitoring and controlling combustion processes and environmental emissions. Two primary types of CO measurement systems are utilized: electrochemical and infrared cells.

Electrochemical CO Cell

This cell features three electrodes (sensor, reference, and counter electrode) separated by a thin layer of electrolyte. This setup creates a gaseous diffusion barrier that limits the flow of gas to the sensor electrode, thereby ensuring the electrochemical activity of the sensor.

Infrared CO Cell

The infrared cell employs an analytical technique based on absorbing infrared radiation. It is an instrument that allows for the continuous determination of the concentration of one or more components within a gas mixture.

Infrared Theory

Infrared radiation occupies a region of the electromagnetic spectrum between wavelengths of approximately 0.8 to 100 microns.

Components of an Infrared CO Cell

• Infrared Source: Responsible for emitting radiation in the specific spectral range required for analysis.
• Sample Chamber: Positions the sample gas between the energy source and the detector. A larger chamber generally leads to higher sensitivity.
• Filters: Devices that allow only a specific part of the incident radiation to pass through them.
• Detectors: Convert the incident infrared radiation into an electrical signal.
• Modulator: Responsible for generating a pulsed signal at the detector.

Concentration Analyzers: Light Reflection & Refraction

Concentration analyzers are used to measure the concentration of a solution by utilizing the principles of light reflection and refraction.

Refraction of Light

Refraction is the phenomenon by which light changes its speed and direction as it passes from one medium to another of different optical density.

Reflection of Light

Reflection is the phenomenon where light returns from a surface, retaining its total value or intensity.

Refractive Index

The refractive index is defined as the ratio between the speed of light in a vacuum and the speed of light in a specific medium.

Critical Angle

The critical angle refers to a specific angle of incidence beyond which total internal reflection occurs, meaning the light beam is entirely reflected rather than refracted.