An extractive analyzer, also known as an extractive gas analyzer, is a type of gas analyzer used to measure the concentration of gases or vapors in a process or ambient air. The term “extractive” refers to the sampling method employed by the analyzer, which involves extracting a sample of the gas or vapor from the process or environment and then analyzing it in a separate location.

Here’s how an extractive gas analyzer generally works:

1. Sample Extraction: The analyzer uses a sampling probe or sampling system to extract a representative sample of the gas from the process or ambient air.

2. Sample Conditioning: The extracted gas sample may contain moisture, particulates, or other impurities that can interfere with the analysis. Therefore, the sample is typically conditioned to remove these impurities and prepare it for accurate measurement.

3. Analysis: The conditioned gas sample is then passed through the analyzer’s detection system, which can be based on various principles such as infrared absorption, ultraviolet (UV) absorption, or gas chromatography, depending on the gas being measured.

4. Concentration Measurement: The analyzer measures the concentration of the target gas in the sample using the chosen detection principle.

5. Data Display and Logging: The analyzer displays the measured concentration of the gas on a display panel and may also log the data for further analysis or recording.

Extractive gas analyzers are commonly used in industrial processes, environmental monitoring, and research applications where accurate and reliable gas concentration measurements are required. They are particularly useful for measuring gases that are present in low concentrations or when continuous in-situ monitoring is not practical.