Sample conditioning

The term “sample conditioning” simply means the preparation of the gas sample containing your analyte to render it suitable for introduction into your gas analyzer. This is usually less of a consideration in ambient air monitoring applications than in source monitoring applications.

When sampling from a source such as an industrial process, utility stack, or tailpipe, the sample will likely contain water and particulate matter, and could be at an elevated temperature. Even in the rare case in which these factors might not damage the analyzer, they could likely foul the sample lines involved. As such, classic sample conditioning would involve bringing it to a suitable temperature, removing particulate matter, and lowering the dew point to be below the temperature of your analyzer.

However, all this must be done in a manner to minimize the loss of analyte.

As you might expect, there are many methods available to accomplish this. Particulate filters can be in-line, or directly inserted into the source, via a sample probe. In-line filters must be periodically changed, and in-source filters—depending on the nature of the process being monitored—can be subject to an automatic backflush or blowback cycle.

The dew point can be lowered with coalescer filters; chiller or desiccant devices ; or membrane drying.

Some ambient air applications also require sample conditioning—usually limited to filtration. Such filters are usually mounted to the inlet of the analyzer. In applications in which sample is to be drawn from some distance to the analyzer, end-of-line filters are usually employed.

If you require further information on sample conditioning for your gas detection application, please contact us.

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