Certain gas detection applications are better served if the sample is diluted before it reaches the analyzer. Sample dilution is used to…
1. Make measurements beyond the nominal range of the analyzer
2. Extend sensor life by reducing the concentration of gas directed to the sensor—especially in situations where a high background concentration is always present
The Dilution System operates by mixing the sample to be analyzed (the analyte) with diluent purified air or nitrogen. The optimal flow rates for both the analyte and diluent are determined based on the particular application, and are monitored and controlled at integral rotameters.
The diluent is generally introduced from a pressurized source, but may also be obtained from suitably purified ambient air. The analyte is drawn into the dilution system by an integral diaphragm pump, and mixes with the diluent in a tee manifold. The diluted gas sample is then directed to the analyzer, with the excess being exhausted to atmosphere.
Calibration data is provided for both rotameters, as is the initial factory-set dilution ratio for the unit.
In some applications, it may be advisable to use mass flow controllers, instead of rotameters–per customer preference.