8.4 Split flow

Split flow path (blue) superimposed on rear of the At-Line Sampling Module

• If large amounts of analyte from the sample are saturating the Lonestar detector, it may be useful to split off some of the sample flow and vent it away from the detector.
• It may also be helpful to do this if the humidity of the sample flow is too great and this is suppressing the sensitivity of the Lonestar detector to the desired analytes.
• Caution! The split flow should always be vented appropriately. If toxic or harmful compounds are present in the sample, the split flow must be vented into a fume hood.
• The split flow should be taken from the first port in the sample transfer line, before the flow has passed through the particulate filter.
• The flow rate may be controlled by a needle valve, rotameter or mass flow controller. Alternatively, a flow restriction aperture may be inserted into the port (see next section).