The sample point fixing may act as a heat sink and your gas sample temperature will fall, producing condensation. Ambient air temperatures can also promote condensation. Quite often, therefore, heated sample lines are needed to take the gas to a sample conditioning device, which will stabilize the sample for you. The factors affecting the monitor are usually physical gas characteristics such as temperature and particle loading. Sample conditioning often provides the opportunity to eliminate condensation problems.
Many particle filters are available to provide a clean gas sample.
The temperature of the gas sample can be reduced by dilution. This has the effect of lowering the possibility of condensation of vapours from the gas sample, including water, and quenching any reaction taking place in the sample. A dilution system pulls in a gas sample from the vent into a flow of clean, cold air or nitrogen. It is the flow of air that usually acts as the extraction driver. A constant mix ratio of sampled gas to dilution gas allows calculation of the actual concentration in the vent of the gas after analysis by the monitor.