The truck is moved as close to the sample point as is

practical. A flexible sample line is then uncoiled and attached

to the probe in the flowing natural gas pipeline. If the dew

point of the gas or the weather demands it, this flexible

tubing must be heated. A sample of the gas is extracted from

the probe in the line, purged through the flexible line and then

transported to the analyzer. There it is processed for particle

removal and phase integrity, injected onto the

chromatographic columns where component separation

occurs. These components are then quantified by peak

integration and concentration is calculated. The other data of

interest is then calculated from these concentrations.

The averaged output can be formatted to be accepted by a

3rd party gas accounting software system, allowing

automatic downloads of the analysis data. Analysis done on

site is valuable because:

• Transportation of DOT regulated gas cylinders is avoided

• Time and cost of subsequent laboratory analysis

• Problems with sample handling

• Economic solution for gas quality measurement when the

gas volumes are too low to justify on-line chromatography