Gas Plumbing - Agilent Technologies 6820 Getting Started

Site Preparation

Gas Plumbing

All compressed gas cylinders should be securely fastened to an immovable
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structure or permanent wall. Compressed gases should be stored and handled in
accordance with the relevant safety codes.
Gas cylinders should not be located in the path of heated oven exhaust.
To avoid possible eye injury, wear eye protection when using compressed gas.
Do not use methylene chloride or other halogenated solvents to clean tubing that will
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be used with an electron capture detector. They will cause elevated baselines and
detector noise until they are completely flushed out of the system.
Gases should be supplied to the instrument only through preconditioned copper tubing
(part number 5180-4196). Do not use ordinary copper tubing—it contains oils and
contaminants.
Do not use plastic tubing to supply detector and inlet gases to the GC. It is permeable
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to oxygen and other contaminants that can damage columns and detectors, and can
melt if near hot exhaust or components.
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Flow- and pressure-controlling devices need at least 0.14 MPa
(20 psi) pressure drop across them to operate properly. Source
pressures and capacities must be high enough to ensure this.
Flame ionization detectors must have dedicated air supplies.
Pressure pulses in lines shared with other devices will affect
operation.
Supply tubing diameter depends upon the distance between the
supply source and the GC and the total flow rate for the
particular gas. One-eighth-inch tubing is adequate when the
supply line is less than 4.6 m (15 feet) long. Use larger diameter
tubing (1/4-inch) for distances greater then 4.6 m (15 feet) or
when multiple instruments are connected to the same source.
You should also use larger diameter tubing if high demand is
anticipated (for example, air for an FID).
Getting Started