Teledyne GC-Pro/TCD - Gas Chromatograph - Manual (Page 44)

Installation GC-ProTCD
Teledyne Analytical Instruments 30
tube, “chasing” the red glow (and hydrocarbon deposits) down to the
open end of the tube. Cap the tubing while not in use with suitable non-
contaminating caps.
All sample, calibration, and supporting gas lines, which deliver gas
to the analyzer, must be decontaminated before connection; vent lines do
not.
When connecting the various gas lines to the system, be absolutely
certain that no “dead ends” are left; that is, no unused branch lines
should be left capped off, where pockets might form of material that is
not representative of the current contents of the line, or which might
keep contaminants from being purged out of the system.
CAUTION: THE GASES USED MUST BE OF THE HIGHEST
QUALITY, ULTRA ZERO GRADES, AS SHOWN
BELOW. FAILURE TO DO SO WILL RESULT IN
CONTAMINATION AND FAILURE TO DETECT AT
THE REQUIRED ACCURACY.
Normally, two supporting gases (carrier gas and span gas) will be
required to operate the analyzer. The recommended composition for the
span gas is specified Appendix C: Addendum and Testing Results. Zero
calibration is handled electronically and does not require a separate gas
source. The support gases should be supplied from cylinders that are
equipped with an appropriate type of regulator.
CAUTION: UNDER NO CIRCUMSTANCES SHOULD YOU
EMPLOY A REGULATOR THAT IS NOT EQUIPPED
WITH A METALLIC DIAPHRAGM ANYWHERE IN THE
SYSTEM.
The regulators should be inspected prior to installation to be sure
that they are oil-free. Failure to comply with these directives will result
in a constant drift in analyzer output, as organic compounds will outgas
into the plumbing system at a rate that is related to the ambient
temperature. Use 316 stainless steel, dual-stage stainless steel diaphragm
regulators; shutoff valves should be used downstream from each
regulator.
Place the supply cylinders as close to the analyzer as possible, and
connect to the analyzer with new tubing. Be sure that all plumbing
connections are free of leaks.
Note: Use only stainless steel tubing throughout the system.