Chapter:
Topic:
INSTALLATION
Gas Supply Selection
Helium is the recommended carrier gas for all standard SRI installed
detectors. These detectors include: TCD, Fill, Pill, ECD, DELCD, FPD,
and NPD. If helium is unavailable, nitrogen is an acceptable carrier gas
alternative.
If
nitrogen is used
with
a
TeO,
the filament current switch
must
be
set
to
low
to
avoid filament damage.
Do
not use hydrogen or any
odter flammable gas
as
a
carrier
gas for any SRI
8610C
GC. These units
have electronic pressure control and a simple column or injection
port
leak
could release dangerously high levels of flammable gases. Somedetectors
and accessories require additional gas supply types for proper operation.
Argon/methane or nitrogen is required for ECDs as make-up gas. The
recommended make-up
gas
is argon/methane which provides the best
sensitivity and largest dynamic range for the ECD, but nitrogen is a readily
available, cost effective alternative (see the manual section on the ECD for
moredetai1s). Fills, FPDs, and NPDs
all
require bydrogen and
air
in order
to
create the combustible fuel mixture for the detector flame. Hydrogen is
an extremely flammable gas and must be bandied appropriately. Always
consult local safety regulatory agencies for proper procedures for haodling
compressed and/or flammable gases.
An
internal
air compressor is an
available SRI GC option as a source of
air.
GCs with a purge and trap
accessory
also
require some type of sparge gas. Generally helium
can
be
used as
both
a carrier and a sparge gas supply.
Methanizer accessories
require hydrogeo gas as a reactant in the catalytic reduction of
CO
andCo,
to04.
We recommend the use of medium
to
high quality gas sources for all
required gases in order to prevent any operational problems associated with
low quality
gas.
ECDs require an extremely pure carrier
gas
source of
99.9995% or higher. SRI GCs are equipped with small intemal molecular
sievepolishing filters on the carrier gas plumbing only to filter lowlevelsof
contaminants.
If
the quality of gas available is questiooable, an larger
external filter may
be
necessary to filter excess contaminants such as
moisture. Please
call
SRI technical support with any additional questions on
gas supplies or specialized applications.
Protective cap
"-
Content
~
and
status
~
Content
tag_" .... /
Jabot
/~
Typical
gas
cylinder
shovdt.
Note
that the protective
cap
is
in
place, protecting the valve
from damage. Cylinders are
clearly
labelled and
tagged
when
delivered
for
we.
In
some areas, cylinders are
color-coded
for
handling
safety
Gas valve -
:
\
Regulator
100
protective cap
is
removed oely after cylinder
is
in
place and secured by
at
least
ODe
chain or belt
IMPORTANT SAFETY NOTE
When handling gas cylinders, remember - never transport or move
a gas cylinder without
its
protective cap securely in place. Gas cylinders
can contain up
to
2700 psi of compressed gas.
If
the cylinder were to
suffer an accident causing the unprotected valve stem to be broken off, the
force of the escaping gas could convert the cylinder into a lethal projectile
capable of travelling hundreds of feet and penetrating structural walls.
Once the gas cylinder has been placed in the location where it
will
be
stored or utilized, it should
be
secured by means of a chain or belt
securely fastened to the wall or other foundation. One strap mayor may
not
be
adequate depending on the installation - consult local safety
regulations. Once the cylinder
is
in place and secured, the cap may
be
removed so that the aas oressure resulator mav
be
attached for use.
Strong belt
or chain
for •
securing
cylinder
to
structure
•
C:\MANUAL\CHPI'ERI\lNSTGASI.EPD
REV. 0&-Q6.96
