Chapter:
Topic:
PURGE-AND-TRAP
Connecting The On-Line Liquid Sampler To
An
Existing SRI Purge-and-Trap
The on-line liquid sampler accessory for theSRI purge-and-trap sampling system is an external
unit
designed
to
deliver, purge, andevacuate a liquid sample from theSRIpurge-and-trap sample
concentrator, on a repetitive basis, under data system automation.
This
permits
theunattended
monitoring ofany
fluid
effluent or stream onacontinuous
basis.
In
order
to
operate this accessory,
the following installation steps are required:
1.
Locate
the three
cables exiting the rear of theon-line liquid sampler. Find andconnect the AC
supply cable
to
anavailable ACwall
outlet,
A second cable terminates
in
a remote control wand for
the optional manual operation of the liquid sanopling valve. Operation of this control is by means of
the toggle switch provided. Make sure that the valve is in the LOAD position before proceding. The
third cable is the control cable
for
the sampling valve actuator. Of the 5 wires in this cable, only
three
are
used
(green, black, and red) for control of the valve loading and injection. Connect these
wires to an unused relay (or relays) in your
data
system(green is common).
2. Four ports are located on the front panel of the on-line liquid sampler. The upper left port is the
liquid
sample.inlet,
where
the
incoming sample flowis
connected,
The lower left
port
is the sample
outlet for liquid that
has
passed through
the
5ec sampling loop to the
drttin
line. Route the
drttin
away from the
GC
and any electrical devices and connections. The upper right
port
is thesparge gas
inlet. Disconnect the sparge
gas
supply line from theGC to the original purge-and-trap sparge head,
and connect it here. The lower right
port
is the sparge gas outlet from the internal liquid sampling
valve. This outlet is directed
to
the inlet of the modified sparging head provided with this unit.
3. Remove the original purge-and-trap sparging head from the GC purge-and-trap sampler, and
replace it with the sparging headprovided with the on-line liquid sampler. Note that it is equipped
with
two
lines that enter the sparge head through
the
top.
From
modified
One line delivers the
liquid sample, propelled by the
flow
=
s:;r:~
sparging
bead
to
of sparge
gas
through the liquid sampling valve.
The
second
sampler (carries
soleacid-ccatrolled
line
is
the drain line that carries spent sample from the
sample into
--+-
~
drain line
sparging head to
the
drain line,
after passing through a
modifiod
solenoid-controlled valve that controls draining.
pu<ge-0Dd-tnp
sparging
head)
Liquid
sample
inlet
J~~S~P";j}g~
"",lot
"""l'mg
sample-laden
gas
to
purge-and-trap
concentrator
LiqWd
sample
outlet
-f?iWli!l
(dnin)
Spuge gas
W@!iB'r
outlot
(to
sparge
head)
FRONT VIEWOF ON·LINE
LIQUID
SAMPLERACCESSORY
MODIFIEDSPARGE
HEAD
FOR
PURGE-AND-TRAP
SAMPLER
