Campbell PVS5120 Series, Instruction Manual

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PVS5120-Series Portable Samplers
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Sampling process:
1. High pressure air purge of intake hose.
2. Liquid is drawn into the metering chamber, up to the liquid sensing rod.
3. All excess liquid is purged from the system down to the level set by the
volume control tube
.
4. The sample is then released into either one composite container or one of
several discrete containers.
The sampling sequence begins with a high pressure air purge of the intake
assembly to remove residual liquid and obstructions. Upon completion of the
pre-purge cycle, the system converts to a vacuum state, drawing the sample
through the intake hose into the metering chamber. The system then
pressurizes, ejecting excess fluid back through the intake line until the
predetermined sample volume is achieved. The sample is then deposited under
pressure into the sample container while the post purge again clears the intake
line of any residual liquid. Purge time is a function of hose length and head
between the sampler and the sample source.
FIGURE 8-2 shows purge times for hose lengths up to 232 feet with one foot
of lift. This example is based on tests completed at 4500 ft above sea level.
There was only 1 foot of lift for all of the runs. Purge time was determined by
running the Auto Deploy routine for each hose length.
FIGURE 8-2. Purge time as a function of hose length
If the sampler is not able to draw a sufficient volume of fluid to complete the
circuit between the volume control tube and the conductivity rod, the unit
automatically initiates a second attempt. If the sample liquid still does not
touch the conductivity rod, the sampler purges to the level of the volume
control rod, and then drops the remaining liquid into the sample container and
returns response code 4 (vacuum time out error). The sampler waits till the
next initiation ( Run command) to try to collect another sample. When a
0
20
40
60
80
100
120
0 50 100 150 200 250
Pu
rg
e
Ti
m
e (
sec)
Hose Length (ft)