Campbell Scientific PVS4100/4120/4150 Portable Automatic Samplers - Manual (Page 31)

3-1
Section 3. Operation
3.1 Operating Sequence
3.1.1 Sampling Sequence
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.