Hach Polymetron 9611sc Installation Manual page 9

Figure 5 Sample and drain lines
1 Sample in (single-stream)
2 Shut-off valve
3 Y-strainer with filter
Drain line guidelines
Correct installation of the drain lines is important to make sure that all of the liquid is removed from
the instrument. Incorrect installation can cause liquid to go back into the instrument and cause
damage.
• Make the drain lines as short as possible.
• Make sure that the drain lines have a constant slope down.
• Make sure that the drain lines do not have sharp bends and are not pinched.
• Make sure that the drain lines are open to air and are at zero pressure.
Sample line guidelines
Select a good, representative sampling point for the best instrument performance. The sample must
be representative of the entire system.
To prevent erratic readings:
• Collect samples from locations that are sufficiently distant from points of chemical additions to the
process stream.
• Make sure that the samples are sufficiently mixed.
• Make sure that all chemical reactions are complete.
Connect the sample stream
Install each sample line into the center of a larger process pipe to minimize interference from air
bubbles or bottom sediment.
4 Non-adjustable pressure
regulator (set at 4 psi to protect
analyzer)
5 Sample bypass drain
6 Chemical drain
Figure 6 shows examples of good and bad installation.
7 Case drain
English 9