Sample Line Guidelines; Connect The Sample Stream - Hach WPC-21 Manual Del Usuario

Figure 6 Plumb the instrument
1 Sample line fitting
2 Drain line fitting

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 the sample line into a larger process pipe to minimize interference from air bubbles or pipeline
bottom sediment. A sample line that goes into the center of a process pipe is best.
Figure 7 shows examples of good and bad methods of sample line installation into a process pipe.
Keep the sample line as short as possible to decrease analysis delay. Sediment can collect in long
sample lines.
Figure 7 Sampling methods
1 Air
14 English
3 Plastic nut
4 Ferrule, 6 mm
2 Sample flow