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 4
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 4 Sampling methods
1
Air
2
Sample flow
Plumb the instrument
Figure 5
shows the instrument and the water weir controller connection to the water system. Make
sure that the tubing length is 3.05 m (10 ft) maximum. Tubing lengths longer than 3.05 m (10 ft) will
cause the larger particles to "drop out" of the sample. This will decrease the accuracy of the particle
size reading.
1.
Install a plumbing tap with a shut-off valve for the instrument. Refer to
Figure 5
, item 5.
2.
Install a quick-connect fitting on the shut-off valve.
3.
Install a quick-connect fitting to one end of the 3.05 m (10 ft) length of the 1/4-in. black semi-rigid
tubing supplied with water weir. Refer to
Figure 5
, items 2 and 8.
4.
Install the nut and then the compression fitting to the other end of the 3.05 m (10 ft) length of the
black tubing. Refer to
Figure 5
, configuration "B".
5.
Attach the fitting to the inlet on the water weir. Refer to
Figure 5
, item 10.
6.
Connect the quick-connect fitting to the plumbing tap (shut-off valve) of the water source. Refer to
Figure 5
, items 2 and 5.
7.
Install a quick-connect fitting to one end of the 18-in. length of 1/4 in. black flexible tubing
supplied with water weir. Refer to
Figure 5
, items 2 and 11.
English
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