Alternative To Strainers; Maximum Unanchored Length; Routing The Suction Line And Strainer - Teledyne 5800 Installation And Operation Manual

2.7.1 Alternative to Strainers

2.7.2 Maximum
Unanchored Length
2.8 Routing the Suction
Line and Strainer
When sampling from high velocity streams with heavy
suspended solids, some field investigations suggest that more
representative samples are obtained without the strainer.
Consider attaching a short piece of thin walled aluminum tubing
to the end of the suction line; anchor the tubing so that the inlet
opens upstream. The aluminum tubing's thin wall will not
disturb the flow stream, and most sample analyses disregard
aluminum ions. Under most conditions, a pre-sample line rinse
removes any debris over the tubing entrance.
Table 2-2 lists maximum unanchored lengths for each type of
suction line. During a pre- or post-sample purge or line rinse, the
suction line is filled with air which might cause the suction line
and strainer to float. If the length of the suction line and strainer
exceeds the listed value, securely anchor the strainer.
Note
Even if the maximum length is not exceeded, it is a good idea
to anchor the suction line and strainer when sampling from
high velocity or turbulent flow streams.
Route the suction line so that it has a continuous slope from the
liquid source to the sampler. This helps to drain the line during
pre- and post-sample line purges and rinses. If a suction line
exposed to freezing climates does not fully drain, there is a risk of
liquid in the suction line becoming frozen. Frozen liquid will
cause the sample collection to fail. A warm sampling source can
usually prevent this, provided there are no traps or low spots in
the suction line. Some extreme situations may require more
protective measures, such as insulating the suction line, applying
heat tape, or adding a pump heater.
For representative samples, place the strainer in the main
current of the flow stream, not in an eddy or at the edge of flow.
Placing a strainer at the bottom may produce samples with
excess heavy solids and no floating materials, while placing it at
the top may produce the opposite conditions.
As with all such pumps, it relies upon liquid to cool working
components. If the sampler is programmed to pump in the
absence of liquid in excess of 5 minutes, excessive heat
buildup may damage the paddles, rollers, and housing. Ensure
that the liquid inlet is completely immersed. If the suction line
inlet is not completely submersed the sample will not be
accurate.
Isco 5800 Refrigerated Sampler
Section 2 Installation
CAUTION
2-17