HALE SmartFOAM 1.7AHP, Description, Installation And Operation Manual

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Page 40
SmartFOAM
WATERWAY CHECK VALVES
Check valves in the waterway, rated at 500 PSI (34.5
BAR), are required to keep foam solution out of the main
pump and allow pump priming without drawing foam into
the piping.
Using double check valves, separated by at least
6” to 8”
(152 to 203mm) of pipe before the foam injection point,
ensures that the pump and tank water remain
uncontaminated.
FLOW SENSOR
The Hale SmartFOAM flow sensor is specially designed
to enable quick and easy sensor inspection and
maintenance. The flow sensor paddle wheel is installed
on a saddle clamp or weld fitting to the foam-capable
discharge piping of the apparatus.
In horizontal piping runs, the flow sensor is mounted
within the range shown in Figure 19
: Flow Sensor Tee
Position Range .
Figure 19 : Flow Sensor Tee Position Range
When selecting a flow sensor, it is important to consider
the minimum and maximum flow requirements during
operation. Refer to the Table 4
: Pipe Size versus Flow
Range , for the proper pipe size for flow range desired.
The flow sensor is installed in the piping before the foam
concentrate injection point.
This is true in applications where the foam system needs
to supply a
3” (76mm) deck gun, as well as a 1”
(25.4mm) booster line.
Pipe Size
Minimum Recommended
Straight Run Pipe
1-1/2 in (38.1 mm) 9 in (228.6 mm)
2 in (50.8 mm) 12 in (304.8 mm)
2-1/2 in (63.5 mm) 15 in (381 mm)
3 in (76.2 mm) 18 in (457.2 mm)
4 in (101.6 mm) 24 in (609.6 mm)
Table 6 : Pipe Size versus Minimum Straight Run
Pipe size for flow sensor mounting must be selected to
provide accuracy at the lowest flow rate. Mounting the
flow sensor in a short section of pipe, one pipe size
smaller (e.g.,
4” to 3”; 3” to 2-1/2”, etc.), provides better
accuracy at the lower flows.
Refer to the Table 13:
“Pipe Size vs. Minimum Straight
Run” for pipe size. Selecting the next smaller pipe
permits reducing the straight pipe run the required
distance prior to the flow sensor paddle wheel.
In the short length of reduced pipe pressure loss is
minimal and there is minimal pressure loss through
elbows and fittings. See Figure 20
: Typical Reduced
Size Sensor Piping Arrangement .
Excessive turbulence in the flow sensor may produce
unstable and inaccurate flow readings. The length of
straight pipe prior to the flow sensor must be sufficient to
reduce any turbulence in the pipe.
The following guidelines help attain the best readings,
and maintain Hale SmartFOAM system accuracy.
1. A minimum of 6 times the pipe diameter of
straight run pipe without any fittings is necessary
prior to the flow sensor paddle wheel. (See
Figure 21
: Flow Sensor Placement ).
2. The downstream piping length is not as critical,
but there must be a short length of straight pipe
with no fittings or valves immediately after the
flow sensor paddlewheel. Two to three times the
pipe diameter is recommended.
3. Do not mount a flow sensor directly after an
elbow or valve. Valves create severe turbulence
when they are
“Gated”.