Class1 FoamLogix 2.1A & 1.7AHP REV D - Manual (Page 38)

FoamLogix, Model 2.1A and 1.7AHP Class “A”
Electronic Foam Proportioning Systems
38
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 FoamLogix 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 12: “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 Figure
4: “Pipe Size vs. Flow Rate,” on page 24, 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.
Table 13: Pipe Size vz. 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 14: “Typical
Reduced Size Sensor Piping Arrangement” on
page 39.
Excessive turbulence in the flow sensor may
produce unstable and inaccurate flow read ings.
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 FoamLogix 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 15: “Flow Sensor
Placement” on page 39.)
Pipe Size Minimun Recommend-
ed Straight Run Pipe
1-1/2” 9”
2” 12”
2-1/2” 15”
3” 18”
4” 24”