Appeal No. 2000-1300
Application 08/853,581
for use in fire fighting, wherein foam or other type chemicals
are added to the water used for fighting a fire. In Figure 1,
chemicals from tank (12) are added to the water passing through
pump (P) based on the flow measured at output hoses (3, 4, 5)
providing a feedback to amplifier (6) and potentiometer (8).
The potentiometer is set to a desired ratio between the
chemicals and total flow. A signal proportional to total flow
is connected to the potentiometer (8), the output of which is
connected to amplifier (9). The output of amplifier (9) is
connected to electric motor (10) which operates a pump (11) that
pumps foam or other chemicals from the tank (12) to the pump
(P). As noted in column 2, lines 18-21, by setting the desired
ratio on the potentiometer (8) the desired ratio will be
maintained by the amplifier (9) controlling the speed of the
electric motor (10), which in turn controls the chemical pump
(11). An alternative embodiment is seen in Figure 2 of
McLoughlin. In the alternative embodiment, instead of
controlling an electric motor and pump as in Fig. 1, the servo
amplifier (9’) controls a motor (22) which controls a valve
(13), and it is the valve (13) which controls the ratio of
chemicals to total flow.
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Last modified: November 3, 2007