Note: Descriptions are shown in the official language in which they were submitted.
1 BACKGROU~D
The present invention relates generally to wetting
agent injection systems and more specifically to wetting
agent injection systems for firefighting apparatuses.
It has been established for some time that water
treated with a wetting agent is more effective on a Class
A fire where good water penetration is needed to reach and
extinguish the seat of the fire. Prior to the present in-
vention, wetting agents were poured into the desired amount
10 of water located in the tank of a water truck, and the water
was then pumped onto the fire. Many disadvantages flow from
this technique. Specifically, it was necessary to always
have a water tank truck available for this purpose. For
example, when water was being supplied by a fire hydrant or
15 by drafting operations such as taking water from a lake or
a pond, it was necessary to first pump the water into the
water tank, apply the wetting agent, and then pump the
treated water from the water tank onto the fire. Other
disadvantages also arise from having the wetting agent in
20 the tank. First, some wetting agents are corrosive in
nature and will, in time, rust out the tank. There~ore,
much flushing of the water tank is required to clean out
the tank to rid it of any wetting agent residue. Further,
any wetting agent left in the tank when mixed with fire-
25 fighting foam breaks the foam down defeating the effective-
ness of the fireighting foam. Therefore, a need has arisen
for a wetting agent injection system for injecting wetting
--2--
~i~
J 2~641
1 agents into the suction side of the pump which then mixes
with the water within the pump and as it travels through
the hose line rather than requiring the mixing of the
wetting agent in a water holding tank.
SUMMARY
The present invention solves these and other
problems in firefighting by providing, in the preferred
embodiment, a wetting agent injection system utilized with
firefighting apparatus having a positive pressure pump.
Specifically, the injection system includes a supply tank
in fluid con~unication with a solenoid valvet which in
turn is in fluid communication with the suction side of
the positive pressure pump. In its most preferred form,
the system is electro-pneumatically controlled. Specifically,
the supply tank is pressurized and can be regulated to force
the wetting agent from the supply tank through the fluid cOIl~
duit to the suction side of the pump when the solenoid valve
is open. Detectors for detecting flow in one or more discharge
lines of the pump and supply level detectors for de~ecting
the condition of the supply tank are provided for activating
an electric solenoid valve permitting the wetting agent to
be injected into the pump due to the pressurized condi~ion of
the supply tank.
Thus, it is an aim of the present invention
to provide a novel wetting agent injection system.
It is also an aim of the present invention to
--3--
12Q~641
1 provide such a novel wettin~ agent injection system utilized
with firefighting apparatus having a positive pressure pump.
It is also an aim of the present invention to
provide such a novel wetting agent injection system where
the wetting agent ~s introduced into the suction side of
the pump and mixes with the water within the pump and as
it travels through the discharge lines.
It is also an aim of the present invention to
provide such a novel wetting agent injection system which
allows automatic operation.
It is also an aim of the present invention to
provide such a novel wetting agent injection system which
requires minimal adjustment or attention.
it is also an aim of the present invention to
provide such a novel wetting agent injection system which
has an automatic shutdown feature when the wetting agent
holding tank is émpty or when flow through the discharge
lines is stopped.
It is also an aim of the present invention to
provide such a novel wetting agent injection system which
has few moving parts and which requires no expensive motor
or air driven wetting agent pumps.
These and further aims and advantages of the
present invention will become clearer in light of the follow-
25 ing detailed description of an illustrative embodiment ofthis invention described in connection with the drawing.
12~64~
1 DESCRIPTION OF THE DRAWING
The illustrative embodiment may best be described
by reference to the accompanying Figure 1 showing a schem-
atic/diagrammatic view of a wetting agent injection system
according to the preferred embodiment of the teachings of
the present invention.
The figure is drawn for ease of explanation of
the basic teachings of the present invention only; the exten-
sions of the figure with respect to number, position, rela-
tionship, exact electrical connection, precise logical con-
figuration, and dimensions of the parts to form the preferred
embodiment will be explained or will be within the skill of
the art after the following teachings of the present invention
have been read and understood.
DESCRIPTION
A wetting agent injection system according to the
teachings of the present invention is shown in the drawings
and generally designated 10. System 10 is preferrably utilized
20 with fire fighting apparatus having a centrifugal or positive
pressure pump 12 in fluid connection with hose lines, shown
in the most preferred form as including two hose lines 14
and 16. It can then be appreciated that the appropriate
firefighting apparatus can include fewer or more hose lines,
25 as desired.
System 10 includes a wetting agent supply tank
18 in fluid communication by means of conduit 20 to
--5--
~2~)~L6~
1 wetting agent filter 22. Filter 22 is in fluid communication
by means of conduits 24 and 26 to solenoid valves 30 and
32, respectively. Solenoid valve 30 is in fluid communication
by means of conduit 36 to metering valve 38. Solenoid
valve 32 is in fluid communication by means of conduit 40
to metering valve 42. In their most preferred forms, metering
valves 38 and 42 are adjustable needle type valves. Metering
valves 38 and 42 are in fluid communication through check
valve 43 by means of conduit 44 to the suction side of
pump 12. Check valve 43 prevents water from flowing into
or through valves 3~ and 42 from pump 12.
Due to the corrosive nature of some wetting agents,
all components in contact with the wetting agent such as
tank 18, conduits 20, 24, 26, 36, 40, and 44, filter 22, and
valves 30, 32, 38, 42, and 43 should be made of a non-ferrous
material or a good grade of stainless steel to counteract
the possible corrosive effects of the wetting agent.
In addition to the intrinsic control created by
the length and diameter of conduits 20, 24, 26, 36, 40,
and 44, the size and adjustment of valves 30, 32, 38, 42,
and 43, and the size of filter 22, system 10 further includes
control apparatus 46 for controlling the flow and flow amount
of the wetting agent. Specifically, preferred system 10 includes
provision for pressurizing supply tank 18. Particularly,
system 10 includes a conduit 48 in fluid communication
between supply tank 18 and an air supply, such as the air
supply of the fire fighting apparatus or a compact air
--6--
12~164~
1 compressor. Conduit 48 includes a shut-off valve ~9 for
stopping air pressure into tank 18 and for removing any
residual air pressure in tank 18 when it is desired to
depressurize tank, such as in the case of refilling. Conduit
48 further includes an adjustable regulator 50 for regulating
the amount of air pressure allowed within supply ~ank 18
and a pressure gauge 52 for visually indicating the pressure
within tank 18.
It can then be appreciated that the wetting agent
flow from tank 18 into system 10 can be regulated by regulating
the air pressure into tank 18 by utilizing regulator 50
according to the particular desires of the user. The pressure
requirements for the proper flow of wetting agent is determined
at the time of installation and is based upon several factors
including the wetting agent viscosity, amount of wetting agent
to be injected, the intrinsic controls of system 10, the ad-
justment of valves 30, 32, 38, and 42, and the residual pump
pressure. Also, adjustment of regulator 50 may be desired
depending on the source of water from which pump 12 is pumping
from. The pressure requirements will be within the skill of
persons in the art after the teachings of the present inven-
tion are known.
Supply tank 18 should be strong enough to with-
stand an internal pressure of 150 psi and should have a
sufficient size to hold the desired amount of wetting agent.
For example, typically a one gallon ~ank will trea~ from
4800 to 48,000 gallons of water, depending on the intrinsic
--7--
~2Q~
1 controls created by the length and diameter of conduits 20,
24, 26, 36, 40, and ~4 and the size and setting of valves
30, 32, 38, and 42, whether the maximum gallons are being
pumped, and the air pressure being supplied to the supply
tank as compared to the pressure conditions existing on the
suction side of pump 12.
Furthermore, system 10 includes provision for
electronically controlling solenoid valves 30 and 32. Par-
ticularly, system 10 includes supply tank level indicator
56 shown in its most preferred form as a float switch.
Float switch 56 is in electrical connection to a logic
element shown in its most preferred ~form as a relay 68
including a switch 69 and a coil 58. Specifical~y, float
switch 56 is in electrical connection to coil 58 as by
wire 60. Further, float switch 56 is electrically con-
nected to ground 62 by means of wire 64. Coil 58 is
further connected to a power source 63, such as the 12 volt
battery of the firefighting apparatus, by means of wire 66.
Coil 58 acts upon normally closed switch contacts
69 of control relay 68. Switch 69 is in electrical connection
to power source 63 by means of wire 70 and is also in
electrical connection to coils 72 and 74 of second and third
logic elements 94 and 112 by means of wire 76. Coil 72 is
in further electrical connection to a flow detector shown
25 in its most preferred form as a flow switch 78 by means of .
wire 80. Flow switch 78 is in electrical connection with
ground 62 by means of wire 82. In a similar manner, coil
--8--
0~641
1 74 is in electrical connection with a flow switch 84 by means
of wire 86 and flow switch 84 is in turn electrically connected
to ground 62 by means of wire 88.
Coil 72 acts upon normally closed switch contacts
90 and normally open switch contacts 92 of control relay
94. Switch 92 is in electrical connection to power source
63 by means of wire 96 and is in electrical connection to
solenoid valve 30 by means of wire 98. Switch 90 of relay 94
is in electrical connection to power source 63 by means of
wire 100 and is electrically connected to solenoid valve 30 by
means of wire 102. Wires 98 and 102 can further include
an indicator light 104 for indicating activation of solenoid
valve 30. Solenoid valve 30 is electrically connected to
ground 62 by means of wire 106.
In a similar manner, coil 74 acts upon switches
108 and 110 of relay 112. Normally open switch 110 is in
electrical connection with power source 63 by means of wire
114 and is in electrical connection with solenoid valve 32
by means of wire 116. Switch 108 is in electrical connection
to power source 63 by means of wire 118 and is in electrical
connection to solenoid valve 32 by means of wire 120.
Wires 116 and 180 can further include an indicator light
122 for indicating activation of solenoid valve 32. Solenoid
valve 32 is electrically connected to ground 62 by means
of wire 124.
Wires 100 and 118 can further include an override
switch 126 and an indicator light 128 showing activation
_g_
12016~L
1 f the override switch. Wires 66, 70, 96, and 114 can
further include a start switch 130,and an indicator light
132 can be provided showing activation of start switch 130.
Now that the structure of the present invention
has been set forth, the operation and subtle features of
the present invention can be set forth and appreciated.
For purposes of explanation, a first condition will be
assumed, i.e., that wetting agent supply tank 18 is empty.
When tank 18 is empty, float switch 56 is normally open
thus not applying voltage to coil 58. Thus, coil 58 does
not act on normally open switch 69 of relay 68 and no
voltage is applied to coils 72 or 74 or to flow switches 78
or 84. Since switches 92 and 110 are normally open and are
not acted upon by coils 72 and 74, solenoid valves 30 and
32 are not energized and remain in their normally closed
position~ Thus, when coil 58 is not energized, voltage is
not applied to lights 104 and 122 of the control panel
indicating no flow of wetting agent.
It can then be appreciated that no matter what
the condition of flow switches 78 and 84, i.e., whether or
not flow is occurring through lines 14 or 16, due to the
lack of application of voltage to coils 72 and 74 as caused
by float switch 56 in the assumed tank empty condition,
solenoid valves 30 and 32 will not be activated, except
through utilization of override switch 126. Therefore,
system 10 has an automatic shut down feature whenever
holding tank 18 is or becomes empty, the first condition
--10--
~Z~69~1
1 of this operation explanation. Further, to reemploy the
system, it is only necessary to refill supply tank 18 placing
the system in a second condition of this operation explana-
tion discussed hereinafter.
If it is desired to energize valves 30 and 32
although the float switch 56 registers an empty tank, such
as when it is desired to completely empty system 10, voltage
can be applied to solenoid valves 30 and 32 by activation
of override switch 126 thus providing voltage from power
10 source 63 to ground 62 by means of wires 100, 102, 106, 118,
120, and 124 and switches 90 and 108.
Next, for purposes of explanation, a second condi-
tion will be assumed, i.e., that supply tank 18 has the
required amount of wetting agent such tHat float switch 56
is activated, thus moving from its open electrical position
to a closed electrical condition. Therefore, voltage is
applied to coil 58 from power source 63 through wires 60,
64, and 66 to gxound 62 through switch 130. Voltage on
coil 58 causes the contacts of switch 69 of relay 68 to
move from a normally open electrical condition to a closed
electrical condition. Therefore, voltage is applied through
coils 72 and 74 to flow switches 78 and 84 by wires 70,
76, 80, and 86. Thus, with tank 18 having the required
amount of wetting agent, system 10 is in its automatic
operation mode where system 10 will be activated automatically
when flow begin through discharge lines 14 and/or 16.
It can then be appreciated that there are two
--11--
~2al16~
1 further subconditions or possibilities; namely, water flow
through hoses 14 and/or 16 or no flow through hoses 14 and
16. For purposes of explanation, a first subcondition will
be assumed, i.e., that no flow occurs through either hose
14 or 16. With a no flow condition, flow switches 78 and
84 remain in a normally open condition preventing energiza-
tion of coils 72 and 74. Therefore, switches 92 and 110
remain in their normally open condition and do not provide
voltage to the normally closed solenoid valves 30 and 32.
It can then be noted that voltage can be applied to solenoid
valves 30 and 32 by engaging override switch 126 even
though flow switches 78 and 84 are in their normally open
condition in a similar manner as when it is desired to
override system 10 when tank 18 is detected as being empty
by float switch 56.
For purposes of e~planation, a second subcondition
will be assumed, i.e~, that flow is occurring through hose
14. With flow occurring through hose 14, flow switch 78
moves from its normally open condition to a closed condition
and the circuit between battery 63 and ground 62 is completed
as by wires 70, 76, 80, and 82. Thus, coil 72 is energized
moving switch contacts 92 from a normally open condition
to a closed condition. Therefore, voltage is applied to
solenoid valve 30 and indicator light 104 through switch 92
by wires 96, 98, and ]06 opening valve 30 allowing flow of
wetting agent from tank 1)3 through conduits 20, 24, 36, and
44 under action of the air pressure introduced into tank
~ZQ~64~L
1 18 by conduit 48. Coil 72 also moves switch contacts 90
from a normally closed condition to an open condition
preventing energization through override switch 126.
It should be appreciated that if supply tank 18
should go empty and/or should flow through hose 14 cease,
coil 72 will be deenergized, and thus will not act on switch
contacts 92 allowing switch 92 to move from its closed
position to its normally open condition and thus deenergizing
solenoid valve 30. In its deenergized condition, valve 30
moves from its open position to its normally closed position
preventing flow of wetting agent through conduit 36.
Flow switch 84, coil 74, relay 112, light 122,
and solenoid valve 32 operate in a similar manner as set
forth with respect to flow swiich 78, coil 72, relay 94,
light 104, and solenoid valve 30 and its operation will not be
repeated here. However, note that the operation of coil
74, flow switch 84, relay 112, light 122, and solenoid
valve 32 is independent of coil 72, flow switch 78, relay
94, light 104, and solenoid valve 30 allowing independent
operation of solenoid valves 30 and 32 such that valve 32
can be either in its open or closed postion no matter what
the condition of valve 30.
It can then be appreciated that system 10 provided
significant advantages over prior wetting agent introduction
systems. First, the wetting agent is introduced into the
pump and specifically not into a holding tank as was required
in the prior art. Thus, disadvantages of mixing within a
-13-
~IZ~1~64~
1 holding tank including the flushing of the holding tank
to remove any residue is not required. The only ~lushing
required of system 10 is running clear water through pump
12 to remove any residue therefrom. Further, system 10 is
not dependent upon the source of water since the wetting
agent is introduced into pump 12 and thus the water source
can be a fire hydrant, a drafting operation such as from
a lake or pond, or from a water holding tank.
Furthermore, introduction of the wetting agent
in the suction side of pump 12 insures a thorough mixing
thereof and a better mixing than may occur when the wetting
agent was simply dumped into a holding tank or introduced
into the discharge lines.
Additionally, during the initial stages of
attacking a fire, water penetration is of the utmost impor-
tance and thus the treatment of water by a wetting agent is
very important. However, at the initial stages of attacking
a fire, the pump operator is the busiest and prior to the
present invention, the introduction of wetting agent lnto
the water was delayed due to the disadvantages of prior
wetting agent introduction methods. Utilizing the present
invention, it is only necessary to activate switch 130 and
system 10 automatically operates and maintains itself.
Specifically, it should be noted that the wetting agent
can be filled in tank 18 and can be in a standby condition
if and when it is desired to treat water utilized in
fighting fires. Thus, system 10 will be in the second
-14-
L6~
1 condition of operation as set forth hereinbefore. When
water is being discharged through lines 14 and/or 16, the
flow is detected by switches 78 and/or 84 activating solenoid
valves 30 and 32 instantly as set forth in the second sub-
condition of the operation described hereinbefore withoutfurther assistance of the pump operator. Additionally,
should more or fewer discharge lines be employed, system
10 automatically adjusts the concentration of the wetting
agent according to the flow detection in each of the dis-
charge lines. Likewise, if supply tank 18 should go empty,system 10 is automatically deactivated by float switch 56
without operator assistance and to reemploy system 10, it
is only necessary to refill tank 18 with wetting agent.
Further, it can be appreciated that system 10
is particularly advantageous in its easy adaption for use
with one, two, or more discharge lines while utilizing a
single source of wetting agent. Further, activation of a
single switch 130 activates the entire system, and automatic
injection of the correct amount of wetting agent into the
pump is provided upon start o~ flow in the discharge lines
as they are placed into use.
Furthermore, it should be noted that metering
valves 38 and 42 may be adjusted for the estimated volume of
water which is expected to pass through their correspondiny
25 discharge lines 14 and 16. Discharge lines generally include
nozzles allowing throttling down of the flow of water. It
can then be appreciated that by throttling down the amount
12~641
l Of water flowing through the lines by the discharge nozzles,
a higher concentration of wetting agent within the water
flow may be obtained. Therefore, when a richer concentration
of wetting agent is desirable, such as during the overhaul
and mop up operation of fires, it is only necessary to
throttle down the discharge nozzle without any further
adjustments. Thus, less manhours are spent at the fire
scene and the problem of rekindling should be less frequent.
Likewise, system lO has few moving parts requiring
little maintenance and does not require expensive air or
motor driven pumps for the wetting agent. Further, very
little power is required in operating system lO. In the
most preferred form of the present invention, the power
sources for system lO utilized, i.e., the source of air
15 pressure for tank 18 and battery 63, are generally standard
equipment available on fire fighting apparatus, and thus
no separate power sources are required for system lO. Thus,
system can be inexpensively added to existing firefighting
apparatus. Additionally, system 10 is of a very compact
design utilizing only one and one-half cubic feet of space
in the preferred embodiment of the present invention allowing
its installation behind the driver's seat of a fire pumper.
It should be noted that there are no limiting factors con-
cerning mounting sites for system lO, except where extreme
low temperatures are encountered causing the wetting agent
to thicken and change its flow characteristics.
Now that the basic teachings of the present
-16-
~Z~
1 invention have been explained, many extensions and varia-tions
will be obvious to one having ordinary skill in the art.
For example, the normal conditions of relays 68, 94, and
112, switches 56, 78, 84, and solenoid valves 30 and 32
can be varied according to the particular desires of the
designer. For example, although solenoid valves 30 and 32
are shown in their most preferred forms as having a normally
closed condition and when activated move to an open condition,
the solenoid valves can be modified to be in a normally open
position and when energized move to a closed position, which
modification would then require other modifications in control
apparatus 46.
-17-
