Note: Descriptions are shown in the official language in which they were submitted.
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Method and high-capacity apparatus for producing fire
fighting foam and foam expanding spreading device
The invention relates to a method and a high-capacity
apparatus for producing fire fighting foam and a foam
expanding spreading device which method and apparatus able
to produce quickly a bulk of fire fighting foam and to
discharge the produced fire fighting foam onto a large
surface in a layer of uniform thickness, which method and
apparatus can particularly be used as fire extinguisher of
tanks containing liquid fluids especially liquid
hydrocarbons and to extinguish fire thereof.
In course of the method according to the invention a
composition is prepared consisting of foaming agent, water
and gaseous medium.
It is well-known that air-foams are generally used to
extinguish fire of storage tanks containing inflammable
liquids, especially liquid hydrocarbons.
It is typical of the known production methods of such fire
fighting foams that they are produced on the spot during
the process of extinguishing, using means and energy
available there at that time. Foaming agent kept on store
on the spot or conveyed there by the firemen after the
fire has broken out is used for producing the foam,
aqueous solution of the foaming agent is produced, and,
using appropriate means to increase its pressure, the
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foaming agent solution is conveyed to the foam-generating
head through appropriate pipes. The streaming foaming
agent solution is mixed with air in the foam-generating
head and it becomes foaming there, the process of foaming
uses up the kinetic energy of the solution, and the foam
is directed to the place of application.
It is also known that foam fire extinguishing devices used
at storage tanks or storage tank farms containing
inflammable liquids are fixed or semi-fixed fire
extinguishers.
Semi-fixed fire extinguishers comprise pipelines or a
pipeline-network conveying the foaming agent solution from
the inlet place to the storage tanks, one or several foam-
generating heads, foam supply pipeline(s), foam
introducing device(s). Separate pumps (firefighting
trucks) are necessary to ensure the streaming of the
foaming agent solution. The foaming agent used for
producing the fire fighting foam is taken to the spot
after the fire has broken out, the solution can be
prepared and the fire fighting foam can be produced only
afterwards.
In addition, fixed fire extinguishers have a solution
supply centre, a so called extinguishing centre as well.
The extinguishing centre is equipped with a ready-to-use
foaming agent storing tank, water supply connection taps
to gain water or a water-reservoir of the required
capacity, proportioners to mix the foaming agent and pumps
to establish the required pressure, and these pumps are
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connected to the pipeline of the foaming agent solution
with appropriate valves inserted.
Both at fixed and semi-fixed fire extinguishers the fire
fighting foam is applied to the surface of the liquid in
the same way. At solutions where the foam is introduced in
the tank at the rim of the tank , e.g. at fire
extinguishers presented in patent specifications USP
4.893.681 and USP 4.148.361, there are usually more than
one foam introducing places along the circumference of the
tank. There are foam introducing appliances with foam
chambers or foam boxes situated at the foam introducing
places, as described in Swiss patent specification No.
676.553, foam deflectors are used to direct the foam
stream to the surface of the liquid or to the inner wall
of the tank. If the distance between the foam deflectors
and the surface of the liquid is larger than a given
maximum value, foam sliders equipped with guide- and
damping-plates are used to direct the foam to the surface
of thelliquid and to reduce the velocity of the foam
flowing out.
Further, there are solutions with devices to let the fire
fighting foam under the surface of the liquid in the tank
or right to the surface of the liquid at some given
places, an example for the former one is described in
patent specifications USP 4.664.199, USP 5.377.765 and USP
5.464.065, an example for the latter is presented in
patent specification USP 5.573.068.
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The above described solution, where the fire fighting foam
is produced when used on the spot, that is, at the place
and at the time of fighting the fire, has several
disadvantages as regards both the method and the fire
extinguisher apparatuses.
The most important disadvantage is that there is a long
period of time between the inflammation and the begin of
extinction of the fire. Usually it takes about 10 minutes
to 2 - 3 hours from the detection of the fire till
starting to extinguish it to complete the fire
extinguisher system, produce the foaming agent solution
and then the fire fighting foam from the foaming agent
available on the spot or taken to the spot just that time,
and to fill and activate the system to start producing the
foam. Further, after the extinguishing of the fire has
been started, it also takes significant time to produce
enough foam to form a foam blanket of the required
thickness and to spread this amount of foam in uniform
thickness on the surface of the burning liquid. During
this time the damage caused by the fire is permanently
increasing regarding both the material destroyed and the
growing damage done to the otherwise valuable tank, while
the environment is also being permanently polluted. In
order to indicate the magnitude of the damage and its
being proportional with time, we present an example. The
surface of a tank of 30000 m' is about 2000 m2, the
burning-rate constant of petrol is 7 mm/min, so
approximately 14 m3 petrol is burnt in the fire every
minute. In addition to the loss caused by the destruction
of such an amount of petrol, the released heat also
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endangers the surrounding establishments, and if it is a
tank farm, the other tanks are also considerably
endangered.
It is a further important disadvantage that the
reliability of the process of foam production is low, as
foam production may be reduced or made impossible by a
possible gag of the narrow flow cross section of the
nozzle of the foam generating injector due to
contamination with dust or dirt, or by tapering of the air
inhausting holes, e.g. getting obstructed with tree-
leaves. It is a further disadvantage that foam-volume flow
and foam intensity is limited. The basic reason of this
limit is that the foam is generated via using up the
kinetic energy of the foaming agent. Nearly the entire
pressure causing the solution to flow drops at the foam
generating head, the pressure of the foam ejected from the
foam generating head is close to the atmospheric pressure,
and it drops to the atmospheric pressure in the foam
supplylpipeline, hence the limit of foam production is
determined by the upper limit of the transporting capacity
of the device generating the flow of the solution, e.g.
the capacity of the pump. A further limit is set by the
narrow cross section of the nozzle used for foam
production. A further disadvantage of the method is the
varying quality of the foam, as the quality of the fire
fighting foam produced as described above is varying
depending on the actual flow conditions, reducing the
effectiveness of extinguishing the fire.
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As regards fixed extinguishers, where all the components
necessary for producing the fire fighting foam are
available and all the equipment is stored in a ready-to-
use status on the site of the possible fire, near the
storage tank of the inflammable liquid, usually at the
edge of the tank farm, it is a further disadvantage that
the foaming agent solution is started to be produced when
it is used, and it is produced until the fire is safely
extinguished. Not only the price of the installation of
such a fixed fire extinguisher is quite high, but the
required bulk of foaming agent to be stored on the spot
requires significant investment as well.
As regards semi-fixed fire extinguishers, it is a further
disadvantage that as it is only the pipeline-network
conveying the foaming agent solution, the foam generating
heads, the foam supply pipelines and the foam introducing
devices that are settled on the spot, and in case of fire,
the foaming agent concentrate or the foaming agent
solution is taken to the spot with a transport vehicle, it
is mixed with water on the spot using the instruments of
the transport vehicle, and it is pumped into the settled
pipeline network with pumps ensuring the required
pressure, the extinguishing of the fire can be started
only with significant delay, and in certain cases the time
lost can not be regained.
A further disadvantage of the above described fire
extinguishers in connection with the former problems is
that the foam let to the surface is uneven. The known
method of letting the foam to the surface at certain
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places along the circumference of the tank or discharging
the foam from the foam box does not form a foam blanket of
uniform thickness, and it takes long time till the foam
emitted forms a foam blanket entirely covering the surface
of the liquid. The part of the surface not covered with
foam keeps burning during this long time and the foam may
be spoiled at the edge of the foam blanket, therefore the
process of extinguishing drags out.
It is a further disadvantage that, as the foam produced in
the foam generating head and conveyed through the foam
supply pipelines is used immediately after leaving the
foam supply pipeline, and it is used up when being
applied, it is practically impossible to reduce the
unsteadiness of foam generation or to modify the quality
of the foam during operation, considering that usually
there is a surface burning with high flames where the foam
is emitted. Hence the quality of the foam produced and
used when extinguishing the fire is determined by the
parameters specified in advance and the actual conditions
of foam generation, and it is not always the optimum for
the given fire.
The major disadvantages of the above described solutions -
the set-up time before starting extinguishing, the
unsteadiness of foam generation, the fact that the foam is
generated via using up the kinetic energy of the flowing
solution, the resulting limited intensity of the foam, the
incalculable quality of foam and the slow spreading of the
foam - made it necessary to seek for a solution where the
foam, that is otherwise suitable for fighting fire, can be
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produced and directed to the place of application without
the disadvantages listed above.
The fundamental idea of the invention is that the
disadvantages described above can be attributed to the
simultaneity of generating and applying the foam. The
basic idea of the invention is that if the production and
application of the fire fighting foam is divided into two
separate actions, that is, if the generation and the
conveyance of the fire fighting foam is separated in a way
that the generation of the foam is independent from its
flowing, and we store the energy necessary for the
conveyance of the foam together with the essentially ready
foam in the form of pressure energy, all these make it
possible to produce foam of uniform quality that can be
better influenced than in case of the known methods, and
to adjust the quantity emitted, which makes the extinction
of the fire quick and economical. It is a further
discovery that we can store the fire fighting foam
produced with the method in a device that is connected to
the known foam conveying and foam emitting devices,
forming this way a fixed fire extinguisher that is able to
supply fire fighting foam immediately in case of fire.
A further discovery leading to the invention was that foam
can be emitted in a smooth manner within a short time with
a device where the foam is emitted not at a single point,
but along a longer section, preferably along the
circumference of the surface of the lictuid or the side-
wall of the tank etc. at the same time, the device being
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able to emit the same amount and quality of foam at any
point of emission along the section.
In course of the fire fighting foam production method
according to the invention, which is a solution for the
problem, a composition is prepared consisting of foaming
agent, water and gaseous medium. The essence of the method
is that the composition is prepared via dissolving or
emulsifying the components in one another under
overpressure, the composition prepared this way is stored
under overpressure at the required place for the required
period of time, transported if necessary while the
overpressure is maintained, and it is expanded via
decompressing it on the spot and at the time of
application.
In course of implementing the method of the invention the
water-soluble gaseous medium can preferably be carbon-
dioxide: For solving the gaseous medium, the overpressure
is chosen to be at least 10 bar, preferably more than 15
bar. Dissolution is made at room temperature. It is quite
advantageous to complete the solution in a way that liquid
carbon-dioxide is absorbed in water. If water-insoluble
gases, e.g. halogenated hydrocarbons are used, the gaseous
medium is to be dispersed in the foaming agent or the
aqueous solution thereof at a pressure of 10 - 40 bar,
preferably above 16 bar. In order to make dispersion more
uniform, known emulsifying agents indifferent against the
foaming agent can be used.
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The ready-to-use fire fighting foam is generated when the
composition is released to the atmospheric pressure, by
expansion of the gaseous medium dissolved or dispersed in
the composition, via certain inflation of the generated
bubbles as a result of the decrease of overpressure. As
the final step of foam production, the composition under
overpressure is let out to atmospheric pressure preferably
at the place of application, above or below the burning
surface of the liquid, therefore the fire fighting foam is
immediately used on the spat when it takes its final form,
and the apparatus producing the foam can be considered as
a fixed fire extinguisher.
The essence of the apparatus suitable for producing fire
fighting foam being a solution for the problem is that it
comprises a high-pressure foam source, a foam expanding
spreading device and a pressure resistant pipeline
connecting the high-pressure foam source with the foam
expanding spreading device .
A preferable, automatic embodiment of the apparatus
comprises a valve inserted in the pressure resistant
pipeline, preferably a remote controlled valve.
The embodiments of the apparatus of the invention can be
built up to different extent, depending on the demand.
It is an advantageous embodiment where the high-pressure
foam source of the apparatus has a high-pressure tank
containing the composition, and the pressure resistant
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pipeline is connected to the opening of the tank with a
main valve inserted.
If greater extent of foam is to be produced, it is an
advantageous embodiment where the high-pressure foam
source of the apparatus comprises a high-pressure tank
containing water with foam generating gas absorbed in it,
a foaming agent container and a mixer, the (pressure
resistant) high-pressure tank is connected to one inlet of
the mixer with a stop-valve inserted, and the foaming
agent container is connected to the other inlet of the
mixer, while the discharge mouth of the mixer is connected
to the pressure resistant pipeline directly or with a
second valve inserted.
If very great extent of foam is to be produced, e.g. to be
used at a tank farm, it is an advantageous embodiment
where the high-pressure foam source of the apparatus
comprises an absorbing vessel and a liquid or gaseous foam
generating gas container connected to one inlet of the
absorbing vessel directly or with a pressure controller
inserted, a mixer with a foaming agent container connected
to one of its inlets, the other inlet of the absorbing
vessel is fashioned in a way that it can be connected to a
water supply, the outlet of the absorbing vessel is
connected to the other inlet of the mixer, and the outlet
of the mixer is connected to the pressure resistant
pipeline.
At an other advantageous embodiment to be used if very
great extent of foam is to be produced, e.g. at a tank
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farm, the high-pressure foam source of the apparatus
comprises an absorbing vessel and a liquid or gaseous foam
generating gas container connected to one inlet of the
absorbing vessel directly or with a pressure controller
inserted, a mixer with a foaming agent container connected
to one of its inlets, the other inlet of the mixer is
fashioned in a way that it can be connected to a water
supply, the outlet of the mixer is connected to the other
inlet of the absorbing vessel, and the outlet of the
absorbing vessel is connected to the pressure resistant
pipeline.
If the apparatus is used at a tank farm, the pressure
resistant pipeline of the apparatus branches and a
disconnecting valve is inserted in each branch of the
pipeline.
Another a subject of the invention is a foam expanding
spreading device to be used for discharging fire fighting
foam onto a large surface in a layer of uniform thickness.
The essence of the first embodiment of the device to be
primarily used at applications of lower output demand is,
that it comprises an admission opening and a discharge
mouth, a tubular distributing body suitably forming a
closed loop of tubes, preferably of torus shape, the
discharge mouth, suitably a slit or a set of holes, is
situated on the nappe of the tube along its length,
preferably along its generating line. If the device is a
longer one, it is an advantageous embodiment where the
discharge mouth, suitably a slit or a set of holes, is
formed in a way that its size per unit length of the tube
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is growing according to the distance from the admission
opening .
The essence of the second embodiment of the foam
expanding spreading device to be used for discharging
fire fighting foam onto a large surface in a layer of
uniform thickness, to be primarily used at applications of
higher output demand, is that it comprises an admission
opening and a discharge mouth, a tubular distributing body
suitably forming a closed loop of tubes, preferably of
torus shape, a suitably tubular high-pressure receiving
chamber preferably forming a closed loop of tubes,
preferably of torus shape, mostly arranged in a way that
the torus shaped distributing body is concentrically
surrounded by the torus shaped high-pressure receiving
chamber, the distributing body is connected to the high-
pressure receiving chamber with hydraulically balanced
feeding, and the discharge mouth, suitably a slit or a set
of holes, is situated on the nappe of the tubular
distributing body along its length, preferably along its
generating line, and the admission opening is the
admission opening of the high-pressure receiving chamber.
The main advantage of the method according to the
invention is that the fire fighting foam is generated when
the composition of the foaming substance is released from
the apparatus to the space of atmospheric pressure by
expansion of the compressed gaseous medium in the
composition, therefore the foam of the required quality is
surely produced. It is a further advantage that the risk
of failure is very low as there is no nozzle-like
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narrowing in the pipelines. The tanks storing the
composition with the gaseous medium absorbed in it are
pressurised energy-storing devices, hence their operation
usually does not depend on external factors, e.g.
intermission of electric supply etc, and the set-up time
before starting extinguishing is negligible.
At apparatuses storing small amount of composition (50-100
m3) containing compressed gaseous medium absorbed in it,
successful extinction of the fire is ensured even in total
lack of fire water system.
A further significant advantage of the method and
apparatus of the invention is that it is suitable for
realising very high foam intensity. If we want to empty a
tank filled with the required quantity of composition of
16, 25 or 40 bar operational pressure during a pre-
determined period of time, knowing the length of the foam
supply pipeline we can determine the required diameter of
the pipeline. For example it takes 3 minutes to empty an
experimental tank filled with 50 kg composition from 14
bar to atmospheric pressure through a 2" pipeline of 4
meter length, the time of extinguishing is approximately
the same, and the foam blanket laid on the approximately
m2 surface of the liquid is 10 cm thick, resulting in
successful extinction of the fire.
A further advantage of the method and apparatus according
to the invention is that it supplies foam of uniform
quality. As the ratio of all the components of the foam is
adjusted when completing the composition in advance, the
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ratio of the volume of the bubbles and the quantity of the
foaming agent solution, that is, the spreading rate of the
foam is no longer dependent on external parameters. It
also implies the possibility that in course of its
operation an apparatus can continuously supply foam of
quality chosen as optimal for the given application.
It is an extra advantage of the foam expanding spreading
device of the invention that it is suitably situated
around the surface of the liquid, and in course of its
operation the foam emitted is ring-shaped, and this ring
is closing more and more while extinguishing the fire, and
finally covers the entire surface of the liquid. It is a
further extra advantage of the foam expanding spreading
device of the invention that it is suitable for letting
the foam either to the surface or under the surface of the
liquid.
The essence of the invention is now described in detail in
connection with preferable embodiments with reference to
the accompanying drawings in which:
Figure 1 is the sketch of the first embodiment of the
fire fighting foam producing and fire
extinguishing apparatus according to the
invention installed at a tank,
Figure 2 is the sketch of the second embodiment of the
apparatus according to the invention installed
at a tank,
Figure 3 is the sketch of a the third embodiment of the
apparatus according to the invention installed
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at a tank,
Figure 4 is a sketch of an advantageous embodiment of the
foam expanding spreading device constituting a
further object of the invention,
Figure 5 shows the varying dimension of the slit acting
as the discharge mouth of the foam expanding
spreading device shown in figure 4, via
"straightening" the device,
Figure 6 shows the foam expanding spreading device shown
in figure 4, in section along the A-A plane
indicated there,
Figure 7 shows another foam expanding spreading device
in similar section as indicated in figure 4,
Figure 8 is a lateral view and section of the foam
expanding spreading device shown in figure 4
installed in a tank,
Figure 9 is the sketch of a further advantageous
embodiment of the apparatus,
Figure l0 is the view of the second embodiment of the foam
expanding spreading device according to the
invention,
Figure 11 shows the section of the foam expanding
spreading device shown in figure 10,
Figure 12 is the view of the third embodiment of the foam
expanding spreading device according to the
invention.
The apparatus shown in figure 1 comprises a pressure
resistant tank (12), there is a pipe stub established on
the tank (12), (not indicated in the figure) so as to
introduce water, foaming agent and gaseous medium. A
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circulating pump can be connected to the appropriate pipe
stubs of the tank (12) in a detachable way, which can be
used for dispersing the components under pressure in the
tank (12).
The tank (12) is an installed tank, a pressure resistant
pipeline (40) is connected to its outlet, and a remote
controlled main valve (42) is inserted in the pipeline
(40). The valve (42) may be controlled by the sensor (49)
situated in the storage tank with the help of an
appropriate control unit (50). The end of the pipeline
(40) is protruding into the inner space of the storage
tank (1) containing the inflammable liquid, where it is
connected to the foam expanding spreading device (60)
situated inside the tank (1) above the surface of the
liquid along the nappe of the tank (1).
In course of the operation of the apparatus the compressed
foaming composition consisting of the foaming agent, water
and the propellant gas is prepared in the tank (12) or the
composition already prepared is filled in the tank (12).
If necessary the mixing of the composition can be promoted
using a mechanic mixer and the circulating pump. The
composition is stored in this status until being used.
When using the apparatus the foaming composition is let
into the foam expanding spreading device (60) through the
pipeline (40) by opening the valve (42), and the foaming
composition is expanding when leaving the device. The
expanded foaming composition is the ready-to-use fire
fighting foam itself, which is immediately let to the
place of application.
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The apparatus shown in figure 2 comprises a high-pressure
tank (15) containing the foam generating gas absorbed in
water, a foaming agent container (17) and a mixer (30).
Water and gaseous medium is let into the tank (15) mixed
or separately through an appropriate pipe stub, and mixing
can be promoted using a mechanic mixer and a circulating
pump. The outlet of the tank (15) is connected to one
inlet of the proportional mixer (30) with a stop-valve
(32) inserted, and the foaming agent container (17) is
connected to the other inlet of the mixer. The outlet of
the mixer (30) is connected to the foam expanding
spreading device (60) by the pressure resistant pipeline
(40) .
In course of the operation of the apparatus water with
propellant gas absorbed in it is completed in the tank
(15), and it is mixed with the foaming agent concentrate
with the help of the mixer (30) when the apparatus is
used.
This three-component composition containing the propellant
gas absorbed in it is let through the pipeline (40) and
the ready fire fighting foam is generated via its
expansion as described above.
The apparatus shown in figure 3 comprises a water tank
(20) connected to one inlet of the absorbing vessel (35)
with a booster pump (22) inserted. The outlet of a gas
container (19) is connected to the other inlet of the
absorbing vessel (35) with a pressure controller (37)
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inserted. The outlet of the absorbing vessel (35) is
connected to one of the inlets of a mixer (30), while the
outlet of a foaming agent container (17) is connected to
the other inlet of the mixer (30). The outlet of the mixer
(30) is connected to pressure resistant pipelines (40)
leading to storage tanks containing inflammable liquids,
where it is connected to foam expanding spreading device
s, of which the figure shows only the foam expanding
spreading device (60) situated in the tank (1). The
pipeline (40) branches and a disconnecting valve (45, 46)
is inserted in each branch of the pipeline.
In course of the operation of the apparatus water stored
in the tank (20) is enriched with propellant gas stored in
the container (19) in the absorbing vessel (35) and
foaming agent concentrate is mixed to this compound in the
mixer (30). The three-component composition discharged
from the mixer (30) is conveyed to the tank selected (e. g.
1) through the pipeline (40), through its branch
determined by the open disconnecting valve (45, 46) of the
pipeline (40), and the fire fighting foam is generated
there via its expansion as described below.
Figure 4 shows an advantageous embodiment of the foam
expanding spreading device (60) constituting a further
object of the invention. The foam expanding spreading
device (60) is a tubular equipment forming a kind of ring
adjusted to the shape of the storage tank to be protected,
fitting close to the inner surface of the sidewall of the
tank under the rim of it, and an admission opening (62) is
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formed on the branch neck (61) of the foam expanding
spreading device (60).
The discharge mouth on the tubular body (63) of the foam
expanding spreading device (60) is formed as a slit (65)
parallel to the axis of the tube in a way that the
distance between the edges of the slit (65) is growing
according to the distance from the admission opening (62).
The growing size of the slit is better seen in figure 5,
where a part of the foam expanding spreading device (60)
is shown "straightened" for better understanding. The
cross section of the admission opening (62) and the slit
(65) is conveniently the same.
Figure 6 shows the foam expanding spreading device (60)
in section along the A-A plane indicated in figure 4, the
arrow shows the direction of outflow of the foam. The foam
expanding spreading device producing a vertically
downwards directed foam-fall can be suitably used in
floating roof tanks, the foam flow is directed in the slit
between the floating roof and the sidewall of the tank. At
the solution shown in figure 7 the slit of the device is
situated so as to produce foam-fall directed partly
downwards and partly sideways, and it is particularly
advantageous to apply it at tanks with open liquid
surface.
In course of operation the foam flowing in through the
admission opening (62) is released through the slit (65).
The size of the slit (65) is growing according to the
distance from the admission opening (62), so the amount of
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foam released at sections of the slit farther away from
the admission opening (62) is the same as the amount of
foam released at sections closer to the admission opening
(62), as the pressure of the foam at sections of the slit
closer to the admission opening is higher. Accordingly, it
can be attained that the foam blanket released is of
uniform thickness all along the slit (65). If it is a
cylindrical tank, the surface of the liquid is covered in
a concentric manner, therefore the surface is entirely
covered within a short time.
Figure 8 shows the foam expanding spreading device (60)
installed in a tank (1), the dimensions in the figure are
not in proper proportion. The position of the admission
opening (62) can be clearly seen in the figure, and it is
also clearly seen that the slit (65) acting as a discharge
mouth is narrower at its end closer to the admission
opening (62), and it is wider at its other end farther
from the admission opening (62).
Figure 9 shows a further embodiment of the apparatus
according to the invention, where the water tank (20) is
connected to one inlet of the proportional mixer (30) with
a pump (22) inserted, and a foaming agent container (17)
is connected to the other inlet of the proportional mixer
(30). The outlet of the proportional mixer (30) is
connected to one inlet of an absorbing vessel (35), and a
foam generating gas container (19) is connected to the
other inlet of the absorbing vessel (35) with a pressure
controller (37) inserted. The outlet of the absorbing
vessel (35) is connected to the high-pressure pipeline
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(40) which branches at this example as well, and
disconnecting valves (45, 46) are inserted in each branch.
In course of the operation of the apparatus a solution is
made from the foaming agent using the proportional mixer
(30), and then the foam generating gas is absorbed in this
solution. The completed composition appears at the outlet
of the absorbing vessel (35) and gets into the pipeline
(40) in a ready-to-use form.
The foam expanding spreading device (60) shown in figure
comprises a high-pressure receiving chamber (67) and a
tubular distributing body (66). The chamber (67) is
connected to the tubular body (66) with hydraulically
balanced feeding, at this embodiment it is attained via
connecting members (71, 72 and 73) of choking effect
between the chamber (67) and the distributing body (66),
the chokes in the connecting members (71, 72 and 73) are
shown in the figure in broken-out section of the
connecting members (71, 72 and 73). A slit (68) acting as
a discharge mouth is made along the generating line of the
essentially tubular distributing body (66), while the
high-pressure receiving chamber (67) is connected to the
pipeline (40) at the admission opening (69) of the chamber
(67) .
Figure 11 shows the foam expanding spreading device (60)
shown in figure 10, in section along the A-A plane
indicated there. The high pressure receiving chamber (67)
and the distributing body (66) connected to it by the
connecting member (73) of choking effect is clearly seen
CA 02328972 2000-10-16
WO 99152599 PCT/HU99/00027
23
in the figure as well as the foam discharging slit (68) of
the distributing body (66) along its generating line.
In course of the operation of the foam expanding spreading
device (60) the pressure drops at the members of choking
effect, so it is the ready fire fighting foam that gets
into the inner space of the distributing body (66). The
longitudinal position of the distributing body (66) and
the slit (68) ensures that the fire fighting foam is let
to the place of application in the form of a blanket.
