CHARGING OF ACCUMULATORS FOR FIRE FIGHTING

CHARGEMENT D'ACCUMULATEURS POUR LA LUTTE CONTRE LES INCENDIES

English Abstract

A method for fighting fire, in which a drive unit
comprising a number of hydraulic accumulators is utilized
for delivering extinguishing liquid to a number of spray
heads or sprinklers. The procedure for avoiding a
premature waste of propellent gas is that, at a first stage,
the hydraulic accumulators (2, 3) are filled with gas, and
subsequently at a second stage, the accumulators are filled
with liquid, so that the liquid compresses the gas.

French Abstract

Procédé de lutte contre les incendies, selon lequel on utilise une unité de commande comportant un certain nombre d'accumulateurs hydrauliques et assurant l'alimentation en liquide extincteur d'un certain nombre de têtes de pulvérisation ou d'arrosage. Afin d'éviter toute fuite prématurée du gaz à propulseur, on effectue une première étape de remplissage des accumulateurs hydrauliques (2, 3) avec un gaz, puis une seconde étape de remplissage des accumulateurs avec un liquide, de sorte que le liquide comprime le gaz.

Claims

5
CLAIMS:
1. A method for fighting fire using a
source of fire-extinguishing liquid, a source of gas
at a first pressure, and interconnected hydraulic
accumulators including at least one gas container and
at least one liquid container, said method
comprising:
charging said hydraulic accumulators, said
charging comprising
interconnecting said hydraulic accumulators into
fluid communication with each other,
initially filling said hydraulic accumulators
with said gas at said first pressure from said source
of said gas, and
subsequently filling said liquid container with
said fire-extinguishing liquid from said source of
said fire-extinguishing liquid so that said fire-
extinguishing liquid drives said gas from said liquid
container into said gas container and compresses said
gas in said gas container to a desired initial
charging pressure; and
directing said fire-extinguishing liquid toward
the fire upon occurrence of the fire, said directing
comprising
pressing said fire-extinguishing liquid out of
said liquid container utilizing the pressure in said
gas container toward the fire.
2. A method according to claim 1, in
which the interconnected accumulators comprise a
number of liquid containers connected in parallel and
a number of propellent gas containers likewise
connected in parallel to the liquid containers,
whereby the propellent gas of the gas containers is

6
arranged to drive the liquid out of the liquid
containers, characterized in that, at the initial
filling stage, all liquid containers as well as all
propellent gas containers are filled with gas, and
subsequently, liquid is pumped into the liquid
containers so that the liquid drives the gas out of
the liquid containers and into the propellent gas
containers, whereby the pressure in the propellent
gas containers rises in proportion to the amount of
gas from the liquid containers to the gas containers.
3. A method according to claim 2,
characterized in that, at the first stage, all liquid
containers as well as all propellent gas containers
are filled with start air for diesel engines.
4. A method according to any one of
claims 1 to 3, characterized by floating a body in
the at least one liquid container for closing a
liquid outlet aperture of the at least one liquid
container and ending the directing of the fire-
extinguishing liquid toward the fire when the gas has
pressed the fire-extinguishing liquid out of the at
least one liquid container.
5. The method according to claim 4,
characterized in that the floating of the body
further comprises closing an outlet aperture for the
gas when the fire-extinguishing liquid drives the gas
from the at least one liquid container.

Description

CA 02175453 2004-12-13
1
Charging of accumulators for fire fighting.
The present invention relates to a method
and an installation for fighting fire, in which a
number of hydraulic accumulators are utilized for
delivering extinguishing liquid to a number of spray
heads or sprinklers.
The extinguishing liquid is usually driven
out of the hydraulic accumulators by means of
propellant gas, which is preferably nitrogen gas,
though air can be used as well. The propellant gas
shall generally be capable of having an initial
charging pressure of about 100 bar.
Necessary pressure gas containers or bottles
are mainly charged in advance somewhere else than
where they are used: Accordingly, there is always a
certain risk that the propellant gas is wasted e.g.
due to a leakage, before the fire-fighting
installation is actually needed. On land, this does
not generally imply any larger problem, while on
ships and objects comparable with them, which lack
necessary charging equipment, this risk is not
considered acceptable.
The object of the invention is to eliminate
this problem.
In one particular embodiment there is
provided a method for fighting fire using a source of
fire-extinguishing liquid, a source of gas at a first
pressure, and interconnected hydraulic accumulators
including at least one gas container and at least one
liquid container, said method comprising: charging
said hydraulic accumulators, said charging comprising
interconnecting said hydraulic accumulators into

CA 02175453 2004-12-13
la
fluid communication with each other, initially
filling said hydraulic accumulators with said gas at
said first pressure from said source of said gas, and
subsequently filling said liquid container with said
fire-extinguishing liquid from said source of said
fire-extinguishing liquid so that said fire-
extinguishing liquid drives said gas from said liquid
container into said gas container and compresses said
gas in said gas container to a desired initial
charging pressure; and directing said fire-
extinguishing liquid toward the fire upon occurrence
of the fire, said directing comprising pressing said
fire-extinguishing liquid out of said liquid
container utilizing the pressure in said gas
container toward the fire.
The procedure according to the invention is
mainly such that, at a first stage, the hydraulic
accumulators are filled with gas up to available
pressure, and subsequently at a second stage, the
accumulators are filled with liquid under a desired
initial charging pressure, so that the liquid
compresses the gas to the desired initial charging
pressure.
There are preferably a number of liquid
containers connected in parallel and a number of
propellent gas containers likewise connected in
parallel to the liquid containers, whereby the
propellent gas of the gas

WO 95113114 PCT/FI94100511
2
containers is arranged to drive the liquid out of the
liquid containers. At such an installation, the pre-
ferred procedure is that, at the first stage, all liquid
containers as well as all propellent gas containers are
i
filled with gas with available pressure, and subsequent-
ly, liquid is pumped into the liquid containers so that
the liquid drives the gas out of the liquid containers
and into the propellent gas containers, whereby the
pressure in the propellent gas containers rises in pro-
portion to the amount of gas from the liquid containers
to the gas containers.
Accordingly, if the total volume of the liquid
containers is for instance double as big as the volume
of the gas containers, it is possible to achieve in this
way a propellent gas pressure which is usable for fire-
fighting and three times as high as the gas pressure
available otherwise.
On ships, for instance, there is usually no
available gas having a pressure higher than about 35
bar, i.e. so-called start air for diesel engines, etc.
Thanks to the invention, this start air can charge the
drive unit of a fire-fighting installation to a pressure
Of about 100 bar without difficulty.
When air is used as propellent gas in a hydrau
lic accumulator unit for fire-fighting, it is usually
not desirable that the propellent air flows with the
extinguishing liquid to the seat of fire. This can be
avoided by providing the liquid containers with floating
bodies closing an outlet aperture for the liquid after
the containers have been emptied of liquid. For this
purpose, the floating bodies may be provided e.g. with
c~.nnt ral _p'I amantg~._,rthi rah pp~j,~trg~ j~tQ the. liquid Outlet
aperture when the container is empty and plug it up. The
floating bodies are preferably provided with correspond-
ing elements also on the gas side for securing that li-

WO 95/13114 PCTIFI94J00511
3
quid does not penetrate into the propellent gas contain-
ers while the liquid containers are filled.
' The invention will be described in the follow-
ing in greater detail with reference to a preferred
embodiment shown in the attached drawing.
In the drawing, a drive unit of an installation
for fighting fire is indicated by reference numeral 1.
The drive unit comprises four liquid containers 2 and
two propellent gas containers 3; the number of the con-
tainers 2 and 3 may vary as desired. In the drawing, the
drive unit is ready for use with the containers 2 en-
tirely filled with liquid and with the propellent gas
containers 3 charged to a pressure of about 100 bar. At
an activation, the gas containers 3 are connected, one
at a time or simultaneously, to a common feeder line 4,
whereby the gas presses the liquid out of the containers
2 via a common outlet line 5 and a feeder line 6 to a
current fire gone 7.
Floating bodies arranged in the containers 2
are indicated by 8, a gas feeder line from a separate
gas source, e.g. so-called start air for diesel engines
etc. on a ship, is indicated by 9 and a liquid pump of
about 100 bar is indicated by 10.
When necessary, if the propellent gas in the
containers 3 were wasted for some reason, the drive unit
may be charged to a state ready for use in the following
way by meansof start air from the line 9, which start
air can be supposed to have a pressure of about 35 bar.
At a first stage, all containers 2 and 3 are filled with
start air to a pressure of 35 bar, and subsequently, the
line 9 is closed. At a second stage, the containers 2
are filled with liguid bg.means of'.the...gumg_lLl.~.:tha.,li-~~.
' quid driving the initially fed gas out of the containers
2 into the containers 3. If each container 2 and 3, re-

W 0 95113114 PCTIFI94100511
4
spectively, has the same size, the containers 3 will be
charged to a pressure of about 100 bar.
At an activation of the installation, the '
floating bodies 8 sink downwards in the containers 2 as
soon as the liquid is driven out and reaches the bottom
of the respective container when it has been entirely
emptied. Since it is not usually desirable that the
propellent air flows with the extinguishing liquid to
the seat of fire, the floating bodies 8 are preferably
arranged to close the outlet aperture in the bottom of
the respective liquid container 2. For this purpose, the
floating bodies may be provided e.g. with conical ele-
ments penetrating into the liquid outlet aperture and
closing it when the container is empty. The floating
bodies are preferably provided with corresponding
elements also on the gas aide, for securing that liquid
is not penetrating into the propellent gas containers
while the liquid containers are filled. -TO construct
closing el8ments like that does not cause any difficulty
for one skilled in the art, and therefore, they are not
shown in detail in the drawing.
The number of liquid containers 2 and gas con-
tainers 3, as well as their mutual volumes, may vary
according to wishes. No separate gas containers are
needed, but the liquid containers may be closed at the
top, whereby it is naturally sufficient with a valve
effect downwards by the floating bodies 8. Between the
floating bodies 8 and the enclosing container wall,
there is a distinct space, preferably somewhat bigger
than the drawing gives impression of, due to which the
containers 2 can have a simple "rough" construction
without surface finish. Instead of so-called start air,
any other available gas source can be used.

Representative Drawing