Note: Descriptions are shown in the official language in which they were submitted.
21 94525
Patent
3031-21-00
WATER MIST FIRE SUPPRESSION DEVICE
Background of the Invention
This invention is directed to a novel and improved fire suppression device, and more
particularly to such a device which produces a water mist, and is self-contained. Still more
particularly, the fire suppression device may use an inert gas generator apparatus to facilitate the
5 formation and/or propulsion of a water mist.
Heretofore, water-based indoor fire suppression has generally been in the form of water
sprinkler systems which generally operate at ordinary building or municipal water pressure.- These
systems depend upon distributing a plurality of sprinkler heads around an area to be protected. Such
systems can be relatively complex and expensive, requiring piping interconnecting the sprinkler
10 heads and running to a suitable source of water, which is normally at the pressure provided in the
facility or building, or the municipal or other provider water pressure, that is, a relatively low
pressure. Such sprinkler systems when activated deliver large quantities of water at relatively low
pressures.
However, in many applications the distribution of a relatively large quantity of water in the
15 event of fire is considered undesirable. This may be due to the sensitivity of various types of
equipment to large quantities of water and/or the high probability of damage to such equipment in
response to a relatively large amount of water which would be applied by such a sprinkler system
in the event of fire. Such equipment may be found for example in computer rooms, turbine rooms,
bank vaults, and the like. Many industrial processes utilize equipment maintained at elevated
20 temperatures which could be damaged by rapid cooling due to application of a large quantity of
water.
`- 21 94525
Patent
303 1-2 1-00
In these latter types of applications, some non-water-based fire protection system is often
used, such as chemical-based fire extinguishers (often halon) which must be utilized by personnel
in the event of fire, or less commonly, some other distribution system in which a chemical fire
suppressant such as halon is applied. However, halon is no longer manufactured because of its high
5 ozone depletion potential.
A more recently emerging technology in fire protection is to use some form of water mist
system. Such systems use relatively small amounts of water in the form of a fine mist to extinguish
a fire, rather than the relatively large volume of water that an ordinary sprinkler system would
typically distribute or apply. A water mist operates to extinguish a fire by at least two d~lfferent
10 mech~nism~, namely, by extracting heat and by displacing oxygen. Such systems use relatively
small amounts of water in the form of a fine mist of very small (e.g., 50 microns) water droplets
to extinguish fires. As mentioned, such a water mist can extinguish a fire by using several different
mech~ni~m~. First, the rapid evaporation of the small water droplets extracts heat, and secondly,
oxygen is displaced due to the steam displacement of air, as water droplets are turned to steam.
15 Also, the amount of heat radiated from a flame to the unburned fuel is decreased.
These water mist systems are useful in areas where large volumes of water are not available,
or where large amounts of water could cause undesirable damage to equipment, for example,
computer rooms, bank vaults, turbine rooms etc., as mentioned above. Rather than using ordinary
nozzles and water at available pressure, such water mist systems generally utilize atomizing nozzles
20 which require a supply of water at relatively high pressure to produce the desired mist.
Such water mist systems therefore can be much like conventional sprinkler systems, in that
they can require extensive piping to provide water to the nozzles. In addition, these systems, unlike
conventional sprinkler systems, require pumps and high pressure connections, fittings, conduits and
21 94525
Patent
303 1-21-00
the like to maintain the required water pressure. Thus, such systems can be relatively complex and
be difficult and expensive to install, maintain and/or modify if desired. For example, the
modification of such a system to protect different equipment at different locations, to add locations,
or the like can be relatively complicated, expensive and time-consuming.
S Objects and Summary of the Invention
Accordingly, it is a general object of the invention to provide a novel and improved water
mist fire suppression device which does not require a separate remotely located high pressure water
source, or a system of intercannected piping, pumps or the like.
A related object is to provide a fire suppression device in accordance with the foregoing
10 object which may be relatively easily placed at, or moved to, a location a~ropliate for servicing
an area where fire protection is desired.
Yet another object is to provide a fire suppression device in accordance with the foregoing
object which is self-contained and can be provided in diverse sizes and configurations for use in
diverse applications.
Briefly, and in accordance with the foregoing objects, a fire suppression device comprises
an enclosure having opposite end walls and a side wall joining said end walls to define a hollow
chamber within said enclosure; an atomizing nozzle operatively coupled to a first of said end walls
and having an entrance portion adjacent said chamber and an exit portion in communication with the
atmosphere outside of said enclosure; a frangible barrier interposed between said nozzle entrance
20 and said chamber and responsive to a predetermined pressure for fracturing to permit communication
between said nozzle and said chamber; piston means located between said end walls and engaged
about an inner periphery of said side wall to divide said chamber into two parts comprising a first
section between said piston means and said first end wall to be filled with a quantity of water and
` 2194525
Patent
303 1-2 1 -00
a second section between said piston means and the other end wall, said first section comprising a
major fractional portion of the volume of said chamber; said piston being slidably moveable relative
to said side wall in the direction of said first end wall in response to a force exerted upon said piston
means for exerting pressure upon said quantity of water for initially fracturing said frangible barrier
5 and for thereafter delivering a water mist through said atomizing nozzle, and drive means for
exerting said force upon the piston means.
Brief Description of the Drawings
The features of the present invention which are believed to be novel are set forth with
particularity in the appended claims. The organization and manner of operation of the invention,
10 together with further objects and advantages thereof may best be understood by reference to the
following description, taken in connection with the accompanying drawings in which like reference
numerals identify like elements, and in which:
Fig. 1 is an elevation in section of a fire suppression device in accordance with the invention;
Fig. 2 is an elevation in section showing a second embodiment of a fire suppression device
15 in accordance with the invention;
Fig. 3 is an elevation in section showing an alternate form of an inert gas generator device
which may be utilized in the fire suppression device of the invention; and
Fig. 4 shows yet another form of inert gas generator device which may be utilized in the
invention.
20 Detailed Description of the IllustMted Embodiment
Referring now to the drawings and initially to Fig. 1, a fire suppression device in accordance
with the invention is decign~ed generally by the reference numeral 10. The device 10 includes an
enclosure 12 which has opposite end walls 14, 16 and a side wall 18 which joins the end walls
21 94525
Patent
3031 -21 -00
together to define a hollow chamber 20 within the enclosure. The end walls 14, 16 may be
generally circular in shape and the side wall 18 may be cylindrical and continuously formed with
and between the respective end walls 14, 16. However, other shapes, configurations and means of
joining the respective walls together to form the chamber 20 may be utilized without departing from
5 the invention.
Coupled to the end wall 14 is an atomizing nozzle 22 which has an entrance portion 24
adjacent the chamber 20 and an opposite or exit portion 25 which is in communication with the
atmosphere outside of the enclosure 12. A frangible barrier such as a burst foil 26 is interposed
between the nozzle entrance portion 24 and the chamber 20. Preferably, the burst foil overlies the
10 nozzle entrance portion 24 where it meets or intersects with the inner surface of the end wall 14.
This frangible barrier or burst foil 26 is responsive to a predetermined force or pressure exerted
thereupon for fracturing to thereby permit communication between the nozzle 22 and the chamber
20.
The chamber 20 is divided into a first or upper section 28 and a second or lower section 30
15 by a piston 32 which is located at a predetermined distance between the respective end walls 14, 16
and which is engaged about an inner periphery of the side wall 18. Preferably, this engagement is
such that water cannot pass around the edges of the piston 32. The piston 32 is slidably moveable
relative to the side wall 18 and is moveable generally in the direction toward the end wall 14 in
response to a pressure exerted upon the piston at its side opposite the wall 14. Thus, the piston 32
20 effectively divides the chamber into the first section 28 located between the piston 32 and the end
wall 14 and the second section 30 located between the piston 32 and the end wall 16. In its initial
condition and before any movement of the piston 32 relative to the respective end walls 14, 16, the
first section 28 of the chamber 20 comprises a major fractional part of the chamber, that is, it is
2~ 945~5
Patent
3031 -21 -00
much larger in volume than the second section 30, as defined by the piston 32. The first section 28
of the chamber 20 is filled with a quantity of water. Thus, when the piston 32 is forced upwardly
in the direction of end wall 14, the water in the first section 28 will exert a pressure upon the burst
foil 26, causing the burst foil to break and the water to flow through the atomizing nozzle 22 to
S create a water mist.
Referring now to the second section 30, a driver 40 is located or mounted in, or at least in
communication with, this second section 30 of the chamber 20. This driver produces the necessary
force or pressure to propel the piston toward the end wall 14.
Preferably, the driver 40 comprises a gas generator. This gas generator is operative for
10 generating a quantity of gas, and preferably of an inert gas, upon the occurrence of preselected
external stimuli, and for releasing this quantity of gas into the second section 30 so as to exert a
pressure upon the piston 32 to cause the release of a water mist at the atomizing nozzle 22 as just
described. This extemal stimulus may take the form of a suitable electrical signal produced by a
selected sensor, such as a heat sensor, smoke detector, or the like, which does not form a part of
15 the invention and is not illustrated herein. The form of sensor or transducer utilized to activate the
gas generator may take any suitable form without departing from the invention.
Fig. 2 illustrates a somewhat modified embodiment of a fire suppression device, design~t~d
generally by reference numeral 210. In many respects, the device 210 is similar to the device 10
illustrated and described above with reference to Fig. 1. Therefore, similar reference numerals will
20 be utilized to decign~te similar parts and components of the fire suppression device 210.
In similar fashion to the embodiment of Fig. 1, the fire suppression device 210 has an
enclosure 212 formed of a first wall 214, a second wall 216 and a side wall 218 which define a
chamber 220. An atomizing nozzle 222 has an inlet 224 and an outlet 225. Departing from the
` 21 94525
Patent
3031-21 -00
embodiment of Fig. 1, the atomizing nozzle 222 is here illustrated as an air assist atomizing nozzle.
The chamber 220 is split into a first section 228 and a second section 230 by a slidably mounted
piston 232.
Departing from the embodiment of Fig. 1, the air assist atomizing nozzle utilizes an elongate
5 tubular conduit 250 which extends between the nozzle 222 at a first end 251 and the second section
230 of the chamber at a second end 253 for delivering a portion of a gas generated by a gas
generator 240 to the nozzle 222 for propelling water therethrough. In this regard, the nozzle 222
includes a plurality of diagona~ly inclined passageways or venturis 252, 254, each of which has one
end forming the nozzle inlet 224 adjacent to the first section 228 of the chamber and an opposite
10 end intersecting the intenor of the tubular conduit 250, just below the outlet 225 which generally
coincides with the end 251 of the tubular conduit 250.
A frangible barrier or burst foil 226 which operates in the same fashion as burst foil 26 is
interposed between the inlets 224 to the venturis 252, 254 and the chamber portion 228. In this
embodiment, the burst foil 226 is a generally flat, annular member which surrounds the tubular
15 conduit 250, so as to initially overlie the entrance 224 of each of the plurality of venturis 252, 254.
It will be understood that while two such venturis have been illustrated herein, only a single such
venturi, or more than two such venturis, may be provided without departing from the invention.
Similarly, the burst foil 226 may be provided in a different configuration or as a plurality of
individual members, one for each inlet 224 without departing from the invention. In the illustrated
20 embodiment, it will be noted that the internal diameter of the tubular conduit 250 is narrowed
somewhat at its upper portion, just prior to the point of intersection with the passageways 252,254.
Also, to accommodate the tubular conduit 250, the piston 232 is provided with a central
through opening which is arranged with a bent back edge, similar to its bent back outer edges, as
21 94525
Patent
3031-21-00
illustrated also in Fig. 1. These bent back edges enable the piston to slidably engage and maintain
a water seal against both the outer wall of the tubular conduit 250 and the inner surface of the side
wall 218. This facilitates the sliding motion of the piston 232 in the direction of the first wall 214
in response to the pressure exerted thereupon by the release of gas from the gas generator 240.
Turning now to the gas generator 240, as mentioned above, it preferably comprises an
inflator device of the type generally utilized for an inflatable vehicle occupant restraint device or air
bag. Generally speaking, this inflator 240 includes a housing 242 which has a generally circular
bottom wall 244 and a generally circular top wall 246 and a generally cylindrical outer peripheral
wall 248 extending between and operatively joining the top and bottom walls 246 and 244 to form
10 a housing. Spaced radially inwardly of the outer peripheral wall 248 is a generally cylindrical
internal wall 256 which extends between and joins the top wall 246 and bottom wall 244. Typically,
the top wall 246, outer wall 248 and internal wall 256 are formed as a unit and are joined to the
bottom wall 244 by a process such as inertia welding. In this regard, it will be seen that the bottom
wall 244 has a pair of generally annular, short concentric upwardly extending surfaces or rings
15 which respectively align with and engage the outer wall 248 and internal wall 256.
The walls 248 and 256 define a pair of chambers, including a cylindrical ignition chamber
258 inside of the wall 256, with the chamber 258 being partially filled with an ignition material 260,
and also accommodating an initiator or squib 262. Radially surrounding the wall 256 and inside of
the outer wall 248 is a generally annular generator chamber 264 which houses a quantity of a
20 pyrotechnic gas generant material 268. This material may have various compositions such as an
azide, and may be in many forms, a tablet form being here illustrated for purposes of description.
The internal wall 256 includes a plurality of ignition ports 270 which extend between the
ignition and generator chambers 258, 264 to permit the hot gases from the ignition material 260 to
- 21 94525
Patent
3031-21-00
flow into the generator chamber 264 and cause the generant material 268 to generate a quantity of
gas. Similarly, the outer wall 248 is provided with a plurality of gas exit ports 272 through which
the generated gas exits the gas generator 240 into the second section 230 to thereby exert a pressure
upon the piston and urge the piston in the direction of the first wall 214.
Intermediate the gas generant material 268 and the inner surface of the outer wall 248 in
which the exit ports 272 are located, there is interposed a filter structure design~ted generally by the
reference numeral 274 for filtering and cooling the generated gas prior to its exit through the ports
272. The filter is of a genera~ly cylindrical or tubular form.
Without departing from the invention, gas generator structures of different configuration may
be ~ltili7ed. For examplç, a structure in which the exit ports 272 are provided in the top wall 246,
and wherein the filter structure or assembly is a generally annular disc-like member interposed
between the gas generant material 268 and the inner surface of top wall 246 may be utilized.
In operation, the initiator 262 is responsive to an externally generated electrical signal for
producing a burst or quantity of energy which will cause the ignition material 260 to rapidly ignite.
This will cause hot gases to flow through the ports 270 into the generator chamber 264, thereby
causing the generant material 268 to rapidly generate a quantity of gas, preferably an inert gas,
which will exit the ports 272 into the second section 230 of chamber 220, for driving the piston 232
as previously described.
It will be seen that the gas generator 240 is coupled with the enclosure 212 by means of an
20 outwardly projecting mounting flange 280, which extends generally radially outwardly of the gas
generator 240. In the illustrated embodiment, this mounting flange 280 is formed as an extension
of the bottom wall 244 of the gas generator 240 and has a number of through apertures for accepting
suitable fasteners 282 to couple the same to an external surface of the enclosure 212 on its second
- 2 1 94525
\
Patent
3031-21 -00
wall 216. In this regard, the second wall 216 may also be provided with aligned openings which
may be tapped to mate with fasteners 282 to accomplish this interconnection. Cooperatively, the
second wall 216 may be provided with an enlarged, generally centered opening 284 to receive the
outer wall 248 of the gas generator 240 therethrough such that the exit ports 272 communicate with
5 the second section 230 of the chamber 220, and such that the mounting flange 280 abuts and aligns
with an outer surface of the second wall 216 of the enclosure 212. Suitable sealing means such as
an annular O-ring 286 may be interposed also between the bottom wall 244 and second wall 216.
The bottom wall 244 will be seen to be formed with a short, generally cylindrical upwardly
extending skirt portion which terminates in the radially outwardly extending flange portion which
10 also provides a surface f!or accommodating the O-ring 286.
Referring now to the rem~ining drawings, two further forms of gas generators might be used
in place of the gas generator 240 described above without departing from the invention. Indeed, any
suitable form of gas generator or gas generator-like device which produces a quantity of gas or other
fluid under pressure for driving the piston 232 in the fashion described above might be utilized
15 without departing from the invention.
Fig. 3 illustrates a gas generator ignition assembly using a projectile of the type which is
illustrated and described in U.S. Patent No. 5,230,531 which is incorporated herein by reference
to the extent relevant. Thus, the structure and operation of the gas generator of Fig. 3 will not be
described in detail herein.
Briefly, however, the gas generator of Fig. 3, which is design~ted generally by reference
numeral 300, utilizes a container 310 in the form of a tubular bottle, cylinder or tank of the type
often utilized for storing pressurized gas. An end part of the container 310 is provided with a fitting
320 in which there are formed a plurality of gas exit ports 330. Suitable means may be utilized to
21 94525
Patent
3031-21-00
assure communication of these gas exit ports 330 with the second section 30 or second section 230
of the chamber 20 or 220 of the embodiments of either Fig. 1 or Fig. 2, as described hereinabove.
Referring to the inflator device 300, a quantity of pressurized gas is contained within the
container 310. An isolating disc 332 prevents the gas in the container 310 from reaching the exit
5 ports 330. In operation, a suitable detector or sensor device (not shown) will sense a condition
requiring operation of the fire suppression device and transmit a co"esponding signal to an
activation assembly 334. The activation assembly 334 includes an electro-explosive device having
a projectile 336. When activated by the appropliate signal, the electro-explosive device propels
projectile 336 toward the disc 332 to penetrate and separate the disc to allow gas to begin flowing
10 from the container 310 through the exit ports 330.
A gas generator assembly 340 utilizing a gas generant material 342, for example, similar to
the generant material 268 described above with reference to Fig. 2 is also housed generally co-
axially within the container 310. This gas generator assembly is provided to augment the flow of
gas from the container 310 through the exit ports 330. Further, the heat produced by the
15 combustion of the generant material will serve to raise the temperature, and therefore the pressure,
of the stored gas. The gas generator assembly is activated by a change in pressure which is sensed
by a bi-stable diaphragm 343 which is mounted in a reference chamber 344 containing a quantity
of gas at a predetermined pressure.
As gas flows from the container 310, the pressure experienced on the diaphragm at its surface
20 opposite the reference chamber 344 decreases, since this surface is in contact, via ports 346, with
the exiting gas in container 310. Consequently, a central portion of the diaphragm is propelled
generally in the direction of the gas generator assembly 340, also propelling and impacting a pin 348
in this direction. The pin 348 is impacted into engagement with a percussion primer 350 to ignite
21 94525
Patent
3031-21 -00
the generant material 342. The gases generated by the generant material 342 then exit its gas
generator assembly 340 through a series of assembly exit ports 352 formed in end surfaces thereof,
to augment the flow of gas from the container 310.
Referring now to Fig. 4, yet another type of gas generator is illustrated and design~ted
5 generally by reference numeral 400. Similar to the gas generator 300 of Fig. 3, the gas generator
400 includes a tubular container 410 which contains a quantity of pressurized gas, and preferably
an inert gas. The container 410 has an exit fitting 412 which has a plurality of internal ports 414
which communicate with the-interior of the container and a plurality of external ports 416 which
communicate with the external atmosphere.
As with the inflator of Fig. 3, any suitable means may be utilized to form an operative
interconnection for the gases flowing from the ports 416 into the second section 30 or second section
230 of the fire suppression device in order to drive the piston 32 or 232. Also in similar fashion
to the embodiment of Fig. 3, a frangible barrier 420 is interposed between the internal ports 414 and
external ports 416. This barrier 420 is responsive to a predetermined increase in pressure exerted
15 thereupon from within the container 410 for bursting to allow communication between the respective
ports 414, 416 and consequent gas flow outwardly of ports 416.
A col-,pa lment 424 is also defined within the container 410 by a partial wall structure 426
having a central opening 428 which is closed by a frangible barrier 430. The compartment 424
contains a quantity of one or more fluid fuels and one or more oxidants to form a volatile mixture.
20 Upon occurrence of a suitable signal from a suitable external sensor or other transducer (not shown),
a suitable activating electrical signal is fed to an initiator 432 which extends into the compartment
424. This initiator 432 may be of similar form to the initiator 262 illustrated and described above
with reference to Fig. 2. The initiator 432 when thus activated produces a burst of energy which
2~ 94525
Patent
3031-21-00
will ignite the volatile mixture in the compartment 424, in turn bursting the barrier 430 and expelling
additional pressurized gas into a gas storage portion 415, defined within container 410, and outside
of wall structure 426. The consequent rise in pressure will in turn cause fracturing of the barrier
420 to cause the pressurized gas, augmented by gas flow from the volatile mixture in chamber 424,
5 to flow outwardly through the external ports 416.
A suitable fluid fueled gas generator which might be utilized as the gas generator 400 is more
fully illustrated and described in the co-pending U.S. patent application Serial No. 08/252,036 filed
May 31, 1994 under the assrgnee's docket number 2525-21-00 which is incorporated herein by
reference to the extent it describes such a device.
What has been illLlstrated and described herein is a novel and improved, self-contained water
mist fire suppression device. Preferably, the device is driven by a gas generator or gas generator-
type device, although other means of driving or powering the fire suppression device might be
utilized within the scope of the invention as defined by the claims herein.
While particular embodiments of the invention have been shown and described in detail, it
15 will be obvious to those skilled in the art that changes and modifications of the present invention,
in its various aspects, may be made without departing from the invention in its broader aspect, some
of which changes and modifications being matters of routine engineering or design, and others being
a~arent only after study. As such, the scope of the invention should not be limited by the particular
embodiments and specific constructions described herein but should be defined by the appended
20 claims and equivalents thereof. Accordingly, the aim in the appended claims is to cover all such
changes and modifications as fall within the true spirit and scope of the invention.
