GB2320189A - Portable water mist fire-extinguishing apparatus - Google Patents

Abstract

spraying apparatus comprises a nozzle 12, hand-held means 11 for controlling the spray of fluid from the nozzle, storage means 1 for the fluid, and a hose 10 for delivery of the fluid from the storage means 1 to the hand-held means 11. The storage container 1 may be carried as a back-pack 8 or mounted on wheels 7 for easy transportation. The nozzle may be an atomizing jet to produce a fine mist to smother and cool the fire. The hand-held means may be a pistol-like device.

Description

The present invention relates to a fire fighting apparatus and method relying upon a non-flammable liquid such as Water, for extinguishing a fire including Class A and B and C fires.

In fighting fires it is known that there are three major contributing factors to the continuation of the fire. These factors are heat, oxygen and fuel. This relationship is shown pictorially in Figure 1. When extinguishing fires, fire fighters act to remove at least one of the three elements necessary for combustion. Typically, fire fighters use either Water; water with additives such as a film forming foam; or gases such as Halon, Bromo-chloro-fluorocarbons (BCF),or CO2 as several examples. Water acts by removing the heat from the fuel, whilst gases such as Carbon dioxide works by displacing the oxygen.

Another aspect of combustion is a chain flame reaction indicated by a circle which contains the triangle, as shown in Figure 1. The chain flame reaction relies upon free radicals which are created in the combustion process and are essential for its continuation. Halon, for example, operates by attaching itself to the free radicals and thus preventing further combustion.

The main disadvantage of using plain water is that often considerable amounts of water are required to extinguish a fire which leads to considerabie damage by the water. Also, in some instances suitable quantities of water required to extinguish a fire is not available. Gases such as Carbon dioxide and Halon are often used to extinguish fires, both have the disadvantage that the area in which they are to be used must be evacuated since it will become impossible to breathe. For this reason, fire fighters using gaseous extinguishing agents must use breathing apparatus.

Also, Halon has a further disadvantage in that it is highly toxic and very damaging to the environment. For those reasons, the use of Halon in extinguishing fires has been banned under the Montreal Protocol and its manufacture and use is no longer possible.

Another disadvantage of rising CO2 and Halon gases to extinguish fires particularly in large spaces such as buildings is the large volumes of gas required. Typically, it is required to fill a space such as a building where a fire is situated with CO2 to a saturation level of 87%. Typically, this means the use of many CO2 cylinders connected via a manifold pipework to distribution lines containing nozzles.

Typically, when Halon is used to extinguish a fire in a space it is required to fill the room with between 5% to 7% saturation level. Typically, this means the use of many Halon cylinders connected via a manifold pipework to distribution lines containing nozzles.

A further disadvantage of using gaseous fire extinguishing mediums such as CO2 and Halon is their relatively high costs. Typically, Halon is purchased for US 100 to US 120 Dollars per kilogram based on current prices.

A further disadvantage of using gaseous mediums to extinguish fires in spaces is that it is required to close or shut all doors and ventilation points. Excessive ventilation in a space will not yield satisfactory results when attempting to extinguish a fire using gases such as CO2 or Halon because the gases will escape.

A further disadvantage of using gaseous mediums such as CO2 and Halon to extinguish a fire is that gases offer very poor cooling qualities on hot objects. Typically, for example, if a hydrocarbon fuel sprays directly onto a hot engine exhaust manifold from a ruptured fuel line, it will cause re-ignition. This will lead to a phenomena known as flashover.

The present invention overcomes the above disadvantages by using a non-flammable liquid to reduce the heat of the vapour around the fuel, reduce the heat of the fuel, displace the oxygen, and interrupt the flame chain reaction. That is, the liquid attacks all parts of the combustion process except for removing the fuel. The invention is based upon the generation of a relatively fine mist of non-flammable liquid, such as water, which displaces the oxygen, and upon heating evaporates and expands to further displace the oxygen. Upon expansion the water absorbs heat from the vapour around the fuel and from the fuel. Also, the mist interrupts the flame chain reaction. Consequently, the mist has a smothering effect and a cooling effect upon the fire. For these reasons, the mist has the surprising result that water can safely be used to extinguish A and B and C Class fires. Typically, C Class fires are electrical fires. The mist is not a conventional water on flame scenario.

Typically, water mist fire extinguishing systems are used to extinguish fires by propelling a fine water mist into a fire incident. Typically, the non-flammable liquid is pumped under elevated pressure through a network of pipe or pipes and then through a nozzle or a number of nozzles.

When expelled under pressure through the nozzle(s), the non-flammable liquid, in this case water, atomises into finer droplets. The incident area becomes saturated with water mist thereby cooling the fire incident area and extinguishing the fire.

Typically, some water mist systems utilise a network of distribution lines. If the space to be protected is relatively large, a distribution network of piping with a plurality of nozzles is required. Typically, the network of distribution pipes is a fixed installation, meaning it is not portable.

The present invention concerns an improved portable water mist fire extinguishing apparatus called "Porta-mist". Typically, the water mist apparatus is portable meaning that it can easily be moved and transported by firefighters from scene to scene. Firemen can wear the apparatus on their back similar to a breathing apparatus set or can carry or wheel the unit to a fire incident scene, or affix it to a motor cycle to combat fires.

In accordance with one aspect of the present invention there is provided a fire extinguishing apparatus called Mistex Porta-mist which comprises a Mistex Water Mist Nozzle for spraying water mist droplets to cause fire extinguishment; a hand held device called a lance which has a pistol-type grip on/off valve mechanism to control water flow and onto which the Mistex nozzle is attached; a delivery hose connecting the lance to a self contained water storage cylinder or cylinders which contain water under pressure similar to a portable hand held fire extinguisher; a number of fittings to attach the delivery hose to the cylinder or cylinders; a pressure gauge; a dip tube; valves to turn on or shut off the water discharge; a schrader valve for pressurisation means; all mounted onto a cradle which can be worn on the back of a fireman similar to a breathing apparatus set; or devised into a wheeled unit, or be fitted to a motor cycle.

The present invention is an improvement to traditional portable hand held fire fighting apparatuses, such as hand held fire extinguishers using plain water or water mixed with foam which is expelled through a foam nozzle, or gaseous portable fire extinguishers which use gas for fire extinguishment.

Typically, the improvement under the present invention incorporates the ability of firemen to wear the fire fighting apparatus called Porta-mist on their back similar to a breathing apparatus enabling greater versatility to climb ladders or mount obstructions when combating fires, and also freeing their hands to carry civilians to rescue or perform other duties. The present invention uses water in the form of a fine mist. This means water has a greater surface area to volume ratio thereby increasing its thermodynamic potential far greater than is the case with traditional portable water based fire extinguishers. Having a greater thermodynamic potential means that water is utilised more effectively and more efficiently when combating fires. Smaller water droplets transform into superheated steam much more quickly than larger droplets thereby increasing the latent heat absorption properties of water. This is the principal of water mist technology when applied to fire fighting conditions.

Typically, the present invention means that less water is required to accomplish fire extinction because the thermodynamic potential of water has been improved. Less water means less secondary water damage to buildings or other property. Using water in the form of a fine mist means that the smothering effect on a fire is much greater and when fine water droplets rapidly transform into steam, it displaces the oxygen around the fire plume thereby aiding in extinguishment.

Water mist systems have the surprising effect of achieving rapid fire extinguishment and cooling of the fire plume simultaneously. Water mist cools down hot surfaces more quickly than gases do, or when water is deployed through other means such as sprinkler systems, or traditional portable hand held fire extinguishers.

Typically, the operating pressure for Portamist can range from 7 Bar pressure upto 150 Bar pressure. All pressures within this range are possible depending on the degree of water atomisation required and horizontal discharge distance sought. Generally, Porta-mist is a moderate pressure system meaning typical operating pressures upto 20 Bar.

Excellent discharge qualities, spray flux densities and spray momentum were achieved in tests at operating pressures of 20 Bar. Live fire tests revealed remarkable benefits of Porta-mist over traditional portable hand held fire fighting apparatuses such as water and foam extinguishers.

The inventors manufacture two Models of Mistex water mist nozzles; a "S" Series multiple orifice type having a narrower spray pattern of 700 spray angle; or a "Y" Series multiple orifice type with a wider spray pattern of 1300 angle. Porta-mist incorporates the use of both of these nozzle types and spray angles, and other angles are also possible. The Mistex nozzle with a 700 spray angle is shown in Figure 2 and the Mistex nozzle having a 1300 spray angle is portrayed in Figure 3.

The Mistex 'S" series 700 spray angle nozzle has a narrower spray pattern meaning that the water mist column is not very dispersed. This means that the Mistex "S" series nozzle will have a greater horizontal spray trajectory, typically upto 20 metres distance from the nozzle at 20 Bar pressure. The Mistex "Y" series nozzle on the other hand, has a 1300 spray pattern which is wider meaning that the water mist column is more dispersed. This means that the Mistex "Y" series nozzle will have a lesser horizontal spray trajectory, typically upto 10 or 12 metres distance from the nozzle. Both nozzles can be used on Porta-mist and both nozzles are known to yield remarkable fire extinguishing characteristics. Use of the wider "Y" series nozzle or the 'S" series nozzle is a matter of choice.

Typically, the Mistex "S" series nozzle has a narrower 700 spray angle because the nozzle housing assembly is machined with a flat base, the angle of spray being influenced by the machined swirl chambers and swirl jets. When water enters the Mistex nozzle under elevated pressure, it enters the swirl chamber through the machined swirl jet hole and swirl jet passages. The swirl jet passages are machined at an angle which causes the water to rotate when entering the internal swirl chamber. Upon entering the swirl chamber, the pitch of the swirl chamber causes the water which is under pressure to gain velocity and swirl faster until it exits the swirl chamber through the nozzle orifices. The combined elevated pressure and swirling action causes the water to exit the nozzle in the form of a fine mist. The elongate round hole drilled longitudinally through the centre of the swirl jets give a "rifling" effect to the water entering the swirl chamber, and causing a greater discharge distance via the nozzle orifices.

Typically, the Mistex "Y" series nozzle has a wider 1300 spray angle because the nozzle housing assembly is machined with angled sides. The swirl chambers and swirl jets are identical to those described above for the Mistex "S" series nozzle. The principle hydraulics are identical, except for the angles on the nozzle housing assembly. The angles on the nozzle housing assembly combined with the dispersion of water mist created by the swirling action by the swirl jets and profile within the swirl chambers yields a wider spray angle coverage of 1300.

Typically, the Mistex nozzle is affixed to a threaded end of the hand held lance which has a valve mechanism to control hydraulic flow, for example, to squeeze the pistol-type grip lever will release the nonflammable liquid under elevated pressure to discharge through the nozzle, or when releasing the pistol-type lever grip, will shut off hydraulic flow through the nozzle. An example of the hand held lance with valve mechanism is portrayed in Figure 4. Alternatively, the valve mechanism can take on other forms, for example, a standard ball valve whereby the operator will turn the lever to "on" position to cause hydraulic flow, or turn the valve lever to the "off" position to stem hydraulic flow. Porta-mist can use any one of the above valve mechanisms for system activation.

The hand held lance will be connected to a high pressure delivery hose which will be connected to the water storage cylinder or cylinders which are either back mounted; hand held; wheel mounted; or motor cycle mounted units. The length of delivery hose will depend on the type of unit manufactured, although typically for back mounted units will be no longer than 1.0 metre, and for wheel mounted units can be anywhere upto 6 metres in length, or longer. Delivery hoses are high pressure rated with stainless steel braiding, or are typical hydraulic rubber type hoses which are used for hydraulically operated machinery where high pressures are frequently encountered.

The hand held lance will be capable of accommodating all working pressures cited earlier, that is, from 7 Bar and upto 150 Bar pressure.

Typically, the hand held lance will be pressure rated to 200 Bar for safety reasons.

Typically, the Porta-mist Water Mist Fire Extinguishing apparatus works upon the following principles: The Porta-mist fire extinguishing apparatus comprises of a cylinder or cylinders containing a non-flammable liquid under elevated pressure, having a high pressure hydraulic delivery hose installed to a hand held lance with valve mechanism, onto which is installed a Mistex water mist nozzle for water mist generation. Upon activation fine water mist droplets are propelled into a fire incident area causing extinguishment. Porta-mist is engineered and designed to deliver the correct amount of water under specified pressure and according to water flow rates to yield an optimal flux density and spray momentum to achieve fire extinguishment.

Typically, upon a fire incident occurring, the fire fighter will engage a fire using Porta-mist and will direct the fine water mist into the seat of the fire and will spray the mist in a side-to-side fashion until the fire is extinguished. Any number of Porta-mist units can be used simultaneously to combat a fire incident, depending on how large the fire is.

Typically, the non-flammable liquid is water, and fresh or salt water can be used, including water with additives, such as a fire fighting foam or a wetting agent. A suitable fire fighting foam is an aqueous film-forming type. Porta-mist can be used to extinguish hydrocarbon fuel fires, including and not limiting to the generality hereof, polar solvent fires, fibrous fires such as wood, paper, clothing and other textiles, rubber and plastics fires, including electrically induced fires.

The Porta-mist fire extinguishing apparatus has a droplet size in the range between 40pm to 100cm which enhances its trajectory into the fire plume and into the seat of the fire, thereby increasing the latent heat absorption properties of water. The mist droplet sizes can have diameters as small as one (1) micron and as large as 1,000 microns. The present invention embodies all droplet sizes between these two ranges.

The present invention will now be described with particular reference to use with non-flammable liquid being water, although, it is to be understood that it is of general applicability.

An exemplary embodiment of the present invention will now be described with particular reference to the accompanying drawings, in which: Figure 1 is a drawing depicting the combustion triangle and flow chain reaction circle.

Figure 2 is a typical schematic drawing of a Mistex deluge nozzle Model "S" Series used in fire fighting having a typical 700 spray angle revealing important components; Figure 3 is a typical schematic drawing of a Mistex deluge nozzle Model "Y" Series used in fire fighting having a wider 1300 angle spray revealing important components; Figure 4 is a typical schematic drawing of a hand held lance fire fighting apparatus having a Mistex Model "Y" Series nozzle attached thereto revealing important components; Figure 5 is a typical schematic drawing of a Porta-mist hand held lance fire fighting apparatus having a Mistex Model "Y" Series nozzle attached revealing important components; Figure 6 is a typical drawing of a Porta-mist back-pack mounted fire fighting apparatus comprising one water storage cylinder revealing important components; Figure 7 is a typical drawing of a Mistex Porta-Mist wheel mounted fire fighting apparatus showing important components.

In Figure 2 there is shown an exploded view of a Mistex "S" Series multiple orifice nozzle that can typically be affixed to a pipe 1, the nozzle having a flange plate assembly 2, which affixes to a nozzle housing assembly 3, with in-built swirl chambers 4, the swirl chambers containing swirl jets 5, with machined water swirling grooves 6, to cause the water to enter and swirl within the chamber for atomisation, and a longitudinally drilled hole 7, in the centre of the swirl jet to cause an increase in water velocity through the swirl chamber to yield greater water mist trajectory.

In Figure 3 there is shown an exploded view of a Mistex "Y" Series multiple orifice nozzle 1, the nozzle having a flange plate assembly 2, which affixes to a nozzle housing assembly 3, having in-built swirl chambers 4, into which screw in the swirl jets 5, with machined grooves 6, for water to enter and swirl within the chamber, and longitudinally drilled elongate hole 7, for causing water to enter the swirl chamber under greater velocity, and multiple orifices 8, from which water exits the nozzle in the form of a fine mist.

In Figure 4 there is shown a typical portable mist hand held lance called "Port-Mist" 1, with a threaded end 2 for attaching a hose line, a Mistex water mist "Y" Series nozzle 3, with multiple orifices 4 from where water mist exits under elevated pressure, and a hand trigger mechanism 5 for controlling water flow through the nozzle. Figure 4 is a typical arrangement of the present invention and portable mist lances may have other design features as shown in Figure 5. All variations in designs are included under the present embodiment.

In Figure 5 there is shown a typical portable water mist lance called Porta Mist 1, with Mistex "Y" Series water mist nozzle attached 2, showing multiple orifices 3, the lance having an inbuilt mechanism for regulating water flow 4, and a connection port 5, where a water hose can be attached for operation of the lance. This design is in contrast to the design shown in the previous Figure 4 whereby the water delivery hose is connected at the base of the pistol grip and the Porta-Mist lance is shorter.

In Figure 6 there is typically shown a Porta-Mist fire extinguishing apparatus with pressurised water storage cylinder 1, having a valve mechanism 2, with manually operated valve control knob 3, pressure gauge 4, having a threaded nipple 5, to which attaches the hose coupling 6, having a water delivery hose 7, all mounted onto a back-pack frame assembly 8, the cylinder being held firmly in place with fastening straps 9, the back-pack assembly accommodating the Porta-Mist unit being capable of being strapped to a fireman by fastening straps 10.

In Figure 7 there is shown a typical Mistex Porta-Mist wheel mounted fire fighting apparatus having a water storage pressurised cylinder 1, with filling cap 2, having an activation head 3, affixed to the actuator head is a dip tube 4, the cylinder having a pressure gauge 5, with a pressurisation means 6, the cylinder being mounted onto a set of wheels 7, onto which is supported a handle for towing or manoeuvring unit 8, a hose reel 9, the cylinder having a delivery hose attached 10, onto which is affixed a Mistex hand held lance 11, containing a Mistex nozzle 12 for water mist spraying.

Porta-Mist back-pack units can be manufactured with either a single stored pressure cylinder or a twin storage pressure cylinder and the present invention embodies both types of fire extinguishing apparatus. Also, the water storage cylinders are manufactured in various sizes and capacities from 3 litres each cylinder and upto 30 litres per any one cylinder for single cylinder units, or where twin cylinder units are used, cylinder sizes can be from 3 litres each to 15 litres each. Larger sized cylinders will mean they are too heavy to wear by firemen. Larger units exceeding 30 litres capacity are manufactured in wheel mounted units. The present invention also embodies these wheel mounted units, having capacities from 40 litres upto 120 litres or greater.

It is to be noted that in Figure 6, a threaded 10 hose coupling and male nipple is used to pictorially display the hose attachment, however, various means can be used including direct hose coupling via a hose clamp or connection via a "quick-release" pneumatic (or air-line type) coupling for easy connection and disconnection.

Porta-Mist water storage cylinders can either be provided with internal dip tubes where the cylinders are used in their upright position, or can have no dip tube where the units are used in an upside position. Upside down position means that the cylinders are arranged with the valve assembly being downwards. By not having a dip tube, the weight and cost is kept to a minimum. Water storage cylinders can be manufactured from alloys or from reinforced glass fibre or plastic compositions. The present invention embraces all types of material compositions. Likewise, for the frame assembly, various compositions may be used including light weight alloys such as aluminium, or reinforced glass fibre or plastics. It is important to keep the weight down for the user of these systems.

Another important aspect of the present fire fighting apparatus is its suitability and adaptability to be fitted to motor cycles for fire fighting purposes. This concept is also hereby claimed under the present invention.

Porta-Mist systems comprising of one or more self contained water storage pressurised cylinders with a flexible delivery hose and Mistex hand held lance can be fitted to motor cycles for combating fires. A single pack or twin pack Porta-Mist unit can be fitted to a motor cycle in the carrying compartment(s). The motor cycle can be mobilised in busy suburban streets or inhospitable terrain where larger fire fighting vehicles cannot easily navigate to reach a fire incident area.

Motor cycles can navigate busy streets through peak hour traffic much easier than larger fire tenders, and can therefore attend to or reach a fire incident area very quickly. Mobility means versatility, and motor cycles can easily navigate inhospitable terrain through valleys and hills to reach a brush fire or remote location for rescue purposes.

Typically, Mistex Water Mist nozzles are manufactured in different sizes and dimensions, having various K-factors and resultant flux densities.

Water flows for different nozzles vary according to the operating pressures, the number of orifices per nozzle, the size of orifices, the size of nozzles and other operating parameters. Fiow rates can be as low as 3 litres per minute or as high as 3,600 litres per minute, and all flow rate capacities are embodied in the present invention, including below and above the aforesaid volumes.

Mistex nozzles are manufactured of various metallic ores, for example copper, brass, AISI 304L Stainless steel; AISI 316L Stainless steel or Titanium. Nozzles are affixed to the distribution network by threading or screwing onto pipes.

Modifications and variations such as would be apparent to a skilled addressee are considered within the scope of the present invention.

Furthermore, the above inventions and design concepts applies to all water mist and water spraying nozzles whether they are used for fire extinguishment purposes or other uses, and includes nozzle designs for other liquid mediums apart from just water. The above invention also embodies the use of single orifice water mist nozzles and not just multiple orifice nozzles. Also Porta-Mist may have other applications or uses such as, for example, spraying pesticides and chemicals for treating agricultural crops, and the inventions and concepts contained herein incorporate such applications.

Claims (21)

1. Spraying apparatus comprising: nozzle means; hand held means for controlling spray of fluid from said nozzle means; storage means for storage of fluid; and delivery hose means for delivery of said fluid from said storage means to said hand held means, such that said hand held means is operable to cause said fluid, delivered to said hand held means, to be sprayed from said nozzle means.

2. Spraying apparatus according to claim 1, wherein said hand held means is substantially pistol like.

3. Spraying apparatus according to claim 1 or 2, wherein said storage means is arranged to store pressurised fluid.

4. Spraying apparatus according to any one of claims 1 to 3, wherein said storage means is provided with a pressure gauge.

5. Spraying apparatus according to any one of claims 1 to 4, wherein said storage means is provided with control means for release of fluid from said storage means.

6. Spraying apparatus according to any one of claims 1 to 5, wherein said storage means is provided with activation head means for control of flow of fluid from said storage means.

7. Spraying apparatus according to claim 6, wherein said storage means is provided with dip tube means affixed to said activation head means.

8. Spraying means according to any one of claims 1 to 7, wherein said storage means is provided with pressurisation means.

9. Spraying apparatus according to any one of claims 1 to 8, wherein said storage means is arranged to be carried by an operator.

10. Spraying apparatus according to any one of claims 1 to 8, wherein said storage means is mounted on wheels.

11. Spraying apparatus according to any one of claims 1 to 10, wherein said storage means comprises a single storage container.

12. Spraying apparatus according to any one of claims 1 to 10, wherein said storage means comprises at least two storage containers.

13. Spraying apparatus according to any one of claims 1 to 12, wherein said storage means is arranged for mounting on a vehicle.

14. Spraying apparatus according to any one of claims 1 to 13, wherein said spraying apparatus is operable in the pressure range from 7 Bar to 150 Bar.

15. Spraying apparatus according to claim 14, wherein the operating pressure of said apparatus is substantially up to 20 Bar.

16. Spraying apparatus according to any one of claims 1 to 15, wherein said nozzle means sprays said fluid therefrom as a mist.

17. Spraying apparatus according to claim 16, wherein said nozzle means is provided with chambers and jet means such that a jet means is provided in a respective said chamber and fluid delivered to said nozzle means travels into said chambers and is substantially atomised by said jet means such that said liquid is sprayed as a mist from said nozzle means.

18. Spraying apparatus according to claim 16 or 17, wherein fluid is sprayed 0 from said nozzle means in a spray pattern angle of up to substantially 180

19. Spraying apparatus according to claim 17 or 18, wherein said jet means are provided with grooves for passage of fluid which is then sprayed from said nozzle means.

20. Spraying apparatus according to any one of claims 17 to 20, wherein said jet means are provided with bore means extending therethrough for passage of fluids from said nozzle means.

21. Spraying apparatus substantially as hereinbefore described with reference to the accompanying drawings.