US3186490A - Fire-fighting method employing high expansion foam - Google Patents

Description

J1me 1965 w. B. JAMISON ETAL 3,135,490

FIRE-FIGHTING METHOD EMPLOYING HIGH EXPANSION FOAM Filed Aug. 8, 1961 2 Sheets-Sheet l FiqJ INVENTORS Will B.Jomison 8 Robert W.Bom9s 7 ATTORNEY June 1, 1965 w. B. JAMISON El'AL 3,186,490

FIRE-FIGHTING METHOD EMPLOYING HIGH EXPANSION FOAM Filed Aug. 8, 1961 2 Sheets-Sheet 2 Fig.6 ///j////./// //1 ///j//// j 72 no Fig.8

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INVENTORS Will B.Jomison 8| Roberj W. Barnes ATTORNEY United States Patent 0 3,186,490 FIRE-FIGHTING METHOD EMPLOYING HIGH EXPANSION FOAM Will B. Jamison and Robert W. Barnes, Greensburg, Pa.,

assignors, by mesne assignments, to Specialties Development Corporation, Belleville, N.J., a corporation of New Jersey Filed Aug. 8, 1961, Ser. No. 130,167 4 Claims. (Cl. 169-15) This invention relates to a fire-fighting foam system of the type adapted to deliver a high expansion foam plug into an enclosure through an opening or passageway leading into that enclosure. More particularly the invention relates to a method for quickly and easily providing a seal bet-ween the discharge end of the generator and the periphery of the aforesaid opening or passageway leading into the enclosure.

Although not necessarily Limited thereto, the present invention is particularly adapted for use with a firefighting foam generator of the type provided with a wind tunnel having a woven fabric net stretched across one end and a fan or the like at the other end which forces air axially through the tunnel. Between the fan and the net are one or more nozzles which spray a solution containing a wetting or foaming agent onto the net. When the foaming agent is thus sprayed onto the net and air forced through the tunnel, a foam plug having an expansion ratio as high as 1500 to l is formed which is particularly adapted to fight fires in mines and buildings where the blaze is not readily accesssible.

In mine fires, for example, the actively flaming fire front is highly inaccessible due to the fact that it is protected from attack from its forward end by the advance of heat and fumes, and from the other end by smoke, hot strata, and obstructed roadways. A water jet from a conventional fire hose is usually unsatisfactory for fighting underground mine fires due to the lowness of the mine .roof which limits the range of the jet. In many cases, such mine fires can be extinguished only by sealing a portion or all of the mine for months in an effort to shut olf the supply of oxygen to the fire. This method, however, is unsatisfactory for many reasons. In addition to the loss of production during the time that the mine is sealed, there is always the danger of explosion within the sealed portion of the mine, as well as the possibility of the outbreak of fresh fires once the seal is broken.

By employing a foam plug of the type described above, however, the mass of bubbles formed by the generator will fill the entire cross section of the mine roadway and travel down the roadway to the fire zone where the foam forms steam which eventually smothers the fire. By employing this method, the problem of access to the fire zone is eliminated since the foam-generating equipment may be spaced at a considerable distance from the blaze. Furthermore, the foamplug can effectively travel around corners so that the foam-generating equipment need not be positioned along a straight-line path with respect to the fire zone as would be the case, for example, with a water jet from a fire hose.

Many of the same problems which hinder the fighting of mine fires are also present with fires in buildings and other enclosures. In the past, the most commonly used method for fighting fires in buildings and other places Where the fire zone was not easily accessible usually consist-ed of attempting to spray a jet of water onto the blaze by means of a hose or some type of automatic sprinkler system. This method, however, is not alto gether satisfactory. In the case of a fire hose, heat, smoke and other obstacles make it extremely difficult to 3,186,490 Patented June 1, 1965 get close enough to the fire zone where the water jet can be effectively directed onto the blaze. In many cases, the most that can be done with a fire hose is to spray the area surrounding the blaze in the hope that the fire will not spread to other parts of the building. Even if the building is equipped with an automatic sprinkler system, the resultant damage caused by the water is oftentimes greater than the damage done by the fire itself. By employing a foam plug of the type described above, however, the problem of water damage is greatly reduced since, although the foam fills the entire area of the building surrounding the fire, its water content is relatively small and does not soak furniture and other fixtures within the building. Furthermore, the

problem of directing a water jet onto the fire zone is likewise eliminated.

In order to effectively drive a foam plug down a mine roadway or into the interior of a building, it is necessary to provide a seal between the discharge end of the foam generator and an opening leading to the fire area. In forcing a foam plug down a mine roadway, for example, a back pressure is developed which, in the absence of a seal, will stop the forward advance of the foam plug and eventually cause it to move backwardly and envelop the generator; whereupon the foam will simply recirculate through the generator without being driven further down the mine roadway. Although the foam generator itself is highly portable and erects quickly and easily, the work of building a seal between the discharge end of the generator and the walls, floor and roof of a mine roadway requires an appreciable amount of time. The seal is usually made of tightfitting boards; and because of the relatively high pressures involved, the boards must be fitted to the ragged rock or coal, and the joint between the wood and rock stulfed with burlap or plaster. Also, the seal must have substantial strength .as the pressure buildup can exert a tremendous force upon the seal, as much as fifty pounds per square foot. Because of these requirements, the seal must be carefully made and even trained crews, with all necessary material on the site, require at least fifteen minutes for this work. Untrained crews require thirty minutes to two hours, meaning that there is an appreciable delay in preparing to fight a mine fire.

Similarly, in fighting building fires with high expansion foam, the discharge end of the foam generator must be tightly sealed to the building or other enclosure which contains the fire. Otherwise, much the same problems will be encountered as are present in the case of mine fires. That is, if a seal is not provided between the d scharge and inlet ends of the generator, the foam cannot be effectively driven into the building.

As an overall object, the present invention seeks to provide a method for readily providing a seal between the discharge and inlet ends of a foam generator without requiring the erection of a wall of boards or the like by trained crews.

In accordance with the invention, a tube of flexible material is connected to the discharge end of the foam generator such that the foam will be forced into one end of the tube and out through the other end while thetube is expanded by the foam. If the cross-sectional area of the tube is larger than the mine roadway or the opening leading into a building, it will seal tightly to the rough surfaces of the mine roadway or the edges of the building opening and prevent the foam from making its way back to the air inlet of the foam generator. Preferably, the tube is reasonably long and strong enough to be able to withstand the pressure. In the case of building fires, a long tube is particularly useful. For example, the tube can be fifty or one hundred feet long, meaning that the generator can 139 be located at a considerable distance from the building and the foam conducted into the building through a door or window through the long, flexible tube. As will be understood, when foam is driven through the tube, the tube expands and, being larger than the opening, seals the opening completely and tightly.

The above and other objects and features of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings which form a; part of this specification, and in which:

FIG. 1 is a cross-sectional view of one type of fire-fighting foam generator with which the present invention may by used;

FIG. 2 is a side view of an embodiment of the inven tion adapted for use in fighting building fires;

FIG. 3 is a top view of the embodiment of the invention shown in FIG. 2;

FIG. 4 is a cross-sectional view showing the manner in which sections of the tube illustrated in FIGS. 2 and 3 may be zippered together;

FIG. 5 illustrates the manner in which a tubular section of increased diameter may be connected to the end of a foam-conveying tube of 7 smaller diameter to facilitate openings of large cross section;

FIG. 6 is an illustration of another type of fire-fighting foam generator, particularly adapted for use in mines, to which the sealing means of the present invention is attached;

FIG. 7 is a sectional view illustrating the position of the foam-forming net and the solution-spraying nozzles of the fire-fighting foam generator shown in FIG. 4; and

FIG. 8 is a top view of the embodiment of the invention shown in FIG. 6.

Referring now to the drawings, and particularly to FIG. 1, the embodiment of the invention shown comprises a wind tunnel it) which is fabricated from three sections 12, 14 and 16. Sections 12 and 16 may be rectangular or circular in cross section, depending upon requirements, and have theircross-sectional area fixed along their lengths. Section 14, however, is tapered and connects section 12 of larger cross-sectional area to section 16 of smaller cross-sectional area. As shown, bolts or other similar fastening means may be used to secure the respective sections together. Positioned within section 16 of small cross-sectional area is a fan 18 having a rotary head 20 with a plurality of fan blades 22 fixed thereto. Fan 18 is also provided with a stationary housing 24 having a plurality of vanes 26 extending radially outwardly toward the wall of section 16. As will be understood, the fan 18 creates an air current which travels through the wind tunnel from left to right as shown in FIG. 1.

One end of section 12 has connected thereto a short section 28 which carries a corrugated foam-forming net;

30. A plurality of horizontally-extending support rods 32 are staggered along the height of the outlet of the wind tunnel 10 and are carried in the sides of section 28 whereby the net 30 may be stretched around the various support rods in a zig-zag pattern as it extends across the discharge end of the wind tunnel. The upper and lower ends of the net are reinforced as at 34 and 36 and are secured to the short section 28 by means of rivets 38 or any other suitable fastening means.

Intermediate the fan 18 and the net 30 are a pair of nozzles 40 and 42 connected through a conduit 44 to a valve or other similar liquid proportioning device 46 which serves to mix water from conduit 48 with a wetting or foaming agent from conduit 58. Any suitable wetting agent in conduit 50 may be used which will generate bubbles on the net 30. However, as an example, 30% active ammonium lauryl sulphate dissolved in water in a proportion of about active material by weight to give a concentrate in conduit 50 which is then mixed with water in conduit 48 at a rate of about 3% by volume has been found to give sufliciently good results in generating the foam material.

In operation, the solution containing a wetting agent is sprayed by nozzles 40 and 4-2 onto the net 3! while fan 18 forces air through the wind tunnel 10. When the net 33', through which air from fan 13 is passing, is sprayed on one side with the solution from nozzles 40 and 42, foam will be formed on the right side of the net as viewed in FIG. 1. This foam is produced by the air blowing bubbles from films of liquid which are stretched over the holes or apertures in the net. Although the foregoing description should suffice for purposes of the present application, a full and detailed description of the manner in which the bubbles are formed at the net 30 may be had to copending application Serial No. 13,103, filed March 7, 1960.

Although a pleated or zig-zag net 39 is shown in the embodiment of FIG. 1, it should be understood that for purposes of the present invention, any net or screen may be employed which will form a high expansion foam plug by blowing bubbles from films of liquid stretched across the apertures in the net or screen. The velocity and pressure of the air passing through wind tunnel 10 may be controlled by either varying the speed of the fan 18 or by adjusting a variable vane damper, schematically illustrated in FIG. 1 at 52.

Referring now to FIGS. 2 and 3, an embodiment of the invention is shown wherein a foam generator 54, similar to the generator shown in FIG. 1, is mounted upon a truck 56 and has a flexible tube 58 connected to its discharge end. The tube 58 may be formed from a nylon reinforced plastic fabric; however any other suitable flexible material may be used which is strong enough to withstand the pressures produced. In many cases a cotton fabric is preferable, the cotton material having the ability to be wetted by the foam moving within the tube so as to protect the fabric from the heat of a fire. If the generator of FIG. 1 is employed, the tube will be connected to section 28 by any suitable means so as to provide an air-tight seal between the periphery of the tube and the periphery of the discharge end of the generator. In this case, the generator is employed to extinguish a fire within a building 60 having an opening, such as window 62 therein. As will be seen, the full cross-sectional area of the tube 53 when inflated must be greater than the area of the window or other opening leading into the building. Preferably, the tube 58 is formed in sections which are zippered or otherwise fastened together as at 59. This enables the use of standard sized sections which may be fastened together to form a composite tube of any length, and also facilitates the use of a larger diameter section which may be connected to the forward end of the tube 58 for exceptionally large openings as will hereinafter be explained.

The manner in which sections are zippered together is shown in FIG. 4. Thus, the opposite sides 61 and 63 of the zipper are sewed to adjacent tubular sections 65 and 67, while a flap 69 is sewed to the forward section 65 whereby the foam traveling in the direction of the arrow will cause the flap to seat against the inner periphery of the tube and cover the zipper connection so as to prevent the escape of air under pressure and/or liquid therethrough.

When not in use, the flexible tube 58 will be collapsed or deflatedand may be rolled up and stored, for example, on the truck 56. For increased length, additional sections will be carried on the truck such that any desired number of sections may be connected to the end of the tube to effect the required length as by the zipper arrangement described above. During setup of the equipment, the tube which is collapsed or deflated at this time will be connected at its one end to the generator 54, unrolled along the ground toward the building and additional sections connected if necessary so that its other end may be inserted into the opening 62. Thereafter, the foam generator 54- is turned on whereby the tube will inflate or expand as shown in FIGS. 2 and 3 and since the crosssectional "area of the tube is larger than that of the window 62 or other building opening, it will form a tight seal around the periphery of the opening and prevent foam 64 which is discharged into the building from being forced back out through the opening. Thus, an effective seal is formed between the interior of the building and the foam generator so as to enable the foam plug 64 to be effectively driven into the building to the fire zone where it will extinguish the blaze. In the case of building fires, a long tube is particularly useful, thereby enabling the foam generator 54 to be located at a safe distance from the building 60. The length is not critical, and it has been found that the tube can be anywhere from twenty-five to one hundred feet long. In all cases, however, the tube, whatever its length, must be larger in cross section than the opening in the building through which the tube is placed. When foam is driven through the tube, the tube expands and, being larger than the opening, seals the opening completely and tightly.

There is an upper limiting velocity at which the foam can be driven through tube 58, depending upon the expansion ratio of the foam produced. For a 1000 to 1 expansion ratio foam (i.e., 1000 volumes of air to 1 volume of liquid), which ratio has been found particularly useful in fighting fires, the velocity of the foam in the tube should not exceed about 1000 feet per minute and should preferably be about 750 feet per minute. Higher velocities than 1000 feet per minute will tear or break the bubbles, thus destroying the foam. Foams of lower expansion ratios can stand higher velocities, since these foams are formed of smaller and tougher bubbles. Conversely, foams having expansion ratios higher than 1000 to 1 must be moved at lower velocities. The expansion ratio may be regulated by adjusting the amount of liquid delivered to nozzles and 42 through valve 46 (FIG. 1) and the velocity of air stream may be adjusted by regulation of damper 52 and/ or the speed of fan 18.

When the tube is to be placed in a large opening, such as the garage door 71 shown in FIG. 5, a short tube section 73, which will connect to the standard diameter. tube 58 and which expands to a size larger than the large opening 71, is attached to the standard tube as at 75, inserted in the opening and expanded by the foam, thereby making an effective connection to the large opening.

Referring now to FIGS. 6, 7 and 8, the embodiment of the foam generator shown therein is similar to the embodiment of FIG. 1 in that it includes a fan 66 carried within housing 68 and has a foam-forming net position within an adjustable frame 70 which is connected to the housing 68 through a flexible tube 80. This embodiment of the invention is particularly adapted for use in a mine roadway having an upper wall or ceiling 72 and a lower wall or floor 74. The housing 68 containing the fan 66 is provided with spoked steel wheels 76 and a handle 78 whereby the apparatus may be easily transported over the mine floor 74. As shown, the frame 70 which contains the foam-forming net is provided with the tunnellike extension 80 having walls of rubber or plastic-imbedded fabric or other similar flexible material. The end of extension 80 opposite frame 70 is provided with a flange 82 which may be secured to a flange 84 on the exit end of housing 68 by means of bolts 86 or other suitable fastening means. With this arrangement, the frame 70 and its extension 80, which are much lighter than the housing 68 and the fan 66 which it carries, may be disconnected from the housing and transported separately. On each side of the frame 70 are a pair of adjustable colurnns 88 which may be varied in height to accommodate the distance between the ceiling 72 and floor 74.

As shown in FIG. 7, the frame 70 is similar in construction to section 28 shown in FIG. 1 and is provided with a plurality of horizontally-extending rods 90 around which a woven foam-forming net 92 of high-water absorbing capacity is stretched in a pleated or zig-zag pattern.

6 Like the embodiment of FIG. 1, the ends of the net are reinforced as at 94 and 96 and secured to the frame 70 by means of rivets 98. In this case, however, the nozzles are supported on a bracket 100 which, in turn, is carried on the frame 70. Nozzles 102 and 104 communicate with a hose 106 which may be connected as at 108 (FIG. 6) to a conduit for supplying a wetting agent solution to the nozzles.

As was previously explained, it is necessary to provide a seal between the discharge end of the foam generator and the walls, ceiling and floor of the mine roadway. Otherwise, a back pressure is developed which, in the absence of a seal, will stop the forward advance of the foam plug and eventually cause it to move backwardly and envelop the generator, whereupon the foam will simply recirculate through the generator without being driven down the mine roadway. That is, it will simply be recirculated through housing 68 and the extension 80. Previous to this invention, it was customary to erect a vertical shield between the outer periphery of frame 70 and the walls, ceiling and floor of the mine roadway. However, as was explained above, this is a cumbersome and time consuming procedure which is altogether unsatisfactory and necessitates an appreciable delay in preparing to fight a mine fire.

In accordance with the present invention, the seal between the periphery of frame 70 and the periphery of the mine roadway is provided by means of a tube 110 having its one end connected to the periphery of frame 70 between flanges 112 and 114. As will be understood, the cross-sectional area of the tube 110, when inflated, is greater than that of the mine roadway, meaning that the end of the tube which is connected to the frame 70 must be pinched or pleated in order to form a tapered area in the tube. Preferably, the tube, like that of FIGS. 2 and 3, is formed from a nylon reinforced plastic fabric, however any other suitable flexible material may be used, depending upon requirements. The tube must be reasonably long and strong to be able to withstand the pressure developed by the fan 66 and must be flexible enough to conform reasonably to the rough surfaces of the mine roadway.

With the arrangement shown, the housing 68 which carries fan 66 will be initially moved into position and the frame 70 erected by means of the adjustable columns 88. Thereafter, the flange 82 on extension 80 will be secured to flange 84 on housing 68 by means of bolts 86. Preferably, the tube 110 will be permanently attached to the frame 70 between flanges 112 and 114 and may be stored with the frame as an integral unit.

Assuming that the unit has been assembled, the fan 66 is thereafter turned on whereby air is forced through the corrugated net 92 while inflating the flexible tube 110. Preferably, the tube 110 will be extended along the mine roadway before the fan is turned on. As the air is forced through the corrugated net, the foam plug will be formed at the discharge end of the generator. At the same time, the tube 110 will be expanded or inflated whereby it will conform to the periphery of the mine roadway. The foam plug thus formed travels through the tube 110 until it reaches the discharge end thereof as at 116 (FIG. 8) and travels down the mine roadway to the fire area where it eventually forms steam which smothers the fire. Since the tube 110 expands outwardly into abutting relationship with the periphery of the mine roadway, it forms an effective seal between the discharge end of the tube and the foam generator to prevent the back pressure from causing the foam plug to move backwardly and envelop the generator.

Although the invention has been shown in connection with certain specific embodiments, it will be readily apparent to those skilled in the art that various changes in form and arrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention.

We claim as our invention:

1. In the method for fighting fires in an enclosure having an entry leading into the enclosure; the steps of inserting the discharge end of a collapsible tube into the enclosure through said entry, and under air pressure forcing foam having an expansion ratio as high as 1500 to 1 into the intake end of saidncollapsible tube and through the collapsible tube to cause it to become inflated and expand to fill the cross section of said entry to provide a seal around said entry. 1

2. In the method for fighting fires in an enclosure having an entry leading into the enclosure; the steps of inserting the discharge end of a collapsible tube into the enclosure through said entry, and under air pressure forcing foam having an expansion ratio as high as 1500 to 1 into the intake end of said collapsible tube and through the collapsible tube to cause it to become inflated and expand to completely fill the cross section of said entry with the wall of the tube in abutment with the periphery of the entry to thereby provide a seal around said entry and prevent foam from being discharged through said entry.

3. In the method for fighting fires in an enclosure having an entry leading into the enclosure; the steps of inserting the discharge end of a collapsible tube into the enclosure through said entry, spraying a solution containing a foaming agent onto one side of a foam-forming not having orifices extending therethrough, forcing an air stream through the net whereby the air stream will travel from one side of the net to the other side through said orifices while blowing bubbles from films of the foaming agent-containing solution stretched over the orifices in the net whereby a mass of bubbles will be formed at the net,

and under the effect of said air stream forcing the mass of bubbles formed at the net through said collapsible tube to cause the collapsible tube to become inflated and expand to fill the entire cross section of said entry and provide a seal around said entry.

4. The method for fighting fires in an enclosure having an entry leading into the enclosure with the use of foam having an expansion ratio as high as 1500 to 1, the foam being generated by a foam generator comprising a wind tunnel having foam-forming means at the discharge end thereof, and means at the intake end thereof for forcing air through the tunnel, which comprises the steps of inserting the discharge end of a collapsible tube into the enclosure through said entry, the intake end of said tube being connected to the discharge end of said foam generator, and causing foam formed at said foam-forming means to pass through said collapsible tube to inflate the same and expanded to fill the cross section of said entry to provide a seal between the discharge end of said tube and said foam generator.

References ited in the file of this patent UNiTED STATES PATENTS 133,044 Libby NOV. 12, 1872 789,315 Bergstrom May 9, 1905 2,003,732 Bins June 4, 1935 2,097,663 Hersey et al Nov. 2, 1937 2,129,105 Spence Sept. 6, 1938 2,198,585 Urquhart et al Apr. 23, 1940 2,202,459 Link May 28, 1940 2,413,997 Rosa Jan. 7, 1947 2,480,441 Bingham Aug. 30, 1949 2,753,876 Kurt July 10, 1956 2,788,231 Crow Apr. 9, 1957 3,065,797 Barnes Nov. 27, 1962 OTHER REFERENCES Controlling Mine Fires With High-Expansion Foam, Nagy, Murphy and Mitchell, US. Bureau of Mines, published July 1960, pages 23 to 26.

Laboratory Report of Factory Mutual Research Corporation No. 14495/2241 (March 29, 1961, from Safety Development Corporation).

Practical Aspects Of Controlling An Underground Fire 'On A Mining Machine, Mitchell, Murphy, Nagy and Christofel, US. Bureau of Mines, published Aug. 5, 1961, pages 7-9.

Firefighting'in Underground Roadways, Eisner and Smith, British Ministry of Fuel and Power, pages 6 and 12.

Claims (1)

1. IN THE METHOD OF FIGHTING FIRES IN AN ENCLOSURE HAVING AN ENTRY LEADING INTO THE ENCLOSURE; THE STEPS OF INSERTING THE DISCHARGE END OF A COLLAPSIBLE TUBE INTO THE ENCLOSURE THROUGH SAID ENTRY, AND UNDER AIR PRESSURE FORCING FOAM HAVING AN EXPANSION RATIO AS HIGH AS 1500 TO 1 INTO THE INTAKE END OF SAID COLLAPSIBLE TUBE AND THROUGH THE COLLAPSIBLE TUBE TO CAUSE IT TO BECOME INFLATED AND EXPAND TO FILL THE CROSS SECTION OF SAID ENTRY TO PROVIDE A SEAL AROUND SAID ENTRY.

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