US1787792A - System for extinguishing fire in oil tanks - Google Patents

Description

Jam 6, FLQEL s. MOSER 138K792 SYSTEM FOR EXTINGUISHING FIRE IN OIL TANKS Filed Sept. 22, 1926 2 Sheets-Sheet 1 Jam, W33, 5. MQSER 7 1,787,792

SYSTEM FOR EXTLNGUISHING FIRE IN OIL TANKS Filed Sept, 22, 1926 2 Sheets-Sheet 2 Patented Jan. 6, 1931 UNITED STATES PATENT OFFICE sruaar Moses, or BERKELEY, canmonn'm, assrenon TO sTANnAn-n'on. comramr or camronnm, or SAN raANcIsoo, CALIFORNIA, A conronarron or DELAWARE SYSTEM. FOR EXTINGUISHING FIRE IN OIL TANKS Application filed September 22, 1928. Serial No. 137,013.

. This invention relates to methods of and systems for extinguishing fires in oil tanks, and anobject of the invention, in general, is

' to make the application of the firefoam to the 5 burning oil more effective. p F irefoam is a tough foam generally composed of bubbles of carbon dioxide trapped in a binder that comprises an aqueous solution of organic and inorganic foaming agents, such as licorice, glucose, aluminum hydroxide, or the like. The production of firefoam by the mixing of two solutions or prepared dry chemicals and water is familiar to those skilled in this art. The firefoam, when applied to an oil fire, smothers the fire by forming a more or less impervious blanket which floats upon the surface of the oil. The water in the irefoam acts as a cooling agent, tending to reduce the temperature of the oil; the foam blanket checks the rise of combustible vapors from the heated oil; the carbon dioxide dilutes such vapors as pass through the foam; and the foam blanket cuts off from the oil radiant heat from the flames already prevailing above the oil, thereby preventing further vaporization of oil an consequent formation of further supplies of combustible gases. In order to prevent the admixture of oil with the fire'foam, thus to secure the best re-- sults, I introduce the firefoam smoothly to the oil in the tank in such manner that it does not mix with the oil nor force its way beneath the surface of the oil. -It will be readily understood that the admixture of oil with firefoam is extremely deleterious to the extinguishing action of the'firefoam since the oil reduces the tenacity of the film holding the bubbles together. Furthermore, foam which has becomecontaminated withoil is sloppy, heavy, wet and easily broken up, whereas foam uncontaminated with oil is extremely light and fiufiy and is very resistant to being stirred, dropped or otherwise acted upon. Also, foam that is contaminated with oil is, of course, a poor retardant of fire as it contains a combustible substance.

The foam is better protected from the action of the flames when in an unbroken mass than it is when scattered into small fra ments, as such small fragments tend to quickly evapo rate. Such fragments that do not actually evaporate are rapidly dissipated so as to break up the blanket formation. Thus, it will be seen that the difference in results secured from applying the firefoam properly and applying it improperly is very great.

' Many unsuccessful attempts in extinguishmg fires by the use of firefoam would have PI'OVGII successful had the foam been properly applied and, furthermore, even where the fire has been successfully extinguished by improper application of the firefoam, such improper application has resulted in the use of excessive quantities of the foam.

The ordinary method of applying firefoam to burning oil in a tank consists in dischargmg the firefoam from a box positioned at the top of the tank. The foam thus is required to fall from the top of the tank to the surface of the oil which may be at a considerably lower level than the top of the tank. In some instances, the box from which the firefoam is discharged is arranged to'deflect the foam against the inner wall of the tank. It will be seen that, in either case, the foam develops a relatively high velocity before it strikesthe surface of the oil and, accordingly, tends to be driven by its velocity beneath the surface of the oil. Also, because of the distance that the firefoam t'ravelsbefore its reaches the surface of the burning oil, much of the foam is evaporated and much of it is dissipated into small particles.

Attempts have been made to slow down the velocity of the falling firefoam by installing ladder-like structures beneath the foam box. Such structures have been of little benefit as they have reduced the velocity very slightly and have not served to protect the firefoam from the heat and draft of the flames. Moreover, such ladder-like or other fixed structures inside an oil tank would, in many instances, be destroyed or made useless because fires in oil tanks are often started by an explosion which blows the roof of the tank into the air. Sometimes, the roof falls back into the tank and smashes everything beneath it.

Even when the tank is nearly full of oil,

the ordinary foam applying box discharges the foam downwardly into the oil at such high velocity as to cause contamination of the foam with oil and, it will be readily seen, that the contamination increases the further the oil level is from the top of the tank.

Another object of this invention is to apply the firefoam at a relatively low velocity close to the surface of the oil in the tank.

Another object is to protect the foam from the heat and draft of the flames until said foam reaches the oil surface.

Another object is to provide a system for applying firefoam to the oil surface which,

will not be rendered inoperative by explosions resulting in fires.

The accompanying drawings illustrate several embodiments of systems constructed in accordance with provisions of the invention and capable of performing the newly invented method:

Figure 1 is a side elevation of a system for extinguishing fires in oil tanks, a fragment of the tank with which the system is used also being shown.

Figure 2 is an enlarged fragmental side elevation of the upper portion of the system shown in Figure 1, the flexible nozzle being in folded osition above the tank, a. fragment of which is shown.

Figure 3 is an enlarged broken vertical section of the flexible nozzle. 7

Figure 4 is an enlarged detail of the latch mechanism and its supporting clamp for holding the nozzle elevated.

. Figure 5 is a side elevation of another form of the invention, a fragment of the tank with which the system cooperates also being shown.

, Figure 6 is an enlarged sectional detail on the line indicated by 6-6, Figure 5.

Figure 7 is a side elevation of a third modification of the invention, a fragment of the tank with which the system cooperates also being shown.

First referring to the form of the invention illustrated in Figures 1 to 3 inclusive, 11 indicates a light, strong tube constructed of a steel alloy or other suitable material having relatively great strength and being high in heat resistance. This tube is fed with the desired chemical solutions, for producing firefoam, through supply pipes 12, only one of which can be seen in Figure 1 from the nature of the view. Connected with the pipes 12 are hoses 13. The tube 11 is preferably provided at its lower end with a spiked skid or skids 14, the spikes being indicated at 141 on the lower part of the skid for engaging the earth to prevent slipping of the skid. Fastened to the tube 11 near its upper end are guycables 15 and poles 16 for assistin in erecting the tube into position alongside of an oil tank, a fragment of which is indicated at A. Preferabl tube 11 is of sectional construction to acilitate handling thereof and also to allow of the erably strengthened by wire insertion and/or by longitudinally ,extending steel cables 19 which are preferably fastened to the inside surface of the tube 18.

The tube 18 carries just beneath its lower end, which is flared as indicated at 191, a

nozzle bag or foam receiver 20 and, when the system is in correct position for use in extinguishing a fire in the tank, the bag 20 is positioned slightly above the surface B of the oil. The function of the bag 20 is to receive the firefoam from the tube '18, reduce the velocity bf said firefoam, and cause said foam to flow smoothly onto the oil surface. be best seen in Figure 3. The bag 20 is preferably constructedof reenforced incombustible fabric and has a flat bottom 21 supported by the cables 19 which are secured thereto at 22. The sides 23 of the bag 20 are aslant inwardly and u wardl thus constricting the bag upwar ly an said sides are supported by a plurality of cables 24 which are secured at their up er ends to the tube 18 and cables 19. The ca les 24 may, as suggested in Figure 3, extend beneath the bag 20 to form loops supporting the bottom of the bag. The ottom of the bag being closed at the outlet end of the tube 18, it will be readily understood that the velocity of the firefoam falling through the tube 18 is checked by the foam striking the flat bottom. The reentrant sides 23 of the bag prevent the foam from spattering in small particles over the rim of the bag, thus insuring against dissipation of the foam. The sides 23 also produce turbulence which further checks the remaining energy in the foam discharged into the bag. The foam, thus deprived of all of its original velocity acquired. at least in part, by falling from the level of the top of the tank into the bag, fills the bag and wells slowly and uniformly out of the large mouth 25 of the bag and onto the oil surface B. The firefoam thus discharging from the bag mouth 25 impinges upon the surface of the oil under such low hydraulic head that the foam neither mixes with the oil nor penetrates beneath the surfacethereof but spreads over the oil surface, thus completely blanketing the same. with a tough foam in. an unbroken mass.

\Vhen the system is being installed in connection with a tank, the nozzle will be folded up somewhat .-in the manner indicated in Figure 2 until the tube 11 is in position with the curved portion 17- extending over the edge of the tank and the folded nozzle will be maintained in folded position during this This may operation by suitable means as, for example, a cable 26 secured at one end to a slide or pin 27 mounted in a supporting block 28 which is pivoted at 29 to the upper end of a clamp 30 that is attached to the tube portion 17. The cable 26 passes beneath the folded tube and the receiver and is anchored at-its other end to the lower end of the clamp 30. The upper end of the pin 27 projects beyond the upper end of the block 28 and through the projecting end passes a cotter pin 31 to which is connected a releasing line 32. After the tube portion 17 is in position over the edge of the tank, the releasing line 32 will be pulled, thus pulling out the cotter pin and permitting the pin 27 to slide out of the block 28, thereby releasing the cable 26 and permitting the nozzle to drop into the tank.

Now referring more particularly to Figure 5 for another modification of the invention, there is provided a trussed carriage 33 having wheels 34. If necessary for counterbalancing purposes, the carriage may be provided near its rear end with a counter weight 35. The forward end of the'carriage constitutes a tower 36 and mounted on the upper end thereof isa foam mixing chamber 37. The chamber 37 is mounted on hollow trunnions 38, and the tower 36 is formed in part by pipes 39 which connect with the trunnions 38. The pipes 39 are supplied with the firefoam forming chemicals through hoses 40 connected with the lower ends of said pipes. Depending from the mixing chamber 37 is a sectional tube 41, the sections of which telescope.- Said tube sections are constructed of suitable fire resistant material, and the lowermost section carries a receiver 42 similar in shape to the bag 20 though, in this instance, it is made ofmetal. The lowermost tube section and the receiver 42 together constitute a discharge noz'zle similar to that hereinabove described. This receiver is mounted on a hollow metal float43 capable of supporting a part or all of the load of the telescoping tube and foam receiver. A, hoisting cable 44 is secured to the lower end of the lowermost tube section and extends through the telescoping tube to the upper end of said tube where it passes through a stufiing box 45, thence'over a pulley 46, the axis of which substantially coincides wit-h the axis of the trunnions, From the pulley 46, the cable passes to a winch 47 mounted on the carriage 33. It is to be understood that the carriage 33 will be rolled into position alongside of a tank into which the foam is to be discharged, with the telesco ing tube in contracted condition. When t e tube is over the tank, the winch will be operated to lower the sections so as to expand the tube and permit the float to rest on the oil within the tank. The float, though it can be omitted, insures of the correct positioning of the foam receiver close to the surface of the oil.. If the float is not employed, the height of the foam receiver can be determined by gage marks on the hoisting cable 44.

The two embodiments of the invention described above will be placed in position after the fire is started in thetank and, accordingly, are not subjected to destructive effects through collapse of the tank roof. The invention may be embodied still differently in a form that is in permanent position on the tank, as illustrated in Figure 7. In this figure, a mix.- ing chamber is indicated at 48 and is solidly secured to the tank shell 49 and but lightly connected to the tank roof 50 in order that when the roof is blown off by an explosion in the tank, the mixing chamber will not be carried away with the roof. The chamber 48 is fed with foam-producing chemicals through the pipe lines 51. A tube 52 of telescoping sections is suspended from the box 48 and is of similar construction to the tube 41, above described. Also, there is a foam receiver 53 and float 54, similar to the above described receiver 42 and float 423. A cable 55 inside of the tube 52 is operated to contract and expand the tube and is operated the same as the cable 44 in Figure 4, the operating means for the cable 55 not being shown because of the nature of the view. In contracting and expanding the tube 52, the receiver and float 54 are guided by guides 56 which are secured to the bottom of the chamber 48 and to the bottom of the tank 49.

From the foregoing, it will be readily understood that the flrefoam is discharged into the tank immediately above the surface of the oil therein and beneath the flaming gases evolved from the oil irrespective of the height of the oil level, that the firefoam is shielded from the flame above the discharge level, that the firefoam is caused to fl-ow downwardly through the zone of fire. thence upwardly and outwardly, and, furthermore, that the firefoam is caused to flow onto the surface of the oil at alower velocity than its initial velocity.

I claim: o

1. A system for extinguishing fire in an oil tank comprising means for introducing fire foam over the top of the tank wall, means for conducting the firefoam downwardly, a receiver connected with the lower end of the conducting means for checking the downward velocity of the firefoam and discharging it with low upward and horizontal velocity, and a means to adj ustably support the receiver with its discharge slightly above the surface of'oi-l in the tank.

2. A system for extinguishing fire in an oil tank comprising a portable member for 425 after said portable member is erected, means on the end of said tube for deliver of firefoam with low discharge velocity rom said extensible tube to the oil surface, and means 0 support the last mentioned means in position to discharge at the oil surface.

3. A system for extinguishin fire in an oil tank comprising a portable b0 y ortion, an extensible tube of fire resistant abric connected to said body portion, means on the end of said tube for delivery of firefoam with low discharge velocity to the oil surface, and means to support the last mentioned means in position to discharge at the oil surface.

4. A system for extinguishing fire in an oil tank comprising a portable body portion, an extensible tube of fire resistant fabric, a receiver connected with the extensible tube and adapted to destroy the vertical velocity of the firefoam and discharge it with low horizontal velocity, and means to support the receiver in position to discharge at the.

oil surface.

5. A system for extin uishing fire in an Ill tank comprising a refoam producing chamber, an extensible tube, and a receiver depending from said extensible tube, said receiver consisting of a vessel having a relatively flat bottom spaced from the lower end of the tube and walls sloping in toward the top.

6. A system for extin uishing fire in an oil tank comprising a f irefoam producing chamber, an extensible tube, a firefoam receiver connected with the extensible tube, a tripping device for causing extension of said tube after it has been placed in position over the wall of the oil tank, and means to support the receiver in position to discharge at the oil surface.

7. In a system for extinguishing fire in an oil tank comprising a firefoam producing chamber, an extensible tube of flame resisting fabric connected to said chamber and having an outlet at its lower end, a bracing for said tube composed of metal cables so disposed as to be cooled by the flow of firefoam, and a means to limit extension of the tube to the level of the oil in the tank.

8. A system for extinguishing fire in an oil tank comprising a firefoam producing chamher, and anextensible tube, a firefoam receiver spaced from the lower end of the tube for discharging firefoam near the oil surface and means to support the receiver at the oil surface.

9. A system for extinguishing fire in an oil tank comprising a light portable metal tube provided with bottom skids, means for introducing firefoam producing chemicals into said tube, poles connected with the tube for erecting the tube against a tank shell, the tube provided with a curved upper portion, a collapsible tube depending from the curved portion and made of fire resisting fabric and provided at its lower end with a bag adapted to destroy the vertical velocity of the firefoam and to dischar e it without splattering but with low upwar and horizontal velocity near the burning oil surface, and means to support the bag at the surface of the oil in the ta 10. A system for extinguishing a fire in an oil tank comprising a receiver, means to support the receiver close to thesurface of oil in the tank, said receiver provided with an outlet mouth, and means of less cross sectional area than the receiver to supply firefoam to the receiver below the level of its outlet mouth.

11. A system for extinguishing a fire in an oil tank comprisin a receiver, means to support the receiver 0 ose to the surface of oil in the tank, said receiver provided with an outlet mouth, means of less cross sectional area than the receiver to supply firefoam t0 the receiver below the level of its outlet mouth, and means to raise and lower the receiver.

Signed at San Francisco this 13th day of September, 1926.

STUART MOSER.

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