US2548409A - Foamite fire-extinguishing system - Google Patents

Description

April 10, 1951' c. H. TROTTER ET AL FOAMITE FIRE EXTINGUISHING SYSTEM Filed Nov. 14, 1949 Y 2 Sheets-Sheet 1 INVENTORS C H. TROTTER A.W. SWEENEY BY I A TTORNEVS April 10, 1951 c. H. TROTTER ET AL 2,548,409

FOAMITE FIRE EXTINGUIS-HING SYSTEM Filed Nov. 14, 1949 2 Sheets-Sheet 2 INVENTORS C. H TROTTER A. W. SWEENEY BY Maw A TTOR/VE Y5 Patented Apr. 10, 1951 UNITEDJ- STATES RATENT OFFICE FonMrrE nanm f iirsnme srsruM" I Claude n. Irma and Arthur; w; Sweeney; emu lips Tex assignorsa-tmfhillips .-Petroleum..0om=,- pany, alcorporationlof Delaware;

Ap licatiomNovemben-H, 1949'; SeriaFNo'; 127,17 2

6lClaimS;-- (Cl.e169-4)1:

possess relatively large vapor spaces, that-is; any; portion ofethe tank notfilledwith liquid will be filled; with 1 vapors .of the-liquid in. .case theeliduid;

stored "is volatile; When such aliqui-d is pumped from-the tank and if air. displaces .thediquid, an"

explosive mixture-may then exist within the vapor space.- of the tank.-. In: order. to avoid such dangerous conditions, the. floating roof Iwas rde-w vised= for use in tanks in whichare to be stored such inflammable liquids as. gasoline; The float-- ingroof-has been used in the. oil industry for many years.

Fires in. tanks are alsdcaused as .-a result of the storage :of: liquids containing hydrogen sulfide.: H-ydnogensulfide inthe oil' reacts with the iron or iron rust on the tank walls ,to form an iron sulfide; When. the .tank roof. descends this iron. sulfide dries and. becomes: pyrophoric. Ig-- nitionis spontaneousandaitank fireresults-when.

, inflammable vapors I are present.

Floating roofs are. so constructed;that-upon filling'or emptying'a tank of its contents, the roof risesor descends Such aaroof cannot-.bew-made. to form-a vapor-tight, jointwith thewal-lsl ofgthfi" tank and. at the; same time; be. movable due ,to .ir.-. regularities inthe.walls ofithertankg Ineorder. to make-the floating,roofecover.theJsurface-of the liquid :as nearly as -possibleean. expansiblegjoint.

has been devised to take .up irregulari-tieszin the? walls-of the tank as. a eroofrascendszor descends. Even such an expansible joint-does"not ,contact-. the walls of the tank in a truly-vapor-tightxman ner; and vapor leakage. outward or:air.=leakageinward, .or. both may occur. It is;atasuchl-points; on 'thegroof. of the; tank that: fireiordinarily ;be'-:

gins; Since the entireiroofeoistheztank.zwithrthe:

exception of the ciroular, annular: expansihlei joint: of frelati-vely small. width; disposedqbetweenr: the periphery of the rigid-iroofnndcthezwallswfi' 2' for; fighting}; fires;;ar.ound the floating roof-of,- arfioating roof tank.

Another object: of my invention is to provide an apparatus for the-injection of Y fire-fighting:

foam intozthe vaponspace-of an .expansible'jointi between the floating roof and. the walls of afloating;roof:-.ta-nk.

Still: another object of my'invention is to 'pro-; vide an apparatus .for the fightng of fires around the periphery ofithe floating; roof tank inilwhich foam fire-fightingamateriah can; be a. quickly and effectively:distributed overlthe-surfaee of thesliqe uidi';

Still. other;-obiects,andtadvantages of my-ineventionawill be realizeduporr reading-therfollow ing';disclosurev which,:.. taken with therattached:

drawings, forms a part of this specification.

Figure 1--.of:- the-drawingis-anelevational view,

partly in section-,; of-- an open top storage tank.

having- 5 a heating; roof: and equipped with: thefire-fighting; apparatus of my invention; Figure 2 is a plan view,--in part; of such a floatinggroof. tank... Figure-3 is ah-plan view on anenlarged scale ofaportioniof the-apparatus of my inven-.-

ti'on. Figure '4- is:an elevational view ofthe ape paratusof FigureB. Figure 5 is a view, partly in section'jand partly in; elevation and on anenlarged scale of a-portion of the floating-roof. embodying: mydnventionl.

Referring .nowrto the drawing. and specifically: to- Figure 1, a tank I l is. provided with several. inlet-sand outlet pipevconnections, l2, l3 and 14.. Such pipeconnectionsiare more or less conven-.; tional. apparatusuwith tanks. Tanks which are.

. intended'foriusein' the; storage of petroleumor petroleum-products "frequently contain some .wa ter and it is customary that one of the pipe con nections, -as for example; connection I 3 her-pro viderl for. the removal of thewaterfrom beneath" the toil; Connection I 2.is .vfor inlet and: .outlet of the product stored or-even separateinleti a'ndoute let-connections may be provided; Pipe connection M -passes throughthewal-ls of the tank and is connected to a pipe l5inside theitank, Which:- pipe. is. ordinarily some type of flexible. conduit. and this conduit leads to. the fioa-tingroof-randria usednfor. removalof water. accumulatingwmthe; floating-roof.

.-The?;fioating; mot.v assembly [6 is of .-conven-a tional. construction'and consists of email cham her: l9-bounded bysheet steel. Thebottom sec-'- tion of: the air chamber. I9 :is identified by refer-e ence numeral l8; and-this metal section l8 and" the; horizontally disposed sheet -metal' ll ,form;

periphery j of. '1, thee- I larger portion of the surface of the liquid in the tank. Since the floating roof of course possesses considerable weight, it displaces some liquid, and the liquid rises above the bottom of the air chamber Is as may be seen between the air chamber wall 24 and the wall of the tank H. .The flexible sealing means disposed between the periphery of the floating roof and the wall of the tank consists of the slidable shoe members 20 supported by the support members 23, springs 22 and braces 22a. The top of the shoes 20 are connected with the outer and upper edge of the air chamber IS with a flexible material 2|, such as canvas. This flexible material 2| is intended to flex and yet maintain a tight seal between the top of the shoe members 20 and the outer edge of the floating roof as the roof ascends or descends within the tank.

When the flexible sealing material 21 is new and undamaged, the seal between vapors under the material 2] and the atmosphere is ordinarily effective. With the passage of time, however,

suchsealing material sometimes becomes damaged'and torn or may become rotten or even hard and brittle. Under such conditions, when this material is of an inflammable nature an additional hazard exists. Also, this material is easily ruptured-and when broken or torn in any manner, vapors from the liquid being stored have an opportunity to become mixed with air, thereby forming an explosive mixture. This explosive mixture is then present in the space above the surface of the liquid 40 and below the sealing member 2| and between the side wall 24 of the air chamber l9 and the shoes 20. Thus this portion of the tank is vulnerable to explosion and fire. v

- My invention comprises an apparatus which is adapted for the rapid introduction of the fire fighting foam into this vapor space between the flexible material 2 I, the surface of the liquid 40, the shoes 26 and the side of the roof 24.

' Fire-fighting foam from a source of supply 39. outside of the tank, is passed. through a pipe 4| into a pipe connection 32 in the Wall of the tank at a point near its base. The foam then passes through a flexible conduit 33 to a distributing head 34 which is disposed on the floating roof at a point near the center. This distributing head 34 is shown in detail in Figures 3 and 4 and consists mainly of a vessel 42 having a number of pipe connections 43. To these connections 43 are fastened some conduits 35 and 36. These conduits 35 and 36 are for the purpose of transmitting the fire-fighting foam from the vessel 42 radially to several points within the above-mentioned vapor space. As many pipe connections 43 may be provided in the vessel 42 as desired. In general, for tanks of greater diameter, more of these pipe connections 43 and conduits 35 and 36 are provided. The conduits 35 and the upper portions of the conduits 36 pass through the air chamber H! as pipes 31. To the ends of the pipes 31 are attached some Ts 38. The Ts 38 are so positioned that foam passing through pipe 31 will enter the vapor space in a direction normal to the axis of the pipes 37. In a tank such as illustrated in Figure 1 when eight radial conduits 35 and 36 are used and foam is transmitted in both directions from the ends of each conduit, the foam spreads over the entire surface 40 of the liquid in the vapor space in a very short time. Gne of the important points in fighting a fire, such as an oil fire is to extinguish the fire before the metal parts of the tank have had .an opporthe conduits 36. Such drained material may then be washed with water and removed from the roof through the flexible pipe I5 and passed through pipe 14 for such disposal as desired. Conduit 15 also serves for disposal of rain water. Valved pipes 41a and 34a are provided for drainage of foam and flushing purposes.

On the underside of the roof are some depending members 3| which are intended to act as posts or supports for supporting the floating roof in times when all, or substantially all, of the liquid is pumped from the tank.

In the operation of the apparatus of my invention when a fire occurs around the periphery of the floating roof, it is merely necessary to pump fire-fighting foam from its source 33 through pipe 4|, connection 32, and flexible conduit 33, into the distributing heat 34. From this head the foam radiates through conduits 35 and 35 and is very quickly distributed through the several T members 36. As soon as the entire surface 43 of the liquid is covered with foam, the source of the inflammable vapors is sealed off.

Materials of construction for this foam distributing system may be selected from among those commercially available which are suitable for handling such materials. In general, ordinary steel pipes and sheets are satisfactory. As many conduits 35, 36, and distribution Ts 38 may be used, as are warranted according to the size of the tank. Any type or form of distributing head 34 may be used providing the head is adapted to rapid distribution and flow of fire-fighting foam. Any type of flexible pipe may be used for the pipe 33 providing the flexibility is such that all joints and portions of pipe are tight and fluid proof and adapted to deliver foam to the distributing head regardless of the position of the roof.

The above-described foam distributing apparatus is given for illustrative purposes and should not be regarded as limiting the invention, the scope of which is set forth in the following claims.

Having described our invention, we claim:

1. Apparatus for use in extinguishing fire in storage tanks in which inflammable liquids are stored and having a floating roof, slidable shoes attached to the periphery of said floating roof witha flexible material to form a seal between said floating roof and the vertical wall of the tank andaffording a closed vapor space bounded by the surface of the inflammable liquid, the slid able shoes, said flexible material, and the periphery of said floating roof, comprising a first pipe extending through the wall of the tank, a conduit in said tank having one end attached to said first pipe and. the other end attached to one end of a second pipe extending through said floating roof, said second pipe extending radially above said roof and terminating at a point within said vapor space and means to supply fire extinguishing foam to said first pipe.

2. Apparatus for extinguishing fire in an oil storage tank having a floating roof, slidable metal shoes attached to the periphery of said floating roofwith a flexible materialto formasealbetween said floating roof and the vertical wall of the tank and affording a closed vapor space bounded by the surface of oil, the slidable shoes, th flexible material and the peripher of said floating roof, comprising a first pipe extending through the wall near the base of the tank, a conduit in said tank having one end attached to said first pipe and the other end attached to one end of a distributing head extending through said roof, one end of each of a plurality of distributor pipes connected with said distributing head, said plurality of pipes extending radially toward the wall of the tank and terminating in said vapor space, and means to supply fire extinguishing foam to said first pipe.

3. In the apparatus of claim 2 a pipe T attached to the end of each pipe of said plurality of pipes in said vapor space for distributing firefighting foam over the surface of said oil exposed to said vapor space.

4. An apparatus comprising, in combination, an open top tank for storing inflammable liquid, a floatable roof for covering the surface of said liquid, slidable metal shoes attached to the periphery of said floating roof and joined thereto by a flexible material to form a seal between said floating roof and the vertical wall of said tan: and forming a closed vapor space bounded by the surface of said inflammable liquid, the slidable shoes, said flexible material and the periphery of said floatable roof, a first pipe extending through the wall of said tank at a point near its base, a second pipe extending through said floatable roof and attached to a distributing head mounted on said roof, a conduit connecting said first and second pipes, a plurality of pipes extending radially from said distributing head toward the walls of said tank, a pipe T attached to the end of each of said plurality of pipes and said Ts terminating in said vapor space and so disposed that the axes of the side inlets of said Ts are coincident with the axes of said radially disposed pipes at the point of contact with said Ts, and means for supplying fire extinguishing foam to said first pipe.

5. Apparatus for use in extinguishing fire in storage tanks in which inflammable liquids are stored and having a floating roof, slidable shoes attached to the periphery of said floating roof with a flexible material to form a seal between said floating roof and the vertical wall of the tank and affording a closed vapor space bounded by the surface of the inflammable liquid, the slidable shoes, said flexible material and the periphery of said floating roof comprising in combination, a source of fire fighting foam, a first conduit extending from said source of foam through the Wall of the tank, a conduit means in said tank in fluid communication from said first conduit to a point above the surface of said floating roof, a second conduit in fluid communication with said point and extending therefrom to a point within said vapor space.

6. In combination with a tank having an open top for storing inflammable liquid, a roof adapted to float on the surface of said liquid and disposed in said tank to close the major portion of said open top, a flexible and expansible vapor sealing member secured to the periphery of said roof and biased into vapor sealing relation with the walls of said tank whereby a closed vapor space is formed above said liquid between said sealing member and said roof, a supply of fire extinguishing foam under pressure and a conduit secured to said roof connecting said supply and said vapor space.

' CLAUDE H. TROTTER. ARTHUR W. SWEENEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,770,623 Newmann July 15, 1930 2,079,438 Ellis May 4, 1937

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