US2692649A - Apparatus for extinguishing fires - Google Patents

Description

1954 c. M CREARY APPARATUS FOR EXTINGUISHING FIRES Filed March 3, 1951 Patented Oct. 26, 1954 2,692,649 APPARATUS FOR EXTIN GUIS G FIRES Chester L. McCreary,

to Union Compton, Calif., assignor Oil Company of California, Los Angeles, Califl, a corporation of California.

Application March 3, 1951, Serial No. 213,772

16 Claims.

This invention relates to an apparatus for extinguishing fires and in particular relates to the extinguishing of fires by means of solid fire extinguishing compositions in powdered form. One specific application of the present invention is in the protection of storage tanks and the like containing flammable materials such as organic solvents, gasoline, crude oil, and other such materials.

Numerous fire extinguishing systems are known in which storage tanks or other vessels are provided with piping opening near the top of the chamber and adapted to the delivery of foams onto the burning surface to smother the flames. In most cases such systems are subject to numerous disadvantages, including the problem of corrosion of the piping used to deliver the extinguishing composition. Furthermore, these systems are in most cases at least partly manual in operation and if not operated quickly enough the heat of the fire often collapses the roof and sides of the chamber, thus rendering the piping inoperable for its intended purpose. The contents of the tank also may become too hot to smother the fire safely, 1. e., danger in evolved vapors.

Furthermore, systems for the extinguishing of tank fires require considerable inspection in their upkeep and maintenance. This maintenance is particularly involved to a high degree in those systems which employ solid fire extinguishing compositions since the piping may not be maintained full of the composition because of the dangers of packing and not being flowable when the need arises.

It is therefore to the provision of an improved automatic fire extinguishing system employing the improved types of powdered fire extinguishing compositions that the present invention is directed.

A primary object of this invention is to provide an apparatus for the protection of chambers containing flammable liquids or solids in which a thermally-sensitive distributing element is provided at the outlet employed to deliver the extinguishing composition, the fusion of which member causes the pressuring of a normally low pressure reservoir containing the solid extinguishing composition and delivers this material to the fire.

Another object of this invention is to provide an improved automatic apparatus for delivering solid extinguishing compositions to burning tanks which requires a minimum of maintenance and which apparatus is essentially fast acting thus 2 preventing excessive heating of the contents of the tank.

An additional object is to provide an improved dispersing apparatus for powdered solid fire extinguishing agents.

It is a further object to provide an improved combination apparatus for quenching fires automatically.

Other objects and advantages of the present invention will become apparent to those skilled in the art as the description and illustration thereof proceeds.

Briefly, the present invention comprises an improved combination of a first reservoir or zone containing a non-combustible fluid under pressure communicating through a valved (normally closed) conduit with a second reservoir or zone containing a solid fire extinguishing composition in powdered form. The combination further includes a delivery conduit or zone communicating at its inlet with the second reservoir and provided with at least one outlet positioned adjacent the surface or area to be protected from fires. This delivery conduit may comprise a manifolded system provided with a plurality of outlets in which one or more are positioned in a given tank or storage vessel to be protected. The manifold may further be connected via a plurality of feeder conduits to a plurality of tanks such as those positioned in tank blocks, as in storage of petroleum fluids in tank farms.

The powder dispersing outlet through which the solid fire extinguishing composition is delivered is a particularly improved apparatus hereinafter more fully described and provided with a nozzle capable of directing a stream of suspended solids against a deflection plate or baffle positioned in impinging relationship to the delivered stream. This deflection plate is placed substantially transverse to the stream and is preferably spaced apart from the nozzle opening a distance of between about 0.75 and about 3 deflection plate diameters for best dispersion effects. Thus, as the granular solids are directed into the tank they are deflected by the bafiie in substantially all directions in the plane of the deflection plate, forming a cloud which blankets and extinguishes the flames.

Each nozzle is connected to the manifold by means of a feeder conduit and is further provided with a fusible plug within the nozzle. The operation of the system is such that upon fusing of the plug, the feeder pipes and the manifold are depressured from a predetermined maintained control pressure and the change in mamfold pressure thus causes the opening of the normally closed conduit connecting the h gh pressure fluid reservoir to the reservoir contaming the fire extinguishing composition. The result is that an improved powdered solid fire extinguishing system is attained which may be made automatic in operation and which requires a minimum of maintenance.

The method of operation and the nature of the combination apparatus of the present invention will be more fully understood by reference to the accompanying drawings, in which:

Figure 1 is a schematic flow diagram indicating the connection of the two reservoirs referred to with the tanks or other areas to be protected;

Fi ure 2 is a detailed drawing in cross-section of the dispersing apparatus including the nozzle and deflection plate employed;

Figures 3 and 4 are detailed cross-sectional drawings of modifications of the deflection plate which may be employed in specific instances, and

Figure 5 is an isometric view of the powdered solid dispersing assembly.

Referring now more particularly to Figure 1. the first reservoir of high pressure, non-combustible fluid may comprise a plurality of cylinders It provided with valved outlet [2 connecting them with high pressure fluid manifold M. The cylinders may contain such gases as nitrogen or carbon dioxide but other available noncombustible gases may be employed. A single large volume vessel may also be substituted. The second reservoir comprising solids chamber I6 is provided containing the powdered solid fire extinguishing composition It. Chamber i6 is provided with solids loading inlet 20 provided with shut-off valve 22 and with pressuring fluid inlet pipe 24. The fluid inlet pipe communicates with hi h pressure fluid manifold M and is provided with automatic valve 26 actuated by means of pressure controller 28 as subsequently described. Second reservoir i6 is also provided with powder delivery conduit 30 which connects with delivery manifold 32 in turn provided with individual feeder conduits 34 and 36 to tanks 38 and 40,

respectively. I

The outlets 42 and as of feeder conduits 34 and 36, respectively are provided with the powdered solid dispersing apparatus more particularly described in Figures 2 through 5 below.

The combination system is placed in operation by first charging the solids reservoir l6 with the powdered solid fire extinguishing composition. Shut-off valve 22 is then closed. Control valve 26 is closed and valved lines l2 leading from cylinders l8 into fluid manifold M are opened. Solids chamber 56, outlet conduit 30, delivery manifold 32 and the feeder conduits 34 and 36 are maintained under a low superatmo'spheric control pressure subject to diurnal variations (caused by atmospheric temperature changes) above a predetermined minimum value of between about 0.5 and 50 pounds per square inch gauge andpreferably between about 2 to 20 pounds gau e. Pressure tap 50 is provided in delivery manifold 32' to permit continuous detection of the control pressure present in the manifold and to actuate pressure controller .28 which in turn opens control valve 26 upon decrease of the control pressure to a value substantially below the minimum or at a rapid rate. Thus, when a fire occurs adjacent one of the protected areas such as tanks 38 and 40, the fusible plug in the nozzle at the outlet of any one or more of the feeder conduits opens, causing the rapid loss of control pressure from the feeder conduit and delivery manifold. The pressure indicated at pressure tap 5!! thus drops rapidly (relative to the diurnal variations) to a value well below the minimum value of control pressure, causing pressure controller 23 to open valve 25. The high pressure fluid is thus charged into solids reservoir l6, forming a flufiy suspension of the finely powdered fire extinguishing composition which discharged through outlet conduit 30 and delivery manifold 32 and subsequently through the appropriate feeder conduit which has been opened by the fusion of the fusible plug. A fine suspension of the fire extinguishing composition in the non-combustible fluid is thus discharged into the area to be protected and dispersed in a cloud by the deflection plate positioned adjacent the nozzle.

While in stand-by operation when no fire exists, the delivery manifold and feeder conduits are maintained at a pressure somewhat above the minimum pre-determined control pressure by means of the operation of pressure controller 52 which is actuated in accordance with the pressure indicated at pressure tap 50. Pressure controller 52 operates automatic valve 54 in control conduit 56. Control conduit 56 connects the high pressure manifold [4 with delivery manifold 32 and is provided with throttling valve 58 in series with control valve 54. Thus, if for any reason small leakages occur which tend to allow the diurnal minimum of control pressure to drop below the minimum pre-deterrnined value in the feeder conduits or the delivery manifold, i. e. such as during cold nights, the control pressure indicated by tap 50 decreases and pressure controller 52 operates valve 5 whereby a small bleed stream of non-combustible fluid passes via line 56 through throttling valve 58 into delivery manifold 32 to maintain the control pressure continuously above the pre-determined minimum value.

In the present combination apparatus the delivery outlet of each feeder conduit is sealed by means of the fusible plug thereby preventing corrosion of the feeder conduit or of the inside parts of the nozzle. The fusible plug further seals the system against the discharge of the fluid maintained at the control pressure in the delivery manifold until heat is generated suffcient to melt the plug. The adjustment of throttling valve 58 is such that the flow therethrough is insufficient to maintain the control pressure in the delivery manifold at its minimum preset value. This is easily done by removing one of the nozzles and adjusting valve 58 while measuring the resulting control pressure. When one of the fusible plugs has melted and one nozzle is thereby opened, the pressure falls in the delivery manifold to a value substantially below the control pressure minimum and at a rate much greater than the diurnal variations. Controller 28, which may be actuated either by the decrease in pressure to a value substantially below the minimum control pressure or by the high rate of depressuring, opens valve 25 discharging the fire extinguishing composition through the delivery manifold and the proper feeder conduit to the location of the fire.

With particular reference to tank 38, it is to be noted that the dispersing apparatus includes a distributing plate 60 which is disposed at an angle other than to the axis of the nozzle at outlet 42. This is particularly desirable in tanks in which the dispersing apparatus is disposed noncentrally with respect to the surface or area 62 to be protected. As shown in Figure 1, particularly in combination with tank 40, distributing plate 64 is disposed at a 90 angle to the axis of the nozzle and outlet 4 3 since it is centrally located with respect to surface or area 66 to be protected therein.

In Figure 2 a detailed view in cross-section is shown of the dispersing apparatus positioned at the outlet of each feeder conduit in the combination apparatus of this invention. The distributing apparatus comprises feeder conduit 68 provided at its outlet with nozzle Ill. The nozzle opening is sealed by means of fusible plug 12 and deflection plate 74 is suspended transverse to the outlet of nozzle H1 in impinging relationship to the stream which discharges from the nozzle. Supporting members 76 and 18, which may be welded at one end to the nozzle itself or to the feeder conduit 68, support baffle plate 14 in the described position. In Figure 2 a disc is shown disposed at 90 to the nozzle axis 80 thereby deflecting the discharge stream from the nozzle in substantially all directions in the plane of bafile I4. Desirably, perforations 82 are provided in plate l4 so that at least part of the discharging stream of extinguishing composition is directed downwardly to the surface immediately below.

In Figure 3 a modification of deflection plate Hi is shown in which conical baliie 82 is provided in which the apex 84 thereof is substantially aligned with axis 80 of the nozzle. Such a construction permits discharge of the extinguishing composition cloud in a more downward direction than that permitted by the flat plate Hi shown in Figure 2.

In Figure 4 is shown a third modification of the deflection plate in which plate 86 is shown substantially aligned with axis 80 of the nozzle but inclined at an angle thereto other than 90, as was described in connection with tank 38 in Figure 1. Part of the discharging cloud is deflected to the right as Figure 4 is normally viewed, but most of it is deflected to the left which adapts it to non-central positioning of the distributing apparatus with respect to the surface to be protected. Any of the types of deflection baiiles shown in Figures 2, 3 or 4 are applicable to the installation shown in Figure l in tank iii.

In Figure 5 an isometric drawing of the modification of the dispersing apparatus shown in Figure 2 is shown in which nozzle 99 is directly connected to the outlet of feeder conduit 92. Deflection plate 94 is supported by means of supporting rods 95 connected directly to nozzle 9t. Perforations 98 are indicated in deflection plate 94 for the purpose described.

In the operation of the combination apparatus of this invention the preferred type of fire extinguishing composition is precipitated sodium bicarbonate in finely powdered form and having a mesh size smaller than 50 and preferably smaller than a 100 mesh. However, other solid materials capable of liberating a non-combustible gas such as carbon dioxide upon the application of heat to that material may be used in the apparatus of this invention.

Materials suitable for use as the fusible plug in the nozzle of the distributing apparatus preferably melt below about 300 F. Such materials include the well known low melting alloys such as those low melting compositions given in the table below:

As an example of the application of the present invention to the extinguishing of oil fires, a nozzle was constructed from a A" pipe collar and was provided with A supporting rods in the form of a tripod supporting a 2" perforated disc a distance of 2.75" from the nozzle outlet. The disc was provided with 16 A3" diameter holes and the fusible plug employed was Woods metal melting at 158 F. A 20-foot A" (normal pipe size) feeder conduit was connected to the nozzle at one end and to a solids chamber containing 20 pounds of sodium bicarbonate in finely divided form. The distributing apparatus was positioned approximately 18" above a rectangular tank 3 feet by 9 feet containing a mixture of diesel oil and gasoline. The apparatus was placed in operation, a fire was lighted in the rectangular tank, the plug melted out in about 5 seconds and the fire was completely extinguished in 45 seconds. A complete blanket of sodium bicarbonate powder was established quickly over the entire exposed burning surface, markedly reducing the intensity of the burning immediately.

A particular embodiment of the present invention has been hereinabove described in considerable detail by way of illustration. It should be understood that various other modifications and adaptations thereof may be made by those skilled in this particular art without departing from the spirit and scope of this invention as set forth in the appended claims.

I claim:

1. An apparatus for protection of flammable materials which comprises a first chamber for non-combustible fluid under pressure, a second chamber for powdered solid fire extinguishing composition, a valved connecting conduit between said chambers, a delivery conduit opening at one end into said second chamber and terminating in an outlet adjacent the flammable materials to be protected, said outlet comprising a nozzle sealed by a fusible low melting alloy and a dispersion baiiie in impinging relation to the stream therefrom, means for maintaining said delivery conduit at a predetermined relatively low control pressure, and a pressure sensitive controller connected to said delivery conduit and responsive to said control pressure therein and also connected to and adapted to open said valved connecting conduit in response to a change in said control pressure.

2. An apparatus according to claim 1 wherein said means for maintaining said relatively low control pressure is adapted to maintain said pressure at values between about 0.5 and about 50 pounds per square inch gauge.

3. An apparatus according to claim 1 wherein said means for maintaining said relatively low control pressure is adapted to maintain said 7 pressure at values between about '2 and about 20 pounds per square inch gauge.

4. An apparatus according to claim 1 wherein said non-combustible fluid comprises carbon dioxide.

5. An apparatus according toclaim 1 wherein said non-combustible fluid comprises nitrogen.

6. An apparatus according to claim 1 wherein said powdered solid fire extinguishing composition comprises sodium bicarbonate.

*7. An apparatus for proteetion of flammable materials contained in storage chambers and the like which comprises a fluid chamber containing a non-combustible fluid under pressure, said fluid chamber opening through a connecting conduit provided with a normally closed control valve into a solids chamber containing a powdered solid fire extinguishing agent, a delivery conduit from said solids chamber terminating in a dispersing outlet positioned adjacent the materials to be protected; said outlet provide with a nozzle sealed by a fusible alloy melting below about 300 R, a dispersion plate spaced apart from said nozzle and positioned substantially transverse to and in impinging relation to the discharge stream therefrom; a cohtrol pressure conduit provided with a normally closed valve connecting said fluid chamber with said delivery conduit, a first pressure sensitive valve controller connected to said delivery conduit and responsive to the fluid pressure therein and also conneeted to and adapted to actuate said normally closed valve in said control pressure conduit to maintain a relatively low control pressure within said delivery conduit, and a second pressure sensitive valve controller connected to said delivery conduit and responsive to said control pressure therein and also connected to and adapted to actuate said normally closed control valve in said connecting conduit in response to a decrease in said control pressure.

8. apparatus according to claim 7 wherein said secondpressure sensitive controller is adapted to open the normally closed valve in said connecting conduit in response to a control pressure within said delivery conduit which falls at a rate substantially above that of the normal diurnalpressure variation.

An apparatus according to claim '7 wherein said first pressure sensitive controller is adapted to actuate said valve in said control pressure conduit to maintain a relatively low control pressure above a predetermined minimum value in said delivery conduit.

10. An apparatus according to claim 7 wherein said second pressure sensitive controller is adapted to open the normally closed valve in said connecting conduit upon detection of a pressure within said delivery conduit below said predetermined minimum value whereby high pressure non-combustible fluid is discharged into said solids chamber and a mixture of said fluid and solids isdischarged therefrom through said delivery conduit.-

11'. apparatus for automatically dispersi1 2 powdered solid fire extinguishing compositions -vilitldollt requiring maintenance of high pressure fluids in the eorn'position delivery con-- d'uits which comprises at least one fluid vessel containing a non combustibl'e fluid under a relamay high pressure, a solids vessel containing a powdered solid fire extinguishing composition, a connecting conduit communicating said fluid vessel and said solids vessel, a normally closed second automatic valve in said connecting conduit, at least one delivery conduit extending from saidsolids vessel to an outlet adjacent the desired delivery point, said outlet being provided with a dispersion plate in impinging relation to said 102215 a fusible alloy plug melting be-jlow about 300 F. sealing said nozzle, a control pressure conduit communicating said fluid vessel with said delivery conduit, afir'st automatic valve in said control pressure conduit, a first pressure controller instrument connected to said first automatic valve and to said delivery conduit andbeing responsivet'o pressure within said delivery conduit and adapted to open said first automatic valve and bleed a relatively small flow of said fluid into said delivery conduit to main tain a relatively icy-control pressure therein above apres'et minimum, and a secondpressure controller instrument connected to said normally closed second automatic valve and to said livery conduit and responsive to said relatively low control pressure andadapted to open said normally closed automatic valve in said connecting conduit when said control pressure falls below a preset value which isbelow said preset minimum maintained by said first pressure controller instrument.

12. An apparatus according to claim 11 where in said dispersion plate is spaced between about 0.75 and 3.0 plate diameters from saidnozzle.

13. An apparatus according to claim 11 wherein said dispersion plate is perforated. 7

l4. An apparatusaecordingto claim 11whereins aid dispersion plate is conical and is disposed with its apex adjaeent said nozzle and its axis substantially aligned with the discharge stream.

15. An apparatus according to claim 11 wherein said dispersion plate is disposed at an angle other than with respect to the discharge stream of said nozzle and in impinging relation thereto. v u u u I 16 Anapparatus according to claim 11 wherein said dispersion piate is supported from said nozzle.

References Cited in the file of this patent UNITED STATES I ATENTS Number v Name Date 254,253 Ashcroft Feb. 28, 1882 server Morich July 8, 1884' 1,592,346 Erwin July 1?, 92 2,473,349 snowden June 14, 1949' 2,519,350 cahusac Aug. 22', 1950' 2,559,634 Keefe, Jr. a a1. July 10', 1951

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