AND FIRE SUPPRESSION APPARATUS

BACKGROUND

[0001] Inorganic salts, such as those composed of phosphate anions are known and used to extinguish or retard thermal events, such as fires. For instance, particles of the monoammonium phosphate may be included in a fire extinguisher that projects the material onto the fire to be extinguished. Various types of additives may be combined or added to the particles of monoammonium phosphate to facilitate the use or flow thereof. For instance, additive particles of silica may aid the flow of the material and other types of inorganic salts, such as ammonium sulfate may be added to the mixture.

SUMMARY

[0002] An exemplary fire retardant composition for use in a fire suppression apparatus includes a powdered material having a plurality of substrate particles and flame retardant particles disposed on surfaces of the plurality of substrate particles.

[0003] An example fire suppression apparatus includes a container and a fire retardant material within the container. The fire retardant material includes a powdered material having a plurality of substrate particles and flame retardant particles dispersed on surfaces of the plurality of substrate particles.

[0004] An exemplary method of producing a fire retardant composition for use in a fire suppression apparatus includes depositing flame retardant particles onto surfaces of a plurality of substrate particles of a powdered material.

[0005] The various features and advantages of disclosed examples will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 illustrates a powdered material having a fire retardant composition.

[0007] Figure 2 illustrates a fire suppression apparatus that includes the powdered material illustrated in Figure 1. DETAILED DESCRIPTION

[0008] Figure 1 illustrates selected portions of an example fire retardant powdered material 20 for use in a fire suppression apparatus, such as a fire extinguisher. In this case, the powdered material 20 is of a composition that utilizes a flame retardant material dispersed mainly on the surface of a substrate particle, such as an additive particle. As will be described in further detail, the powdered material 20 thereby utilizes less flame retardant material than prior known compositions and is therefore more efficient in extinguishing a flame.

[0009] In the illustrated example, the powdered material 20 includes a plurality of substrate particles 22 that each includes flame retardant particles 24 disposed on surfaces 26 of the substrate particles 22.

[0010] The following examples will illustrate a few options for selecting the type of flame retardant particles 24 and substrate particles 22. However, it is to be understood that this disclosure is not limited to the examples herein and, given this disclosure, one of ordinary skill in the art will be able to select other types of materials to suit their particular needs. In this case, the substrate particles 22 may be selected among mica, silica, diatomaceous earth, and combinations thereof. That is, all of the substrate particles 22 may be one of the designated types of materials or a mixture of any two or more of these materials. To give examples provide the benefit of having a relatively high surface area for deposition of the frame retardant particles 24. For instance, the substrate particles 22 may have a surface area of around 400 m ² /g or less. The relatively high surface area provides a corresponding greater surface to deposit flame retardant particles 24 that will in turn higher exposure to a flame. In comparison, a greater amount of the flame retardant particles 24 are exposed to the flame than if the flame retardant particles were provided as individual particles of lower surface area rather than deposited onto the substrate particles 22. In this regard, the disclosed arrangement of the powdered material 20 provides a more efficient and effective flame extinguishing property.

[0011] In a further example, the substrate particles 22 may be selected to have an average particle size within a desired range to provide a targeted surface area. For instance, a substrate particle 22 may have an average particle size of up to about 50 micrometers. In a further example, the average particle size may be about 1-20 micrometers. If the substrate particles 22 are mica, an average particle size toward the higher end of the range at approximately 20 micrometers may have a surface area of approximately 5 m ² /g. On the other hand, an average particle size toward the other end of a given range at one micrometer for a particle of silica may have an average surface area of around 350 m ² /g. Although such smaller particles have a greater surface area, there may be other considerations in selecting an appropriate particle size for a particle use such as flow characteristics of the particles. Additionally, for a layered type of substrate such as mica, the flame retardant particles 24 may additionally deposit between the layered sheets of the material and also on the outer surfaces of the material. That is, for any given type of substrate particle 22, the flame retardant particles may be deposited primarily on the outer surfaces or also within pores or interlayer between sheets if the given type of substrate particle 22 includes such features.

[0012] In the above examples, the flame retardant particles may be particles of monoammonium phosphate (NH ₄ H ₂ PO ₄ ). In this case, the monoammonium phosphate may be deposited onto the substrate particles 22 in any of a variety of different techniques. For instances, monoammonium phosphate is soluble in water and may thereby be mixed with water or other type of carrier liquid to form a solution. Other additives may be added to the solution to openly facilitate flow of the fire retardant composition or in part other properties thereto. For instance, silica particles may be added to the composition mixture solution as a flow aid. The substrate particles 22 may then be added to the solution and mixed therewith. Such step that the solution infiltrates any pores in the substrate particles 22 or in the case of a layered material between the sheets. Of course, infiltration of the pores or sheets may depend upon chemical interactions between the solution and the substrate particles 22. The mixture may then be stirred for a desired amount of time, such as 30 minutes before removal of the carrier liquid. As an example, the carrier liquid may be removed by vacuum and/or elevated temperatures. In one example, the carrier liquid is removed through rotary evaporation such that the mixture is continually mixed during removal. In another example technique, the mixture may be spray dried in a known manner to deposit the flame retardant particles 24 onto the surfaces of the substrate particles 22. For instance, the spray drying may include providing two feeds that are blown into a heated vacuum chamber. One of the feeds may be the solution of the carrier liquid and the monoammonium phosphate and any other additives that will be used and other feed may be the substrate particles 22. As the liquid carrier evaporates when blown into the chamber, the remaining monoammonium phosphate deposits onto the substrate particles 22 to thereby form the powdered material 20. In either of the above exemplary techniques, temperatures of around 100-120°C may be used. Of course, the selected temperature may depend upon the type of carrier liquid that is used. [0013] Additional methods of preparation include heating the monoammonium phosphate and the rapidly mixing a substrate and additive while keeping the monoammonium phosphate in the molten state. A further method of preparation includes the high friction mixing of the monoammonium phosphate salt onto to the substrate and additive components. High friction mixing would take advantage of the much lower melting point of the monoammonium phosphate (~190°C) and ideally disperse the phosphate salt onto the substrate and additive particles as described in the other methods of preparation.

[0014] The composition of the flame retardant particle 24 relative to the total combined weight of the flame retardant particles 24 and the substrate particles 22 may be adjusted as desired during the fabrication process. As an example, the composition of the powdered material 20 may include up to about 45 wt.% of the flame retardant particles 24. In further examples, the composition may include 15-40 wt.% of the flame retardant particles 24 or even 20-24 wt.%. Whereas flame retardant such as monoammonium phosphate are commonly used in much higher percentages, the disclosed examples and fabrication techniques allow effective use of lower amounts of the monoammonium phosphate. In some cases, the amount of flame retardant particles 24 and the final composition depends upon the amount used in the solution to make the powdered material 20. For instance, a slightly higher amount relative to weight percent may be required in the solution than is desired in the final composition due to the loss of some of the monoammonium phosphate in the process. In other examples, the amount of monoammonium phosphate in the preparation solution may correspond closely to the amount in the final product. Thus, there may be some variation in the process that may or may not influence the final composition. In one example rotary evaporation of, an amount of about 26 wt.% of the monoammonium phosphate relative to the total combined amount of monoammonium phosphate and substrate particles in the mixture was used to produce a final composition of the powdered material 20 that had approximately 24 wt.% of the flame retardant particles 24. In other techniques, such as spray drying, the process may be more efficient such that the mixture more closely corresponds to the amount of flame retardant particles in the final composition.

[0015] In the above examples, the powdered material 20 may undergo a grinding step after removal of the carrier liquid. For instance, the grinding may break up any agglomerates that formed during the fabrication process. In one example, the powdered material 20 may be ground for a relatively short time such as five minutes to break up any agglomerates and thereby avoid forming other agglomerates that generally broaden the particle size distribution. [0016] Figure 2 illustrates an example fire suppression apparatus 40 that the powdered material 20 may be used within. In this example, the fire suppression apparatus 40 includes a container 42 and the powdered material 20 within the container as a fire retardant material. As described above, the fire retardant material includes the plurality of substrate particles 22 and the flame retardant particles 24 disposed on surfaces of the substrate particles 22. In this case, a release tube 44 extends within the container 42 and includes an opening 46 near the bottom of the container 42. The release tube 44 extends upwards from the end 46 and terminates at a nozzle section 48 for releasing the flame retardant material. In operation, the powdered material 20 flows upwards through the release tube 44 and opening 46 towards the nozzle 48. In this regard, the fire retardant material may be pressurized such that a user may manually open the nozzle 48 to release a discharge or spray of the fire retardant material. It is to be understood that the fire suppression apparatus 40 shown in the illustrated example may also include other features or components and is not limited to the particular arrangement shown. In this regard, the powdered material 20 may be used in other types of fire extinguishing devices or arrangements that are not specifically shown here.

[0017] The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the scope of legal protection given to this invention, which can only be determined by studying the following claims.