Biodegradable SAP-containing pellets applicable to vegetation for fire protection and suppression

Abstract

A fire-retardant material comprises a plurality of particles, each having an SAP core surrounded by a fibrous layer to which an outer attachment layer is anchored. When applied to vegetation from an aircraft or ground vehicle, the attachment layer maintains the particle in contact with the vegetation. Concurrent or subsequent application of water hydrates the SAP, which is held proximate the vegetation and retards the fire. The SAP, fibrous layer, and/or attachment layer can be biodegradable. The fibrous layer can comprise coir. The attachment layer can comprise one or more naturally occurring plant materials, such as seed pods having an adhesive attachment feature and/or mechanical attachment features such as spikes or hooks. The disclosed fire-retardant material can be applied to mitigate an active, uncontrolled fire, or to vegetation on either side of a central region to contain an intentional fire within the central region, and thereby create a firebreak.

Claims

1. A fire-retardant mixture configured to suppress a fire and/or protect vegetation against an impending fire, the fire-retardant mixture comprising, a plurality of pellets, each of the pellets comprising: a central core containing a plurality of superabsorbent polymer (SAP) particles; a water permeable fibrous shell layer surrounding and containing the central core; and a water permeable attachment layer surrounding and attached to an outer surface of the fibrous layer, the attachment layer comprising at least one of a mechanical attachment feature and an adhesive attachment feature; the pellets being separated and detached from one another in the fire-retardant mixture; each of the pellets being substantially globular in shape; the pellets, when scattered onto vegetation from an aircraft, spread apart from one another, and separately and independently impact the vegetation and adhere thereto.

2. The fire-retardant mixture of claim 1, wherein the SAP is a biodegradable SAP.

3. The fire-retardant mixture of claim 1, wherein the fibrous layer is a biodegradable layer.

4. The fire-retardant mixture of claim 1, wherein the fibrous layer comprises coir.

5. The fire-retardant mixture of claim 1, wherein the fibrous layer comprises woven fibers.

6. The fire-retardant mixture of claim 1, wherein the fibrous layer comprises matted fibers.

7. The fire-retardant mixture of claim 1, wherein the attachment layer comprises at least one of hooks, spikes, and sap.

8. The fire-retardant mixture of claim 1, wherein the attachment layer comprises a naturally occurring plant fire-retardant material.

9. The fire-retardant mixture of claim 8, wherein the attachment layer comprises at least one of sand, bark, evergreen needles, cleavers, goosegrass, tick treefoil, stickseeds, Aparine, and burdock.

10. The fire-retardant mixture of claim 1, wherein each of the pellets is configured such that upon hydration, the SAP particles swell and becomes gel-like, the hydrated SAP particles thereby extending through the fibrous layer and the attachment layer and at least partially encapsulating the fibrous and attachment layers.

11. A method of protecting vegetation against an impending fire, the method comprising: applying the fire-retardant mixture of claim 1 to the vegetation, at least some of the pellets being thereby adhered by their attachment layers directly to the vegetation; and applying water to the vegetation, thereby hydrating the SAP particles of the pellets.

12. The method of claim 11, wherein applying the fire-retardant mixture comprises dropping the fire-retardant mixture from an aircraft.

13. The method of claim 11, wherein applying the fire-retardant mixture comprises applying the fire-retardant mixture from a ground vehicle.

14. The method of claim 11, wherein applying the water comprises dropping the water from an aircraft.

15. The method of claim 11, wherein applying the water to the vegetation comprises applying the water from a ground vehicle.

16. The method of claim 11, wherein applying the water to the vegetation comprises applying the water to the vegetation concurrently with applying the fire-retardant mixture to the vegetation.

17. The method of claim 11, wherein applying the water to the vegetation comprises applying the water to the vegetation subsequent to applying the fire-retardant mixture to the vegetation.

18. The method of claim 11, further comprising repeating the step of applying the water to the vegetation when the SAP becomes dehydrated.

19. The method of claim 11, wherein the impending fire is an active and uncontrolled fire.

20. The method of claim 11, wherein the method comprises applying the fire-retardant mixture and the water to boundary regions of the vegetation on either side of a central region, and then intentionally setting fire to the vegetation within the central region, thereby confining the fire to the central region until the vegetation therein has been consumed, and the central region has been transformed into a firebreak.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1A illustrates application of water to an active fire according to the prior art;

(2) FIG. 1B illustrates application of water according to the prior art to vegetation that is threatened by an approaching fire;

(3) FIG. 2 is a cross-sectional view of a fire-retardant particle according to an embodiment of the first general aspect of the present invention;

(4) FIG. 3 illustrates direct attachment of the particles of FIG. 2 to vegetation that is threatened by an approaching fire, according to an embodiment of the present invention;

(5) FIG. 4 illustrates aerial application of the disclosed particles to fire-threatened vegetation, followed by aerial application thereto of water, according to a method embodiment of the first general aspect of the present invention;

(6) FIG. 5 illustrates a particle attached to vegetation after hydration of the SAP according to an embodiment of the first general aspect of the present invention;

(7) FIG. 6 illustrates simultaneous spraying of a fiber slurry and SAP power from separate nozzles in an overlapping pattern according to an embodiment of the second general aspect of the present invention; and

(8) FIG. 7 illustrates attachment to vegetation of the fibrous material and incorporated hydrated slurry according to an embodiment of the second general aspect of the invention.

DETAILED DESCRIPTION

(9) The present invention is a fire-retardant material and method that can be used to suppress an active fire in a forest or other wilderness area and prepare vegetation to resist an approaching fire without damaging the environment.

(10) In a first general aspect of the invention, the disclosed fire-retardant material comprises pellets that can be dropped in large numbers onto vegetation that is burning or is threatened by an approaching fire 110. With reference to FIG. 2, each pellet 208 comprises a core 200 containing a super-absorbent polymer (SAP), which is surrounded and contained by a fibrous layer 202, such as a layer of coir. In the illustrated embodiment, the fibrous layer 202 is woven to form a shape that surrounds and contains the SAP core 200. In various embodiments, the SAP 200 and/or the fibrous layer 202 are biodegradable.

(11) A layer of fire-resistant attachment material 204 is fixed to an outer surface of the fibrous layer 202. In various embodiments, the attachment layer 204 is an ecologically friendly layer, for example comprising naturally occurring sand and/or plant material such as one or more of bark, tree sap, evergreen needles, cleavers, goosegrass, tick treefoil, stickseeds, Aparine, and/or burdock, among others.

(12) The attachment layer 204 is characterized by a natural tendency to adhere mechanically and/or adhesively to other objects with which it comes in contact. For example, the attachment layer can comprise seed pods having minute quantities of a sap-like adhesive, spines 206, and/or hook-like structures which enable the seed pods to become attached to passing animals and to thereby spread outward from the original plant. Due to its adhering properties, the attachment layer 204 is fixed to the biodegradable fiber layer 202, and thereby anchored to the SAP core 200.

(13) With reference to FIG. 3, upon being applied to burning or fire-threatened vegetation 300, the attachment layer 204 anchors the particles 208 to the leaves, branches, stems, etc. 300 upon which the particles 208 fall, and ensures that the SAP cores 200 remain proximate the vegetation 300.

(14) With reference to FIG. 4, a method embodiment of the first general aspect of the present invention comprises dropping the disclosed particles 208 in large numbers onto threatened vegetation 106, for example from a nearby ground vehicle, or by an aircraft 400. Subsequently or simultaneously, water 102 is dropped onto the same area of the vegetation 106, thereby hydrating the SAP cores 200 of the particles 208. If necessary, as the fire causes the SAP 200 to dehydrate, the SAP 200 can be rehydrated by dropping additional water 102 onto the vegetation 106.

(15) In embodiments, SAP 200 encapsulated in a fibrous layer 202 is sprayed from the vehicle or aircraft 400, while the attachment material 204 is simultaneously sprayed from a separate nozzle in an overlapping pattern. so that the attachment material 204 is caused to adhere to the fibrous layer 202 subsequently to being sprayed. This approach helps to minimize any tendency for the pellets 208 to adhere to each other, and distributes the pellets 208 more evenly onto the vegetation.

(16) With reference to FIG. 5, the SAP cores 200 of the particles 208 undergo significant volumetric expansion as they absorb the applied water, and are converted into gel-like materials. In embodiments, due to the relatively open weave or mat structure of the fibrous layer 202, the gel-like hydrated SAP 200 suffuses through the fibrous layer 202 and attachment layer 204 as it expands, while remaining in contact with the fibrous 202 and attachment 204 layers, and proximate to, or in contact with, the vegetation 300 to which the particle 208 is attached.

(17) According to a second general aspect of the present invention, with reference to FIG. 6, the fibrous material 600 is provided in small pieces or loosely associated bundles of fiber, and water 102 is added to the fiber 600 to create a fiber slurry 610. SAP 606 is added to the slurry 610, which is hydrated by the water 102 and incorporates naturally into the fiber 600.

(18) In some embodiments, the SAP 606 is added to the slurry 610 before the slurry is sprayed onto the vegetation. In other embodiments, as illustrated in FIG. 6, the fiber slurry 610 without SAP 606 is sprayed from a first nozzle 604 onto the vegetation 300, while simultaneously applying the SAP 606 in an overlapping pattern, for example by spraying it through a second nozzle 608, so that the SAP 606 is hydrated and incorporated with the fibrous material 600 within the overlapping spray pattern before it reaches the vegetation 300. In various embodiments, the SAP is provided as a powder.

(19) In embodiments, sand 602 is included in the slurry 610, thereby further enhancing the attachment of the fibrous material 600 to the vegetation 300. In similar embodiments, an attachment material such as tree sap, evergreen needles, etc. is included in the slurry, or is sprayed separately into the overlapping pattern, so that after the components have been sprayed, the attachment material contacts and adheres to the fibrous material 600, and then attaches the fibrous material 600 with its incorporated, hydrated SAP 200 to the vegetation 300.

(20) With reference to FIG. 7, upon impacting the vegetation 300, the wet fiber 600 tends to stick to the vegetation 300, while the hydrated SAP 200 remains entangled with the fiber 600, and is thereby maintained proximate the vegetation 300.

(21) As a result of pre-applying the disclosed pellets 208 or slurry 610 to the vegetation 106, 300, in comparison with merely dropping the water 102 onto untreated vegetation 106, 300, a much larger fraction of the applied water 102 is maintained in intimate proximity with the endangered vegetation 106, 300, and the progress of the fire 110 is retarded with enhanced efficiency.

(22) In addition to fighting uncontrolled fires 110, embodiments of the present invention are applicable to containing and directing intentional, controlled fires. For example, if a firebreak is to be created in a wilderness area, the vegetation on either side of the planned firebreak can be treated with the disclosed particles 208 and water 102, or SAP slurry 610, after which the vegetation within the planned firebreak can be intentionally burned to form a barrier region substantially devoid of fuel that might otherwise feed a future fire 110.

(23) The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. Each and every page of this submission, and all contents thereon, however characterized, identified, or numbered, is considered a substantive part of this application for all purposes, irrespective of form or placement within the application. This specification is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of this disclosure.

(24) Although the present application is shown in a limited number of forms, the scope of the disclosure is not limited to just these forms, but is amenable to various changes and modifications. The present application does not explicitly recite all possible combinations of features that fall within the scope of the disclosure. The features disclosed herein for the various embodiments can generally be interchanged and combined into any combinations that are not self-contradictory without departing from the scope of the disclosure. In particular, the limitations presented in dependent claims below can be combined with their corresponding independent claims in any number and in any order without departing from the scope of this disclosure, unless the dependent claims are logically incompatible with each other.