Title:
GRATE ASSEMBLY FOR SUPPORTING COMBUSTIBLE WOOD PELLETS
Kind Code:
A1


Abstract:
A grate assembly is provided for at least partially supporting a pile of a plurality of combustible wood pellets. The grate assembly includes a plurality of elongate members positioned to at least partially support the pile of wood pellets. Each of the members has a body with a passage extending through the length of the body and a plurality of transverse holes in communication with the passage to permit movement of combustion gases through the pile during combustion of the wood pellets. The members are spaced apart from each other in a predetermined arrangement to permit movement of the combustion gases through the pile during combustion of the wood pellets. Also, the predetermined arrangement has at least two layers positioned adjacent to each other in a stacked relationship. Each layer has a plurality of members positioned transverse to the members of each layer adjacent thereto.



Inventors:
Palmer, Brad (London, CA)
Application Number:
12/411545
Publication Date:
10/01/2009
Filing Date:
03/26/2009
Primary Class:
International Classes:
F23H13/00
View Patent Images:
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Primary Examiner:
MASHRUWALA, NIKHIL P
Attorney, Agent or Firm:
GOWLING WLG (CANADA) LLP (KITCHENER, ON, CA)
Claims:
I claim:

1. A grate assembly for at least partially supporting a pile of a plurality of combustible wood pellets, the grate assembly comprising: a plurality of elongate members positioned to at least partially support the pile of wood pellets; each said member comprising a body with a passage therethrough and a plurality of transverse holes in communication with the passage to permit movement of combustion gases through the pile during combustion of the wood pellets; the members being spaced apart from each other in a predetermined arrangement to permit movement of the combustion gases through the pile during combustion of the wood pellets; and said predetermined arrangement comprising at least two layers positioned adjacent to each other in a stacked relationship, each said layer comprising a plurality of said members positioned transverse to said members of said adjacent layer.

2. A grate assembly according to claim 1 in which the body of each said member comprises at least two planar segments connected at an apex thereof.

3. A grate assembly according to claim 2 in which each said member is positioned with the apex thereof oriented upwardly.

4. A grate assembly according to claim 2 in which each said layer is affixed to each said adjacent layer at at least one contact point.

5. A grate assembly according to claim 4 in which each said layer is affixed to each said adjacent layer by welding.

6. A grate assembly according to claim 2 in which the grate assembly is integrally formed.

Description:

This application claims the benefit of U.S. Provisional Application No. 61/064,769, filed on Mar. 26, 2008.

BACKGROUND OF THE INVENTION

Wood pellets, made of compacted sawdust and wood chips, are commonly used as fuel in various burner and/or stove devices. The pellets are generally cylindrical or round and relatively small (e.g., between about ¼ and ½ inches long, and about ¼ inch in diameter). The pellets typically have water content of less than about 10 per cent. During the formation of the pellets under pressure, lignin in the sawdust and wood chips plastifies to a limited extent, and the lignin serves to hold the pellet materials together. With increases in the costs of various fossil fuels, wood pellets are a viable heat energy source, whether supplementary or otherwise.

Because the wood pellets are relatively small, a large number is required in order to result in a substantial fire. Pellet stoves or burners are known in which the pellets are fed (typically by an auger) into a burner portion thereof from a hopper. The user puts a relatively large amount of pellets into the hopper, and the auger conveys the pellets to the burner portion from the hopper. The burner portion in such a stove is designed solely to burn pellets, and may include a substantially horizontal plate with holes therein. The pellet stove typically also includes a fan positioned below the plate, for blowing air upwardly at the plate and, to an extent, through the holes. Because of this forced circulation of air in the burner portion, the pellets positioned on the plate are relatively completely burned.

Many people would like to use a traditional fireplace that they already own instead of expending a significant expense in purchasing a pellet stove or burner. In a traditional fireplace or wood-burning stove, however, the combustion of a pile of wood pellets tends to be incomplete at best. The incomplete combustion results from poor circulation of air throughout the pile.

SUMMARY OF THE INVENTION

For the foregoing reasons, there is a need for a grate assembly adapted to permit the movement of combustion gases through a pile of wood pellets.

In its broad aspect, the invention provides a grate assembly for at least partially supporting a pile of a plurality of combustible wood pellets, the grate assembly comprises: a plurality of elongate members positioned to at least partially support the pile of wood pellets; each member comprises a body with a passage and a plurality of transverse holes in communication with the passage to permit movement of combustion gases through the pile during combustion of the wood pellets; the members are spaced apart from each other in a predetermined arrangement to permit movement of the combustion gases through the pile during combustion of the wood pellets; and the predetermined arrangement comprises at least two layers positioned adjacent to each other in a stacked relationship, each layer comprises a plurality of members positioned transverse to the members of said adjacent layer.

In another aspect of the present invention, the body of each member comprises at least two planar segments connected at an apex.

In a further aspect of the present invention, each member is positioned with its apex oriented upwardly.

In another aspect of the present invention, each layer is affixed to each adjacent layer at a minimum of one contact point.

In a further aspect of the present invention, each layer is affixed to each adjacent layer by welding.

In yet another aspect of the present invention, the grate assembly is integrally formed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood with reference to the attached drawings, in which:

FIG. 1 is a side plan view of the body of the device used in the system of the present invention.

FIG. 2 is an end view of the device showing the apex of the body of the present invention.

FIG. 2a is a cross-sectional view of the body illustrating an embodiment of the present invention.

FIG. 2b is a cross-sectional view of an embodiment of the present invention showing the hinge.

FIG. 3 is a side profile view of an embodiment of the system showing bodies of the devices used in formation.

FIG. 4 is a perspective view of an embodiment of the system of the present invention illustrating application of a first fastening member device in a horizontal position.

FIG. 5 is a side profile view of an embodiment of the present invention showing a system of bodies in a predetermined order with fastening members/devices of adjoining bodies.

FIGS. 6 and 6a are cross-sectional views of embodiments of the present invention.

FIG. 7 is a side plan view of an embodiment of the present invention showing a system of numerous bodies releasably attached in a horizontal formation.

FIG. 8 is a perspective view of an embodiment illustrating an alternative form of the body for use in the system of the present invention.

FIG. 9 is a perspective view of a one-piece formation of bodies for use in the system of the present invention.

FIG. 10 is a perspective view of an embodiment of the present invention illustrating a cross-sectional view of the container with apertures in line with the apertures of the stacked bodies therethrough.

FIG. 11 is an exploded cross-sectional view of an embodiment of the present invention illustrating movement of a combustible or combusted gas throughout the system.

DETAILED DESCRIPTION

Although other applications may be envisioned for the present invention, the application of the present invention is particularly advantageous for efficiently burning wood pellets. It will be appreciated by one skilled in the art that the present invention may also be used to burn pellets made of other biomaterials such as corn, switchgrass, or organic waste. Accordingly, without intending to limit the present invention to the embodiments described herein, the invention will be described below in further detail having regard to the system and in particular the varied assortment and arrangement of devices used in that system as shown in FIGS. 1 to 11.

Reference is first made to FIGS. 1-5, and 10 to describe an embodiment of a grate assembly la for at least partially supporting a pile of wood pellets 11 (shown in FIG. 11). In one embodiment, the grate assembly la includes a plurality of elongate members 1 positioned to partially support a pile of wood pellets 11. Each of the members 1 has a body 14 that defines a passage 12 extending through the longitudinal extent of the body 14. The body 14 also includes a plurality of transverse holes 3 that are in communication with the passage 12 to permit movement of combustion gases through the pile during combustion of the wood pellets 11. The members 1 are spaced apart from each other in a predetermined arrangement to permit movement of the combustion gases through the pile of wood pellets 11. The predetermined arrangement includes at least two layers 16 positioned adjacent to each other in a stacked relationship. Each of the layers 16 has a plurality of members 1 positioned transverse to the members 1 of each adjacent layer 16.

Referring to FIG. 1, the member 1 used in the grate assembly of the present invention will primarily be described in conjunction with a further member 1 suitable for arranging in a predetermined fashion to fit an area and type of use. It should be understood, however, that the member 1 and body 14 thereof can be utilized in conjunction with a variety of other types and shapes of devices used as cookers/burners or in other areas used for cooking or preheating, igniting and burning the fuel, in particular wood pellets. For example, the device and the embodiments thereof can be utilized together for temporary or permanent fixtures with or without a surrounding container level on the ground level or raised partly from the ground level. In addition, embodiments of the present invention will be primarily described in conjunction with releasable securing devices for adjoining other adjacent bodies in a predetermined arrangement.

FIG. 1 shows an embodiment of the present invention providing a member 1 of a predetermined size and shape. The member 1 has a body 14 being made of a material having a high thermal conductivity. For example, body 14 can be made of metal/ceramics including but not limited to metal carbides, nitrides and borides. Preferably, the body 14 may be made of steel, stainless steel, iron or combinations thereof and is of a shape and size fitting for directional movement of wood pellets over and around the member 1 or an arrangement 1a as shown in FIG. 3. The body 14 of member 1 is dimensioned in accordance with the end-user's requirements and as such the dimensions can vary extensively. Accordingly, the body 14 can have a cross-sectional view of an inverted-V-shape, a V-shape or combinations thereof having a hinged 5 apex 2 or a fixed apex 2 defining a member 1 length, height and width of a dimension fitting for the purpose intended for industrial or residential use thereof. Preferably, the member 1 dimension can be of a size ranging from about 15 cm to about 120 cm, having a width of from about 0.25 cm to about 3.0 cm. The shape of the body 14 can optionally be round, square, triangular or combinations thereof dimensioned to define apertures 3 or 3a of a fixed or varied size. Preferably, the body 14 defines apertures 3 or 3a along the length of an apex 2 and along a planar segment 4 of body 14, the planar segment 4 can be varied in length ranging depending on the size and number of apertures 3 defined therein or of a length greater or lesser from one end of the planar segment 4 to the other end of the same or adjoining member 1 thereon. Apertures 3 and 3a are dimensioned for directing therethrough a variety of combustion gases (shown as X in FIG. 11), for example, the constituent gases of air such as oxygen, gases formed during combustion such as carbon dioxide and nitrogen, and any other gases that may be present in the vicinity of member 1. Apertures 3 and 3a are also adapted to receive a primary securement-device 7 or a secondary securement-device 7a as shown in FIGS. 4 and 5. Apertures 3 are varied in size and shape to accommodate a style or function of member 1 used for different fuels, more preferably wood pellets 11 as shown in FIG. 11.

FIGS. 2a and 2b depict a cross-sectional view of the body 14 of member 1 as depicted by the A-A′ line going through the aperture 3 in FIG. 1. FIG. 2a shows the aperture whereas FIG. 2b shows the aperture and a hinge 5 used for moveable adjustment of at least one planar segment 4 about the apex 2 for varying the shape of the body 14 to accommodate a predetermined use in a chosen area of combustion or for adapting the member 1 to be used with a different fuel thereof, the varied angle of the member 1 being releasably secured by incorporating a primary securement-device 7 therein. The angle of variation can range from about 10 degrees to about 175 degrees about the apex 2 thereof. FIG. 4 depicts a further embodiment of the present invention providing an arrangement 1a with both the primary securement-device 7 and secondary securement-device 7a engaging several members 1 therethrough. The primary securement-device 7 has a head 6 for operably engagement by the end-user, the head 6 defining dimensioned receiving apertures (not shown) as used with implements known by those skilled in the art.

FIGS. 5 and 6 depict the primary securement-device 7 engaging at least one member 1 of the arrangement 1a, having an elongate body with a proximal end 6 and a distal end 8 thereof. In FIG. 5 an embodiment of the present invention provides the distal end 8 of the primary securement-device 7 to engage the apex 3 of the member 1 as opposed to engaging the aperture 3 of the apex 2 therethrough. Actuation of the proximal end 6 of the primary securement-device 7, having a lesser length, forces downward the distal end 8 of the primary securement device 7 onto the apex 2 of the member 1 thereby engaging and releasably securing the adjacent members 1 together. The secondary securement-device 7a as depicted in FIGS. 4 and 6a provide a further embodiment of the present invention in which the securement device 7a being of a length greater than the length of the member 1 is positioned in and through the apertures 3 of at least one member 1 for releasable securement of the members 1 or for ease of movement of the arrangement 1a in or out of the area of use. Both the primary securement-device 7 and the secondary securement-device 7a are made of a material having a high thermal conductivity, preferably stainless steel, iron or both.

Accordingly, during use the elongate bodies of the securement-devices 7 and 7a expand in the apertures 3 thereby expanding within the apertures 3 and further securing the members 1 thereof. In a preferred embodiment of the present invention the proximal end 6 of the secondary securement-device 7a may have a handle means (not shown) in the form of a loop, hook, grip or combinations thereof to be engaged by the end-user for removing the arrangement out or in of the area of combustion, for instance, in case of an emergency or cleaning. FIG. 7, depicts a further embodiment of the present invention providing several members 1 in a horizontal alignment on top of one another allowing for slidable adjustment of the member 1 within the next member 1 to accommodate an area of use, the length being fixed by the primary securement-device 7 in the arrangement 1b of the system. Accordingly, FIG. 8, depicts an embodiment of the present invention by providing a variation on the shape of the body 14 of the member 1 in which the body 14 is substantially curved. Several substantially curved members 1 can be arranged together to fit a particular dimension of an area of use or for the type of fuel used or both.

FIG. 9 provides an alternative embodiment of the present invention providing a single one-piece molded member 1 having a predetermined size and structure similar to the member 1 of arrangement 1a. The single one-piece molded body 14 is a ready-to-use arrangement 1c alone or with a further arrangement selected from 1c, 1b, 1a or combinations thereof, the arrangements being either releasably secured thereto or positioned on top of each other without the use of a securement device 7, or 7a in a chosen area. FIG. 10 depicts the use of arrangements 1a, 1b, 1c, 1d or combinations thereof surrounded by a wall 10 dimensioned to adjoin to or be in a close proximity to at least one member 1 of the aforesaid arrangements of said members 1. A preferred embodiment of the present invention also provides the wall 10 forming a bottom portion thereof for containing and supporting the chosen arrangement. The wall 10 has a height greater than the height of the arrangement, the wall 10 having apertures 3a therein for alignment with an aperture 3 of at least one member 1 in a chosen arrangement. In a preferred embodiment of the present invention the aperture 3a can be in a direct alignment with the aperture 3 of the member 1 for direct transfer of combustion gases throughout the system thereof.

According to various embodiments of the present invention the member 1 can be in an arrangement as depicted in FIG. 11, where the member 1 is in an inverted position on top of an upright member 1 surrounding as depicted herein wood pellets 11. In a preferred embodiment of the present invention the arrangement of members 1 can be interchanged to effect a better burn rate of wood pellets 11 within the system, accordingly, FIG. 11 shows the movement of combustion gases X throughout one such arrangement Id indicating the collection of combustion gases X within the underside of the apex 3 of member 1 thereby increasing the movement of combustion gases X throughout the wood pellets 11 of the grate assembly for cooking or preheating, igniting and burning thereof. In a preferred embodiment of the present invention the bottom part of the wall 10 can be raised up off a ground level by supporting an underside of the wall 10 with a supporting means (not shown), the supporting means can be varied and regulated to effect a desired angle of elevation. The system of the present invention provides the means for transferring heat and combustion gases throughout the wood pellets 11, that can optionally cover the entire arrangement of members 1, to effect a more efficient cooking of the wood pellets 11 and to ignite the combustion gases X for essentially producing a higher temperature from which the wood pellets 11 are burnt and continuously cooked or preheated thereby heating the system at a constant rate. Embodiments of the present invention provide a variety of applications of the system to be used as inserts in areas of combustion including those areas found in residential and industrial settings wherein for example wood stoves, fire places, cookers, furnaces would be used for applying the economical and effective system provided by the present invention.

It will be appreciated by those skilled in the art that the invention can take many forms, and that such forms are within the scope of the invention as described above. The foregoing descriptions are exemplary, and their scope should not be limited to the preferred versions provided therein.