The invention relates to a manifold assembly for a firebox and to a method of assembly. The invention is directed particularly but not solely towards a manifold assembly for a firebox for a wood burner.

Background of Invention

Typically fireboxes are enclosures where a fire burns ie where incoming air enables combustion to occur to produce heat. As combustion requires air there is a need to control and direct the incoming air. Existing fireboxes have incoming air open to atmosphere for a major portion of combustion at the base and air for the top of the firebox to assist in secondary combustion. However though this in-coming air can be said to be used for two different areas in a firebox, it is not able to be controlled or directed. Any fire can have the following sequence/stages of events such as:

-the cold start or re-stoke stage

-fire accelerates with combustion/heat increasing

-fire reaches maximum combustion/heat

-charcoal stage as combustion reduces but still heating

-fire de-accelerates with both combustion and heat reducing

Each stage of any fire in known fireboxes is never completely controlled and so contribute to the problems of poor burning rates and wastage of fuel. As existing fireboxes have vents or chimneys which are open to the air there is always a negative pressure or sucking action to draw air in and through the firebox. This passing air is difficult to control and tends to get faster and faster, with various attempts to use dampers which have proved to be difficult to use and adjust. This in turn causes problems in swapping or pulsing of air during any burning in a firebox which has a detrimental affect on the rate of burning and heat produced. Therefore existing fireboxes do not burn efficiently burning too quickly producing too much ufrburnt fuel and polluted air. Traditionally the aim of current firebox use, has been to reduce the likelihood of a fire going out by introducing as much air as possible to cause the fire to burn consistently and quickly which tends to produce too much heat using too much fuel. This type of use creates the need of current users to then try to dampen it but keep it burning but there is no control of the rate of burning and how efficient the burning is. This inefficient burning causes high running costs, uses alot of fuel and causes unnecessary pollution directly contributing to the greenhouse effect. Many communities and regulatory bodies are demanding cleaner air and some responsibility for causing the problem in the first place.

In this specification unless the contrary is expressly stated, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge; or known to be relevant to an attempt to solve any problem with which this specification is concerned. Object of the Invention

It is an object of the invention to provide an improved manifold assembly and to a method of assembly that ameliorates some of the disadvantages and limitations of the known art or at least provide the public with a useful choice. Summary of Invention

In a first aspect the invention resides in a manifold assembly for managing and controlling air flow for a firebox which is adapted to burn or combust fuel to provide heat whereby particulates form above the fuel during combustion, the firebox being an enclosed housing apparatus with fuel there within defining in use a front part where a door is located or in front of the fuel, a back part is defined as being behind the fuel, above is said to be above the fuel, and below is below the fuel, the manifold assembly including a manifold body having a hollow interior with walls forming an internal pathway for in coming air, the manifold body having entry means for air, and exit means for the air flow wherein the entry means include air separating means whereby the manifold assembly when in use, is adapted to control the air flow into a firebox such that air is able to be supplied and directed to a lower portion of the firebox in at least a first or primary ducting air passageway to enable the fuel to burn or combust or air is able to be directed in a, at least a second or secondary ducting air passageway to a location above the fuel at an upper portion of the firebox, to allow the particulates to burn more efficiently wherein the manifold body includes at least one air separator means located within the internal pathway closer to the inlet than to the outlet whereby air that enters the manifold body is split or divided to then be directed through separate air flow paths to at least the lower or the upper portions of the firebox.

Preferably the shaped portion includes a lower body portion fluidly connected to side upright body portions and the side upright body portions also being fluidly connected to upper body portions.

Preferably, the entry means comprise first and second elongate hollow walled portions forming pathways for the air, such that each entry means have an open entry end and distal end wherein the air separating means is located proximate to the distal end of the entry means within the manifold body wherein there is at least one primary separator adapted to direct air to the lower portion of the firebox and at least one secondary separator adapted to direct air to an upper portion of the firebox.

Preferably, the primary and secondary separator each comprise at least one planar member protruding and fixed to a wall of the manifold body wherein the planar member is oriented parallel to the walls of the entry means and perpendicular to the air flow, to cause the incoming air flow to be split as required.

Preferably the entry means includes an entry aperture located in combination with each separator so that one entry means located at the front of the firebox is able to split the air to back and front with the front being directed to a lower portion and optionally to an upper portion of the inside of the firebox, and another entry means located towards the rear of the firebox whereby the air is split to go to the sides and upwards (to anywhere) and to _^ the back to also go anywhere as required.

Preferably each separator is positioned across an entry aperture in the manifold body where the primary separator is oriented perpendicular to the secondary separator. Preferably, the first or primary separator is able to separate or direct air through primary ducting to the fuel at a lower end of the firebox whereby one air flow is directed to the back of the fuel and the other to the front of the fuel at an upper end of the firebox wherein the flow directed to the back is more than the air flow to the front.

Preferably, the secondary separator is able to separate or direct air through side upright secondary ducting to an upper part of the firebox from at least one side which can be directed to an elongate tubular space in the upper part of the firebox to cause air to be directed to a throat space between the fuel and door, and to an upper part of the firebox door to keep the door clear for viewing.

Preferably, the entry means each include an air control means comprising a movable planar member which is shaped and dimensioned to move within the entry tubular portion to either block or restrict any incoming air according to the air required for combustion anywhere in the firebox.

Preferably, the movable planar member of the air control means is in the form of a disc mounted in a cavity wherein each disc comprises a different weight to the other wherein the first and second planar members are slidably mounted on a central pole with the cavity of the entry portion and can only move from a lower position to a higher position as governed by stop means.

Preferably the secondary ducting can includes a feed via a horizontal ducting formed in to two pathways along the top front of the door inside the firebox which can be feed either from the rear or the front of the firebox or manifold assembly, so that secondary air can be fed downwardly towards a throat between fuel and the door, and the front of the door.

Preferably the main manifold body is provided with a base with a cover plate or lid to enable easy access and manufacture wherein the base is generally channel shaped with the affixed lid forming an internal path inside for air wherein the lid in use is adapted to be attachable underneath a base of a firebox. Preferably the manifold assembly includes a manual over ride control device comprising a slidable cover plate joined to an operating rod which in use can be slidably moved to seal or open at least one aperture in the primary air passageway. Preferably the manifold body is provided with mounted ends whereby the main part of the manifold body is spaced or suspended from below the firebox wherein the mounted ends are located at the edges of the firebox.

In a second aspect the invention resides in a method of assembly for the manifold assembly for managing and controlling air flow for a firebox as disclosed above, the primary and secondary passageways having a base and lid or lids, the steps of the method include:

Assemble the lower body portion by first arranging the primary base portion over the secondary base portion to form a cruciform base shape

Fit the primary lid to the primary base portion

Fit the secondary lids to the secondary base portions to form the lower body portion

Fit the lower body portion to the underside of the firebox with the lids abutting the firebox

Fit the side and upper portions to the firebox

In a third aspect the invention resides in a method of assembly for the manifold assembly for managing and controlling air flow for a firebox as disclosed above, the primary and secondary passageways having a base and lid or lids, the steps of the method include:

- arrange the primary lid between and under the secondary lids;

- place the primary base portion on top of the primary lid to form the primary air

passageway and part of the secondary air passageway;

- place the secondary base portion on top of part of the primary base portion and the secondary lids to form the cruciform shape and the secondary airflow path;

- affix the lids to the bases to form the main body portion of the manifold assembly;

- affix the main body portion to the underneath of a firebox;

- affix side and top portions to sides of the firebox

- place fuel in the firebox and ignite to start combustion and produce heat. Preferably the air control means can be inserted in the entry means of the manifold assembly.

Preferably an override device can be inserted in the main body portion before the lids are affixed to cause a significant more air to enter the primary air ducting.

Brief Description

The invention will now be described, by way of example only, by reference to the accompanying drawings, some of which are partial views:

Figure 1 is a perspective view in accordance with a first preferred embodiment of the invention but also in a cut out view showing inside the firebox and assembly.

Figure 2 is a perspective view of the base parts of the manifold assembly

Figure 3 is a perspective view of the covers or lids for the base of the manifold assembly

Figure 4 is an in use rear plan view of the manifold assembly. Figure 5 is an in use rear plan view of the bases without the lids.

Figure 6 is an in use top plan view of the bases connected together without lids. Primary is sitting on top of the secondary with the primary being directly abut the base of the box followed by the secondary base.

Figure 7 is a similar perspective view to that of figure 1 to the manifold assembly fitted to a firebox but in a second embodiment with the secondary being split in the upper part of the firebox and upper pathway. Figure 8 is a similar view to that of figure 7 but without a front being split in the front and sides of the manifold.

Figure 8A is a cross sectional front view of a top portion of the front of the firebox. Figure 8B is a side view of the front of the firebox as per figure 8A.

Figure 9 is a similar view to that of figure 2 but related to figure 8, showing in a perspective view the primary and secondary, bases and lids.

Figure 10 is a similar view to that of figure 3.

Figure 11 is perspective view of the assembled manifold without the firebox but in a cut out form showing inside the assembly.

Figure 12 is a top plan view of the assembled manifold similar to figure 6 without the lid but showing variations in the manual override function and the primary separator. Figure 13 is a top plan view of the assembled manifold similar to figure 7 with the lid but showing variations in the manual override function and the primary separator.

Description of Drawings

The following description will describe the invention in relation to preferred embodiments of the invention, namely a firebox manifold assembly and to a method of operation. The invention is in no way limited to these preferred embodiments as they are purely to exemplify the invention only and that possible variations and modifications would be readily apparent without departing from the scope of the invention. To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and application of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be limiting. As shown in a first embodiment of the invention figures 1-6 there is a manifold assembly 1 for a firebox 2. Each firebox 2 has in use, a front 3, a rear 4, top 5, bottom or base 6, and upright sides 7 as shown in figure 1 which forms an internal therein adapted for burning fuel. A door (not shown) can be located at the front 3 of the firebox 2. Figures 7-11 show a second embodiment of the invention where the secondary air is split in a different location to the first embodiment ie in an upper portion of the firebox rather than the bottom. Figures 12 and 13 show other variations such as an enlarged primary aperture and extra apertures in the primary air path which can be manually, overidden.

The manifold assembly 1 includes an assembled ducting made up of a body of several components including a lower body portion 15, upright side body portions (sometimes called risers) 16 and upper or top body portions 17, comprising a manifold- body formed with elongate hollow shapes removably joined together when in use, with a firebox 2 adapted to form an air flow path from an inlet means to an outlet means 8. The lower body portion 15 when in use is located underneath firebox 2 but with the body portions 16 & 17 of the manifold assembly 1 being located up against or next to, the sides and top of the firebox 2 oriented as upwardly angled arms but with all lower body portions, side portions and top body portions being fluidly connected together. The lower body portion 15 comprises an overall cruciform or cross body shape (when locking in a plan view as seen in figures 4-6)

Throughout the specification terms like "portion" when used in describing parts of the pathway or ducting can also be thought of or described as "members" as well. Also words such as "primary" and "secondary" are meant to denote only that the air or air flow is travelling or being directed to a certain position within the firebox 2 with respect to the fuel or to what is being burnt or combusted. Therefore the word "primary" is being used for describing the air flow being supplied and directed to assist in the combustion generally at a lower portion of the firebox, while "secondary" denotes the air or air flow generally going to an upper part of the firebox 2. Arrows have been added to the figures to show the main direction of the air flow during the use of the manifold assembly in firebox 2. At a rear portion of the firebox the secondary inlet means 21 feeds air laterally to mainly go up the side walls to fluidly join the horizontal ducting 17 with some air being directed to the front and then up the upright tubing 16f to above the inside of the door and in general to be above the fuel.

In general through out the specification the ducting except for the tubing can be located outside the firebox requiring minimally an outlet into the inside of the firebox 2. This however can be varied depending on how heat resistant the ducting and tubing is made. Only the horizontal side ducting and front top ducting are fluidly connected together as a secondary air feed for feeding air to an upper portion of the inside of the firebox 2 while the rear horizontal top ducting is connected via a primary air feed for mainly a lower portion of the inside of the firebox. The primary inlet means 20 feeds air to inside the firebox, to go behind the fuel adjacent to a back wall in an upright ducting 16b firstly to outlet tube 61 (at lower end of the wall) and then up the wall only at the beginning of combustion, to outlet tubes 65 at the top while a front feed from the primary inlet means 20, feeds to a lower portion at or adjacent the fuel.

The air feed to above the door by the secondary inlet means 21 including outlet apertures to push any particulates at the top, downwards towards the fuel throat and a downward feed to push air down and across the inside or outside of the door to enable viewing there through. This is shown in figures 1 and 7. In another method of supplying air to the front inside top of the door is shown in figures 8, 8A and 8B.

In general a fire box has a standard air circulation path which starts from the bottom of the firebox to then move upwards generally to the front and then upwards past a baffle plate to travel back to the outlet 8.

The manifold body of the manifold assembly 1 includes two separate ducting air pathways forming a first pathway or primary ducting 18 and a second pathway or secondary ducting 19 as labelled in figure 1. The primary ducting 18 functions and is designed to provide in- coming air to the fuel to assist in combustion generally at a lower portion of the firebox 2 whereas the secondary ducting.19 is adapted to provide air for encouraging better burning of particulates produced from the combustion with the air finally exiting the inside of the firebox 2 through the outlet means 8 located at the top of the firebox 2.

The lower manifold body 15 includes entry means for air in the form of first or primary entry means 20 and second or secondary entry means 21 which each comprise downwardly oriented tubular members having open to atmosphere entry ends and exit ends. As shown in figure 1 these entry means 20 & 21 can also have a ring or sleeve member slidably attached around the outside of the tubular members which can assist with air entry via other tubing fittings etc. The entry means 20 & 21 are oriented at right angles though other angles are possible, to the rest of the lower body portion 15 and lead to the rest of the lower body portion 15 from entry apertures 25 (primary aperture) and 26 (secondary aperture) (see fig 2) which can be called primary and secondary entry intake apertures 25 and 26. The rest of the lower body portion 15 comprises a flat like hollow elongate box like member including a central primary air pathway 27 between two parallel side secondary paths 28 & 29 whereby the air in the central primary pathway is moving in the opposite direction to the air in the secondary paths 28 & 29 as shown by the directional arrows in the figures.

For the lower manifold body 15 there is a base and removable cover or lid. When in use the manifold lid is affixed to the manifold base with the manifold lid 39 being removably affixed to the outside under surface of the firebox base 6 with the base of main manifold body 15 being downwardly exposed with the entry means 20 and 21 pointing substantially downwards as shown in figure 1. Figure 1 is a partially exposed perspective view showing the manifold assembly 1 through cut out portions of the firebox 2.

As shown in figures 2 and 3 the manifold body 15 includes a primary base portion 35, secondary base portion 36, secondary covers or lids 37 and 38 and primary cover or lid 39. Primary lid 39 fits down on primary base portion 35 as shown by the dotted arrows in figure 2. The underside (in use) of primary lid 39 is shown in figure 3. Secondary lids 37 and 38 fit down on to the end portions of second base portion 36 to form secondary feeds in opposite direction left to right on each side of the firebox. The primary base portion 35 has a length appropriate to the distance between the two inlets 20 and 21 and the size or dimensions of the firebox 2. As shown in the figures the lids or covers can be for example cover plates.

Primary base portion 35 comprises an elongate planar member having a length, sides 35a and ends 35b & 35c with up-stand base walls 40 forming a part of the air pathways 27, 28 and 29 as mentioned above. The shape of primary base portion 35 with the base walls 40 can be thought of as being channel-like with different configurations also being possible while still providing controlled splitting of the incoming air.

The primary lid 39 also has a length, sides 39b and ends 39c (out feed) & 39d (out feed), relating to the air flow as shown in figure 3. Primary base portion 35 has sides 35a, ends 35b (in feed) &.35c (out feed). Secondary base portion 36 has sides 36a, ends 36b (out feed) and 36c (out feed) while secondary lid 37 have sides 37a and ends 37b (out feed) & 37c (out feed) and similarly for the other secondary lid 38 with sides 38a and ends 38b (out feed) & . 38c (out feed). Primary base portion also has a fold line 35

Also shown as being included with primary base portion 35, is a manual override air control device comprising at least one plate member 43 provided at one end of an operating elongate member 44 (for example this can be a rod shaped member 44) whereby the plate member 43 in use is adapted to cover at least one aperture 45 in the primary base portion 35 to over-ride the incoming air which is controlled. In figure 2, aperture 45 is shown for example as being in the shape of a triangle though other shapes and positions are equally possible. Rod member 44 is located parallel to the length of the base portion 35. The override device is designed to allow significantly increase the incoming air feeding the primary base portion 35, to cause there to be more air being directed to the fuel if required. In a variation for the manual override there can be a second plate member 43a joined by a rod like member 44a to cover aperture(s) in the flared portion of the base 35.

The primary lid 39 which inter-fits with primary base portion 35 is a planar member, elongate with ends whereby the ends have landing means 47 and 48 to in use be abutted and fixed to the base 6 of the firebox. This abutting uses an outer surface as shown in figure 2. Each base 35 and 36 have up stands 49 to receive fixing means via apertures 49a in the lids 37-39. The fixing means can be bolts or screws though other forms of fixing are possible that can be either removable and/or non removable such as riveting or welding. Aperture 45 is located as shown in figure 4 & 5 between entry apertures 25 and 26 being almost in the same plane and in this example being triangular is shape.

Primary lid 39 has on its underside (fig 3) a series of up-stand walls or rails 39a but of less height than base walls 40 of the primary base portion 35 but function as sealing and or abutment rails against base walls 40 to keep the air within each appropriate pathway and to provide support there between if required. The orientation of the lid walls 39a follow the base walls 40 of the primary base portion 35 as required for sealing and/or abutment. The height and shape of the walls can be varied to suit particular requirements for sealing abutment and manufacturing. Other forms of sealing can also be included such as gaskets or flexible sealers. The primary lid 39 also includes at least apertures 50 and 51 to allow incoming air or air flow to be directed and pass there through and out as required by the orientation and positioning of the air splitting. Aperture 50 can be located as a central aperture connected to the primary path 27 to the lower front portion of the firebox to pass or be directed to the fuel being combusted. The other aperture(s) 51 can be located as outlets from the secondary paths 28 and 29 on least one side of the aperture 50. More or less pathways can be used if required. These apertures and any of the other openings or ends can be shaped as required but in this example they are rectangular with bevelled edges to assist the air flow as shown in figures 2 and 3. Air flow exiting openings of the primary and secondary ducting 18 and 19 also have particular shape with bevelled edges as necessary. This is shown in figures 2 and 3 where the ends 35c & 39d of primary base portion 35 and the lid 39 have at least one bevelled edge and also the ends 36b, 36c & 37b, 38b of the secondary base portion and lid have a bevelled edge or recess. Ends 37c and 38c of the secondary lids include a slidable sealing end face when each such end of each lid interfits with the sides 39b of the lid 39.

Secondary base portion 36 as seen in figure 2 includes an elongate channel shape that allows it to abut and cross with primary base portion 35 to form a cross or cruciform shape whereby the secondary base portion 36 is oriented transverse to primary base portion 35. Secondary base portion 36 is for the secondary air to distribute incoming air firstly to the sides then the top and then the front of the door inside of the firebox. Secondary base portion 36 overlaps the primary base portion 35 with its middle by rising and is formed as an elongate member with up stand walls forming a channel-like member. In cross section, overall, secondary base portion 36 has planar ends (ie ends that are at right angles to the sides but other shapes are possible) and a raised middle portion (if orienting the base portion upside down). Secondary base portion 36 also has the aperture 36 located in the centre of its length in the raised middle portion. The secondary portion 36 could be thought of as crossing or bridging over or overlapping a portion of the primary base portion 35, as shown in figures 4-6.

As shown in figures 2, 4 & 5 air separating means 54 and 55 are in the form of plate-like members which are located and oriented close to or at the exit ends of the entry means 20 and 21, within apertures primary aperture 25 and secondary aperture 26 whereby the incoming air can be divided or split accordingly. Air separator means 54 separates the air into front and back of the lower portion of the firebox while air separator means 55 splits the secondary air left to right or to the sides and then to the top of the inside of the firebox 2. In general the primary ducting 18 directs air to a lower portion inside of the firebox and the secondary ducting 19 does so for an upper portion. For the primary ducting 18 the split forms a major portion of the air to go to the back 4 of the firebox 2 at a lower portion of the firebox 2 and a smaller portion of the air can be directed to the front 3 of the firebox 2, at the lower end. For the secondary ducting 19 the air can be split with one portion of the split going to the top of the firebox at the rear and sides and the rest of the split going to the top of the door.

As shown in figure 2 primary base portion 35 has a flared portion 35e at one end 35c opposite to the end 35b where the air enters path 27 i.e. at the end where the secondary base and lid are located. The flared portion 35e allows the primary air flow 27 to extend beyond the length or extent of the two side secondary air flows 27 and 29 which means that they are recessed at 35f to allow the secondary air flows to be directed into the secondary base portion or side arms to go both left and right to the sides of the firebox 2. The flared portion 35e is a back primary feed to a rear primary upright square tubing arrangement 16b which then leads to a smaller tube 61 as seen in figure 1.

Primary separator 54 is angled parallel with the orientation of the secondary ducting with respect to the primary ducting ie from left to right if a user stands in front of the front of the firebox 2. Separator 55 can be angled to be in line with the length of the primary ducting as seen in figures 2, 4, 5 & 6. Located on the opposite side of the primary base portion 35 to that used by the primary air is another separator means (not shown) which (in use downwardly) protrudes there-from to meet and abut the separation means 55 from the secondary base portion 36 when the secondary base portion 36 is fitted to the primary base portion 35 the two separators meeting to form a single splitting air barrier for the ducting formed when assembled to form the left and right arms of the secondary air flow as on each side of the firebox. In another variation separation means 55 can be formed as a single piece.

Secondary lids 37 and 38 as shown in figures 2 and 3 each fit and fix to the ends of secondary base portion 36. The position of this fixing can located anywhere to suit ease of use and assist in sealing the air paths. These secondary lids 37 & 38 have slidable sealing means or lapping means 57 at one end, so that when fitted with primary and secondary base portions 35 and 36 with primary lid 39, there is an overlap over the corresponding joint to" seal accordingly. Each of the joints between lids and bases can also have seal rebates to make the seal, an air seal of serpentine extent.

Figure 4 is a rear view of the bases and lids connected together underneath a firebox 2. Figure 5 is another in use rear view but this time of the base without the lids whereas figure 6 is a top plan view of the bases 35 & 36 without the lids. Figures 5 and 6 show the bases of the primary and secondary assembled together in an overlapped criss-cross or cruciform shape as seen in plan view whereby the primary base 35 sits on or laps with the secondary base 36 as shown by the orientations of figure 2. Just the end portion (called the flared portion 35e) of the primary base portion 35 sits on top of a middle portion of the secondary base as seen in figure but when being installed this is flipped around to be attached to the underside surface of the firebox 2. So figure 5 is a rear view of the connected bases and figure 6 is top view of the same connected bases of figure 5. The flared portion 35e acts like a ramp which can be sloped approximately from the line 35g whereby the slope can be any degree of slope required such as from level to rising or falling to eventually leave the flared portion via a downwardly slope edge 35c as seen in figure 2.

Installation wise the primary base 35 is attached and/or simply end lapped with the secondary base 36 followed by the lids 37 & 38 with primary lid 39 first to cover the primary base 35 followed by the secondary lids 37 & 38. After the lids, 37-39 the manifold assembly can be removably fixed to the base of the firebox 2. This sequence of assembly can be varied to suit any sealing requirements between the primary and secondary pathways and between the lids and bases.

Bleed hole(s) 60 are also included as shown in figure 5, in the primary base portion 35 and also anywhere, where required. Also in figure 5 is that apertures 25 and 26 are also formed having a raised peripheral circular walls 58 (downwardly when in use) protruding further from the primary and secondary base portions 35 and 36 combined with the wall 58 being set back from each aperture 25 and 26 (forming an inner ledge 59), to make it easier fit the entre manifold assembly if required.

As shown in figure 1 once the air flow enters the lower manifold body 15 underneath the firebox 2, primary air flow coming in from (at the front of the firebox 2) inlet means 20, is split by air separator 54 to go back and forward from inlet 50 (see fig 2), through the central primary flow path 27 air through ducting 16b up the outside of the end rear wall 4 to a rear primary outlet 61 poking through the back wall 4 of firebox 2 and the air going to the front is also from outlet 55 and travels up through to be in also a lower portion of the inside of the firebox. As mentioned previously upright ducting 16b is shown as extending to the top of the firebox even though it is a primary air intake which is generally adapted to be directed to a lower portion of the inside of the firebox in at least one instance in the process of combustion ie initially during the start of combustion, primary air is directed to the top in a horizontal tubing 17 to be expelled there from, to assist and then when pressure is built up inside from the outlet 8 to inside, then this air is automatically turned off and only comes out of tubing 61. This horizontal tubing 17 located at the top and back of the firebox is not fluidly connected to the other horizontal tubing which is for the secondary air.

For the secondary air, air flow comes in from inlet means 21 to be split by air separating means in at least two ways and positions. One split is through to the front, to paths 29 (opposite air direction to that of the primary air) and out through apertures 51 (see figs 2 and 3) to the front and top (or above the fuel or an upper portion of the inside of the firebox) of the firebox, and from the other split, the incoming air is further split by the separator 55 to go sideways or left and right as secondary side feeds 28, then through side ducts 64 and out through air tubes 65 at the top of the firebox 1 which such tubes 65 can have outlet apertures 66 of say for example 2-3mm diameter. Tubes 65 can be circular of smaller dimension that the in feed box sections 17 as seen in figure 1. The number and orientation of apertures or numbers of tubes can also be varied. For the secondary ducting the door (not shown) can be washed by air as shown in figure 1 which can include shaped tubing 67 with apertures 68 located at the top of the door but behind the door glass. Tubes 65 as seen in figure 1 extend across the complete width of the firebox ie from side to side to form a continuous tube.

Arrows are located on most of the parts or components to indicate a general air flow direction. Also as well as the mounting and apertures there can be tolerances between parts to allow movement through temperature fluctuations during firebox use and also to allow for manufacturing differences which then provides a sliding interface between all parts if required. Separator means 25 also serves to mount the override device 43 as shown in figures 2 and 5. The manifold assembly 1 will function by itself, by being attached to any suitable firebox but can be made more efficient if combined with some sort of air control means (not shown). The air control means can be fitted to the entry means 20 and 21 so that there is a primary air control means and secondary air control means. For example each air control means can comprise a movable planar member which is shaped and dimensioned to move vertically (when in use) within the entry tubular portion of the entry means to either block or restrict any incoming air according to the air required for combustion anywhere in the firebox 2.

The movable planar member of the air control means is in the form of a disc wherein each disc comprises a different weight to the other. In this case the weight of the secondary disc will be the heaviest whereby at rest or when the first has not started both discs can located at the bottom on the stop but the secondary disc at this position because of the shape of the walls of the air control means will block any flow and for the primary disc this position will enable a full entry of air flow. The first and second planar members are slidably mounted on a central pole with the cavity of the entry portion and can only move from a lower position to a higher position as governed by stop means. There also can be a method of assembly for the manifold assembly for managing and controlling air flow for a firebox as disclosed above, the primary and secondary passageways having a base and lid or lids, the steps of the assembly could include:

- arranging the primary lid between the secondary lids on a flat support surface;

- placing the primary base portion on top of the primary lid to form the primary air path and part of the secondary air path;

- placing the secondary base portion on top of part of the primary base portion and the secondary lids to form the cruciform shape and the main secondary airflow path;

- affixing the lids to the bases to form the main body portion of the manifold assembly;

- affixing main body portion to the underneath of a firebox;

- affixing the side and top portions to the sides of the firebox

- placing fuel in the firebox and ignite to cause combustion and heat as required.

Another method of assembly is to:

Assemble the lower body portion by first arranging the primary base portion over the secondary base portion to form a cruciform base shape

Fit the primary lid to the primary base portion

Fit the secondary lids to the secondary base portions to form the lower body portion Fit the lower body portion to the underside of the firebox with the lids abutting the firebox

Fit the side and upper portions to the firebox

Alternatively the side portions can be installed before any of the other steps or the lids could be fitted to the underside of the firebox before fitting the bases.

This method can be altered such as by inserting air control means in the entry means of the manifold assembly after the assembly has been fitted and before ignition. Also an override device can be inserted in the main body portion before the lids are affixed. Method of operation for the manifold assembly including an air control disc, for one cycle for burning or combusting a fuel.

At cold or re-stoke the primary air control disc is at rest at its bottom stop at full air in-flow position. Air will be incoming and be split by the primary separator with most going to the back and the rest going to the front of the fuel.

The secondary air control disc is at rest on its bottom stop at its minimum air in-flow position ie almost complete blocking any incoming air flow.

As the fire accelerates, air is drawn through each air control disc and they are immediately doing different tasks as a twofold effect.

-As the fire accelerates the primary is flowing at maximum air inflow whilst the secondary is restricting air inflow with a heavy disc held in its seat by the bottom stop, slowly rising as the demand for air increases.

The twofold effect is that the secondary ie the upper part of the firebox is heated faster than usual than existing fireboxes and the burn rate of the lower area of the firebox is kept in check - does not go too fast or too slow.

As the fire continues to accelerate, the light primary disc is drawn up through the seat to its top stop. This means that the light primary disc is now reducing the air flow which also controls the burn rate. The heavy secondary disc is also being raised but the air flow is being increased. The fire now enters its slow burn rate until it further slows at the charcoal stage (at the end of burning of the fuel). This means that there is less demand for air.

The heavy secondary disc now settles back to its bottom stop stopping cold air chilling the fire box which conserves heat for Delta T.

The light primary disc is still at its top stop, only slowly descending against the air control disc tapers, until it drops through its seat to its bottom stop. As this is the maximum incoming air flow position, air fans and so heats, the remaining fuel. This drives Delta T back up into the safe temperature zone above 125 Fahrenheit.

The cycle is now over and the fire is automatically reset..

Figures 7-10 Second embodiment - extra air split at the top

As shown in figures 7-10 the air paths can be varied to allow for the secondary splitting to occur in the side portions and top portions rather than just in the primary portion as shown in figure 1. These figures use the same number references where possible. This embodiment saves on the need to have secondary front wall ducting.

As shown in figure 7. the incoming air at inlet 21 leaves the secondary ducting 19 to the left and right ie to the side portions 16 and on to the top portions 17 (at the sides) and out of air tubes 65. However the top portion 17 and/or poritonl6 can be split to form at least two secondary paths 70 and 71. These paths are shown with a configuration of path 70 being an upper smaller section in volume than a lower section 71. Upper path 70 can be directed to the throat wash and door wash while the lower path 71 can be used to direct secondary air to the air tubes located at the top of the insider of the firebox 2. This configuration can be varied by for example by being side to side or more than two paths. The split can be formed by having a separator 72 located in any configuration inside the horizontal (sides) tubing 17 as shown in figure 7. Figures 8, 8 A and 8B show another way of providing secondary air to the inside top front of the door and a throat position in front of the fuel. As mentioned before air can be provided at the back of the firebox through upright side tubing 16 to the secondary horizontal side tubing 17 at the top through bleed holes or by splitting the horizontal tubing 17 using a horizontal separator plate 72 which then fluidly leads to the top of the door 84. The secondary air can also be directed via the front up the upright side tubing at the front to the top of the door 84.

As shown inside in any firebox there is often a baffle plate below a top wall 5 whereby at the top corner of the door within the firebox, there is a front top air tunnel formed having a front wall 82 forming part of the front wall of the firebox, a back or rear wall 82A and a middle wall 81 which extend across the front of the firebox so that there is a front tubular air pathway and a rear tubular air pathway. Horizontal side tubing 16 as shown includes a bleed hole or aperture split into outlet portions 85 and 83 by at least a lower portion middle wall 81. As shown in figure 8B in cross section this tunnel is wedge like in shape whereby a lower end of front air pathway is open as a slit like opening to direct air downwardly over the inside of the door to keep it clear for viewing. The air exiting outlet portion 85 is directed into each end of the tunnel to then exit downwardly. The air exiting outlet portion 83 which are a series of holes spaced along rear wall 82A of the rear air pathway has outlets 87 in the figure 1, 7 and 8 where a front wall is cut away to reveal the back wall 82 A with the outlets 87 which are adapted to direct air inwardly towards the throat area in front of and above the fuel at the front of the inside of the firebox 2.

Figure 9 shows the primary and secondary base portions 35 & 36 and secondary cover plate or lid 37. The secondary lid 37 and secondary base portions are the same shape as in figures 1-6. Primary base portion 35 is essentially the same shape as before but without the two outer flow paths 29. Therefore the lid 39 will be a different shape as it is shaped to fit the smaller base 35. Lid 39 has an outer surface 73 which is stepped having raised ends that directly in use abut the under surface of the firebox 2. This is a similar shape in principle to that shown in figure 2 having a primary feed end 35c/39d. As seen in figure 8 incoming air enters via inlet 21 through central aperture 26 and out left and right to each side of the fire box 2.

Figure 9 like figure 3 shows underneath the lids which is the lid side that faces inside the ducting path. The main difference to the figure 3 lid 39 is that there only one air outlet aperture 50. The rest of the lids 37-39 have the same sealing rails fixing points recesses and supports as in figure 3. The outlet ends of the matched lids and bases are also recessed to fit together to form channelled exits. Also shown in figure 7 (similar to figure 1) a back ducting 17a has outlet apertures 65 at the top of the firebox 2 for part of the secondary air and at the front and top of the firebox 2, there is a front secondary ducting 17b and door wash feed 17c shown. There is no front second wall ducting to feed the front secondary ducting 17b instead front secondary ducting 17b is feed via the rear wall secondary ducting up the wall to the top and then towards the front of the firebox 2 to be directed where required. The front secondary ducting 17b and door wash feed 17c can be feed either from paths 71 or 72 as desired.

Figures 11-13 Embodiments of the primary separator and primary inlet

.

As seen in figures 11-13 the primary separator 54 can be formed of two portions whereby there are two spaced walls 54a and 54b separated by a distance 54c and inlet aperture 25 is now larger than before and now extends to the full width of the base 40. Previously inlet 25 was only the width to the primary air path 27. Therefore the diameter of the inlet 25 can be varied accordingly. This means that there is now a portion of primary air that can be directed into the secondary air path 29 as or if required.

Advantages

a) More efficient burning or combustion

b) Less pollution

c) Modest cost

d) Simple installation

e) Robust construction

f) Controllable operation

g) Splitting of air for primary and secondary

h) Controlled long burn fires or combustion are possible

Variations

Throughout the description of this specification, the word "comprise" and variations of that word such as "comprising" and "comprises", are not intended to exclude other additives, components, integers or steps. The manifold assembly seeks to effectively slow the air flow down in a firebox when compared to known fireboxes whereby there are lower air pressures which are more likely to be equalized to cause the air and combustion to be effectively managed to achieve long and cleaner burns than before.

Though tubular is mentioned for the shape of the manifold there can be variations and different combinations of this hollow shape from circular to any other cross sectional shape that is elongate and able to enclose the air such as for example square or rectangular shaped in cross section which can be straight, branched, bent or angled as required. The tubing can be formed as components or cast complete, in one shape for the whole assembly. Apertures 25, 26 and 45 are circular or triangular though other shapes are equally possible. The walls can act as both sealing the air within and as walls to the passageways. Other parts of the ducting that form the assembly can be formed in parts such as having separate side portions 16 and 17.

Two air inlets are shown but there can be more or less as is necessary. The air separator means are shown as directing or splitting more air to the back or front but this can be varied to suit. Also though below the fuel and above the fuel are mentioned as directions to direct air, air can be directed to anywhere within the firebox as required. The manifold body is shown as a cross or cruciform shape as seen in figures 4-6 but this shape can be varied whereby the secondary can be completely separated from the primary. In other options the lids and bases can be swapped around to allow either downward or upper access or even side access if required.

Manual override air control device 43 as shown in figures 2 and 5 can also be included in the second embodiment though it is not shown in figures 7-10. Additionally override air control device 43 ^" which functions to allow more air to be allowed in than is currently being controlled, can include not just at least one plate 43a to slide oyer aperture 45 but another plate 43b to also be slidably moved over aperture(s) 45a further up the primary air path and located in the flared portion 35e. Plate 43b can be connected to plate 43 via a tubular or rod like member 44a like member 44. This can be seen in figures 2, 4 and 5.

Though the primary inlet is shown as being located at the front of the firebox and the secondary inlet being at the rear, these positions can be altered to suit as it is the pathways leading from these inlets 20 and 21 where ever they are, that can be changed to match as it is the separating and splitting that is important with respect to portions of the inside of a firebox and the inlets.

The apparatus can be formed from any suitable material such as for example cast aluniinium or steel or both. Also though the passageways in the main base portion 15 comprise bases and lids, it is also possible to manufacture or make the passageways in one piece. The air control means can also comprise a flap member (not shown) hinged or pivoted at the top to allow the closing or opening as required of the incoming air. Also though lids or covers are shown for the manifold in some cases the base of the firebox may be suitable thereby not needing any lids.

It will also be understood that where a product, method or process as herein described or claimed and that is sold incomplete, as individual components, or as a "kit of Parts", that such exploitation will fall within the ambit of the invention. These and other features and characteristics of the present invention, as well as the method of operation and functions of the related elements of structures and the combination of parts and economics of manufacture, will become more apparent upon consideration of the following description with reference to the accompanying drawings, all of which form part of this specification, wherein like reference numerals designate corresponding parts in the various figures.

For purposes of the description hereinafter, the terms "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal" and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However it is to be understood that the invention may assume various alternative variations, except where expressly specified to the contrary. It is also to be understood that the specific devices illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the invention. Hence specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting. An override option can be included with the secondary entry means 21. Primary entry means 20 can be larger in diameter or size whereby instead of being a diameter being almost equal to the width of the primary air path 27, primary entry means can extend into the adjacent secondary air paths 29 either one or both air paths 27.

It will of course be realised that while the foregoing has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is hereinbefore described.