A composter

Abstract

A composter 1 comprising a basket 3 and a housing 5. The basket comprises a top, a bottom and a periphery. The basket is dimensioned to hold a basket volume of process material that is at least a minimum basket volume. The housing houses the basket and defines a housing volume sealed to exclude rodents from the process material. The bottom of the basket comprises exit-openings together having an area at least equal to a minimum exit proportion of a square of a cube root of the minimum basket volume. The exit-openings are each dimensioned to permit the passage of any notional sphere smaller than a first diameter. The exit¬ openings, and any further openings in the bottom of the basket, are each dimensioned to block passage of any notional sphere larger than a second diameter.

Description

[0001] P1912PCAU

[0002] 1

[0003] A COM POSTER

[0004] FIELD OF THE INVENTION

[0005] The invention relates to composting.

[0006] BACKGROUND TO THE INVENTION

[0007] Composting is an aerobic process by which organic materials such as kitchen scraps and garden waste are decomposed into nutrient-rich ‘compost’ that can be returned to the soil to aid in plant growth.

[0008] Decomposing organic matter can attract rodents and other vermin. Accordingly various existing composters are sealed to varying degrees whereas sealing risks anaerobic activity which is considered highly undesirable.

[0009] To address these competing concerns some gardeners regularly open their composters and turn the compost to aid in aeration. This can be laborious.

[0010] The present invention aims to provide improvements, or at least alternatives, in and for compositing.

[0011] It is not admitted that any of the information in this patent specification is common general knowledge, or that the person skilled in the art could be reasonably expected to ascertain or understand it, regard it as relevant or combine it in any way before the priority date.

[0012] SUMMARY

[0013] One aspect of the invention provides a composter comprising a basket; and a housing; P1912PCAU

[0014] 2 wherein the basket comprises a top, a bottom and a periphery; the basket is dimensioned to hold a basket volume of process material that is at least a minimum basket volume; the housing houses the basket and defines a housing volume; the housing comprises a housing floor; an inlet openable to allow process material to be added to the top of the basket; an outlet openable to allow process material that has fallen through the bottom of the basket to be removed from the housing; the housing volume is at least a minimum volume multiplier times the basket volume; the bottom of the basket is at least a minimum elevation above the housing floor; at least a minimum clearance proportion of the periphery of the basket is spaced horizontally from the housing by at least a minimum clearance dimension; the bottom of the basket comprises exit-openings together having an area at least equal to a minimum exit proportion of a square of a cube root of the minimum basket volume; the exit-openings are each dimensioned to permit the passage of any notional sphere smaller than a first diameter; P1912PCAU

[0015] 3 the exit-openings, and any further openings in the bottom of the basket, are dimensioned to block passage of any notional sphere larger than a second diameter; the minimum basket volume is 100 L; the minimum volume multiplier is 1.4; the minimum elevation is 250 mm; the minimum clearance proportion is 50%; the minimum clearance dimension is 50 mm; the minimum exit proportion is 50%; the first diameter is 75 mm; the second diameter is 300 mm.

[0016] The minimum basket volume may be 120 L but is preferably 200 L, e.g. 350 L or more preferably 400 L. Optionally, the minimum volume multiplier is 3 or more preferably 4. The minimum elevation may be 350 mm or more preferably 400 mm.

[0017] Preferably the minimum clearance proportion is 85% and / or the minimum clearance dimension is 75 mm.

[0018] The minimum exit proportion may be 70%. Alternatively it may be 80% or more preferably 90%.

[0019] The first diameter may be 100 mm or 125 mm. The second diameter may be 250 mm or 200 mm.

[0020] The housing floor may slope towards the outlet. P1912PCAU

[0021] 4

[0022] Preferably an area of the housing floor as viewed in plan is at least 1 .5 times, e.g.

[0023] 2 times, or more preferably 2.5 times an area of the bottom of the basket as viewed in plan.

[0024] According to certain embodiments the basket is dimensioned such that a smallest notional upright cuboid in which the basket fits has a smallest edge dimension and a largest edge dimension not more than 150% (e.g. not more than 140% or more preferably not more than 130%) of a smallest of the edge dimensions; and a cuboid volume not more than 150% (e.g. not more than 140% or more preferably not more than 130%) the basket volume.

[0025] Preferably the largest edge dimension is not more than 125% of a smallest of the edge dimensions. Optionally, the basket volume is not more than 2,000 L, e.g. not more than 1 ,300 L, or more preferably not more than 800 L.

[0026] Another aspect of the invention provides a method of composting comprising lining the bottom of the basket of the composter with compostable material to occlude the exit-openings; then supplying process material to the basket; then allowing the compostable material to compost to cause process material to fall through the exit-openings; then removing from the housing, and via the outlet, the process material that has fallen through the exit-openings.

[0027] Preferably the compostable material comprises cardboard. The supplying process material may comprise a household directly supplying the household’s kitchen scraps e.g. in contrast to commercial waster collector collecting household scraps P1912PCAU

[0028] 5 from multiple households and supply those scraps to a commercial scale composter.

[0029] BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a front view of a composter with its inlet and outlets closed;

[0031] Figure 2 is a cross-section view corresponding to the line ll-ll in Figure 1 and showing the inlet and the outlet open; and

[0032] Figure 3 is a plan view of a bottom of the basket corresponding to arrow A in Figure 2.

[0033] DESCRIPTION OF EMBODIMENTS

[0034] The following examples are intended to illustrate to enable reproduction and comparison. They are not intended to limit the scope of the disclosure in any way.

[0035] The composter 1 comprises a basket 3 and a housing 5. The housing 5 comprises an inlet 7 and an outlet 9 each of which is normally closed. The basket is preferably suspended with the housing.

[0036] The inlet 7 comprises a closure in the form of a lid. Other forms are possible. The closure is preferably pivotally mounted. The closure of the inlet 7 is configured to retain its open position to leave an operator with both hands free to supply the process material. In this example, the lid is pivotally mounted and supported by a pair of gas struts. Whilst one or more gas struts is a preferred mechanism for holding the open position, there are other options.

[0037] The outlet 9 takes the form of a door mounted to swing outwardly to permit access to the bottom of the interior of the housing.

[0038] This example of the housing 5 is square in plan and has a bottom cuboid section with a square 1.2 m x 1 .2 m footprint and about 400 mm high. This bottom cuboid P1912PCAU

[0039] 6 section is capped by a set of mutually similar walls that taper inwardly to form a truncated four-sided pyramid section atop the cuboid section. The top of this truncated pyramid section is in plan a 1 m x 1 m square and is fully spanned by the lid 7.

[0040] The basket 3 is upright and cylindrical and 00.85 m by 0.85 m. The wall of the basket is air permeable. In this example it is formed of four panels of 25 mm x 25 mm x 03 mm mesh panels mutually connected by four narrow upright connecting strips. The panels are welded to the panels in this case. Preferably the basket wall has (or walls together have in the case of a polygonal basket) an open area of 70% or more. The mesh and frame arrangement of the described example has a wall comprising an open area of about 85%.

[0041] The circular bottom of the basket A is open but for a trio mutually parallel 025 mm rods 11. To initialise the composter 1 the bottom of the basket 3 is internally lined with a compostable barrier material to occlude exit openings 11a between the bars 11. Cardboard such as corrugated cardboard is a convenient choice of barrier material but other options are possible. By way of example, light twigs might be placed transverse to the bars 11 and / or pads of compressed hay removed from a square bale could be employed.

[0042] Once the compostable barrier is in place process materials such as kitchen waste and garden trimmings are supplied to the basket via the inlet 7. After each supply of fresh process material, the inlet 7 is closed (and the outlet 9 is left closed).

[0043] The housing 5 comprises breather vents to supply fresh air to the process material but is preferably configured to exclude at least rodents. One such configuration comprises breather vents positioned beyond the reach of rodents such as 300 mm up a sheer exterior of the housing that rodents cannot scale. Preferably the housing is sealed to exclude rodents, e.g. the breather vents may be a set of 05 mm holes too small for a rodent to fit through. Whilst the housing preferably comprises breather vents, the housing is preferably sufficiently sealed to impede air flow so that the sealed internal environment creates a warm pocket of air that P1912PCAU

[0044] 7 helps to speed the composting process. The surrounding air trapped with the housing and surrounding the basket acts as an insulator trapping the heating generated within the basket as the process material decomposes. This may be particularly advantageous in colder climates.

[0045] The composter 1 is well adapted to domestic use to serve a single nuclear family such that new process material is supplied at least once or twice a week. The present inventor has found that opening and closing the lid 7 (in combination with the limited breather vents) provides sufficient oxygen for efficient composting.

[0046] The basket 3 has a volume of about 480 L. Basket volumes as small as 200 L may be useful in the context of smaller households whilst a basket volume of 2,000 L is considered a practical maximum for ordinary domestic use.

[0047] The basket is preferably dimensioned so that each portion of process material is not more than 600 mm, or more preferably not more than 500 mm, from free air. In the context of the 00.85 m x 0.85 m basket 3, the innermost material is 425 mm from the periphery of the basket. In the context of larger sizes it may be desirable to change the aspect ratios of the basket and / or to provide internal air supply channels. By way of example, in the context of a 01 .2 m x 1.2 m basket a cylindrical mesh inner wall might define a central air passage, e.g. a 0100 mm air central passage might run coaxially within the basket.

[0048] Whilst different basket shapes and internal air flow paths are possible, to suit the domestic market a basket having relatively square proportions is preferred particularly at basket volumes in the range of 200 L to 1 ,000 L. This allows a significant amount of material to be processed rapidly without taking up too much space in the garden.

[0049] The housing preferably has an internal volume at least 1.4 times the basket volume so as to hold twice as much air as process material. A multiplier in the range of at most five is preferred to avoid taking up too much space in the garden. P1912PCAU

[0050] 8

[0051] To supply air to the exterior of the basket, the periphery of the basket is offset from the interior of the housing by a clearance space 13. Preferably, the clearance space is at least 50 mm, or more preferably at least 75 mm. Preferably, the clearance runs all the way around the basket (corresponding to a clearance proportion of 100%), although impingements in this area are possible. By way of example a cylindrical basket might be a tight fit within a square-profiled housing with an internal transverse dimension matching the external diameter of the basket.

[0052] The bottom of the basket is an elevation E above the floor 15 of the housing 5. The inclusion of a floor guards against rodents and other vermin tunnelling into the housing. The floor 15 is inclined towards the outlet 9. In the context of a sloped and / or contoured floor and / or a sloped and / or contoured basket bottom, the elevation is measured from the average height of the floor to the average height of the basket. The elevation E is preferably at least 250 mm, or more preferably at least 400 mm. This elevation, in combination with the sparse floor of the basket, provides a high degree of contact area for supplying air to the process material and promotes advantageous movement of the process material.

[0053] The bars 11 at the bottom of the basket 3 are 25 mm in diameter and equispaced across the 850 mm diameter of the basket to define four exit openings 11a each about 156 mm wide. The present inventor has found that the configuration of the bars has a significant impact upon the performance of the composter. When composting typical household process materials, the process material does not simply fall down as a uniform mass once the cardboard rots away. Rather, the material tends to sit atop the bars leaving only the finer, more composted, material to fall down. Gaps in the vicinity of 125 mm to 200 mm are well adapted to processing typical household process materials, although gaps as small as 75 mm wide might be usefully employed, for example, in the context of a household that is processing predominantly kitchen scraps and cardboard. On the other hand, in the context of a household processing garden waste comprising small twigs, wider gaps up to 300 mm wide may work well. Some variants of the composter may P1912PCAU

[0054] 9 have reconfigurable basket floors to enable the relevant spacing to be adjusted to suit different process materials and / or user preferences. By way of example, in a rudimentary variant, the rods might simply be passed through the mess of the basket walls so that they can be withdrawn and relocated as required from time to time.

[0055] Mutually parallel bars may be convenient, although in other examples of the concept the basket floor may have a different configuration, e.g. the bars might be arranged in a zigzag formation, or indeed the floor may have an entirely different configuration. By way of example, the floor might be formed of a grid of material. A plate in which the exit openings are cut is another possibility. The exit openings might be circular or any other convenient shape. It is also possible that other smaller openings are interposed between the exit openings, e.g. the floor might comprise 150 mm diameter exit openings cut into a 25 mm x 25 mm mesh panel.

[0056] Given the multitude of shapes that the exit openings might take, it is convenient to characterise the requisite sizes of the exit openings 11a in terms of notional spheres which can and cannot pass therethrough. By way of example, the long spaces 11a are about 156 mm wide and as such would permit a 0150 mm notional sphere to pass through but would block the passage of a notional 0160 mm sphere. Preferably, the exit openings constitute most of the ‘floor area’ of the basket. Generally speaking, for larger basket volumes, there should be a larger area of exit openings. Noting that baskets can come in different shapes and sizes, it is convenient to characterise the requisite exit opening area in terms of a minimum exit proportion of a floor of a notional cubic basket. Preferably, the minimum exit proportion is 50%, or more preferably at least 80%. Noting that the bottom of the basket may have openings further to the exit openings, it is preferred that the bottom of the basket has an open area of at least 85%, or more preferably at least 90%.

[0057] The compost that falls to floor of the housing is separated from the heat of the decomposing material above. According to preferred embodiments, this relatively P1912PCAU

[0058] 10 cooler compost is attractive to worms and composting worms may be introduced to advantageously further process the material. Thus a nuclear family may supply the kitchen scraps and garden trimmings to the composter and in turn have ready access to a high-grade mixture of compost and worm castings to enrich their garden.

[0059] The composter may be formed of any convenient material (e.g. rigid plastic) but metal, e.g. steel or aluminium, construction is preferred. The metal is preferably corrosion resistant, e.g. the steel may be galvanized or otherwise treated with zinc. In a preferred implementation the housing comprises sheet (e.g. steel sheet) panels supported by a frame (e.g. steel frame). Likewise the basket may comprise mesh (e.g. steel mesh) supported by a frame (e.g. steel frame). Perforated aluminium is another option. The illustrated basket 3 comprises steel mesh carried by steel frame comprising top and bottom hoops mutually connected by the upright connecting strips.

[0060] A smaller version of the composter having basket volume of about 140 L and a minimum volume multiplier of 3.0 is contemplated. The basket is preferably at least 600 mm in height. The compost heats at the top of the basket. The exothermic reaction continues as the bacteria breaks down the organic matter.

[0061] The temperature can reach 65°C and falls to 40°C towards the middle of the basket. The top about 300 mm serves as a heat zone where a temperature of about 60°C does most of the composting. Downwards from the heat zone, the composting process continues slowly as the material cools.

[0062] To enhance the heating process, the lid is preferably black to attract heat to the top of the basket. The lid may have underside insulation to reduce heat loss at night and in cool climates and / or an insulated blanket could be used to reduce heat loss. The housing should be of a dark colour. This will help to support the warm, moist conditions around the compost basket. Black would be preferable, but dark green more acceptable for gardens. P1912PCAU

[0063] 11

[0064] The lid could be either a dome or pyramid.

[0065] The basket is preferably of corrosive-resistant material such as stainless steel mesh, punched galvanized steel, punctured aluminium sheet or plastic mesh. For a sheet basket, the openings should be at least 50%. The best composting conditions are a) a water content of between 40% and 65% and b) a minimum of 5% oxygen.

[0066] Preferred embodiments of the invention allow the feed material to be processed in optimum conditions. In a preferred variant, a suspended basket, surrounded by free air space, within a closed structure with a small number of 6 mm holes allows ventilation but protects from rodents and snakes, and the moist feed heats during composting, accelerating the process in a warm humid environment. This results in a faster composting process.

[0067] The term "comprises" and its grammatical variants has a meaning that is determined by the context in which it appears. Accordingly, the term should not be interpreted exhaustively unless the context dictates so. Likewise, the article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements unless the context dictates so.

Claims

P1912PCAU12CLAIMS1 . A composter comprising a basket; and a housing; wherein the basket comprises a top, a bottom and a periphery; the basket is dimensioned to hold a basket volume of process material that is at least a minimum basket volume; the housing houses the basket and defines a housing volume; the housing comprises a housing floor; an inlet openable to allow process material to be added to the top of the basket; an outlet openable to allow process material that has fallen through the bottom of the basket to be removed from the housing; the housing volume is at least a minimum volume multiplier times the basket volume; the bottom of the basket is at least a minimum elevation above the housing floor; at least a minimum clearance proportion of the periphery of the basket is spaced horizontally from the housing by at least a minimum clearance dimension;P1912PCAU13 the bottom of the basket comprises exit-openings together having an area at least equal to a minimum exit proportion of a square of a cube root of the minimum basket volume; the exit-openings are each dimensioned to permit the passage of any notional sphere smaller than a first diameter; the exit-openings, and any further openings in the bottom of the basket, are each dimensioned to block passage of any notional sphere larger than a second diameter; the minimum basket volume is 100 L; the minimum volume multiplier is 1.4; the minimum elevation is 250 mm; the minimum clearance proportion is 50%; the minimum clearance dimension is 50 mm; the minimum exit proportion is 50%; the first diameter is 75 mm; the second diameter is 300 mm.

2. The composter of claim 1 wherein the minimum basket volume is 120 L.

3. The composter of claim 1 or 2 wherein the minimum volume multiplier is 3.

4. The composter of claim 1 , 2 or 3 wherein the minimum elevation is at least 350 mm;P1912PCAU145. The composter of any one of claims 1 to 4 wherein the minimum clearance proportion is 85%.

6. The composter of any one of claims 1 to 5 the minimum clearance dimension is 75 mm;7. The composter of any one of claims 1 to 6 the minimum exit proportion is 70%.

8. The composter of any one of claims 1 to 7 the minimum exit proportion is 80%.

9. The composter of any one of claims 1 to 8 wherein the first diameter is 100 mm.

10. The composter of any one of claims 1 to 8 wherein the first diameter is 125 mm.

11. The composter of any one of claims 1 to 10 wherein the second diameter is 250 mm.

12. The composter of any one of claims 1 to 10 wherein the second diameter is 200 mm.

13. The composter of any one of claims 1 to 12 wherein the housing floor slopes towards the outlet.

14. The composter of any one of claims 1 to 13 wherein an area of the housing floor as viewed in plan is at least twice of an area of the bottom of the basket as viewed in plan.

15. The composter of any one of claims 1 to 14 wherein the basket is dimensioned such that a smallest notional upright cuboid in which the basket fits hasP1912PCAU15 a smallest edge dimension and a largest edge dimension not more than 150% of a smallest of the edge dimensions; and a cuboid volume not more than 150% the basket volume.

16. The composter of claim 15 wherein the largest edge dimension is not more than 125% of a smallest of the edge dimensions.

17. The composter of any one of claims 1 to 16 wherein the basket volume is not more than 2,000 L.

18. A method of composting comprising lining the bottom of the basket of the composter of any one of claims 1 to 17 with compostable material to occlude the exit-openings; then supplying process material to the basket; then allowing the compostable material to compost to cause process material to fall through the exit-openings; then removing from the housing, and via the outlet, the process material that has fallen through the exit-openings.

19. The method of claim 18 wherein the compostable material comprises cardboard.

20. The method of claim 18 or 19 wherein the supplying process material comprises a household directly supplying the household’s kitchen scraps.

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