WO2007006070A1

WO2007006070A1 - Composting apparatus

Info

Publication number: WO2007006070A1
Application number: PCT/AU2005/001920
Authority: WO
Inventors: Michael Morrison
Original assignee: Compost Oven Pty Ltd
Current assignee: Compost Oven Pty Ltd
Priority date: 2005-07-12
Filing date: 2005-12-19
Publication date: 2007-01-18
Anticipated expiration: 2008-01-12

Abstract

A composting apparatus is disclosed which has a container (12) for containing a composting mass (11). A heat transfer device in the form of a coil (20) or helical rib (50) is provided for transferring heat from the hottest part of the composting mass throughout the composting mass to facilitate aerobic decomposition of the composting mass.

Description

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COMPOSTING APPARATUS

Field of the Invention

This invention relates to a composting apparatus for composting material.

Background of the invention

Composting is an environmentally friendly way of disposing of waste organic material. Generally, in order to provide good compost, it is desirable that the material aerobically decompose . By providing the right environment for aerobic decomposition, the material can quickly decompose and the quality of the compost is improved.

One problem with composting in containers is the dissipation of heat within the container to maintain good composting conditions, as well as the ability to provide air for aerobic decomposition.

Summary of the Invention

The object of the present invention is to provide a composting apparatus which addresses the above problem.

The invention provides a composting apparatus comprising: a composting container for receiving compostable material ; an air inlet in the container for providing air to the composting material to facilitate aerobic decomposition of the material; and a heat transfer device in the container for transferring heat generated by the composting mass throughout the composting mass .

Thus, by providing the heat transfer device, the heat conditions within the container can be made more homogenous so the composting mass is evenly heated whilst at the same time being supplied with air for aerobic decomposition. This provides extremely good conditions for composting and therefore a good compost product.

In one embodiment the heat transfer device comprises a coil located within the container and which, when the container is supplied with compostable material, is embedded in the compostable material, the coil containing a fluid so that when composting material decomposes, heat which is generated heats the fluid within the coil and by convection, the heat is transferred throughout the coil to in turn dissipate the heat throughout the composting material within the container .

In one embodiment the coil is arranged substantially centrally within the container.

In this embodiment the coil may be supported on an inner chamber .

In another embodiment the coil may be located adjacent a peripheral wall of the container.

Preferably the fluid comprises water.

Preferably the coil includes adjacent windings which are arranged at an inclined angle to the horizontal when the coil is located in the container so that heating of the fluid within the coil at one part of the coil allows the heat to rise by convection through the coil .

In another embodiment, the device may comprise both a centrally located coil and a peripherally located coil .

In this embodiment the peripherally located coil and centrally located coil may be coupled for fluid transfer between the coils . In a still further embodiment the device may comprise a helical rib adjacent the peripheral wall of the container and located in the container and extending between a base of the container and a top of the container .

In this embodiment the helical rib may be formed integral with the peripheral wall or connected to the peripheral wall.

In this embodiment the rib may have a width which varies from a relatively wide width near the base of the container to a relatively smaller width near the top of the container .

The rib may be provided with baffles so that air is forced to flow over the baffles to slow the passage of air between the base of the container and the top of the container .

Preferably the air inlet comprises an opening in the peripheral wall of the container.

In one embodiment the air inlet may comprise a tube extending from the peripheral wall to the inner chamber, and the inner chamber is provided with at least one opening for allowing air which flows through the tube into the chamber to exit the chamber into the compostable material .

Preferably the apparatus includes anti-compacting devices for preventing compaction of the compostable material to provide air spaces in the compostable material.

The container may be formed from any suitable rigid material such as plastics material.

In one specific embodiment the container includes a wall - A - configuration including reinforced bubble wrap material as disclosed in my co-pending Provisional Application No. 2005905860.

Preferably the container has a lid.

The lid may include a filter for filtering gases created by decomposition within the container before the gases exit the container.

Brief Description of the Drawings

Preferred embodiments of the invention will be described, by way of example, with reference to the accompanying drawings , in which: Figure 1 is a view of a composting apparatus according to one embodiment of the invention;

Figure 2 is a view of part of the apparatus showing a modification to the apparatus of Figure 1 ;

Figure 3 is a view of a further embodiment of the invention;

Figure 4 is a cross-sectional view along the line IV-IV of Figure 3;

Figure 5 is a perspective view from beneath of a lid used in the embodiment of Figure 3 ; Figure 6 is a view of a still further embodiment of the invention;

Figure 7 is a perspective view of part of the embodiment of Figure 6; and

Figure 8 is a cross-sectional view along the line VIII-VIII of Figure 6.

Detailed Description of the Preferred Embodiments With reference to Figure 1, a composting container 10 is shown which contains compostable material 11 in the form of organic material such as garden cuttings, waste food or the like. Additives may be added to the compostable material 11 to provide specific benefits, depending on the — R —

use of the material, such as trace minerals and the like if the composted material is to be used as soil, etc. The apparatus 10 has a container 12 which may be cylindrical or any other desired shape and which is defined by a peripheral wall 14 , a base 15 and a lid (not shown) .

In the embodiment of Figure 1 , an inner cylindrical chamber 16 is provided which has an air inlet tube 18 extending through the peripheral wall 14 to the exterior of the apparatus 10 so that air can enter the tube 18 and flow into the chamber 16.

A coil 20 is wrapped around the chamber 16 and has a helical section 21, a generally upright section 22, a lower tube 23 joining the upright section 22 to the helical section 21, and an upper tube 24 joining the helical section 21 to the upright section 22. The section 22 extends above the helical section 21 so that fluid such as water can be poured into the coil 20.

The upright tube 22 may be closed by a stopper 25 or may be left open.

As the material 11 begins to decompose, heat is generated. Generally, the hottest part of the composting mass is slightly above the base such as identified by point P in Figure 1. The material below the point P is generally fully composted and as fully composted material is removed from the bottom of the container 12 and new material is added through the top of the container 12, the heated region of the composting mass is pulled downwardly. Some heat will tend to rise up through the composting mass but, explained above, the hottest part of the composting mass will generally be at about the point P shown in Figure 1.

As heat is generated at point P, the heat generated heats up the fluid in the spiral coil 21 and also the air in the chamber 16. The heating of the fluid, such as water, in the tube 21 transfers the heat by convection up through the helical section 21, thereby transferring heat up through the composting mass 11 towards the top of the composting mass. The water which has cooled at the top of the helical section 21 is able to flow back into the tube 22 and circulate back down to the bottom tube 23 where it is reheated and again travels up through the spiral section 21 to transfer the heat from the hottest area P throughout the composting mass.

As previously mentioned, the hot fluid in the helical section 21 also heats the interior of the chamber 16 so that air which enters the chamber 16 is heated. The air in the chamber 16 exits through hole 27. Generally as the composting material 11 composts, it tends to shrink and therefore will move away from the chamber 16 and the interior surface of the wall 14 to form spaces 29 and 30, as shown in Figure 1. This provides an air space through which air can travel. It is preferable to maintain a fresh supply of composting material at the top of the container so that it effectively forms a plug to cover the chamber 16 and prevent the air from merely flowing up through the spaces 29 and 30 in a chimney like effect. Thus, the air which exits the hole 27 flows into the space 30 and will then dissipate through the composting material 11. Thus, the heated air which is provided to the composting material 11 and the transfer of heat by virtue of the helical section 21 provides ideal conditions for the composting of the material to thereby provide rapid composting and a good composted product.

The embodiment of Figure 1 may also include anti- compaction devices 31 which are in the form of spikes which pass through the wall 12. The spikes 31 prevent the compacting down of composting material and thereby provide a space 32 immediately below the spikes 31. These spaces also facilitate the flow of heated air through the composting mass to improve the aerobic decomposition of the composting material.

The embodiment of Figure 1 may also include an outer coil 33 (identified by only one spiral in Figure 1) . The coil 33 may be connected to the coil 20 or may be completely separate. The coil 33 also facilitates heat transfer throughout the mass 11. The coil 33 will be disclosed in more detail with reference to Figure 3.

Figure 2 shows an alternative form of chamber 16 and coil 20. In this embodiment, the chamber 16 is provided with a spiral groove 35 in which the coil section 21 locates. This facilitates fixing of the coil 20 relative to the chamber 16 and also close contact of the coil 20 and the chamber 16 for heat exchange with the air in the chamber 16.

As is apparent from Figure 1, the hole 27 is below the tube 23 so the air flow from the chamber 16 is below the coil 20 and therefore the air which makes it way into the composting mass 11 is superheated by two sources being heating within the chamber 16 and then heating by the coil 20 as the air passes up the space 30.

As previously mentioned, it is ideal to have the composting material cover the coil 20 and the chamber 16 so that air movement is forced to flow through the composting mass 11 and thus brings fresh oxygen to the composting mass .

The circulation of the heated water within the coil 20 also tends to bring some heat to the bottom of the composting mass below the point P thus maintaining good conditions at the bottom of the composting mass 11 for aerobic decomposition. The embodiment of Figure 1 generally relates to a domestic type composting apparatus .

Figure 3 shows an apparatus which may be used in commercial or larger scale composting environments . In this embodiment, the container 12 is a rotor moulded water tank. The container 12 may have an interior wall 12a which is formed from reinforced bubble material of the type disclosed in our aforesaid International application. In other embodiments , the entire wall 12 may be formed from reinforced bubble material with the reinforcing being on the exterior surface and formed from laminated steel or the like.

In this embodiment of the invention, the container 12 is provided with a hatch 40 which can be opened to enable composting material to be emptied from the bottom of the container 12. This embodiment utilises the coil 33 of Figure 1 which is provided adjacent the inner surface of the wall 12. The coil 33 operates in the same manner as the coil 20, with heated water circulating through the coil section 38 and through vertical section 39. This embodiment may or may not have the central coil 14 as in the embodiment of Figure 1. Again, anti-compaction devices 31 are provided for the same reason as described with reference to Figure 1.

In the large scale system of Figure 3 where material is removed from the hatch 4, probably on a daily basis, and new material added also on a daily basis , heat build-up will probably take a few days , whereas in the embodiment of Figure 1 , which is a much smaller environment and where material is removed less frequently, heat will probably build up to a maximum temperature within a few hours.

The system described with reference to Figures 1 and 3 enables small amounts of material such as soil, which normally drop the heat of the composting system, to be added with virtually no heat loss because of the heat transfer provided by the coil 20 or the coil 33. This is an important feature for pasteurising old soil or diseased material as well as killing seeds in animal manure .

In the embodiments of Figures 1 and 3 , the container 12 is preferably insulated to maintain heat within the container . The insulation may be provided by the reinforced bubble material previously described, or by additional insulating material located in the wall 14.

In the case of bubble material to form insulating material, the bubble material is preferably laminated with aluminium or cardboard and has square or six-sided air cells which further reduce heat loss, by removing air gaps inside the bubble structure.

The cross-sectional view in Figure 4 shows the coil 20 described with reference to Figure 1 (which is not shown in Figure 3) . If the chamber 16 and its air inlet tube 18 are not provided, air may be provided by way of air holes in the chamber 12 which may communicate with tubes (not shown) for directing the air towards the interior of the container 12.

Figure 5 shows a lid for the commercial embodiment shown in Figures 3 and 4. The lid has a disc shaped body 45 and a conical air filter 47. The filter 47 is a bio-filter so that gases which are created during the course of composting can pass through the filter 47 and exit the apparatus 10. The filter 47 removes odour from moist gases created during composting. The conical filter 47 is preferably formed from mesh material and contains mature compost which acts as the bio-filter medium. The moist gases which exit the container may be passed through a still (not shown) before passing through the filter 47 so that the moisture can be fed back to the composting material to maintain a good moisture content within the composting material .

In the embodiment of Figure 3 , a number of the containers 12 may be linked together so that heat generated by the composting material in one of the containers is used to support the breakdown of composting material in another of the containers . The various containers can be located up a slope to further enhance the sustained use of the heat as it rises to feed through the various composting containers .

Figures 6 to 8 show a still further embodiment of the invention in which, rather than using a coil as the heat transfer device, a helical rib 50 formed adjacent the inner periphery of the container wall 12a is used. Whilst the provision of the rib 50 adjacent the inner periphery of the container wall is preferred, the rib 50 may be spaced inwardly of the wall if desired. If the rib is located adjacent the wall, it may be integral with the wall 12a or otherwise attached to the wall 12a.

The rib 50 may have baffles 51 extending downwardly from its under-surface. The ribs 50 effectively forms an anti- compaction member which prevent the compaction of composting material just below the ribs 50. This therefore provides an air space below the ribs 50 which can be used to convey hot air from the hottest part of the composting mass upwardly through the composting material. The baffles 51 slow the flow of heated air as it rises beneath the rib 50, thereby facilitating movement of the heated air into the composting mass 11 within the container . As shown in Figure 8, the rib 50 changes in width from the bottom of the container 12 to the top of the container 12. At the bottom of the container 12, the rib 50 has a width Wl shown in Figure 7 and the width gradually decreases as the rib 50 spirals up the container during intermediate width W2 at the location of the cross-section which forms Figure 7 and to a smaller width at the top of the container shown in Figure 5.

The introduction of air into the container 12 may be by way of a chamber 16 of the type previously described or other air inlet tubes at the bottom of the container.

In the embodiment of Figure 1, a number of holes 27 (only one shown) may be provided up the length of the chamber 16 and some of the holes blocked depending on the temperature of air which is required and the flow characteristics of the air into the composting mass . The higher the hole in the chamber 16, the hotter the air which will be provided from the hole because the hot air will tend to rise to the top of the chamber 16 and the cooler air will tend to be at the lower part of the chamber 16.

In a still further embodiment (not shown) the spiral rib 50 may be motorised so that it rotates in the form of an auger to help the flow of air into the composting mass.

In still further embodiments, rather than provide a coil 20 on the chamber 16, the chamber 16 could be provided with a rib of the same type as the rib 50 shown in Figure 8. Whilst it is preferred that the rib be wider at the bottom and decrease in width towards the top of the container, the rib could be the same width throughout.

In still further embodiments, a tap may be provided at the bottom of the container for draining off any leachate which forms , or small holes can be provided in the base 15 .

Since modifications within the spirit and scope of the invention may readily be effected by persons skilled within the art, it is to be understood that this invention is not limited to the particular embodiment described by way of example hereinabove.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise", or variations such as "comprises" or "comprising", is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Claims

1. A composting apparatus comprising: a composting container for receiving compostable material / an air inlet in the container for providing air to the composting material to facilitate aerobic decomposition of the material; and a heat transfer device in the container for transferring heat generated by the composting mass throughout the composting mass .

2. The apparatus of claim 1 wherein the heat transfer device comprises a coil located within the container and which, when the container is supplied with compostable material, is embedded in the compostable material, the coil containing a fluid so that when composting material decomposes , heat which is generated heats the fluid within the coil and by convection, the heat is transferred throughout the coil to in turn dissipate the heat throughout the composting material within the container.

3. The apparatus of claim 2 wherein the coil is arranged substantially centrally within the container.

4. The apparatus of claim 3 wherein the coil is supported on an inner chamber.

5. The apparatus of claim 2 wherein the coil is located adjacent a peripheral wall of the container.

6. The apparatus of claim 2 wherein the fluid comprises water .

7. The apparatus of claim 2 wherein the coil includes adjacent windings which are arranged at an inclined angle to the horizontal when the coil is located in the container so that heating of the fluid within the coil at one part of the coil allows the heat to rise by convection through the coil .

8. The apparatus of claim 2 wherein the device comprises a centrally located coil and a peripherally located coil.

9. The apparatus of claim 8 wherein the peripherally located coil and centrally located coil are coupled for fluid transfer between the coils .

10. The apparatus of claim 1 wherein the device comprises a helical rib adjacent the peripheral wall of the container and located in the container and extending between a base of the container and a top of the container .

11. The apparatus of claim 10 wherein the helical rib is formed integral with the peripheral wall or connected to the peripheral wall .

12. The apparatus of claim 10 wherein the rib has a width which varies from a relatively wide width near the base of the container to a relatively smaller width near the top of the container.

13. The apparatus of claim 10 wherein the rib is provided with baffles so that air is forced to flow over the baffles to slow the passage of air between the base of the container and the top of the container .

14. The apparatus of claim 1 wherein the air inlet comprises an opening in the peripheral wall of the container .

15. The apparatus of claim 1 wherein the air inlet comprises a tube extending from the peripheral wall to the inner chamber, and the inner chamber is provided with at least one opening for allowing air which flows through the tube into the chamber to exit the chamber into the compostable material .

16. The apparatus of claim 1 wherein the apparatus includes anti-compacting devices for preventing compaction of the compostable material to provide air spaces in the compostable material.

17. The apparatus of claim 1 wherein the container has a lid.

18. The apparatus of claim 17 wherein the lid may include a filter for filtering gases created by decomposition within the container before the gases exit the container .