WO1994029240A1

WO1994029240A1 - Compost bin

Info

Publication number: WO1994029240A1
Application number: PCT/FI1994/000236
Authority: WO
Inventors: Ilkka Raita; Pertti Tammivuori
Original assignee: Ecora Oy Tara Finland Ltd.
Priority date: 1993-06-03
Filing date: 1994-06-03
Publication date: 1994-12-22
Also published as: FI1116U1; FIU930336U0; AU6846394A

Abstract

The compost bin includes a bottom section (1) and a cover section (2). At least the cover section (2) is designed as a partial spherical surface so as to create a spherical shape for the upper part of the compost bin, and the bottom section (1) converges from top to bottom.

Description

Compost bin

The present invention relates to a compost bin or a composter defined in the preamble of the appended claim 1 and intended for decomposing household, garden and toilet waste as well as other organic waste into soil.

Composting has been used by the mankind for milleniums. It has been used for converting waste into fertile nutrient-rich soil. At present, composting has also become a part of community garbage disposal; the organic co postable waste separated through sorting can be easily composted wherever the waste is produced. This results in substantial savings e.g. in waste transport costs and dump-site maintenance costs. Organic waste is the type decaying among other waste and thus loading the environment but, when separated and composted, it is a highly useful nutrient-rich soil improver.

In terms of composting household waste, various forms of composting is performed, e.g. as follows:

1) an open pile of compost, which is suitable for composting garden waste,

2) a compost cage, which is suitable for composting garden waste and, if protected from harmful animals, can also be used for composting household waste e.g. in summertime, and

3) a thermal composter, which is intended for the perennial composting of household, garden and toilet waste.

As for these various available types of composts, the thermal composter is the most advanced and useful in view of community waste disposal. As for their useful¬ ness and functional aspects, however, the thermal composters available on the market fail to fulfil e.g. the following conditions:

the composter must be readily loadable and un- loadable,

the composter must be capable of composting all the compostable waste produced by a single family,

- the composter must be capable of maintaining conditions favourable to composting under all varying circumstances independently of varying weather conditions or the filling or loading degree of a compost pile, and

in order to increase the popularity of composting, the composter must have a good value price and be attainable to all consumers.

In order to function, a compost requires oxygen contained in the air. The supply of oxygen must be secured in all circumstances and at the same time the thermal economy of a compost must be kept in proper order for creating optimal conditions for the decom- position of waste. In addition, a compost must be readily loadable and unloadable.

An object of the invention is to introduce a compost bin intended particularly for household application and creating optimal conditions for the decomposition of waste. In order to achieve this object, a compost bin of the invention is principally characterized by what is set forth in the characterizing clause of the appended claim^*1.

By virtue of a spherical compost bin shape, the composting can be effected with a favourable volume/ area ratio and other benefits described hereinbelow. The invention involves also improvements relating to air circulation and circulation of nutrients described hereinbelow.

The invention will now be described in detail with reference made to the accompanying drawings, in which

Fig. 1 shows a compost bin of the invention in section.

Fig. 2 is a front view of a compost bin of the invention,

Fig. 3 illustrates one possible surface design for a compost bin.

Fig. 4 shows a floor structure for the bottom section of a compost bin, and

Fig. 5 shows a structure for a loading or filling lid in section.

A compost bin of the invention is illustrated in Figs. 1 and 2. The compost bin includes a bottom section 1 supporting a decaying compost mass M and having a lowest part which is relatively flat for placing the compost bin firmly at a desired location.

On top of the bottom section 1 lies a cover section 2 for closing the open bottom section from above and for covering the compost mass M from above and the sides. In addition, on top of the cover section 2 lies a filling lid 3 for loading or charging that can be removed for providing an open charging hole at the top of the cover section in view of loading and inspecting the compost bin. The cover section 2 as a whole is also readily removable from top of the bottom section 1. The cross-sectional view of Fig. 1 il¬ lustrates how the cover section 2 includes a bottom rim provided with a bearing surface abutting against the top rim of the bottom section 1 and outwards of this bearing surface is a downwardly extending flange 2a for holding the cover section firmly in position. The cover section 2, together with the topmost filling lid 3, has the shape of a part of a spherical surface. The bottom section 1, with the exception of the lowermost flat floor, has likewise the shape of a part of a spherical surface. Thus, the compost bin is round, i.e. has the distinct shape of a partial spherical surface and a height which makes it easy to handle. The cover section 2 has the size of a hemi- sphere and forms the upper hemisphere of a globe and its height from the bottom rim to the highest point is more than half of the entire compost bin height. As the cover section is removed, the bottom section will be exposed over the entire compost bin width. The moisture and temperature conditions are favourable to composting, the cover section has a minimized surface area and angles and corner points are eliminated from the compost structure. The packing of mass caused by the depression of a waste mass is prevented by way of designing the bottom with the bottom section 1 converging downwards to terminate in a flat floor. Also the filling lid 3 can be designed in view of returning nutrient-rich condensing water to wherever it is desired, as described hereinbelow.

Figure 3 illustrates one possible surface design for the compost bin. The compost bin cover section 2 is patterned as a world map befitting the universal spherical shape of the compost bin. The map can be designed as an embossment in a desired fashion, e.g. by making use of the qualities of a plastic material used for the cover section 2. Figure 4 shows a floor structure of the invention, whereby the air coming in the compost along inlet ducts 4 is preheated in a space 5 between the warm compost mass and the ground. In Fig. 4, reference numeral 7 designates an actual base lying against the ground and included in the floor structure. The cold outside air is passed into the centrally located closed space 5 through ports opening laterally of the floor structure and along the closed inlet ducts 4 extending radially towards the centre. The duct system is used for prolonging air circulation in this inter¬ mediate space and, thus, the air is afforded a longer period of time to warm up. The air is evenly dis¬ tributed into the compost along ducts 6, which extend away from the space 5 and are perforated. The inlet ducts 4, the centrally located space 5 and the ducts 6 extending therefrom are located above the base 7 and can be open downwards, whereby the ducts can be closed from below by inserting a separate panel between the base 7 and the ground. The duct system also supplies automatically more air towards the outer rims, thus using, as the rims are cooling down, an automatically insulating warm air circulation to create supplementary insulation in the outer portion of the compost between the compost mass and the inner wall of the compost bin. For this purpose, the inner wall of the bottom sec¬ tion 1 can be designed as desired, e.g. by providing it with vertically extending projections and recesses (shown by dash-and-dot lines in Fig. 1) for facilitat- ing the passage of air. If necessary, the air circula¬ tion and thermal economy of a compost can be further improved by means of an electrical thermoelement, fitted in space 5 in the middle of the floor. The air circulation within the floor, air diffusion effected by the walls, and the air circulation control possi¬ bility provided by a control opening 8 included in the filling lid 3 can be used together for substan¬ tially improving the operation of a compost in colder winter conditions even with a less efective insulation.

The floor structure shown in Fig. 4 also maintains moisture in a compost more effectively. The period between compost watering times becomes longer and when the compost is watered, the floor maintains the liquid and moisture within the compost more effectively than what is achieved with a meshed or open floor. The compost need not be watered as often and the nutrients dissolving therein while filtering through the compost are kept effectively within the compost.

Figure 5 illustrates the structure of filling lid 3 in a vertical section. The filling lid 3 provides "a calotte" for the globe and it is laid on top of an opening included in the uppermost portion of the cover section 2, whereby it is positioned on top of the opening rims by means of a bearing surface included in the lid rim. Inwards of the bearing surface is located a downwards extending side wall 3a, which is positioned inside the upper rim of the opening for securing the lid in its position. In addition, the lid is designed in such a manner that its bottom wall 3b, i.e. the surface facing the compost, the central portion and edges extend further down than the rest of the surface, whereby the condensing water that condensates on the lid trickles to the center and edges and falls into the center of a compost and on an annular zone between the outer edge and the centre of the compost. One even more important feature of the filling lid is its box¬ like structure. Between the top wall 3c and the bottom wall 3b of the lid is a void 3d. The top wall 3c providing a cold outer wall serves as a condenser for the moist nutrient-rich gases rising from below into the void through ports 9 included in the lowermost points, i.e. in the center and edges, of the bottom wall and returns effectively moisture and nutrients to be exploited by the compost in the form of drops falling through said ports 9. The air circulation can be controlled by means of a valve included in the top wall 3c and determining the size of a control opening 8 letting air out of the interior of the compost bin through said filling lid.

The filling lid 3 can be removed for supplementing the compost and for inspecting its condition. The larger cover section 2 can be removed and, when turned upside down, it can be used as a sort of second container for carrying out the sorting of waste when emptying the compost. The waste that has not been decomposed at all can be replaced in the compost bin cover sec¬ tion 2 and the finished decomposed waste can be taken elsewhere. The sorting of waste contained in a compost must always be performed since, in a composting process, the decomposition of various types of waste varies in time and generally the compost bin has non- decomposed waste on top and more decomposed waste further down. The ready-for-use waste can be trans¬ ported for example in the container section 1 by carrying it by means of handles included therein.

By virtue of the floor structure and the condensation return effected by the lid the invention functions on a lesser amount of nutrients more effectively than the composts available on the market as it does not lose nutrients along with the irrigation water and the nutrients do not evaporate in the air along with moisture.

Hereinafter, a few more main priciples for a composting process will be explained, which principles can be carried out by means of a compost bin of the invention. In view of promoting the decomposition process and for a successful air circulation and exchange of gases, the thermal conditions of a compost are extreme¬ ly critical. The air circulation is based on a dif- ference of temperature within a compost, inside a compost bin as well as outside, since warm air rises upwards. The air circulation and thermal economy can be influenced e.g. as follows.

1. The compost container is thermally insulated in view of exploiting the process-delivered heat in a compost.

2. The air circulation of a compost is controllable, whereby the air circulated through a compost can be limited in colder conditions, e.g. in wintertime.

The control of air circulation is effected by regulating the ports for an outflowing air.

3. In order to secure the air circulation and thermal economy in winter conditions, the intake air to be delivered into a compost is heated against the warm bottom part of a compost mass. The air circulation can be intensified by means of a low-power heating resistance, which is placed in an air space in the middle of the floor. The overall air circulation is controlled by regulating air outlets and by controlling operation of the resistance by means of a thermostat placed in the air space of the compost bin.

4. The preheated air is delivered by way of a system of air ducts uniformly into a compost. Some of the air also finds its way onto the inner wall of the bottom section and will serve as an effective thermal insulation in cold conditions. In a composting process, the mass densities upon the decomposition of organic matter. In the invention, it has been structurally taken into consideration that the waste is packed in the bottom part of a compost and that the air circulation must be secured in all circumstances also into the upper portions of the compost by way of air ducts.

In view of the proper function of a compost, certain dimensions and forms are essential. When the function of a compost is based on biological bacterial action, the conditions, such as a nutrient content, moisture as well as thermal economy, must remain the same in various parts of a compost bin. This is why the compost bin is of a round design, i.e. it does not include cold or dryer corners and the shape has been designed by keeping in mind also the depression and compaction of a compost mass and the air circulation problems resulting therefrom. The compost bin design has considered a minimum surface area for a minimum evaporation of heat. Also the condensation and gasifi¬ cation on the lid of a compost bin is optimized and the condensated liquid returns in a controlled fashion into the central portion of a compost mass into the areas below the central part and edge of the filling lid in a compost in view of effectively spreading the same all over the compost.

It is obvious for a person skilled in the composting process that the invention is by no means limited to the described example but can vary within the scope of the appended claims. The compost bin can be made of a plastic material, for example by injection moulding from a highly heat insulating plastic, whereby the insulation of walls can be effected for example by using foamed polyethylene.

Claims

1. A compost bin, comprising a bottom section (1) and a cover section (2) , characterized in that at least the cover section (2) is designed as a partial spher¬ ical surface so as to create a spherical shape for the upper part of the compost bin.

2. A compost bin as set forth in claim 1, charac¬ terized in that the bottom section (2) converges from top to bottom and, thus, that section and the cover section (1) , when joined together, create a globe- resembling shape for the compost bin.

3. A compost bin as set forth in claim 2, charac¬ terized in that the bottom section (2) is designed as a partial spherical surface.

4. A compost bin as set forth in claim 1, 2 or 3, characterized in that the cover section (2) has a height which is more than half of the total height of the compost bin and the lowermost part of the bottom section (1) consists of a flat floor (7) .

5. A compost bin as set forth in claim 1, charac¬ terized in that the cover section (2) is provided with a global map.

6. A compost bin as set forth in any of claims 1-4, characterized in that the floor structure of said bottom section (1) includes an inlet air duct (4) which is extended into a space (5) , included in the middle of the floor structure and provided with ducts (6) extended towards the edges for distributing air into the compost bin.

7. A compost bin as set forth in claim 6, charac¬ terized in that the floor structure includes a plurality of inlet air ducts (4) which are extended radially from the edges into said space (5) in the middle.

8. A compost bin as set forth in any of the preceding claims, characterized in that one part of the cover section (2) consists of a removable filling lid (3) .

9. A compost bin as set forth in claim 8, charac¬ terized in that the filling lid (3) is of a box design, the lowest points of its bottom wall (3b) being provided with ports (9) for delivering the condensation water condensated on the inner surface of the top wall (3c) of the lid back into a compost mass (M) .