Composting device and method for composting waste

The present invention relates to a composting device comprising a compost container provided with a feed opening through which waste to be com- posted is added to the compost container.

The present invention also relates to a method for composting waste residing in the compost container of a composting device.

In this application, the term "composting device" refers to both a composter and composting toilets classified as dry toilets.

Furthermore, in this application the term "belt loop" refers to an endless belt- like means such as an endless belt, caterpillar band, caterpillar mat, con- veyor belt or the like.

PRIOR ART

In the prior art are known drum-shaped composting spaces of composting devices, which are usually round. These are functional solutions as such, but do, however, include some obvious shortcomings and problems. One problem is that their shape is usually limited to a round one. In addition, the drum is rigid and dirt collecting in it is difficult to clean. Moreover, their mechanisms for turning the compost mass are not very reliable, which means that the compost mass easily slides in the drum. Keeping the structures of the drum dry is difficult and insects, such as flies and mosquitoes, reproducing in the constantly humid drum are a major disadvantage in using these devices.

Other problems relating to drum-based composting devices are, for example, that the whole drum rotates, which means that it is difficult to fix attach-

ments to it, for example for liquid separation, and in addition that the filling degree of a composting device based on a drum is low, because the drum can only be filled about half full for the mass to be composted to become mixed when the drum is rotated.

The above disadvantages are avoided by means of the device and method according to the present invention. The device of the invention is more efficient and easier to clean than the composting devices currently on the market. The device according to the invention may be a composting toilet and/or a composter.

The composting device according to the invention is thus characterised in that the compost container comprises a belt loop circulating inside it for the purpose of turning, mixing and/or moving the waste to be composted. Corre- spondingly, the method according to the invention is characterised in that the compost mass is turned, mixed and/or moved by means of a belt loop circulating inside the compost container.

The advantages of the composting device according to the invention are as follows:

- the belt loop in the compost container can be made to bend in different directions, whereupon dry dirt will fall off

- by means of the belt loop, preferably a caterpillar band type belt loop, the compost mass turns and mixes in the compost container more reliably than in, for example, a drum-based composting device (e.g. a composting toilet)

- variation of the size and shape of the device is easier by means of the belt loop, for example, a caterpillar band, than in a solution based on a drum, for example

- by means of the belt loop, the composting space of the device can be filled with the waste to be composted more efficiently than in the drum-based solutions on the market

- the manufacture of the composting device (e.g. toilet) is inexpensive (small partial components may be used, whereby a variety of manufacturing techniques are available)

- a belt loop, for example in the form of a caterpillar band, is a solution which prevents the appearance of insects because maintaining the structure dry is easier than in known solutions as the circulation of air is easier to control

- in a drum-based composting device, the whole drum rotates, in the belt loop device of the invention (e.g. a toilet) the side walls remain stationary, thus making it easier to fix attachments, openings, scrapers, controls or the like on them, for example for the purpose of liquid separation, mass or air control, measuring devices or sensors

- a device based on a belt loop, for example a caterpillar band, is easy to insulate as the casings against the compost mass remain stationary in contrast to a drum, and arranging heating is also easier (a heating resistor may be fixed directly on the surface of the casing in contrast to a rotating drum)

- in a belt loop model (e.g. a caterpillar band model), the filling degree may be markedly higher than in a drum and thus the use of space is more efficient

- in a belt loop model, new waste or compost mass may be guided, that is, moved further away or to an essentially more preferable location than in a drum where the round shape restricts the controlling of the mass.

In a preferred embodiment of the composting device according to the invention, the belt loop in the device extends essentially over the whole width of the compost container and is guided by means of grooves or protrusions on the interior walls. In another preferred embodiment, the inside of the belt loop in the device limits a composting space in the compost container into which composting space the waste to be composted is led for composting. According to yet another preferred embodiment, the said belt loop comprises one or more openings aligning with the feed opening below the feed opening, through which the waste is able to fall into the composting space limited by the inside of the belt loop in the compost container.

The composting device according to the invention may preferably also be intended to be a composting toilet, in which case it is provided with a toilet seat.

According to yet another preferred embodiment, the belt in the belt loop of the device is of the caterpillar band type or smooth, grooved or provided with spikes, nodules or corresponding means on its exterior and/or interior for ensuring the mixing of the mass. It is also preferable to move the belt loop in the device by means of at least one pair of cogwheels or similar means. According to a preferred embodiment, the movement of the belt loop in the device is arranged to take place by means of an electric motor or manually. A composting device according to the invention may also comprise means for leading off liquids to separate them from solid waste.

The invention is described in greater detail in the following by means of an example, with reference to the accompanying Figure 1, which shows an embodiment of the composting device according to the invention in vertical cross-section. The example below should not, however, be understood as a limitation of the claims disclosed below.

EXAMPLE

Figure 1 shows a composting device, which is a composting toilet 1. The composting toilet 1 according to the example is a thermally insulated com- post container 3 with a capacity of about 30 litres, which is in this example essentially in the shape of a seat with a backrest (that is, essentially L- shaped in vertical cross-section). The compost container may also be of a different shape.

The actual composting space 16 inside the compost container 3 is bordered in the sideways direction by vertical, plane-like sidewalls, and in the upper, lower and end directions by the inner surface of the belt loop 6 circulating in the vicinity of the upper end 12, lower end 13, front end 14 and back end 15 of the compost container 3. The caterpillar band 6 is essentially of the same width as the compost container 3 and it is guided by a groove in the side- walls and pulled by means of a cogged pair of sheaves 8 on a joint shaft located at the top end of the compost container 3, near the upper end 12 in the "backrest". The compost container 3 thus extends essentially from under the toilet seat 2 to the top of the part forming the "backrest".

The belt loop according to the invention, which is in this example a caterpillar band 6, may be moved either by means of an electric motor or manually, e.g. by means of a crank handle. In the solution shown in Figure 1, the caterpillar band 6 is moved by means of an electric motor (not shown) in such a way that the motor power is transmitted to the cogged pair of sheaves 8 which pulls the caterpillar band forward after each time of use.

The caterpillar band 6 is provided with equally spaced openings so that the waste is able to fall through the opening 10 of the seat 2 through an opening 7 on the band aligned with it to the composting space 16 inside the compost container 3, that is, inside the caterpillar band loop 6, on the caterpillar band

section below the opening 7, which section may or may not comprise openings. Whether there are openings or not is not as such significant in this solution since the caterpillar band 6 follows the bottom of the compost container 3, whereby no significant amount of mass is able to enter between the caterpillar band 6 and the bottom of the compost container 3. According to the invention, the belt loop may also be completely without openings.

After each time of use, the caterpillar band 6 is moved (clockwise in the Figure), for example, by means of an electric motor, by one opening spacing so that the compost mass 17 will turn and on collapsing cover the new waste moving backwards (towards the back end 15) on the caterpillar band 6. At the same time, the already composted mass 17 is able to fall out of the compost container 3 through a discharge opening 9 in the side wall, into a collection tank 4, shaft, conveyor screw, conveyor belt or the like below it, or into another device similar to that of the invention.

The structure of the toilet seat 2 in the example case shown in Figure 1 is such that it separates liquid (urine) by having an opening 10 for solid waste at the back and a front opening 18 for conducting liquids through a drain trap to the discharge drain. The toilet seat 2 may also be provided with a valve (not shown) for preventing, for example, the entry of washing waters into the compost container 3 or the composting space 16.

The compost container 3 may also be equipped with a fan 20 and a heating resistor 21. The compost container 3 and the toilet seat 2 are enclosed by a frame (not shown) and the casing 22 of the upper part so that possible odours and accumulation of condensation water are in control.

The composting device may also be non-separating. This applies to both the composters and composting toilets according to the invention. In this case there may be a vent 19 in the upper part of the compost container 3, and in

its lower part additionally a separate discharge drain opening (not shown), sieve tube or similar means by which excess liquid can be discharged from the compost mass.

The composting device according to the invention, which is preferably in the form of a composter is also well-suited for composting plant waste and/or food waste. The composting device according to the invention may thus be used, for example, for composting plant waste from the garden as well as household waste.