The present invention relates to a device which allows food scraps to be composted, to obtain compost to be used as soil conditioner and to supply a kitchen with the biogas produced, the whole inside only one device , which is easily to be transported and used in case no network infrastructures are provided . Technical field

At the state of the art , there are known various methods for biogas production from food scraps at industrial level , and some methods for biogas production at home or little communities ' level as well .

CN209397207 describes a device comprising a food waste pre-treatment unit comprising a centri fuge , a middle temperature and a high temperature wet anaerobic digester, and an equipment to press and filter waste in order to dehydrate waste . The device produces biogas and organic fertili zer . JP2008284463A describes a recycl ing plant for food scraps able to produce fodder and biogas . CN111151562A describes a method of treatment for waste separation of rural home waste , in which kitchen waste are converted in fodder for farm animals while fodder excess and farm animals droppings go into the biogas digester to produce biogas and organic fertili zer . CN110495713 describes an eco- friendly mobile kitchen and a system for kitchen waste disposal provided with a waste disposal device .

These and other embodiments known at the state of the art describe devices and methods for wet waste conversion ( i . e . of food scraps ) .

Anyway, to the best of the current inventors ' knowledge , none of the devices known at the state of the art allows to convert in loco organic waste in fertili zer, composted soil conditioner and biogas , thus allowing the immediate re-use , in particular for food cooking aims .

A concept of a device called "Cyclical kitchen" ( intrastructures . net ) was also presented, which is configured to convert food scraps in gas and to make this gas directly available for food cooking . Anyway, this device does not comprise means to increase the gas pressure to be used for cooking . The device obj ect of the present invention, as it is shown in the following, is instead provided with a vacuum pump which increases the gas pressure conveyed towards the burners , so to obtain a suf ficiently high pressure to provide the burners with a flame suitable for cooking .

Yet , the device described in the j ust cited concept comprises a tank for the digestate which has to be moved and opened integrally in order that both the leachate ( i . e . the liquid separating from food scraps ) and solid digestate go out . This is obviously a very di f ficult operation to be carried out in an environment as a kitchen, in which high hygienic standards are required .

The device obj ect of the present invention, as described in detail , comprises instead a leachate collecting basin which can be easily extracted to eliminate the liquid leachate more simply . Moreover, since it is not needed to open the whole tank to extract the leachate but simply to extract the basin positioned under the waste containers , it is obtained also the ef fect of avoiding air inlet inside the tank containing organic waste , which would slow down the biogas production .

So , it is clear that all the industrial solutions for biogas production cannot be adapted to rural environments , or however to environments where there are no infrastructures available for the introduction of the produced biogas in the methane distribution network or however for its collection by means of tank wagons . Moreover, the industrial solutions for biogas production need the presence of widespread waste home collecting services , which in many areas are not present .

At the same time , in the same areas , there are no basic infrastructures as wel l , and so the possibility to cook is left to the usage of solid fuels ( such for example wood and coal ) , which are more pollutant and less ef ficient from an energy point of view .

Aim of the invention

Aim of the present invention is to provide a device for waste conversion in compost while recovering at the same time the produced biogas for reusing it for cooking aims , which is easily and economically usable in settings where there are no networks infrastructures .

According to another aim, the present invention provides an integrated composting device which comprises also a cooking surface and which is easily transportable, so that it is easily used in little communities ' kitchens .

Brief description of the invention The invention realizes the prefixed aims since it is a food scraps composting device comprising an outer shell (1) comprising an upper surface (12) provided with at least a cooker (13) supplied with the gas contained inside a storage tank (6) , characterized in that inside said shell (1) there are provided, enclosed inside a space hermetically separated from outside (14) : at least an extractable waste container (2) provided with a respective closing cap (21) which guarantees the air tightness when said container (2) is introduced inside said separated space (14) and with at least partially holed walls; at least a leachate accumulation basin (3) , positioned under said at least one waste container (2) and configured to collect liquids dropping from waste contained in said at least one container (2) and in that inside said outer shell (1) there are also contained: a separation tank (4) , installed in communication with said separated space (14) , a first nonreturn valve (41) being interposed between them; an accumulation tank (5) connected to said separation tank (4) , a second nonreturn valve (51) and a vacuum pump (52) , configured to keep the separation tank (4) under depression by extracting from the same the gases produced and by pumping them in the accumulation tank (5) , being interposed between them; a storage tank (6) connected to said accumulation tank (5) by means of a nonreturn valve (61) .

The invention will be now described with reference to the appended drawings which show a preferred and not limiting embodiment of the invention.

As it is shown in figure, the device according to the invention comprises an outer shell (1) , preferably but not limitingly of transportable kind. To such aim, the shell (1) can comprise wheels (10) and a towing hook.

The outer shell (1) comprises an upper surface (12) provided with at least a cooker (13) , and preferably a plurality of cookers.

The device is characterized in that inside said shell (1) there are provided, enclosed inside a space hermetically separated from outside (14) : at least a waste container (2) , and preferably a plurality of waste containers, configured to be extracted singularly from said space and provided with closing caps (21) which guarantee the air tightness when the waste containers are introduced inside the shell (1) . Preferably said space separated from outside (14) is insulated, i.e. it is provided with a thermal insulation outwards, and preferably said thermal insulation is shaped so to limit the empty space available around said waste containers.

The waste containers are provided with holed walls, so that once the scraps are introduced therein and the containers (2) are positioned inside the shell (1) , the gas produced from waste fermentation can go out from said containers (2) and go into the volume inside the space (14) containing them. Moreover, inside said space (14) at least a leachate accumulation basin (3) is provided, positioned under said containers (2) and configured to collect liquids which possibly drop from the waste in fermentation step.

Also said basin (13) can be conveniently extracted singularly from said space (14) , and is configured so to reach air tightness when introduced in place. Preferably, the introduction mode of waste containers (2) and leachate basin (3) occur by sliding relative to the front surface (14) of the outer shell (1) , and to such aim the shell (1) is provided with respective sliding guides to make the introduction and extraction of said containers easy .

Preferably, also, said waste containers (2) are cylindrical in shape, and are configured to be rotated around their own axis, without the need to be extracted from the shell, by a manual action on the respective cap (21) .

Inside said outer shell (1) there are also contained: a separation tank (4) , an accumulation tank (5) and a storage tank (6) , configured as described in the following.

The separation tank (4) is in communication with said space (14) enclosing the waste containers, and a nonreturn valve (41) is interposed between them. The accumulation tank (5) is connected to said separation tank (4) , and a second nonreturn valve (51) and a vacuum pump (52) , configured to keep the separation tank (4) under depression by extracting from the same the gases produced and by pumping them in the accumulation tank (5) , are interposed between them.

The accumulation tank is connected to said storage tank (6) by means of a nonreturn valve.

Preferably, also, the outer shell (1) is provided with an aeration grid (17) to avoid inside the same the formation of explosive atmosphere after gas leak caused by leakage or malfunctioning.

The functioning of the system is described in the following .

Scraps are introduced in at least one of the waste containers (2) . After introducing scraps and closing hermetically the space (14) containing them, the action of the pump (52) , by putting the separation tank (4) under depression, allows the little overpressure generated by the waste fermentation (2) to win the resistance of the valve (41) separating the space (14) of the containers from the separation tank. At the same time, the action of the pump (52) displaces all the biogas produced in the accumulation tank (5) . When the gas pressure in the accumulation tank (5) is higher than the gas pressure in the storage tank (6) , the gas passes from the first one to the second one. The reverse path is hindered by the second nonreturn valve (51) .

Therefore, over time all the gas produced accumulates inside the storage tank (6) , from which it can be withdrawn to be burned in the cooker (13) . After a time interval defined relative to the introduction of waste in the respective container (2) , the same can be extracted and emptied of the compost contained therein and obtained from the waste fermentation which can be used as fertilizer, as well as the liquid contained in the accumulation basin (3) . The container (2) can be reloaded with new food scraps, and the cycle can be repeated. Each container can be loaded with new scraps at intervals equal to the duration of the treatment cycle. In presence of many containers, the system as a whole can be loaded at closer time intervals, by loading the various containers sequentially. Preferably, moreover, the system comprises a photovoltaic module (7) and a respective battery, configured to store the energy needed for the functioning of the vacuum pump (52) . In this case, the device can function in total absence of network infrastructures .

Preferably, but not limitingly the device comprises also means for heating the air contained inside said space ( 14 ) .

In a first embodiment, said means comprise an electric resistance (22) ; in another embodiment said means comprise an outer plate (16) , positioned on the rear side (16) of the outer shell (1) and provided with projections crossing the insulation of the space (14) and exchanging heat with at least one of the metal walls defining said space.

Conveniently, said plate is movable between a first position and a second position of removable type, so that it can function only in the time intervals in which said plate is exposed to the sun, and so, its thermal contribution is positive.

Moreover, preferably, the device comprises a control panel (9) , on which the values, detected by one or more sensors monitoring the device state, are visualized. These sensors can comprise one or more between the following ones: temperature sensor inside the space (14) containing the waste containers (2) ; pressure sensor inside the storage tank (6) ; temperature sensor of the cooktop (8) ; battery charge sensor; temperature sensor of the outer plate (16) .

In a preferred embodiment, the device comprises also hooking means (18) for fastening the device to a railing or other similar surface, configured to put said outer plate (16) in contact with said railing or similar surface.

In this way it is possible to exploit the heat accumulated from the outer surface after sun irradiation .