Composting device

Abstract

This composting device comprises a receiving tank (4) intended to receive the waste to be composted, said receiving tank (4) being provided with an orifice for discharging the compost resulting from the transformation of the waste within said receiving tank (4), and receiving an endless screw (11) positioned substantially at the bottom of said receiving tank and able to ensure the progression of the compost towards said waste discharge orifice. It also comprises a member (12) for stirring the waste, positioned within the receiving tank (4) above the endless screw (11) and consisting of a rotary shaft on which are mounted stirring means (15) extending radially with respect to said rotary shaft, the rotary shaft of the stirring member (12) extending parallel to the axis of rotation of the endless screw (11).

Description

[0001] COMPOSTING DEVICE

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a composting device, more particularly intended for collective or professional use, such as in particular intended for collective or commercial catering, canteens, collective buildings, EHPADs, fruit and vegetable shops, etc., in general for any producer of organic waste also called biowaste.

[0004] The aim of this device is not only to enable waste to be treated on site, but also to optimise the composting process itself.

[0005] PRIOR STATE OF THE ART

[0006] Composting is an aerobic biological process of converting and recovering organic matter into a stabilized, hygienic product, traditionally called compost.

[0007] In the case of this composting, organic waste is degraded in the presence of oxygen in the air and moisture in the materials, by the combined action of bacteria, fungi, micro-organisms and macro-organisms, in a few weeks or even months depending on the method used. This is a technique that is widely used today.

[0008] In fact, composting devices have been developed to accelerate the composting process, particularly in the context of collective composting or from professional producer landfills, which are therefore called upon to receive relatively large quantities of waste on a daily basis. To this end, tanks of appropriate dimensions have been proposed, intended to receive organic waste, and more particularly integrating a grinder capable of shredding said waste. The waste is ground and mixed using a stirring device, in such a way as to ensure and force oxygenation, thus optimizing the work of the bacteria naturally present in the biowaste.

[0009] At the end of the process, which typically lasts around four weeks, the waste transformed into pre-compost can be recovered and stored for a few weeks for maturation, then standardized and recycled into compost.

[0010] Although such devices have demonstrated their effectiveness in terms of quantitative transformation, a difficult transformation is observed, which may also be accompanied by nauseating fumes at the start of the process, implying the need to install a waste grinder upstream of the actual composting device, with the aim of ensuring biological and sanitary efficiency in the composting process.

[0011] The objective sought by the present invention is, on the one hand, to optimize the transformation of waste within the tank, and on the other hand to reduce the transformation time of said waste, also to simplify the design and production of such a composting device, and finally, to reduce the corresponding costs.

[0012] STATEMENT OF THE INVENTION

[0013] The invention therefore relates to a composting device comprising a receiving bin intended to receive the waste to be composted, said receiving bin being provided with an orifice for discharging the compost resulting from the transformation of the waste within said receiving bin. The receiving bin also comprises a worm positioned substantially at the bottom of the receiving bin, and capable of ensuring the progression of the compost towards a waste discharge orifice. According to the invention, the composting device also comprises a waste stirring member, positioned above the worm, and consisting of a rotary axis on which stirring means are mounted, extending radially relative to said axis, the rotary axis of the stirring member extending parallel to the axis of rotation of the worm.

[0014] In doing so, due to the respective rotation of the worm screw on the one hand and the mixing member on the other hand, efficient mixing of the waste is ensured, leading to an optimized mixing of said waste during composting within the receiving bin.

[0015] Furthermore, by printing a specific sequencing for the activation of these elements, that is to say alternating periodic mixing, and in particular, by imposing a change in the direction of rotation of the worm screw and the mixing member, typically every minute for a period of 5 minutes, and this, according to a periodicity of two hours, not only is the aeration of the waste optimized, but in addition, any accumulation or amalgamation of the waste in a localized place in the receiving bin is avoided.

[0016] Furthermore, and in order to optimize the cutting of the waste, the device also comprises knives, the latter being able to be fixed and integral with the receiving bin, or removable, and for example, extending vertically between the respective axes of the worm screw and the stirring member. These knives are advantageously positioned close to the respective lateral faces defining the receiving bin.

[0017] For this same purpose, the two ends of the worm screw are each also equipped with a radially oriented cutting blade, intended to cooperate with the knives mentioned in the previous paragraph.

[0018] The respective direction of rotation of the auger and the stirring member may be antagonistic in order to optimize the efficiency of the mixing of the waste, the direction of rotation being able to be alternated more or less periodically during the composting process. Experience shows that this continuous and circular movement of the waste within the area of ​​the receiving bin not only allows the waste to be sufficiently aerated to facilitate the composting process, but also ensures that larger waste is shredded and then crumbled, again capable of promoting the composting process.

[0019] According to an advantageous characteristic of the invention, the composting device also comprises a receptacle for carbonaceous materials and in particular for shredded material, typically consisting of wood chips of a few millimeters, in communication with the receiving bin, typically by means of a pivoting flap provided at the bottom of said receptacle. This receptacle is advantageously provided with an endless screw, the axis of rotation of which is oriented parallel to the respective axis of rotation of the endless screw of the receiving bin and of the stirring member.

[0020] Advantageously, the receiving bin is heated, and for this purpose, an electrical resistance extends at the bottom and at least part of the side walls of the receiving bin, so as to maintain in the volume defined by said receiving bin a temperature of between 20 and 45°C. Coupled further with a moisture extraction device, typically consisting of a fan, the excess moisture in the waste is reduced and an ideal temperature is available for the micro-organisms, again making it possible to accelerate the decomposition of the waste.

[0021] Advantageously, the rotation of the two axes, respectively of the worm screw and the stirring member, is carried out by means of a single motor or geared motor actuating a gear, the toothed wheels of which typically rotate at identical speeds. Furthermore, it may be envisaged that the rotation of the worm screw of the receptacle for receiving the carbonaceous materials (ground material) is also ensured by a pinion meshing with the upper part of the toothed wheel of the aforementioned gear, but rotating at a higher speed due to the size of the pinion, and typically at a speed doubled compared to that of the worm screw and the stirring member positioned within the receiving tank, and making it possible to ensure a regular and proportionate supply of carbonaceous materials within the receiving tank. BRIEF DESCRIPTION OF THE FIGURES

[0022] The manner in which the invention can be implemented and the advantages which result therefrom will emerge more clearly from the following example of implementation, given for informational and non-limiting purposes, with the support of the appended figures.

[0023] Figure 1 is a schematic perspective representation of the entire composting device according to the invention.

[0024] Figure 2 is an exploded perspective schematic representation of the device of Figure 1.

[0025] Figure 3 is a more detailed schematic representation of part of Figure 2.

[0026] Figure 4 is a schematic view of Figure 3 from another angle.

[0027] Figure 5 is a schematic representation illustrating the activation of the rotating members of the device of the invention.

[0028] Figure 6 is a more detailed schematic representation of a portion of Figure 5. Figure 7 is a schematic perspective representation illustrating the heating means associated with the receiving tray of the device of the invention.

[0029] Figure 8 is a more detailed schematic perspective view of the upper part of the device of the invention.

[0030] Figure 9 is a schematic representation similar to Figure 8, without the endless screw with which the crushed material receptacle is provided.

[0031] Figures 10 and 11 are schematic exploded perspective representations of the receiving tray of the invention viewed from two different angles.

[0032] Figures 12 and 13 are detail views of Figures 10 and 11.

[0033] DETAILED DESCRIPTION OF THE INVENTION

[0034] Figure 1 schematically shows the composting device (1) according to the invention. This comprises a frame or chassis (2), resting on casters (3), suitable for giving it a certain mobility. It incorporates a receiving bin (4), typically made of stainless steel, and intended to receive the waste. The latter are loaded into the receiving bin (4) in the upper part, the latter being equipped with a hinged folding flap (5) providing access to said receiving bin (4). Figures 1 and 2 also show an electrical box (6) equipped with its control panel (7), intended to ensure the operation of the device. Within said box (6), appears in Figure 1 an electric motor (8), intended to ensure the various functions, in particular mechanical, necessary for the operation of the device of the invention, which will be discussed in detail later.

[0035] Finally, also appearing in Figure 1 in particular, is a receptacle (9) for shredded material, and generally for carbonaceous materials. These carbonaceous materials are advantageously made up of wood chips of a few millimeters, calibrated so as not to affect the operation of the endless screw (26) that said receptacle (9) integrates. These carbonaceous materials are intended to be conveyed into the receiving bin (4) by passing through a slot (28), the width of which can be adjusted (see Figures 8 and 9). These carbonaceous materials are intended to promote the composting process.

[0036] In Figures 1 to 5, two essential elements of the device of the invention also appear, namely a worm screw (11) and a stirring member (12).

[0037] As can be seen in these figures, these two elements are rotatable, their respective axis of rotation being parallel to each other and typically horizontal or substantially horizontal, said axes of rotation being positioned directly above each other, substantially in the same vertical plane.

[0038] More precisely, the worm screw (11) is positioned at the bottom of the receiving tank (4), the edges of the threads of said screw being tangent to the bottom of said receiving tank (4) with the clearance close, the latter adopting precisely in the vicinity of the bottom a substantially cylindrical shape.

[0039] The purpose of this worm screw (11) is, on the one hand, to ensure, in cooperation with the stirring member (12), the mixing of the waste contained in the receiving bin (4), and on the other hand, to ensure the progression of the compost then located at the bottom of the receiving bin (4) towards a compost discharge orifice (13), the latter being closable by means of an articulated flap (14). The stirring member (12) comprises a certain number of stirring blades (15), substantially regularly distributed along the axis of rotation of said stirring member, capable of promoting the stirring and therefore the mixing of the waste, in cooperation with the worm screw (11). These substantially flat blades extend radially from the axis of rotation of said stirring member.

[0040] Furthermore, and in order to ensure the cutting of large waste, such as whole fruits or vegetables, the device of the invention comprises two knives (17, 17') extending substantially vertically. In the example described in Figure 6, these knives (17) are fixed, and in this case, respectively secured to the terminal or downstream side wall (18) partially defining the receiving tray (4) and to the internal face of the closing flap (14) of the discharge orifice (13). Alternatively, and according to another embodiment, these knives may be removable or not, and extend, again vertically, between the endless screw (11) and the stirring member (12), respectively positioned (17) in the vicinity of the downstream side face (18), and (17') in the vicinity of the upstream side face (18') of the receiving tray.These knives are intended either to cooperate with the blades (15) of the stirring member (12), or with two cutting blades (19, 19'), extending radially from the axis of rotation of the endless screw (11), and positioned substantially at the upstream and downstream ends of said endless screw (see figures 12, 13). This promotes the effective cutting of large waste, such as whole fruits or vegetables.

[0041] These different elements, whether the worm screw (11), the stirring member (12) and these functional elements (15, 17, 17', 19, 19') are, again advantageously, made of stainless steel.

[0042] The receiving bin (4) also comprises a discharge orifice (20) for the juices resulting from the composting operation, positioned in the vicinity of the discharge orifice (13) for the compost, as can be clearly seen in Figures 2 and 3. As can be seen in Figures 3 and 4, the rotation of the worm screw (11) and the stirring member (12) respectively is ensured by means of two toothed wheels (21) and (22) each meshing with the pinion (23) secured to the rotation shaft (output) of the motor or geared motor (8). In this case, the toothed wheels (21) and (22) being of the same diameter on the one hand, and comprising the same number of teeth on the other hand, they rotate at the same speed, and in the example described, in the same direction of rotation. In doing so, the stirring of the waste contained in the receiving bin (4) is optimized.

[0043] According to another characteristic of the invention, the receiving tray (4) comprises in the vicinity of its bottom a heating member (24). In the example described, this heating member consists of an electrical resistance wound in a mica support, itself positioned between two mica plates, in turn closed between plates made of stainless steel. This assembly is then shaped to the desired diameter, in this case to the external diameter of the substantially semi-cylindrical bottom of the receiving tray (4). This assembly is then fixed, for example by screwing, against the external face of said bottom of the receiving tray (4).

[0044] The heating power is relatively low, typically around 1 W:cm 2 , and a thermostat, whose probe is fixed to the resistance, ensures programmable regulation for a temperature limit set between 40 and 60°C.

[0045] In doing so, a temperature of the order of 20 to 45°C is maintained in the receiving bin, which is suitable for promoting the composting phenomenon and, in addition, for partially eliminating the moisture present in the waste. Moreover, this moisture removal is optimized by the presence of a moisture extractor (25), provided in the cover (5) closing said receiving bin, and typically in this case consisting of a fan.

[0046] Furthermore, and in order to optimize the composting process, it may be advantageous to integrate carbonaceous material and typically ground material with the waste. This is received in the receptacle (9) positioned, as already mentioned, on the upper part of the device, as can be clearly seen in particular in Figures 1, 8 and 9. This receptacle (9) is also equipped with a carbonaceous material feed screw (26), the rotation of which is advantageously ensured by the upper toothed wheel (22) actuating the rotation of the stirring member (12). For this purpose, the end of the rotation axis of the worm screw (26) is equipped with a pinion (27) which meshes with the toothed wheel (22). This worm screw (26) ensures a regular supply of ground material to the receiving bin (4), promoting the production of compost.

[0047] This receptacle (9) has a V-shaped bottom, the point (28) of which defines a slot of adjustable width, so as to obtain a regular and sufficient supply of shredded waste.

[0048] Typically, the rotation of these three rotating elements, respectively the worm screw (11), the stirring member (12) and the ground material feed screw (26) is programmed to operate typically for five minutes every two hours. During these five minutes of operation, the direction of rotation of each of these rotating elements, due to the cooperation of the toothed wheels which actuate them, reverses every minute. Here again, the aim is to optimize grinding, mixing and, as a corollary, composting.

[0049] Advantageously, the different stages of producing this compost are automated, using a programmable controller for example, particularly in terms of rotation sequences of the rotating parts, the duration of these rotations, the rise in temperature, and the extraction of moisture.

[0050] In the example described, the various active constituents of the composting device of the invention are indicated as being made of stainless steel. These elements are covered in a general frame (2), typically made of plastic, and for example of polypropylene, in particular by rotational molding. The whole interest of the invention is understood, which makes it possible to have a medium-scale composting device in terms of volume, in this case capable of having capacities of 150, 300, or even 600 liters, particularly suited to collective catering, local and territorial communities, and making it possible to ensure, in a relatively short time, the obtaining of quality compost. In addition, such a device proves to have a particularly low manufacturing cost.

[0051] Finally, such a composting device allows for a weekly production cycle, mainly due to the combination of alternating periodic mixing, heating, and ventilation.

Claims

CLAIMS 1. Composting device (1) comprising a receiving bin (4) intended to receive the waste to be composted, said receiving bin (4) being provided with an evacuation orifice (13) for the compost resulting from the transformation of the waste within said receiving bin (4), and receiving: • an endless screw (11) positioned substantially at the bottom of said receiving bin, and capable of ensuring the progression of the compost towards said waste evacuation orifice (13), and • a waste mixing member (12), positioned within the receiving bin (4) above the endless screw (11), and consisting of a rotary axis on which are mounted mixing means (15) extending radially relative to said rotary axis, the rotary axis of the mixing member (12) extending parallel to the axis of rotation of the endless screw (11), characterized: • in that it also comprises two knives (17, 17') extending vertically between the respective rotary axes of the worm screw (11) and the stirring member (12), intended to cooperate with two cutting blades (19, 19'), extending radially from the axis of rotation of said worm screw (11), and positioned substantially at the upstream and downstream ends of the latter; • and in that the direction of rotation of the worm screw (11) and the stirring member (12) are alternated more or less periodically and at regular intervals during the composting process.

2. Composting device according to claim 1, characterized in that it also comprises a receptacle (9) for carbonaceous materials and in particular for ground material in communication with the receiving bin (4).

3. Composting device according to claim 2, characterized in that the receptacle (9) is provided with a worm screw (26), the axis of rotation of which is oriented parallel to the respective axis of rotation of the worm screw (11) and of the stirring member (12).

4. Composting device according to one of claims 1 to 3, characterized in that the receiving bin (4) is provided with a heating member (24), extending at the level of the bottom and at least part of the side walls of said receiving bin.

5. Composting device according to one of claims 1 to 4, characterized in that it comprises a moisture extraction device (25), in particular consisting of a fan.

6. Composting device according to one of claims 1 to 5, characterized in that the rotation of the two axes, respectively of the endless screw (11) and of the member (12) of mixing is carried out by means of a motor or geared motor (8) actuating a gear, the toothed wheels (21, 22) of which rotate at identical speeds.

7. Composting device according to claim 6, characterized in that the rotation of the worm screw (26) of the receptacle (9) for receiving the carbonaceous materials or ground material is ensured by means of a pinion (27) meshing with the upper part of the toothed wheel (22).

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