The present invention relates to a composting apparatus and method for the degradation of organic waste in soft or hard form.
The present invention utilizes a horizontal rotating drum in which organic waste material in hard or soft form is shredded and ground in a hopper before being introduced in an inlet opening of the drum which is constantly in rotation. Oxygen in the air surroundings of the drum is introduced therein through the hopper during normal use of the composter apparatus and surrounding air in an enclosure for the composter is exhausted. Such horizontal drum composters are known in the art but these known composters have several disadvantages in that many of these utilize screens to divide the drum into sub-composting compartments and the drums are oriented at an angle whereby the compost material can move from an inlet end to an outlet end during rotation of the drum. For the material to move through the compartments, it needs to decompose to pass through the screens and often the inlet end of the drum will clog up with material which backs up to the inlet end for the reason that the decomposition has not sufficiently taken place and cannot pass through the screens and backs up. The material also clogs the screens and requires constant servicing to unclog. Accordingly, these composters have not proven to be efficient.
Other rotating drum systems work with forced air through-flow and again are provided with sieves against which material to be treated is forced by suitable means such as screw conveyors. Many of these sieve walls have a large central opening. The sieves also have a common mesh size and this implies that no large size particles are present at the discharge side of the drum. Again, drum constructions have been found to be expensive to construct and require constant maintenance and repair due to sieve malfunction.
The treatment of organic waste material also often requires several manipulations for the disposal thereof. For example, organic waste is usually collected in large establishments such as food processing plants or large grocery stores where the organic waste is placed in special bins or bags and is picked up by transparent vehicles to be brought to a disposal site, such as a landfill where it may be buried. The cost of transporting and disposing large volumes of organic waste has escalated in recent years due to increase in labour cost and transportation costs. Such organic waste also is not put to valuable use such as for the fertilization of soil whereby to be recycled into nature. When organic waste is used as landfills, it is slowly decomposted and if such is buried while being contained in plastic bags, the decomposition will take much longer and contamination results due to the use of plastics material. The odors released from these sites are also a nuisance to the environment.
It is known to dispose organic waste from food handling facilities where the organic waste is firstly ground in a mill and mixed with water before being discharged into a storage tank which is buried into the ground next to the facility for storage purpose. Periodically a vehicle having a suction hose removes the waste from the storage tank and transports it to a disposal site where the waste material is tilled into the soil for decomposition by soil organisms. Such disposal systems are used in commercial applications.
It is a feature of the present invention to provide a composting apparatus and method which substantially overcomes the above-mentioned disadvantages of the prior art.
Another feature of the present invention is to provide a compositing apparatus which is compact, easy to use and empty, economical to construct, requires very little maintenance and which can compost soft and hard organic materials.
Another feature of the present invention is to provide a composting apparatus which may be constructed in different sizes to treat domestic organic material from multi-residence buildings, grocery stores and food processing plants of all sorts such, as meat or produce handling plants.
Another feature of the present invention is to provide a composting apparatus which uses a rotatable cylindrical drum, the inner digestion chamber of which can be substantially evacuated by suction.
Another feature of the present invention is to provide a composting apparatus which is totally integrated and which is transportable and can be moved to different sites.
Another feature of the present invention is to provide an improved composting method for composting organic waste material in soft and hard form.
According to the above features, from a broad aspect, the present invention provides a composting apparatus which comprises a cylindrical drum rotatably supported along a central longitudinal axis thereof. A drive means is provided for rotating the drum about the longitudinal axis. A hopper is integrated with the drum and provided at a feed end of the drum for receiving organic waste material. A material shredding mechanism and grinding mechanism is rotatably secured in the hopper for shredding and grinding the organic waste material and feeding same to an inlet opening of the drum. Two or more material mixing and conveying vane assemblies are secured in spaced-apart relationship in the drum and rotatable therewith. The material mixing and conveying vane assemblies define sub-composting compartments therebetween. One of the material mixing and conveying vane assemblies is positioned adjacent the inlet opening. Each of the material mixing and conveying vane assemblies have a cylindrical support securable to an inner face of the drum and a plurality of vanes are secured in spaced-apart relationship to the cylindrical support and project interiorly towards the central longitudinal axis of the drum and oriented at a common angle to mix, and continue to shred, and displace shredded and ground material from the inlet opening towards the rear end of the drum. Means is provided to vent the enclosure. Discharge means is provided to discharge the material from the drum.
According to a further broad aspect of the present invention there is provided a method of composting organic waste material and which comprises the steps of feeding the waste material in a hopper associated with a feed end of a cylindrical composting drum and wherein the waste material is directed for shredding and grounding by a combination of a toothed feeder shaft having a series of cutting teeth intermeshed with a plurality of cutting blades secured to a chopper shaft. The feeding shaft and chopper shaft are driven in counter-rotation. The shredded and ground organic waste material is ejected in an inlet opening at the feed end of the cylindrical drum which is rotated along a central longitudinal axis thereof. The shredded and ground organic waste material is mixed, further shredded and conveyed towards a rear end of the drum as the drum continuously rotates. The mixing and conveying is comprised by a plurality of vanes assemblies secured to an inner wall of the drum and spaced-apart from one another and rotatively driven with the drum. The organic waste material is discharged from the drum by suction.
A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which:
Referring now to the drawings and more particularly to
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The shredding and grinding mechanism 28 is herein comprised of a toothed feeder assembly 30 and a chopper assembly 31 which are intermeshed with one another and which will be described in detail later on.
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The pusher plates 51 are of simple construction and are comprised of a flat rectangular plate 53 having at opposed ends thereof transverse attachment flanges 54 provided with a hole therein for securement to one of the attachment holes 49 of the attachment plates 47. The pusher plates 51 are also oriented at an angle offset from adjacent attachment plates whereby to continuously eject shredded organic waste material into the inlet opening but in alternate fashion while the shaft rotates.
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The top edges 76 of the vanes are diagonally spaced-apart from one another to form a central opening 79 therebetween to oxygenate the waste material pushed therethrough by the vanes. The side edges 75 further cut and shred the material within the drum as it moves between the sub-composting compartments 36.
The discharge end 38 of the drum is provided with a suction line coupling 80 centrally of the drum to receive a suction hose from a transport vehicle (not shown). As the suction is applied, the drum is maintained in rotation at the same speed or higher speed controlled by the control panel 95 whereby material in the drum is conveyed towards the discharge end 38 of the drum towards the central opening of a rear conveying vane assembly 35″ secured adjacent the suction coupling 80 to provide removal of the waste material in the drum. The organic waste material towards the discharge end of the drum is obviously composted more than the material at the feed end of the drum. However, the material is transported for further composting or for use in facilities to collect the gas generated by the compost and to use it for combustion and the production of electricity or for use in an aerobic digester to create gas to feed a gas grid for all sorts of uses. As shown in
The detachable panels 14 provide access to the composting apparatus for servicing and repair. A fan 85 is secured to the top wall 86 of the enclosure and has a filter to filter odor and is surrounded by insulation 85′ for sound dampening. An exhaust flue 87 conducts the filtered odors from the interior 88 of the enclosure to atmosphere. The frame 13 is also mounted on wheels 90 for ease of displacement of the composting apparatus 10.
The control panel 95 is provided with switches and controls to place the composter in operation and to adjust the speed of the various motors depending on the size and application of the constructed composting apparatus. A sensor 96 is secured to the hopper to detect material fed into the hopper and feeds a signal to the control panel to automatically operate the material shredding and grinding mechanism for a predetermined period of time or cycle. The operating time of the shredding and grinding mechanism can also be used to predict the volume of material fed to the composter. The control panel provides local and remote signals indicative of the volume of waste material contained within the cylindrical drum 11 and the number of days in use after removal of its contents whereby to schedule the removal of the composted material in the composter.
Briefly summarizing the method of operation of the compositing apparatus, it comprises of feeding organic waste material 27 in a hopper 25 wherein the waste material is shredded and grounded by a combination of the toothed feeder assembly 30 which is provided with a series of cutting teeth which are intermeshed with a plurality of cutting blades secured to a chopper assembly 31. The feeder shaft and the chopper shaft are driven in counter-rotation. The chopper assembly is further provided with pusher plates 51 to push or eject the shredded and ground organic waste material in an inlet opening of the cylindrical drum which is rotated about its central longitudinal axis. The material is injected into a mixing and conveying vane assembly 35′ which is disposed immediately adjacent the inlet opening which mixes and conveys the waste material towards the rear end of the drum 11 as the drum rotates. It is pointed out that the drum speed is adjustable to the desired use of the drum and this rotation causes the solid waste material and liquid material to mix with one another while being further shredded by the vanes of the mixing and conveying assemblies 35′. The undulations in the inner surface of the drum also favour mixing of the solids and liquids. The organic waste material is discharged from the drum by suction as previously described. Oxygen is admitted into the drum through the hopper which is not a sealed unit and the gases produced inside the cylindrical drum which escape into the interior 88 of the enclosure are evacuated by the fan 85 to atmosphere.
It is pointed out that the composting apparatus of the present invention is a self-contained, fully integrated unit which is easily displaceable and does not require a separate storage tank or crusher which are usually permanent installations and sometimes require installation or occupy space within a building. The composting apparatus of the present invention is easily displaceable and easy to install. As previously mentioned, it has several uses and may be made constructed of different sizes to accommodate, for example, residential building structures having several units or grocery stores, etc. The housing may also have its panels painted with decorative designs and colors to suit its location of use. Being a self-contained unit, it is also easily transportable to different sites.
It is within the ambit of the present invention to cover any obvious modifications of the embodiment described herewith provided such modifications fall within the scope of the appended claims.