1. Field of the Invention
The present invention relates to an apparatus and method for “vermin” (worm)-decomposition of biodegradable organic materials such as yard waste, waste paper, food waste, and the like. Worm composting requires special requirements in order that the decomposition apparatus and methods do not harm the worms. Mechanical stresses, temperature, aeration, waste type, and the amount of moisture can all affect the health of the worms.
For many years, it has been common practice for gardeners to make compost from leaves, grass clippings, food waste and the like. The material is generally placed in a pile or in a compost bin, which is then periodically agitated. Over a period of time, the organic material will naturally decompose becoming converted into nutrient rich humus. The resulting humus material is extremely beneficial to gardeners as the material can be mixed with soil or spread over the existing soil to provide a protective plant covering, reducing evaporation and protecting plants from heat and cold and also enhances the fertility and porosity existing soil. The compost covering also promotes germination of seeds and plants. Composting is attractive to gardeners for these benefits and further because composting reduces the volume of household waste that is deposited into landfills. Worm decomposition also adds the ability to form “worm tea” that has advantages of its own; like protecting the plants from insects, disease, while also working as a foliar feed, and supplement for soil and plants.
Composting basically is a controlled biological decomposition of organic material under aerobic conditions. The process relies on naturally occurring microorganisms, mainly bacteria and fungi, to break down organic compounds into simpler substances.
2. Description of Related Art
Several methods of composting are used today, either on a small-scale basis by individuals or in larger operations where commercial operators and municipalities conduct waste management facilities. The art of decomposition without use of worms does not apply to vermicomposting and the art relating to apparatus for decomposition without worms likewise does not generally apply to worm decomposition. In-vessel composting is known. In-vessel composting devices offer some advantages including better process control, higher rate decomposition and better odor control. Odor control is a major concern of composting systems. Various in-vessel composting and other type units and other systems can be found in the prior art patents. However, the art does not appreciate the issues and problems involved in vermicomposting. Vermicomposting is essentially the consumption of organic materials by special earthworms known as “red wiggler” worms. The end product is nutrient rich and is called vermicompost in the form of vermicompost and worm castings. When expelled from the worms, worm casts consist of granules surrounded by mucus that hardens upon exposure to air. These granules when mixed into soil slowly organic nutrients. The hardened particles do not readily breakdown so they serve to break up soils providing aeration and improved drainage. Worm tea, which is also rich in nutrients, can also be formed during the vermicompositing process. The most common red wiggler worms (Eisenia fetida and Lumbricus rubellus) put out a by-product called castings. Worm tea is obtained as water runs off or drips through the castings picking up the nutrients of the castings. Aerating also know as brewing will help the beneficial bacteria flourish for putting onto the plants or soil. Worm tea is infinitely richer in nitrogen, phosphate, calcium, magnesium and potash then the upper 6 inches of top soil. Worm tea is not only an organic plant food but it is also a natural repellent for aphids, spider mites, scale and white flies. This product will not kill insects, but repels them with a smell not detected by the human nose. Worm tea is also good for covering large areas such as lawns, orchards, gardens, etc.
The following United States patents teach various methods and apparatus for producing vermicompost: U.S. Pat. Nos. 6,155,447; 6,223,687; 7,029,512; 7,141,169; 7,879,600; 7,964,385 and 7,998,728. It should be noted that none of these patents teach use of rotating vermicomposter apparatus. The following United States patents teach various composting apparatus but for several reasons are not suitable for effective vermicomposting: U.S. Pat. Nos. 3,138,447; 4,193,786; 4,633,535; 5,139,554; 5,244,804; 5,254,472; 5,300,438; 5,661,031; 5,843,769; 6,001,641; 6,071,740; 6,351,855; 7,341,391; 7,371,566; 7,611,891; 7,745,208. Currently a functional all encompassing vermicomposting system was not known. At the present time the process of vermicomposting and separating waste into finished product is done in multiple operations utilizing various types of equipment such as worm beds, worm wigwams, can-o-worms, worm tea collection filtering and aeration, drying beds and a vermicomposting and vermicasting separation mill. The worm bed is a simple concept where waste is composted in wooden beds. These systems incorporate an automated irrigation supply while also having a worm tea collection feature.
Another system, the worm wigwan uses a simple cylinder in which fresh waste is loaded from the top. Worms reside on the top layer where vermicomposting occurs. When the compost is broken down it falls through a grating where it is collected. A third vermicomposting system, the Can-O-Worms, is a smaller scale design of the cylinder system described in the previous paragraph, in which multiple trays are stacked upon each other and fresh waste is loaded and manually irrigated from the top. The bottom tray consists of finished compost and is removed when full, emptied, placed on the top, and then filled with fresh waste to start the process over. This constant cycle utilizes the worm's tendency to migrate to fresh food requiring monitoring and manual labor often.
While the above-described apparatus and methods for composting and for the utilization and decomposition of waste organics are known, such apparatus and methods have not gained large acceptance by homeowners and industrial users for various reasons. The prior systems generally require substantial attention, as for example, the homeowner must periodically turn the material manually in a drum. The devices found in the prior art also often emit objectionable odors and attract flies and other insects. These variables often lead to human management error.
Thus, there exists a need for a simple, effective and highly efficient vermicomposting system, which may be utilized, both by the individual gardener or homeowner and also which may be used on a larger scale for municipal and commercial waste treatment systems.
Briefly, the present invention comprehends a composter for residential and commercial use having a circular conduit vessel (inner conduit) within a second circular conduit vessel (outer vessel) that is rotatably mounted while the common the axis of the vessels is tilted a few degrees up from horizontal. The inner vessel receives the organic material, worms and water as required. In one embodiment, the vessel is formed from a corrugated pipe so the corrugations move the material along through the vessel. The vessels are rotated at a preselected speed using a motorized drive sprocket engages a circumferentially extending track on the outer vessel. The apparatus is capable of continuous use and will produce the desired worm castings and worm tea. The apparatus is preferably provided with programmer so that it can be run according to preset protocols.
The above and other objects of the present invention will be more fully appreciated from the following description, claims and drawings in which:
In the drawings the following numbers describe the various elements of the apparatus and method:
An apparatus for receiving and decomposing organic materials employing worms and discharging a compost is provided comprising: a first outer conduit body 2, having a first diameter, a wall with exterior and interior surfaces defining a decomposition chamber, said body being fabricated from a section of corrugated metal pipe of the type having parallel helical corrugations extending around the exterior and interior wall surfaces of the pipe, said body having an inlet at one end and an outlet (opening) 32 at the opposite end; a second inner conduit 8, having a smaller diameter axially aligned and supported within the first conduit having an inside and outside wall defining a worm decomposition chamber, an inlet and outlet portion, the inside wall defining screw helical corrugations projections aligned so as to transport material introduced into the entrance and inside the conduit in the direction of the exit; a frame 1,5 having supporting means (support rollers 10, 31) for supporting said first and second conduits thereon wherein the angle of the common axis of the outer and inner conduits lies on a line slanted upwardly from horizontal from the inlet portion of said inner conduit:drive means (3, 4 and 9) including motor and drive means for rotating said conduits in a predetermined rotational direction and speed that facilitates the movement of the material in the second inner conduit toward the exit of said second conduit at a predetermined rotational speed; and baffles 34 extending axially along the internal wall of the second inner decomposition chamber near the inlet which baffles, 34, along with the interior screw helical corrugations, will mix the organic material and move the material between the inlet to the outlet as the body rotates at a predetermined speed and rotational direction as decomposition occurs.
The apparatus can also include in least one of said inlet and outlet is provided with openings for admission of air into the decomposition chamber. A heat exchange means can also be included extending into at least one of said decomposition chambers for circulating a heat exchange fluid through the said chamber to control the temperature within said chamber. The apparatus also preferably includes a means for adding moisture to the chambers. Optionally a grinder (shredder 6) is provided at a location prior to and connecting with the inlet of said inner second chamber such that organic wastes can be reduced in size before proceeding through the apparatus. The apparatus and process of the present invention will reduce waste being transported to landfills and provide an alternative solution to inorganic fertilizers. The new design can be automated thus requiring little manual labor and combine composting and separating processes into a dual stage design. The apparatus and process is designed to reduce household and industrial waste (such as from restaurants, large cafeterias, and shredded paper located on university campuses) currently allocated to landfills. According to the United States Environmental Protection Agency, 26% of the municipal solid waste stream can be composted and used as a rich organic fertilizer. There are several different systems that can be used for vermicomposting. However, until the invention and all encompassing system did not exist. The system disclosed herein comprises an all-in-one vermicomposting device in which composting and separating finished product occur simultaneously. When implemented this design will reduce the amount of waste being transported to landfills and provide an alternative solution to inorganic fertilizers.
The inner conduit can be affixed and aligned inside the outer conduit with the use of bolt/spacers mechanisms, welded braces or the like.
The problems of the prior art apparatus were identified and the invention is based on resolution thereof based on by several measurable objectives. The objectives define the function, size, cost, features, safety, and performance of the system. The system is designed to specifically meet the following objectives:
From the recognition of need and problem definition, the presently described invention was made.
The present invention comprises an all-in-one, automated system that can provide finished compost with the least amount of human interaction possible.
In one embodiment the apparatus of the present invention uses two rotating culvert conduits (one (inner) is centrally located and supported inside the other (outer) and both having a common axis) and both rotating in the same direction The organic waste material flows in two different directions (
The present invention removes serious complications found on known composters and is very cost effective to construct and use. Materials are easily obtainable in various sizes, allowing the design to be scaled up or down depending on a customer's requirement.
Due to its distinct simultaneous two-stage process allows added drying time for the finished compost and eliminates potential “dead spots” within units using agitators where areas can be missed. The slight angle allows ample time for vermicomposting and also for the drying period because of the rates of the corrugated tubing known as culverts. The flow is continuous from beginning to end.
Odor reduction over known composters is also an advantage of the invention.
Specifically, the slow rotating design and minimal pinch points add to the advantages of the invention. The scalability of the invention for large-scale implementation is also possible due to its widely available components in various sizes. Automation helps to remove error.
Certain criteria generated from the problem definition were generated and assigned a weight, based on a 9-3-1 scale. Criterions receiving a weight of 9 were considered highly important, a weight of 3 was considered moderately important, and a weight of 1 was considered least important. After weights were assigned to each criterion, each design concept was rated based on its level of adherence to the given criterion.
The following scale was used in the rating process.
The design concept with the highest overall score represents the better vermicomposting system. The criteria and weighting were; Compost(9) Rate(9), Safety(3), Size(3), Cost(3), Ease of Installation(3), Operation/Maintenance(3), Automated(3), Transportable (1) and Appearance(1). Based on the above the present invention was considered to be superior to other alternative designs.
In order to size and safely engineer the invention, standard engineering equations were implemented. To safely design each component, critical loads, torques, and deflections were considered in the engineering process. Realizing the main variable in the system is the weight of compost, design calculations were based on the culverts being loaded to maximum capacity.
Assuming a saturated compost density of 0.033 lb/in3 and weights of 42.2 lb and 73.6 lb for the 15 in diameter and 24 in diameter culverts respectively, a maximum total combined weight of 862.2 lb was determined. To achieve the greatest torque requirement, it was assumed that the culvert was half loaded and rotated 90° from natural resting position. Normal forces were calculated at each of the six rollers and used to determine the frictional force between the steel culvert and polyurethane roller. The coefficient of friction was found to be 0.2. The centroid of the compost was found to be 5.1 inch from the center of the culvert. Moments about the center of the culvert were summed to find the maximum force required to rotate the culvert (196.3 lb). This was then multiplied by the radius of the outer culver (1 ft) to calculate the minimum torque of the drive train. Using this torque and a predetermined rpm of two, power was calculated to size the electric motor. Due to a desired safety factor of three for this key component, a 0.25 hp electric motor was selected, It was calculated that 656.5 ft-lb of torque would be generated from this motor, far surpassing the minimum torque of 196.3 ft-lb determined earlier.
Since the free spin rpm of the motor is rated at 1725 rpm, a gear reduction system had to be implemented to achieve the desired culvert rotation (2 rpm). An in-line gear reducer with a ratio of 144:1 gives a final shaft output of 12 rpm. To achieve the desired 2 rpm, a 4 in diameter sprocket is used to create a 6:1 external gear ratio between culvert and motor.
Maximum load calculations were also used to determine deflection of load bearing frame members. Before calculations were done, the second moment of area of 11 gauge steel tubing was determined to be 0.0555 in4. The load of the culverts filled with compost creates a force on the supporting rollers that transfers the force to the lengthwise horizontal cross member pointed out below.
The force on the rollers is calculated to be 143.77 lb, which is used to determine maximum vertical force on the horizontal cross members. The max force on these cross members is found using summation of moments about multiple points on the roller support. Using this max force of 134.8 lb, the max deflection is found this Equation 1:
Y
MAX=(PL3)/(48E1) Equation 1
This gives a max deflection of 0.193 inch, which is acceptable in this unlikely case. This same equation is used on the end horizontal cross member sections. Forces on the ends of the lengthwise horizontal cross member are found to be 201.8 lb using summation of moments about an end point. Knowing this, it is possible to calculate the equivalent load acting on the middle of the cross member. This load was used in the deflection equation to determine a maximum deflection of 0.17 in on each of the end horizontal cross members.
With maximum load inside the culvert, summation of moments around two points found the unknown forces on the wheels. Understanding that the invention is symmetrically built this force was then divided by two because it will be distributed to two wheels through the axle.
Computational analysis using a computer aided in the calculation of stresses and deflections as well as the investigation of part and sub-assembly interactions while in motion. To determine how the drive sprocket would react to its non-typical use, the design team simulated the drive sprocket loaded under maximum operating conditions to determine the deflection and stresses within a tooth. As shown in the maximum stress level generated was 212.2 psi, which is well below the yield strength (1.36 psi) of the sprocket material (4150 steel). This confirms the sprocket will be capable of driving the culverts under maximum load conditions.
Another feature of this system is the end products generated from the composting cycle. Rich organic vermicompost and worm tea is produced as a finished usable product. These can be used by the homeowner and on an industrial scale can be sold to consumers.
To better understand the design modifications necessary to generate a functional system, an apparatus was constructed to test and verify the rotating culvert design. Experiments were conducted to establish the greatest angle that the compost would reliably climb the inner culvert. The apparatus used to test the rotating culvert design utilized a simple frame and caster wheels to support a 24″ outer culvert. A 15″ inner culvert was then inserted and centered within the outer culvert where it was secured with bracing. The two joined culverts were then set on the frame and loaded with compost. Wooden blocks were used to elevate the end of the frame opposite to the inlet of the inner culvert and adjust the angle. The culverts were then rotated manually to establish an optimized angle for the design. It was determined that a 7-degree incline was optimal and provided the best flow of compost through the culverts.
Overall dimensions of the apparatus of the example were Length 60″×Width 32″×Height 48″ allowing the system to easily pass through a standard doorway.
The apparatus was designed to run on common household utilities. A standard 110V electric hook up and ⅝″ garden hose can be used to run the system. The system will be completely assembled prior to delivery to end user.
A standard irrigation controller was used to automate irrigation and aeration of the system. This system will allow the operator to manually adjust irrigation and aeration durations to optimize composting conditions. The apparatus can be operated either with a program to provide automated control or the apparatus can be manually controlled.
The apparatus of the invention is an autonomous unit and will require the user to only input waste, empty the finished compost/worm tea, and periodically check the worm habitat. Before any worms or waste are placed into the unit, the following steps should be completed:
The following contains the recommended initial settings for the timing controller. The operation section outlines adjustments that may be necessary for various input levels.
Loading/Unloading
Irrigation and Aeration Schedule
Transporting the Apparatus
Clean Water Filter (6 Months)
Clean Worm Tea Filter (1 Month)
Clean Shredder (1 Month)
Clean Worm Tea Collection Tray (1 Month)
Clean Worm Tea Reservoir and Stone (2 Months)
Additional carbon or nitrogen may be added to the compost as desired with the preferred carbon-to-nitrogen ratio of about 30:1 by weight. Various nitrogen sources may be utilized such as nitrogen containing fertilizer, plants, vegetables, coffee grounds and the like. Carbon can be added in the form of paper, cardboard, leaves and the like. More red wiggler worms, bacteria, and fungus cultures may also be added to accelerate the process. It is also desirable to add water to the vermicompost materials to maintain moisture content of approximately 60% to 90%.
It will be obvious to those skilled in the art to make various changes, alterations and modifications to the vermicomposting method and apparatus described herein. To the extent such changes, alterations and modifications do not depart from the spirit and scope of the appended claims, they are intended to be encompassed therein.
Number | Date | Country | |
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61686132 | Mar 2012 | US |