Abstract:
The present invention relates to a food waste treatment apparatus that can effectively dispose food waste containing a large amount of water, rapidly dry food waste using microwaves, and remove odors and vapors generating during the drying process, thereby discharging clean air. The food waste treatment apparatus comprises a pulverizer ( 10 ) for pulverizing food waste, an endless track ( 20 ) for transferring food waste, a plurality of containers ( 30 ) installed on the upper surface of the endless track ( 20 ) for storing pulverized food waste, and a microwave dryer installed above the endless track for drying the pulverized food waste by making microwaves pass through the endless track in a direction perpendicular to the moving direction of the endless track ( 20 ).

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. national phase application of international application PCT/KR2006/001085 filed Mar. 24, 2006 which designated the United States and claims priority of Korean Patent Applications No. 10-2005-0035684, filed on Apr. 28, 2005, and No. 10-2005-0100834, filed on Oct. 25, 2005, the entire contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a food waste treatment apparatus for disposing, drying, and recycling food waste as compost, and a nature-friendly food waste treatment apparatus for drying food waste using microwaves, capable of enhancing drying efficiency, and removing odor and vapors generated during the drying process using ozone and a variety of filters. 
     BACKGROUND OF THE INVENTION 
     Generally, food waste treatment is very difficult. That is, it is difficult to incinerate food waste or to bury the food waste in landfills because it contains a large amount of water. Further, standards for food waste treatment are becoming strict. 
     An example thereof is the regulation on food waste sorting and discharge. According to this regulation, food waste must be separated from other waste and discharged using a separate food waste bag. Even in this case, since the food waste contains a large amount of water, it easily decomposes in a food waste bag, thereby causing odor and polluting the surroundings with leachate. 
     In the ideal food waste discharge state, the food waste contains almost no moisture. However, it is difficult to completely dehydrate food waste using recent technologies. 
     Further, even though food waste contains many valuable contents worth recycling, the food waste is generally buried as it is because it is very difficult to treat and separate the valuable content from the food waste. That is, although the food waste can be used as feedstuff for animals or as compost after treatment that includes steps of pulverizing, drying, and mixing the food waste with other material, the food waste is generally discarded without being reused. 
     Accordingly, in order to reuse the food waste from houses and restaurants, the food waste must be discharged in a dehydrated state. 
     In consideration of the above problems, several kinds of food waste treatment apparatus have been developed. 
     One example of a conventional food waste dehydration apparatus is disclosed in Korean Patent Application No. 10-1997-0081044, and uses microwaves. The food waste dehydration apparatus includes a dry compartment having a space in which food waste can be stored, pulverized and dried, a rotating axis installed in the dry compartment, a mixing blade rotating along with the rotating axis, and a magnetron for heating food waste in the dry compartment. However, this apparatus has a disadvantage in that it takes a long time to dry food waste and it cannot dry food waste continuously. 
     A further dehydration apparatus entitled “a coating liquid drying apparatus using microwaves” is disclosed in a Korean patent application assigned Application No. 10-2000-0001881. 
       FIG. 1  is a perspective view and a sectional view illustrating the structure of the coating liquid drying apparatus using microwaves according to the conventional art. The apparatus is installed on a moving path of an object to be coated in coating equipment for continuously forming coating layers on the surface of an object, and comprises a box-type housing  3 , at least one magnetron  1  installed on the housing  3  for radiating microwaves into the housing  3 , a power supply unit  14  and a controller  15  for driving and controlling the operation of the magnetron  1  installed outside the housing  3 , a pull-in unit  17  and a pull-out unit  18  installed inside and outside an entrance of the housing  3  and having a microwaves shielding film  11  therein, and an air ventilation fan  12  and an air ventilation pipe for exhausting vapors and volatile solvents from coating liquid when drying the coating liquid. 
     The coating liquid drying apparatus according to the conventional art radiates microwaves on the coating liquid like a flashlight, so that there is a dead zone in which microwaves do not reach the object to be dried, and thereby it has low drying efficiency. Accordingly, it is difficult to dry food waste containing a large amount of water. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention has been devised in consideration of the aforementioned problems and situations, and it is an object of the present invention to provide a nature-friendly food waste treatment apparatus using microwaves, capable of continuously supplying pulverized food waste on an endless track, capable of eliminating odors, and having enhanced drying efficiency. 
     In order to achieve the above objects and advantages, according to one aspect of the present invention, there is provided a food waste treatment apparatus using microwaves, comprising a pulverizer for pulverizing food waste, a quantitative discharger for discharging the pulverized food waste at regular discharge rates using a pump, a plurality of containers installed on an endless track for storing and transferring the pulverized food waste discharged from the quantitative discharger, a microwave dryer installed above the container for drying the pulverized food waste in a manner such that microwaves are created by a magnetron and are reflected in a direction perpendicular to a horizontal direction which is a moving direction of the containers, and a post-treatment unit connected to a side of the microwave dryer for removing odors and vapors. 
     The microwave dryer may comprise a magnetron for creating microwaves, and a reflection means for reflecting the microwaves incident in a horizontal direction to direct the microwaves in a vertical downward direction, the reflection means having a fixed plate inclined at 45 degrees with respect to the horizon direction and rotated by being connected to a step motor. 
     The reflection means may comprise two reflection means having different sizes. 
     The reflection means may comprise two reflection means having different sizes whose ratio is 3:2. 
     The microwave dryer may have a tunnel-type housing, three reflection means installed in the housing, and three magnetrons corresponding to respective reflection means. 
     The housing may have respective shielding doors at an entrance side and an exit side thereof, thereby shielding the microwaves and preventing the microwaves from leakage. 
     The post-treatment unit may comprise an ozone generator, for supplying ozone to the odors and a variety of filters. 
     The food waste treatment apparatus may further comprise a rotating brush installed under the endless track for removing residue sticking to an inner surface of the container. 
     According to a further aspect of the present invention, there is provided a food waste treatment apparatus using microwaves, comprising a pulverizer for pulverizing food waste to a mash form and discharging in a downward direction, an endless track, installed under the pulverizer, moving in a continuous manner, and being made of material through which microwaves pass, for transferring pulverized food waste, a reflection plate installed in a space provided by the endless track, in a manner such that the reflection plate is distanced from the endless track, a microwave dryer installed above the endless track for radiating microwaves created by a magnetron in a downward direction, and a post-treatment unit connected to the microwave dryer for removing odors and vapors. 
     The food waste treatment apparatus may further comprise a rotating feeder disposed between the pulverizer and the endless track for supplying pulverized food waste on a surface of the endless track. 
     The reflection plate may have a plurality of bars arranged in a length direction and coupled to each other on a surface thereof. 
     The microwave dryer may comprise a chamber installed on a surface of the endless track and connected to the reflection plate, having an empty space therein, a plurality of magnetrons installed above the chamber, and a reflection inducing body installed in the chamber at an upper part of the chamber, and installed between the magnetrons in a length direction, the reflection inducing body having a structure in which a thickness thereof becomes smaller in a downward direction. 
     The endless track may be coated with silicon. 
     The pulverizer may comprise a cylindrical casing having an open upper end and an open lower end, a pulverizing plate coupled to the lower end of the cylindrical casing, and having a plurality of depressions arranged in a radial manner on a first portion of an upper surface thereof, and having a plurality of through holes at a second portion other than the first portion, and a pulverizing rotary unit coupled to the pulverizing plate and installed above the pulverizing plate, and having a plurality of pulverizing cutters, each protruding from an upper surface thereof and being defined by a plurality of divisional depressions. 
     The food waste treatment apparatus may further comprise a screen mesh disposed on an upper surface of the second portion of the pulverizing plate. 
     The pulverizing cutter may have a reverse trapezoid shape in which a front surface and respective side surfaces are inclined inward. 
     The food waste treatment apparatus according to the present invention has the following advantages. 
     First, it has enhanced drying efficiency because microwaves is irradiated on food waste in a direction perpendicular to the food waste, and can reduce costs by decreasing a cycle time. 
     Second, it is a nature friendly apparatus and maintains a comfortable indoor environment by eliminating odors when it dries food waste. 
     Third, it can pulverize food waste into a mashed form, and enhance drying efficiency by reflecting microwaves two times in a chamber using a reflection-inducing body and a reflection plate, so that the microwaves head in an upward direction and then a downward direction in the chamber. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The advantages and features of the present invention may be understood more readily with reference to the accompanying drawings, but the present invention should not be construed as being limited to the accompanying drawings. Further, simple modification and replacement of elements of the present invention may be considered as being included in the scope of the present invention. 
         FIG. 1  is a perspective view and a sectional view illustrating a coating liquid drying apparatus using microwaves according to the conventional art; 
         FIG. 2  is a schematic front view illustrating a food waste treatment apparatus according to one embodiment of the present invention; 
         FIG. 3  is a schematic diagram illustrating the combination of a microwave dryer and a post-treatment unit of the food waste treatment apparatus according to the present invention; 
         FIG. 4  is a perspective view illustrating the food waste treatment apparatus according to the present invention, in which the microwaves drying unit and the post-treatment unit are integrated into a single body; 
         FIG. 5  is a schematic view illustrating the detailed inner structure of the microwaves drying unit; 
         FIG. 6  is a plan view illustrating a reflection means; 
         FIG. 7  is a schematic view illustrating a food waste treatment apparatus according to a further embodiment of the present invention; and 
         FIG. 8  is an exploded perspective view illustrating the food waste treatment apparatus shown in  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, a food waste treatment apparatus using microwaves according to the present invention will be described with reference to the accompanying drawings. 
       FIG. 2  is a front view and  FIG. 3  is a schematic diagram illustrating the food waste treatment apparatus according to one embodiment of the present invention. 
     Referring to  FIG. 2  and  FIG. 3 , the food waste treatment apparatus comprises a pulverizer  10 , a quantitative discharger  20 , a microwave dryer  40 , and a post-treatment unit  50 . Food waste is introduced into the pulverizer  10  through an upper part thereof, and is pulverized therein by rotating cutters, so that the food waste is changed into a mashed form. 
     The mashed food waste is forcedly transferred to the quantitative discharger  20  by a pump, and is discharged at a predetermined rate through a nozzle  25 . The pulverizer  10  and the quantitative discharger  20  are selected from the conventional ones, so a description of their details will be omitted. 
     Referring to  FIG. 2 , an endless track  30   a  is installed, and a plurality of the containers  30  is arranged in a row on the endless track  30   a . The containers  30  continuously move along with the endless track  30   a , and receive and store the mashed food waste discharged from the nozzle  25  of the quantitative discharger  20 . 
     The discharging of the mashed food waste is intermittently performed through the nozzle  25 . That is, when one container is disposed under the center of the nozzle, the food waste is discharged into the container from the discharger, and the discharging of the food waste is intercepted while the containers move. The discharging of the food waste can be controlled according to the moving speed of the endless track so that the food waste can be introduced into the containers. 
     The microwave dryer  40  is installed above the container  30  in a manner such that microwaves reach the surface of the food waste in the container  30  moving in a horizontal direction, in a direction perpendicular to the surface of the food waste, thereby enhancing drying efficiency. If it is needed, a plurality of microwave dryers can be installed in order to more highly enhance the drying efficiency. 
       FIG. 4  illustrates the microwave dryer and  FIG. 5  illustrate the inside structure of the microwave dryer. 
     The microwave dryer  40  includes a magnetron  41  for creating microwaves. The magnetron  41  is a conventional one, so a detailed description thereof will be omitted. 
     The microwave dryer  40  further includes a reflection means  42  disposed near the magnetron  41 . The reflection means  42  is connected to a step motor  43  and is rotated by the step motor  43 . The reflection means  42  has a plate  42 - 2  that is fixed to an edge of an arm  42 - 1  and inclined inward at 45 degrees from a horizontal direction, so that microwaves created by the magnetron  41  and incident onto the plate  42 - 2  in a horizontal direction are reflected from the plate  42 - 2  and then head in a vertical direction after being reflected. 
       FIG. 6  is a plan view illustrating the reflection means. Referring to  FIG. 6 , the reflection means includes three arms  42 - 1 , each arranged at an angle of 120 degrees. The plates  42 - 2  are connected to the respective ends of the arms  42 - 1 . 
     Referring to  FIG. 5 , the microwave dryer  40  comprises a plurality of pieces of the reflection means  42  connected in series in a vertical direction. According to this embodiment of the present invention, two reflection means  42  having different sizes are installed and are connected to the step motor  43 . The ratio of sizes of the two reflection means  42  is preferably 3:2. According to need, three or more reflection means  42  can be included. 
     Referring to  FIG. 4 , the microwaves drying unit  40  has a housing  40   a  having a long tunnel shape, and has three magnetrons  41 . In this case, three reflection means  42 , corresponding to the three magnetrons  41 , are installed in the housing  40   a.    
     The post-treatment unit  50  purifies air by absorbing odors and vapors generated during the drying process performed by the microwave dryer  40 . 
     For post-treatment, a suction duct  51  is connected to the microwave dryer  40 , and a suction blower  52  and a mixer  53  are installed. The suction blower  52  sucks odors and mixes the collected odors with ozone. For ozone mixing, an ozone generator  54  is included. As the odors mix with ozone from the ozone generator  54 , the odors are preliminary purified. 
     The odors purified by the mixer  53  and vapors are transferred to a variety of filters  55 . Examples of the filters  55  include a carbon filter, a zeolite filter, and a P.P. filter. The numbers and types of the filters vary according to need. The post-treatment unit  50  preferably further includes a condensation means  56  for condensing vapors, thereby separating the vapors from air. 
     The odor is further purified by the filters  55  and the condensation means  56 , so that finally emitted air does not contain hazardous components. 
     In the case of the tunnel-shape microwave dryer, as shown in  FIG. 4 , three suction ducts  51  are connected to the housing  40   a  to eliminate odors. 
     As shown in  FIG. 2 , the food waste treatment apparatus according to the present invention, preferably includes one or more rotating brushes  60  under the endless track  30   a . The mashed content in the container  30  is dehydrated by the microwave dryer  40  and moves along the endless track  30   a , so that the dehydrated food waste is transferred to a separate food waste collection container. Respective empty containers continuously move along the endless track  30   a  for continuous drying, and are filled with mashed food waste when they are located under the nozzle. 
     When emptying the containers, there can be residue attached in the bottoms of the containers. Accordingly, the rotating brush  60  is provided to remove the residue from the containers after emptying the containers. The rotating brush removes the residue by brushing the bottom of the container. 
     The operational principles of the food waste treatment apparatus according to the present invention will be described below. 
     Food waste is introduced into the pulverizer and is then pulverized in the pulverizer. The pulverized food waste is discharged to the containers disposed under the nozzle using the quantitative discharger and the pump. That is, the containers installed on the endless track are then sequentially filled with the pulverized food waste and move along the endless track, thereby sequentially entering into the microwave dryer. The food waste in the containers is dried rapidly in the microwave dryer. Since a plurality of reflection means is arranged in series, it is possible to enhance the drying efficiency and is possible to continuously dehydrate food waste using containers moving along the endless track. 
     After the food waste passes out of the microwave dryer, the dehydrated food waste is collected in the separate food waste collection container, and the food waste can be continuously dried as the containers move and enter the microwave dryer continuously. 
     The odors and vapors generated during the drying process using the microwave dryer are purified by the post-treatment unit and then are discharged into the air. 
     Referring to  FIG. 7 , a food waste treatment apparatus according to a further embodiment of the present invention will be described.  FIG. 7  is a plan view illustrating the food waste treatment apparatus according to this embodiment of the present invention, and  FIG. 8  is an exploded perspective view illustrating the pulverizer of this apparatus. 
     The food waste treatment apparatus according to the further embodiment of the present invention includes a pulverizer  100 , an endless track  200 , a reflection plate  300 , a microwave dryer  400  and a post-treatment unit (not shown). The pulverizer  100  pulverizes the food waste into a mashed form, and discharges the mashed food waste. 
     The pulverizer  100  includes a cylindrical casing  110  having an open upper end and an open lower end, and a pulverizing plate  120  coupled to the lower end of the cylindrical casing  110 . The pulverizing plate  120  has a disk shape, and has depressions  125  formed on an upper surface thereof in a first zone thereof, and has a plurality of through holes  127  in a second zone other than the first zone where the depressions  125  are formed. 
     As shown in the drawings, the area of the second zone in which the through holes  127  are formed is about a quarter of the entire area of the pulverizing plate  120 , and the depressions  125  are formed in the second zone, which occupies three quarters of the entire area of the pulverizing plate  120 . 
     The depressions  125  can be preferably also formed in the second zone between the through holes  127 . 
     More preferably, a screen mesh  129  can be installed on the pulverizing plate  120  in the first zone where the through holes  127  are formed, so that insufficiently pulverized food waste is prevented from being discharged through the through holes  127 . 
     Further, a pulverizing rotary unit  130  is disposed on the surface of the pulverizing plate  120  and a shaft is installed in the center of the pulverizing rotary unit  130  connected to a motor. 
     The outermost diameter of the pulverizing rotary unit  130  is the same as a diameter of an imaginary circle formed by an imaginary line connecting the depressions  125 . A plurality of divided depressions  135  arranged at regular intervals forms protruding pulverizing cutters  137 . In this embodiment, there are six cutters. 
     The pulverizing rotary unit  130  is combined with the pulverizing plate  120  and is distanced from the surface of the pulverizing plate  120 , and pulverizes food waste by rotating the pulverizing plate  120 . 
     The front surface and respective side surfaces of the pulverizing cutter  137  incline inward, so that the pulverizing cutter  137  has a reverse trapezoid shape. Since the front end and respective sides of the pulverizing cutter  137  are inclined, food waste can more easily pass between the cutters  137 , so that the food waste can be more thoroughly pulverized. 
     The food waste pulverized by the pulverizer  100  is discharged through the through holes  127 , and a food waste feeder  150  is installed under the through holes  127 . The feeder  150  is a rotating body having a plurality of depressions formed at regular intervals. The food waste is introduced into the depressions, and is then rotated by the rotating body. The food waste falls down, and is finally scattered on the surface of the endless track. 
     The endless track  200  engages with a pulley P so that it can move endlessly. 
     The endless track  200  is made of material through which microwaves can penetrate and which can endure a high temperature of about 800 to 900° C. For example, the endless track  200  is made of a fabric woven with silicon dioxide fiber, or with glass fiber. 
     The endless track  200  may be coated with a silicon layer on the surface thereof. Thanks to the silicon layer, the dried food waste is more easily pulverized. 
     The reflection plate  300  is installed in a space provided by the endless track  200  in a manner such that it is separated from the endless track  200  and is not in contact with the endless track  200 . The reflection plate  300  may be a metal plate. The distance between the surface of the reflection plate and the endless track can be adjusted according to need. 
     A plurality of bars b is arranged on the surface of the reflection plate  300  at regular intervals in a length direction, in a manner such that the bars b are not in contact with the inner surface of the endless track and cannot be loosened in the vertical direction. 
     The microwaves drying unit  400  is installed above the endless track  200  and includes a magnetron that creates microwaves and radiate the microwaves in the vertical direction. 
     The microwaves drying unit  400  includes a chamber  410 , a magnetron  420 , and a reflection-inducing body  430 . The chamber  410  is installed above the endless track  200 , is connected to the reflection plate  300 , and has an empty space therein. 
     The magnetron  420  is installed above the chamber  410 , generates microwaves and radiates them into the chamber  410 . The plurality of reflection-inducing bodies  430  is installed in the chamber  410  at an upper part thereof between the plurality of magnetrons  420 . 
     Each of the reflection-inducing bodies  430  has a shape in which the thickness thereof decreases from an upper part to a lower part. According to this embodiment, the reflection-inducing body  430  is formed in a stepwise shape, and has a sharp lower end. Thanks to the above-described structure of the reflection inducing body, the total surface area of the reflection-inducing body increases, thereby enhancing the microwave reflection efficiency. 
     Thanks to variation of thickness of the reflection-inducing body, a dead zone, which microwaves do not reach, does not exist. 
     The microwaves created by the magnetron  420  are reflected from the reflection-inducing bodies  430 , head in the downward direction, pass through the endless track  200 , are reflected again from the surface of the reflection plate  300 , and head in an upward direction, thereby drying the food waste on the endless track with high drying efficiency. 
     The odors and vapors produced from the pulverized food waste and dried by the microwaves are removed by the post-treatment unit (not shown). The post-treatment unit in the apparatus according to this embodiment is the same as that in the apparatus according to the previously described embodiment. The odors and vapors are collected through a duct connected to the chamber, and a detailed description thereof will be omitted. 
     INDUSTRIAL APPLICABILITY 
     The food waste treatment apparatus according to the present invention has high drying efficiency, thereby being capable of being used widely in houses and restaurants. The food waste treatment apparatus according to the present invention can be used as a sludge dehydration apparatus.