Patent Publication Number: US-2021164209-A1

Title: Food waste disposal device

Description:
REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of International Patent Application PCT/KR2019/016676 filed on Nov. 29, 2019, which designates the United States and claims priority of Korean Patent Application No. KR 10-2019-0156440 filed on Nov. 29, 2019, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a food waste disposer, and more particularly, to a food waste disposer that is located on a sink drain to pulverize food waste generated by washing dishes and food and to thus separate solids and water from the pulverized food waste, thereby reducing the volume of the food waste, and that prevents bad smell and sewage from flowing backward from a drain pipe, thereby solving sanitation problems. 
     BACKGROUND OF THE INVENTION 
     A filter is located in a drain pipe of a sink in a kitchen of a general house or restaurant to prevent the drain pipe from being clogged with food waste generated by washing dishes and food. 
     In this case, food waste is accumulated in the filter to cause water drainage to become bad, and also, bad smell is generated from the accumulated food waste. 
     If the food waste is left for long hours, without any treatment, bad smell is generated therefrom, and further, worms and bacteria are cultivated to have a bad influence on the surrounding environments. 
     In the kitchens of general houses or restaurants, accordingly, the filter in which the food waste is accumulated is drawn from the drain pipe of the sink, and next, the food waste is put into a food waste bin and is thus thrown away. As the food waste contains a large amount of water, in this case, it is bulky and heavy, thereby accompanying a high cost of food waste disposal and insanitation problems. 
     So as to solve such problems, a conventional food waste treatment device is disclosed in Korean Patent No. 10-1847093 (entitled “food waste treatment device for sink”), which is hereinafter referred to as “conventional technology”. 
       FIG. 1  is an exploded perspective view showing a food waste treatment device for a sink according to a conventional technology. 
     The food waste treatment device  100  for a sink according to the conventional technology includes a hopper  110  located on a sink drain to collect pulverization objects thereto and to thus move them downward, fine pulverizing means  120  for pulverizing the pulverization objects introduced from the hopper  110  thereinto, and a forced discharging means  130  located on the underside of the fine pulverizing means  120  to discharge the pulverization objects pulverized to the outside. 
     The hopper  110  has a conical shape and is coupled to the sink drain to collect the pulverization objects thereto. 
     The fine pulverizing means  120  is located under the hopper  110  and includes a housing  121 , a pair of screws  122 , a net body  123 , and a housing cover  124 . 
     The housing  121  has the shape of a cylinder whose front surface is open and rear surface is closed, and further, the housing  121  has an opening  1211  formed on top thereof in such a manner as to be connected to the lower end periphery of the hopper  110 . 
     Furthermore, the housing  121  has a water outlet (not shown) formed on bottom thereof. 
     The water outlet is located on the rear side of the bottom of the housing  121  in such a manner as to discharge water of the pulverization objects pulverized by means of the screws  122  therethrough. 
     The screws  122  engage with each other horizontally inside the housing  121  and thus rotate, and if helical-shaped teeth formed on the outer peripheral surfaces of the screws  122  engage with each other to thus rotate the screws  122 , the pulverization objects introduced from the hopper  110  can be pulverized. 
     The net body  123  is located on the outside of the screws  122  and has a perforated surface formed on the underside thereof in such a manner as to allow the water of the pulverization objects pulverized by means of the screws  122  to be discharged through the water outlet. 
     The housing cover  124  has the shape of a cylinder whose front surface is closed and rear surface is open in such a manner as to be detachably mounted on the front side of the housing  121 . 
     Further, the housing cover  123  has a solid outlet  1241  formed on the underside thereof to discharge the solids of the pulverization objects pulverized by means of the screws  122  therethrough. 
     The forced discharging means  130  is located just on the underside of the housing  121  in such a manner as to communicate with the water outlet of the housing  121 . 
     The forced discharging means  130  has an impeller  131  located at the inside thereof to apply a forward propelling force in a forward direction by means of a rotating force received from a motor  132 . 
     The forced discharging means  130  forcedly discharges the water of the pulverization objects introduced from the water outlet to a drain pipe by means of the impeller  131 . 
     Under the above-mentioned configuration of the conventional technology, the pulverization objects introduced from the hopper  110  are separated into the water and the solids through the fine pulverizing means  120 , thereby reducing mass and volume of the food waste. 
     However, the food waste treatment device  100  according to the conventional technology does not have any separate backflow prevention function, so that sewage and bad smell flow backward from the drain pipe, thereby causing many inconveniences while the food waste treatment device  100  is being used. 
     Further, the food waste treatment device  100  according to the conventional technology does not have any separate cleaning means, and so as to prevent bad smell from coming up therefrom, accordingly, the housing cover  124  is periodically separated to directly clean the internal parts thereof, thereby making it inconvenient to use. 
     Furthermore, the food waste treatment device  100  according to the conventional technology causes the teeth of the screws  122  to be damaged if iron like spoons or chop sticks is introduced thereinto to collide against the screws  122 . 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a food waste disposer that is capable of allowing an opening and closing plate adapted to open and close a drain pipe to be open only when water is discharged to the drain pipe, so that in a state where the water discharge is finished, the drain pipe is closed by means of the opening and closing plate, thereby preventing bad smell and sewage from flowing backward from the drain pipe. 
     It is another object of the present invention to provide a food waste disposer that is capable of allowing an opening and closing plate to be closed, without opening a casing cover, if a motor is driven reversely, thereby cleaning internal parts thereof. 
     It is yet another object of the present invention to provide a food waste disposer that is capable of allowing a magnetic material to be built in a hopper into which pulverization objects and water are introduced, so that if iron introduced into the hopper is sensed by sensors, a pulverizing part stops working. 
     To accomplish the above-mentioned objects, according to the present invention, there is provided a food waste disposer adapted to pulverize pulverization objects introduced thereinto and thus to separatedly discharge the pulverization objects into solids and water, the food waste disposer including: a box-shaped casing having a solid outlet formed on one side thereof to discharge the solids therefrom and a water outlet formed on a lower portion thereof to discharge the water therefrom; a hopper located on top of the casing in such a manner as to introduce the pulverization objects into the casing; a pulverizing part located inside the casing to pulverize the pulverization objects introduced from the hopper; a water discharging part for discharging the water of the pulverization objects pulverized by means of the pulverizing part to the outside of the casing; and a driving part for transferring power to the pulverizing part and the water discharging part, wherein the pulverizing part includes: a plurality of pulverizing means located inside the casing to pulverize the pulverization objects and thus to move the solids of the pulverization objects pulverized in a forward direction; and a filter located on the outside of the pulverizing means and having water discharging holes adapted to discharge the water of the pulverization objects pulverized by means of the pulverizing means therethrough and at least one or more solid discharging holes adapted to discharge the solids of the pulverization objects pulverized by means of the pulverizing means therethrough, each pulverizing means including: a pulverizing shaft whose front end periphery is connected to the casing; a pulverizing gear located under the hopper in such a manner as to be fitted to the pulverizing shaft; and a compressing gear located in front of the pulverizing gear in such a manner as to be fitted to the pulverizing shaft to compress the pulverization objects pulverized by the pulverizing gear thereagainst, and the pulverizing means being spaced apart from each other in a transverse direction of the casing in such a manner as to allow the pulverizing gears to engage with each other. 
     According to the present invention, desirably, the filter includes: a filter cover comprising a pair of compressing gear insertion portions having the shapes of hollow cylinders whose front surface are closed to insert the front end peripheries of the compressing gears thereinto and an extended flange extended outward from the rear end peripheries of the compressing gear insertion portions to connect the compressing gear insertion portions to each other; a pair of front filters each having the shape of a pair of hollow semicircular cylinders connected to each other in a transverse direction and each provided with an insertion projection extended outward from the rear end periphery thereof so that as the front end peripheries thereof are inserted into the compressing gear insertion portions, the front filters are located above and under the compressing gears to thus surround the compressing gears; and a pair of rear filters each having the shape of a pair of hollow semicircular cylinders connected to each other in a transverse direction so that as the front end peripheries thereof are inserted into the insertion projections of the front filters, the rear filters are located above and under the pulverizing gears to thus surround the pulverizing gears, the front filters and the rear filters having a plurality of water discharging holes formed on the outer peripheral surfaces thereof, the upper side rear filter of the rear filters having a pulverization object introducing hole adapted to introduce the pulverization objects introduced from the hopper thereinto, and the filter cover having the solid discharging holes formed on the front surface thereof to discharge the solids of the pulverization objects therethrough. 
     According to the present invention, desirably, the casing includes: a pulverizing part casing adapted to locate the pulverizing part at the inside thereof in such a manner as to allow top thereof to communicate with the hopper; a casing cover located on the front side of the pulverizing part casing in such a manner as to allow the rear surface thereof to communicate with the pulverizing part casing to thus discharge the solids of the pulverization objects discharged through the solid discharging holes through the solid outlet; a water discharging part casing adapted to locate the water discharging part at the inside thereof in such a manner as to be connected to the underside of the pulverizing part casing; and a driving part casing adapted to locate the driving part at the inside thereof in such a manner as to be connected to the rear sides of the pulverizing part casing and the water discharging part casing. 
     According to the present invention, desirably, the casing cover has a flange insertion groove formed on the inner peripheral surface in such a manner as to insert the extended flange of the filter cover thereinto, and as the extended flange is inserted into the flange insertion groove, the filter cover isolates the casing cover from the pulverizing part casing to prevent the solids and water of the pulverization objects discharged from the filter from being mixed together. 
     According to the present invention, desirably, the water discharging part, which is located inside the water discharging part casing, includes: a propeller driving shaft rotating with a driving force received from the driving part; a propeller fitted to a front periphery of the propeller driving shaft; and an opening and closing plate located on an end portion of the water discharging part casing in such a manner as to open and close the end portion of the water discharging part casing, the opening and closing plate being open when the propeller rotates forward. 
     According to the present invention, the food waste disposer is configured to allow the opening and closing plate adapted to open and close the drain pipe to be open only when the motor operates, so that normally, the drain pipe from which water is discharged is closed, thereby preventing bad smell and sewage from flowing backward therefrom. 
     In addition, the food waste disposer according to the present invention is configured to allow the propeller adapted to forcedly discharge the water from the casing to the drain pipe to be driven reversely and to thus close the opening and closing plate if the motor is driven reversely, so that the gears inside the pulverizing part rotate to circulate the water in the casing and thus to automatically clean the casing, without any separation of the casing. 
     Further, the food waste disposer according to the present invention is configured to allow the magnetic material to be built in the hopper so that if iron introduced into the hopper is sensed by the sensors, the pulverizing part stops working and is thus prevented from being damaged by the iron. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view showing a food waste treatment device for a sink according to a conventional technology. 
         FIG. 2  is an exploded perspective view showing a food waste disposer according to the present invention. 
         FIG. 3  is a sectional view showing a casing of  FIG. 2 . 
         FIG. 4  is a perspective view showing a hopper of  FIG. 2 . 
         FIG. 5  is a perspective view showing a pulverizing part of  FIG. 2 . 
         FIG. 6  is an exploded perspective view showing the pulverizing part of  FIG. 5 . 
         FIG. 7  is a perspective view showing the underside of a filter cover of  FIG. 6 . 
         FIG. 8  is a sectional view showing a water discharging part of  FIG. 2 . 
         FIG. 9  is a sectional view showing a driving part of  FIG. 2 . 
         FIG. 10  is a sectional view showing an operating process of the food waste disposer according to the present invention. 
         FIG. 11  is a sectional view showing a process where a motor rotates reversely to clean an interior of the food waste disposer according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, the present invention will now be described in detail with reference to the attached drawings. 
       FIG. 2  is an exploded perspective view showing a food waste disposer according to the present invention. 
     As shown in  FIG. 2 , a food waste disposer  1  according to the present invention includes a casing  2 , a hopper  3  located on top of the casing  2  in such a manner as to be inserted into a drain  81  of a sink  8  to allow food waste (hereinafter, referred to as ‘pulverization objects’) to be transferred to the inside of the casing  2 , a pulverizing part  4  for pulverizing the pulverization objects introduced from the hopper  3  thereinto, a water discharging part  5  for discharging water in the casing  2  to a drain pipe  9  through a propeller  52 , and a driving part  6  for transferring power to the pulverizing part  4  and the water discharging part  5 . 
       FIG. 3  is a sectional view showing the casing of  FIG. 2 . 
     The casing  2  includes a pulverizing part casing  21  for locating the pulverizing part  4  at the inside thereof, a casing cover  22  located on the front side of the pulverizing part casing  21 , a water discharging part casing  23  provided on the underside of the pulverizing part casing  21  in such a manner as to locate the water discharging part  5  at the inside thereof, and a driving part casing  24  provided on the back side of the pulverizing part casing  21  in such a manner as to locate the driving part  5  at the inside thereof. 
     The pulverizing part casing  21  has the shape of a box open on the front and back surfaces thereof and is provided with an introducing portion  211  formed on top thereof in such a manner as to be coupled to the hopper  3  to introduce the pulverization objects thereinto. 
     Further, the pulverizing part casing  21  is provided with a water transferring portion  212  formed on underside thereof in such a manner as to transfer the water introduced from the hopper  2  to the water discharging part casing  23 . 
     Furthermore, the pulverizing part casing  21  is provided with protrusions  213  protruding from bottom thereof behind the water transferring portion  212 . 
     The protrusions  213  have the shapes corresponding to discharging holes  4351  formed on a second rear filter  435  of a filter  43  as will be discussed later, and when the discharging holes  4351  are coupled to the rear sides of the protrusions  213 , the protrusions  213  serve to close the discharging holes  4351  to prevent solids from being discharged through the discharging holes  4351 . 
     The casing cover  22  has the shape of a box closed on the front side thereof and open on the rear side thereof. 
     Further, the rear end portion of the casing cover  22  is coupled to the front end portion of the pulverizing part casing  21 . 
     In this case, the casing cover  22  includes hollow cylindrical shaft insertion portions  221  protruding backward from the front surface thereof in such a manner as to insert front end peripheries of pulverizing shafts  411  and  421  as will be discussed later thereinto and a hollow cylindrical solid outlet  222  formed on the underside thereof in such a manner as to discharge solids of the pulverization objects introduced into the pulverizing part  4  therethrough. 
     Further, the casing cover  22  includes a flange insertion groove  223  formed on the rear end thereof in such a manner as to insert an extended flange  4312  of a filter cover  431  as will be discussed later thereinto. 
     The water discharging part casing  23  has the shape of a box open on the front and rear surfaces thereof and is configured to allow top thereof to communicate with the water transferring portion  212  of the pulverizing part casing  21  to thus receive the water introduced into the pulverizing part casing  21 . 
     Further, the water discharging part casing  23  is provided with a water outlet formed on the front end thereof in such a manner as to be connected to the drain pipe  9  of  FIG. 2 , and accordingly, the water introduced into the water discharging part casing  23  is discharged to the drain pipe  9  through the water discharging part  5 . 
     Furthermore, the water discharging part casing  23  has a driving shaft fitting portion  231  formed on the rear end thereof in such a manner as to allow a propeller driving shaft  51  as will be discussed later to pass therethrough. 
     The driving part casing  24  has the shape of a box and is provided with a first through hole  241  and a second through hole  242  formed on the front surface thereof in such a manner as to pass the second pulverization shaft  421  and the propeller driving shaft  51  as will be discussed later therethrough. 
     Moreover, the driving part casing  24  locates the driving part  6  at the inside thereof. 
       FIG. 4  is a perspective view showing the hopper of  FIG. 2 . 
     As shown in  FIG. 4 , the hopper  3  has a conical shape and serves to collect the pulverization objects generated by cooking food or washing dishes. 
     Further, the hopper  3  has a flange  31  extended outward from the top end periphery thereof in such a manner as to be mounted on the drain  81  of the sink  8 . 
     Further, the lower end periphery of the hopper  3  is coupled to the introducing portion  211  of the pulverizing part casing  21 , and accordingly, the pulverization objects collected inside the hopper  3  are discharged to the pulverizing part casing  21  through the introducing portion  211 . 
     In this case, the hopper  3  has a plurality of connectors  32  formed on the side peripheral surface thereof. 
     The connectors  32  have cylindrical shapes and are provided with connector insertion holes  321  communicating with the inside of the hopper  3  in such a manner as to insert drain pipes of a dish washer and a water purifier thereinto. 
     For the convenience of the description, in this case, the connectors  32  are formed on the side periphery of the hopper  3 , but of course, they may be formed on the casing  2 , without being limited thereto. 
     Further, the hopper  3  is made of a plastic material and has a magnetic material built therein to prevent iron like spoons and chop sticks from being introduced into the casing  2 , thereby avoiding the pulverizing part  4  from being damaged. 
     Moreover, the hopper  3  is provided with sensors (not shown), and if the pulverization objects are introduced into the hopper  3 , the driving part  6  operates under the control of a controller (not shown) to allow the pulverization objects to be pulverized. Contrarily, if the iron is introduced into the hopper  3 , the driving part  6  stops working to prevent the pulverizing part  4  from being damaged by the iron. 
     In this case, various known sensors as the sensors are available, and a detailed explanation on the sensors will be avoided for the brevity of the description. 
       FIG. 5  is a perspective view showing the pulverizing part of  FIG. 2 , and  FIG. 6  is an exploded perspective view showing the pulverizing part of  FIG. 5 . 
     The pulverizing part  4  includes first and second pulverizing means  41  and  42  and the filter  43 . 
     The first pulverizing means  41  is comprised of the first pulverizing shaft  411 , a first pulverizing gear  412 , and a first compressing gear  413 . 
     The first pulverizing shaft  411  whose front end periphery is inserted into one of the shaft insertion portions  221  formed on the casing cover  22 . 
     The first pulverizing gear  412  is fitted to the first pulverizing shaft  411  in such a manner as to be located under the introducing portion  211  of the pulverizing part casing  21 . 
     The first compressing gear  413  is fitted to the first pulverizing shaft  411  in such a manner as to be located in front of the first pulverizing gear  412  to compress the pulverization objects pulverized by the first pulverizing gear  412  thereagainst, to discharge water through the compression, and to discharge solids of the pulverization objects to the solid discharging holes  43112  formed on the filter cover  431  of the filter  43  as will be discussed later. 
     The second pulverizing means  42  is spaced apart from the first pulverizing means  41  in a transverse direction and has a second pulverizing gear  422  and a second compressing gear  423  having the same shapes and structures as the first pulverizing gear  412  and the first compressing gear  413  of the first pulverizing means  41 . However, the second pulverizing means  42  has a second pulverizing shaft  421  having different shape and structure from the shape and structure of the first pulverizing shaft  411 . 
     The second pulverizing shaft  421  is longer than the first pulverizing shaft  411  of the first pulverizing means  41  and has a first driven gear  4211  fitted to a position close to the rear end periphery thereof. 
     The first driven gear  4211  engages with a driving gear  63  of the driving part  6  as will be discussed later and rotates with a driving force received from the driving part  6 , so that the second pulverizing shaft  421  to which the first driven gear  4211  is fitted rotates. 
     First, the first pulverizing means  41  and the second pulverizing means  42  are located to allow teeth of the first pulverizing gear  412  and the second pulverizing gear  422  to engage with each other, so that they rotate together to thus allow the pulverization objects introduced between the first pulverizing gear  412  and the second pulverizing gear  422  to be pulverized by means of the teeth of the first pulverizing gear  412  and the second pulverizing gear  422 . 
     If the first pulverizing means  41  and the second pulverizing means  42  receive the driving force of the driving part  6  through the first driven gear  4211 , the second pulverizing shaft  421  to which the first driven gear  4211  is fitted rotates, together with the first driven gear  4211 , and also, the first pulverizing shaft  411  connected to the second pulverizing shaft  421  through the first pulverizing gear  412  and the second pulverizing gear  422  rotates. 
     Further, the first pulverizing gear  412 , the second pulverizing gear  422 , the first compressing gear  413 , and the second compressing gear  423  are helical gears so that they move forward along their teeth when the pulverization objects are pulverized. 
     The filter  43  includes the filter cover  431 , a first front filter  432 , a second front filter  433 , a first rear filter  434 , and a second rear filter  435 . 
       FIG. 7  is a perspective view showing the underside of the filter cover of  FIG. 6 . 
     As shown in  FIG. 7 , the filter cover  431  includes compressing gear insertion portions  4311   a  and  4311   b  adapted to insert the front end peripheries of the first compressing gear  413  and the second compressing gear  423  thereinto and the extended flange  4312  extended outward from the rear end peripheries of the compressing gear insertion portions  4311   a  and  4311   b.    
     The compressing gear insertion portions  4311   a  and  4311   b  have the shapes of hollow cylinders whose front surface are closed, and they are spaced apart from each other in the transverse direction of the pulverizing part casing  21 . 
     Further, the compressing gear insertion portions  4311   a  and  4311   b  have pulverizing shaft through holes  43111  formed on the front surfaces thereof in such a manner as to pass the pulverizing shafts  411  and  421  therethrough and the solid discharging holes  43112  formed on the front surfaces thereof in such a manner as to discharge the solids of the pulverization objects pulverized by the first pulverizing means  41  and the second pulverizing means  42  therethrough. 
     In this case, the inner diameters of the compressing gear insertion portions  4311   a  and  4311   b  are larger than outer diameters of the first compressing gear  413  and the second compression gear  423  and outer diameters of the first front filter  432  and the second front filter  433 . 
     The extended flange  4312  is extended outward from the rear end peripheries of the compressing gear insertion portions  4311   a  and  4311   b  in such a manner as to connect the compressing gear insertion portions  4311   a  and  4311   b  to each other. 
     Further, the extended flange  4312  is inserted into the flange insertion groove  223  formed on the casing cover  22 , and as the casing cover  22  is separated from the pulverizing part casing  21 , the solids discharged from the solid discharging holes  43112  are prevented from being discharged to the water transferring portion  212 . 
     As shown in  FIG. 6 , the first front filter  432  has the shape of a pair of hollow semicircular cylinders connected to each other to insert the first compressing gear  413  and the second compressing gear  423  thereinto and is provided with a plurality of water discharging holes (not shown) penetrated into the inner peripheral surface thereof from the outer peripheral surface thereof. 
     Further, the inner diameters of the semicircular cylinders constituting the first front filter  432  are larger than the outer diameters of the first compressing gear  413  and the second compressing gear  423 , and the outer diameters thereof are smaller than the inner diameters of the compressing gear insertion portions  4311   a  and  4311   b  of the filter cover  431 . 
     Further, the first front filter  432  has a first rear filter insertion projection  4321  protruding from the rear end periphery thereof in such a manner as to insert a front end periphery of the first rear filter  434  thereinto. 
     The second front filter  433  has the same shape and structure as the first front filter  432  and is coupled facingly to the first front filter  432  around the first compressing gear  413  and the second compressing gear  423 . 
     The first front filter  432  and the second front filter  433  are coupled to each other in such a manner as to be located above and under the first compressing gear  413  and the second compressing gear  423  to surround the first compressing gear  413  and the second compressing gear  423 , while their front end peripheries being inserted into the compressing gear insertion portions  4311   a  and  4311   b  of the filter cover  431 . 
     The first rear filter  434  has the shape of a pair of hollow semicircular cylinders connected to each other to insert the first pulverizing gear  412  and the second pulverizing gear  422  thereinto and is provided with a plurality of water discharging holes (not shown) penetrated into the inner peripheral surface thereof from the outer peripheral surface thereof. 
     Further, the inner diameters of the semicircular cylinders constituting the first rear filter  434  are larger than the outer diameters of the first pulverizing gear  412  and the second pulverizing gear  422 , and the outer diameters thereof are smaller than the inner diameter of the rear filter insertion projection  4321  of the first front filter  432 . 
     In this case, the first rear filter  434  is located above the first pulverizing gear  412  and the second pulverizing gear  422  in such a manner as to allow the first pulverizing gear  412  and the second pulverizing gear  422  to be placed at hollow portions formed at the underside thereof. 
     Further, the first rear filter  434  has a pulverization object introducing hole  4341  formed on top thereof. 
     The pulverization object introducing hole  4341  is located under the introducing portion  211  of the pulverizing part casing  21  to allow the pulverization objects introduced from the introducing portion  211  to move toward the first pulverizing means  41  and the second pulverizing means  42 . 
     The second rear filter  435  has the shape of a pair of hollow semicircular cylinders connected to each other to insert the first pulverizing gear  412  and the second pulverizing gear  422  thereinto and is provided with a plurality of water discharging holes (not shown) penetrated into the inner peripheral surface thereof from the outer peripheral surface thereof. 
     Further, the inner diameters of the semicircular cylinders constituting the second rear filter  435  are larger than the outer diameters of the first pulverizing gear  412  and the second pulverizing gear  422 , and the outer diameters thereof are smaller than the inner diameter of the rear filter insertion projection  4331  of the second front filter  433 . 
     In this case, the second rear filter  435  is located under the first pulverizing gear  412  and the second pulverizing gear  422  in such a manner as to allow the first pulverizing gear  412  and the second pulverizing gear  422  to be placed at hollow portions formed at the top thereof. 
     Further, the second rear filter  435  has one pair of discharging holes  4351  formed on the rear end portions. 
     The second rear filter  435  is normally closed in such a manner as to allow the discharging holes  4351  formed on the rear side thereof to be closed by means of the protrusions  213  of the pulverizing part casing  21  to prevent the solids from being discharged, but if the discharging holes  4351  are located on the front side of the second rear filter  435 , they are open to discharge the solids to the water transferring portion  212 , together with the water. 
     Under the above-mentioned configuration of the pulverizing part  4 , if the pulverization objects are introduced into the pulverizing part  4  through the introducing portion  211 , they are pulverized by means of the first and second pulverizing gears  412  and  422  of the first and second pulverizing means  41  and  42  and are then compressed against the first and second compressing gears  413  and  423 , so that water is removed from them. 
     In this case, the water removed from the pulverization objects is discharged to the outside of the filter  43  through the water discharging holes formed on the first and second front filters  432  and  433  and the first and second rear filters  434  and  435 . 
     Further, the solids of the pulverization objects from which the water is removed are discharged through the solid discharging holes  43112  formed on the filter cover  411 . 
       FIG. 8  is a sectional view showing the water discharging part of  FIG. 2 . 
     As shown in  FIG. 8 , the water discharging part  5  is located inside the water discharging part casing  23  and includes the propeller driving shaft  51  rotating with the driving force received from the driving gear  63  of the driving part  6  as will be discussed later, the propeller  52  rotatingly fitted to the end periphery of the propeller driving shaft  51 , and an opening and closing plate  53  located on an end portion of the water discharging part casing  23  in such a manner as to open and close the end portion of the water discharging part casing  23 . 
     The propeller driving shaft  51  is inserted into the driving shaft fitting portion  231  of the water discharging part casing  23  and has a second driven gear  511  fitted to the rear end periphery thereof. 
     The second driven gear  511  engages with the driving gear  63  of the driving part  6  and thus rotates with the driving force received from the driving part  6 , so that the propeller driving shaft  51  coupled to the second driven gear  511  rotates. 
     The propeller  52  is fitted to the front end periphery of the propeller driving shaft  51 , and if it rotates forward, it applies a propelling force forward to discharge the water in the water discharging part casing  23  to the drain pipe  9 . 
     The opening and closing plate  53  has the shape of a disc and is located on the front end portion of the water discharging part casing  23 . 
     Further, the opening and closing plate  53  is made of an elastic material like rubber, and normally, it closes the front end portion of the water discharging part casing  23  by its self weight to prevent bad smell and sewage from flowing backward from the drain pipe  9 . 
     If the propelling force is applied to the opening and closing plate  53  from the propeller  52 , furthermore, the opening and closing plate  53  is open to allow the water in the water discharging part casing  23  to be discharged to the drain pipe  9 . 
     Under the above-mentioned configuration, normally, the water discharging part  5  closes the front end portion of the water discharging part casing  23  through the opening and closing plate  53  to prevent bad smell and sewage from flowing backward from the drain pipe  9 , and if the pulverization objects and water are introduced into the casing  2 , the water discharging part  5  applies the propelling force from the propeller  52  to the opening and closing plate  53  and thus to open the opening and closing plate  53 , so that the water in the water discharging part casing  23  is discharged to the drain pipe  9 . 
       FIG. 9  is a sectional view showing the driving part of  FIG. 2 . 
     The driving part  6  includes a motor  61  located inside the driving part casing  24 , a motor shaft  62  connected to the motor  61 , and the driving gear  63  fitted to the end periphery of the motor shaft  62 . 
     The driving gear  63  engages with the first driven gear  4211  and the second driven gear  511  to transfer the driving force of the motor  61  to the pulverizing part  4  and the water discharging part  5 . 
     For the convenience of the description, in this case, the driving gear  63  engages with the first driven gear  4211  and the second driven gear  511 , but of course, gears may be additionally located between the driving gear  63  and the first driven gear  4211  and the second driven gear  511 , respectively, according to installation space, gear ratio, and so on. 
       FIG. 10  is a sectional view showing an operating process of the food waste disposer according to the present invention. 
     If the food waste disposer  1  operates by a user or if introduction of the pulverization objects is sensed by means of the sensors (not shown) located on the hopper  3 , the motor  61  operates to rotate the driving gear  63  connected to the motor  61  through the motor shaft  62 , and further, the first driven gear  4211  and the second driven gear  511  engaging with the driving gear  63  rotate to operate the pulverizing part  4  and the water discharging part  5 . 
     If the pulverization objects are introduced into the pulverizing part casing  21  through the hopper  3 , they are pulverized by means of the first and second pulverizing gears  412  and  422  and are then compressed against the first and second compressing gears  413  and  423 , so that water is discharged from the compressed pulverization objects. 
     In this case, the solids of the pulverization objects are moved to the casing cover  22  through the solid discharging holes  43112  formed on the filter cover  411  and are then discharged to the outside through the solid outlet  222 . 
     Further, the water removed from the pulverization objects moves to the water discharging part casing  23  through the water discharging holes formed on the filter  43  and is then discharged to the drain pipe  9  because the opening and closing plate  53  is open by means of the propelling force of the propeller  52 . 
       FIG. 11  is a sectional view showing a process where the motor rotates reversely to clean an interior of the food waste disposer according to the present invention. 
     If the food waste disposer  1  rotates the motor  61  reversely to rotate the propeller  52  reversely, the propelling force of the propeller  52  is applied reversely to allow the opening and closing plate  53  to be closed. 
     In this state, if a cleaning solution or water is injected into the casing  2 , the solution or water is circulated inside the casing  2 , without being discharged through the drain pipe  9 . 
     As a result, the interior of the casing  2  can be simply cleaned, without being disassembled.