Patent Publication Number: US-11021832-B2

Title: Detergent box and laundry treating apparatus including same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage application under 35 U.S.C. § 371 of International Application No. PCT/KR2017/012655, filed on Nov. 9, 2017, which claims the benefit of Korean Application No. 10-2016-0149418, filed on Nov. 10, 2016. The disclosures of the prior applications are incorporated by reference in their entirety. 
     TECHNICAL FIELD 
     The present invention relates to a detergent box and a control method of a clothing processing apparatus including the same. 
     BACKGROUND ART 
     In general, the term “clothing processing apparatus” refers to an apparatus capable of performing washing and drying or either washing or drying of clothes and the like. Here, the clothing processing apparatus may perform only the washing or drying function, or both the washing function and the drying function. Recently, washing machines provided with a steam supply device to perform a refresh function, such as removing wrinkles, odors, static electricity, and the like from clothes have been spreading. 
     Conventional clothing processing apparatuses are divided into a front loading type and a top loading type according to a clothing retrieval direction. Also, clothing processing apparatuses are divided into a vertical type apparatus in which a pulsator or a washing tub is rotated, and a horizontal type in which a drum is rotated, by the manner of washing. 
     A typical example of the horizontal type is a drum washing machine or a drum dryer. 
     The size of such clothing processing apparatuses is gradually increasing in recent years to meet user demand. That is, the size of the washing machines for domestic use is gradually increasing. 
     Generally, each household is equipped with one high-capacity clothing processing apparatus. Accordingly, when the laundry is to be washed by classifying the clothes according to the types of the clothes, the clothing processing apparatus is used many times. For example, when where laundry such as adult clothes and laundry such as underwear or baby clothes need to be separately washed, the clothing processing apparatus will be used for washing of the latter laundry after washing of the former laundry is completed. 
     As a result, a long time and large energy consumption are required to perform the washing operation. 
     Further, it is not preferable in terms of energy saving to use a conventional large-size clothing processing apparatus in washing a small amount of clothing. The washing phase provided in most large-size clothing processing apparatuses presumes a large amount of laundry, and thus consumes a large amount of water. In addition, as a large-size drum or inner tub needs to be rotated, large power consumption takes place. 
     In addition, since the washing phase presumes a large amount of laundry, the washing time is relatively long. 
     In addition, since the large-size clothing processing apparatus is provided with the washing phase considering typical clothes, it may not be suitable for washing of delicate fabrics such as underwear or baby clothes. 
     Further, the large-size clothing processing apparatus is not suitable for a case where a small amount of laundry needs to be frequently washed. Consumers collect laundry for a few days or a longer period to wash the laundry at a time. 
     It is not good in terms of cleanliness to leave underwear and baby clothes unwashed for a long time. When the laundry is left for a long time, stains are stuck to the fabrics and thus the laundry is not thoroughly washed. 
     Accordingly, there is a need for a small clothing processing apparatus which has a much smaller capacity than the conventional large clothing processing apparatus. 
     However, even when small-size clothing processing apparatuses are used, it is not preferable in terms of space utilization and aesthetics to install two clothing processing apparatuses side by side in the same house. 
     In recent years, a drawer-type clothing processing apparatus has been introduced to address the above-described issues. 
     The conventional drawer-type clothing processing apparatus is provided with a drawer to be drawn in and out of a cabinet having an opening at the front thereof. 
     The drawer-type clothing processing apparatus may be used alone or in combination with another clothing processing apparatus arranged at the top or bottom thereof to wash a small amount of laundry and enhance space utilization. 
     The drawer-type clothing processing apparatus generally includes a tub configured to accommodate wash water in a drawer, and a drum rotatably arranged in the tub. 
     Since the drawer is arranged to be drawn out of the cabinet, a water supply unit configured to supply water to the tub and a drainage unit configured to drain water from the tub are generally provided at the rear of the drawer. Here, the term “rear” refers to a side to which the drawer is inserted into the cabinet. 
     Here, the drawer may be provided with a detergent box. In general, the detergent box of the conventional drawer-type clothing processing apparatus should be connected to a detergent watering pipe for supplying water, and also a detergent discharge pipe for discharging the detergent from the detergent box to the tub is separately provided. 
     In the case where the detergent box provided to the drawer is arranged on the rear side of the drawer, the user can reach the detergent box and introduce a detergent and a fabric softener into the detergent box only when the drawer is drawn out until a portion provided with the detergent box is exposed, which causes a great inconvenience to the user. 
     In the case where the detergent box is provided in front of the drawer, it is easy for the user to reach the detergent box. However, the detergent watering pipe and the detergent discharge pipe connected to the detergent box needs to be elongated. Thereby, the space where the detergent watering pipe and the detergent discharge pipe can be installed may be narrowed, or the introduction port of the drum and the tub may be partially blocked due to the detergent watering pipe and the detergent discharge pipe. 
     Further, in the case where a separate detergent watering pipe or detergent discharge pipe is provided to the detergent box, a separate valve for controlling the flow rates in the detergent watering pipe and the detergent discharge pipe, or a separate control means for opening and closing the valve needs to be provided, which causes inconvenience. 
     DISCLOSURE 
     Technical Problem 
     An object of the present invention devised to solve the problem lies on a laundry treating apparatus having a detergent box which is capable of incorporating a water supply pipe for supplying water to the detergent box and a drain pipe into one pipe. 
     Another object of the present invention is to provide a laundry treating apparatus having a detergent box which is capable of supplying water from a tub to the detergent box. 
     Another object of the present invention is to provide a laundry treating apparatus which uses rotation of a drum in supplying water to a detergent box and discharging a detergent. 
     Another object of the present invention is to provide a control method of a laundry treating apparatus capable of automatically introducing a detergent or a fabric softener to a tub by controlling revolutions per minute of a drum. 
     Technical Solution 
     The objects of the present invention can be achieved by providing a detergent box including a body portion providing a space for storing a detergent and having an opening at a top thereof, a housing allowing the body portion to be detachably accommodated therein, a housing through hole formed through a lower portion of the housing to allow water to be introduced or water and the detergent to be discharged together, a discharge pipe protruding from a lower portion of the body portion toward the opening and having a hollow for discharging the detergent, and a discharge pipe cover configured to guide the water and the detergent into the hollow when a reference amount or a larger amount of water flows into the body, a part of the discharge pipe being inserted into the discharge pipe cover, the detergent box further including a block unit communicating with the discharge pipe and having a predetermined space between a lower portion of the body portion and a bottom surface of the housing to prevent water introduced into the housing from contacting the discharge pipe. 
     In order to achieve the objects of the present invention, the block unit may include a block body accommodated in the housing, at least a part of the body portion being accommodated in the block body, and a block through hole formed in a bottom surface of the block body such that the detergent discharged from the discharge pipe is discharged into the housing. 
     In order to achieve the objects of the present invention, the block unit may further include a block check valve arranged outside the bottom surface of the block body to shield the block through hole. 
     In order to achieve the objects of the present invention, the block check valve may be a buoyancy type check valve having a specific gravity less than a specific gravity of water. 
     In order to achieve the objects of the present invention, the block check valve may be made of a rubber material. 
     In order to achieve the objects of the present invention, the block unit may include a block barrel extending from a lower end of the body portion having the discharge pipe, wherein the block barrel may include a communication hole provided at one end to communicate with the discharge pipe and a block through hole provided at an opposite end to communicate with the housing. 
     In order to achieve the objects of the present invention, the block unit may further include a block check valve arranged outside a bottom surface of the block body to shield the block through hole. 
     In order to achieve the objects of the present invention, when the body portion is accommodated in the housing, an outer circumferential surface of the body portion and a side surface of the housing may be spaced apart from each other by a predetermined distance, and the side surface of the housing may be arranged at a higher position than the opening such that water introduced into the housing flows into the body portion through the opening along the outer circumferential surface of the body. 
     The objects of the present invention can be achieved by providing a laundry treating apparatus including a tub providing a space for storing water, a drum rotatably arranged in the tub to provide a space for storing clothes, a detergent box arranged outside the tub to provide a space for storing a detergent and configured to be supplied with water only from the tub, a tub through hole formed through an inner circumferential surface of the tub, and a connection portion communicating with the tub through hole on one side thereof and with the detergent box on an opposite side thereof, such that at least a part of the water moving along an inner circumferential surface of the tub due to centrifugal force generated when the drum rotates is introduced into the detergent box, mixed with the detergent, and then discharged back to the inner circumferential surface of the tub 
     The detergent box includes a body portion providing a space for storing a detergent and having an opening at a top thereof, a housing allowing the body portion to be detachably accommodated therein, a housing through hole formed through a lower portion of the housing to communicate with the connection portion, and a discharge pipe cover configured to guide the water and the detergent into the hollow when a reference amount of water or a larger amount of water flows into the body, a part of the discharge pipe being inserted into the discharge pipe cover, the detergent box further including a block unit communicating with the discharge pipe and having a predetermined space between a lower portion of the body and a bottom surface of the housing to prevent water introduced into the housing from contacting the discharge pipe. 
     In order to achieve the objects of the present invention, the block unit may include a block body accommodated in the housing, at least a part of the body portion being accommodated in the block body, and a block through hole formed in a bottom surface of the block body such that the detergent discharged from the discharge pipe is discharged into the housing. 
     In order to achieve the objects of the present invention, the block unit may further include a block check valve arranged outside the bottom surface of the block body to shield the block through hole. 
     In order to achieve the objects of the present invention, the block check valve may be a buoyancy type check valve having a specific gravity less than a specific gravity of water. 
     In order to achieve the objects of the present invention, when the body portion is accommodated in the housing, an outer circumferential surface of the body portion and a side surface of the housing may be spaced apart from each other by a predetermined distance, and the side surface of the housing may be arranged at a higher position than the opening such that water introduced into the housing flows into the body portion through the opening along the outer circumferential surface of the body. 
     In order to achieve the objects of the present invention, the detergent box may be arranged at a position higher than a maximum water level of water that can be accommodated in the tub when the drum is stopped. 
     In order to achieve the objects of the present invention, when an amount of water introduced into the detergent box through the connection portion is greater than or equal to a reference amount, the detergent box may discharge the detergent and water from the detergent box back to the connection pipe using a siphon effect. 
     In order to achieve the objects of the present invention, the water in the tub may be discharged to the connection portion and introduced into the detergent box by the centrifugal force only when the drum rotates at a speed higher than or equal to a first revolutions per minute (RPM). 
     In order to achieve the objects of the present invention, the tub through hole may be provided at a water level reached by the water in the tub when the drum rotates at the first RPM. 
     In order to achieve the objects of the present invention, the inner circumferential surface of the tub may be provided with first resistive ribs protruding from both sides of a surface having the through hole to generate resistance against water rotating on the inner circumferential surface of the tub such that the water flows into the through hole only when the drum rotates at a speed higher than or equal to a reference revolutions per minute (RPM). 
     In order to achieve the objects of the present invention, the inner surface of the tub may be provided with a second resistive rib arranged under the through hole to protrude toward a bottom surface of the tub. 
     In order to achieve the objects of the present invention, the block unit may include a block barrel extending from a lower end of the body portion having the discharge pipe, wherein the block barrel may include a communication hole provided at one end to communicate with the discharge pipe and a block through hole provided at an opposite end to communicate with the housing. 
     In order to achieve the objects of the present invention, the block unit may further include a block check valve arranged outside a bottom surface of the block body to shield the block through hole. 
     In order to achieve the objects of the present invention, the drawer may further include a drawer body for accommodating the tub and the drum, and a drawer panel arranged on the drawer body to open and close the opening, wherein the detergent box may be provided to the drawer panel. 
     Advantageous Effects 
     In a laundry treating apparatus having a detergent box according to the present invention, a water supply pipe for supplying water to the detergent box and a drain pipe may be integrated into one pipe, thereby improving space utilization. 
     In the laundry treating apparatus having a detergent box according to the present invention, water in the tub is supplied to the detergent box, and thus a detergent watering pipe connected to a water supply unit to supply water to the detergent box may be omitted. 
     In the laundry treating apparatus having a detergent box according to the present invention, a detergent contained in the detergent box may be discharged to a single pipe through which water is supplied from a tub. 
     In the laundry treating apparatus according to the present invention, only rotation of the drum may be used to supply water to the detergent box and discharge the detergent, and thus a separate control means or a flow rate control means may be omitted. 
     The present invention may provide a control method for a laundry treating apparatus capable of automatically introducing a detergent or a fabric softener into a tub by controlling revolutions per minute of a drum. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIGS. 1 and 2  show a basic structure of a laundry treating apparatus according to the present invention. 
         FIG. 3  shows a structure in which a detergent box is connected to a tub. 
         FIG. 4  shows a structure in which the detergent box generates a siphon effect according to revolutions per minute of a drum. 
         FIG. 5  shows a position where the detergent box is installed. 
         FIG. 6  shows a cross-sectional view of a tub that blocks water from flowing into the detergent box due to vibration and temporary high-speed rotation of the drum. 
         FIG. 7  is a perspective view of the tub that blocks water from flowing into the detergent box due to vibration and temporary high-speed rotation of the drum. 
         FIG. 8  shows another embodiment of a detergent box in which a siphon effect is not interrupted. 
         FIG. 9  shows a flow direction of water supplied to the detergent box to maintain a siphon effect. 
         FIG. 10  illustrates another embodiment of a detergent box in which a siphon effect can be maintained. 
         FIG. 11  illustrates a control method capable of supplying a detergent and a fabric softener to the laundry treating apparatus of the present invention. 
     
    
    
     BEST MODE 
     Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The configuration and control method of a device described below are only for explaining embodiments of the present invention and are not intended to limit the scope of the present invention. The same reference numerals will be used throughout the specification to refer to the same or like parts. 
     As shown in  FIGS. 1 and 2 , the laundry treating apparatus  100  of the present invention may include a cabinet  2 , a drawer  3  arranged to be withdrawable from the cabinet, a tub  4  arranged in the drawer to store water, and a drum  5  rotatably arranged in the tub to store clothes. 
     The laundry treating apparatus of the present invention shown in the figures is merely intended to illustrate the structure of the drawer-type washing machine and is not limited to the above-described configuration. 
     The laundry treating apparatus of the present invention may be provided in any structure as long as the drawer  3  can be drawn out of the cabinet  2 , and may have any internal structure. 
     The cabinet  2  may be provided as a means for defining an outer appearance of the laundry treating apparatus, or may be provided simply as a space for accommodating the drawer  3 . In any case, the front of the cabinet  2  may be provided with an opening  21  into which the drawer  3  is inserted. 
     The drawer  3  may include a drawer body  31  inserted into the cabinet  2  through the opening  21 , a drawer panel  33  fixed to the front surface of the drawer body  31  to open and close the drawer body  31 , and a drawer cover  35  for defining a top surface of the drawer body  31 . 
     Since the drawer panel  33  is fixed to the front surface of the drawer body  31 , the drawer panel  33  may also serve as a handle for drawing the drawer body  31  out of the cabinet  2 . 
     The drawer panel  33  may be provided with a display unit  331  for inputting control commands related to operation of the laundry treating apparatus  100  and displaying a message related to the operation and status of the laundry treating apparatus for the user. The display unit  331  may include a display panel for displaying a view, and may further include a speaker (not shown) configured to generate warning sound, notification sound, and the like. The display unit  331  may also serve as a control panel that may be touched by the user to execute the clothing processing operation. 
     The drawer body  31  may be inserted into the cabinet  2  through the opening  21  and have any shape as long as it can provide a space for accommodating the tub  4 .  FIG. 1  shows an example of the drawer body  31  which has a hexahedron shape with a hollow interior. 
     As shown in  FIG. 2 , the tub  4  includes a tub body  41  positioned in the drawer body  31  to store water, and a tub cover  43  for defining the top surface of the tub body  41 . The tub body  41  may have a cylindrical shape with an open top. A heater  411  for heating water may be provided in the tub body  41 . The heater  411  may not only heat water but also generate steam to supply steam into the tub body  41 . 
     The tub cover  43  may include an introduction port  431  allowing the inside of the tub body  41  to communicate with the outside of the tub body therethrough and a supply port  433  for introducing water into the tub body  41 . 
     The drawer cover  35  may include a first through hole  351  and a second through hole  353  allowing the inside of the drawer body  31  to communicate with the outside. The first through hole  351  is provided for introduction and retrieval of clothes, and the second through hole  353  may be provided to supply water necessary for washing clothes. 
     The introduction port  431  may be provided below the first through hole  351  provided in the drawer cover, and the supply port  433  may be provided below the second through hole  353  of the drawer cover. 
     The introduction port  431  is a means for supplying clothes into the tub body  41  or withdrawing clothes from the tub body  41  to the outside of the tub body. The introduction port  431  may be opened or closed by a door  45 . 
     The tub  4  having the above-described structure may be coupled to the drawer body  31  via a tub support portion  6 . The tub support portion  6  may include a first support portion  61  provided to the drawer body  31 , a second support portion  63  provided to the tub body  41 , and a connection portion  65  for connecting the first support portion and the second support portion. 
     The connection portion  65  may include a first connection portion  651  seated on the first support portion  61 , a second connection portion  653  for supporting the second support portion  63 , and a bar  655  for connecting the first connection portion and the second connection portion. 
     The first connection portion  651  may be shaped to be seated in the first support portion  61  so as to be movable in the first support portion  61 , and the second connection portion  653  may be shaped to support the second support portion  63  so as to be movable in the second support portion  63 . 
     The bar  655  may be arranged to form a right angle with the bottom surface of the cabinet  2  (to be parallel to the height direction Z of the cabinet and to form a right angle with the bottom surface of the drawer). 
     In the present invention, at least three tub support portions  6  are provided to couple the tub body  41  with the drawer body  31 , and the bar  655  is arranged to form a right angle with the bottom surface of the cabinet. Accordingly, the spacing between the tub cover  43  and the drawer cover  35  may be widened, compared to a case where the bar  655  is inclined at a predetermined angle with respect to the Z axis. 
     The tub support portion  6  provided in the present invention may minimize the possibility that the tub cover  43  will collide with the drawer cover  35  even when the tub body  41  vibrates inside the drawer body  31 . 
     When the bar  655  is arranged to be perpendicular to the bottom surface of the drawer, at least one of the first support portion  61  and the second support portion  63  may be detachably attached to the drawer body  31 . 
     When the tub support portion  6  has at least three support portion and both the first support portion  61  and the second support portion  63  are arranged so as not to be separated from the drawer body  31 , an operator who fixes the drawer body  31  to the drawer body  31  needs to insert the tub body  41  into the drawer body  31  such that the first support portion  61  does not interfere with the second support portion  63  and then rotate the tub body  41  to position the first connection portion  651  on the vertical line passing through the first support portion  61  to couple the first connection portion  651  to the first support portion  61 . 
     Arranging the bar  655  of the tub support portion at a right angle with respect to the bottom surface of the drawer may minimize the spacing S between the outer circumferential surface of the tub body  41  and the inner circumferential surface of the drawer body  31 , thereby minimizing the volume of the laundry treating apparatus  100 . However, such arrangement may deteriorate assimilability of the first connection portion  651  and the first support portion  61  which are connected through the above-described process. This disadvantage may be overcome by detachably providing the first support portion  61  to the drawer body  31 . 
     The drum  5  arranged in the tub  4  may be provided with a cylindrical drum body  51  having an opening  53  at the top thereof. Since the opening  53  is located below the introduction port  431 , clothes introduced through the introduction port  431  may be supplied to the drum body  51  through the opening  53 . 
     The bottom surface  57  and the circumferential surface  55  of the drum body  51  may be provided with a plurality of drum through holes  59  allowing the inside of the drum body  51  to communicate with the tub body  41  therethrough. 
     The drum body  51  is rotated in the tub body  41  by a drive unit M. The drive unit M may include a stator M 1  disposed outside the tub body  41  and fixed to the bottom surface the tub body, a rotor M 2  rotated by a rotating field provided by the stator, and a rotary shaft M 3  arranged to penetrate the bottom surface of the tub body  41  to connect the bottom surface  57  of the drum and the rotor M 2 . In this case, the rotary shaft M 3  may be arranged to form a right angle to the bottom surface of the tub body  41 . 
     The laundry treating apparatus  100  having the above-described structure supplies water to the tub  4  through a water supply unit  7  and discharges water stored in the tub  4  to the outside of the cabinet  2  through a drainage unit  8 . 
     As shown in  FIG. 2 , the water supply unit  7  may include a first water supply pipe  71  connected to the supply port  433  provided in the tub cover, a second water supply pipe  73  connected to a water supply source located outside the cabinet, and a connection pipe  75  fixed to the tub cover  43  and connecting the first water supply pipe and the second water supply pipe. 
     The first water supply pipe  71  connects the supply port  433  and the connection pipe  75  through the second through hole  353  provided in the drawer cover  35 , and may be formed as a corrugated tube to prevent the water supply pipe  71  from being separated from the connection pipe  75  when the tub  4  vibrates (see  FIG. 3 ). 
     The second water supply pipe  73  may also be formed as a corrugated tube to prevent the second water supply pipe  73  from being separated from the connection pipe  75  when the drawer  3  is drawn out of the cabinet  2 . The second water supply pipe  73  is opened and closed by a water supply valve  77 , which is controlled by a controller (not shown). 
     Unlike the example shown in  FIG. 2 , the water supply unit  7  may be provided with a single water supply pipe connecting the water supply source (not shown) arranged outside the cabinet and the supply port  433  provided in the tub cover. In this case, the water supply pipe may be formed as a corrugated tube. 
     The drainage unit  8  may include a drain pump  81  fixed to the drawer body  31 , a first drain pipe  83  for guiding water from the tub body  41  to the drain pump  81 , and a second water supply pipe  85  for guiding the water discharged from the drain pump  81  to the outside of the cabinet  2 . In this case, the second drain pipe  85  may be provided as a corrugated tube. 
     In the laundry treating apparatus  100  having the above-described structure, clothes are introduced into the drum  5 , water and a detergent are supplied to the tub  4 , and then the drum  5  is rotated through the drive unit M to wash the clothes. 
     The laundry treating apparatus  100  of the present invention having the above-described structure may further include a hot air supply unit  10  configured to supply hot air into the tub  4  or the drum  5 . That is, the hot air supply unit may be provided separately from the heater  411  to supply hot air to the tub  4  or the drum  5 . The hot air supply unit  10  may be supplied with water from the water supply unit  7  and heat the supplied water to supply the water to the tub  4  or the drum  5 . The hot air supply unit  10  may further include a hot air heater  11  configured to heat water in the hot air supply unit to generate steam, and a blowing fan  12  configured to supply hot air to the tub  4  or the drum  5 . 
     However, the hot air supply unit  10  may be configured in a circulation structure as long as it can supply hot air into the drum  5 . 
     In addition, a temperature sensor  700  configured to measure the temperature of water or air contained in the tub may be provided in the tub  4 . The temperature sensor  700  may be arranged near the heater  411  to check the temperature of the heater  411  immediately. The temperature sensor  700  may be a thermistor (NTC, PTC, CTR) thermal ferrite, or a metal thermometer. 
     The temperature sensor  700  may be provided at any position and with any configuration as long as it can measure the temperature of the inside of the tub  4  or the drum  5 . 
     The laundry treating apparatus  100  of the present invention may further include a detergent box  300  arranged outside the tub  4  to provide a space for storing the detergent. 
     The detergent box  300  may be arranged to receive water only from the tub  4 , not from the water supply unit  7 . Accordingly, elements such as a flow passage and a valve for directly connecting the detergent box  300  and the water supply unit  7  may be omitted. 
     In addition, the detergent box  300  may be provided to the drawer  3  or the cabinet  2 . That is, the detergent box  300  may be arranged outside the tub  4  and may be arranged anywhere as long as it can supply the detergent into the tub  4 . The detergent box  300  may be provided to the drawer  3  to allow the user to easily access the detergent box  300 , considering that the drawer  3  is drawn out of the cabinet  2 . When the detergent box  300  is provided to the drawer  3 , the detergent box  300  may be provided to the drawer panel  33 . This is because the drawer panel  33  is provided at the forefront of the laundry treating apparatus  100 , and allows the user to most easily reach the detergent box  300 . 
     Since the detergent box  300  is supplied with water only from the tub  4 , the laundry treating apparatus  100  of the present invention may further include a structure capable of supplying water from the tub  4  to the detergent box  300  and discharging the detergent from the detergent box  300  into the tub  4 . 
     To this end, the tub  4  may include a tub through hole  412  formed through an inner circumferential surface of the tub  4  and may further include a connection portion  400  communicating with the tub through hole  412  on one side thereof and with the detergent box  300  on an opposite side thereof. 
     Accordingly, the detergent box  300  may be supplied with water through the connection portion  400 , mix the supplied water with the detergent, and then discharge the mixture to the tub  4 . 
     Hereinafter, a description will be given of a manner in which water is supplied to the detergent box  300  and water and the detergent are discharged back to the tub  4  according to the above-described configuration, with reference to  FIG. 2 . 
     The drum  5  rotates when the laundry treating apparatus  100  performs at least one of a washing cycle for removing foreign substances from the clothes and a rinsing cycle for washing away the detergent and foreign substances from the clothes. 
     When the drum  5  rotates, the water in the tub  4  is moved along the inner circumferential surface of the tub  4  by the centrifugal force, and the water level on the inner circumferential surface of the tub  4  gradually increases. 
     When the drum  5  is rotated at a higher speed, the centrifugal force is further increased, and thus water in the tub  4  further moves along the inner circumferential surface of the tub  4  and flows into the connection portion  400  to reach the detergent box  300 . 
     When rotation of the drum  5  is maintained, water supplied into the detergent box  300  is increased and mixed with the detergent. Thereafter, when the rotation speed of the drum  5  is reduced or the drum  5  is stopped, the water level on the inner circumferential surface of the tub  4  is lowered. Then, the detergent and water in the detergent box  300  may be discharged into the tub  4  through the connection portion  400 . 
     Accordingly, since the detergent can be automatically supplied from the detergent box  300  to the tub  4 , a separate control means for supplying water to the detergent box  300  or adjusting the amount of the detergent to be discharged may be omitted. 
     The detergent stored in the detergent box  300  may correspond to at least one of a laundry detergent for removing foreign substances from the clothes and a fabric softener for increasing the degree of flexibility of the clothes. Accordingly, the detergent stored in the detergent box  300  should be appropriately introduced in the washing cycle, in which the laundry treating apparatus  100  removes foreign substances from the clothes, or the rinsing cycle, in which foreign substances and the detergent are washed away from the clothes after the washing cycle is completed, according to the type of the detergent. 
     That is, water in the tub  4  should be supplied to the detergent box  300  at an appropriate time, and the water and detergent in the detergent box  300  should be supplied to the tub  4  at an appropriate time. In other words, even if there is water contained in the tub  4 , the water inside the tub  4  should not be indiscriminately supplied to the detergent box  300 , and the detergent in the detergent box  300  should not be indiscriminately supplied into the tub  4 . 
     To this end, the tub through hole  412  may be arranged at a position higher than the maximum level at which water can be accommodated in the tub  4 , and the detergent box  300  may be arranged at a position higher than the maximum level at which water can be accommodated in the tub  4  when the drum  5  is stopped. 
     If the tub through hole  412  is provided at the lower end of the tub  4  or the detergent box  300  is arranged at the position of the bottom surface of the tub  4 , water may be supplied to the detergent box  300  immediately after water is supplied to the tub  4  through the water supply unit  7 , and the detergent in the detergent box  300  may be constantly discharged to the tub  4 . 
     If the connection portion  400  is arranged to communicate with the upper end of the detergent box  300 , the water and the detergent in the detergent box  300  cannot be supplied to the tub  4  when rotation of the drum  5  is reduced after the water is supplied to the detergent box  300 . 
     Accordingly, the connection portion  400  may be arranged to communicate with a lower portion of the detergent box  300 . 
       FIG. 3  shows the tub  4  and the detergent box  300  provided at the upper end of the drawer panel  33 . 
     Referring to  FIG. 3( a ) , the connection portion  400  is arranged to allow the upper end of the tub body  41  to communicate with the lower end of the detergent box  300  therethrough. 
     The detergent box  300  may be provided on one side of the upper end of the drawer panel  33  to avoid interference with the display unit  331  and may be arranged above the maximum water level of water accommodated in the tub body  41 . 
     Referring to  FIG. 3( b ) , the top of the detergent box  300  may include a lid  313  for opening and closing the detergent box  300 . 
     The inside of the detergent box  300  may be opened when the lid  313  is pulled up or rotated. 
     The connection portion  400  may include a first connection pipe  410  communicating with a lower portion of the detergent box  300 , a second connection pipe  420  communicating with an upper portion of the tub body  41 , and a communication hose  430  allowing the first connection pipe  410  and the second connection pipe  420  to communicate with each other. The second connection pipe  420  may be a pipe extending from the outer circumferential surface of the tub through hole  414  to the outside of the tub body  41 . 
     The communication hose  430  may be made of a rubber material and thus ensure the first connection pipe  410  and the second connection pipe  420  stably communicate with each other even when the drum  5  and the tub  4  vibrate. 
     Hereinafter, the structure of the detergent box  300  will be described in detail with reference to  FIG. 4 . 
     The detergent box  300  may be arranged at a position higher than the maximum level of water accommodated in the tub body  41  without any other device, and the connection portion  400  may be arranged at the lower end of the detergent box  300 . In this case, if the detergent stored in the detergent box  300  is a liquid detergent, the detergent may be introduced into the tub  4  through the connection portion  400  irrespective of whether the drum  5  is rotated. 
     Accordingly, in order to prevent such introduction, the detergent box  300  may have a structure which discharges water and the detergent from the detergent box  300  to the connection pipe  410  using the siphon effect when water more than a reference amount is introduced through the connection portion  400 . 
     Accordingly, even when a liquid detergent is provided in the detergent box  300 , the detergent may be prevented from being discharged by its own weight into the connection pipe  410  before the amount of water exceeds the reference amount. 
     Here, the reference amount may be defined as the minimum amount of water that may cause a siphon effect in the detergent box  300 . 
     The detergent box  300  may include a body portion  320  configured to provide a space for storing the detergent and having an opening  323  at the top thereof, a housing  310  in which the body portion is detachably accommodated, and a housing through hole  311  communicating with the connection portion  400  through a lower portion of the body portion  320 . The body portion  320  may include a discharge pipe  321  protruding from a lower portion of the body portion  320  toward the opening  323  and provided therein with a hollow allowing the housing  310  and the body portion  320  to communicate with each other, and a discharge pipe cover  322  into which a part of the discharge pipe  321  is inserted to guide the water and detergent into the hollow when the amount of water introduced into the body portion  320  is greater than or equal to a reference amount. 
     When the body portion  320  is accommodated in the housing  310 , the opening  323  of the body portion  320  may be arranged below the upper end of the side surface of the housing  310 . 
     The housing  310  may be provided with a housing coupling portion  312  to be coupled to either the drawer  3  or the cabinet  2 . 
     The housing coupling portion  312  may be a plate extending from at least one of a side surface and a bottom surface of the housing  310 . 
     The housing coupling portion  312  may have a hollow therein so as to be coupled with a bolt or the like. 
     Accordingly, the body portion  320  may be stably accommodated in the housing  310 , 
     Water rising along the side surface of the housing  310  may flow into the opening  323  of the body portion  320 . 
     Hereinafter, introduction of water from the tub  4  into the detergent box  300  and discharge of water and the detergent back to the tub  4  will be described with reference to  FIGS. 4( b ) and 4( c ) . 
     When the drum  5  rotates at a first revolutions per minute (rpm), the water accommodated in the tub  4  rises up to the position where the tub through hole  412  provided in the inner circumferential surface of the tub  4  is arranged. 
     When the drum  5  rotates at a speed higher than or equal to the first rpm, water in the tub  4  is introduced into the housing through hole  311  through the connection portion  400  via the tub through hole  414 . Here, the first rpm may be defined as an rpm at which the water accommodated in the tub  4  rises up to the tub through hole  412  provided in the tub body  41 . 
     The tub through hole  412  may be provided at a position where water contacts the tub body  41  when the drum  5  rotates at the first rpm. 
     Thereafter, when the drum  5  rotates at a second rpm higher than the first rpm, the water in the tub  4  may further rise up the inner circumferential surface (the tub body) of the tub. Thus, the water may contact the lower end of the discharge pipe  321  provided at the lower portion of the body portion. That is, it may be construed that the discharge pipe  321  is provided at a height at which the pipe contacts water when the drum  5  rotates at the second rpm, and is spaced apart from the housing through hole  311  by a difference between the level of water introduced when the drum  5  rotates at the first rpm and the level to which the water rises when the drum  5  rotates at the second rpm. 
     The water level that water introduced into the housing  310  reaches when the drum  5  rotates at the second rpm, may be defined as a first (1st) level. 
     When the drum  5  rotates at a third rpm higher than the second rpm, the water inside the tub  4  is further moved to the inner circumferential surface (tub body) of the tub by stronger centrifugal force and thus a larger amount of water is introduced into the housing  310 . 
     Accordingly, when the drum  5  rotates at the third rpm, the water in the tub  4  flows into the housing  310  through the connection portion  400  and rises up to the free end of the discharge pipe  321 . That is, the water supplied to the housing  310  comes into contact with the discharge pipe cover  322 . 
     When the drum  310  rotates at the third rpm or a higher speed, the water supplied to the housing  310  flows into the body portion  320  through the discharge pipe  321  and the discharge pipe cover  322 . 
     In the body portion  320 , the detergent is stored at a second (2nd) level that is higher than the first level and lower than the free end of the discharge pipe  321  or the upper end portion of the discharge pipe cover  322 . 
     When the water is supplied to the body portion  320 , the water and the detergent are mixed, and the level of the water and detergent in the body portion  320  further rises up to a third (3rd) level corresponding to the free end of the discharge pipe  321  or the upper end portion of the discharge pipe cover. 
     Then, when the drum  5  is rotated at a speed lower than the third rpm or is stopped, the water accommodated in the body portion  320  begins to be discharged through the free end of the discharge pipe  321  via the inner circumferential surface of the discharge pipe cover  322  and the outer circumferential surface of the discharge pipe  321 . At this time, the siphon effect occurs, and thus the detergent and water accommodated in the body portion  320  are entirely discharged to the housing  310  through the discharge pipe  321 . The water and the detergent accommodated in the housing  310  are discharged to the tub  4  through the connection portion  400  via the housing through hole  311 . 
     Thus, the detergent box  300  may be automatically supplied with water from the tub  4  and discharge the supplied water to the tub  4  without any means for supplying water through the water supply pipe or a control means for controlling discharge of the detergent. 
       FIG. 4( c )  shows another embodiment of the detergent box  300 . 
     Since the body portion  320  is detachably provided in the housing  310 , a predetermined space may be provided between the outer circumferential surface of the body portion  320  and the inner circumferential surface of the housing  310 . That is, the body portion  320  may be spaced apart from the housing  310  by a predetermined distance. 
     When the body portion  320  is accommodated in the housing  310 , the side surface of the housing  310  may be arranged higher than the opening  323 . 
     If water supplied to the housing  310  is immediately introduced into the discharge pipe  321 , the water may not be properly mixed with the detergent accommodated in the body portion  320 . Accordingly, a buoyancy type body check valve  324  may be provided under the discharge pipe  321 . 
     The body check valve  324  may be made of a rubber material that may completely close the hollow of the discharge pipe  321  and may be rotatably hinged to the lower portion of the body portion  320 . 
     The body check valve  324  may be a buoyancy type check valve having a specific gravity less than that of water. 
     Thus, when the drum  5  rotates at the second rpm, the water supplied to the housing  310  reaches the first (1st) level, and buoyancy may be applied to the body check valve  324  to close the discharge pipe  321 . Thereafter, when the drum  5  starts to rotate at the third rpm or a higher speed, the water supplied to the housing  310  may begin to rise along the outer circumferential surface of the body portion  320  and flow into the body portion  320  through the opening  323 . 
     The water introduced into the body portion  320  through the opening  323  may be entirely mixed with the detergent contained at the second (2nd) level in the body portion  320 . When the supplied water reaches the third (3rd) level, the siphon effect may occur. 
     Thereafter, when the drum  5  is slowed from the third rpm to the second rpm or a lower speed or is stopped, the water and the detergent accommodated in the body portion  320  flows into the free end of the discharge pipe  321  along the discharge pipe cover  322  and the outer circumferential surface of the discharge pipe  321  and comes into contact with the body check valve  324 . 
     The body check valve  324  opens the discharge pipe  321  due to the weight of the water and the detergent. The water and the detergent may all pass through the discharge pipe  321  and be discharged to the tub  4  through the housing through hole  311  along the connection pipe  410 . 
       FIG. 5  shows installation positions of the detergent box  300  and the tub  4 , and installation heights of the discharge pipe  321  and the discharge pipe cover  322  of the detergent box  300 . 
     The detergent box  300  is provided at a position higher than the maximum level that water in the tub body  41  reaches when the drum  5  is stopped, and the second connection pipe  430  communicating with the tub through hole  412  is arranged at an upper portion of the tub body  41 . 
     Here, as described above, the tub through hole  412  and the second connection pipe  430  may be arranged at a water level at which water in the tub  4  can contact the tub body  41  when the drum rotates at the first rpm. The first connection pipe  410  may be arranged at a lower portion of the detergent box  300 , and the lower portion of the discharge pipe  321  may be arranged at a height (1st level) which the water supplied to the housing  310  reaches when the drum  5  rotates at the second rpm. The free end of the discharge pipe  321  and the upper portion of the discharge pipe cover  322  are arranged at a height (3rd level) which water supplied to the housing  310  reaches when the drum  5  rotates at the third rpm. 
     Hereinafter, the structure of the tub  4  for accurately supplying water to the housing  310  according to the rpm of the drum  5  will be described in detail with reference to  FIGS. 6 and 7 . 
     When the drum  5  rotates in the tub  4 , the drum  5  may momentarily severely vibrate due to, for example, maldistribution of clothes. The momentary sever vibration of the drum  5  may cause water accommodated in the tub  4  to momentarily gather in a space between the tub body  41  and the tub cover  43 . As a result, a large amount of water may be momentarily supplied to the housing  310 , causing an unexpected siphon effect in the body portion  320 . 
     Accordingly, it may be necessary to provide a configuration in which water is supplied to the detergent box  300  only by a constant rise of the water level in the tub  4  that is generated by rotation of the drum  5 , not by vibration of the drum  5 . 
       FIG. 6  shows an insertion portion  435  which may be provided in the tub cover  43  to cause water to be supplied to the detergent box  300  only by a constant water level rise in the tub  4  generated by rotation of the drum  5 . 
     The tub cover  43  may include a cover body  434  positioned at the top of the tub body  41  to form a top surface of the tub body  41 , and an insertion portion  435  protruding from an outer circumferential surface of the cover body  434  and contacting the inner circumferential surface of the tub body  41 . 
     The tub body  41  includes a first protrusion  415  formed on an upper portion of the outer circumferential surface thereof and a second protrusion  417  spaced apart from the first protrusion  417 . The tub cover  43  includes a first fastening portion  437  inserted into and fastened to a gap between the first protrusion and the second protrusion, and a second fastening portion  417  spaced apart from the first fastening portion and seated on the outer circumferential surface of the second protrusion  417 . Thus, the tub body  41  and the tub cover  43  are coupled to each other. 
     The insertion portion  435  may be spaced apart from the first fastening portion  437  so as to face the center of the tub  4  and protrude toward the bottom surface of the tub  4 . 
     Specifically, when the tub body  41  and the tub cover  43  are coupled to each other, the insertion portion  435  may be spaced apart from the tub body  41  by a predetermined distance so as to face the position where the drum  5  is arranged in the tub body  41  and may protrude to a distance long enough to shield the tub through hole  412 . 
     Accordingly, even when vibration occurs in the drum  5  to cause the water in the tub  4  to rise toward the tub through hole  412  to generate a swell, the insertion portion  435  may block the swell, thereby preventing water from being discharged from the tub through hole  412 . 
     That is, only when the drum  5  rotates and the water accommodated in the tub  4  rises to the tub body  41  such that the water level is maintained, the water accommodated in the tub may flow into the gap between the tub body  41  and the insertion portion  435  and be discharged through the second connection pipe  430 . 
     This may prevent the water accommodated in the tub  4  from being unintentionally introduced into the detergent box  300 , thereby preventing the siphon effect from occurring in the detergent box  300 . 
       FIG. 7  shows a resistive rib that may be provided to the tub body  41  to cause water to be supplied to the detergent box  300  only by a constant water level rise in the tub  4  generated by rotation of the drum  5 . 
     The inner circumferential surface of the tub  4  may be provided with first resistive ribs  413  protruding from both sides of the surface having the tub through hole  412  to generate resistance against water rotating along the inner circumferential surface of the tub such that water can flow into the tub through hole  412  only when the drum rotates at the first rpm or a higher speed. 
     That is, when the drum  5  rotates at a speed lower than the first rpm, and the water accommodated in the tub  4  temporarily contacts the inner circumferential surface of the tub body  41  due to momentary vibration of the drum  5 , the first resistive ribs  413  may reduce the kinetic energy of the water. 
     Accordingly, the first resistive ribs  413  may prevent the water accommodated in the tub  4  from unintentionally flowing into the tub through hole  412  and moving to the detergent box  300 . 
     In addition, when the drum  5  temporarily rotates at the first rpm or a higher speed, the first resistive ribs  413  may resist against the water moving along the inner circumferential surface of the tub body  41 , thereby preventing the water from being discharged to the tub through hole  412 . 
     The inner circumferential surface of the tub may further include a second resistive rib  414  arranged under the tub through hole  412  and protruding toward the bottom surface of the tub. Here, the second resistive rib  414  may be arranged in parallel with the first resistive ribs  413 . 
     The first resistive ribs  413  and the second resistive rib  414  may collide with water moving in contact with the tub body  41  to reduce the kinetic energy of the water, and may also serve to hold a part of the water so as not to rotate, using the surface tension. 
     Thereby, even when the drum  5  temporarily rotates at a speed higher than or equal to the first rpm or a speed lower than the first rpm, and excessive vibration occurs in the drum  5  to cause the water in the tub  4  to gather in the tub body  41  and rise up, the first resistive ribs  413  and the second resistive rib  414  may effectively prevent the water from being discharged into the tub through hole  412 . 
     In addition, the first resistive ribs  413  and the second resistive rib  414  may allow the water to be supplied to the detergent box  300  only when the drum  5  persistently rotates at the first rpm or a higher speed. Accordingly, the rpm of the drum  5  may be precisely controlled to allow water to flow into the detergent box  300  at an appropriate time to supply the detergent to the tub  4 . 
     Since the body portion  320  and the housing  310  are detachably provided to the detergent box  300  shown in  FIG. 4 , there may be a certain gap between the body portion  320  and the housing  310 . 
     Accordingly, in the case of  FIG. 4( b ) , when a large amount of water is supplied to the housing  310 , a part of the water may flow into the discharge pipe  321 , but the remaining water may flow into a space between the inner circumferential surface of the housing  310  and the outer circumferential surface of the body portion  320 . Then, the water introduced into the space between the inner circumferential surface of the housing  310  and the outer circumferential surface of the body portion  320  may rise to a position at or above the first (1st) level. When more water is supplied to the housing  310 , the water may be introduced into the body portion  320  through the opening  323 . Thereafter, when rotation of the drum  5  is stopped or slowed to the second rpm or a lower speed, the siphon effect occurs in the body portion  320  and the detergent and water are discharged through the discharge pipe  321 . At the same time, the water introduced into the space between the housing  310  and the body portion  320  begins to descend. 
     Here, when all the water introduced into the space between the housing  310  and the body portion  320  descends and the water level is lowered to or below the first (1st) level, the detergent and water discharged from the discharge pipe  321  due to the siphon effect temporarily undergoes interruption of the siphon effect. 
     That is, when the water introduced into the space between the housing  310  and the body portion  320  descends due to decrease of the rpm of the drum  5  to the second rpm or a lower speed, the siphon effect is persistently maintained in the discharge pipe  321  and the detergent and the water are discharged together to the discharge pipe  321  until the water comes into contact with the outlet portion of the discharge pipe  321 , which is immediately before the first (1st) level. 
     However, when all the water introduced into the space between the housing  310  and the body portion  320  descends to or below the first (1st) level and begins to be separated from the lower end (outlet) of the discharge pipe  321 , a pressure change temporarily occurs at the lower end (outlet) of the discharge pipe  321 , and the siphon effect is interrupted. 
     The interrupted siphon effect occurs again when the water level in the housing  310  falls to or below the first (1st) level and the pressure at the lower end of the discharge pipe  321  remains unchanged. However, the amount of fluid discharged by the siphon effect is smaller than before the siphon effect was interrupted, and accordingly a certain amount of detergent and water may be retained in the body  310 . 
     Even in the case of  FIG. 4( c ) , when a large amount of water is supplied to the housing  310 , the water is blocked by the body check valve  324  from flowing into the discharge pipe  321 , and may be introduced into the space between the inner circumferential surface of the housing  310  and the outer circumferential surface of the body portion  320  and moved to the opening  323 . 
     Thereafter, when a large amount of water is introduced through the opening  323  and rises up to the third (3rd) level and the rpm of the drum  5  is reduced, the siphon effect occurs, and the detergent and water in the body portion  320  begins to be discharged into the discharge pipe  321 . At the same time, the level of the water introduced into the space between the outer circumferential surface of the body portion  320  and the inner circumferential surface of the housing  310  is lowered because water is discharged from the housing  310 . 
     Here, when the level of the water introduced into the space between the inner circumferential surface of the housing  310  and the outer circumferential surface of the body portion  320  is lowered and the water level in the housing  310  is lowered to the first (1st) level or a lower level, contact between the lower end (outlet) of the discharge pipe  321  and the water stored in the housing  310  is broken and the siphon effect in the discharge pipe  321  is momentarily interrupted. 
     That is, at the moment when the water having risen in the housing  310  to or above the first (1st) level and flowed into the space between the outer circumferential surface of the body  310  and the inner circumferential surface of the housing  320  is lowered to or below the first (1st) level, a pressure change occurs at the lower end (outlet) of the discharge pipe  321 . Thereby, the siphon effect in the discharge pipe  321  is interrupted and discharge of the water and the detergent is temporarily interrupted. 
     Thereafter, when the water level in the housing  310  is lowered and the pressure at the lower end (outlet) of the discharge pipe  321  is maintained, the siphon effect occurs again, and the detergent and the water in the body portion  320  are discharged into the discharge pipe  321  again. 
     However, the restarted siphon effect is weaker than the siphon effect before the interruption, and thus a certain amount of water and detergent remains in the body portion  320 . 
     Accordingly, to persistently keep the siphon effect in the discharge pipe  321  uninterrupted, the pressure at the lower end (outlet) of the discharge pipe  321  needs to be kept constant. 
     To this end, the lower end of the discharge pipe  321  needs to be maintained not to contact water because the pressure will not be changed by the change in water level in the housing  310  if the lower end the discharge pipe  321  does not contact the water from the beginning. 
       FIG. 8  illustrates an embodiment in which a block unit is additionally provided to prevent water supplied into the housing  310  from contacting the lower end of the discharge pipe  321 . 
     Like the detergent box  300  shown in  FIG. 4 , the detergent box  300  may include a body portion  312  configured to provide a space for storing a detergent and having an opening at the top thereof, a housing  310  in which the body portion is detachably accommodated, a housing through hole  311  penetrating a lower portion of the housing such that water is introduced or the detergent and water are discharged together therethrough, a discharge pipe  321  protruding from a lower portion of the body toward the opening and provided therein with a hollow for discharging the detergent, and a discharge pipe cover  322  into which a part of the discharge pipe is inserted to guide water and the detergent into the hollow when the amount of water introduced into the body portion is greater than or equal to a reference amount. The detergent box may further include a block unit configured to communicate with the discharge pipe  321  and provide a certain space between the lower portion of the body portion  320  and the bottom surface of the housing  310  to prevent water introduced into the housing  310  from contacting the discharge pipe  321 . 
     The block unit  330  may include a block body  331  accommodated in the housing  310 , at least a part of the body portion  320  being accommodated in the block body, and a block through hole  332  formed in a bottom surface of the block body  331  such that the detergent discharged from the discharge pipe  321  is discharged into the housing  310 . 
     The block unit  330  may further include a block check valve  333  arranged outside the bottom surface of the block body  331  to shield the block through hole  332 . 
     The block check valve  333  may be a buoyancy type check valve. Thus, when the water in the housing  310  is introduced and brought into contact with the block check valve  333 , the block check valve  333  may close the block through hole  332 . 
     The block check valve  333  may be hinged to the lower surface of the block body  331  or may be fixedly arranged. 
     That is, the block check valve  333  may be coupled in any structure as along as it keeps the block through hole  332  open at normal times and is caused to close the block through hole  332  by buoyancy when water is introduced into the housing  310  and brought into contact with the block check valve. The block check valve  333  may be made of a rubber material. 
     In addition, for coupling between the body portion  320  and the block unit  330 , a body coupling portion  325  may be provided to the lower end of the body portion  320 , and a block coupling portion  336  capable of being coupled with the body coupling portion  325  may be provided on the bottom surface of the block unit  330 . 
     The block coupling portion  336  may be formed as a groove into which the body coupling portion  325  is press-fitted. 
     Thus, the block body  331  may accommodate the body portion  320  from the outside and provide a predetermined space between the bottom surface of the body portion  320  and the bottom surface of the block body  331 , such that water introduced into the housing  310  may be prevented from flowing into the predetermined space. 
     That is, the block body  331  may be configured such that only air can be contained in the space between the lower surface of the body portion  320  and the bottom surface of the block body, and the water supplied into the housing  310  cannot be introduced into the space. 
     Hereinafter, a structure in which the siphon effect may be kept uninterrupted in the discharge pipe  321  through the block unit  330  will be described with reference to  FIG. 9 . 
     Referring to  FIG. 9( a ) , the drum  5  is rotated at a speed higher than or equal to the first rpm and lower than or equal to the second rpm, and thus water starts to flow into the housing  310 . 
     Referring to  FIG. 9( b ) , water introduced into the housing  310  starts to further rise in the housing  310  and pushes up the block check valve  331  to close the lower end (outlet) of the discharge pipe  321 . 
     Thereafter, when the drum  5  is rotated at a speed higher than the second rpm, more water flows into the housing  310 , and thus the water rises in the space between the body portion  320  and the housing  310 . Here, the water introduced into the housing  310  cannot flow into the block unit  330 , and accordingly the lower portion of the discharge pipe  321  does not contact the water. 
     Referring to  FIG. 9( c ) , the drum  5  is rotated at a speed higher than the third rpm, and thus water introduced into the housing  310  flows into the body  310  through the opening  323  and is supplied until the water reaches the third (3rd) level. 
     Referring to  FIG. 9( d ) , the siphon effect occurs in the discharge pipe  321 , and thus the detergent and water in the body portion  320  are discharged to the block unit  330 . The detergent and water discharged to the block unit  330  press the check valve  331  by their own weights. Then, when the water level in the housing  310  is lowered, the check valve  331  is opened, and both the water and the detergent in the block unit  330  are discharged to the tub  4  through the first connection pipe  410  via the housing through hole  311 . 
     In this process, when the siphon effect occurs in the discharge pipe  321 , the pressure at the lower end (outlet) of the discharge pipe  321  is kept unchanged by the block unit  330 , and accordingly the siphon effect may be continued without being interrupted. 
     Accordingly, the water and detergent may be entirely discharged to the tub  4  by the block unit  330  without any water or detergent remaining in the body  310 . 
       FIG. 10  illustrates another embodiment of the block unit  330 . 
     The block unit  330  of  FIG. 10  does not fully accommodate the body portion  320 , unlike the block unit of  FIG. 9 , but is configured to accommodate only a part of the body portion that is provided with the discharge pipe  321 . 
     Specifically, the block unit  330  may include a block barrel  334  extending from a lower end of the body portion  320  having the discharge pipe  321 . The block barrel  334  may include a communication hole provided at one end to communicate with the discharge pipe  321  and a block through hole  332  provided at an opposite end to communicate with the housing  310 . 
     A block check valve  333  configured to open and close the block through hole  332  may be provided on the outer circumferential surface of the block through hole  332 . 
     Similarly, the block unit  330  shown in  FIG. 10  may prevent change in pressure at the outlet (lower end) of the discharge pipe  321  to prevent the discharge pipe  321  from making a direct contact with water introduced into the housing  310 . 
     Accordingly, the water introduced into the housing  310  may raise the block check valve  333  to close the block through hole  332  and may flow into the opening  323  to generate and persistently maintain the siphon effect in the discharge pipe  321 . 
     Accordingly, the block unit  330  may cause all the water and detergent in the body portion  320  to be discharged to the housing  310 . 
     On the basis of the above-described configuration, the laundry treating apparatus of the present invention may include a water supply step S 1  of supplying water to the tub  4 , a washing step S 2  of rotating the drum  5  at an rpm lower than the first rpm, and a detergent box water supply step S 3  of rotating the drum at an rpm higher than or equal to the first rpm to move a part of water stored in the tub corresponding to a reference amount or a larger amount to the detergent box  300 , the detergent box water supply step being initiated before or during the washing step. 
     Here, the first rpm is set to an rpm at which centrifugal force causing at least a part of the water stored in the tub  4  to rise up even in the detergent box through the connection portion  400  is provided to the water. Specifically, a third rpm, which is higher than the first rpm, may be set as an rpm at which the siphon effect occurs in the detergent box. The rpm higher than or equal to the first rpm may correspond to an rpm higher than or equal to the third rpm. Further, the reference amount may be set to the amount of water at which the siphon effect starts to occur in the detergent box. 
     The washing step may include a first washing step S 2 - 1  of rotating the drum  5  at an rpm lower than the first rpm to create a water stream in the tub, a drainage step S 2 - 2  of discharging the water stored in the tub  4  after completion of the first washing step, a second water supply step S 2 - 3  of supplying water to the tub  5  after completion of the drainage step, and a second washing step S 2 - 4  of rotating the drum at an rpm lower than the first rpm to create a water stream in the tub. 
     The detergent box water supply step S 3  may include a step of determining a time at which the detergent can be introduced into the tub  4 , and then supplying the detergent to the tub  4  when the time is reached. 
     The time at which the detergent can be introduced into the tub  4  may be a time before the first washing step S 2 - 1  is initiated if a detergent for removing foreign substances from clothes is accommodated in the detergent box  300 , or correspond to the second washing step S 2 - 3  if a fabric softener for increasing the degree of flexibility of the clothes is accommodated in the detergent box  300 . 
     The water supply step S 1  is a step of supplying water to the tub  4  such that a water level higher than the bottom surface of the drum  5  is maintained. 
     If a detergent for removing foreign substances from the clothes is accommodated in the detergent box  300 , the detergent box water supply step S 3  may be performed before the first washing step S 2 - 2  is initiated after completion of the water supply step. 
     Since the detergent box water supply step S 3  is performed before initiation of the first washing step when the detergent box  300  contains the detergent, the detergent may be supplied to the tub  4  before the first washing step S 2 - 1 . Accordingly, foreign substances may be removed from the clothes with the detergent and water in the first washing step S 2 - 1 . 
     That is, the first washing step S 2 - 1  may be understood as a step of separating foreign substances from the clothes using the detergent stored in the detergent box  300 . 
     The second water supply step S 2 - 3  is a step of supplying water to the tub again such that a water level higher than the bottom surface of the drum is maintained. 
     When a detergent for removing foreign substances from the clothe is accommodated in the detergent box  300 , the second water supply step S 2 - 3  may be understood as a step of supplying water for the rinsing cycle of washing away the detergent and foreign substances from the clothes. 
     When a fabric softener for increasing the degree of flexibility of the clothes is accommodated in the detergent box  300 , the detergent box water supply step S 3  may be performed before the second washing step S 2 - 4  is initiated after completion of the second water supply step S 2 - 3 . 
     Accordingly, since the detergent box water supply step is performed before initiation of the second washing step S 2 - 4  when the fabric softener is contained in the detergent box  300 , the second washing step S 2 - 4  may be provided as a step of supplying the fabric softener stored in the detergent box to the tub to increase the degree of flexibility of the clothes. 
     Accordingly, the second washing step S 2 - 4  may be set as a step of increasing the degree of flexibility of the clothes by supplying the detergent stored in the detergent box to the tub. 
     The laundry treating apparatus  100  of the present invention may omit the water supplying means which communicates with the water supply unit  7  to separately supply water to the detergent box  300 . That is, the detergent contained in the detergent box  300  may be automatically discharged to the tub  4  by controlling the rpm of the drum  5  alone in order to separate foreign substances from the clothes or to increase the degree of flexibility of the clothes. 
     The present invention may be embodied in various forms without departing from the scope of the invention. Accordingly, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.