WO2006129963A2

WO2006129963A2 - Dishwasher and controlling method thereof

Info

Publication number: WO2006129963A2
Application number: PCT/KR2006/002090
Authority: WO
Inventors: Byung-Hwan Ahn; Soung-Bong Choi; Deug-Hee Lee; Hung-Myong Cho; Hyeok-Deok Kim; Seong-Hae Jeong
Original assignee: Lg Electronics Inc.
Priority date: 2005-05-31
Filing date: 2006-05-30
Publication date: 2006-12-07
Also published as: EP1885230A2; US20090139544A1; EP1885230A4; WO2006129963A3

Abstract

A dishwasher is provided. The dishwasher includes a tub (18), a stream generator (20), and a connecting passage. The tub stores dishes. The steam generator generates (20) steam to be supplied into the tub (18). The connecting passage connects a discharging end of the steam generator (20) to an inside of the tub (18).

Description

DISHWASHER AND CONTROLLING METHOD THEREOF

Technical Field

[1] The present invention relates to a dishwasher.

Background Art

[2] A dishwasher is a home appliance that sprays high-pressure wash liquid within a tub to wash and remove food residue and other impurities left on surfaces of dishes. A filter filters the food residue from the wash liquid to recycle the latter, and detergent is dissolved into the wash liquid to facilitate the removal of food residue. [3] In order to improve the above dishwashing process, the following dishwasher functions have been developed. [4] First, by heating wash liquid to aid in dissolving the detergent, overall dishwashing effectiveness can be improved. Also, by heating wash liquid, the wash liquid can more easily remove glutinous rice and other hardened food residue. [5] Furthermore, by dividing the wash cycle of a dishwasher into a pre-wash cycle and a main wash cycle, the pre-wash cycle soaks hardened food residue, so that it can be more easily removed in the main wash cycle. [6] Another method being employed is removing germs and sterilizing dishes by emitting ultraviolet light onto the surfaces of dishes. [7] However, despite the above devised methods according to the related art, the problem of increasing dishwashing efficiency remains. Especially in oriental households, where in many cases, the staple food is glutinous rice, the latter is difficult to effectively remove from dishes, exasperating the problem of dishwashing efficiency.

Even the use of hot water to soak food residue cannot completely obviate the above problem. [8] Also, because soaking requires a prolonged amount of time, it lengthens the duration of the wash cycle. [9] Furthermore, because a dishwasher is used repeatedly, food deposits accumulate and harden on the inner surfaces of the tub, and a strong smell is emitted when this hardened residue is contaminated by germs. Furthermore, even after dishes are washed, food residue and germs still remain on them. Thus, the overall washing efficiency of a dishwasher is reduced. [10] Additionally, dishwashers according to the related art sprinkle detergent onto dishes after which they are rinsed by wash liquid. Thus, the detergent is inefficiently used.

Disclosure of Invention

Technical Problem [11] To solve the above problem, the present invention provides a dishwasher and a controlling method thereof that easily remove food deposits hardened on dishes, increasing the efficiency of washing dishes.

[12] Another object of the present invention is to provide a dishwasher and a controlling method thereof that quickly soak food deposits on dishes, so that the duration of the washing cycle of the dishwasher is reduced to provide more convenience to a user.

[13] A further object of the present invention is to provide a dishwasher and a controlling method thereof that improve the washing efficiency of the dishwasher.

[14] A still further object of the present invention is to provide a dishwasher and a controlling method thereof that increase surface active efficiency of detergent, so that dishwashing efficiency increases. Technical Solution

[15] According to an aspect of the present invention, there is provided a dishwasher including: a tub for storing dishes; a steam generator for generating steam to be supplied into the tub; and a connecting passage for connecting a discharging end of the steam generator to an inside of the tub.

[16] According to another aspect of the present invention, there is provided a controlling method of a dishwasher, including: preparing a dishwasher including a tub for storing dishes, a steam generator for generating steam to be supplied into the tub, and a connecting passage for connecting a discharging end of the steam generator to an inside of the tub; supplying steam into the tub from the steam generator; and spraying wash liquid onto the dishes.

[17] According to a further aspect of the present invention, there is provided a controlling method of a dishwasher, including: preparing a dishwasher including a tub for storing dishes, a steam generator for generating steam to be supplied into the tub, and a connecting passage for connecting a discharging end of the steam generator to an inside of the tub; supplying steam into the tub from the steam generator; spraying wash liquid onto the dishes; spraying the wash liquid again and determining whether to repeat the supplying of the steam; and alternately repeating the spraying of the wash liquid and the supplying of the steam when the determining determines to repeat the supplying of the steam.

[18] According to an additional aspect of the present invention, there is provided a controlling method of a dishwasher, including: preparing a dishwasher including a tub for storing dishes, a steam generator for generating steam to be supplied into the tub, and a connecting passage for connecting a discharging end of the steam generator to an inside of the tub; performing a main wash cycle through spraying wash liquid mixed with detergent for washing the dishes; and supplying the steam from the steam generator into the tub in at least one of a cycle before and after the main wash cycle. Advantageous Effects

[19] An advantage of the dishwasher and controlling method thereof according to the present invention is that they can easily remove food residue hardened on dishes to improve washing efficiency of the dishwasher. [20] Another advantage of the dishwasher and controlling method thereof according to the present invention is that soaking of dishes is performed quickly so that the duration of the dishwasher's washing cycle is reduced, thereby reducing the work performed by the pump and power consumption of the dishwasher. [21] A further advantage of the dishwasher and controlling method thereof according to the present invention is that they improve sterilizing efficiency of dishes for improved hygiene thereof. [22] A still further advantage of the dishwasher and controlling method thereof according to the present invention is that they satisfactorily clean dishes physically, chemically, and biologically at the same time, so that food residue can be more thoroughly removed from dishes. [23] An additional advantage of the dishwasher and controlling method thereof according to the present invention is that the spraying of wash liquid and then the supplying of steam is repeated, improving the cleanliness of dishes. [24] Another added advantage of the dishwasher and controlling method thereof according to the present invention is that hot steam can be discharged during a plurality of cycles, so that the efficiency of the dishwasher increases. [25] A further added advantage of the dishwasher and controlling method thereof according to the present invention is that they increase the dissolving of detergent in wash liquid to increase the efficiency of the dishwasher.

Brief Description of the Drawings [26] Fig. 1 is a perspective view of a dishwasher according to the first embodiment of the present invention. [27] Fig. 2 is a perspective view of a dishwasher according to the first embodiment of the present invention with its door open.

[28] Fig. 3 is a sectional view of the dishwasher in Fig. 1 taken along line I-I'.

[29] Fig. 4 is a flowchart showing a controlling method of a dishwasher according to the first embodiment of the present invention. [30] Fig. 5 is a flowchart showing a controlling method of a dishwasher according to the second embodiment of the present invention. [31] Fig. 6 is a flowchart showing a controlling method of a dishwasher according to the third embodiment of the present invention. [32] Fig. 7 is flowchart showing a controlling method of a dishwasher according to the fourth embodiment of the present invention.

[33] Fig. 8 is flowchart showing a controlling method of a dishwasher according to the fifth embodiment of the present invention.

[34] Fig. 9 is flowchart showing a controlling method of a dishwasher according to the sixth embodiment of the present invention.

[35] Fig. 10 is flowchart showing a controlling method of a dishwasher according to the seventh embodiment of the present invention. Best Mode for Carrying Out the Invention

[36] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[37] Fig. 1 is a perspective view of a dishwasher according to the first embodiment of the present invention.

[38] Referring to Fig. 1, a dishwasher according to the present invention includes a case

1 forming an outer shape of the dishwasher and an opening at a front thereof, a door 2 sealing the opening at the front of the case 1, and a control panel 3 provided above the door 2, for displaying and controlling the operation of the dishwasher.

[39] In detail, the control panel 3 includes a power switch 5 for switching power to the dishwasher on and off, a door handle 4 used to open and close the door 2, controls 7 for implementing a predetermined operation of the dishwasher according to a user's inputted commands, and a display 8 for displaying the operation of the dishwasher.

[40] Fig. 2 is a perspective view of a dishwasher according to the first embodiment of the present invention with its door open.

[41] Referring to Fig. 2, a tub 18 for containing wash liquid inside the dishwasher is disposed therein, and a sump 16 disposed at the bottom of the tub 18 for collecting, filtering, and re-circulating wash liquid to be sprayed.

[42] In detail, the inside of the tub 18 includes an upper dish rack 11 and a lower dish rack 12 for placing dishes in, and an upper spray arm 14 and top spray nozzle 24 for spraying wash liquid towards the upper dish rack 11, and a lower spray arm 15 for spraying wash liquid towards the lower dish rack 12. The inner surfaces of the tub 18 have a rail 13 extending from front to rear in order to slide the upper dish rack 11 thereon. A filter 17 is disposed at the bottom of the tub 18 to filter impurities from wash liquid.

[43] A wash liquid passage 19 is provided at an inner side surface of the tub 18, for supplying wash liquid to the upper spray arm 14 and the top spray nozzle 24. [44] The door 2 is coupled to the case 1 through a hinge (not shown) at the bottom of the door 2, so that a user can pivot the door about the hinge in an upward or downward direction. An exhaust fan 9 formed in a predetermined location on the door 2 can forcefully expel air from inside the tub 18 to the outside. Also, a detergent cup 10 for holding a predetermined amount of detergent supplied therein is formed in the inner surface of the door 2, and supplies that amount of detergent during the operation of the dishwasher.

[45] Fig. 3 is a sectional view of the dishwasher in Fig. 1 taken along line I-I'.

[46] Referring to Fig. 3, a dishwasher according to the present invention further includes a water supply pipe 22 connecting the tub 18 and a water supply outside of the dishwasher to supply water into the tub 18, a water draining pipe 23 for draining wash liquid (that has been used for dishwashing and is contaminated), a steam generator 20 for generating steam and disposed below the tub 18, and a steam supply pipe 21 for supplying the steam generated by the steam generator 20 to the inside of the tub 18.

[47] In detail, the end of the steam supply pipe 21 in the tub 18 forms a steam discharger

26 for discharging steam therefrom at the bottom of the tub 18. The steam discharger 26 discharges steam from the bottom of the tub 18 upward. Thus, due to the rising characteristic of steam in air, the steam discharged from the steam supply pipe 21 can evenly permeate throughout the entire of the tub 18.

[48] A predetermined sealing member (not shown) seals the space between the outer perimeter of the end of the steam supply pipe 21 entering the tub 18 and the hole in the tub 18 through which the steam supply pipe 21 passes. In this way, wash liquid is prevented from leaking through the gap between the steam supply pipe 21 and the tub 18, and affecting interior components.

[49] The water supply pipe 22 branches in two. In order to regulate the flow of water passing through the branched water supply pipe 22, a tub water regulating valve 40 and a steam water regulating valve 41, for opening and closing the water supply pipe 22, are formed on the respective branches. The tub water regulating valve 40 controls the flow of water flowing to the tub, and the steam water regulating valve 41 controls the flow of water flowing to the steam generator 20.

[50] The operation of the above-described dishwasher according to the present invention will now be briefly described.

[51] In order to wash dishes, the door 2 is opened, and dishes are placed in the upper and lower dish racks 11 and 12, after which the door 2 is closed. Of course, before the door 2 is closed, a predetermined amount of detergent, rinse, etc. may be added to the detergent cup 10.

[52] By manipulating the controls 7, when a user inputs desired controls and begins the operation of the dishwasher, the display 8 displays the operating status of the dishwasher.

[53] When describing the operation of the dishwasher in terms of the flow sequence of wash liquid within the tub 18, wash liquid is first discharged from the upper and lower spray arms 14 and 15 and the top spray nozzle 24 to wash dishes in the upper and lower dish racks 11 and 12, after which the wash liquid descends to the sump 16 below. An impeller or other type of predetermined pump is installed in the sump 16, to pressurize and re-supply the wash liquid to the spray arms 14 and 15 and top spray nozzle 24. While the wash liquid circulates to the spray arms 14 and 15 and spray nozzle 24 from the sump 16, food residue is filtered by the filter 17 to prevent excessive contamination of the wash liquid and clogging of nozzles.

[54] At a certain point during the above operation of the dishwasher, the steam generated by the steam generator 20 passes through the steam supply pipe 21 to be supplied into the tub 18. Thus, the hot and moist characteristics of the steam ameliorate the operational reliability and efficiency of the dishwasher.

[55] Below, a controlling method, with respect to the operation of the steam generator 20 of a dishwasher according to the present invention, will be given in detail.

[56] Because steam is a gaseous form of boiled water that has hot and moist characteristics, it is suitable for improving washing efficiency of a dishwasher. Steam is especially suitable for soaking food residue dried and hardened on dishes for easy removal, and its heat is suitable for sterilizing purposes.

[57] Fig. 4 is a flowchart showing a controlling method of a dishwasher according to the first embodiment of the present invention.

[58] Referring to Fig. 4, before dishes are placed inside the dishwasher and the dishwasher is operated, water present in the dishwasher is first drained in an initial draining in step Sl.

[59] After the initial draining is completed, the steam generator 20 is operated and supplies steam into the tub 18 in step S2. The supplying of steam in step S2 is performed over a certain duration, and may be performed for a duration in which hardened food residue is adequately soaked. The steam may be supplied continuously into the tub 18 for at least a predetermined duration. The duration of supplying steam may be preset or automatically controlled. For example, when dirty dishes are put into the dishwasher after sitting for a long time, a user may enter a setting that supplies steam over a longer duration, so that the hardened food deposits have enough time to soften.

[60] After the food deposits are adequately soaked, in step S2 of supplying steam, wash liquid is supplied and sprayed toward the dishes by the lower and upper spray arms 14 and 15 and the top spray nozzle 24. The wash liquid sprayed through the spray arms and nozzle in step S3 may be sprayed at a lower pressure than normal and still easily remove food deposits that have already been softened by the steam. [61] After the dishes are washed to a certain extent of food deposits by the sprayed wash liquid, wash liquid supplied with detergent is sprayed to chemically remove grease from the dishes in step S4. This washing of dishes using wash water with detergent can be referred to as a main wash cycle, and the washing without using detergent can be referred to as a pre-wash cycle. [62] When the pre-wash and main wash cycles are completed, fresh wash liquid is supplied and sprayed to perform a rinse cycle in step S5. The rinse cycle may be repeated a number of times, depending on the condition of the dishes. [63] After the rinse cycle is completed, cool or hot air is forcibly blown to perform a drying cycle in step S6.

[64] When the drying cycle is completed, a cycle for storing dishes is performed.

[65] As described, the controlling method of a dishwasher according to the present invention performs a cycle of supplying steam to soak food residue before performing the wash cycle in which wash liquid is sprayed onto dishes. In this way, wash liquid sprayed at a lower pressure is more than adequate for washing dishes of food residue.

Because food residue can be washed using low pressure spray, the work performed by the pump to pressurize wash liquid can reduced. [66] Because food deposits are washed after being soaked, extra time is required to supply the steam; however, because the duration of spraying wash liquid is reduced, the entire course of the dishwasher consumes less time overall. [67] Food deposits that are hardened on dishes can be easily removed in this embodiment, so that the washing efficiency of dishes improves. [68] Also, because soaking is performed quickly, the dishwashing course takes less time, and the work performed by the pump is reduced, thereby saving energy.

Mode for the Invention [69] Alternative embodiments according to the present invention will be described below. Descriptions of like parts already described in the first embodiment shall be deemed included herein, and are therefore omitted herefrom. [70] Fig. 5 is a flowchart showing a controlling method of a dishwasher according to the second embodiment of the present invention. [71] Referring to Fig. 5, after dishes are stored inside the dishwasher, the operation of the dishwasher is begun. Prior to this, water already in the unit undergoes an initial draining in step SIl. After the initial draining has been performed, wash liquid is supplied and sprayed towards the dishes through the lower and upper spray arms 14 and 15 and the top spray nozzle 24. [72] During the spraying of wash liquid, larger food particles are washed in step S 12. This wash cycle, which is not supplied with detergent, washes food residue using only wash liquid, and can therefore be called a pre-wash cycle.

[73] After the pre- washing in step S 12 is completed, steam is supplied into the tub in step S 13. The supplying of steam in step S 13 is sustained for a predetermined duration, which may extend for a period suitable to completely soak the deposits hardened on the dishes. The steam is continuously consumed inside the tub 18, and may be supplied continuously for at least a predetermined duration. Also, the duration for supplying the steam may be preset or automatically determined. For example, when dirty dishes are put into the dishwasher after sitting for a long time, a user may enter a setting that supplies steam over a longer duration, so that the hardened food deposits have enough time to soften. This process may be referred to as a soaking steam supplying stage because the food deposits are soaked.

[74] The soaking steam supplying stage in step S13 soaks the food deposits, after which a main wash cycle is performed using wash liquid mixed with detergent in step S 14. The main wash cycle may be performed repeatedly several times depending on the state of the dishwasher operation.

[75] Even when the wash liquid that is sprayed through the spray arms and nozzle during the main wash cycle is sprayed at a lower pressure, it can easily clean the dishes because the dishes have already been soaked in the steam.

[76] After the main wash cycle is performed, a draining cycle of the wash liquid is performed in step S15, after which steam is supplied in step S16. Here, the hot steam that is supplied contacts the surfaces of the dishes and kills germs thereon, thus performing sterilizing.

[77] The steam supplied in step S 16 may be controlled, based on the quantity and types of dishes stored, and a user's direct input. For example, when items such as wash cloths and cutting boards that require a longer sterilizing time are being sterilized, a longer sterilizing setting may be inputted. Because hot steam is used for sterilizing in step S 16, this stage may be referred to as a sterilizing steam supplying stage.

[78] After the sterilizing steam supplying stage in step S 16 is performed, fresh wash liquid is supplied and sprayed to perform a rinse cycle in step S 17. The rinse cycle may be repeated several times, depending on the condition of the dishes.

[79] After the rinse cycle is completed, cool or hot air is blown to perform a drying cycle in step S 18.

[80] After the drying is completed, a storage cycle is performed.

[81] As described, the controlling method of a dishwasher according to the present invention supplies steam after the main wash cycle is completed, so that germs that may be present on the surfaces of dishes are killed, thereby increasing the level of sanitation of the dishes. In particular, steam is supplied in the stage before the rinsing cycle to perform sterilization, so that the removed germs can be discharged to the outside along with the wash liquid. Moreover, because steam is supplied again, the soaking of food residue is more efficient.

[82] In another embodiment, the soaking steam supplying in step S 13 and the sterilizing steam supplying in step S 16 may be selectively performed according to specific operating conditions, in order to prevent over supplying of steam and energy waste.

[83] In this embodiment, sterilizing efficiency is improved so that the sanitation of dishes increases.

[84] Fig. 6 is a flowchart showing a controlling method of a dishwasher according to the third embodiment of the present invention.

[85] Referring to Fig. 6, dishes are stored within the dishwasher, after which the dishwasher is activated. Prior to this, water already in the unit undergoes an initial draining in step S21. After the initial draining has been performed, wash liquid is supplied and sprayed towards the dishes through the lower and upper spray arms 14 and 15 and the top spray nozzle 24.

[86] During the spraying of wash liquid, larger food particles are washed in step S22.

This wash cycle, which is not supplied with detergent, washes food residue using only wash liquid, and can therefore be called a pre-wash cycle.

[87] After the pre- washing in step S22 is completed, steam is supplied into the tub 18 in step S33. The supplying of steam in step S23 is sustained for a predetermined duration, which may extend for a period suitable to completely soak the deposits hardened on the dishes. The steam is continuously consumed inside the tub 18, and may be supplied continuously for at least a predetermined duration. Also, the duration for supplying the steam may be preset or automatically determined. For example, when dirty dishes are put into the dishwasher after sitting for a long time, a user may enter a setting that supplies steam over a longer duration, so that the hardened food deposits have enough time to soften.

[88] The soaking steam supplying stage in step S23 soaks the food deposits, after which a determining of whether to repeatedly perform the spraying of wash liquid in step S22 and the supplying of steam in step S23, based on the turbidity of the wash liquid and/or the stage of the wash course and/or a user's direct input, is performed in step S24.

[89] If it is determined in step S24 that previous steps should be repeated, the spraying of wash liquid in step S22 and the supplying of steam in step S23 is repeatedly performed. Of course, after steps S22 and S23 are both repeated once, step S24 is again performed to determine whether to repeat the steps again. Furthermore, by adding detergent to the sprayed wash liquid in at least one of the repetitions of step S22 during the repeated performing of steps S22 and S23, the wash liquid may be sprayed with detergent mixed therein, so that it can completely clean grease from the dishes. Also, the wash liquid may be drained at a point during the repeating cycles, according to the condition of the wash liquid.

[90] The number of repeated cycles may be varied according to relevant conditions. For example, if glutinous rice should be hardened and stuck firmly on the dishes, requiring a vigorous wash cycle, a plurality of spraying cycles of wash liquid may be implemented without using detergent.

[91] Additionally, when it is determined in step S24 that the repeated cycles are no longer needed, steam is again supplied in step S25 to completely sterilize the dishes. Fresh rinse water is sprayed on the dishes in a rinse cycle in step S26, and cool or hot air is supplied in step S27 in for drying. The repeated supplying of steam in step S25 may selectively be performed as required.

[92] The steam supplied by the controlling method of a dishwasher according to the present invention may be varied, based on the quantity and types of dishes stored, and a user's direct input. For example, when items such as wash cloths and cutting boards that require a longer sterilizing time are being sterilized, a longer sterilizing setting may be inputted. It also follows that the larger the quantity of dishes, the longer the sterilizing may be performed.

[93] As described, the controlling method of a dishwasher according to the present invention continuously supplies steam after the spraying of wash liquid is completed (in other words, the supplying of steam is alternately performed with the spraying of wash liquid), thereby increasing the level of sanitation of the dishes. That is to say, the supplying of steam soaks food residue to increase the cleanliness of the dishes from a physical standpoint. In the stage prior to the rinse cycle in step S26, steam is supplied once more to further sterilize the dishes.

[94] Fig. 7 is flowchart showing a controlling method of a dishwasher according to the fourth embodiment of the present invention.

[95] Referring to Fig. 7, dishes are stored within the dishwasher, after which the dishwasher is activated. Prior to this, water already in the unit undergoes an initial draining in step S31. After the initial draining has been performed, wash liquid is supplied and sprayed towards the dishes through the lower and upper spray arms 14 and 15 and the top spray nozzle 24.

[96] During the spraying of wash liquid, larger food particles are washed in step S32.

[97] After the pre- washing in step S32 is completed, steam is supplied into the tub 18 in step S33. The supplying of steam in step S33 is performed by supplying the steam generated by the steam generator 20 through the steam supply pipe 21 into the tub 18. The supplying of steam in step S33 is sustained for a predetermined duration, which may extend variably, depending on the quantity and state of cleanliness of dishes stored in the tub 18. For example, a setting that supplies steam over a longer duration may be used for glutinous rice that is hardened and stuck on dishes.

[98] After the supplying of steam in step S33, fresh wash liquid with detergent mixed therein is supplied and sprayed into the tub 18 in a main wash cycle in step S34.

[99] After the supplying of steam in step S33 and the spraying of wash liquid in step S 34 soaks food deposits to a certain degree, it is determined in step S35 whether to repeat steps S34 and S33, according to the wash course settings and/or a user's inputs. Thus, the repeated number of times that wash liquid is sprayed in step S 34 and steam is supplied in step S33 is compared to a preset number, and if the numbers are unequal, the steps S 34 and S33 are repeated.

[100] Because the time that food residue soaks lengthens as the number of spraying repetitions of wash liquid increases in the main wash cycle, the amount of food residue remaining on dishes decreases. Moreover, because food deposits hardened on dishes are softened during the supplying of steam in step S33, the food deposits can be completely removed.

[101] By alternating and repeating the spraying of wash liquid in step S 34 and the supplying of steam in S33, food residue can be more reliably removed, thereby increasing the cleaning efficiency of dishes.

[102] After the main wash cycle is completed, the wash liquid is drained in step S36, a rinse cycle is performed in step S37 using clean water, and a drying cycle is performed in step S38 using cool or hot blown air.

[103] The steam supplied by the controlling method of a dishwasher according to the present invention may be varied, based on the quantity and types of dishes stored, and a user's direct input. For example, the larger the quantity of dishes, the more steam should be supplied.

[104] As described, the controlling method of a dishwasher according to the present invention continuously sprays wash liquid and supplies steam in the main wash cycle. That is to say, the supplying of steam soaks food residue to increase the cleanliness of the dishes from a physical standpoint. Furthermore, because the wash liquid spraying and steam supplying are alternatingly repeated, the dishes are cleaned that much more efficiently.

[105] Fig. 8 is flowchart showing a controlling method of a dishwasher according to the fifth embodiment of the present invention.

[106] Referring to Fig. 8, dishes are stored within the dishwasher, after which the dishwasher is activated. Prior to this, water already in the unit undergoes an initial draining in step S41. After the initial draining has been performed, steam is supplied into the tub 18 in step S42. The supplying of steam in step S42 is performed by supplying the steam generated by the steam generator 20 through the steam supply pipe 21 into the tub 18. The supplying of steam in step S42 is sustained for a predetermined duration, which may extend variably, depending on the quantity and state of cleanliness of dishes stored in the tub 18. For example, a setting that supplies steam over a longer duration may be used for glutinous rice that is hardened and stuck on dishes.

[107] After the steam is supplied over a certain duration, wash liquid is supplied and sprayed towards the dishes through the lower and upper spray arms 14 and 15 and the top spray nozzle 24. During the spraying of wash liquid, larger food particles are washed in step S43. This wash cycle, which is not supplied with detergent, washes food residue using only wash liquid, and can therefore be called a pre-wash cycle.

[108] After a one-time supplying of steam in step S42 that soaks food deposits to a certain degree and the spraying of wash liquid in step S43, it is determined in step S44 whether to repeat steps S43 and S42, according to the wash course settings and/or a user's inputs. The number of times the spraying of wash liquid in step S43 and the supplying of steam in S42 are repeated is compared to a preset number, and if the numbers are unequal, the steps S43 and S42 are repeated.

[109] Because the time that food residue soaks lengthens as the number of spraying repetitions of wash liquid increases in the main wash cycle, the amount of food residue remaining on dishes decreases. Moreover, because food deposits hardened on dishes are softened during the supplying of steam in step S42, the food deposits can be completely removed.

[110] By alternating and repeating the spraying of wash liquid in step S43 and the supplying of steam in step S42, food residue can be more reliably removed, thereby increasing the cleaning efficiency of dishes.

[Ill] Next, when the preset number equals the number of repetitions, the pre-wash cycle ends, and wash liquid with detergent mixed therein is sprayed in the main wash cycle in step S45. After the main wash cycle is completed, fresh rinsing water is sprayed on the dishes in a rinse cycle in step S46, and then a drying cycle is implemented in step S47 using cool or hot blown air.

[112] The steam supplied by the controlling method of a dishwasher according to the present invention may be varied, based on the quantity and types of dishes stored, and a user's direct input. For example, the larger the quantity of dishes, the more steam should be supplied.

[113] As described, the controlling method of a dishwasher according to the present invention supplies steam in a prewash cycle and sprays wash liquid, alternating the two steps. That is to say, because the wash liquid spraying and steam supplying are al- ternatingly repeated, the dishes are cleaned that much more efficiently. [114] That is to say, the supplying of steam soaks food residue to increase the cleanliness of the dishes from a physical standpoint. Furthermore, because the wash liquid spraying and steam supplying are alternatingly repeated, the dishes are cleaned that much more efficiently.

[115] Fig. 9 is flowchart showing a controlling method of a dishwasher according to the sixth embodiment of the present invention.

[116] Referring to Fig. 9, dishes are stored within the dishwasher, after which the dishwasher is activated. Prior to this, water already in the unit undergoes an initial draining in step S51. After the initial draining has been performed, steam is supplied into the tub 18 in step S52. The supplying of steam in step S52 is performed by supplying the steam generated by the steam generator 20 through the steam supply pipe 21 into the tub 18. The supplying of steam in step S52 is sustained for a predetermined duration, which may extend variably, depending on the quantity and state of cleanliness of dishes stored in the tub 18. For example, a setting that supplies steam over a longer duration may be used for glutinous rice that is hardened and stuck on dishes.

[117] After the steam is supplied over a certain duration in step S52, wash liquid is sprayed in step S53 towards the dishes. Even when the wash liquid is sprayed at a lower pressure, it can easily remove food residue that has already been soaked by the steam.

[118] After a one-time supplying of steam in step S52 and a spraying of wash liquid in step S53, it is determined in step S54 whether to repeat steps S53 and S52, according to the wash course settings and/or a user's inputs. The number of times the spraying of wash liquid in step S53 and the supplying of steam in S52 are repeated is compared to a preset number, and if the numbers are unequal, steps S53 and S52 are repeated.

[119] Because the time that food residue soaks lengthens as the number of spraying repetitions of wash liquid increases in the main wash cycle, the amount of food residue remaining on dishes decreases. Moreover, because food deposits hardened on dishes are softened during the supplying of steam in step S52, the food deposits can be completely removed.

[120] By alternating and repeating the spraying of wash liquid in step S53 and the supplying of steam in S52, food residue can be more reliably removed, thereby increasing the cleaning efficiency of dishes.

[121] Furthermore, by adding detergent to the sprayed wash liquid in at least one of the repetitions of step S53 during the repeated performing of steps S52 and S53, the wash liquid may be sprayed with detergent mixed therein, so that it can completely clean grease from the dishes.

[122] At least one rinse cycle without using detergent may be performed during the repeating wash liquid spraying in step S53 and the supplying of steam in step S52 as a final rinsing cycle, in order to prevent detergent from remaining on dishes.

[123] After the number of repetitions is determined to be equal to a preset number and the spraying of the wash liquid is ended, cool or hot air is supplied in a drying cycle in step S55.

[124] The steam supplied by the controlling method of a dishwasher according to the present invention may be varied, based on the quantity and types of dishes stored, and a user's direct input. For example, the larger the quantity of dishes, the more steam should be supplied.

[125] As described, the controlling method of a dishwasher according to the present invention supplies steam to soak food residue and sprays wash liquid, alternating the two steps. That is to say, because the wash liquid spraying and steam supplying are al- ternatingly repeated, the dishes are cleaned that much more efficiently. In other words, the supplying of steam soaks food residue to allow easy washing of the residue from dishes, and sterilizes germs on the surfaces of dishes through the hot steam.

[126] The supplying of steam soaks food deposits and increase the cleanliness of the dishes from a physical standpoint. Furthermore, because the wash liquid spraying and steam supplying are alternatingly repeated, the dishes are cleaned that much more efficiently.

[127] Also, because hot steam can be discharged in multiple cycles, the sterilizing effect of dishes is ameliorated.

[128] Fig. 10 is flowchart showing a controlling method of a dishwasher according to the seventh embodiment of the present invention.

[129] Referring to Fig. 10, dishes are stored within the dishwasher, after which the dishwasher is activated. Prior to this, water already in the unit undergoes an initial draining in step S61.

[130] After the initial draining has been performed, a pre-wash cycle is performed in step

S62. The pre-wash cycle in step S62 is a cycle that uses water without detergent mixed in to wash comparatively large food particles from dishes.

[131] After the pre-wash cycle is ended, the wash liquid is drained, and fresh wash liquid is supplied and mixed with detergent in step S63. The detergent is sprayed with the wash liquid onto the dishes, and steam is supplied to activate the detergent in step S64. Steam is supplied into the tub 18 and contacts the detergent, activating the detergent. The amount of steam supplied to the tub 18 may be adjusted depending on the cleanliness of dishes and other factors. For example, in the case of dishes with lots of grease on their surfaces, the duration of supplying steam may be extended. Needless to say, the steam may be supplied in the tub for a preset duration.

[132] When the steam is supplied over a predetermined duration, the detergent is activated, and wash liquid is sprayed in step S66, eliminating impurities. Here, because the detergent has been activated, the dishes can be cleaned more thoroughly.

[133] After the pre-wash cycle and the main wash cycle are completed, the wash liquid is drained in step S67, and fresh wash liquid is supplied and sprayed to perform a rinse cycle in step S68. The rinse cycle may be performed a plurality of times, depending on the state of the dishes.

[134] When the rinse cycle is ended, cool or hot air is forcibly blown to perform a drying cycle in step S69.

[135] When the drying cycle ends, a storing cycle of the dishes is implemented.

[136] As described, the controlling method of a dishwasher according to the present invention discharges steam into the tub 18 over a predetermined duration after detergent is sprayed on dishes. Because the steam activates the detergent on the dishes, the dishwashing efficiency increases.

[137] Because soaking of food deposits can be performed by supplying steam, even when the wash liquid is sprayed at a lower pressure, it suffices for washing deposits off the dishes. Because wash liquid sprayed at a lower pressure is able to remove food deposits, the pump pressurizing the wash liquid does not have to perform as much work.

[138] Because washing is performed after food residue is soaked, the process of supplying steam takes more time; however, due to the time of spraying wash liquid being shortened as a result, the overall duration of a wash course can be shortened.

[139] Also, the hot steam acts to sterilize dishes.

[140] A further embodiment according to the present invention does not spray wash liquid with detergent before supplying steam, but supplies steam for a predetermined period first in order to activate the detergent. The important factor is how long steam is supplied after detergent is deposited on the dishes.

[141] While the present invention has been described and illustrated herein with reference to the preferred embodiments thereof, it will be apparent to those skilled in the art that various modifications and variations can be made therein without departing from the spirit and scope of the invention. Thus, it is intended that the present invention covers the modifications and variations of this invention that come within the scope of the appended claims and their equivalents. Industrial Applicability

[142] The dishwasher and the controlling method thereof according to the present invention improve dishwashing efficiency, reduce energy consumption, and improve sanitation of dishes, for a high industrial applicability.

[143]

Claims

[ 1 ] A dishwasher comprising : a tub for storing dishes; a steam generator for generating steam to be supplied into the tub; and a connecting passage for connecting a discharging end of the steam generator to an inside of the tub.

[2] The dishwasher according to claim 1, wherein an end of the connecting passage connected to the inside of the tub is formed at a bottom portion of the tub.

[3] The dishwasher according to claim 1, wherein an end portion of the connecting passage connected to the inside of the tub is sealed against the tub.

[4] The dishwasher according to claim 1, wherein the connecting passage discharges steam from a bottom to a top of the tub.

[5] The dishwasher according to claim 1, wherein the steam soaks impurities deposited on the dishes.

[6] The dishwasher according to claim 5, wherein the steam performs a soaking of impurities on the dishes, after which wash liquid is sprayed on the dishes to wash the dishes.

[7] The dishwasher according to claim 1, wherein the steam generator supplies the steam in at least one of a cycle before and after a main cycle in which wash liquid mixed with detergent is sprayed onto the dishes.

[8] The dishwasher according to claim 1, wherein the steam generator supplies steam into the tub at least two times with a predetermined interval therebetween.

[9] The dishwasher according to claim 1, wherein the dishwasher performs a main wash cycle that alternately implements a steam supplying cycle for supplying steam into the tub and a wash liquid spraying cycle for spraying wash liquid mixed with detergent onto the dishes.

[10] The dishwasher according to claim 9, wherein the main wash cycle is repeated a plurality of times.

[11] The dishwasher according to claim 1, wherein the dishwasher performs a pre- wash cycle that alternately implements a steam supplying cycle for supplying steam into the tub and a wash liquid spraying cycle for spraying wash liquid that is not mixed with detergent onto the dishes.

[12] The dishwasher according to claim 11, wherein the pre-wash cycle is repeated a plurality of times.

[13] The dishwasher according to claim 1, wherein the dishwasher alternately performs a steam supplying cycle for supplying the steam into the tub and a wash liquid spraying cycle for spraying wash liquid onto the dishes.

[14] The dishwasher according to claim 1, wherein the steam generator supplies steam into the tub for a predetermined duration when wash liquid mixed with detergent is deposited on the dishes.

[15] A controlling method of a dishwasher, comprising: preparing a dishwasher including a tub for storing dishes, a steam generator for generating steam to be supplied into the tub, and a connecting passage for connecting a discharging end of the steam generator to an inside of the tub; supplying steam into the tub from the steam generator; and spraying wash liquid onto the dishes.

[16] The controlling method according to claim 15, wherein the supplying of the steam into the tub is performed for soaking impurities deposited on the dishes, after which the spraying of the wash liquid onto the dishes is performed.

[17] The controlling method according to claim 16, wherein the spraying of the wash liquid includes spraying wash liquid that is not mixed with detergent and spraying wash liquid that is mixed with detergent.

[18] The controlling method according to claim 17, wherein the spraying of the wash liquid that does include the detergent is performed after the spraying of the wash liquid that does not include the detergent.

[19] The controlling method according to claim 15, further comprising drying of the dishes after the the supplying of the steam and the spraying of the wash liquid.

[20] The controlling method according to claim 15, wherein the supplying of the steam into the tub fills the tub with the steam when the dishes are deposited with detergent through the spraying of the wash liquid.

[21] The controlling method according to claim 20, wherein the filling of the tub with the steam continues over a predetermined duration.

[22] The controlling method according to claim 20, further comprising a further spraying of wash liquid after the filling of the tub with the steam.

[23] The controlling method according to claim 15, wherein the steam supplied in the supplying of the steam is quantitively variable.

[24] A controlling method of a dishwasher, comprising: preparing a dishwasher including a tub for storing dishes, a steam generator for generating steam to be supplied into the tub, and a connecting passage for connecting a discharging end of the steam generator to an inside of the tub; supplying steam into the tub from the steam generator; spraying wash liquid onto the dishes; spraying the wash liquid again and determining whether to repeat the supplying of the steam; and alternately repeating the spraying of the wash liquid and the supplying of the steam when the determining determines to repeat the supplying of the steam.

[25] The controlling method according to claim 24, wherein the alternating repeating of the spraying of the wash liquid and the supplying of the steam is continued.

[26] The controlling method according to claim 24, wherein the supplying of the steam is implemented a final time, when the determining determines not to repeat the supplying of the steam.

[27] The controlling method according to claim 24, wherein the determining of whether to repeat the supplying of the steam is based on at least one of a turbidity of the wash liquid, a wash course status, and a selection of a user.

[28] The controlling method according to claim 24, wherein the spraying of the wash liquid includes a spraying of wash liquid that is not mixed with detergent and a spraying of wash liquid that is mixed with detergent.

[29] The controlling method according to claim 24, wherein the spraying of the wash liquid is performed after the supplying of the steam into the tub and impurities on the dishes have been soaked.

[30] A controlling method of a dishwasher, comprising: preparing a dishwasher including a tub for storing dishes, a steam generator for generating steam to be supplied into the tub, and a connecting passage for connecting a discharging end of the steam generator to an inside of the tub; performing a main wash cycle through spraying wash liquid mixed with detergent for washing the dishes; and supplying the steam from the steam generator into the tub in at least one of a cycle before and after the main wash cycle.

[31] The controlling method according to claim 30, wherein the supplying of the steam is performed in the cycle before the main wash cycle, for soaking impurities deposited on the dishes.

[32] The controlling method according to claim 30, wherein the supplying of the steam is performed in the cycle after the main wash cycle, for sterilizing the dishes.

[33] The controlling method according to claim 30, further comprising a pre-wash cycle including supplying the steam into the tub for soaking food deposits on the dishes, and spraying wash liquid that is not mixed with detergent onto the dishes, the pre-wash cycle performed before the main wash cycle.

[34] The controlling method according to claim 33, wherein the pre-wash cycle alternately performs the supplying of the steam and the spraying of the wash liquid. [35] The controlling method according to claim 34, wherein the pre-wash cycle is repeated until a number of repetitions thereof reaches a predetermined set number. [36] The controlling method according to claim 30, wherein the main wash cycle includes supplying the steam into the tub. [37] The controlling method according to claim 30, wherein the main wash cycle is repeated until a number of repetitions thereof reaches a predetermined set number. [38] The controlling method according to claim 30, further comprising rinsing the dishes after a final stage of the main wash cycle.