Title:
Dish washer and method of controlling the same
Kind Code:
A1


Abstract:
Disclosed are a dish washer and a method of controlling the same, in which the amount of water consumed is reduced and a washing time is maintained while assuring a washing performance. The dish washer includes a washing tub; dish baskets provided in the washing tub to accommodate dishes; and a plurality of nozzles to spray washing water to the dish baskets, where spray holes to spray the washing water are formed through each of the plurality of nozzles, and the spray holes formed through the plurality of nozzles have areas different from one another.



Inventors:
Kennichi, Shimotera (Seoul, KR)
Kwon, Young Ho (Seongnam-si, KR)
Ryu, Jung Chan (Suwon-si, KR)
Application Number:
12/007124
Publication Date:
10/02/2008
Filing Date:
01/07/2008
Assignee:
Samsung Electronics Co., Ltd. (Suwon-si, KR)
Primary Class:
Other Classes:
134/18, 134/57D, 134/199
International Classes:
A47L15/16; A47L15/46
View Patent Images:
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Primary Examiner:
KO, JASON Y
Attorney, Agent or Firm:
STAAS & HALSEY LLP (WASHINGTON, DC, US)
Claims:
What is claimed is:

1. A dish washer, comprising: a washing tub; dish baskets provided in the washing tub to accommodate dishes; and a plurality of nozzles spraying washing water to the dish baskets, each of the nozzles having spray holes spraying the washing water formed through each of the nozzles, the spray holes being sized differently from one another for each of the nozzles.

2. The dish washer according to claim 1, wherein: the plurality of nozzles includes upper and lower nozzles installed above and below the dish baskets and a middle nozzle installed between the dish baskets; and the spray holes formed through the middle nozzle have an area larger than an area of the spray holes formed through the lower nozzle so that an amount of the washing water sprayed from the middle nozzle is larger than an amount of the washing water sprayed from the lower nozzle.

3. The dish washer according to claim 2, wherein the middle nozzle has a first set of spray holes to spray the washing water upwardly from the middle nozzle and a second set of spray holes to spray the washing water downwardly from the middle nozzle formed there through.

4. The dish washer according to claim 2, further comprising a control unit to control a flow of the washing water supplied to the upper, middle, and lower nozzles, the control unit setting an amount of the washing water in at least one mode out of a plurality of modes of washing the dishes with the washing water to be smaller than an amount of the washing water in other modes of the plurality of modes.

5. The dish washer according to claim 4, wherein the at least one mode is a preliminary washing mode or a preliminary rinsing mode.

6. The dish washer according to claim 5, further comprising a circulation pump to circulate the washing water in the washing tub to guide the washing water to the upper, middle, and lower nozzles, wherein the control unit controls the upper and middle nozzles to spray the washing water by an operation of the circulation pump in the preliminary washing mode or the preliminary rinsing mode.

7. A method of controlling a dish washer having a washing tub, dish baskets provided in the washing tub to accommodate dishes, a plurality of nozzles to spray washing water to the dish baskets, and a heater to heat the washing water, the method comprising: supplying an amount of the washing water in at least one mode out of a plurality of modes of washing the dishes with the washing water less than an amount of the washing water supplied in other modes of the plurality of modes.

8. The method according to claim 7, wherein the at least one mode is a mode in which the heater is not operated.

9. The method according to claim 8, wherein the mode in which the heater is not operated is a preliminary washing mode or a preliminary rinsing mode.

10. The method according to claim 7, wherein the supply of the washing water is controlled such that a level of the washing water in the washing tub is sensed, and when the sensed level is less than a predetermined low water level during an operation of the heater, the washing water is supplied to the washing tub.

11. The dish washer according to claim 2, wherein a nozzle area ratio of the middle nozzle to the lower nozzle is 1.5 to 1.

12. A method of controlling a dish washer having upper, middle and lower nozzles and a heater, comprising: supplying washing water only through the upper and middle nozzles in a mode in which the heater is not operated, an amount of the water supplied through the middle nozzle being greater than an amount of the water supplied through the upper and lower nozzles.

13. The method according to claim 12, wherein the washing water is supplied through only the upper and middle nozzles in a preliminary washing mode or a preliminary rinsing mode, the preliminary washing mode and the preliminary rinsing modes being modes prior to a main washing mode and a main rinsing mode, respectively.

14. A dishwasher, comprising: a plurality of nozzles including at least a middle nozzle, the middle nozzle being provided at a middle portion of the dishwasher, the middle nozzle having a water supplying capacity greater than that of a water supplying capacity of other nozzles of the plurality of nozzles.

15. The dishwasher according to claim 14, wherein the middle nozzle has a plurality of spray holes formed there through having a larger area than an area of a plurality of spray holes formed through the other nozzles.

16. The dishwasher according to claim 14, wherein the plurality of nozzles includes an upper nozzle provided at an upper portion of the dishwasher, the middle nozzle supplying the water only with the upper nozzle in a preliminary washing mode or a preliminary rinsing mode, the preliminary washing and rinsing modes being modes prior to a main washing mode and a main rinsing mode, respectively.

17. A method of controlling a dishwasher having upper, middle and lower nozzles and a heater, the method comprising: supplying water through only the upper and middle nozzles in a preliminary washing mode or a preliminary rinsing mode, the preliminary washing and rinsing modes being modes prior to a main washing mode and a main rinsing mode, respectively; and supplying water through all of the upper, middle and lower nozzles in the main washing mode and a main rinsing mode.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 2007-0030566, filed Mar. 28, 2007, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

1. Field

The present invention relates to a dish washer and a method of controlling the same, and more particularly, to a dish washer and a method of controlling the same, in which the amount of water consumed is reduced while assuring a washing performance.

2. Description of the Related Art

Generally, dish washers are apparatuses that wash out contaminants (i.e., food waste, etc.) stuck to dishes by spraying cold or warm washing water at a high pressure onto the dishes. Korean Patent Laid-open Publication No. 10-2005-0105721 discloses a dish washer.

The dish washer disclosed in the above Publication includes a washing tub to wash dishes supplied thereinto, a plurality of dish baskets provided in multiple stages in the washing tub to receive the dishes, spray nozzles provided above and below the plurality of dish baskets to spray washing water, and a sump connected to the spray nozzles to pump the washing water to the spray nozzles.

In the above dish washer, when washing water is supplied to an inside of the washing tub under the condition that dishes to be washed are put in the dish baskets, a circulation pump in the sump is operated to supply the washing water to the spray nozzles, thus washing the dishes by the high injection pressure of the washing water. This washing process, including washing and rinsing steps, is divided into main modes, including a main washing mode and a last rinsing mode, and preliminary modes, including a preliminary washing mode and a preliminary rinsing mode, and the modes are repeated four to six times according to courses. The temperature of the washing water and the time of each of the modes are determined according to the courses.

In the dish washer, an amount of the washing water required to operate the circulation pump, which is needed by the spray nozzles, is supplied in each of the modes. In the case that the amount of the washing water required in each of the modes is 5 L, as the total number of the main modes and the preliminary modes in a standard course is four, thus 20 L of the washing water is required. A criterion to calculate the energy required in the dish washer is the sum of the electric energy consumed by electric field products, such as the circulation pump, a heater, etc., during the course and the heat energy of temperature conversion efficiency in proportion to the amount of the washing water consumed. Accordingly, in order to reduce the energy, it is important to reduce the amount of the washing water consumed.

In order to reduce the amount of the washing water consumed for the purpose of energy saving, a method in which a small-sized circulation pump and the number of spray holes of spray nozzles are reduced was proposed. However, this method has several problems, such as the deterioration of the washing performance of the dish washer due to the increase of a portion of the inside of a dish washer, to which the washing water is not sprayed, and the increase in washing time to obtain a desired washing performance of the dish washer.

SUMMARY

Therefore, one aspect of the embodiment is to provide a dish washer and a method of controlling the same, in which the amount of water consumed is reduced and a washing time is maintained while assuring a washing performance.

Another aspect of the embodiment is to provide a dish washer and a method of controlling the same, in which an area ratio of spray holes of upper, middle, and lower nozzles is converted such that the amount of water sprayed from the middle nozzle is maximized, so as to increase a washing performance.

Yet another aspect of the embodiment is to provide a dish washer and a method of controlling the same, in which the amount of water consumed in preliminary modes carried out prior to main modes is decreased, to decrease the amount of water required in the entirety of the modes.

Additional aspects and/or advantages will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.

The foregoing and/or other aspects are achieved by providing a dish washer including a washing tub; dish baskets provided in the washing tub to accommodate dishes; and a plurality of nozzles to spray washing water to the dish baskets, each of the nozzles having spray holes to spray the washing water formed through each of the nozzles, the spray holes formed through the plurality of nozzles being size differently from one another and thus having areas different from one another for each of the nozzles.

The plurality of nozzles may include upper and lower nozzles installed above and below the dish baskets and a middle nozzle installed between the dish baskets, and the spray holes formed through the middle nozzle may have an area larger than an area of the spray holes formed through the lower nozzle so that an amount of the washing water sprayed from the middle nozzle is larger than an amount of the washing water sprayed from the lower nozzle.

The middle nozzle may have a first set of spray holes to spray the washing water upwardly from the middle nozzle and a second set of spray holes to spray the washing water downwardly from the middle nozzle formed there through.

The dish washer may further include a control unit to control a flow of the washing water supplied to the upper, middle, and lower nozzles, the control unit setting an amount of the washing water in at least one mode out of a plurality of modes of washing the dishes with the washing water to be smaller than an amount of the washing water in other modes of the plurality of modes.

The at least one mode may be a preliminary washing mode or a preliminary rinsing mode.

The dish washer may further include a circulation pump to circulate the washing water in the washing tub to guide the washing water to the upper, middle, and lower nozzles, and the control unit may control the upper and middle nozzles to spray the washing water by an operation of the circulation pump in the preliminary washing mode or the preliminary rinsing mode.

A nozzle area ratio of the middle nozzle to the lower nozzle is 1.5 to 1.

The foregoing and/or other aspects are achieved by providing a method of controlling a dish washer having a washing tub, dish baskets provided in the washing tub to accommodate dishes, a plurality of nozzles to spray washing water to the dish baskets, and a heater to heat the washing water, the method including supplying an amount of the washing water in at least one mode out of a plurality of modes of washing the dishes with the washing water less than an amount of the washing water supplied in other modes of the plurality of modes.

The at least one mode may be a mode in which the heater is not operated.

The mode in which the heater is not operated may be a preliminary washing mode or a preliminary rinsing mode.

The supply of the washing water may be controlled such that a level of the washing water in the washing tub is sensed, and when the sensed level is less than a predetermined low water level during an operation of the heater, the washing water is supplied to the washing tub.

The foregoing and/or other aspects are achieved by providing a method of controlling a dish washer having upper, middle and lower nozzles and a heater, including supplying washing water only through the upper and middle nozzles in a modes in which the heater is not operated, an amount of the water supplied through the middle nozzle being greater than an amount of the water supplied through the upper and lower nozzles.

The washing water may be supplied through only the upper and middle nozzles in a preliminary washing mode or a preliminary rinsing mode, the preliminary washing mode and the preliminary rinsing modes being modes prior to a main washing mode and a main rinsing mode, respectively.

The foregoing and/or other aspects are achieved by providing a dishwasher, including: a plurality of nozzles including at least a middle nozzle, the middle nozzle being provided at a middle portion of the dishwasher, the middle nozzle having a water supplying capacity greater than that of a water supplying capacity of other nozzles of the plurality of nozzles.

The middle nozzle may have a plurality of spray holes formed there through having a larger area than an area of a plurality of spray holes formed through the other nozzles.

The plurality of nozzles may include an upper nozzle provided at an upper portion of the dishwasher, the middle nozzle supplying the water only with the upper nozzle in a preliminary washing mode or a preliminary rinsing mode, the preliminary washing and rinsing modes being modes prior to a main washing mode and a main rinsing mode, respectively.

The foregoing and/or other aspects are achieved by providing a method of controlling a dishwasher having upper, middle and lower nozzles and a heater, the method including: supplying water through only the upper and middle nozzles in a preliminary washing mode or a preliminary rinsing mode, the preliminary washing and rinsing modes being modes prior to a main washing mode and a main rinsing mode, respectively; and supplying water through all of the upper, middle and lower nozzles in the main washing mode and a main rinsing mode.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a longitudinal sectional view of a dish washer in accordance with the present embodiment;

FIG. 2 is a control block diagram of a dish washer in accordance with an embodiment; and

FIGS. 3A to 3C are flow charts to illustrate a method of controlling a dish washer in accordance with the present embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the embodiment, an example of which is illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiment is described below to explain the present invention by referring to the annexed drawings.

FIG. 1 is a longitudinal sectional view of a dish washer in accordance with the present embodiment.

In FIG. 1, the dish washer of the present embodiment includes a main body 10 having a washing space formed therein, and a door 12 to open and close the front surface of the main body 10. The main body 10 and the door 12 form the external appearance of the dish washer.

A washing tub 20 is provided in the main body 10. In the washing tub 20, upper and lower dish baskets 22a and 22b to accommodate dishes, racks 24a and 24b slidably supporting the upper and lower dish baskets 22a and 22b, and upper, middle, and lower spray nozzles 26a, 26b, and 26c located above and below the dish baskets 22a and 22b to spray washing water are provided.

The upper and middle spray nozzles 26a and 26b are connected to a sump 42, which will be described later, by a first supply pipe 28a, and the lower spray nozzle 26c is connected to the sump 42 by the second supply pipe 28b. Thereby, the washing water is supplied from the sump 42 to the upper, middle, and lower spray nozzles 26a, 26b, and 26c.

Here, the washing water supplied to the upper and middle spray nozzles 26a and 26b through the first supply pipe 28a and the washing water supplied to the lower spray nozzle 26c through the second supply pipe 28b are independently sprayed by an operation of the upper and middle spray nozzles 26a and 26b and an operation of the lower spray nozzle 26c. For this reason, a separated water flow converting device is provided, or valves are respectively provided in the first and second supply pipes 28a and 28b.

The upper, middle, and lower spray nozzles 26a, 26b, and 26c are designed such that the area ratio of spray holes of the upper, middle, and lower spray nozzles 26a, 26b, and 26c to inject the washing water is set to 0.5:1.5:1, for example, to maximize an amount of the washing water sprayed from the middle spray nozzle 26b. That is, the amount of the washing water sprayed from the middle spray nozzle 26b is larger than the amount of the washing water sprayed from the lower spray nozzle 26c, and thus it is possible to sufficiently carry out the preliminary washing and preliminary rinsing of dishes accommodated in the lower dish basket 22b with the washing water sprayed downwardly from the middle spray nozzle 26b and the falling water.

The middle spray nozzle 26b is provided with a plurality of spray holes to upwardly spray the washing water and a plurality of spray holes to downwardly spray the washing water, thereby simultaneously spraying the washing water upwardly and downwardly.

A heater 30 to heat the washing water is provided on the bottom of the washing tub 20. The heater 30 is seated in a heater mounting groove 32 formed in the bottom of the washing tub 20.

A machinery chamber 40 is prepared under the washing tub 20. The sump 42, which collects and pumps the washing water supplied to the inside of the washing tub 20 to transfer the washing water to the upper, middle, and lower spray nozzles 26a, 26b, and 26c, is provided in the machinery chamber 40, and a temperature sensor 44 to sense the temperature of the washing water is installed in the sump 42.

Various channels and a circulation pump 46 to pump the washing water to the channels are provided in the sump 42, and a drain pump 48 to drain the contaminated washing water to the outside through a drain pipe 52 and a drain valve 50 are provided at one side of the sump 42.

FIG. 2 is a control block diagram of a dish washer in accordance with an embodiment. In addition to the components, which are shown in FIG. 1, the dish washer further includes a water level sensing unit 58, an input unit 60, a control unit 62, a driving unit 64, and a display unit 68.

The water level sensing unit 58 senses the amount (level) of water (washing water) supplied to the washing tub 20. The input unit 60 inputs various washing courses (for example, a standard course and a manual course) and operation data, such as a washing water temperature and the addition of a rinsing mode, to the control unit 62 according to a user's instructions.

The washing courses include a standard course and a manual course. In the standard course, a water supplying mode to supply washing water, a washing mode to wash dishes by spraying the washing water onto the dishes after the water supplying mode, a heating mode to heat the washing water to a temperature suitable to wash and rinse before spraying the washing water onto the dishes, a draining mode to drain the washing water to the outside after the washing mode, and a drying mode to dry the dishes after the washing mode are sequentially operated. Further, in the manual course, the respective modes, which are selected according to conditions, are operated.

The control unit 62 is a microcomputer, for example, to operate the dish washer according to the operation data inputted from the input unit 60 to control the washing, rinsing, and drying modes. The control unit 62 sets an amount of the washing water in preliminary modes, including a preliminary washing mode and a preliminary rinsing mode, in which the heater 30 is not operated, to be smaller than an amount of the washing water in main modes, including a main washing mode and a last rinsing mode, in which the heater 30 is operated. For example, in the standard course, in the case that the amount of the washing water required in each of the respective modes is a first water level (approximately 5 L), the above necessary amount (5 L) of the washing water is supplied in each of the main modes, including the main washing mode and the last rinsing mode, and an amount (i.e., 4 L, a second water level) of the washing water that is smaller than the necessary amount of the washing water by approximately 20% is supplied in each of the preliminary modes, i.e., the preliminary washing mode and the preliminary rinsing mode. Thereby, the total amount of the washing water consumed in the entirety of the modes is reduced by approximately 10%.

In order to assure the washing performance of the dish washer, which may be deteriorated due to the reduction of the amount of the washing water consumed, the control unit 62 carries out a circulation operation in which only the upper and middle spray nozzles 26a and 26b spray the washing water in the preliminary modes, i.e., the preliminary washing mode and the preliminary rinsing mode. Thereby, dishes accommodated in the lower dish basket 22b are washed out by the washing water sprayed from the middle spray nozzle 26b and the falling water.

The driving unit 64 drives the heater 30, the circulation pump 46, the drain pump 48, the drain valve 50, a water supply valve 66, etc. according to driving control signals from the control unit 62. The water supply valve 66 controls the supply of the washing water to the inside of the washing tub 20.

The display unit 68 displays the operating state and errors of the dish washer according to a display control signal from the control unit 62.

Hereinafter, the operation and effects of the above dish washer and a method of controlling the same will be described.

FIGS. 3A to 3C are flow charts to illustrate a method of controlling a dish washer in accordance with the present embodiment.

When a user selects a washing course (for example, the standard course) and desired operation data under the condition that dishes to be washed are accommodated in the dish baskets 22a and 22b in the washing tub 20, the operation data selected by the user is inputted to the control unit 62 through the input unit 60.

Thus, the control unit 62 performs washing and rinsing modes according to the operation data inputted from the input unit 60. First, the control unit 62 determines whether or not the washing course selected by the user is a standard course (100).

When it is determined that the washing course selected by the user is the standard course, the control unit 62 operates the water supply valve 66 through the driving unit 64, and thus the washing water required in the preliminary washing mode is supplied to the inside of the washing tub 20 (102). When it is determined that the washing course selected by the user is not the standard course, the procedure returns to operation 100.

Thereafter, the water level sensing unit 58 senses the amount of the washing water supplied to the inside of the washing tub 20 in the preliminary washing mode, and determines whether or not the sensed amount reaches the predetermined second water level (104). The amount of the washing water is smaller than the amount of the washing water required in the main washing mode by approximately 20%, for example, approximately 4 L.

When it is determined that the sensed amount does not reach the second water level, the washing water is continuously supplied to the inside of the washing tub 20 until the sensed amount reaches the predetermined second water level, and when it is determined that the sensed amount reaches the second water level, the control unit 62 switches off the water supply valve 66, and thus the supply of the washing water is stopped (106).

The washing water supplied to the inside of the washing tub 20 is collected in the sump 42 provided under the washing tub 20, and is transferred to the upper spray nozzle 26a and the middle spray nozzle 26b through the first supply pipe 28a by the pumping action of the circulation pump 46 in the sump 42. Then, the upper and middle spray nozzles 26a and 26b spray the washing water onto the dishes having contaminants stuck thereto that are accommodated in the dish baskets 22a and 22b at a high pressure. Thereby, the preliminary washing mode to moisten the dishes and expand the contaminants stuck to the dishes is performed (108).

In the preliminary washing mode, although the lower spray nozzle 26c is not operated and only the upper and middle spray nozzles 26a and 26b spray the washing water, since the area ratio of the spray holes of the middle and lower nozzles 26b and 26c is approximately 1.5:1, the dishes accommodated in the lower dish baskets 22b are sufficiently moistened by the washing water sprayed through the middle spray nozzle 26b and the falling water.

When the preliminary washing mode is carried out, the control unit 62 measures a time, and determines whether or not a predetermined preliminary washing time, approximately 15 minutes, for example has elapsed, i.e., whether or not the preliminary washing mode has been completed (110). When it is determined that the preliminary washing mode has not been completed, the procedure returns to operation 108, and the preliminary washing mode is continuously carried out until the preliminary washing time has elapsed.

As a result of the above determination, when it is determined that the preliminary washing mode has been completed, since the contaminants stuck to the dishes as well as the washing water are collected in the sump 42, the control unit 62 drains the washing water containing the contaminants through the drain pipe 52 by the operations of the drain pump 48 and the drain valve 50 (112).

Thereafter, the control unit 62 operates the water supply valve 66 to carry out the main washing mode after the preliminary washing mode, and thus the washing water required in the main washing mode is supplied to the inside of the washing tub 20 (114).

The water level sensing unit 58 senses the amount of the washing water supplied to the inside of the washing tub 20 in the main washing mode, and determines whether or not the sensed amount reaches the predetermined first water level, which is the amount of the washing water required in the main washing mode, i.e., approximately 5 L (116).

When it is determined that the sensed amount does not reach the first water level, the procedure returns to operation 114, and the washing water is continuously supplied to the inside of the washing tub 20 until the sensed amount reaches the predetermined first water level, and when it is determined that the sensed amount reaches the predetermined first water level, the control unit 62 switches off the water supply valve 66 so that the supply of the washing water is stopped (118).

The washing water supplied to the inside of the washing tub 20 is collected in the sump 42 provided under the washing tub 20 in the same manner as the preliminary washing mode, and the washing water collected in the sump 42 is heated to a predetermined temperature (approximately 50°) by the heater 30 (120), and simultaneously a detergent is put into the washing tub 20 through a detergent supply device (not shown).

Then, the warm washing water, having a temperature of approximately 50°, containing the detergent is transferred to the upper, middle, and lower spray nozzles 26a, 26b, and 26c through the first and second supply pipes 28a and 28b by the pumping action of the circulation pump 46 in the sump 42. Then, the upper, middle, and lower spray nozzles 26a, 26b, and 26c spray the washing water onto the dishes accommodated in the dish baskets 22a and 22b at a high pressure. Thereby, the main washing mode to remove the contaminants from the dishes is performed (122).

In the main washing mode, all of the upper, middle, and lower spray nozzles 26a, 26b, and 26c spray the washing water so that the washing water is sprayed to the dishes to effectively remove the contaminants from the dishes.

Further, in the main washing mode, when the sensed amount of the washing water becomes less than a predetermined low water level during the operation of the heater 30, the supply of the washing water is carried out so that the amount of the washing water is not less than the predetermined low water level.

When the main washing mode is carried out, the control unit 62 measures a time, and determines whether or not a predetermined main washing time, approximately 30 minutes, for example, has elapsed, i.e., whether or not the main washing mode has been completed (124). When it is determined that the main washing mode has not been completed, the procedure returns to operation 122, and the main washing mode is continuously carried out until the main washing time has elapsed.

As a result of the above determination, when it is determined that the main washing mode has been completed in the same manner as the preliminary washing mode, since the contaminants stuck to the dishes as well as the washing water are collected in the sump 42, the control unit 62 drains the washing water containing the contaminants through the drain pipe 52 by the operations of the drain pump 48 and the drain valve 50 (126).

Thereafter, the control unit 62 operates the water supply valve 66 to carry out the preliminary rinsing mode after the main washing mode, and thus the washing water (specifically, rinsing water) required in the preliminary rinsing mode is supplied to the inside of the washing tub 20 (128).

The water level sensing unit 58 senses the amount of the washing water (rinsing water) supplied to the inside of the washing tub 20 in the preliminary rinsing mode, and determines whether or not the sensed amount reaches the predetermined second water level (130). The amount of the washing water is smaller than the amount of the washing water required in the main rinsing mode by approximately 20%, i.e., approximately 4 L.

When it is determined that the sensed amount does not reach the second water level, the procedure returns to operation 128, and the washing water (rinsing water) is continuously supplied to the inside of the washing tub 20 until the sensed amount reaches the predetermined second water level. When it is determined that the sensed amount reaches the predetermined second water level, the control unit 62 switches off the water supply valve 66, and thus the supply of the washing water (rinsing water) is stopped (132).

The washing water (rinsing water) supplied to the inside of the washing tub 20 is collected in the sump 42 in the same manner as the preliminary washing mode and the main washing mode, and is transferred to the upper spray nozzle 26a and the middle spray nozzle 26b through the first supply pipe 28a by the pumping action of the circulation pump 46 in the sump 42. Then, the upper spray and middle spray nozzles 26a and 26b spray the washing water widely onto the dishes at a high pressure. Thereby, the preliminary rinsing mode to wash off the contaminants and the detergent fallen by the main washing mode is performed (134).

In the preliminary rinsing mode, although the lower spray nozzle 26c is not operated and only the upper and middle spray nozzles 26a and 26b spray the washing water, since the area ratio of the spray holes of the middle and lower nozzles 26b and 26c is approximately 1.5:1, the dishes accommodated in the lower dish baskets 22b are sufficiently rinsed by the washing water sprayed through the middle spray nozzle 26b and the falling water.

When the preliminary rinsing mode is carried out, the control unit 62 measures a time, and determines whether or not a predetermined preliminary rinsing time, approximately 5 minutes, for example, has elapsed, i.e., whether or not the preliminary rinsing mode has been completed (136). When it is determined that the preliminary rinsing mode has not been completed, the procedure returns to operation 134, and the preliminary rinsing mode is continuously carried out until the preliminary rinsing time has elapsed.

As a result of the above determination, when it is determined that the preliminary rinsing mode has been completed, since the contaminants and the detergent washed off by the washing water (rinsing water), as well as the washing water (rinsing water) are collected in the sump 42, the control unit 62 drains the washing water (rinsing water) containing the contaminants and the detergent through the drain pipe 52 by the operations of the drain pump 48 and the drain valve 50 (138).

Thereafter, the control unit 62 operates the water supply valve 66 to carry out the last rinsing mode after the preliminary rinsing mode, and thus the washing water (rinsing water) required in the last rinsing mode is supplied to the inside of the washing tub 20 (140).

The water level sensing unit 58 senses the amount of the washing water (rinsing water) supplied to the inside of the washing tub 20 in the last rinsing mode, and determines whether or not the sensed amount reaches the predetermined first water level, which is the amount of the washing water required in the main rinsing mode, i.e., approximately 5 L, for example (142).

When it is determined that the sensed amount does not reach the first water level, the procedure returns to operation 140, and the washing water (rinsing water) is continuously supplied to the inside of the washing tub 20 until the sensed amount reaches the predetermined first water level. When it is determined that the sensed amount reaches the first water level, the control unit 62 stops the supply of the washing water (rinsing water) (144).

The washing water (rinsing water) supplied to the inside of the washing tub 20 is collected in the sump 42 in the same manner as in the preliminary rinsing mode, the washing water (rinsing water) collected in the sump 42 is heated to a predetermined temperature (approximately 65°) by the heater 30 (146), and simultaneously a fabric softener is put into the washing tub 20 through a softener supply device (not shown).

The warm washing water, having a temperature of approximately 60°, for example, containing the fabric softener is transferred to the upper, middle, and lower spray nozzle 26a, 26b, and 26c through the first and second supply pipes 28a and 28b by the pumping action of the circulation pump 46. Then, the upper, middle, and lower spray nozzles 26a, 26b, and 26c spray the washing water (rinsing water) onto the dishes accommodated in the dish baskets 22a and 22b at a high pressure. Thereby, the last rinsing mode to remove fine particles of the contaminants from the dishes is performed (148).

In the last rinsing mode, all of the upper, middle, and lower spray nozzles 26a, 26b, and 26c spray the washing water (rinsing water) so that the washing water is sprayed to the dishes to effectively remove the fine particles of the contaminants from the dishes.

Further, in the last rinsing mode, when the sensed amount of the washing water (rinsing water) becomes less than a predetermined low water level during the operation of the heater 30, the supply of the washing water (rinsing water) is carried out so that the amount of the washing water (rinsing water) is not less than the predetermined low water level.

When the last rinsing mode is carried out, the control unit 62 measures a time, and determines whether or not a predetermined last rinsing time, approximately 30 minutes, for example, has elapsed, i.e., whether or not the last rinsing mode has been completed (150). When it is determined that the last rinsing mode has not been completed, the procedure returns to operation 148, and the last rinsing mode is continuously carried out until the last rinsing time has elapsed.

As a result of the above determination, when it is determined that the last rinsing mode has been completed, since the contaminants stuck to the dishes as well as the washing water (rinsing water) are collected in the sump 42 in the same manner as in the preliminary rinsing mode, the control unit 62 drains the washing water (rinsing water) containing the contaminants through the drain pipe 52 by the operations of the drain pump 48 and the drain valve 50 (152).

Consequently, the total amount of the washing water consumed in the standard course of the method of the present embodiment is 18 L, i.e., the sum of 4 L in the preliminary washing mode, 5 L in the main washing mode, 4 L in the preliminary rinsing mode, and 5 L in the last rinsing mode. Thus, the amount of the washing water in the standard course of the method of the present embodiment is reduced by approximately 10% compared with the amount of the washing water (5 L×4=20 L) in the standard course of the conventional method. Further, the increased area of the spray holes of the middle spray nozzle 26b prevents an increase of a washing time and a deterioration of a washing efficiency due to the reduction of the amount of the washing water consumed. Moreover, the operation of the lower spray nozzle 26c is decreased, and thus, when the dish washer is used for a long period of time, the maintenance of electric field products is easily achieved.

As apparent from the above description, the present embodiment provides a dish washer and a method of controlling the same, in which the amount of water consumed is reduced and a washing time is maintained while assuring a washing performance.

Further, the area ratio of spray holes of upper, middle, and lower nozzles is converted such that the amount of water sprayed from the middle nozzle is maximized, so as to increase the washing performance. Moreover, the amount of water consumed in preliminary modes carried out prior to main modes is decreased, so as to reduce the amount of water required in the entirety of the modes.

Although an embodiment has been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.