US20090056757A1

US20090056757A1 - Method of controlling dishwasher and dishwasher

Info

Publication number: US20090056757A1
Application number: US12/200,105
Authority: US
Inventors: Ro Mon Son; Joung Hoon Kim
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2007-08-31
Filing date: 2008-08-28
Publication date: 2009-03-05
Also published as: CN101199409A; KR20090022857A; DE102008045085A1

Abstract

A dishwasher and method of controlling a dishwasher are provided. In the dishwasher and the method, a heater in a sump begins to be driven when a measured fluid supply frequency measured before the supply of wash fluid into the sump is complete reaches a predefined value, and thus heats the wash fluid in the sump. Thus, it is possible to reduce the time taken to heat the wash fluid in the sump to a target temperature, thus reducing the operating time of the dishwasher.

Description

This application claims priority to Korean Patent Application No. 10-2007-0088507 filed in Korea on Aug. 31, 2007, the entirety of which is incorporated herein by reference in its entirely.

BACKGROUND

1. Field
This relates to a method of controlling a dishwasher and a dishwasher, and more particularly, to a method of controlling a dishwasher and a dishwasher in which a supply of wash fluid and operation of a heater can be effectively controlled.
2. Background
Dishwashers are appliances that wash dirty dishes with clean wash fluid sprayed from nozzles at high pressure. In general, dishwashers include a washing tub and a sump disposed below the tub that contains wash fluid. The operation of dishwashers are largely classified into a washing operation, a drain operation, a rinsing operation and a drying operation.
Dishwashers may use warm wash fluid in order to improve the performance of dishwashing or rinsing during a washing or rinsing operation. In order to provide warm wash fluid, dishwashers may include a heater provided in the sump so as to heat the wash fluid stored therein. However, driving a heater after the supply of wash fluid and heating the wash fluid in the sump to a target temperature is time- and energy-consuming.
In particular, it generally takes a considerable amount of time to heat a considerable amount of wash fluid to a high temperature of, for example 65° C., which causes the operating time of a dishwasher to increase.

SUMMARY

A method of controlling a dishwasher and a dishwasher is provided in which the operating time of a dishwasher can be reduced and energy efficiency can be improved by reducing the time taken to heat wash water in a sump to a target temperature.
A method of controlling a dishwasher as embodied and broadly described herein may include supplying wash water into a sump until the flow rate of wash water measured by a flow rate detection device reaches a first set value; and heating the wash water in the sump by driving a heater if the flow rate of wash water measured by a flow rate detection device reaches a second set value, the second set value being less than the first set value.
A dishwasher as embodied and broadly described herein may include a sump; a water supply device which supplies wash water into the sump; a heater which heats the wash water in the sump; and a control unit which controls the heater to heat the wash water in the sump during the supply of wash water into the sump.
In accordance with embodiments as broadly described herein, a heater in a sump is driven and thus heats wash water in the sump when a measured flow rate reaches a second set value. Thus, it is possible to reduce the time taken to heat the wash water in the sump to a target temperature, thus reducing operating time of a dishwasher. In addition, it is possible to improve energy efficiency due to convection in the sump.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein:

FIG. 1 illustrates a cross-sectional view of a dishwasher according to an exemplary embodiment as broadly described herein;

FIG. 2 illustrates a schematic diagram of an airbrake of the dishwasher shown in FIG. 1;

FIG. 3 illustrates a block diagram of the dishwasher shown in FIG. 1; and

FIG. 4 illustrates a flowchart of a method of controlling a dishwasher according to an exemplary embodiment as broadly described herein.

DETAILED DESCRIPTION

Exemplary embodiments will hereinafter be described in detail with reference to the accompanying drawings.
Referring to FIG. 1, a dishwasher 100 as embodied and broadly described herein includes a tub 110 for washing dishes, a door 111 disposed at the front of the tub 110 to open/close the washing tub 110, a sump 120 disposed in the middle of the bottom of the tub 110 to store wash fluid, a heater 115 disposed in the sump 120 to heat wash fluid in the sump 120, and upper and lower racks 131 and 132 movably positioned in the tub 110 to hold dishes.
The dishwasher 100 also includes a washing pump 121 which pumps wash fluid out of the sump 120 at high pressure, a washing motor 122 disposed on one side of the washing pump 121 to drive the washing pump 121, a guide 126 which guides the flow of the wash fluid pumped by the washing pump 121, a lower nozzle 123 disposed above the sump 120 to spray wash fluid up toward the lower rack 132, an upper nozzle 124 connected to the guide 126 disposed below the upper rack 131 to spray wash fluid up toward the upper rack 131, a top nozzle 125 disposed at the ceiling of the tub 110 to spray wash fluid down to the upper rack 131, a drain pump 141 disposed on one side of the sump 120 to discharge wash fluid from the sump 120, and a drain motor 142 which drives the drain pump 141.
Referring to FIG. 2, the dishwasher 100 also includes an airbrake 160 attached on an external lateral surface of the tub 110 to guide wash fluid supplied by an external source into the sump 120 and to control the flow rate of wash fluid supplied into the sump 120.
The airbrake 160 includes a supply hose connector 161 through which wash fluid for washing dishes is supplied and a supply path 162 which is connected to the supply hose connector 161 and is U-shaped. A flow rate detector 150 is installed in the airbrake 160. The flow rate detector 150 is connected to the fluid supply path 162. The flow rate detector 150 is rotated by wash fluid supplied into the sump 120 and measures the flow rate of wash fluid supplied into the sump 120.
Referring to FIG. 2, the flow rate detector 150 includes an impeller 151 a rotated by the energy of wash fluid supplied into the sump 120, and a magnet 151 b disposed on the outer circumferential surface of the impeller 151 a.
FIG. 3 illustrates a block diagram of the dishwasher 100. Referring to FIG. 3, the dishwasher 100 includes the flow rate detector 150 which measures the flow rate of wash fluid supplied by an external source, a temperature sensor 155 disposed in the sump 120 to measure the temperature of wash fluid in the sump 120, a controller 170 that converts a measured flow rate provided by the flow rate detector 150 into a supply frequency and controls the operation of the heater 115 in the sump 120 according to the supply frequency, and a memory 175 which stores a first set value indicating a supply frequency when the supply of wash fluid into the sump 120 is complete and a second set value indicating a reference supply frequency for determining when to initiate the operation of the heater 115 in the sump 120. The controller 170 controls the general operation of the dishwasher 100.
A flowmeter may be used as the flow rate detector 150. The flow rate detector 150 is disposed in the airbrake 160, and is rotated by wash fluid supplied into the sump 120, and thus measures the flow rate of wash fluid supplied into the sump 120. The flow rate detector 150 includes the impeller 151 a, which is rotated by the energy of wash fluid supplied into the sump 120, and the magnet 151 b, which is disposed on the outer circumferential surface of the impeller 151 a. A hall sensor (not shown) is disposed near the flow rate detector 150. The hall sensor senses a magnetic field generated by the magnet 151 b upon the rotation of the impeller 151 a and generates a corresponding pulse.
Wash fluid supplied through the supply hose connector 161 of the airbrake 160 flows along the supply path 162 and drops, thereby rotating the impeller 151 a of the flow rate detector 150. Then, the hall sensor senses a magnetic field generated by the magnet 151 b and generates a corresponding pulse. Thereafter, the pulse generated by the hall sensor is transmitted to the controller 170, and is then transmitted into a supply frequency corresponding to the flow rate of wash fluid measured by the flow rate detector 150.
The controller 170 controls the opening and closing of the supply valve 165 and the operation of the heater 115 based on the flow rate of wash fluid measured by the flow rate detector 150.
The controller 170 may control the supply of wash fluid into the sump 120 by supplying wash fluid into the sump 120 until a supply frequency corresponding to the flow rate of wash fluid measured by the flow rate detector 150 reaches the first set value present in the memory 175. That is, if the supply frequency corresponding to the flow rate of wash fluid measured by the flow rate detector 150 reaches the first set value, the controller 170 may close the supply valve 165.
The first set value indicates a supply frequency when the supply of wash fluid into the sump 120 is complete. If the upper nozzle 124 and the lower nozzle 123 are alternately driven, the first set value may be set to about 460 Hz. Alternatively, if only the lower nozzle 123 is driven because only a few dishes are loaded in the tub 110, the first set value may be set lower than 460 Hz.
In order to control the operation of the heater 115, the controller 170 may compare a supply frequency corresponding to the flow rate of wash fluid measured by the flow rate detector 150 with the second set value present in the memory 175. Thereafter, if the supply frequency corresponding to the flow rate of wash fluid measured by the flow rate detector 150 reaches the second set value, the controller 170 may turn on the heater 115 in the sump 120 and may thus heat the wash fluid in the sump 120.
The second set value indicates a reference supply frequency for determining when to initiate the operation of the heater 115 in the sump 120. The second set value may be less than the first set value. The second set value may be set based on the time when the heater 115 begins to be immersed in wash fluid.
The heater 115 generally begins to be immersed in wash fluid when the supply frequency corresponding to the flow rate of wash fluid measured by the flow rate detector 150 reaches 150 Hz. Thus, the second set value may be set to 150-250 Hz. In order to prevent the heater 115 from generating heat even when being in a standby state, the second set value may be set to 200 Hz or higher.
Typically, wash fluid is supplied into the sump 120, and then the heater 115 is driven during the driving of the washing pump 121, thereby heating the wash fluid in the sump 120. On the other hand, in the exemplary embodiment of FIGS. 1 through 3, the heater 115 is driven before the supply of wash fluid into the sump 120 is complete. More specifically, the heater 115 is driven and thus heats the wash fluid in the sump 120 when the supply frequency corresponding to the flow rate of wash fluid measured by the flow rate detector 150 reaches the second set value.
Therefore, according to this exemplary embodiment, it is possible to reduce the time taken to heat the wash fluid in the sump 120 to a target temperature and thus to reduce the operating time of the dishwasher 100. In addition, it is possible to improve energy efficiency due to convection in the sump 120.
The flow rate detector 150 is not restricted to a flowmeter. That is, various devices, other than a flowmeter, may be used as the flow rate detector 150 as long as they can measure the flow rate of wash fluid supplied into the sump 120.
For example, a pressure switch may be used as the flow rate detector 150. In this case, the pressure switch may be disposed at the bottom of the sump 120 to measure pressure in the sump 120. Then, the measured pressure may be transmitted to the controller 170, and the controller 170 may convert the measured pressure into a supply frequency.
A method of controlling the dishwasher 100 according to an exemplary embodiment as broadly described herein will hereinafter be described in detail, mainly focusing on the control of the supply of wash fluid and the control of the operation of the heater 115.
FIG. 4 illustrates a flowchart of a method of controlling the dishwasher 100 according to an exemplary embodiment as broadly described herein. In the exemplary embodiment of FIG. 4, a flowmeter is used as the flow rate detector 150, the first set value is set to 450 Hz, and the second set value is set to 200 Hz.
When a request for operation of the dishwasher 100 is issued by a user, the controller 170 supplies wash fluid into the sump 120 by opening the supply valve 165 (S110). Wash fluid supplied by an external source is injected into the sump 120 via the airbrake 160.
Once the supply of wash fluid into the sump 120 begins, the flow rate detector 150 in the airbrake 160 measures the flow rate of wash fluid supplied into the sump 120 and thus determines a supply frequency based on the result of the measurement (S120). More specifically, wash fluid injected into the flow rate detector 150 through the supply path 162 of the airbrake 160 rotates the impeller 151 a, and the magnet 151 b generates a magnetic field upon the rotation of the impeller 151 a. The hall sensor, which is disposed near the flow rate detector 150, detects the magnetic field generated by the magnet 151 b and generates a corresponding pulse. Thereafter, the pulse generated by the hall sensor is transmitted to the controller 170, and the controller 170 converts the pulse generated by the hall sensor into a supply frequency.
During the supply of wash fluid into the sump 120, the controller 170 determines whether a supply frequency corresponding to a measured flow rate provided by the flow rate detector 150 reaches the second set value, i.e., 200 Hz, or the point at which the heater 115 is immersed (S130).
If the supply frequency corresponding to the measured flow rate reaches 200 Hz, the controller 170 turns on the heater 115 in the sump 120 and thus heats the wash fluid in the sump 120 (S140). In short, in the exemplary embodiment of FIG. 4, the controller 170 drives the heater 115 and thus heats the wash fluid in the sump 120 as fluid continues to be supplied to the sump 120, and before the supply of wash fluid into the sump 120 is complete.
During the heating of the wash fluid in the sump 120, the controller 170 determines whether the supply frequency corresponding to the measured flow rate reaches the first set value, i.e., 460 Hz (S150).
If the water supply frequency corresponding to the measured flow rate reaches 460 Hz, the controller 170 terminates the supply of wash fluid into the sump 120 by closing the supply valve 165 (S160).
Once the supply of wash fluid into the sump 120 is complete, the controller 170 turns on the washing motor 122 and thus drives the washing pump 121 so as to pump wash fluid out of the sump 120 at high pressure (S170). As a result, a washing operation is performed on dishes held by the upper rack 131 and/or the lower rack 132.
During the washing operation, the controller 170 determines whether a temperature measured from the wash fluid in the sump 120 by the temperature sensor 155 reaches a target temperature (S180). The target temperature may be an optimum wash fluid temperature for use in a washing operation. The target temperature may be automatically set according to a washing program chosen by the user or may be set manually by the user.
If the measured wash fluid temperature reaches the target temperature, the controller 170 terminates the heating of the wash fluid in the sump 120 by turning off the heater 115 in the sump 120 (S190). During the washing operation, the controller 170 may alternately turn on and off the heater 115 so as to maintain the wash fluid in the sump 120 at the target temperature.
Thereafter, the controller 170 performs a subsequent operation (S200). That is, the controller 170 may sequentially perform a rinsing operation for rinsing dishes loaded in the tub 110 and a drying operation for drying the dishes loaded in the tub 110, thereby completing the operation of the dishwasher 100.
It has been described above how to control the supply of wash fluid and the operation of the heater 115 during a washing operation. However, embodiments as broadly descried herein are not restricted to this. That is, the supply of wash fluid and the operation of the heater 115 may be controlled in a similar manner during a rinsing operation.
Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” “certain embodiment,” “alternative embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment as broadly described herein. The appearances of such phrases in various places in the specification are not necessarily all referring to; the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments.
Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, numerous variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

Claims

1. A method of controlling a dishwasher, the method comprising:

supplying wash fluid into a sump until a flow rate of the wash fluid measured by a flow rate detector reaches a first set value; and

heating the wash fluid in the sump by operating a heater when the flow rate of the wash fluid measured by the flow rate detector reaches a second set value, the second set value being less than the first set value.

2. The method of claim 1, wherein the heater is positioned at a bottom portion of the sump and the second set value is based on a point at which the heater begins to be immersed in wash fluid.

3. The method of claim 1, wherein the first set value is between approximately 150 and 250 Hz.

4. The method of claim 1, wherein heating the wash fluid comprises heating the wash fluid in the sump until a fluid temperature in the sump reaches a target temperature.

5. The method of claim 1, wherein the flow rate detector comprises a flowmeter, and wherein supplying wash fluid into a sump comprises measuring the flow rate of wash fluid supplied into the sump as the flow of wash fluid rotates the flowmeter.

6. The method of claim 1, wherein the flow rate detector comprises a pressure switch provided in the sump to measure a fluid pressure in the sump.

7. A dishwasher, comprising:

a sump;

a supply device that supplies wash fluid to the sump;

a heater that heats the wash fluid in the sump; and

a controller that controls the heater to heat the wash fluid in the sump as wash fluid is supplied to the sump.

8. The dishwasher of claim 7, further comprising a flow rate detector that measures a flow rate of wash fluid supplied to the sump, wherein the controller determines when to operate the heater based on the measured flow rate provided by the flow rate detector.

9. The dishwasher of claim 8, wherein the flow rate detector comprises:

an impeller that is rotated by incoming wash fluid; and

a magnet that generates a magnetic field as the impeller rotates.

10. The dishwasher of claim 9, wherein the controller converts a pulse that corresponds to the magnetic field generated by the magnet, into a supply frequency that corresponds to the measured flow rate.

11. The dishwasher of claim 8, wherein the controller supplies wash fluid to the sump until the flow rate measured by the flow rate detector reaches a first set value, and wherein the controller heats the wash fluid in the sump by operating a heater when the flow rate measured by the flow rate detector reaches a second set value.

12. The dishwasher of claim 11, wherein the second set value is less than the first set value.

13. The dishwasher of claim 11, wherein the second set value is based on a point at which the heater begins to be immersed in wash fluid.

14. The dishwasher of claim 11, wherein the controller operates the heater for a first set time, and terminates operation of the heater for a second set time after the first set time has elapsed when the flow rate measured by the flow rate detector reaches the second set value.

15. The dishwasher of claim 11, wherein the controller operates the heater when the flow rate detector determines that wash fluid is being supplied to the sump.

16. The dishwasher of claim 7, wherein the controller measures an amount of time taken to supply wash fluid to the sump and operates the heater when the measured amount of time exceeds a predefined amount.

17. A method of controlling a dishwasher, the method comprising:

supplying wash fluid to a sump;

measuring a flow rate of the wash fluid as it is supplied to the sump, and comparing the measured flow rate to a first set value and a second set value;

turning on a heater and heating the was fluid collected in the sump when the measured flow rate is greater than or equal to the second set value; and

continuing to supply wash fluid to the sump while the heater heats the wash fluid collected in the sump until the measured flow rate is equal to the first set value.

18. The dishwasher of claim 17, wherein measuring a flow rate of the wash fluid comprises:

directing the wash fluid across an impeller to rotate the impeller;

generating a magnetic field using at least one, magnet in response to the rotation of the impeller; and

generating a fluid supply frequency based on the magnetic field generated by the at least one magnet that corresponds to a flow rate of the wash fluid being supplied to the sump.

19. The dishwasher of claim 18, wherein turning on a heater and heating the wash fluid collected in the sump when the measured flow rate is greater than or equal to the second set value comprises turning on the heater when the fluid supply frequency is greater than or equal to the second set value, wherein a fluid supply frequency of the second set value corresponds to a point at which the heater is immersed in the wash fluid collected in the sump.

20. The dishwasher of claim 19, wherein continuing to supply wash fluid to the sump while the heater heats the wash fluid collected in the sump until the measured flow rate is equal to the first set value comprises supplying wash fluid to the sump until the fluid supply frequency is equal to the first set value, wherein a fluid supply frequency of the first set value corresponds to a point at which the sump is at a predefined fill level required for a selected operation of the dishwasher.

21. The dishwasher of claim 20, further comprising continuing to heat the wash fluid collected in the sump until a temperature thereof is greater than or equal to a target temperature, and then shutting off the heater.

22. The dishwasher of claim 21, further comprising intermittently turning the heater on and off to maintain the wash fluid collected in the sump at the target temperature.