U.S. patent application number 10/145815 was filed with the patent office on 2003-07-31 for dishwasher and method of operation.
This patent application is currently assigned to LG Electronics Inc.. Invention is credited to Choi, Byung Keol, Han, Dae Yeong, Jeon, Si Moon, Lee, Tae Hee.
Application Number | 20030140947 10/145815 |
Document ID | / |
Family ID | 19719022 |
Filed Date | 2003-07-31 |
United States Patent
Application |
20030140947 |
Kind Code |
A1 |
Han, Dae Yeong ; et
al. |
July 31, 2003 |
Dishwasher and method of operation
Abstract
A dishwasher includes an interior tub and a wash pump for
pumping wash liquid to wash dishes located in the interior tub. A
pump motor for driving the wash pump is regulated by a control unit
that adjusts a spraying pressure of wash liquid. The method for
operating a dishwasher includes sensing the degree to which wash
liquid is soiled and regulating the speed of a pump motor for
spraying wash liquid against the dishes, depending upon the degree
to which the wash liquid is soiled. The regulation of the pump
motor adjusts the wash liquid spraying pressure.
Inventors: |
Han, Dae Yeong; (Seoul,
KR) ; Lee, Tae Hee; (Seoul, KR) ; Choi, Byung
Keol; (Kyungki-do, KR) ; Jeon, Si Moon;
(Seoul, KR) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1950 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Assignee: |
LG Electronics Inc.
Seoul
KR
|
Family ID: |
19719022 |
Appl. No.: |
10/145815 |
Filed: |
May 16, 2002 |
Current U.S.
Class: |
134/18 ;
134/25.2; 134/57D |
Current CPC
Class: |
A47L 15/4225 20130101;
A47L 15/4289 20130101; A47L 2501/05 20130101; Y02B 40/00 20130101;
A47L 2301/04 20130101; A47L 2401/10 20130101 |
Class at
Publication: |
134/18 ;
134/25.2; 134/57.00D |
International
Class: |
A47L 015/46 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2002 |
KR |
2002-05710 |
Claims
What is claimed:
1. A dishwasher comprising: an interior tub in which dishes to be
washed are located; a wash pump for pumping wash liquid for washing
the dishes located in the interior tub; a pump motor for driving
the wash pump; spraying means for spraying wash liquid onto the
dishes; and a control unit for regulating the speed of the pump
motor to adjust a spraying pressure of wash liquid sprayed from the
spraying means.
2. The dishwasher as set forth in claim 1, wherein the control unit
regulates the speed of the pump motor by controlling a phase of
power inputted to the pump motor.
3. The dishwasher as set forth in claim 1, further comprising a
sensor for sensing the degree to which the wash liquid is soiled,
upon washing the dishes.
4. The dishwasher as set forth in claim 3, wherein the sensor
senses a soil concentration in the wash liquid and calculates a
rate of concentration change of the wash liquid.
5. The dishwasher as set forth in claim 4, wherein when a sensed
soil concentration in the wash liquid is constant and the
calculated rate of concentration change is lower than a previous
value, the control unit implements a next dishwashing
procedure.
6. The dishwasher as set forth in claim 2, wherein the control unit
comprises: a microcomputer for generating and outputting a trigger
signal to control the supply of power from a power source to the
pump motor; and a phase controlling driver circuit for controlling
a phase of power to be supplied from the power source to the pump
motor in response to the trigger signal generated and outputted by
the microcomputer, wherein the phase controlling driver circuit
applies a resulting power to the pump motor.
7. The dishwasher as set forth in claim 6, wherein the
microcomputer controls the phase controlling driver circuit so that
a first speed of the pump motor, when a sensed soil concentration
is higher than a reference value, is greater than a second speed of
the pump motor when a sensed soil concentration is lower than the
reference value, wherein a first wash liquid spraying pressure is
associated with the first speed and a second wash liquid spraying
pressure is associated with the second speed and the first liquid
spraying pressure is greater than the second liquid spraying
pressure.
8. The dishwasher as set forth in claim 1, further comprising a
spraying pressure adjustment control for allowing an operator to
regulate the speed of the pump motor.
9. A method for operating a dishwasher, comprising: sensing a
degree to which wash liquid is soiled, upon washing the dishes;
regulating a speed of a pump motor for spraying wash liquid onto
dishes in the dishwasher, the regulation depending upon the degree
to which wash liquid is soiled as sensed during the sensing; and
adjusting a wash liquid spraying pressure depending upon the speed
of the pump motor.
10. The method as set forth in claim 9, further comprising
determining the degree of soil concentration in the wash liquid and
calculating a rate of concentration change of the wash liquid.
11. The method as set forth in claim 10, further comprising
implementing a next dishwashing procedure when the sensed soil
concentration is constant and the calculated rate of concentration
change is lower than a previous value.
12. The method as set forth in claim 9, wherein the speed of the
pump motor is regulated such that a first level of power inputted
to the pump motor, when a sensed soil concentration is higher than
a reference value, is greater than a second level of power inputted
to the pump motor when a sensed soil concentration is lower than
the reference value.
13. The method as set forth in claim 9, further comprising
receiving an instruction from an operator to adjust the wash liquid
spraying pressure, wherein the speed of the pump motor is regulated
in response to the instruction for adjusting the wash liquid
spraying pressure.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method and apparatus for
washing dishes and in particular, to an automatic dishwasher and a
method for operating the same, wherein a liquid spraying pressure
is adjusted according to the degree to which the dishes are soiled,
thus optimizing energy efficiency while preventing damage to the
dishes.
[0003] 2. Description of the Related Art
[0004] Automatic dishwashers have been widely used throughout the
world in many homes and commercial establishments, e.g.,
restaurants. A known dishwasher is described with reference to FIG.
1. The known dishwasher includes an interior tub 1. Wash liquid
filled in the interior tub 1 is drawn by a wash pump 5 and is
supplied to lower and upper wash arms 9 and 10 through flow paths 6
and 7. Wash liquid supplied to the lower and upper wash arms 9 and
10 is sprayed, through nozzles 14 formed therein, onto dishes
supported on lower and upper dish racks 11 and 12 to remove food
substances therefrom. Wash liquid including the food substances
removed from the dishes flows toward a bottom of the interior tub 1
to be collected in a sump 2. The wash liquid collected in the sump
2 passes through a filter 3 to remove solid particulate. Then, the
filtered wash liquid is drawn again through a flow path 4 by the
wash pump 5 to be recirculated over the dishes. After the
dishwashing operation is completed, wash liquid is collected in the
sump 2 and is discharged out of the tub 1, along with the separated
substances (i.e., soiled materials), through a drain pump 13.
[0005] However, the known dishwasher as discussed has various
drawbacks. Specifically, a pump motor for driving the wash pump 5
is operated at a constant speed in revolutions per minute (rpms)
such that the wash pump 5 sprays wash liquid through nozzles 14 at
a constant spraying pressure, regardless of the degree to which the
dishes are soiled.
[0006] Consequently, even when washing lightly soiled dishes, the
identical dishwashing operation designed to wash highly soiled
dishes is performed, resulting in a waste of wash liquid and
energy. Moreover, with the aforementioned dishwasher, damage may be
done to dishes that are expensive or dishes having low impact
resistance, such as crystal, for example.
SUMMARY OF THE INVENTION
[0007] Accordingly, the present invention has been made in an
effort to solve the problems occurring in the related art, and an
object of the present invention is to provide a dishwasher and a
method for operating the same, wherein a wash liquid spraying
pressure can be adjusted depending upon the degree to which the
dishes are soiled, to avoid unnecessary consumption of wash liquid
and energy. Furthermore, a wash liquid spraying pressure can be
adjusted as desired by a user, to protect dishes having inferior
impact resistance.
[0008] In order to achieve the above objects, according to one
aspect of the present invention, a dishwasher is provided that
includes an interior tub in which dishes to be washed are located;
a wash pump for pumping wash liquid for washing the dishes located
in the interior tub; a pump motor for driving the wash pump; a
spraying mechanism for spraying wash liquid onto the dishes; and a
control unit for regulating a speed of the pump motor thereby to
adjust a spraying pressure of wash liquid sprayed from the spraying
mechanism.
[0009] According to another aspect of the present invention, a
method for operating a dishwasher includes sensing the degree to
which the wash liquid is soiled upon washing dishes located in the
dishwasher; regulating a speed of a pump motor for spraying wash
liquid onto the dishes, depending upon the degree to which the wash
liquid is soiled as sensed; and adjusting a wash liquid spraying
pressure by regulating the speed of the pump motor.
[0010] The method may further include determining the degree of
soil concentration in the wash liquid and calculating a rate of
concentration change of the wash liquid. Additionally, a next
dishwashing procedure may be implemented when the sensed soil
concentration is constant and the calculated rate of concentration
change is lower than a previous value.
[0011] The speed of the pump motor is regulated such that a first
level of power inputted to the pump motor, when a sensed soil
concentration is higher than a reference value, is greater than a
second level of power inputted to the pump motor, when sensed soil
concentration is lower than a reference value. Also, an instruction
may be received from an operator to adjust the wash liquid spraying
pressure, such that the speed of the pump motor is regulated in
response to the instruction for adjusting the wash liquid spraying
pressure.
[0012] According to yet another aspect of the present invention, a
dishwasher is provided that includes an interior tub in which
dishes to be washed are located, a wash pump for pumping wash
liquid for washing the dishes located in the interior tub, a pump
motor for driving the wash pump, a spraying mechanism for spraying
wash liquid onto the dishes; and a control unit for regulating the
speed of the pump motor to adjust a spraying pressure of wash
liquid sprayed from the spraying mechanism.
[0013] The control unit regulates the speed of the pump motor by
controlling a phase of power inputted to the pump motor. A sensor
is also included for sensing the degree to which the wash liquid is
soiled, upon washing the dishes. Specifically, the sensor senses a
soil concentration in the wash liquid and calculates a rate of
concentration change of the wash liquid. When the sensed soil
concentration in the wash liquid is constant and the calculated
rate of concentration change is lower than a previous value, the
control unit implements a next dishwashing procedure.
[0014] The control unit includes a microcomputer for generating and
outputting a trigger signal to control the supply of power from a
power source to the pump motor; and a phase controlling driver
circuit for controlling a phase of power to be supplied from the
power source to the pump motor in response to the trigger signal
generated and outputted by the microcomputer. As a result, the
phase controlling driver circuit applies a resulting power to the
pump motor.
[0015] The microcomputer controls the phase controlling driver
circuit so that a first speed of the pump motor, when a sensed soil
concentration is higher than a reference value, is greater than a
second speed of the pump motor when a sensed soil concentration is
lower than the reference value. Specifically, the higher speed of
the pump motor in turn creates a higher wash liquid spraying
pressure than does a lower pump motor speed.
[0016] Optionally, an operator may control the wash liquid spraying
pressure by actuating a spraying pressure adjustment control.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The above objects, and other features and advantages of the
present invention will be made apparent from the following detailed
description of the preferred embodiments, given as non-limiting
examples, with reference to the accompanying drawings, in
which:
[0018] FIG. 1 is an exemplary front view of a prior art
dishwasher;
[0019] FIG. 2 is an exemplary block diagram illustrating a
dishwasher schematic, according to an aspect of the present
invention;
[0020] FIGS. 3a, 3b and 3c are exemplary graphs illustrating
waveforms of power inputted to a pump motor during operation of the
dishwasher, according to an aspect of the present invention;
and
[0021] FIG. 4 is an exemplary flow chart depicting a method for
operating the dishwasher according to an aspect of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] The particulars shown herein are by way of example and for
purposes of illustrative discussion of the embodiments of the
present invention only and are presented in the cause of providing
what is believed to be the most useful and readily understood
description of the principles and conceptual aspects of the present
invention. In this regard, no attempt is made to show structural
details of the present invention in more detail than is necessary
for the fundamental understanding of the present invention, and the
description is taken with the drawings making apparent to those
skilled in the art how the forms of the present invention may be
embodied in practice.
[0023] Reference will now be made in greater detail to a preferred
embodiment of the invention, an example of which is illustrated in
the accompanying drawings. Wherever possible, the same reference
numerals will be used throughout the drawings and the description
to refer to the same or like parts.
[0024] FIG. 2 is an exemplary block diagram depicting a relevant
portion of a dishwasher (the non-illustrated portions being
conventional and substantially depicted in FIG. 1), according to an
aspect of the present invention. The dishwasher includes a pump
motor 30 and a control unit 20. The pump motor 30 drives a wash
pump (not shown) that pumps wash liquid through a spraying
mechanism (not shown) for spraying wash liquid onto dishes located
in an interior tub (not shown). The control unit 20 functions to
adjust the spraying pressure of the washing liquid by regulating
the speed (i.e., revolutions per minute or rpms) of the pump motor
30.
[0025] The control unit 20 includes a microcomputer 22 and a phase
controlling driver circuit 21. The microcomputer 22 generates and
outputs a trigger signal for controlling a supply of power from a
power source 35 to the pump motor 30. The phase controlling driver
circuit 21 controls a phase of power supplied from the power source
35 to the pump motor 30 in response to the trigger signal generated
and outputted by the microcomputer 22, and applies the resulting
power to the pump motor 30.
[0026] That is, the microcomputer 22 calculates an optimal speed of
the pump motor 30, and generates and outputs a trigger signal
corresponding to the calculated optimal speed of the pump motor 30.
Then, in response to the trigger signal, the phase controlling
driver circuit 21 controls the phase of power supplied from the
power source 35 to the pump motor 30. That is, a phase of power
supplied from the power source 35 to the pump motor 30 is
controlled in response to the trigger signal outputted from the
microcomputer 22. As a result, the speed of the pump motor 30 is
optimally regulated.
[0027] FIGS. 3a, 3b and 3c are exemplary graphs illustrating
waveforms of power outputted from the power source 35 and inputted
to the pump motor 30 in response to the trigger signals generated
and outputted by the microcomputer 22.
[0028] Specifically, power is supplied to the pump motor 30 for an
interval which extends from a position of a trigger signal
generated and outputted by the microcomputer 22 to a zero-crossing
point where a phase of power from the power source 35 is inverted,
and power supply is cut off for another interval which extends from
the zero-crossing point to a position of a next trigger signal.
Consequently, by controlling a position of the trigger signal,
power supplied to the pump motor 30 is changed, thereby regulating
the speed of the pump motor 30 and adjusting the liquid spraying
pressure.
[0029] The hatched portions of FIGS. 3a, 3b and 3c represent
amounts of power supplied to the pump motor 30 in response to
trigger signals. In FIGS. 3a through 3c, the dashed lines
illustrate waveforms of power outputted from the power source 35,
and the solid lines illustrate waveforms of trigger signals
outputted from the microcomputer 22. As can be readily seen from
FIGS. 3a, 3b and 3c, an interval, through which power is supplied
to the pump motor 30, extends from a position of a trigger signal
to a next zero-crossing point. That is, power supply to the pump
motor 30 has no relationship to a width of a trigger signal, and is
determined by a position where a trigger signal is initially
splashed.
[0030] FIGS. 3a, 3b and 3c illustrate waveforms in instances where
the wash liquid is sprayed at a high pressure, an intermediate
pressure and a low pressure, respectively. In FIG. 3a, since an
entire amount of power is inputted to the pump motor 30, the pump
motor 30 is rotated at high rpms. In FIGS. 3b and 3c, as only
portions of power are inputted to the pump motor 30, slip of the
pump motor 30 is increased, and thus, the pump motor 30 is rotated
at low rpms.
[0031] The dishwasher according to the present invention further
includes a soil degree sensor 25 for sensing the degree to which
the wash liquid is soiled. The soil degree sensor 25 senses the
degree of soil concentration in the wash liquid and calculates a
rate of concentration change of the wash liquid. Then, the soil
degree sensor 25 outputs the sensed soil concentration and the
calculated rate of concentration change to the microcomputer
22.
[0032] The microcomputer 22 outputs a control signal to the phase
controlling driver circuit 21, to adjust the wash liquid spraying
pressure depending upon the degree of soil concentration and the
rate of concentration change sensed and calculated by the soil
degree sensor 25. As a result, the amount of power supplied from
the power source 35 to the pump motor 30 is regulated and the wash
liquid spraying pressure is adjusted.
[0033] The dishwasher further includes a spraying pressure
adjustment control 24 for allowing the wash liquid spraying
pressure to be manually adjusted as desired by an operator. As the
operator manipulates the spraying pressure adjustment control 24,
an instruction for adjusting the wash liquid spraying pressure, as
indicated by the operator, is inputted to the microcomputer 22.
Accordingly, the microcomputer 22 transmits a control signal to the
phase controlling driver circuit 21 to regulate the speed of the
pump motor 30 in response to the inputted instruction.
[0034] The control unit 20 of the dishwasher controls other
programmed tasks which are required for washing dishes in the
dishwasher, e.g., actuation of wash and drain pumps, refilling of
fresh wash liquid, operating a heater, etc. The control unit 20 is
configured to implement a dishwashing procedure based on signals
sensed by a variety of sensors, including a level sensor or a
pressure sensor for sensing an amount of wash liquid filled in the
tub and a temperature sensor for preventing the dishwasher from
being overheated, for example.
[0035] Moreover, the control unit 20 further includes an
interrupter 23. The interrupter 23 is connected with the
microcomputer 22 to check a zero-crossing point of the power from
the power source 35, generate a zero-crossing point signal and
prevent an unnecessary signal from being transmitted to the
microcomputer 22.
[0036] The control unit 20 of the dishwasher is configured to alter
an amount of current applied to the pump motor 30, depending upon
the degree of soil concentration of the wash liquid sensed by the
soil degree sensor 25, and thereby regulate the speed of the pump
motor 30. Further, the control unit 20 allows the speed of the pump
motor 30 to be manually regulated as desired by the operator.
[0037] For example, when the operator desires to wash dishes made
of a material that is expensive or that has a low impact
resistance, such as crystal, the operator may manipulate the
spraying pressure adjustment control 24 to select a desired wash
liquid spraying pressure. Thus, the control unit 20 controls the
amount of current in response to the spraying pressure adjustment
instruction inputted via the spraying pressure adjustment control
24.
[0038] Wash liquid spraying pressures, which are determined
depending upon degrees of soil concentrations and rates of
concentration change sensed and calculated by the soil degree
sensor 25, are provided in TABLE 1.
1TABLE 1 Rate of Degree of Soil Concentration Wash Liquid
Concentration Change Spraying Pressure High High High Intermediate
Intermediate Constant Low Intermediate High Intermediate
Intermediate Intermediate Constant Low Low Intermediate
Intermediate Constant Low
[0039] As can be readily seen from TABLE 1, when the degree of soil
concentration is high and the rate of concentration change is high,
the control unit 20 determines that the dishes are highly soiled
and regulates the speed of the pump motor 30 to high, thus
supplying wash liquid at high pressure. Thus, a high pressure of
wash liquid is sprayed through the spraying mechanism. When the
soil concentration is high and the rate of concentration change is
intermediate, the control unit 20 determines that the soiled matter
is substantially removed from the dishes, and regulates the speed
of the pump motor 30 to intermediate thus supplying wash liquid at
intermediate pressure through the spraying mechanism. When the soil
concentration is low and a rate of concentration change is
constant, the control unit 20 determines that dishes are merely
slightly soiled and regulates the speed of the pump motor 30 to
low, thus supplying wash liquid at a low pressure the spraying
mechanism for a short period of time. In this instance, the amount
of wash liquid drawn by the wash pump is decreased, shortening
dishwashing time and reducing unnecessary energy consumption.
[0040] FIG. 4 is an exemplary flow chart depicting a method for
operating the dishwasher according to as aspect of the present
invention.
[0041] At step S1, during a dishwashing operation, the soil degree
sensor 25 senses a degree of soil concentration and calculates a
rate of concentration change.
[0042] At step S2, the control unit 20 determines, based on TABLE
1, a wash liquid spraying pressure based upon the degree of soil
concentration and the rate of concentration change determined by
the soil degree sensor 25. Also at step S2, the control unit 20
outputs a control signal to the phase controlling driver circuit
21.
[0043] At step S3, the phase controlling driver circuit 21
regulates the power source, in response to the trigger signal
inputted thereto, to supply power to the pump motor 30. As
described above with reference to FIGS. 3a, 3b and 3c, the power
supplied to the pump motor 30 is regulated depending upon a
position of the trigger signal.
[0044] At step S4, the speed of the pump motor 30 is determined
depending upon the power supplied in the step S3, the pump motor 30
drives the wash pump.
[0045] At step S5, the wash pump pumps wash liquid, thus spraying
the wash liquid through the spraying mechanism.
[0046] As apparent from the above description, the dishwasher and
the method for operating the same according to the present
invention provide advantages. Specifically, since the degree to
which the wash liquid is soiled is sensed and a magnitude of
current inputted to a pump motor is regulated depending upon the
degree to which the wash liquid is soiled, the wash liquid spraying
pressure may be adjusted to avoid wasting wash liquid and energy.
Moreover, the operator may adjust the wash liquid spraying
pressure, as desired, if washing dishes that are expensive or that
are made of delicate materials.
[0047] Although the invention has been described with reference to
exemplary embodiments, it is understood that the words that have
been used are words of description and illustration, rather than
words of limitation. Changes may be made within the purview of the
appended claims, as presently stated and as amended, without
departing from the scope and spirit of the invention in its
aspects. Although the invention has been described with reference
to particular means, materials and embodiments, the invention is
not intended to be limited to the particulars disclosed; rather,
the invention extends to all functionally equivalent structures,
methods and uses such as are within the scope of the appended
claims.
[0048] The present disclosure relates to subject matter contained
in priority Korean application No. 2002-05710, filed on Jan. 31,
2002, which is herein expressly incorporated by reference in its
entirety.
* * * * *