U.S. patent application number 13/565187 was filed with the patent office on 2014-02-06 for washing maching appliance with a drain pump.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. The applicant listed for this patent is Joshua David Flesch. Invention is credited to Joshua David Flesch.
Application Number | 20140033443 13/565187 |
Document ID | / |
Family ID | 50024030 |
Filed Date | 2014-02-06 |
United States Patent
Application |
20140033443 |
Kind Code |
A1 |
Flesch; Joshua David |
February 6, 2014 |
WASHING MACHING APPLIANCE WITH A DRAIN PUMP
Abstract
A washing machine appliance is provided. The washing machine
appliance includes a wash basket rotatably mounted within a wash
tub and a drain pump for removing liquid from the wash tub. During
a spin cycle of the washing machine appliance, the drain pump may
be activated during an acceleration portion of the spin cycle.
Further, the drain pump may be operated at a first duty cycle for a
first portion of a dwell step of the spin cycle and at a second
duty cycle for a second portion of the dwell step of the spin
cycle.
Inventors: |
Flesch; Joshua David;
(Louisville, KY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Flesch; Joshua David |
Louisville |
KY |
US |
|
|
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
50024030 |
Appl. No.: |
13/565187 |
Filed: |
August 2, 2012 |
Current U.S.
Class: |
8/137 ;
68/12.14 |
Current CPC
Class: |
D06F 23/04 20130101;
D06F 39/083 20130101; D06F 35/007 20130101 |
Class at
Publication: |
8/137 ;
68/12.14 |
International
Class: |
D06F 37/36 20060101
D06F037/36 |
Claims
1. A method for operating a washing machine appliance, the washing
machine appliance having a cabinet with a wash tub mounted therein,
the washing machine appliance also having a wash basket positioned
within the wash tub, the wash basket configured for receipt of
articles for washing and mounted for rotation relative to the
cabinet, the method comprising: initiating a spin cycle of the
washing machine appliance, the spin cycle comprising: an
acceleration step in which the wash basket accelerates from a first
angular velocity to a second angular velocity, the first angular
velocity being different than the second angular velocity, the
acceleration step of the spin cycle performed during an
acceleration step time interval; a dwell step in which the wash
basket rotates at about the second angular velocity, the dwell step
of the spin cycle performed during a dwell step time interval, the
dwell step time interval comprising a first portion and a second
portion; running the drain pump of the washing machine appliance
during the acceleration step of the spin cycle for about the
acceleration step time interval; operating the drain pump of the
washing machine appliance at a first duty cycle during the dwell
step of the spin cycle for about the first portion of the dwell
step time interval; and working the drain pump of the washing
machine appliance at a second duty cycle during the dwell step of
the spin cycle for about the second portion of the dwell step time
interval.
2. The method of claim 1, wherein the acceleration step and the
dwell step of the spin cycle are substantially sequential.
3. The method of claim 1, wherein the first duty cycle is greater
than the second duty cycle.
4. The method of claim 1, wherein the spin cycle of the washing
machine appliance further comprises an additional acceleration step
in which the wash basket accelerates from about the second angular
velocity to a third angular velocity, the third angular velocity
being different than the second angular velocity, the additional
acceleration step of the spin cycle performed during an additional
acceleration step time interval, and wherein the spin cycle of the
washing machine appliance also further comprises an additional
dwell step in which the wash basket rotates at about the third
angular velocity, the additional dwell step of the spin cycle
performed during an additional dwell step time interval, the
additional dwell step time interval having a first portion and a
second portion, the method further comprising the steps of: running
the drain pump of the washing machine appliance during the
additional acceleration step of the spin cycle for about the
additional acceleration step time interval; operating the drain
pump of the washing machine appliance at a third duty cycle during
the additional dwell step of the spin cycle for about the first
portion of the additional dwell step time interval; and working the
drain pump of the washing machine appliance at a fourth duty cycle
during the additional dwell step of the spin cycle for about the
second portion of the additional dwell step time interval.
5. The method of claim 4, wherein the acceleration step, the dwell
step, the additional acceleration step, and the additional dwell
step of the spin cycle are substantially sequential.
6. The method of claim 4, wherein the first duty cycle and the
third duty cycle are about equal, and the second duty cycle and the
fourth duty cycle are about equal.
7. The method of claim 4, wherein the third duty cycle is greater
than the fourth duty cycle.
8. The method of claim 1, wherein the spin cycle of the washing
machine appliance further comprises a brake step in which the wash
basket accelerates from about second angular velocity to about a
zero angular velocity, the zero angular velocity being different
than the second angular velocity, the method further comprising the
steps of: utilizing the drain pump of the washing machine appliance
during the brake step of the spin cycle for a predetermined period
of time.
9. The method of claim 8, wherein the predetermined period of time
is about thirty seconds.
10. The method of claim 1, wherein the second angular velocity is
between about eighty radians per second and about one hundred and
ten radians per second.
11. A washing machine appliance comprising: a cabinet; a wash tub
mounted within said cabinet, said wash tub configured for holding
liquid during operation of the washing machine appliance; a wash
basket rotatably mounted within said wash tub, said wash basket
configured for receipt of articles for washing; a motor in
mechanical communication with said wash basket such that said motor
selectively rotates said wash basket; a drain pump in fluid
communication with said wash tub, said drain pump configured for
selectively urging liquid out of said wash tub; and a processing
device in communication with said drain pump and said motor, said
processing device configured for: initiating said motor during a
spin cycle of the washing machine appliance, the spin cycle
comprising: an acceleration step in which said motor accelerates
said wash basket from a first angular velocity to a second angular
velocity, the first angular velocity being different than the
second angular velocity, the acceleration step of the spin cycle
performed during an acceleration step time interval; a dwell step
in which said motor rotates said wash basket at about the second
angular velocity, the dwell step of the spin cycle performed during
a dwell step time interval, the dwell step time interval having a
first portion and a second portion; running said drain pump during
the acceleration step of the spin cycle for about the acceleration
step time interval; operating said drain pump at a first duty cycle
during the dwell step of the spin cycle for about the first portion
of the dwell step time interval; and working said drain pump at a
second duty cycle during the dwell step of the spin cycle for about
the second portion of the dwell step time interval.
12. The washing machine appliance of claim 11, wherein the
acceleration step and the dwell step of the spin cycle are
substantially sequential.
13. The washing machine appliance of claim 11, wherein the first
duty cycle is greater than the second duty cycle.
14. The washing machine appliance of claim 11, wherein the spin
cycle of the washing machine appliance further comprises an
additional acceleration step in which said motor accelerates said
wash basket from about the second angular velocity to a third
angular velocity, the third angular velocity being different than
the second angular velocity, the additional acceleration step of
the spin cycle performed during an additional acceleration step
time interval, and wherein the spin cycle of the washing machine
appliance also further comprises an additional dwell step in which
said motor rotates said wash basket at about the third angular
velocity, the additional dwell step of the spin cycle performed
during an additional dwell step time interval, the additional dwell
step time interval having a first portion and a second portion,
said processing device further configured for: running said drain
pump during the additional acceleration step of the spin cycle for
about the additional acceleration step time interval; operating
said drain pump at a third duty cycle during the additional dwell
step of the spin cycle for about the first portion of the
additional dwell step time interval; and working said drain pump at
a fourth duty cycle during the additional dwell step of the spin
cycle for about the second portion of the additional dwell step
time interval.
15. The washing machine appliance of claim 14, wherein the
acceleration step, the dwell step, the additional acceleration
step, and the additional dwell step of the spin cycle are
substantially sequential.
16. The washing machine appliance of claim 14, wherein the first
duty cycle and the third duty cycle are about equal, and the second
duty cycle and the fourth duty cycle are about equal.
17. The washing machine appliance of claim 14, wherein the third
duty cycle is greater than the fourth duty cycle.
18. The washing machine appliance of claim 11, wherein the spin
cycle of the washing machine appliance further comprises a brake
step in which the wash basket accelerates from about the second
angular velocity to about a zero angular velocity, the zero angular
velocity being different than the second angular velocity, said
processing device further configured for: utilizing said drain pump
during the brake step of the spin cycle for a predetermined period
of time.
19. The washing machine appliance of claim 18, wherein the
predetermined period of time is about thirty seconds.
20. The washing machine appliance of claim 11, wherein the second
angular velocity is between about eighty radians per second and
about one hundred and ten radians per second.
Description
FIELD OF THE INVENTION
[0001] The present subject matter relates generally to washing
machine appliances and methods for operating the same.
BACKGROUND OF THE INVENTION
[0002] A washing machine appliance generally includes a cabinet
with a wash tub mounted therein. The wash tub includes a sump that
collects liquid disposed within wash tub. A wash basket is
rotatably mounted within the wash tub and can receive articles for
washing. The washing machine appliance also includes a drain pump
that is in fluid communication with the sump of the wash tub. The
drain pump can selectively direct a flow of liquid out of the sump,
e.g., in order to drain the sump of liquid.
[0003] During a wash cycle of the washing machine appliance, wash
liquid, e.g., detergent, fabric softener, bleach, and/or water, can
fill the wash tub and be applied to articles within the wash
basket. Such wash liquid can assist with cleaning of the articles,
e.g., as the articles are agitated during the wash cycle. After the
wash cycle, the washing machine appliance can rinse the wash fluid
from the articles, e.g., using fresh water. After the rinse cycle,
the washing machine appliance can initiate one or more spin cycles
to remove liquids from the articles. During the spin cycles, the
wash basket can be rotated at relatively high speeds to wring
liquid from the articles. Such liquid can flow out of the articles
and collect within the sump of the wash tub. In turn, the drain
pump can be utilized to remove the liquid from the wash tub.
[0004] Presently, during the spin cycle, the drain pump is
activated continuously or for a predetermined time interval in
order to insure that liquid does not overflow the sump and
negatively affect washing machine performance. For example, if
liquid overflows the sump, such liquid can impact a bottom of the
wash basket and hinder rotation of the wash basket. Similarly, the
liquid can generate foam during rotation of wash basket, and such
foam can increase drag on the wash basket. However, despite the
potential negative effects of permitting liquid to fill the wash
tub's sump, running the drain pump continuously or for a
predetermined time interval during the spin cycle is often unduly
conservative. In particular, an extraction rate of liquid from the
articles with the wash basket (e.g., due to rotation of the wash
basket) is generally much less than a drain rate of the drain pump.
Thus, operating the drain pump in the manner described above is
unnecessary to insure that liquid does not overflow the sump.
[0005] Further, operating the drain pump in the manner described
above can lead to unnecessary wear and tear on the drain pump. In
addition, operating the drain pump in such a manner can lead to
overheating of the drain pump due to a concentration of thermal
energy within the drain pump. Thus, the drain pump can require a
thermally suitable material for construction, e.g., copper rather
than a potentially cheaper though less thermally suitable material
such as aluminum.
[0006] Accordingly, a method for operating a washing machine
appliance such that a drain pump removes liquid from a sump of the
appliance in a more efficient manner would be useful. In
particular, a method for operating a washing machine appliance such
that a drain rate of the washing machine appliance is about equal
to an extraction rate of the washing machine appliance would be
useful. Also, a method for operating a washing machine appliance
such that potential overheating of the drain pump is reduced would
be useful.
BRIEF DESCRIPTION OF THE INVENTION
[0007] The present subject matter provides a washing machine
appliance with a wash basket rotatably mounted within a wash tub
and a drain pump for removing liquid from the wash tub. During a
spin cycle of the washing machine appliance, the drain pump may be
activated during an acceleration portion of the spin cycle.
Further, the drain pump may be operated at a first duty cycle for a
first portion of a dwell step of the spin cycle and at a second
duty cycle for a second portion of the dwell step of the spin
cycle. Additional aspects and advantages of the invention will be
set forth in part in the following description, or may be apparent
from the description, or may be learned through practice of the
invention.
[0008] In a first exemplary embodiment, a method for operating a
washing machine appliance is provided. The washing machine
appliance has a cabinet with a wash tub mounted therein. The
washing machine appliance also has a wash basket positioned within
the wash tub. The wash basket is configured for receipt of articles
for washing and is mounted for rotation relative to the cabinet.
The method includes initiating a spin cycle of the washing machine
appliance. The spin cycle includes an acceleration step in which
the wash basket accelerates from a first angular velocity to a
second angular velocity. The first angular velocity is different
than the second angular velocity. The acceleration step of the spin
cycle is performed during an acceleration step time interval. The
spin cycle also includes a dwell step in which the wash basket
rotates at about the second angular velocity. The dwell step of the
spin cycle is performed during a dwell step time interval. The
dwell step time interval includes a first portion and a second
portion. The method further includes: running the drain pump of the
washing machine appliance during the acceleration step of the spin
cycle for about the acceleration step time interval; operating the
drain pump of the washing machine appliance at a first duty cycle
during the dwell step of the spin cycle for about the first portion
of the dwell step time interval; and working the drain pump of the
washing machine appliance at a second duty cycle during the dwell
step of the spin cycle for about the second portion of the dwell
step time interval.
[0009] In a second exemplary embodiment, a washing machine
appliance is provided. The washing machine appliance includes a
cabinet and a wash tub mounted within the cabinet. The wash tub is
configured for holding liquid during operation of the washing
machine appliance. A wash basket is rotatably mounted within the
wash tub. The wash basket is configured for receipt of articles for
washing. A motor is in mechanical communication with the wash
basket such that the motor selectively rotates the wash basket. A
drain pump is in fluid communication with the wash tub. The drain
pump is configured for selectively urging liquid out of the wash
tub. The washing machine appliance also includes a processing
device in communication with the drain pump and the motor. The
processing device is configured for initiating the motor during a
spin cycle of the washing machine appliance. The spin cycle
includes an acceleration step in which the motor accelerates the
wash basket from a first angular velocity to a second angular
velocity. The first angular velocity is different than the second
angular velocity. The acceleration step of the spin cycle is
performed during an acceleration step time interval. The spin cycle
also includes a dwell step in which the motor rotates the wash
basket at about the second angular velocity. The dwell step of the
spin cycle is performed during a dwell step time interval. The
dwell step time interval has a first portion and a second portion.
The processing device is further configured for: running the drain
pump during the acceleration step of the spin cycle for about the
acceleration step time interval; operating the drain pump at a
first duty cycle during the dwell step of the spin cycle for about
the first portion of the dwell step time interval; and working the
drain pump at a second duty cycle during the dwell step of the spin
cycle for about the second portion of the dwell step time
interval.
[0010] These and other features, aspects and advantages of the
present invention will become better understood with reference to
the following description and appended claims. The accompanying
drawings, which are incorporated in and constitute a part of this
specification, illustrate embodiments of the invention and,
together with the description, serve to explain the principles of
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] A full and enabling disclosure of the present invention,
including the best mode thereof, directed to one of ordinary skill
in the art, is set forth in the specification, which makes
reference to the appended figures, in which:
[0012] FIG. 1 provides a perspective view of a washing machine
appliance according to an exemplary embodiment of the present
subject matter. A portion of a cabinet of the washing machine
appliance has been removed to reveal certain interior components of
the washing machine appliance.
[0013] FIG. 2 is a partial, section view of the washing machine
appliance of FIG. 1.
[0014] FIG. 3 illustrates plots of rotational speed of a wash
basket of a washing machine appliance in rotations per minute
versus time in seconds and weight of the wash basket in pounds
versus time in seconds during a spin cycle of the washing machine
appliance.
[0015] FIG. 4 illustrates a method for operating a washing machine
appliance according to an exemplary embodiment of the present
subject matter.
[0016] FIG. 5 illustrates another method for operating a washing
machine appliance according to an additional exemplary embodiment
of the present subject matter.
DETAILED DESCRIPTION
[0017] Reference now will be made in detail to embodiments of the
invention, one or more examples of which are illustrated in the
drawings. Each example is provided by way of explanation of the
invention, not limitation of the invention. In fact, it will be
apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing
from the scope or spirit of the invention. For instance, features
illustrated or described as part of one embodiment can be used with
another embodiment to yield a still further embodiment. Thus, it is
intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and
their equivalents.
[0018] FIG. 1 is a perspective view partially broken away of a
vertical axis washing machine appliance 50 according to an
exemplary embodiment of the present subject matter. While discussed
in the context of washing machine appliance 50, using the teachings
disclosed herein, it should be understood that washing machine
appliance 50 is provided by way of example only. Other washing
machine appliances having different appearances and different
features may also be utilized with the present subject matter as
well, e.g., horizontal axis washing machine appliances.
[0019] Washing machine appliance 50 includes a cabinet 52 and a
cover 54. A backsplash 56 extends from cover 54, and a control
panel 58 including a plurality of input selectors 60 is coupled to
backsplash 56. Control panel 58 and input selectors 60 collectively
form a user interface input for operator selection of washing
machine cycles and features, and in one embodiment, a display 61
indicates selected features, a countdown timer, and/or other items
of interest to machine users. A lid 62 is mounted to cover 54 and
is rotatable about a hinge (not shown) between an open position
(not shown) facilitating access to a wash tub 64 located within
cabinet 52, and a closed position (shown in FIG. 1) forming an
enclosure over wash tub 64.
[0020] Wash tub 64 includes a bottom wall 66 and a sidewall 68, and
a wash basket 70 that is rotatably mounted within wash tub 64. A
drain pump or pump assembly 72 is located beneath tub 64 and wash
basket 70 for gravity assisted flow when draining tub 64. Pump
assembly 72 includes a pump 74 and a motor 76. A pump inlet hose 80
extends from a wash tub outlet 82 in tub bottom wall 66 to a pump
inlet 84, and a pump outlet hose 86 extends from a pump outlet 88
to an outlet 90 and ultimately to a building plumbing system
discharge line (not shown, e.g., a sewer or septic line) in fluid
communication with outlet 90.
[0021] FIG. 2 is a front sectional view of washing machine
appliance 50 including wash basket 70 movably disposed and
rotatably mounted in wash tub 64 in a spaced apart relationship
from tub sidewall 68 and the tub bottom 66. Wash basket 70 includes
an opening for receiving wash fluid and articles for washing, e.g.,
clothing, bedding, etc., therein. Wash basket 70 defines a
plurality of perforations 71 to facilitate fluid communication
between an interior of wash basket 70 and wash tub 64.
[0022] An agitation element 92, such as a vane agitator, impeller,
auger, or oscillatory basket mechanism, or some combination thereof
is disposed in wash basket 70 to impart an oscillatory motion to
articles and liquid in wash basket 70. In different embodiments,
agitation element 92 includes a single action element (i.e.,
oscillatory only), double action (oscillatory movement at one end,
single direction rotation at the other end) or triple action
(oscillatory movement plus single direction rotation at one end,
singe direction rotation at the other end). As illustrated in FIG.
2, agitation element 92 is oriented to rotate about a vertical axis
A. Wash basket 70 and agitator 92 are driven by pancake motor 94.
As motor output shaft 98 is rotated, wash basket 70 and agitation
element 92 are operated for rotatable movement within wash tub
64.
[0023] Washing machine appliance 50 may also include a brake
assembly (not shown) selectively applied or released for
respectively maintaining wash basket 70 in a stationary position
within wash tub 64 or for allowing wash basket 70 to spin within
wash tub 64. Pump assembly 72 is selectively activated, e.g., to
remove liquid from wash basket 70 and wash tub 64 through drain
outlet 90 during appropriate points in washing cycles as washing
machine appliance 50 is used.
[0024] Operation of washing machine appliance 50 is controlled by a
controller or processing device 63 (FIG. 1) that is operatively
coupled to the user interface input located on backsplash 56 for
user manipulation to select washing machine cycles and features. In
response to user manipulation of the user interface input,
controller 63 operates the various components of washing machine
appliance 50 to execute selected machine cycles and features as
described in greater detail below.
[0025] Controller 63 may include a memory and microprocessor, such
as a general or special purpose microprocessor operable to execute
programming instructions or micro-control code. The memory may
represent random access memory such as DRAM, or read only memory
such as ROM or FLASH. In one exemplary embodiment, the processor
executes programming instructions stored in memory. The memory may
be a separate component from the processor or may be included
onboard within the processor.
[0026] Controller 63 may be positioned in a variety of locations
throughout washing machine appliance 50. In the illustrated
exemplary embodiment, controller 63 is located within backsplash 56
as shown. In such an embodiment, input/output ("I/O") signals may
be routed between controller 63 and various operational components
of washing machine appliance 50, e.g., pump assembly 72 and/or
pancake motor 94, along wiring harnesses (not shown). Controller 63
is also operatively coupled to control panel 58 and input selectors
60 through which a user may select various operational features and
modes and monitor progress of washing machine appliance 50. In one
exemplary embodiment, input selectors 60 may represent a general
purpose I/O ("GPIO") device or functional block. Control panel 58
and input selectors 60 may be in communication with controller 63
via one or more signal lines or shared communication busses.
[0027] As an example, laundry items can be loaded into wash basket
70, and washing operation can be initiated through operator
manipulation of control input selectors 60. Wash tub 64 is filled
with water and mixed with detergent to form a wash fluid, and
contents of the wash basket 70 are agitated with agitation element
92 for cleansing of laundry items in wash basket 70. More
specifically, agitation element 92 is moved back and forth in an
oscillatory back and forth motion.
[0028] After the agitation phase of the wash cycle is completed,
wash tub 64 is drained with pump assembly 72. Laundry items are
then rinsed and portions of the cycle repeated, including the
agitation phase, depending on the particulars of the wash cycle
selected by a user. One or more spin cycles may also be performed.
In particular, a spin cycle may be applied after the wash cycle
and/or after the rinse cycle in order to wring wash fluid from the
articles being washed. During a spin cycle, wash basket 70 is
rotated at relatively high speeds by pancake motor 94 such that
wash fluid exits the wash basket 70 at an extraction rate. As wash
fluid exits wash basket 70, e.g., through plurality of perforations
71, such wash fluid enters wash tub 64 where pump assembly 72 is
utilized to remove such wash fluid from washing machine appliance
50 at a drain rate.
[0029] As will be understood by those skilled in the art, the
extraction rate of wash fluid exiting the wash basket 70 during the
spin cycle is a function of many variables. For example, the
extraction rate can vary as a function of the volume of wash fluid
contained within articles in wash basket 70 and the angular
velocity of the wash basket 70. Similarly, the drain rate of pump
assembly 72 is also a function of many variables. For example, the
drain rate can vary as a function of pump assembly design, customer
drain height, and any degradation of the building plumbing system
discharge line over time. In order for washing machine appliance 50
to operate more efficiently, the drain rate of pump assembly 72 can
be matched to the extraction rate of washing machine appliance 50
during spin cycle, e.g., utilizing the methods described below.
[0030] FIG. 3 illustrates plots of rotational speed of wash basket
70 in rotations per minute versus time in seconds and weight of
wash basket 70 in pounds versus time in seconds during an exemplary
spin cycle of the washing machine appliance 50. Such spin cycle may
be performed after a wash cycle of washing machine appliance 50
and/or after a rinse cycle of washing machine appliance 50 in order
to wring liquid from articles disposed within wash basket 70. The
spin cycle shown in FIG. 3 is provided by way of example only and
is not intended to limit the present subject matter in any regard.
Thus, washing machine appliance 50 may operate with alternative
exemplary spin cycles with similar or different characteristics
from the exemplary spin cycle shown in FIG. 3.
[0031] As may be seen in FIG. 3, the exemplary spin cycle has four
distinct portions: a low speed (LS) portion; a moderate speed (MS)
portion; a high speed (HS) portion; and a brake portion. During the
low speed portion of the spin cycle, the wash basket 70 first
accelerates from about zero rotations per minute to about
one-hundred and fifty rotations per minute during a low speed
acceleration step, shown as A.sub.ls in FIG. 3. The wash basket 70
rotates at about one-hundred and fifty rotations per minute during
a low speed dwell step that includes a first portion and a second
portion, shown as D.sub.ls,1 and D.sub.ls,2 in FIG. 3.
[0032] During the low speed portion of the spin cycle, wash basket
70 rotates at a relatively slow speed, e.g., to evenly distribute
articles within the wash basket 70 and/or to permit wash fluid to
exit wash basket 70 prior to rotating wash basket 70 at a greater
velocity as will be understood by those skilled in the art. During,
the low speed dwell step the wash basket 70 may be rotated by
pancake motor 94 at any suitable angular velocity, e.g., between
about ten radians per second and about twenty radians per
second.
[0033] The low speed portion of the spin cycle is performed during
a low speed time interval. In FIG. 3, the low speed time interval
is about three minutes. However, low speed time interval may be any
other suitable time interval in alternative exemplary
embodiments.
[0034] During the moderate speed portion of the spin cycle, the
wash basket 70 accelerates from about one-hundred and fifty
rotations per minute rotations per minute to about four hundred
rotations per minute during a moderate speed acceleration step,
shown as A.sub.ms in FIG. 3. The wash basket 70 rotates at about
four hundred rotations per minute during a moderate speed dwell
step that includes a first portion and a second portion, shown as
D.sub.ms,1 and D.sub.ms,2 in FIG. 3.
[0035] During the moderate speed portion of the spin cycle, wash
basket 70 rotates at a relatively moderate speed, e.g., to permit
detection of imbalances in distribution of articles within the wash
basket 70 as is well understood by those skilled in the art. During
the moderate speed dwell step the wash basket 70 may be rotated by
pancake motor 94 at any suitable angular velocity, e.g., between
about thirty radians per second and about fifty radians per
second.
[0036] The moderate speed portion of the spin cycle is performed
during a moderate speed time interval. In FIG. 3, the moderate
speed time interval is about one minute. However, moderate speed
time interval may be any other suitable time interval in
alternative exemplary embodiments.
[0037] During the high speed portion of the spin cycle, the wash
basket 70 accelerates from about four hundred rotations per minute
rotations per minute to about nine hundred rotations per minute
during a high speed acceleration step, shown as A.sub.hs in FIG. 3.
The wash basket 70 rotates at about nine hundred rotations per
minute during a high speed dwell step that includes a first portion
and a second portion, shown as D.sub.hs,1 and D.sub.hs,2 in FIG.
3.
[0038] During the high speed portion of the spin cycle, wash basket
70 rotates at a relatively high speed compared to the lower
rotational speeds described above, e.g., to extract or wring wash
liquid from articles within the wash basket 70 as is well
understood by those skilled in the art. During the high speed dwell
step the wash basket 70 may be rotated by pancake motor 94 at any
suitable angular velocity, e.g., between about eighty radians per
second and about one hundred and ten radians per second.
[0039] The high speed portion of the spin cycle is performed during
a high speed time interval. In FIG. 3, the high speed time interval
is about five and a half minutes. However, high speed time interval
may be any other suitable time interval in alternative exemplary
embodiments.
[0040] During the brake portion of the spin cycle, the wash basket
70 negatively accelerates from about nine hundred rotations per
minute rotations per minute to zero rotations per minute during a
brake step shown as B in FIG. 3. During the brake portion of the
spin cycle, rotation of wash basket 70 is stopped, e.g., to
terminate the spin cycle as is well understood by those skilled in
the art.
[0041] The brake portion of the spin cycle is performed during a
brake time interval. In FIG. 3, the brake time interval is about
half a minute. However, brake time interval may be any other
suitable time interval in alternative exemplary embodiments.
[0042] As discussed above, the spin cycle shown in FIG. 3 is
provided by way of example only. Thus, washing machine appliance 50
may operate with an alternative exemplary spin cycle that includes
any suitable combination of the low speed portion, the moderate
speed portion, and the high speed portion and may also include
additional portions not shown in FIG. 3.
[0043] As may be seen in FIG. 3, the weight of wash basket 70
decreases continuously during the spin cycle. However, the weight
of wash basket 70 decreases at a higher rate during the
acceleration portions A.sub.ls, A.sub.ms, and A.sub.hs of the spin
cycle relative to the dwell steps D.sub.ls,1, D.sub.ls,2,
D.sub.ms,1, D.sub.ms,2, D.sub.hs,1, and D.sub.hs,2 of the spin
cycle. Similarly, the weight of wash basket 70 decreases at a
higher rate during the first portion of the dwell step D.sub.ls,1,
D.sub.ms,1, and D.sub.hs,1 relative to the second portion of the
dwell step D.sub.ls,2, D.sub.ms,2, and D.sub.hs,2.
[0044] As will be understood by those skilled in the art, wash
basket 70 decreases in weight during the spin cycle as wash liquid
is extracted from articles within wash basket 70 and such wash
fluid exits wash basket 70. Thus, a higher rate of weight change
for wash basket 70 can correlate to an increased extraction rate
for wash fluid exiting wash basket 70. Conversely, a lower rate of
weight change for wash basket 70 can correlate to a decreased
extraction rate for wash fluid exiting wash basket 70. As may be
seen in FIG. 3, the extraction rate is greatest during the
acceleration portions A.sub.ls, A.sub.ms, and A.sub.hs of the spin
cycle and smallest during the second portion of the dwell step
D.sub.ls,2, D.sub.ms,2, and D.sub.hs,2.
[0045] As discussed above, wash fluid collects in wash tab 64 upon
exiting the wash basket 70, and pump assembly 72 can be utilized to
remove such wash fluid from washing machine appliance 50. However,
pump assembly 72 generally has a drain rate that is greater than
the extraction rate when pump assembly 72 is operated continuously.
Thus, operating pump assembly 72 continuously during the spin cycle
can be inefficient. As discussed above, the drain rate of pump
assembly 72 can be matched to the extraction rate of washing
machine appliance 50 during a spin cycle utilizing the methods
described below.
[0046] FIG. 4 illustrates a method 400 for operating washing
machine appliance 50 according to an exemplary embodiment of the
present subject matter. Utilizing method 400, washing machine
appliance 50 may operate more efficiently. For example, operation
of pump assembly 72 may be optimized so that pump assembly 72 does
not run unnecessarily. Method 400 may be implemented or carried out
by controller 63.
[0047] At step 410, controller 63 initiates a spin cycle of washing
machine appliance 50, e.g., the spin cycle descried in FIG. 3. The
spin cycle includes an acceleration step (e.g., A.sub.ls, A.sub.ms,
or A.sub.hs) in which wash basket 70 accelerates from a first
angular velocity (e.g., about zero radians per second) to a second
angular velocity (e.g., about fifteen radians per second). The
first angular velocity is different than the second angular
velocity. The acceleration step of the spin cycle is performed
during an acceleration step time interval. The spin cycle also
includes a dwell step in which the wash basket 70 rotates at about
the second angular velocity. The acceleration step and the dwell
step of the spin cycle may be substantially sequential. The dwell
step of the spin cycle is performed during a dwell step time
interval. The dwell step time interval includes a first portion
(e.g., D.sub.ls,1, D.sub.ms,1, or D.sub.hs,1) and a second portion
(e.g., D.sub.ls,2, D.sub.ms,2, or D.sub.hs,2).
[0048] At step 420, controller 63 runs pump assembly 72 of washing
machine appliance 50 during the acceleration step of the spin cycle
for about the acceleration step time interval. As described above,
the extraction rate for wash liquid from wash basket 70 can be
greatest during the acceleration step of the spin cycle. Thus,
running pump assembly 72 during the acceleration step can insure
that pump assembly 72 is removing wash liquid from wash tub 64 when
the extraction rate is greatest.
[0049] At step 430, controller 63 operates pump assembly 72 at a
first duty cycle during the dwell step of the spin cycle for about
the first portion of the dwell step time interval. Conversely, at
step 440, controller 63 works pump assembly 72 at a second duty
cycle during the dwell step of the spin cycle for about the second
portion of the dwell step time interval. The first and second duty
cycles can be different. Thus, pump assembly 72 can operate at two
distinct duty cycles during the dwell step of the spin cycle.
[0050] The term "duty cycle" corresponds to proportion, e.g., a
percentage or ratio, of time that pump assembly 72 spends in an
active state relative to a total time period under consideration.
As an example, a 60% duty cycle corresponds to controller 63
running pump assembly 72 for 60% of the relevant time period and
deactivating pump assembly 72 for 40% of the relevant time
period.
[0051] As discussed above, the extraction can be smallest during
the second portion of the dwell step. Conversely, the extraction
rate can be larger during the first portion of the dwell step
relative to the second portion of the dwell step. Thus, the first
and second duty cycles of the pump assembly 72 can be selected to
match the extraction rates for wash basket 70 during both the first
portion of the dwell step and the second portion of the dwell step.
Thus, operation of pump assembly 72 can be regulated with
controller 63 and operated at the first and second duty cycles to
more closely match the drain rate of pump assembly 72 to the
extraction rate of wash basket 70.
[0052] In additional exemplary embodiments, the spin cycle may
further include an additional acceleration step in which wash
basket 70 accelerates from about the second angular velocity to
about a third angular velocity (e.g., about ninety-five radians per
second). The third angular velocity is different than the second
angular velocity. The additional acceleration step of the spin
cycle is performed during an additional acceleration step time
interval. The spin cycle may also further include an additional
dwell step in which wash basket 70 rotates at about the third
angular velocity. The additional dwell step of the spin cycle is
performed during an additional dwell step time interval. The
additional dwell step time interval having a first portion and a
second portion.
[0053] In such embodiments, method 400 may further include the
steps of: (1) running pump assembly 72 during the additional
acceleration step of the spin cycle for about the additional
acceleration step time interval; (2) operating pump assembly 72 at
a third duty cycle during the additional dwell step of the spin
cycle for about the first portion of the additional dwell step time
interval; (3) and working pump assembly 72 at a fourth duty cycle
during the additional dwell step of the spin cycle for about the
second portion of the additional dwell step time interval. The
third duty cycle may be greater than the fourth duty cycle. The
acceleration step, the dwell step, the additional acceleration
step, and the additional dwell step of the spin cycle may be
substantially sequential. In addition, the first duty cycle may be
equal to or different from the third duty cycle. Similarly, the
second duty cycle may be equal to or different form the fourth duty
cycle.
[0054] In a further exemplary embodiment, the spin cycle further
includes a brake step in which the wash basket 70 accelerates
negatively from about the second angular velocity to about a zero
angular velocity. The zero angular velocity is different than the
second angular velocity. The method 400 may further include the
step of utilizing pump assembly 72 during the brake step of the
spin cycle for a predetermined period of time. The predetermined
period of time may be any suitable period of time, e.g., about
thirty seconds.
[0055] FIG. 5 illustrates a method 500 for operating washing
machine appliance 50 according to an additional exemplary
embodiment of the present subject matter. Utilizing method 500,
washing machine appliance 50 may operate more efficiently. For
example, operation of pump assembly 72 may be optimized so that
pump assembly 72 does not run unnecessarily during a spin cycle.
Method 500 may be implemented or carried out by controller 63.
[0056] At step 510, a spin cycle of washing machine appliance 50 is
initiated, e.g., by controller 63. At steps 520, 540, and 550,
controller 63 determines a stage of the spin cycle in which the
washing machine appliance 50 is operating. In particular, at step
520, controller 63 determines whether the spin cycle is in an
acceleration step. Similarly, at step 540, controller 63 determines
whether the spin cycle is in a dwell step. Also, at step 550,
controller 63 determines whether the spin cycle is in a brake
step.
[0057] If controller 63 determines that the spin cycle is in the
acceleration step at step 520, controller 63 runs pump assembly 72.
Conversely, if controller 63 determines that the spin cycle is in
the dwell step at step 540, controller 63 then determines if the
spin cycle is in a first portion at step 542. If controller 63
determines that the spin cycle is in the first portion, controller
63 operates pump assembly 72 at a first duty cycle. Conversely, if
controller 63 determines that the spin cycle is in not the first
portion, controller 63 operates pump assembly 72 at a second duty
cycle. At step 550, if controller 63 determines that the spin cycle
is in the brake step, controller 63 operates pump assembly 72 for a
predetermined time interval. At 530, controller 63 determines
whether the spin cycle is complete.
[0058] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they include structural elements that do not
differ from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *