Note: Descriptions are shown in the official language in which they were submitted.
CA 02815970 2013-05-16
SUB-02635-US-NP
LAUNDRY TREATING APPLIANCE AND METHOD OF DETECTING OVERSUDS
BACKGROUND OF THE INVENTION
100011 Laundry treating appliances, such as clothes washers, typically
include a tub in which
is mounted a rotatable wash basket which receives laundry for treatment
according to a cycle of
operation. In a typical wash cycle, the laundry is often treated with a
laundry detergent or other
wash aid that includes surfactants. These surfactants may mix with liquid on
the laundry and in
the tub to generate suds. In some cases, the generation of suds may generate a
suds lock
condition and interfere with the rotation of the wash basket, thereby limiting
the speed at which
the wash basket may be rotated.
BRIEF DESCRIPTION
[0002] A method for detecting an oversuds condition that may lead to a suds
lock condition
in a laundry treating appliance having a tub defining an interior, with a wash
basket rotatably
mounted within the interior and at least partially defining a treating chamber
for receiving
laundry for treatment in accordance with a cycle of operation using a wash
liquid. The method
comprises determining a baseline fill level in the treating chamber prior to
introducing wash
liquid into the treating chamber in the cycle of operation; sampling fill
levels of the wash liquid
in the treating chamber during a wash phase of the cycle of operation while
wash liquid is being
drained from the treating chamber; comparing each sampled fill level to the
baseline fill level
and determining a difference; continuing to sample fill levels in the treating
chamber for a
predetermined period after the difference equals zero; identifying a minimum
fill level in the
treating chamber for the predetermined period; sampling a final fill level
after the predetermined
period; calculating a difference between the minimum fill level and the final
fill level; and
identifying an over suds condition that can lead to a suds lock condition if
the difference exceeds
a predetermined threshold.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] FIG. 1 is a schematic cross-sectional view of a laundry treating
appliance according
to one embodiment of the invention.
[0004] FIG. 2 is a schematic view of a controller of the laundry treating
appliance of FIG. 1.
1
CA 02815970 2013-05-16
= SUB-02635-US-NP
[0005] FIG. 3 is a flowchart illustrating a method for detecting an over
suds condition
according to an embodiment of the invention.
[0006] FIG. 4 is a graphical representation of a treating chamber fill
level profile according
to an embodiment of the invention.
DESCRIPTION
[0007] Referring now to the figures, FIG. 1 is a schematic view of an
exemplary laundry
treating appliance 10 in the form of a washing machine according to one
embodiment of the
invention. While the laundry treating appliance 10 is illustrated as a
vertical axis, top-fill
washing machine, the invention may have applicability in other laundry
treating appliances, such
as a horizontal washing machine, combination laundry treating appliance and
dryer, an extractor,
a non-aqueous laundry treating appliance, and a tumbling or stationary
refreshing/revitalizing
machine, for example.
[0008] The washing machine 10 may include a cabinet or housing 12 and an
imperforate tub
14 that defines an interior 15 of the washing machine 10. A sump 16 may be in
fluid
communication with the interior 15 of the tub 14. A drum or perforated wash
basket 18 may be
located within and rotatable relative to the interior 15 of the tub 14 and may
define a laundry
treating chamber 19 for receiving a laundry load. The wash basket 18 may
include a plurality of
perforations or apertures (not shown) such that liquid supplied to the wash
basket 18 may flow
through the perforations to the tub 14. An agitator or clothes mover 20 may be
located within
the laundry treating chamber 19 and rotatable relative to and/or with the wash
basket 18.
[0009] The wash basket 18 and/or the clothes mover 20 may be driven by an
electrical motor
22, which may or may not include a gear case, operably connected to the wash
basket 18 and/or
the clothes mover 20. The clothes mover 20 may be commonly oscillated or
rotated about its
axis of rotation during a cycle of operation in order to produce high water
turbulence effective to
treat the fabric load contained within the laundry treating chamber 19. The
wash basket 18 may
be rotated at high speed to centrifugally extract liquid from the fabric load
and to discharge it
from the wash basket 18. The top of the housing 12 may include a selectively
openable lid 24 to
provide access into the laundry treating chamber 19 through the open top of
the wash basket 18.
[0010] Still referring to Figure 1, a spraying system 30 may be provided to
spray liquid, such
as water or a combination of water and one or more treating agents into the
open top of the wash
basket 18 and onto laundry placed within the laundry treating chamber 19. Non-
limiting
2
CA 02815970 2013-05-16
SUB-02635-US-NP
examples of treating chemistries that may be dispensed by the dispensing
system during a cycle
of operation include one or more of the following: water, surfactants,
enzymes, fragrances,
stiffness/sizing agents, wrinkle releasers/reducers, softeners, antistatic or
electrostatic agents,
stain repellants, water repellants, energy reduction/extraction aids,
antibacterial agents, medicinal
agents, vitamins, moisturizers, shrinkage inhibitors, and color fidelity
agents, and combinations
thereof.
[0011] The spraying system 30 may be configured to supply water directly
from a household
water supply 32 and/or from the tub 14 and spray it onto the laundry through a
sprayer 33. The
spraying system 30 may also be configured to recirculate wash water from the
tub 14, including
the sump 16, and spray it onto the laundry. The spraying system 30 can also
include additional
sprayers and other components to supply liquid to one or more additional
locations, such as a
portion of the interior 15 between the wash basket 18 and the tub 14, an
exterior surface of the
wash basket 18, an interior surface of the wash basket 18 and an internal
surface of the tub 14.
The nature of the spraying system is not germane to the invention, and thus
any suitable spraying
system may be used with the laundry treating appliance 10.
[0012] A pump 34 may be housed below the tub 14. The pump 34 may have an
inlet fluidly
coupled to the sump 16 and an outlet configured to fluidly couple to either or
both a household
drain 36 or a recirculation conduit 38. In this configuration, the pump 34 may
be used to drain or
recirculate liquid in the sump 16, which is initially sprayed into the wash
basket 18, flows
through the wash basket 18, and then into the sump 16. Alternatively, two
separate pumps may
be used instead of the single pump as previously described.
[0013] As used herein, the term wash liquid refers to a combination of
water and one or more
treating agents capable of generating suds. The terms rinse liquid and rinse
water are
interchangeable and refer to water supplied from the household water supply 32
that has not been
mixed with a treating agent prior to being applied to the laundry. The terms
recirculated liquid
and recirculated water refer to water or a combination of water and one or
more treating agents
that is pumped from the sump 16 and re-applied to the laundry, with or without
the addition of
additional rinse liquid from the household water supply 32.
[0014] The washing machine 10 also includes a control system for
controlling the operation
of the washing machine 10 to implement one or more cycles of operation. The
control system
may include a controller 60 located within the cabinet 12 and a user interface
62 that is operably
3
CA 02815970 2013-05-16
SUB-02635-US-NP
coupled with the controller 60. The user interface 62 may include one or more
knobs, dials,
switches, displays, touch screens and the like for communicating with the
user, such as to receive
input and provide output. The user may enter different types of information
including, without
limitation, cycle selection and cycle parameters, such as cycle options.
[0015] The controller 60 may include the machine controller and any
additional controllers
provided for controlling any of the components of the washing machine 10. For
example, the
controller 60 may include the machine controller and a motor controller. Many
known types of
controllers may be used for the controller 60. The specific type of controller
is not germane to
the invention. It is contemplated that the controller 60 is a microprocessor-
based controller that
implements control software and sends/receives one or more electrical signals
to/from each of
the various working components to effect the control software. As an example,
proportional
control (P), proportional integral control (PI), and proportional derivative
control (PD), or a
combination thereof, a proportional integral derivative control (PID control),
may be used to
control the various components.
[0016] As illustrated in Figure 2, the controller 60 may be provided with a
memory 70 and a
central processing unit (CPU) 72. The memory 70 may be used for storing the
control software
that is executed by the CPU 72 in implementing a cycle of operation using the
washing machine
and any additional software. Examples, without limitation, of cycles of
operation include:
wash, heavy duty wash, delicate wash, quick wash, pre-wash, refresh, rinse
only, and timed
wash. A common wash cycle includes a wash phase, a rinse phase, and a spin
extraction phase.
Other phases for cycles of operation include, but are not limited to,
intermediate extraction
phases, such as between the wash and rinse phases, and a pre-wash phase
preceding the wash
phase, and some cycles of operation include only a select one or more of these
exemplary phases.
[0017] The memory 70 may also be used to store information, such as a
database or table,
and to store data received from one or more components of the washing machine
10 that may be
communicably coupled with the controller 60. The database or table may be used
to store the
various operating parameters for the one or more cycles of operation,
including factory default
values for the operating parameters and any adjustments to them by the control
system or by user
input.
[0018] The controller 60 may be operably coupled with one or more
components of the
washing machine 10 for communicating with and controlling the operation of the
component to
4
CA 02815970 2013-05-16
SUB-02635-US-NP
complete a cycle of operation. For example, the controller 60 may be operably
coupled with the
motor 22, the pump 34, and the spraying system 30 to control the operation of
these and other
components to implement one or more of the cycles of operation.
[0019] The previously described washing machine 10 may be used to implement
one or more
embodiments of the invention. The embodiments of the method of the invention
may be used to
control the operation of the washing machine 10 to detect the formation of
surfactant foam or
suds in the tub 14 to mitigate a potential suds lock condition. As used
herein, mitigating a suds
lock condition may include decreasing the formation of suds and/or removing
suds from the tub
14 such that a suds lock condition is avoided or the effect of the suds on the
tub 14 and wash
basket 18 is decreased.
[0020] A typical wash cycle includes a wash phase in which a wash liquid,
e.g., a mixture of
water and surfactants (and optionally other treating agents), is applied to
the laundry, a rinse
phase in which the wash liquid is removed from the laundry by rinsing the
laundry with rinse
liquid, and a spin extraction phase in which at least a portion of the rinse
liquid is extracted from
the laundry by spinning the laundry at high speeds. A suds lock condition
occurs when the wash
liquid forms suds and the suds interact with the wash basket 18 and tub 14,
causing excess
frictional drag between the wash basket 18 and the tub 14. The excess
frictional drag may inhibit
the wash basket 18 from accelerating to a desired wash basket rotation speed,
such as a final or
spin extraction rotation speed in which the laundry is rotated at high speeds
to extract liquid from
the laundry. The methods described herein may be used to detect an over suds
condition that can
lead to a suds lock condition prior to the rinse phase.
[0021] Referring now to Figure 3, a flowchart of a method 100 for detecting
an over suds
condition during a cycle of operation is illustrated. The method 100 may be
used during a wash
cycle or any other cycle of operation in which wash liquid has been applied to
the laundry. The
method 100 may be implemented as part of a wash or rinse phase of a wash cycle
or may be
implemented as a separate phase. The sequence of steps depicted for this
method is for
illustrative purposes only, and is not meant to limit the method in any way as
it is understood that
the steps may proceed in a different logical order or additional or
intervening steps may be
included without detracting from the invention.
[0022] The method 100 starts with assuming that a cycle of operation in
which a wash liquid
is applied to the laundry in the treating chamber 19, such as a wash cycle,
has not yet been
CA 02815970 2013-05-16
SUB-02635-US-NP
=
implemented. At 102, the controller 60 implementing the method 100 may measure
a baseline
fill level in the treating chamber 19. The baseline fill level is the initial
level of liquid in the
treating chamber 19 before wash liquid is introduced for the cycle of
operation. The controller 60
may monitor the fill level of the wash liquid in the treating chamber 19 by
sampling a sensor
such as a pressure transducer (not shown) located in the treating chamber 19.
An example
pressure transducer and sampling rate that may be used is the Panasonic
ADP51B62 sampled
once every 63 ms. Other fluid level sensing technologies and sampling rates
may be used
depending upon the implementation.
[00231 At 104, the fill and wash steps of the cycle of operation may be
completed. During
these steps, wash liquid may be introduced in the treating chamber 19.
[00241 At 106, the pump 34 may drain the wash liquid from the treating
chamber 19. The
operation of draining the treating chamber 19 may continue until the processor
60 determines the
treating chamber 19 is empty. The controller 60 may determine that the
treating chamber 19 is
empty by sampling the fill level of the treating chamber 19 as the wash liquid
is being drained
and comparing the sampled fill level to the baseline fill level from 102. When
the sampled fill
level is less than or equal to the baseline fill level from 102, the
controller 60 may consider the
treating chamber 19 to be empty.
[0025] Once the difference between the sampled fill level and the baseline
fill level is zero,
the controller 60 may start a timer at 108 for a predetermined period. The
predetermined time
period may be determined by the particular physical characteristics of an
implementation of the
washer. A predetermined time period of 60 seconds may be used but other
predetermined time
periods are possible depending upon the specific implementation.
[0026] For the duration of the predetermined time period, the controller 60
may sample the
fill level of the treating chamber 19 and store the minimum fill level. The
controller 60 may
make a check to determine if the predetermined time period has expired at 110,
and if it has not,
may determine if the currently sampled fill level is less than the current
minimum fill level for
the predetermined time period. If the currently sampled fill level is less
than the current
minimum fill level for the predetermined time period, then the controller 60
may update the
stored minimum fill level for the predetermined time period to be the
currently sampled fill level
at 112. By repeating the steps at 110 and 112 until the expiration of the
predetermined time
period at 110, the controller 60 may determine the minimum fill level in the
treating chamber 19
6
CA 02815970 2013-05-16
"
SUB-02635-US-NP
for the predetermined time period. After the predetermined time period has
expired, the
controller 60 may stop draining the treatment chamber 19 at 114 and sample a
final fill level at
116.
[0027] At 118, the controller 60 may calculate the difference between the
minimum fill level
and the final fill level by subtracting the minimum fill level during the
predetermined time period
from the final fill level. If the difference is greater than a predetermined
threshold as calculated
at 120, the controller 60 may identify at 122 that a suds lock condition may
occur due to an
excessive amount of suds. The predetermined threshold may be determined by the
particular
physical characteristics of an implementation of the washer.
[0028] The controller 60 may then take action at 124 to mitigate or avoid a
suds lock
condition. For example, upon the identification of a potential suds lock
condition, the controller
60 may rotate the wash basket in a progressive rinse phase of the wash cycle.
The controller 60
may take other actions to mitigate the potential suds lock condition depending
upon the specific
implementation.
[0029] If, at 120, the difference is not greater than a predetermined
threshold, the controller
60 may not identify a potential suds lock condition at 126. The controller 60
may then continue
to a normal phase of the cycle of operation at 128. For example, the
controller 60 may rotate the
wash basket in a deep rinse phase of the wash cycle.
[0030] Referring now to Figure 4, an exemplary treating chamber fill level
profile 200 is
illustrated. The treating chamber fill level profile 200 illustrates the fill
level of the treating
chamber 19 during implementation of the method 100 of Figure 3 in the course
of a cycle of
operation. The treating chamber fill level profile 200 may not be indicative
of actual data, but is
included for the purposes of illustration.
[0031] Figure 4 illustrates the drain phase of a wash cycle 200 where
excessive suds that
may lead to a suds lock condition may be present. The profile shown is digital
counts of a
pressure sensor indicating fill level of a treating chamber 19 versus time in
seconds. The fill level
is shown to be decreasing at 202 as the treating chamber 19 drains. At 204,
the controller 60 may
determine the treating chamber is empty and records a baseline fill level. The
controller 60 may
then continue to sample the fill level for a predetermined period of time and
record the minimum
fill level at 206. When the predetermined period of time ends, the controller
60 may sample a
final fill level and compare to the minimum fill level. If the controller 60
determines the
7
CA 02815970 2013-05-16
SUB-02635-US-NP
minimum fill level at 206 is below the final fill level by a predetermined
threshold, it may
identify excessive suds that may lead to an suds lock condition and take
appropriate action to
mitigate or avoid a suds lock condition.
[0032] The methods described herein may be used to detect and mitigate the
formation of a
suds lock condition in a washing machine. Excess suds in a washing machine may
increase the
frictional drag between the wash basket and the tub, which may result in the
wash basket not
reaching a desired rotational speed or may require additional energy to reach
the desired rotation
speed, which may increase energy costs during the cycle. During a spin
extraction phase, the
wash basket is rotated at high speeds to remove liquid from the laundry for
subsequent treatment
or drying. If the wash basket cannot be rotated at the desired spin extraction
speed due to a suds
lock condition, it may take longer to extract liquid from the laundry, which
may provide an
undesirable lengthening of the cycle, or the laundry may maintain more liquid
at the end of the
cycle, which may be undesirable to the user. The methods described herein may
be used to
identify a potential suds lock condition before it occurs and decrease the
interaction between the
tub and the wash basket during rotation of the wash basket.
[0033] To the extent not already described, the different features and
structures of the various
embodiments may be used in combination with each other as desired. That one
feature may not
be illustrated in all of the embodiments is not meant to be construed that it
cannot be, but is done
for brevity of description. Thus, the various features of the different
embodiments may be mixed
and matched as desired to form new embodiments, whether or not the new
embodiments are
expressly described.
[0034] While the invention has been specifically described in connection
with certain
specific embodiments thereof, it is to be understood that this is by way of
illustration and not of
limitation. Reasonable variation and modification are possible within the
scope of the forgoing
disclosure and drawings without departing from the spirit of the invention
which is defined in the
appended claims.
8
