U.S. patent application number 14/468889 was filed with the patent office on 2016-03-03 for dishwasher appliances and methods for operating appliances.
The applicant listed for this patent is General Electric Company. Invention is credited to Craig Curtis, Mark Thomas Fryman, Gregory Owen Miller.
Application Number | 20160058263 14/468889 |
Document ID | / |
Family ID | 55401104 |
Filed Date | 2016-03-03 |
United States Patent
Application |
20160058263 |
Kind Code |
A1 |
Miller; Gregory Owen ; et
al. |
March 3, 2016 |
DISHWASHER APPLIANCES AND METHODS FOR OPERATING APPLIANCES
Abstract
Dishwasher appliances and methods for operating appliances are
provided. A method includes activating a drain pump to operate at a
first speed, and ascertaining a dry drain status for the drain pump
after a first speed drain time. The method further includes
performing a deactivation routine when the dry drain status is
positive, the deactivation routine comprising deactivating the
drain pump. The method further includes performing a secondary
drain routine when the dry drain status is negative, the secondary
drain routine comprising activating the drain pump to operate at a
second speed, the second speed greater than the first speed.
Inventors: |
Miller; Gregory Owen;
(Louisville, KY) ; Curtis; Craig; (Crestwood,
KY) ; Fryman; Mark Thomas; (Louisville, KY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
55401104 |
Appl. No.: |
14/468889 |
Filed: |
August 26, 2014 |
Current U.S.
Class: |
134/18 ;
134/56D |
Current CPC
Class: |
A47L 2501/05 20130101;
A47L 15/4225 20130101; A47L 15/0052 20130101; A47L 15/0031
20130101; A47L 2401/08 20130101 |
International
Class: |
A47L 15/00 20060101
A47L015/00; A47L 15/42 20060101 A47L015/42 |
Claims
1. A method for operating an appliance, the method comprising:
activating a drain pump to operate at a first speed; ascertaining a
dry drain status for the drain pump after a first speed drain time;
performing a deactivation routine when the dry drain status is
positive, the deactivation routine comprising deactivating the
drain pump; and performing a secondary drain routine when the dry
drain status is negative, the secondary drain routine comprising
activating the drain pump to operate at a second speed, the second
speed greater than the first speed.
2. The method of claim 1, wherein the deactivation routine further
comprises continuing operation of the drain pump at the first speed
for a first speed extend time, and wherein deactivating the drain
pump occurs after continuing operation of the drain pump at the
first speed for the first speed extend time.
3. The method of claim 1, wherein the secondary drain routine
further comprises ascertaining the dry drain status for the drain
pump after a second speed drain time.
4. The method of claim 3, wherein the secondary drain routine
further comprises performing a secondary deactivation routine when
the dry drain status is positive, the secondary deactivation
routine comprising deactivating the drain pump.
5. The method of claim 4, wherein the secondary deactivation
routine further comprises continuing operation of the drain pump at
the second speed for a second speed extend time, and wherein
deactivating the drain pump occurs after continuing operation of
the drain pump at the second speed for the second speed extend
time.
6. The method of claim 3, wherein the secondary drain routine
further comprises continuing operation of the drain pump at the
second speed when the dry drain status is negative and repeating
the step of ascertaining the dry drain status for the drain pump
after a second speed drain time.
7. The method of claim 6, wherein the secondary drain routine
further comprises tallying consecutive occurrences of the dry drain
status being negative.
8. The method of claim 7, wherein the secondary drain routine
further comprises disabling activation of the drain pump at the
first speed when the tally of consecutive occurrences is greater
than or equal to a consecutive occurrence threshold.
9. The method of claim 6, wherein the secondary drain routine
further comprises resetting the tally of consecutive occurrences
when a positive dry drain status occurs.
10. A dishwasher appliance, comprising: a tub that defines a wash
chamber for receipt of articles for washing; a sump for collecting
fluid from the wash chamber; a fluid circulation assembly in fluid
communication with the sump, the fluid circulation assembly
comprising a drain pump; and a control unit in communication with
the drain pump, the control unit operable for: activating the drain
pump to operate at a first speed; ascertaining a dry drain status
for the drain pump after a first speed drain time; performing a
deactivation routine when the dry drain status is positive, the
deactivation routine comprising deactivating the drain pump; and
performing a secondary drain routine when the dry drain status is
negative, the secondary drain routine comprising activating the
drain pump to operate at a second speed, the second speed greater
than the first speed.
11. The dishwasher appliance of claim 10, wherein the deactivation
routine further comprises continuing operation of the drain pump at
the first speed for a first speed extend time, and wherein
deactivating the drain pump occurs after continuing operation of
the drain pump at the first speed for the first speed extend
time.
12. The dishwasher appliance of claim 10, wherein the secondary
drain routine further comprises ascertaining the dry drain status
for the drain pump after a second speed drain time.
13. The dishwasher appliance of claim 12, wherein the secondary
drain routine further comprises performing a secondary deactivation
routine when the dry drain status is positive, the secondary
deactivation routine comprising deactivating the drain pump.
14. The dishwasher appliance of claim 13, wherein the secondary
deactivation routine further comprises continuing operation of the
drain pump at the second speed for a second speed extend time, and
wherein deactivating the drain pump occurs after continuing
operation of the drain pump at the second speed for the second
speed extend time.
15. The dishwasher appliance of claim 12, wherein the secondary
drain routine further comprises continuing operation of the drain
pump at the second speed when the dry drain status is negative and
repeating the step of ascertaining the dry drain status for the
drain pump after a second speed drain time.
16. The dishwasher appliance of claim 15, wherein the secondary
drain routine further comprises tallying consecutive occurrences of
the dry drain status being negative.
17. The dishwasher appliance of claim 16, wherein the secondary
drain routine further comprises disabling activation of the drain
pump at the first speed when the tally of consecutive occurrences
is greater than or equal to a consecutive occurrence threshold.
18. The dishwasher appliance of claim 15, wherein the secondary
drain routine further comprises resetting the tally of consecutive
occurrences when a positive dry drain status occurs.
19. The dishwasher appliance of claim 10, wherein the drain pump is
a two-speed drain pump.
20. The dishwasher appliance of claim 10, wherein the fluid
circulation assembly further comprises a wash pump.
Description
FIELD OF THE INVENTION
[0001] The present disclosure relates generally to dishwasher
appliances, and more specifically to methods and apparatus for
operating drain pumps of dishwasher appliances which balance
efficient draining requirements with quiet operation desires.
BACKGROUND OF THE INVENTION
[0002] Dishwasher appliances generally include one or more pumps,
such as a wash pump and/or drain pump. The wash pump can circulate
liquid throughout a wash chamber of the dishwasher, for washing or
rinsing items contained therein. The drain pump can remove liquid
from the wash chamber of the appliance. For example, liquid can
collect in a sump disposed at a bottom of the wash chamber during
operation of the dishwasher appliance and the drain pump can be
operated to urge such liquid from the sump to a drain where the
liquid can flow out of the appliance.
[0003] In general, it is considered desirable for a dishwasher
appliance to operate quietly. The noise level generated by the
pumps is critical to such quiet operation. However, many dishwasher
appliances are installed into environments which, for example, have
undesirable draining conditions. It is thus critical that the drain
pump in particular operate at a sufficient level to facilitate
complete draining, even in such undesirable situations. This level,
however, can result in louder than desired noise generation.
[0004] Accordingly, improved dishwasher appliances and methods for
operating dishwasher appliances are desired. In particular,
dishwasher appliances and associated methods which balance desires
for quiet operation with complete draining requirements would be
advantageous.
BRIEF DESCRIPTION OF THE INVENTION
[0005] 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.
[0006] In accordance with one embodiment, a method for operating an
appliance is provided. The method includes activating a drain pump
to operate at a first speed, and ascertaining a dry drain status
for the drain pump after a first speed drain time. The method
further includes performing a deactivation routine when the dry
drain status is positive, the deactivation routine comprising
deactivating the drain pump. The method further includes performing
a secondary drain routine when the dry drain status is negative,
the secondary drain routine comprising activating the drain pump to
operate at a second speed, the second speed greater than the first
speed.
[0007] In accordance with another embodiment, a dishwasher
appliance is provided. The dishwasher appliance includes a tub that
defines a wash chamber for receipt of articles for washing, and a
sump for collecting fluid from the wash chamber. The dishwasher
appliance further includes a fluid circulation assembly in fluid
communication with the sump, the fluid circulation assembly
comprising a drain pump, and a control unit in communication with
the drain pump. The control unit is operable for activating the
drain pump to operate at a first speed, and ascertaining a dry
drain status for the drain pump after a first speed drain time. The
control unit is further operable for performing a deactivation
routine when the dry drain status is positive, the deactivation
routine comprising deactivating the drain pump. The control unit is
further operable for performing a secondary drain routine when the
dry drain status is negative, the secondary drain routine
comprising activating the drain pump to operate at a second speed,
the second speed greater than the first speed.
[0008] 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
[0009] 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:
[0010] FIG. 1 provides a side cutaway view of a dishwasher
appliance in accordance with one embodiment of the present
disclosure;
[0011] FIG. 2 provides a schematic view of a fluid circulation
assembly for a dishwasher appliance in accordance with one
embodiment of the present disclosure; and
[0012] FIG. 3 provides a flow chart illustrating a method for
operating an appliance in accordance with one embodiment of the
present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0013] 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.
[0014] FIG. 1 depicts an exemplary dishwasher appliance 100
according to an exemplary embodiment of the present disclosure.
However, it should be understood that the systems and methods
disclosed herein are not limited to use with dishwashers as
described herein, and rather that any suitable dishwasher appliance
is within the scope and spirit of the present disclosure. Further,
the present disclosure is not limited to dishwashers. Rather, use
with other suitable appliances, such as washing machine appliances,
is within the scope and spirit of the present disclosure.
[0015] The dishwasher appliance 100 can include a cabinet 102
having a tub 104 therein that defines a wash chamber 106. The tub
104 can include a front opening (not shown in FIG. 1) and a door
120 hinged at its bottom 122 for movement between a normally closed
vertical position wherein the wash chamber 106 is sealed shut for
washing operation, and a horizontal open position for loading and
unloading of dishwasher contents. Upper and lower guide rails 124,
126 can be mounted on tub side walls 128 and can accommodate upper
and lower roller-equipped rack assemblies 130, 132,
respectively.
[0016] A lower spray-arm-assembly 144 can be rotatably mounted
within a lower region 146 of the wash chamber 106 and above tub
sump portion 142 so as to rotate in relatively close proximity to
the lower rack assembly 132. A mid-level spray-arm assembly 148 can
be located in an upper region of the wash chamber 106 and can be
located in close proximity to the upper rack 130 and at a
sufficient height above lower rack 132 to accommodate larger items,
such as a dish or platter. In a further embodiment, an upper spray
assembly can be located above the upper rack assembly 130 at a
sufficient height to accommodate taller items in the upper rack
assembly 130.
[0017] The lower and mid-level spray-arm assemblies 144, 148 and
the upper spray arm assembly can be fed by a fluid circulation
assembly for circulating water and dishwasher fluid in the tub 104.
The fluid circulation assembly can be located in a machinery
compartment 140 located below the bottom sump portion 142 of the
tub 104, as generally recognized in the art.
[0018] Operation of the dishwasher 100 can be regulated by a
control unit 137 which is operatively coupled to a user interface
or input 136 for user manipulation to select dishwasher machine
cycles and features. In response to user manipulation of the user
interface 136, the control unit 137 can operate the various
components of the dishwasher appliance 100 and execute selected
machine cycles and features. The control unit may include one or
more memory devices and one or more microprocessors, such as
general or special purpose microprocessors operable to execute
programming instructions or micro-control code associated with a
particular cycle of the dishwasher appliance 100. The memory may
represent random access memory such as DRAM, or read only memory
such as ROM or FLASH. In one 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.
[0019] In one embodiment, the user interface 136 can represent a
general purpose I/O ("GPIO") device or functional block. In another
embodiment, the user interface 136 can include input components,
such as one or more of a variety of electrical, mechanical or
electro-mechanical input devices including rotary dials, push
buttons, and touch pads. The user interface 136 can include a
display component, such as a digital or analog display device
designed to provide operational feedback to a user.
[0020] The control unit 137 can be positioned in a variety of
locations throughout dishwasher 100. In the illustrated embodiment,
the control unit 137 is located within a control panel area of door
120 as shown. In such an embodiment, input/output ("I/O") signals
can be routed between the control system and various operational
components of dishwasher 100 along wiring harnesses that can be
routed through the bottom 122 of door 120.
[0021] Again, it should be appreciated that the method disclosed
herein is not limited to any particular style, model, or other
configuration of dishwasher, and that the embodiment depicted in
FIG. 1 is for illustrative purposes only. Further, the present
disclosure is not specifically limited to dishwashers, but can be
implemented with respect to other appliances as well, including
washing machine appliances.
[0022] FIG. 2 depicts an exemplary fluid circulation assembly 170
of the exemplary dishwasher of FIG. 1 according to an exemplary
embodiment of the present disclosure. Although one exemplary
embodiment of fluid circulation assembly 170 operable in accordance
with aspects of the disclosure is shown, it is contemplated that
other fluid circulation assembly configurations may similarly be
utilized without departing from the spirit and scope of the
invention.
[0023] Fluid circulation assembly 170 can include a wash pump 172
and a drain pump 174, both in fluid communication with sump 150.
Additionally, drain pump 174 can be in fluid communication with an
external drain 173 to discharge used wash liquid, e.g., to a sewer
or septic system (not shown). Further, wash pump 172 can be in
fluid communication with lower spray arm assembly 144 and conduit
154 which extends to a back wall 156 of wash chamber 106, and
upward along back wall 156 for feeding wash liquid to mid-level
spray arm assembly 148 (FIG. 1) and the upper spray arm assembly.
This configuration also applies to a drawer-type of dishwasher, as
mentioned above.
[0024] As wash liquid is pumped through lower spray arm assembly
144, and further delivered to mid-level spray arm assembly 148 and
the upper spray arm assembly (not shown), washing sprays can be
generated in wash chamber 106, and wash liquid can collect in sump
150. Sump 150 can include a cover to prevent larger objects from
entering sump 150, such as a piece of silverware or another
dishwasher item that is dropped beneath lower rack 132. A coarse
filter and a fine filter (not shown) can be located adjacent sump
150 to filter wash liquid for sediment and particles of
predetermined sizes before flowing into sump 150. Sump 150 can be
filled with water through an inlet port 175 which outlets into wash
chamber 106, as described in greater detail below.
[0025] A water supply 200 can be configured with inlet port 175 for
supplying wash liquid to wash chamber 106. Water supply 200 can
provide hot water only, cold water only, or either selectively as
desired. As depicted, water supply 200 can have a hot water input
204 that receives hot water from an external source, such as a hot
water heater and a cold water input 206 that receives cold water
from an external source. It should be understood that the term
"water supply" is used herein to encompass any manner or
combination of valves, lines or tubing, housing, and the like, and
may simply comprise a conventional hot or cold water
connection.
[0026] As shown in FIG. 2, a drain valve 186 can be established in
flow communication with sump 150 and can open or close flow
communication between sump 150 and a drain pump inlet 188. Drain
pump 174 can be in flow communication with drain pump inlet 188 and
can include an electric motor for pumping fluid at inlet 188 to an
external drain system via drain 173. In one embodiment, when drain
pump 174 is operating, a negative pressure can be created in drain
pump inlet 188 and drain valve 186 is opened, allowing fluid in
sump 150 to flow into fluid pump inlet 188 and be discharged from
fluid circulation assembly 170 via external drain 173.
[0027] Alternatively, drain and wash pumps 172 and 174 can be
connected directly to the side or the bottom of sump 150, and drain
and wash pumps 172, 174 can each include their own valving
replacing drain valve 186. Other fluid circulation systems are
possible as well, drawing fluid from sump 150 and providing fluid
as desired within wash chamber 106 or draining fluid out of
appliance 100.
[0028] In addition, fluid circulation assembly 170 can include one
or more heating elements for heating water within the dishwasher.
Generally, the heating elements can be used to heat water for use
by wash pump 172 for one or more wash or rinse cycles in which the
contents of the dishwasher are subjected to the heated water. In
particular, in some embodiments, the one or more heating elements
can be included internally within wash pump 172.
[0029] As shown in FIG. 2 and as discussed below, control unit 137
can communicate with and is operable to control the operation of
wash pump 172, drain pump 174, drain valve 186, and water supply
200.
[0030] As discussed above, dishwasher appliances 100 and associated
methods that provide a balance between quiet operation and complete
drainage are desired. Accordingly, and referring now to FIG. 3, the
present disclosure is further directed to methods 300 for operating
appliances, such as dishwasher appliances 100, washing machine
appliances, and other suitable appliances, which advantageously
provide such balance. Additionally, dishwasher appliances 100 which
include control units 137 that facilitate such balance are
advantageously provided. It should be understood that control unit
137 may in exemplary embodiments be operable to perform the various
method steps as disclosed herein.
[0031] Advantageously such methods 300 and appliances utilize drain
pumps 174 which can be activated to operate at multiple speeds. In
other words, the motor of such drain pumps 174 may operate at
multiple speeds. In some embodiments, for example, a drain pump 174
may be operable at only two speeds. In other embodiments drain pump
174 may be operable at more than two speeds. In general, it is
understood that the speed at which a pump operates is proportional
to the power output of the pump. For example, a higher speed
results in a greater power output. In the context of a drain pump
174, a higher speed can thus result in more efficient and/or
complete draining Higher speeds would thus be desirable in
environments which have undesirable draining conditions, caused for
example, by blockages, small drain pipes, etc. Of course, a speed
increase can also result in an increase in the noise produced by
the pump when operating. The present methods and appliances
advantageously balance these concerns.
[0032] Method 300 may thus include, for example, the step 310 of
activating the drain pump 174 to operate at a first speed 312. The
drain pump 174 may be activated as desired and as generally
understood to facilitate draining of liquid from the dishwasher
appliance 100 during appliance 100 operation. The first speed 312
may advantageously be a low speed, such as a speed lower than a
second speed as discussed herein. Advantageously, operation at such
low speed may provide generally desirable quiet operation.
[0033] Method 300 may further include, for example, the step 320 of
ascertaining a dry drain status 322 for the drain pump 174 after a
first speed drain time 324. In exemplary embodiments, the drain
time 324 is a predetermined time period that is for example
programmed into the control unit 137. The drain time 324 may begin,
for example, when the drain pump 174 is activated in accordance
with step 310, and may be a time period for draining before the dry
drain status 322 is ascertained. The drain time 324 may or may not
include pauses of various lengths of time to facilitate draining.
Ascertaining the dry drain status 322 includes determining whether
the draining operation of the drain pump 174 is complete by
determining whether the drain pump 174 is generally dry. If the
drain pump 174 is generally dry, the dry drain status 322 may be
positive. If the drain pump 174 is not generally dry, and draining
is thus still required, the dry drain status 322 may be
negative.
[0034] Ascertainment of the dry drain status 322 may be
accomplished in accordance with a variety of methods and/or
apparatus, and is generally understood in the art. For example, in
some embodiments, a pump inverter current may be monitored. For
each instance in which the pump transitions from a wet state to a
dry state or cavitation, the inverter current may demonstrate a
detectable reduction in magnitude. Details of suitable methods and
apparatus for such detection are provided in, for example, U.S.
patent application Ser. No. 13/937,493 filed on Jul. 9, 2013 and
entitled "Systems and Methods for Detecting Appliance Pump
Cavitation or Dry State", which is incorporated by reference in its
entirety herein. Such reduction in magnitude may for example be
utilized to detect a positive dry drain status 322. If, for
example, when step 320 occurs it is ascertained that no reduction
in magnitude has occurred during the first speed drain time 324,
the dry drain status 322 may be negative. If, on the other hand,
when step 320 occurs it is ascertained that a reduction in
magnitude has occurred during the first speed drain time 324, the
dry drain status 322 may be positive.
[0035] It should be understood that the present disclosure is not
limited to such embodiments for ascertainment of the dry drain
status 322, and rather that any suitable methods or apparatus are
within the scope and spirit of the present disclosure.
[0036] In some cases, the dry drain status 322 may be positive.
Accordingly, method 300 may further include the step 330 of
performing a deactivation routine when the dry drain status 322 is
positive. The deactivation routine may include, for example, the
step 334 of deactivating the drain pump 174. In some embodiments,
such deactivation may be performed immediately upon ascertainment
that the dry drain status 322 is positive. In other embodiments,
the deactivation routine may further include, for example, the step
336 of continuing operation of the drain pump 174 at the first
speed 312 for a first speed extend time 338. In exemplary
embodiments, the extend time 338 is a predetermined time period
that is for example programmed into the control unit 137. Such
first speed extend time 338 may be a time period that provides an
additional delay before deactivating the drain pump 174, as a
backup to ensure that the drain pump 174 is sufficiently dry before
it is deactivated. The step 334 may thus in these embodiments occur
after the step 336.
[0037] When the dry drain status 322 is positive as discussed
above, this generally indicates that the first speed 312 is
currently sufficient for draining purposes. Further, as discussed,
such operation is advantageously at a relatively low noise level,
such that drainage and noise concerns are balanced.
[0038] In other cases, the dry drain status 322 may be negative.
Accordingly, method 300 may further include the step 340 of
performing a secondary drain routine when the dry drain status 322
is negative. The secondary drain routine may include, for example,
the step 350 of activating the drain pump 174 to operate at a
second speed 352. The second speed may be greater than the first
speed 312. Such second speed 352 may thus cause the drain pump 174
to produce relatively more noise than the first speed 312. However,
the negative dry drain status 322 in these cases indicates that
increased power output from the drain pump 174 may be necessary for
drainage to be completed. Accordingly, activation at this point at
the second speed 352 may balance drainage and noise concerns, which
the drainage concerns at this point taking precedence.
[0039] The secondary drain routine may additionally include other
steps which may serve to further evaluate and balance drainage and
noise concerns. For example, the secondary drain routine may
further include the step 360 of ascertaining the dry drain status
322 for the drain pump 174 after a second speed drain time 364. In
exemplary embodiments, the drain time 364 is a predetermined time
period that is for example programmed into the control unit 137.
The drain time 364 may begin, for example, when the drain pump 174
is activated in accordance with step 350, and may be a time period
for draining before the dry drain status 322 is ascertained. The
drain time 364 may or may not include pauses of various lengths of
time to facilitate draining.
[0040] In some cases, the dry drain status 322 may be positive.
Accordingly, method 300 may further include the step 370 of
performing a secondary deactivation routine when the dry drain
status 322 is positive. The secondary deactivation routine may
include, for example, the step 374 of deactivating the drain pump
174. In some embodiments, such deactivation may be performed
immediately upon ascertainment that the dry drain status 322 is
positive. In other embodiments, the deactivation routine may
further include, for example, the step 376 of continuing operation
of the drain pump 174 at the second speed 352 for a second speed
extend time 378. In exemplary embodiments, the extend time 378 is a
predetermined time period that is for example programmed into the
control unit 137. Such second speed extend time 378 may be a time
period that provides an additional delay before deactivating the
drain pump 174, as a backup to ensure that the drain pump 174 is
sufficiently dry before it is deactivated. The step 374 may thus in
these embodiments occur after the step 376.
[0041] In other cases, the dry drain status 322 may be negative.
Accordingly, method 300 may further include the step 380 of
continuing operation of the drain pump 174 at the second speed 352
when the dry drain status 322 is negative and repeating the
ascertaining step 360. Accordingly, after an additional second
speed drain time 364, the dry drain status 322 for the drain pump
174 may again be ascertained. Step 380 may additionally then be
repeated as required upon repeating step 360 if the dry drain
status 322 is negative. When the dry drain status 322 is positive,
such repetition may be discontinued, because step 370 (and
associated sub-steps) may occur.
[0042] In some embodiments, the secondary drain routine may further
include the step 400 of tallying consecutive occurrences 402 of the
dry drain status 322 being negative. For example, a first
occurrence may be tallied after step 320 when the dry drain status
322 is negative and step 340 generally occurs. Consecutive
occurrences after this first occurrence may be tallied after step
360 when the dry drain status 322 is negative and step 380 occurs,
such that step 360 is repeated.
[0043] Further, the secondary drain routine may include the step
410 of disabling activation of the drain pump 174 at the first
speed 312 when the tally of consecutive occurrences 402 is greater
than or equal to a consecutive occurrence threshold 412. In
exemplary embodiments, the consecutive occurrence threshold 412 is
a predetermined number that is for example programmed into the
control unit 137. When the tally of consecutive occurrences 402
meets or exceeds the threshold 412, this generally indicates a
drainage issue, such as a permanently slow drainage environment. In
these cases, activation of the drain pump 174 at the first speed
312 is disabled, because the need for complete draining in an
efficient manner takes precedence over the desire for quiet
operation.
[0044] Secondary drain routine may further additionally include,
for example, the step 420 of resetting the tally of consecutive
occurrences 402 when a positive dry drain status 322 occurs. In
exemplary embodiments, such resetting step 420 may only occur
before step 410 occurs. Accordingly, an intervening positive dry
drain status 322 may reset the tally of consecutive occurrences 402
to zero or a lesser number in the tally, such that the tally begins
anew from zero or a new, lesser tally value upon the next operation
of the drain pump 174 in accordance with the present disclosure.
This allows operation of the drain pump 174 at the first speed 312
to be utilized again to attempt complete drainage, thus
advantageously allowing quiet operation when complete drainage does
occur before the consecutive occurrence threshold 412 is met to
indicate the need for higher speed, higher power drainage and
resulting increased noise.
[0045] Accordingly, the present disclosure advantageously provides
methods 300 and dishwasher appliances which balance the needs for
complete and efficient drainage with the desire for quiet operation
in a variety of drainage scenarios.
[0046] 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.
* * * * *