U.S. patent application number 14/013497 was filed with the patent office on 2015-03-05 for dryer appliance and a method for operating the same.
This patent application is currently assigned to General Electric Company. The applicant listed for this patent is General Electric Company. Invention is credited to Richard Dustin Henderson, Ionelia Silvia Prajescu.
Application Number | 20150059200 14/013497 |
Document ID | / |
Family ID | 52581177 |
Filed Date | 2015-03-05 |
United States Patent
Application |
20150059200 |
Kind Code |
A1 |
Prajescu; Ionelia Silvia ;
et al. |
March 5, 2015 |
DRYER APPLIANCE AND A METHOD FOR OPERATING THE SAME
Abstract
The present subject matter provides a dryer appliance and a
method for operating a dryer appliance. The method includes
monitoring a first temperature sensor of the dryer appliance in
order to determine a number of cycles of the first temperature
sensor. If the number of cycles of the heating element exceeds a
threshold number, a temperature set point of a second temperature
sensor of the dryer appliance is reduced. The method can assist
with reducing or avoiding excessive cycling of the first
temperature sensor.
Inventors: |
Prajescu; Ionelia Silvia;
(Louisville, KY) ; Henderson; Richard Dustin;
(Louisville, KY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Assignee: |
General Electric Company
Schenectady
NY
|
Family ID: |
52581177 |
Appl. No.: |
14/013497 |
Filed: |
August 29, 2013 |
Current U.S.
Class: |
34/282 ;
34/524 |
Current CPC
Class: |
D06F 2103/08 20200201;
D06F 2105/28 20200201; D06F 58/38 20200201; D06F 58/30
20200201 |
Class at
Publication: |
34/282 ;
34/524 |
International
Class: |
D06F 58/28 20060101
D06F058/28 |
Claims
1. A method for operating a dryer appliance, comprising: initiating
a drying cycle of the dryer appliance in order to dry articles
within a drum of the dryer appliance; monitoring a first
temperature sensor of the dryer appliance in order to determine a
number of cycles of the first temperature sensor during the drying
cycle of the dryer appliance; reducing a temperature set point of a
second temperature sensor of the dryer appliance if the number of
cycles of the first temperature sensor exceeds a threshold number
during said step of monitoring.
2. The method of claim 1, wherein the first temperature sensor
comprises a bimetallic switch.
3. The method of claim 1, wherein the second temperature sensor
comprises a thermistor.
4. The method of claim 1, wherein the threshold number is greater
than fifteen.
5. The method of claim 4, wherein the threshold number is about
twenty.
6. A dryer appliance, comprising: a cabinet; a drum rotatably
mounted within the cabinet, the drum defining a chamber for receipt
of articles for drying; a motor configured for selectively rotating
the drum within the cabinet; a heating assembly configured for
directing a flow of heated fluid into the chamber of the drum, the
heating assembly comprising a housing; a heating element disposed
within the housing; a duct extending between the housing of the
heating assembly and the drum, the duct having an outlet positioned
at the chamber of the drum; a first temperature sensor positioned
at the housing; and a second temperature sensor positioned at the
outlet of the duct; a controller in communication with the motor,
the heating element and the first and second temperature sensors,
the controller configured for setting a temperature set point of
the second temperature sensor to a first temperature set point;
determining if an operating condition of the dryer appliance is a
restricted condition; adjusting the temperature set point of the
second temperature sensor to a second temperature set point if the
operating condition is the restricted condition at said step of
determining; monitoring the first temperature sensor in order to
determine a number of cycles of the first temperature sensor; and
changing the temperature set point of the second temperature sensor
to a third temperature set point if the number of cycles of the
first temperature sensor exceeds a threshold number during said
step of monitoring.
7. The appliance of claim 6, wherein the first temperature sensor
comprises a bimetallic switch.
8. The appliance of claim 6, wherein the second temperature sensor
comprises a thermistor.
9. The appliance of claim 6, wherein the first temperature set
point is greater than the second temperature set point.
10. The appliance of claim 9, wherein the second temperature set
point is greater than the third temperature set point.
11. The appliance of claim 6, wherein the third temperature set
point is selected to avoid cycling the first temperature sensor
after said step of changing.
12. The appliance of claim 11, wherein the third temperature set
point is less than about three hundred degrees Fahrenheit.
13. The appliance of claim 11, wherein the third temperature set
point is about two hundred and forty degrees Fahrenheit.
14. The appliance of claim 6, wherein the threshold number is
greater than fifteen.
15. The appliance of claim 14, wherein the threshold number is
about twenty.
16. The appliance of claim 6, wherein said step of determining
comprises establishing a first derivative of temperature
measurements from the second temperature sensor, the restricted
condition corresponding to the condition of the dryer appliance
when the first derivative of temperature measurements from the
second temperature sensor exceeds a threshold value.
17. A method for operating a dryer appliance, comprising: setting a
temperature set point of a thermistor of the dryer appliance to a
first temperature set point; determining if an operating condition
of the dryer appliance is a restricted condition; adjusting the
temperature set point of the thermistor to a second temperature set
point if the operating condition is the restricted condition at
said step of determining; monitoring a thermostat of the dryer
appliance in order to determine a number of cycles of the
thermostat; and changing the temperature set point of the
thermistor to a third temperature set point if the number of cycles
of the thermostat exceeds a threshold number during said step of
monitoring.
18. The method of claim 17, wherein the threshold number is greater
than fifteen.
19. The method of claim 17, wherein the third temperature set point
is selected to avoid cycling the thermostat after said step of
changing.
20. The method of claim 17, wherein the first temperature set point
is greater than the second temperature set point, and the second
temperature set point is greater than the third temperature set
point.
Description
FIELD OF THE INVENTION
[0001] The present subject matter relates generally to dryer
appliances and methods for operating dryer appliances.
BACKGROUND OF THE INVENTION
[0002] Certain dryer appliances include a cabinet with a drum
rotatably mounted therein. A heating assembly, such as an electric
resistance heating element or a gas burner, can supply heated air
to a chamber of the drum. For example, certain dryer appliances
include a duct mounted to a back wall of the drum. The duct can
direct heated air from the heating assembly into the chamber of the
drum during operation of the dryer appliance. The duct generally
includes an inlet that receives heated air from the heating
assembly and a plurality of outlets for directing such heated air
into the chamber of the drum. Such heated air can assist with
drying articles located within the drum's chamber.
[0003] Heated air exiting the duct's outlets is preferably
maintained below a certain threshold temperature, e.g., to avoid
damaging articles that are drying within the chamber of the drum
and other overheating problems. Certain dryer appliances are
equipped with temperature sensors for monitoring the temperature of
heated air entering the drum's chamber. If the temperature sensor
detects overly hot air entering the drum's chamber, the heating
assembly can be deactivated or cycled.
[0004] To further assist with regulating operation of the heating
assembly, certain dryer appliances include a thermostat mounted to
the heating assembly. The thermostat is configured for cycling at a
threshold temperature. When the thermostat cycles, the heating
assembly can be deactivated. Thermostats generally have an expected
lifetime defined by a number of cycles the thermostats can be
expected to perform. Thus, cycling of the thermostat is preferably
limited to avoid approaching the expected lifetime of the
thermostat. However, certain dryer conditions can cause the
thermostat to trip frequently, such as when dryer appliances are
operating in a restricted condition.
[0005] Accordingly, a dryer appliance with features for limiting
cycling of a thermostat of the dryer appliance would be useful. In
particular, a dryer appliance with features for limiting cycling of
a thermostat of the dryer appliance when the dryer appliance is
operating in a restricted condition would be useful.
BRIEF DESCRIPTION OF THE INVENTION
[0006] The present subject matter provides a dryer appliance and a
method for operating a dryer appliance. The method includes
monitoring a first temperature sensor of the dryer appliance in
order to determine a number of cycles of the first temperature
sensor. If the number of cycles of the heating element exceeds a
threshold number, a temperature set point of a second temperature
sensor of the dryer appliance is reduced. The method can assist
with reducing or avoiding excessive cycling of the first
temperature sensor. 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.
[0007] In a first exemplary embodiment, a method for operating a
dryer appliance is provided. The method includes operating the
dryer appliance in order to dry articles within a drum of the dryer
appliance, monitoring a first temperature sensor of the dryer
appliance in order to determine a number of cycles of the first
temperature sensor during the step of operating, reducing a
temperature set point of a second temperature sensor of the dryer
appliance if the number of cycles of the first temperature sensor
exceeds a threshold number during the step of monitoring.
[0008] In a second exemplary embodiment, a dryer appliance is
provided. The dryer appliance includes a cabinet and a drum
rotatably mounted within the cabinet. The drum defines a chamber
for receipt of articles for drying. A motor is configured for
selectively rotating the drum within the cabinet. A heating
assembly is configured for directing a flow of heated fluid into
the chamber of the drum. The heating assembly includes a housing, a
heating element disposed within the housing, and a duct extending
between the housing and the drum. The duct has an outlet positioned
at the chamber of the drum. A first temperature sensor is
positioned at the housing. A second temperature sensor is
positioned at the outlet of the duct. A controller is in
communication with the motor, the heating element and the first and
second temperature sensors. The controller is configured for
setting a temperature set point of the second temperature sensor to
a first temperature set point, determining if an operating
condition of the dryer appliance is a restricted condition,
adjusting the temperature set point of the second temperature
sensor to a second temperature set point if the operating condition
is the restricted condition at the step of determining, monitoring
the first temperature sensor in order to determine a number of
cycles of the first temperature sensor, and changing the
temperature set point of the second temperature sensor to a third
temperature set point if the number of cycles of the first
temperature sensor exceeds a threshold number during the step of
monitoring.
[0009] In a third exemplary embodiment, a method for operating a
dryer appliance is provided. The method includes setting a
temperature set point of a thermistor of the dryer appliance to a
first temperature set point, determining if an operating condition
of the dryer appliance is a restricted condition, adjusting the
temperature set point of the thermistor to a second temperature set
point if the operating condition is the restricted condition at the
step of determining, monitoring a thermostat of the dryer appliance
in order to determine a number of cycles of the thermostat, and
changing the temperature set point of the thermistor to a third
temperature set point if the number of cycles of the thermostat
exceeds a threshold number during the step of monitoring.
[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.
[0012] FIG. 1 provides a perspective view of a dryer appliance
according to an exemplary embodiment of the present subject
matter.
[0013] FIG. 2 provides a perspective view of the exemplary dryer
appliance of FIG. 1 with portions of a cabinet of the exemplary
dryer appliance removed to reveal certain components of the
exemplary dryer appliance.
[0014] FIG. 3 provides a schematic view of certain components of
the exemplary dryer appliance of FIG. 1.
[0015] FIG. 4 illustrates a method for operating a dryer appliance
according to an exemplary embodiment of the present subject
matter.
[0016] FIG. 5 illustrates a method for operating a dryer appliance
according to an additional exemplary embodiment of the present
subject matter.
[0017] FIGS. 6 and 7 illustrate plots of time versus exemplary
temperature measurements of a temperature sensor.
DETAILED DESCRIPTION
[0018] 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.
[0019] FIG. 1 illustrates a dryer appliance 10 according to an
exemplary embodiment of the present subject matter. FIG. 2 provides
another perspective view of dryer appliance 10 with a portion of a
cabinet or housing 12 of dryer appliance 10 removed in order to
show certain components of dryer appliance 10. While described in
the context of a specific embodiment of dryer appliance 10, using
the teachings disclosed herein it will be understood that dryer
appliance 10 is provided by way of example only. Other dryer
appliances having different appearances and different features may
also be utilized with the present subject matter as well. Dryer
appliance 10 defines a vertical direction V, a lateral direction L,
and a transverse direction T. The vertical direction V, lateral
direction L, and transverse direction T are mutually perpendicular
and form and orthogonal direction system.
[0020] Cabinet 12 includes a front panel 14, a rear panel 16, a
pair of side panels 18 and 20 spaced apart from each other by front
and rear panels 14 and 16, a bottom panel 22, and a top cover 24.
Within cabinet 12 is a drum or container 26 mounted for rotation
about a substantially horizontal axis, e.g., that is parallel or
substantially parallel to the lateral direction L. Drum 26 defines
a chamber 25 for receipt of articles, e.g., clothing, linen, etc.,
for drying. Drum 26 extends between a front portion 37 and a back
portion 38, e.g., along the lateral direction L.
[0021] A motor 31 is configured for rotating drum 26 about the
horizontal axis, e.g., via a pulley and a belt (not shown). Drum 26
is generally cylindrical in shape, having an outer cylindrical wall
or cylinder 28 and a front flange or wall 30 that defines an entry
32 of drum 26, e.g., at front portion 37 of drum 26, for loading
and unloading of articles into and out of chamber 25 of drum 26. A
plurality of tumbling ribs 27 are provided within chamber 25 of
drum 26 to lift articles therein and then allow such articles to
tumble back to a bottom of drum 26 as drum 26 rotates. Drum 26 also
includes a back or rear wall 34, e.g., at back portion 38 of drum
26. Cylinder 28 is rotatable on rear wall 34 as will be understood
by those skilled in the art.
[0022] A duct 41 is mounted to rear wall 34 and receives heated air
that has been heated by a heating assembly or system 40. Duct 41
extends between heating assembly 40 and drum 26. Duct 41 is
configured for directing a flow of heated from heating assembly 40
into chamber 25 of drum 26 and has an outlet 82 positioned at
chamber 25 of drum 26. Heated air flows out of duct 41 into chamber
25 of drum 25 at outlet 82.
[0023] Motor 31 is also in mechanical communication with an air
handler 48 such that motor 31 rotates a fan 49, e.g., a centrifugal
fan, of air handler 48. Air handler 48 is configured for drawing
air through chamber 25 of drum 26, e.g., in order to dry articles
located therein as discussed in greater detail below. In
alternative exemplary embodiments, dryer appliance 10 may include
an additional motor (not shown) for rotating fan 49 of air handler
48 independently of drum 26.
[0024] Drum 26 is configured to receive heated air that has been
heated by a heating assembly 40, e.g., in order to dry damp
articles disposed within chamber 25 of drum 26. Heating assembly 40
includes a heating element 42 (FIG. 3), such as a gas burner or an
electrical resistance heating element, for heating air. Heating
element 42 is positioned within a housing 44 of heating assembly 40
in cabinet 12. As discussed above, during operation of dryer
appliance 10, motor 31 rotates drum 26 and fan 49 of air handler 48
such that air handler 48 draws air through chamber 25 of drum 26
when motor 31 rotates fan 49. In particular, ambient air enters
heating assembly 40 via an entrance 51 due to air handler 48 urging
such ambient air into entrance 51. Such ambient air is heated
within heating assembly 40 by heating element 42 and exits heating
assembly 40 as heated air. Air handler 48 draws such heated air
through duct 41 to drum 26. The heated air enters drum 26 at outlet
82 of duct 41 positioned at rear wall 34 of drum 26.
[0025] Within chamber 25, the heated air can accumulate moisture,
e.g., from damp articles disposed within chamber 25. In turn, air
handler 48 draws moisture statured air through a screen filter (not
shown) which traps lint particles. Such moisture statured air then
enters an exit conduit 46 and is passed through air handler 48 to
an exhaust conduit 52. From exhaust conduit 52, such moisture
statured air passes out of dryer appliance 10 through a vent 53
defined by cabinet 12. After the clothing articles have been dried,
they are removed from the drum 26 via entry 32. A door 33 provides
for closing or accessing drum 26 through entry 32.
[0026] A cycle selector knob 70 is mounted on a cabinet backsplash
71 and is in communication with a processing device or controller
56. Signals generated in controller 56 operate motor 31 and heating
assembly 40 in response to the position of selector knobs 70.
Alternatively, a touch screen type interface, knobs, sliders,
buttons, speech recognition, etc., mounted to cabinet backsplash 71
can permit a user to input control commands for dryer appliance 10
and/or controller 56.
[0027] Controller 56 may include memory and one or more processing
devices such as microprocessors, CPUs or the like, such as general
or special purpose microprocessors operable to execute programming
instructions or micro-control code associated with operation of
dryer appliance 10. The memory can represent random access memory
such as DRAM, or read only memory such as ROM or FLASH. The
processor executes programming instructions stored in the memory.
The memory may be a separate component from the processor or may be
included onboard within the processor. Alternatively, controller 56
may be constructed without using a microprocessor, e.g., using a
combination of discrete analog and/or digital logic circuitry (such
as switches, amplifiers, integrators, comparators, flip-flops, AND
gates, and the like) to perform control functionality instead of
relying upon software.
[0028] FIG. 3 provides a schematic view of certain components of
dryer appliance 10. As may be seen in FIG. 3, controller 56 is in
operative communication with various components of dryer appliance
10. In particular, controller 56 is in operative communication with
motor 31 and heating assembly 40. Thus, upon receiving an
activation signal from cycle selector knob 70, controller 56 can
activate motor 31 to rotate drum 26 and fan 49 of air handler 48.
Controller 56 can also activate heating assembly 40 in order to
generate heated air for drum 26, e.g., in the manner described
above.
[0029] Controller 56 is also in communication with a first
temperature sensor 90 and a second temperature sensor 92. First
temperature sensor 90 is positioned at or adjacent heating assembly
40, e.g., on housing 44 of heating assembly 40. Thus, first
temperature sensor 90 may be configured for measuring or detecting
a temperature of housing 44 of heating assembly 40 or heated air
within housing 44 of heating assembly 40. In response to the
temperature of housing 44 measured by first temperature sensor 90
exceeding a maximum permitted temperature, heating assembly 40 or
any other component of dryer appliance 10 can be deactivated in
order to reduce the temperature of heated air within heating
assembly 40 and duct 41. First temperature sensor 90 can be any
suitable sensor. For example, first temperature sensor 90 may be a
thermostat, such as a bimetallic switch.
[0030] Second temperature sensor 92 is configured for measuring a
temperature of heated air within duct 41. Second temperature sensor
92 can be positioned at any suitable location within dryer
appliance 10. For example, second temperature sensor 92 may be
positioned within or on duct 41, such as at outlet 82 of duct 41.
Controller 56 can receive a signal from second temperature sensor
92 that corresponds to a temperature measurement of heated air
within duct 41, e.g., a temperature measurement of heated air
exiting duct 41 at outlet 82. Second temperature sensor 92 can be
any suitable sensor. For example, second temperature sensor 92 may
be a thermistor or a thermocouple.
[0031] Dryer appliance 10 also includes features for improving
performance of dryer appliance 10. In particular, dryer appliance
10 includes features for limiting cycling of first temperature
sensor 90 of dryer appliance 10. Such features are discussed in
greater detail below.
[0032] As will be understood by those skilled in the art, dryer
appliance 10 can be installed at various locations. The particular
arrangement and setup of dryer appliance 10 at such locations can
affect performance of dryer appliance 10. For example, a conduit
(not shown) can be attached to vent 53 (FIG. 2) of dryer appliance
10 and receive moisture saturated air therefrom. The conduit can
direct such moisture statured air out of a building housing dryer
appliance 10. Thus, the conduit assists dryer appliance 10 with
drying articles. However, the length of conduit can affect
performance of dryer appliance 10. For example, if the conduit is
relatively long, it can be more difficult for air handler 48 to
urge air out of vent 53 and through the conduit. Conversely, it can
be relatively easier for air handler 48 to urge air out of vent 53
and through the conduit if the conduit is relatively short. The
length of the conduit can vary depending upon the location of dryer
appliance 10 within building. Thus, if dryer appliance 10 is
located near an exterior wall, the conduit can be relatively short.
Conversely, the conduit can be relatively long if dryer appliance
10 is distant from the exterior wall.
[0033] In a similar manner, lint and other debris within the
conduit can also affect performance of dryer appliance 10. For
example, if the conduit has a relatively large volume of debris
therein, it can be more difficult for air handler 48 to urge air
out of vent 53 and through the conduit. Conversely, it can be
relatively easier for air handler 48 to urge air out of vent 53 and
through the conduit if the conduit has a relatively small volume of
debris therein.
[0034] Accordingly, the length of the conduit, the volume of debris
within the conduit, and other factors can affect performance of
dryer appliance 10. When such factors negatively affect performance
of dryer appliance 10 to a significant degree, dryer appliance 10
is operating in a restricted condition. Conversely, dryer appliance
10 is operating in an unrestricted condition when such factors do
not affect performance of dryer appliance 10 to a significant
degree. As an example, when the conduit is relatively long and/or
the conduit contains a relatively large volume of debris, dryer
appliance 10 is operating in the restricted condition. Conversely,
dryer appliance 10 is operating in the unrestricted condition when
the conduit is relatively short and/or the conduit contains a
relatively small volume of debris.
[0035] In the unrestricted condition, a volume of heated air
flowing out of duct 41 can be relatively high, and a temperature of
the heated air can be relatively low. Conversely, in the restricted
condition, the volume of heated air flowing out of duct 41 can be
relatively low, and the temperature of the heated air flowing out
of duct 41 can be relatively high. Due to the increased temperature
of heated air in duct 41 and housing 44 of heating assembly in the
restricted condition, first temperature sensor 90 can trip or cycle
and deactivate heating assembly 40. First temperature sensor 90 has
an expected life time defined by a number of trips or cycles
performed by first temperature sensor 90. Dryer appliance 10
includes features for limiting or reducing cycling of first
temperature sensor 90 in order to preserve first temperature sensor
90. In particular, dryer appliance 10 includes features for
avoiding unnecessary or excessive cycling of first temperature
sensor 90 when dryer appliance 10 is operating in the restricted
condition.
[0036] FIG. 4 illustrates a method 400 for operating a dryer
appliance according to an exemplary embodiment of the present
subject matter. Method 400 can be used to operate any suitable
dryer appliance. For example, method 400 may be used to operate
dryer appliance 10 (FIG. 1). In particular, controller 56 (FIG. 3)
may be programmed to implement method 400.
[0037] At step 410, dryer appliance 10 is operated in order to dry
articles within drum 26. As an example, a user can utilize knobs 70
to activate dryer appliance 10. In response to the user actuating
knobs 70, controller 56 can operate motor 31 to spin drum 26 and
fan 49 of air handler 48 at step 410. Controller 56 can also
activate heating element 42 of heating assembly 40 to supply heated
air to chamber 25 of drum 26 at step 410.
[0038] At step 420, first temperature sensor 90 is monitored in
order to determine a number of cycles of first temperature sensor
90 during step 410. As an example, controller 56 can receive a
signal from first temperature sensor 90 each time first temperature
sensor 90 cycles, and controller 56 can tally or sum the number of
cycles of first temperature sensor 90 during step 410 in order to
determine the number of cycles of first temperature sensor 90 at
step 420. As another example, controller 56 can detect heating
element 42 of heating assembly 40 deactivating during step 410. It
can be inferred that first temperature sensor 90 has cycled when
heating element 42 of heating assembly 40 deactivates during step
410 if controller 56 has not expressly deactivated heating assembly
40. Thus, each time heating element 42 of heating assembly 40
deactivates during step 410, controller 56 can infer that first
temperature sensor 90 has cycled, and controller 56 can tally or
sum the number of times heating element 42 of heating assembly 40
deactivates during step 410 in order to determine the number of
cycles of first temperature sensor 90 at step 420.
[0039] At step 430, controller 56 determines if the number of
cycles of first temperature sensor 90 from step 420 exceeds a
threshold number. As an example, at step 420, controller 56 can
compare the number of cycles of first temperature sensor 90 from
step 420 to the threshold number. If the number of cycles of first
temperature sensor 90 does not exceed the threshold number at step
430, controller 56 can continue to monitor first temperature sensor
90 at step 420. Conversely, controller 56 reduces a temperature set
point of second temperature sensor 92 at step 440 if the number of
cycles of the first temperature sensor 90 exceeds the threshold
number at step 430.
[0040] The threshold number can be any suitable number. For
example, the threshold number may be greater than fifteen. As
another example, the threshold number may be about twenty. The
threshold number may be selected in order to avoid excessive
cycling of first temperature sensor 90 and premature failure of
first temperature sensor 90. In particular, by monitoring the
number of cycles of first temperature sensor 90 and reducing the
temperature set point of second temperature sensor 92 at step 440
if the number of cycles of first temperature sensor 90 exceeds the
threshold number, method 400 can assist with limiting or preventing
cycling of first temperature sensor 90 after step 440 and prevent
overcycling of first temperature sensor 90 during step 410.
[0041] For example, after reducing or adjusting the temperature set
point of second temperature sensor 92 at step 440, controller 56
can regulate the temperature of heated air flowing through duct 41
with second temperature sensor 92 rather than first temperature
sensor 90. Thus, the temperature set point of second temperature
sensor 92 at step 440 can be selected such that cycling of first
temperature sensor 90 is limited or prevented. For example, the
temperature set point of second temperature sensor 92 at step 440
can be less than a tripping or cycling temperature of first
temperature sensor 90. In such a manner, method 400 limits usage of
first temperature sensor 90 during step 410 and can prevent first
temperature sensor 90 from approaching its estimated life time
earlier than expected. Method 400 can particularly assist with
hindering overuse or overcycling of first temperature sensor 90
when dryer appliance 10 is operating in the restricted
condition.
[0042] In method 400, controller 56 can also select an operating
temperature of dryer appliance 10 based at least in part on the
operating condition of dryer appliance 10. For example, controller
56 can select the operating temperature of dryer appliance 10 from
a first temperature set point and a second temperature set point.
The first and second temperature set points are different than each
other. The first temperature set point can correspond to the
maximum operating temperature of dryer appliance 10 in the
unrestricted condition. Conversely, the second temperature set
point can correspond to a maximum operating temperature of dryer
appliance 10 in the restricted condition. Thus, controller 56
selects the second temperature set point if the operating condition
of dryer appliance 10 is the restricted condition, and controller
56 selects the first temperature set point if the operating
condition of dryer appliance 10 is the unrestricted condition. By
selecting the maximum operating temperature of dryer appliance 10
based upon the operating condition of dryer appliance 10,
performance of dryer appliance 10 can be improved.
[0043] The first and second temperature set points can be
established in any suitable manner at step 410. For example, the
first and second temperature set points may be selected by a user
of dryer appliance 10. As another example, the first and second
temperature set points may be selected by a manufacturer of dryer
appliance 10, e.g., during assembly or manufacture of dryer
appliance 10.
[0044] FIG. 5 illustrates a method 500 for operating a dryer
appliance according to another exemplary embodiment of the present
subject matter. Method 500 can be used to operate any suitable
dryer appliance. For example, method 500 may be used to operate
dryer appliance 10 (FIG. 1). In particular, controller 56 (FIG. 3)
may be programmed to implement method 500.
[0045] At step 510, dryer appliance 10 is operated in order to dry
articles within drum 26. As an example, a user can utilize knobs 70
to activate dryer appliance 10. In response to the user actuating
knobs 70, controller 56 can operate motor 31 to spin drum 26 and
fan 49 of air handler 48 at step 510. Controller 56 can also
activate heating element 42 of heating assembly 40 to supply heated
air to chamber 25 of drum 26 at step 510.
[0046] At step 520, a temperature set point of second temperature
sensor 92 is set to a first temperature set point. As an example,
controller 56 can set the temperature set point of second
temperature sensor 92 to the first temperature set point at step
510. With the temperature set point of second temperature sensor 92
set to the first temperature set point, controller 56 can
deactivate or cycle heating assembly 40 when a temperature
measurement of second temperature sensor 92 exceeds the first
temperature set point during step 510.
[0047] At step 530, controller 56 determines if an operating
condition of dryer appliance 10 is a restricted condition. If the
operating condition of dryer appliance 10 is not the restricted
condition at step 530, controller 56 can continue to monitor
temperature measurements of second temperature sensor 92 with
second temperature sensor 92 set to the first temperature set point
during step 510. Conversely, controller 56 adjusts or reduces the
temperature set point of second temperature sensor 92 to a second
temperature set point at step 540 if the operating condition of
dryer appliance 10 is the restricted condition at step 530.
[0048] With the temperature set point of second temperature sensor
92 set to the second temperature set point, controller 56 can
deactivate or cycle heating assembly 40 when the temperature
measurement of second temperature sensor 92 exceeds the second
temperature set point during step 510. The first and second
temperature set points can be any suitable temperatures. For
example, the first temperature set point may be greater than the
second temperature set point. Thus, in the unrestricted condition,
controller 56 can operate dryer appliance 10 such that the
temperature set point of second temperature sensor 92 is the first
temperature set point, and controller 56 can operate dryer
appliance 10 such that the temperature set point of second
temperature sensor 92 is the second temperature set point in the
restricted condition. When the first temperature set point is
greater than the second temperature set point, articles within drum
26 can dry more quickly if controller 56 operates dryer appliance
10 such that the temperature set point of second temperature sensor
92 is the first temperature set point, e.g., due to controller 56
permitting heated air exiting outlet 82 to have a higher
temperature relative to the second temperature set point.
[0049] It is to be appreciated that one ordinarily skilled in the
art will realize that well-known methods may be applied or
mechanisms used to determine or establish the operating condition
of dryer appliance 10 at step 530. As an example, a user can
utilize knobs 70 to indicate the operating condition of dryer
appliance 10. As another example, the operating condition of dryer
appliance 10 may be established in accordance with methods
described in U.S. patent application Ser. No. 13/787,183 to Ionelia
Silvia Prajescu et al. filed on Mar. 6, 2013, the disclosure of
which is incorporated by reference herein. Such methods are
discussed in greater detail below.
[0050] To assist with improving performance of dryer appliance 10,
controller 56 can determine an operating condition of dryer
appliance 10 at step 530. In particular, controller 56 can
determine if the operating condition of dryer appliance 10 is the
restricted condition or the unrestricted condition. For example,
controller 56 can calculate a temperature change for heated air
within duct 41 between a first time and a second, e.g., later,
time. Controller 56 can determine that dryer appliance 10 is
operating in the restricted condition or the unrestricted condition
based at least in part on the temperature change for the heated air
between the first and second times. In particular, controller 56
can determine that dryer appliance 10 is operating in the
restricted condition if the temperature change for the heated air
is greater than a threshold value between the first and second
times. Conversely, controller 56 can determine that dryer appliance
10 is operating in the unrestricted condition if the temperature
change for the heated air is less than the threshold value between
the first and second times.
[0051] At step 550, first temperature sensor 90 is monitored in
order to determine a number of cycles of first temperature sensor
90, e.g., during step 510. As an example, controller 56 can receive
a signal from first temperature sensor 90 each time first
temperature sensor 90 cycles during step 510, and controller 56 can
tally or sum the number of cycles of first temperature sensor 90
during step 510 in order to determine the number of cycles of first
temperature sensor 90 at step 550. As another example, controller
56 can detect heating element 42 of heating assembly 40
deactivating during step 550. It can be inferred that first
temperature sensor 90 has cycled when heating element 42 of heating
assembly 40 deactivates during step 510 if controller 56 has not
expressly deactivated heating assembly 40. Thus, each time heating
element 42 of heating assembly 40 deactivates during step 510,
controller 56 can infer that first temperature sensor 90 has
cycled, and controller 56 can tally or sum the number of times
heating element 42 of heating assembly 40 deactivates during step
510 in order to determine the number of cycles of first temperature
sensor 90 at step 550.
[0052] At 560, controller 56 determines if the number of cycles of
first temperature sensor 90 from step 550 exceeds a threshold
number. As an example, at step 560, controller 56 can compare the
number of cycles of first temperature sensor 90 from step 550 to
the threshold number. If the number of cycles of first temperature
sensor 90 does not exceed the threshold number at step 560,
controller 56 can continue to monitor first temperature sensor 90
at step 550. Conversely, controller 56 changes or reduces the
temperature set point of second temperature sensor 92 to a third
temperature set point at step 570 if the number of cycles of the
first temperature sensor 90 exceeds the threshold number at step
560.
[0053] The threshold number can be any suitable number. For
example, the threshold number may be greater than fifteen. As
another example, the threshold number may be about twenty. The
threshold number may be selected in order to avoid excessive
cycling of first temperature sensor 90. In particular, by
monitoring the number of cycles of first temperature sensor 90 and
changing the temperature set point of second temperature sensor 92
to the third temperature set point at step 570 if the number of
cycles of first temperature sensor 90 exceeds the threshold number,
method 500 can assist with limiting or preventing cycling of first
temperature sensor 90 after step 570.
[0054] For example, after changing or reducing the temperature set
point of second temperature sensor 92 to the third temperature set
point at step 570, controller 56 can regulate the temperature of
heated air flowing through duct 41 with second temperature sensor
92 rather than first temperature sensor 90. Thus, the third
temperature set point of second temperature sensor 92 can be
selected such that cycling of first temperature sensor 90 is
limited or prevented. For example, the third temperature set point
of second temperature sensor 92 at step 570 can be less than a
tripping or cycling temperature of first temperature sensor 90. In
such a manner, method 500 limits usage of first temperature sensor
90 during step 510 and can prevent first temperature sensor 90 from
approaching its estimated life time earlier than expected. Method
500 can particularly assist with hindering overuse or overcycling
of first temperature sensor 90 when dryer appliance 10 is operating
in the restricted condition.
[0055] FIGS. 6 and 7 illustrate plots of time versus exemplary
temperature measurements of second temperature sensor 92. In FIG.
6, the operating condition of dryer appliance 10 is determined to
be the unrestricted condition at step 530. Thus, controller 56
monitors temperature measurements of second temperature sensor 92
with second temperature sensor 92 set to the first temperature set
point after detecting the unrestricted condition in FIG. 6.
Conversely, the operating condition of dryer appliance 10 is
determined to be the restricted condition at step 530 in FIG. 7.
Thus, in FIG. 7, controller 56 monitors temperature measurements of
second temperature sensor 92 with second temperature sensor 92 set
to the second temperature set point after detecting the restricted
condition.
[0056] As may be seen in FIG. 7, during an initial portion
(indicated with bracket I) of a time interval of the drying
operation, a slope or first derivative of temperature measurements
from second temperature sensor 92 with respect to time increases
rapidly when heating assembly 40 is activated. The restricted
condition may correspond to the condition of dryer appliance 10
when the slope or first derivative of temperature measurements from
second temperature sensor 92 with respect to time exceeds a
threshold value. Thus, the restricted condition can be detected at
step 530 due to a magnitude of the slope or first derivative of
temperature measurements from second temperature sensor 92 during
the initial portion I of the time interval.
[0057] In FIGS. 6 and 7, first temperature sensor 90 cycles twenty
times during operation of the dryer appliance 10 (indicated with
bracket N). After first temperature sensor 90 has cycled twenty
times, controller 56 changes or reduces the temperature set point
of second temperature sensor 92 to the third temperature set point
at step 570, e.g., such that first temperature sensor 90 does not
cycle for a remainder of the drying operation. Thus, in FIGS. 6 and
7, controller 56 utilizes second temperature sensor 92 to regulate
the temperature of heated air exiting duct 41 after first
temperature sensor 90 has cycled twenty times because the
temperature set point of second temperature sensor 92 has been
reduced to the third temperature set point.
[0058] The first, second and third temperature set points of second
temperature sensor 92 can be established in any suitable manner.
For example, the first, second and third temperature set points of
second temperature sensor 92 may be selected by a user of dryer
appliance 10. As another example, first, second and third
temperature set points of second temperature sensor 92 may be
selected by a manufacturer of dryer appliance 10, e.g., during
assembly or manufacture of dryer appliance 10.
[0059] The first, second and third temperature set points of second
temperature sensor 92 can be any suitable temperatures. In certain
exemplary embodiments, the first temperature set point of second
temperature sensor 92 may be greater than the second temperature
set point of second temperature sensor 92. Similarly, the second
temperature set point of second temperature sensor 92 may be
greater than the third temperature set point of second temperature
sensor 92. As an example, the third temperature set point of second
temperature sensor 92 may be less than about three hundred degrees
Fahrenheit, such as about two hundred and forty degrees
Fahrenheit.
[0060] 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.
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