Patent Grant
10669667
The present subject matter relates generally to dryer appliances, and more particularly to systems and methods for detecting the moisture content of clothes within dryer appliances.
Dryer appliances generally include a cabinet with a drum rotatably mounted therein. During operation, a motor rotates the drum, e.g., to tumble articles located within a chamber defined by the drum. Dryer appliances also generally include a heater assembly that passes heated air through the chamber in order to dry moisture-laden articles positioned therein. Typically, an air handler or blower is used to urge the flow of heated air from chamber, through a trap duct, and to the exhaust duct where it is exhausted from the dryer appliance.
Conventional dryer appliances use two stainless steel sensor rods positioned within the chamber to detect the moisture content of a laundry load. More specifically, the two sensor rods are spaced apart and positioned such that the rotation of the drum causes clothes to contact both rods. The dryer appliance measures the resistance between the sensor rods or the conduction of electric current through the clothes contacting the rods to determine their moisture content.
However, current sensor rod systems do not provide precise moisture content detection, particularly at low moisture content levels. Typically, this inaccuracy is compensated for by increasing cycle time to achieve the desired final moisture content of the clothes. In addition, the signals generated by current sensor rod systems are very dependent of the type of load being dried, e.g., with delicate loads generating noisy signals and cotton loads generating smoother signals. As a result, heavy filtering processes are required, making the signal less reliable. The size of the load being dried also affects the output of current sensor rod systems.
Accordingly, an improved system and method for detecting the moisture content of a load of clothes is desirable. More specifically, a dryer appliance having more improved and reliable means for detecting the moisture content of clothes and adjusting the dryer appliance accordingly would be particularly beneficial.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In one aspect of the present disclosure, a method of detecting a moisture content of clothes in a dryer appliance is provided. The dryer appliance includes a drum defining a chamber, a chamber temperature sensor being positioned proximate a top of the drum, an exhaust temperature sensor, and a humidity sensor being positioned proximate a top of the drum. The method includes measuring a chamber temperature using the chamber temperature sensor and an exhaust temperature using the exhaust temperature sensor. The method further includes measuring a chamber humidity using the humidity sensor and estimating the moisture content of the clothes in the dryer appliance using the chamber temperature, the exhaust temperature sensor, and the chamber humidity. The method includes adjusting at least one operating parameter of the dryer appliance in response to the estimated moisture content of the clothes.
In another aspect of the present disclosure, a dryer appliance is provided including a cabinet, a drum rotatably mounted within the cabinet, the drum defining a chamber for receipt of clothes for drying, and a top bearing positioned proximate a front of the drum. A chamber temperature sensor is positioned within the top bearing for measuring a chamber temperature, an exhaust temperature sensor is positioned within a trap duct for measuring an exhaust temperature, and a humidity sensor is positioned within the top bearing for measuring a chamber humidity. A controller is operably coupled to the temperature sensor and the humidity sensor. The controller is configured for obtaining the chamber temperature using the chamber temperature sensor, obtaining the exhaust temperature using the exhaust temperature sensor and obtaining the chamber humidity using the humidity sensor. The controller is further configured for estimating a moisture content of the clothes in the dryer appliance using the chamber temperature, the exhaust temperature, and the chamber humidity, adjusting at least one operating parameter of the dryer appliance in response to the estimated moisture content of the clothes.
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.
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.
Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.
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.
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 an orthogonal direction system. 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 container or drum 26 which defines a chamber 28 for receipt of articles, e.g., clothing, linen, etc., for drying. Drum 26 extends between a front portion and a back portion, e.g., along the transverse direction T. In example embodiments, drum 26 is rotatable, e.g., about an axis that is parallel to the transverse direction T, within cabinet 12. A door 30 is rotatably mounted to cabinet 12 for providing selective access to drum 26.
An air handler 32, such as a blower or fan, may be provided to motivate an airflow (not shown) through an entrance air passage 34 and an air exhaust passage 36. Specifically, air handler 32 may include a motor 38 which may be in mechanical communication with a blower fan 40, such that motor 38 rotates blower fan 40. Air handler 32 is configured for drawing air through chamber 28 of drum 26, e.g., in order to dry articles located therein, as discussed in greater detail below. In alternative example embodiments, dryer appliance 10 may include an additional motor (not shown) for rotating fan 40 of air handler 32 independently of drum 26.
Drum 26 may be configured to receive heated air that has been heated by a heating assembly 50, e.g., in order to dry damp articles disposed within chamber 28 of drum 26. Heating assembly 50 includes a heater 52 that is in thermal communication with chamber 28. For instance, heater 52 may include one or more electrical resistance heating elements or gas burners, for heating air being flowed to chamber 28. As discussed above, during operation of dryer appliance 10, motor 38 rotates fan 40 of air handler 32 such that air handler 32 draws air through chamber 28 of drum 26. In particular, ambient air enters an air entrance passage defined by heating assembly 50 via an entrance 54 due to air handler 32 urging such ambient air into entrance 54. Such ambient air is heated within heating assembly 50 and exits heating assembly 50 as heated air. Air handler 32 draws such heated air through an air entrance passage 34, including inlet duct 56, to drum 26. The heated air enters drum 26 through an outlet 58 of duct 56 positioned at a rear wall of drum 26.
Within chamber 28, the heated air can remove moisture, e.g., from damp articles disposed within chamber 28. This internal air flows in turn from chamber 28 through an outlet assembly positioned within cabinet 12. The outlet assembly generally defines an air exhaust passage 36 and includes a trap duct 60, air handler 32, and an exhaust conduit 62. Exhaust conduit 62 is in fluid communication with trap duct 60 via air handler 32. More specifically, exhaust conduit 62 extends between an exhaust inlet 64 and an exhaust outlet 66. According to the illustrated embodiment, exhaust inlet 64 is positioned downstream of and fluidly coupled to air handler 32, and exhaust outlet 66 is defined in rear panel 16 of cabinet 12. During a dry cycle, internal air flows from chamber 28 through trap duct 60 to air handler 32, e.g., as an outlet flow portion of airflow. As shown, air further flows through air handler 32 and to exhaust conduit 62.
The internal air is exhausted from dryer appliance 10 via exhaust conduit 62. In some embodiments, an external duct (not shown) is provided in fluid communication with exhaust conduit 62. For instance, the external duct may be attached (e.g., directly or indirectly attached) to cabinet 12 at rear panel 16. Any suitable connector (e.g., collar, clamp, etc.) may join the external duct to exhaust conduit 62. In residential environments, the external duct may be in fluid communication with an outdoor environment (e.g., outside of a home or building in which dryer appliance 10 is installed). During a dry cycle, internal air may thus flow from exhaust conduit 62 and through the external duct before being exhausted to the outdoor environment.
In exemplary embodiments, trap duct 60 may include a filter portion 68 which includes a screen filter or other suitable device for removing lint and other particulates as internal air is drawn out of chamber 28. The internal air is drawn through filter portion 68 by air handler 32 before being passed through exhaust conduit 62. After the clothing articles have been dried (or a drying cycle is otherwise completed), the clothing articles are removed from drum 26, e.g., by accessing chamber 28 by opening door 30. The filter portion 68 may further be removable such that a user may collect and dispose of collected lint between drying cycles.
One or more selector inputs 80, such as knobs, buttons, touchscreen interfaces, etc., may be provided on a cabinet backsplash 82 and may be in communication with a processing device or controller 84. Signals generated in controller 84 operate motor 38, heating assembly 50, and other system components in response to the position of selector inputs 80. Additionally, a display 86, such as an indicator light or a screen, may be provided on cabinet backsplash 82. Display 86 may be in communication with controller 84, and may display information in response to signals from controller 84.
As used herein, “processing device” or “controller” may refer to one or more microprocessors or semiconductor devices and is not restricted necessarily to a single element. The processing device can be programmed to operate dryer appliance 10. The processing device may include, or be associated with, one or more memory elements (e.g., non-transitory storage media). In some such embodiments, the memory elements include electrically erasable, programmable read only memory (EEPROM). Generally, the memory elements can store information accessible processing device, including instructions that can be executed by processing device. Optionally, the instructions can be software or any set of instructions and/or data that when executed by the processing device, cause the processing device to perform operations. For certain embodiments, the instructions include a software package configured to operate appliance 10 and execute certain cycles or operating modes.
In some embodiments, dryer appliance 10 also includes one or more sensors that may be used to facilitate improved operation of dryer appliance, such as described below. For example, dryer appliance 10 may include one or more temperature sensors which are generally operable to measure internal temperatures in dryer appliance 10 and/or one or more airflow sensors which are generally operable to detect the velocity of air (e.g., as an air flow rate in meters per second, or as a volumetric velocity in cubic meters per second) as it flows through the appliance 10. In some embodiments, controller 84 is configured to vary operation of heating assembly 50 based on one or more temperatures detected by the temperature sensors or air flow measurements from the airflow sensors.
Referring now generally to
As used herein, “moisture content” is intended to refer to an estimated amount of water within clothes in chamber 28 of dryer appliance 10. In general, moisture content may represent the humidity within a volume of clothes, and may be referred to as the “remaining moisture content” (RMC) to refer to the amount of liquid remaining within clothes during a drying cycle. The term “final moisture content”(FMC) may be used herein to refer to a desired amount of moisture content or a moisture content threshold below which the clothes may be considered dry. For example, according to exemplary embodiments, the FMC may be less than 3% for dry clothes and less than 15% for moderately dry or slightly damp clothes.
Referring now generally to
As described herein, “temperature sensor” may refer to any suitable type of temperature sensor. For example, the temperature sensors may be thermocouples, thermistors, or resistance temperature detectors. Similarly, “humidity sensor” may refer to any suitable type of humidity sensor, such as capacitive digital sensors, resistive sensors, and thermal conductivity humidity sensors. In addition, temperature sensors 100, 104 and humidity sensor 102 may be mounted at any suitable location and in any suitable manner for obtaining a desired temperature or humidity measurement, either directly or indirectly. Although exemplary positioning of certain sensors is described below, it should be appreciated that dryer appliance 10 may include any other suitable number, type, and position of temperature and/or humidity sensors according to alternative embodiments.
According to the illustrated embodiment, temperature sensor 100 and humidity sensor 102 are positioned within a top bearing 110 of dryer appliance 10. In this regard, top bearing 110 is generally positioned at a front of drum 26 and cabinet 12. In addition, top bearing 110 and a front bulkhead 112 generally define an opening 114 through which chamber 28 may be accessed. More specifically, top bearing 110 is positioned above front bulkhead 112 and defines a surface on which drum 26 may rotate. As illustrated, top bearing 110 may define an outer surface 116 and an inner surface 118. In this regard, outer surface 116 is exposed to or faces chamber 28, while inner surface 118 is mounted on front panel 14 and defines a cavity 120 which may house electronic components outside of chamber 28.
For example, as best shown in
In addition, according to the illustrated embodiment, temperature sensor 100 and humidity sensor 102 are mounted on a single chip 126 that is operably coupled to controller 84, e.g., for performing methods described herein. In addition, in order to permit chamber air to contact temperature sensor 100 and humidity sensor 102, top bearing 110 may define a plurality of holes 130 through which the chamber air may pass into cavity 120. As shown, top bearing 110 may further define mounting features 132 for locating and mounting chip 126 onto top bearing 110. For example, as illustrated, mounting features 132 include pin locators, supports, and mounting bosses, for properly aligning, supporting, and fastening chip 126, respectively.
Notably, as illustrated, temperature sensor 100 and humidity sensor 102 are positioned proximate top cover 24 of dryer appliance 10 and at a very top of chamber 28 along the vertical direction V. In this manner, temperature and humidity measurements may be obtained at a location outside of the primary flow of air through chamber 28, and away from trap duct 60, exhaust conduit 62, etc. In this regard, the flow of heated air passing through chamber 28 generally flows from a rear of drum 26 (e.g., via outlet 58), forward along the transverse direction T, and through the trap duct 60 which is located proximate a bottom of drum 26. Therefore, by positioning temperature sensor 100 and humidity sensor 102 at the top of chamber 28, the effects of the primary flow of air may be isolated, and an ambient temperature and humidity reading may be accurately obtained. In addition, the likelihood of clothes or liquid contacting these sensors is reduced. Furthermore, temperature sensor 100 and humidity sensor 102 are positioned behind the top bearing 110 to further reduce the likelihood of erroneous measurements and to obtain true ambient temperature and humidity readings.
Now that the construction and configuration of dryer appliance 10 according to an exemplary embodiment of the present subject matter has been presented, an exemplary method 200 for detecting the moisture content of clothes in a dryer appliance according to an exemplary embodiment of the present subject matter is provided. Method 200 can be used with dryer appliance 10, or any other suitable dryer appliance. In this regard, for example, controller 84 may be configured for implementing method 200. However, it should be appreciated that the exemplary method 200 is discussed herein only to describe exemplary aspects of the present subject matter, and is not intended to be limiting.
As shown in
To facilitate discussion herein,
Referring again to
According to an exemplary embodiment, the vapor density in the drying chamber (VDC) in the dryer appliance 10 can be estimated using the following equation:
In the above equation, RHC is the measured chamber humidity (e.g., by chamber humidity sensor 102) and VDSat is a saturation vapor density. According to exemplary embodiments, the measured chamber humidity (RHC) is determined using humidity sensor 102. The saturation vapor density (VDSat) may be determined empirically, may be obtained from a lookup table, may be formulated using an equation, or may be determined in any other suitable manner. For example, according to one embodiment, estimating the moisture content (MC) may comprise determining the saturation vapor density (VDSat) using a psychometric table, which generally correlates a temperature of air to the amount of water vapor that may be contained within a given volume of that air. For example, an exemplary psychometric table to determine a saturation vapor density (VDSat) as a function of the chamber temperature (TC) in degrees Celsius is provided in Table 1 below:
Therefore, by using the measured chamber temperature (TC) determined at step 210 (e.g., as measured by chamber temperature sensor 100), a psychometric table (e.g., Table 1) may be used to determine the saturation vapor density (VDSat) within the dryer chamber. According still another embodiment, a polynomial regression equation may be used to determine the saturation vapor density (VDSat). For example, the polynomial regression equation may be determined from the data in a psychometric table, such as Table 1, resulting in equation shown below:
VDSat(TC)=−0.0003·TC3+0.0353·TC2−0.0152·TC+4.0905
Notably, using the saturation vapor density (VDSat) and the measured chamber humidity (RHC), a vapor density in the chamber (VDC) may be calculated using the equation above. Using the vapor density in the chamber (VDC) as a proxy for the vapor density at the exhaust of the chamber, an estimated relative humidity of at the exhaust (RHOUT) may by reworking the equation above as follows:
Notably, the saturation vapor density at the outlet (VDSat_OUT) may be calculated using a psychometric table (e.g., Table 1 above) or using the polynomial regression equation above as a function of the exhaust temperature (TOUT). Thus an estimate of the relative humidity at the exhaust (RHOUT) is calculated. This estimated relative humidity at the exhaust or the estimated outlet humidity (RHOUT) is illustrated in
Referring again to
According to exemplary embodiments of the present subject matter, dryer appliance 10 may be turned off or may enter a cool down cycle when the estimated moisture content drops below a predetermined level. For example, as used herein, a “cool down” cycle may be used to refer to a final stage of the total drying cycle where a heating element (such as heater 52) is shut off but an air handler (such as air handler 32) continues to circulate air through chamber 28 to cool drum 26 and articles of clothing positioned therein to a suitable temperature threshold, e.g., such that it is safe for a user to remove the clothes without being burned.
According still another embodiment, the at least one operating parameter is adjusted when the measured exhaust temperature 150 exceeds a temperature threshold 160 and when the estimated moisture content or outlet humidity 154 drops below a humidity threshold 162. This condition is illustrated for example in
For certain load types or sizes, it may be desirable to initiate a timed dry segment after the exhaust temperature 150 has exceeded the temperature threshold 160 and the estimated outlet humidity 154 has dropped below the humidity threshold 162. Therefore, according to exemplary embodiments, the adjusting of at least one operating parameter may include initiating a timed dry segment where a heating element remains on and the air handler continues to circulate air through the chamber for a predetermined amount of time, e.g., the amount of time to make the clothes “extra dry” or below a very low moisture content. The dryer appliance may then be shut off or an additional cool down cycle may be initiated.
Notably, the parameters measured and calculated herein may be used to improve the performance of dryer appliance 10 in other manners as well. For example, the chamber temperature, the chamber humidity, and/or the estimated moisture content may be used to detect operating issues with dryer appliance 10 or to otherwise identify ways to improve dryer performance. For example, according to an exemplary embodiment, an operating issue may be detected based on the measured chamber humidity. In this regard, for example, if the measured chamber humidity remains substantially constant for a predetermined amount of time, this may indicate the presence of a clogged filter, an empty drum, a flow restriction to the humidity sensor 102 (e.g., such as clogged holes 130), or an improper load size. It should be appreciated that as used herein, terms of approximation, such as “approximately,” “substantially,” or “about,” refer to being within a ten percent margin of error. Thus, if the measured chamber humidity vacillates about a specific humidity even though the measured chamber temperature increases, this may indicate a faulty sensor reading or other issue. In such a situation, the user may be provided with an indication to take corrective action or the appliance may automatically initiate such a corrective action.
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.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5347727 | Kim | Sep 1994 | A |
| 6122840 | Chbat et al. | Sep 2000 | A |
| 8701309 | Park et al. | Apr 2014 | B2 |
| 8974546 | Ghosh | Mar 2015 | B2 |
| 9322127 | Ashrafzadeh et al. | Apr 2016 | B2 |
| 20060130817 | Gonze | Jun 2006 | A1 |
| 20070163056 | Lee | Jul 2007 | A1 |
| 20070186438 | Woerdehoff | Aug 2007 | A1 |
| 20090313848 | Moschutz et al. | Dec 2009 | A1 |
| 20100305859 | Fogarty | Dec 2010 | A1 |
| 20120124859 | May | May 2012 | A1 |
| 20120160011 | Whittaker | Jun 2012 | A1 |
| 20150168064 | Ingrosso | Jun 2015 | A1 |
| 20160076193 | Santillan Galvan | Mar 2016 | A1 |
| 20190145817 | Shim | May 2019 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20190338458 A1 | Nov 2019 | US |
