Dryer Appliance and Method for Dryer Cycle Control

The present subject matter relates to dryer appliances and apparatuses for dryer cycle control for 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 system for passing dry, 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 through the chamber to dry the clothes.

Dryer appliances may include a mechanical timer and thermostat to control heater cycling and cycle termination. Such configurations may be relatively simple and low-cost, however, they may lack fine control for achieving more energy-efficient cycles. Dryer appliances may include an electronic controller having software configured to use a combination of timing, load moisture sensing, and temperature sensing to control cycle stages, heater pulsing, and cycle termination to improve energy efficiency. However, such configurations generally require development of electronic control boards, development and update of control software, and complex wiring across operational components, sensors, controllers, and other electronic components, resulting in generally more complex and expensive appliances.

A dryer appliance addressing these issues would be beneficial and advantageous.

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.

An aspect of the present disclosure is directed to a dryer appliance. The dryer appliance includes a heater assembly configured to generate heated air through a duct. The duct is in fluid communication with a chamber formed at a drum for receiving laundry articles for drying. An inlet portion of the duct extends from the heater assembly to the chamber to provide heated air to the chamber. An outlet portion of the duct extends from the chamber to receive air from the chamber. A heater control thermostat is positioned in thermal communication with air at the duct. The heater control thermostat includes a first bi-metal thermostat having a heater control set point relative to which the heater assembly operates to provide heated air to the chamber. An outlet sensor is positioned in communication with air at the outlet portion of duct. The outlet sensor includes a second bi-metal thermostat having a sensing temperature set point, or a conductivity sensor comprising a conductivity threshold. A controller includes a control circuit having a heater control circuit and a plurality of control stages in serial operational arrangement. The plurality of control stages includes a timer stage and a sensing stage. The heater control circuit operably couples the heater control thermostat to the heater assembly to selectively output heat based on the heater control set point at the heater control thermostat. The timer stage is configured to operate the heater assembly for a pre-determined heating period and based on the heater control set point at the heater control thermostat. The control circuit is configured to commence the sensing stage after the heating period. The sensing stage is configured to operate the heater assembly until the sensing temperature set point or the conductivity threshold at the outlet sensor is met by air at the duct. The control circuit is configured to disable heat generation at the heater assembly after the sensing temperature set point or conductivity threshold is met.

An aspect of the present disclosure is directed to a method for cycle control at a dryer appliance. The method includes positioning a heater control thermostat in thermal communication with air at an inlet portion of a duct in fluid communication with a chamber for receiving laundry articles for drying. The heater control thermostat includes a first bi-metal thermostat comprising a heater control set point relative to which a heater assembly operates to provide heated air to the chamber. The method includes positioning an outlet sensor in communication with air at an outlet portion of duct. The outlet sensor includes an outlet thermostat including a second bi-metal thermostat having a sensing temperature set point or a conductivity sensor having a conductivity threshold. The method includes operably coupling the heater control thermostat to the heater assembly to selectively output heat based on the heater control set point and a pre-determined heating period. The method includes operably coupling the outlet sensor to the heater assembly to operate the heater assembly until the sensing temperature set point or the conductivity threshold is met after operating the heater assembly for the heating period based on the heater control set point. The outlet sensor disables heat generation at the heater assembly after the sensing temperature set point is met.

An aspect of the present disclosure is directed to a controller for a dryer appliance. The controller includes a control circuit having a first heater control circuit and a plurality of control stages. The plurality of control stages includes a timer stage and a sensing stage. The first heater control circuit is operably coupled to a heater control thermostat configured to control heat output from a heater assembly based on a heater control set point. The timer stage is configured to operate the heater control circuit for a pre-determined heating period and based on the heater control set point. The control circuit is configured to commence the sensing stage after the heating period. The control circuit includes a second heater control circuit operably coupled to an outlet sensor having a sensing temperature set point or conductivity threshold. The sensing stage is configured to disable the second heater control circuit after the sensing temperature set point or conductivity threshold is met.

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.

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.

As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “includes” and “including” are intended to be inclusive in a manner similar to the term “comprising.” Similarly, the term “or” is generally intended to be inclusive (i.e., “A or B” is intended to mean “A or B or both”). In addition, here and throughout the specification and claims, range limitations may be combined and/or interchanged. Such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. The singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. The terms “upstream” and “downstream” refer to the relative flow direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the flow direction from which the fluid flows, and “downstream” refers to the flow direction to which the fluid flows.

Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “generally,” “about,” “approximately,” and “substantially,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value, or the precision of the methods or machines for constructing or manufacturing the components and/or systems. For example, the approximating language may refer to being within a 10 percent margin, i.e., including values within ten percent greater or less than the stated value. In this regard, for example, when used in the context of an angle or direction, such terms include within ten degrees greater or less than the stated angle or direction, e.g., “generally vertical” includes forming an angle of up to ten degrees in any direction, e.g., clockwise or counterclockwise, with the vertical direction V.

The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” In addition, references to “an embodiment” or “one embodiment” does not necessarily refer to the same embodiment, although it may. Any implementation described herein as “exemplary” or “an embodiment” is not necessarily to be construed as preferred or advantageous over other implementations. Moreover, 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 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.

Referring now to the figures, an exemplary laundry appliance that may be used to implement aspects of the present subject matter will be described. Specifically,provide perspective views of a dryer applianceaccording to exemplary embodiments of the present disclosure. Particularly,provides a perspective view of dryer appliance.provides another perspective view of dryer appliancewith a portion of a housing or cabinetof dryer applianceremoved in order to show certain components of dryer appliance.provides a schematic embodiment of a dryer appliancein accordance with aspects of the present disclosure.

As depicted in, dryer appliancedefines a vertical direction V, a lateral direction L, and a transverse direction T, each of which is mutually perpendicular such that an orthogonal coordinate system is defined. While described in the context of a specific embodiment of dryer appliance, using the teachings disclosed herein it will be understood that dryer applianceis 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. For instance, in some embodiments, dryer appliancecan be a combination washing machine/dryer appliance, a condenser dryer, or any other suitable laundry appliance.

Cabinetincludes a plurality of panels including a front panel, a rear panel, a pair of side panelsand(e.g., a first side paneland a second side panel) spaced apart from each other by front paneland rear panelalong the lateral direction L, a bottom panel, and a top cover. Cabinetdefines an interior volume. A container or drumis mounted for rotation about a substantially horizontal axis within the interior volumeof cabinet. Drumdefines a chamberfor receipt of articles for tumbling and/or drying. As used herein, the terms “clothing” or “articles” includes but need not be limited to fabrics, textiles, garments, linens, papers, or other items from which the extraction of moisture is desirable. Drumextends between a front portionand a back portion, e.g., along the transverse direction T. Drumalso includes a back or rear wall, e.g., at back portionof drum. For example, dryer appliancemay be configured as an electric dryer appliance with electrical heating elements or as a gas dryer appliance with gas heating elements (e.g., gas burners) for heating air.

In some embodiments, a motoris provided to rotate drumabout the horizontal axis, e.g., via a pulley and a belt (not pictured). Drumis generally cylindrical in shape. Drumhas an outer cylindrical walland a front flange or wallthat defines an openingof drum, e.g., at front portionof drum, for loading and unloading of articles into and out of chamberof drum. Drumincludes a plurality of lifters or bafflesthat extend into chamberto lift articles therein and then allow such articles to tumble back to a bottom of drumas drumrotates. Bafflesmay be mounted to drumsuch that bafflesrotate with drumduring operation of dryer appliance.

Rear wallof drumis rotatably supported within cabinetby a suitable bearing. Rear wallcan be fixed or can be rotatable. Rear wallmay include, for instance, a plurality of holesthat receive hot air that has been heated by a heater assembly. The heater assemblymay include a heat pump, heating element, or refrigerant-based heater assembly. For instance, heater assemblymay include a plurality of heater devices, such as depicted distributed along the duct. Moisture laden, heated air is drawn from drumby an air handlerthat draws air through chamberof drumwhen motorrotates a fan assembly. In particular, ambient air, shown schematically via arrow, enters heater assemblydue to air handlerurging relatively cool ambient airinto the heater assembly. Such cool airis selectively heated through the heater assemblyand is provided as heated air, shown schematically via arrowto chamber.

In various embodiments further described herein, heater assemblymay be non-activated or deactivated such that air,provided to the chamberis substantially similar to ambient air(i.e., unheated). Air handlerdraws heated airthrough a duct, such as a back duct or first duct, to drum. Heated airenters through the plurality of holesand flows through chamber, such as depicted schematically via arrow. Within chamber, heated aircan accumulate moisture (e.g., from damp articles disposed within chamber). In turn, air handlerdraws the moisture laden heated air, depicted schematically via arrow. Airenters through an outlet duct. Ductmay form a front duct or second duct including a lint filter(e.g., a screen filter) configured to collect lint during drying. Heated airpasses through ductenclosing filter, which traps lint particles. More specifically, filtermay include a screen, mesh, other material to capture lint in the air flow. The location of lint filters in applianceas shown inis provided by way of example only, and other locations may be used as well. As shown, lint filteris readily accessible by a user of the appliance. Air then passes through air handlerto an exhaust duct, such as depicted schematically via arrows.

A doorprovides for closing or accessing drumthrough opening. According to exemplary embodiments, a window (not shown) in doorpermits viewing of chamberwhen dooris in the closed position, e.g., during operation of dryer appliance. Dooralso includes a handle that, e.g., a user may pull when opening and closing door. Further, although dooris illustrated as mounted to front panel, it should be appreciated that doormay be mounted to another side of cabinetor any other suitable support according to alternative embodiments. Dryer appliancemay further include a latch assembly(see) that is mounted to cabinetand/or doorfor selectively locking doorin the closed position. Latch assemblymay be desirable, for example, to ensure only secured access to chamberor to otherwise ensure and verify that dooris closed during certain operating cycles or events.

In some embodiments, one or more selector inputs, such as knobs, buttons, touchscreen interfaces, etc., may be provided or mounted on a cabinet(e.g., on a user interface panel) and are communicatively coupled with an appliance controller. Controllermay also be communicatively coupled with various operational components of dryer appliance, such as motor, fan assembly, and/or components of heater assembly. In turn, signals generated in controllerdirect operation of motor, fan assembly, or heater assemblyin response user inputs to selector inputs. Controllermay be configured as an analog controller or timer including timer stages and sensing stages described herein.

Referring to, dryer applianceincludes a heater control thermostatpositioned in thermal communication with air at the duct. The heater control thermostat includes a bi-metal thermostat (e.g., a first bi-metal thermostat) having a heater control set point relative to which the heater assemblyoperates to provide heated airto the chamber. The heater control set point includes a temperature threshold or set point at or above which a circuit opens or closes, such as to allow or inhibit heater control signals for generating heat, or various heat loads, based on embodiments of the method for cycle control described herein.

Dryer applianceincludes an outlet sensorpositioned in communication with air at an outlet portion of duct, such as outlet duct. In some embodiments, the outlet sensorincludes an outlet thermostat including a bi-metal thermostat (e.g., a second bi-metal thermostat) having a sensing temperature set point. The sensing temperature set point includes a temperature threshold or set point at or above which a circuit opens or closes, such as to inhibit heater control signals to discontinue heat generation based on embodiments of the method for cycle control described herein.

In still some embodiments, the outlet sensorincludes a conductivity sensor configured to measure or determine an ability for a solution to conduct an electrical current. For instance, the outlet sensorincluding a conductivity sensor may be configured to determine a presence of ions in the air at the outlet duct, such as may be indicative of moisture in the air at the outlet duct. The outlet sensorincluding the conductivity sensor may include a conductivity threshold or target at or above which a circuit opens or closes, such as to inhibit heater control signals to discontinue heat generation based on embodiments of the method for cycle control described herein.

provides an exemplary flow diagram of a timer stagefor the controller.provides an exemplary flow diagram of a sensing stagefor the controller.provides another exemplary flow diagram of a sensing stagefor the controller.provides an exemplary flow diagram of a dryer cyclefor the controller.

Referring now to, a flowchart outlining steps of a method for cycle control at a dryer appliance is provided (hereinafter, “method”). Controllerare configured based on steps of method. However, it should be appreciated that other embodiments of the dryer appliancemay include embodiments of a controller based on steps of methoddescribed herein.

Methodatincludes positioning a heater control thermostat (e.g., thermostat) in thermal communication with air at an inlet portion of a duct (e.g., duct) in fluid communication with a chamber (e.g., chamber) for receiving laundry articles (e.g., laundry articles LA) for drying. The heater control thermostat includes a first bi-metal thermostat having a heater control set point relative to which a heater assembly (e.g., heater assembly) operates to provide heated air (e.g., heated air) to the chamber.

Referring to, timer stageis configured to operate the heater assembly for a pre-determined heating period and based on the heater control set point at the heater control thermostat. For instance, with commencement of the timer stage and timer set, the heater assembly and operably coupled heater control thermostat generate a heat load to generate heated air (e.g., heated air). Heated airis provided to the chamberfor a pre-determined amount of time (i.e., the heating period). After completion of the heating period, the timer stage ends and the control circuit proceeds to the next stage.

In some embodiments, the control circuit includes a plurality of timer stages. In still some embodiments, each timer stage may include a respective heater assembly, or respective heat load, and respective heater control thermostat and heater control set point. For instance, an embodiment of the control circuit including two (2) timer stages may include two (2) respective heater control thermostats and respective heater control set points. The heater control thermostats may include heater control set points different from one another (i.e., different target temperatures for the heater assembly). Additionally, or alternatively, each timer stage may include respective heating periods over which heated air is provided to the chamber based on the heater set point.

Methodincludes atpositioning an outlet sensor (e.g., outlet sensor) in communication with air at an outlet portion of duct (e.g., duct). In some embodiments, the outlet sensor includes a second bi-metal thermostat having a sensing temperature set point, such as described herein regarding dryer appliance. In still some embodiments, the outlet sensor includes a conductivity sensor having a conductivity threshold, such as described herein regarding dryer appliance.

Methodincludes atoperably coupling the heater control thermostat to the heater assembly to selectively output heat based on the heater control set point and a pre-determined heating period.

Methodincludes atoperably coupling the outlet thermostat to the heater assembly to operate the heater assembly until the sensing temperature set point is met after operating the heater assembly for the heating period based on the heater control set point. The outlet thermostat disables heat generation at the heater assembly after the sensing temperature set point is met.

Referring to, sensing stageis configured to operate the heater assembly based on the sensing temperature set point. For instance, after completion of one or more timer stages, sensing stagemay commence to generate heated air for an un-determined period of time based on an outlet temperature of air exiting the chamber (e.g., airexiting chamber). After the outlet temperature of airmeets the sensing temperature set point, the heater assembly discontinues generating heat load for generating heated air.

Referring to, sensing stageis configured to operate the heater assembly based on the conductivity threshold or target. For instance, after completion of one or more timer stages, sensing stagemay commence to generate heated air for an un-determined period of time based on a presence of ions in air exiting the chamber (e.g., airexiting chamber). After the conductivity of airmeets the conductivity threshold, the heater assembly discontinues generating heat load for generating heated air.

Referring to, an exemplary dryer cyclemay include a heater control circuit having a plurality of timer stages in serial operable arrangement. A sensing stage is positioned in serial operable arrangement after the timer stages. In some embodiments, a timer stage may include a cooldown cycle during which heat generation at the heater assembly is disabled.

Embodiments of the dryer appliance, controller, and methodprovided herein include a control circuit including a timer stage and a sensing stage. The timer stage allows or discontinues heater control thermostats or sensors and associated heaters for the respective stage and advances the timer until the timer reaches the next stage. During the sensing stage, the timer allows or discontinues heater control thermostats and heaters relative to the sensing stage. However, the timer advances when the sensing temperature set point of the outlet thermostat is triggered or when the conductivity threshold of the conductivity sensor is triggered. Timer stages and sensing stages can be arranged into the timer (e.g., controller) in any desired order to form the control circuit such as described herein. The timer can allow or discontinue any desired heater control thermostats, sensors, or heaters, such as to generate desired heat loads for producing various heat and conditions at air entering the chamber.

It should be appreciated that dryer cycles and stages described herein may include generating and transmitting signals for commencing and discontinuing operation of the drum, such as signals for operating a motor to rotate the drumto tumble clothing articles at one or more speeds. Embodiments of the timer stage and sensing stage provided herein may include corresponding signals for continuous or intermittent tumbling of laundry articles.

Embodiments of the dryer applianceand methodprovided herein may provide dryer cycle control without requiring electronic controller software. Embodiments provided herein may provide fine tuning of heat output out and mitigate or eliminate over-drying and under-drying of laundry articles, reduce energy consumption, and improve overall dryer cycle performance. Embodiments of the controllermay avoid configurations including, or requiring, processors, memory devices, or systems for executing software controls, while facilitating dryer cycle control and adjustment. For instance, embodiments of the controllermay be configured as an analog controller. Embodiments provided herein may avoid configurations including, or requiring, processors, memory devices, or systems for executing software controls, providing for methods, controllers, and dryer appliances having analog cycle control.

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.