Patent Publication Number: US-11655583-B2

Title: Method for drying articles

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/225,581, filed on Dec. 19, 2018, now U.S. Pat. No. 10,816,265, issued Oct. 27, 2020, which is a continuation of U.S. patent application Ser. No. 15/369,967, filed Dec. 6, 2016, now U.S. Pat. No. 10,184,718, issued Jan. 22, 2019, which is a continuation of U.S. patent application Ser. No. 13/943,918, filed Jul. 17, 2013, now U.S. Pat. No. 9,541,330, issued Jan. 10, 2017, the contents of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Dielectric heating is the process in which a high-frequency alternating electric field heats a dielectric material, such as water molecules. At higher frequencies, this heating is caused by molecular dipole rotation within the dielectric material, while at lower frequencies in conductive fluids, other mechanisms such as ion-drag are more important in generating thermal energy. 
     Microwave frequencies are typically applied for cooking food items and are considered undesirable for drying laundry articles because of the possible temporary runaway thermal effects random application of the waves in a traditional microwave. Radio frequencies and their corresponding controlled and contained e-field are typically used for drying of textile material. 
     When applying an RF electronic field (e-field) to a wet article, such as a clothing material, the e-field may cause the water molecules within the e-field to dielectrically heat, generating thermal energy which effects the rapid drying of the articles. 
     BRIEF DESCRIPTION OF THE INVENTION 
     One aspect of the invention is directed to a method to dry an article in a dryer drum with a radio frequency (RF) applicator having a first partial anode ring disposed adjacent to the lowest gravitational point of the drum, a second anode element, a first partial cathode ring disposed adjacent to the lowest gravitational point of the drum opposite the first partial anode ring, and a second cathode element. The method comprises electrically coupling an electrode of the RF applicator to the first partial anode ring and another electrode of the RF applicator to the first partial cathode ring. Capacitively coupling the first partial anode ring to the second anode element, and the first partial cathode ring to the second cathode element. Capacitively coupling the second anode element to the second cathode element. Energizing the RF applicator to energize the first partial anode ring and the first partial cathode ring, thereby inducing energization between the first partial anode ring and the second anode, and between the first partial cathode ring and the second cathode respectively to generate a field of electromagnetic radiation (e-field) between the second anode and second cathode elements. Liquid in the article residing within the e-field is dielectrically heated by the field to effect a drying of the article. 
     Another aspect of the invention is directed to an article treatment appliance to dry an article according to a predetermined cycle of operation. The article treatment appliance has a first partial anode ring partially encircling a first radial segment of a drum and disposed adjacent to the lowest gravitational point of the drum. A first partial cathode ring partially encircling a second radial segment of the drum disposed adjacent to the lowest gravitational point of the drum and opposite the first partial anode ring. A second anode element and a second cathode element. The first partial anode ring is capacitively coupled with the second anode element and operably separated by a dielectric. The first partial cathode ring is capacitively coupled with the second cathode element and operably separated by a dielectric. The second anode element is capacitively coupled with the second cathode element and operably spaced from each other, and a radio frequency (RF) applicator with an electrode electrically coupled with the first partial anode ring and another electrode electrically coupled with the first partial cathode ring. The RF applicator is operable to selectively energize the first partial anode ring and the first partial cathode ring in a radio frequency spectrum. The energization of the first partial anode ring and first partial cathode ring induces energization between the first partial anode ring and the second anode, between the first partial cathode ring and the second cathode, and between the second anode and the second cathode to generate a field of electromagnetic radiation in the radio frequency spectrum between the second anode and the second cathode, operable to dielectrically heat liquid within the article. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG.  1    is a schematic perspective view of the laundry treating apparatus in accordance with the first embodiment of the invention. 
         FIG.  2    is a partial sectional view taken along line  2 - 2  of  FIG.  1    in accordance with the first embodiment of the invention. 
         FIG.  3    is a schematic perspective view of an axially-exploded laundry treating apparatus with a rotating drum configuration, in accordance with the second embodiment of the invention. 
         FIG.  4    is a partial sectional view taken along line  4 - 4  of  FIG.  3    showing the assembled configuration of the drum and anode/cathode elements, in accordance with the second embodiment of the invention. 
         FIG.  5    is a partial sectional view showing an alternate assembled configuration of the drum and anode/cathode elements, in accordance with the third embodiment of the invention. 
         FIG.  6    is a schematic perspective view of an axially-exploded laundry treating apparatus with a rotating drum configuration having integrated anode/cathode rings, in accordance with the fourth embodiment of the invention. 
         FIG.  7    is a schematic perspective view of an embodiment where the laundry treating appliance is shown as a clothes dryer incorporating the drum of the second, third, and fourth embodiments. 
     
    
    
     DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     While this description may be primarily directed toward a laundry drying machine, the invention may be applicable in any environment using a radio frequency (RF) signal application to dehydrate any wet article. 
       FIG.  1    is a schematic illustration of a laundry treating appliance  10  according to the first embodiment of the invention for dehydrating one or more articles, such as articles of clothing. As illustrated in  FIG.  1   , the laundry treating appliance  10  has a structure that includes conductive elements, such as a first cathode element  12  and a second cathode element  14 , and an opposing first anode element  16 , a second anode element  18 , in addition to a first non-conductive laundry support element  20 , an optional second non-conductive support element  23 , and an RF applicator  22 . 
     The second cathode element  14  further includes a first comb element  24  having a first base  26  from which extend a first plurality of teeth  28 , and the second anode element  18  includes a second comb element  30  having a second base  32  from which extend a second plurality of teeth  34 . The second cathode and second anode elements  14 ,  18  are fixedly mounted to the first supporting element  20  in such a way as to interdigitally arrange the first and second pluralities of teeth  28 ,  34 . The second cathode and second anode elements  14 ,  18  may be fixedly mounted to the first support element  20  by, for example, adhesion, fastener connections, or laminated layers. Additionally, the first cathode and anode elements  12 ,  16  are shown fixedly mounted to the second support element  23  by similar mountings. Alternative mounting techniques may be employed. 
     At least a portion of either the first or second support elements  20 ,  23  separates an at least partially aligned first cathode and second cathode elements  12 ,  14 . As illustrated, the elongated first cathode element  12  aligns with the substantially rectangular first base  26  portion of the second cathode element  14 , through the first support element  20  and second support element  23 , with the support elements  20 ,  23  separated by an optional air gap  70 . Similarly shown, the elongated first anode element  16  at least partially aligns with the substantially rectangular second base  32  portion of the second anode element  18  through a portion of the first support element  20  and second support element  23 , with the support elements  20 ,  23  separated by an air gap  70 . The aligned portions of the first and second cathode elements  12 ,  14  are oppositely spaced, on the supporting elements  20 ,  23 , from the aligned portion of the first and second anode elements  16 ,  18 . 
     The RF applicator  22  may be configured to generate a field of electromagnetic radiation (e-field) within the radio frequency spectrum between outputs electrodes and may be electrically coupled between the first cathode element  12  and the first anode element  16  by conductors  36  connected to at least one respective first anode and cathode contact point  38 ,  40 . One such example of an RF signal generated by the RF applicator  22  may be 13.56 MHz. The generation of another RF signal, or varying RF signals, is envisioned. 
     Microwave frequencies are typically applied for cooking food items. However, their high frequency and resulting greater dielectric heating effect make microwave frequencies undesirable for drying laundry articles. Radio frequencies and their corresponding lower dielectric heating effect are typically used for drying of laundry. In contrast with a conventional microwave heating appliance, where microwaves generated by a magnetron are directed into a resonant cavity by a waveguide, the RF applicator  22  induces a controlled electromagnetic field between the cathode and anode elements  12 ,  14 ,  16 ,  18 . Stray-field or through-field electromagnetic heating provides a relatively deterministic application of power as opposed to conventional microwave heating technologies where the microwave energy is randomly distributed (by way of a stirrer and/or rotation of the load). Consequently, conventional microwave technologies may result in thermal runaway effects or arcing that are not easily mitigated when applied to certain loads (such as metal zippers etc.). Stated another way, using a water analogy where water is analogous to the electromagnetic radiation, a microwave acts as a sprinkler while the above-described RF applicator  22  is a wave pool. It is understood that the differences between microwave ovens and RF dryers arise from the differences between the implementation structures of applicator vs. magnetron/waveguide, which renders much of the microwave solutions inapplicable for RF dryers. 
     Each of the conductive cathode and anode elements  12 ,  14 ,  16 ,  18  remain at least partially spaced from each other by a separating gap, or by non-conductive segments, such as by the first and second support elements  20 ,  23 , or by the optional air gap  70 . The support elements  20 ,  23  may be made of any suitable low loss, fire retardant materials, or at least one layer of insulating materials that isolates the conductive cathode and anode elements  12 ,  14 ,  16 ,  18 . The support elements  20 ,  23  may also provide a rigid structure for the laundry treating appliance  10 , or may be further supported by secondary structural elements, such as a frame or truss system. The air gap  70  may provide enough separation to prevent arcing or other unintentional conduction, based on the electrical characteristics of the laundry treating apparatus  10 . 
     Turning now to the partial sectional view of  FIG.  2   , taken along line  2 - 2  of  FIG.  1    in accordance with the first embodiment of the invention, the first support element  20  may further include a non-conductive bed  42  wherein the bed  42  may be positioned above the interdigitally arranged pluralities of teeth  28 ,  34  (not shown in  FIG.  2   ). The bed  42  further includes a substantially smooth and flat upper surface  44  for receiving wet laundry. The bed  42  may be made of any suitable low loss, fire retardant materials that isolate the conductive elements from the articles to be dehydrated. 
     The aforementioned structure of the laundry treating appliance  10  operates by creating a first capacitive coupling between the first cathode element  12  and the second cathode element  14  separated by at least a portion of the at least one support element  20 ,  23 , a second capacitive coupling between the first anode element  16  and the second anode element  18  separated by at least a portion of the at least one support element  20 ,  23 , and a third capacitive coupling between the pluralities of teeth  28 ,  34  of the second cathode element  14  and the second anode element  18 , at least partially spaced from each other. During drying operations, wet laundry to be dried may be placed on the upper surface  44  of the bed  42 . During, for instance, a predetermined cycle of operation, the RF applicator  22  may be continuously or intermittently energized to generate an e-field between the first, second, and third capacitive couplings which interacts with liquid in the laundry. The liquid residing within the e-field will be dielectrically heated to effect a drying of the laundry. 
     Many other possible configurations in addition to that shown in the above figures are contemplated by the present embodiment. For example, one embodiment of the invention contemplates different geometric shapes for the laundry treating appliance  10 , such as substantially longer, rectangular appliance  10  where the cathode and anode elements  12 ,  14 ,  16 ,  18  are elongated along the length of the appliance  10 , or the longer appliance  10  includes a plurality of cathode and anode element  12 ,  14 ,  16 ,  18  sets. In such a configuration, the upper surface  44  of the bed  42  may be smooth and slightly sloped to allow for the movement of wet laundry or water across the laundry treating appliance  10 , wherein the one or more cathode and anode element  12 ,  14 ,  16 ,  18  sets may be energized individually or in combination by one or more RF applicators  22  to dry the laundry as it traverses the appliance  10 . Alternatively, the bed  42  may be mechanically configured to move across the elongated laundry treating appliance  10  in a conveyor belt operation, wherein the one or more cathode and anode element  12 ,  14 ,  16 ,  18  sets may be energized individually or in combination by one or more RF applicators  22  to dry the laundry as it traverses the appliance  10 . 
     Additionally, a configuration is envisioned wherein only a single support element  20  separates the first cathode and anode elements  12 ,  16  from their respective second cathode and anode elements  14 ,  18 . This configuration may or may not include the optional air gap  70 . In another embodiment, the first cathode element  12 , first anode element  16 , or both elements  12 ,  16  may be positioned on the opposing side of the second support element  23 , within the air gap  70 . In this embodiment, the air gap  70  may still separate the elements  12 ,  16  from the first support element  20 , or the elements  12 ,  16  may be in communication with the first support element  20 . 
     Furthermore,  FIG.  3    illustrates an alternative laundry treating appliance  110  according to a second embodiment of the invention. The second embodiment may be similar to the first embodiment; therefore, like parts will be identified with like numerals increased by 100, with it being understood that the description of the like parts of the first embodiment applies to the second embodiment, unless otherwise noted. A difference between the first embodiment and the second embodiment may be that laundry treating appliance  110  may be arranged in a drum-shaped configuration rotatable about a rotational axis  164 , instead of the substantially flat configuration of the first embodiment. 
     In this embodiment, the support element includes a drum  119  having a non-conducting outer drum  121  having an outer surface  160  and an inner surface  162 , and may further include a non-conductive element, such as a sleeve  142 . The sleeve  142  further includes an inner surface  144  for receiving and supporting wet laundry. The inner surface  144  of the sleeve  142  may further include optional tumble elements  172 , for example, baffles, to enable or prevent movement of laundry. The sleeve  142  and outer drum  121  may be made of any suitable low loss, fire retardant materials that isolate the conductive elements from the articles to be dehydrated. While a sleeve  142  is illustrated, other non-conductive elements are envisioned, such as one or more segments of non-conductive elements, or alternate geometric shapes of non-conductive elements. 
     As illustrated, the conductive second cathode element  114 , and the second anode elements  118  are similarly arranged in a drum configuration and fixedly mounted to the outer surface  143  of the sleeve  142 . In this embodiment, the opposing first and second comb elements  124 ,  130  include respective first and second bases  126 ,  132  encircling the rotational axis  164 , and respective first and second pluralities of teeth  128 ,  134 , interdigitally arranged about the rotational axis  164 . 
     The laundry treating appliance  110  further includes a conductive first cathode element comprising at least a partial cathode ring  112  encircling a first radial segment  166  of the drum  119  and an axially spaced opposing conductive first anode element comprising at least a partial anode ring  116  encircling a second radial segment  168  of the drum  119 , which may be different from the first radial segment  166 . As shown, at least a portion of the drum  119  separates the at least partially axially-aligned cathode ring  112  and the first base  126  portion of the second cathode elements  114 . Similarly, at least a portion of the drum  119  separates the at least partially axially-aligned anode ring  116  and the second base  132  portion of the second anode element  118 . Additionally, this configuration aligns the first base  126  with the first radial segment  166 , and the second base  132  with the second radial segment  168 . Alternate configurations are envisioned where only at least a portion of the drum  119  separates the cathode or anode rings  112 ,  116  from their respective first and second bases  126 ,  132 . 
     The RF applicator  22  may be configured to generate a field of electromagnetic radiation (e-field) within the radio frequency spectrum between outputs electrodes and may be electrically coupled between the cathode ring  112  and the anode ring  116  by conductors  36  connected to at least one respective cathode and anode ring contact point  138 ,  140 . 
     Each of the conductive cathode and anode elements  112 ,  114 ,  116 ,  118  remain at least partially spaced from each other by a separating gap, or by non-conductive segments, such as by the outer drum  121 . The outer drum  121  may be made of any suitable low loss, fire retardant materials, or at least one layer of insulating materials that isolates the conductive cathode and anode elements  112 ,  114 ,  116 ,  118 . The drum  119  may also provide a rigid structure for the laundry treating appliance  110 , or may be further supported by secondary structural elements, such as a frame or truss system. 
     As shown in  FIG.  4   , the assembled laundry treating appliance  110 , according to the second embodiment of the invention, creates a substantially radial integration between the sleeve  142 , second cathode and anode elements  114 ,  118  (cathode element not shown), and drum  119  elements. It may be envisioned that additional layers may be interleaved between the illustrated elements. Additionally, while the cathode ring  112  and anode ring  116  are shown offset about the rotational axis for illustrative purposes, alternate placement of each ring  112 ,  116  may be envisioned. 
     The second embodiment of the laundry treating appliance  110  operates by creating a first capacitive coupling between the cathode ring  112  and the second cathode element  114  separated by at least a portion of the drum  119 , a second capacitive coupling between the anode ring  116  and the second anode element  118  separated by at least a portion of the drum  119 , and a third capacitive coupling between the pluralities of teeth  128 ,  134  of the second cathode element  114  and the second anode element  118 , at least partially spaced from each other. 
     During drying operations, wet laundry to be dried may be placed on the inner surface  144  of the sleeve  142 . During a cycle of operation, the drum  119  may rotate about the rotational axis  164  at a speed at which the tumble elements  172  may enable, for example, a folding or sliding motion of the laundry articles. During rotation, the RF applicator  22  may be off, or may be continuously or intermittently energized to generate an e-field between the first, second, and third capacitive couplings which interacts with liquid in the laundry. The liquid interacting with the e-field located within the inner surface  144  will be dielectrically heated to effect a drying of the laundry. 
     Many other possible configurations in addition to that shown in the above figures are contemplated by the present embodiment. For example, in another configuration, the cathode and anode rings  112 ,  116  may encircle larger or smaller radial segments, or may completely encircle the drum  119  at first and second radial segments  166 ,  168 , as opposed to just partially encircling the drum  119  at a first and second radial segments  166 ,  168 . In yet another configuration, the first and second bases  126  and  132  and the first and second plurality of teeth  128 ,  134  may only partially encircle the drum  119  as opposed to completely encircling the drum  119 . In even another configuration, the pluralities of teeth  28 ,  34 ,  128 ,  134  may be supported by slotted depressions in the support element  20  or sleeve  142  matching the teeth  28 ,  34 ,  128 ,  134  for improved dielectric, heating, or manufacturing characteristics of the appliance. In another configuration, the second cathode and anode elements  114 ,  118  may only partially extend along the outer surface  143  of the sleeve  142 . 
     In an alternate operation of the second embodiment, the RF applicator  22  may be intermittently energized to generate an e-field between the first, second, and third capacitive couplings, wherein the intermittent energizing may be related to the rotation of the drum  119 , or may be timed to correspond with one of aligned capacitive couplings, tumbling of the laundry, or power requirements of the laundry treating appliance  110 . In another alternate operation of the second embodiment, the RF applicator  22  may be moving during the continuous or intermittent energizing of the e-field between the first, second, and third capacitive couplings. For instance, the RF applicator  22  may rotate about the rotational axis  164  at similar or dissimilar periods and directions as the drum  119 . In yet another alternate operation of the second embodiment, the drum may be rotationally stopped or rotationally slowed while the RF applicator  22  continuously or intermittently energizes to generate an e-field between the first, second, and third capacitive couplings. 
       FIG.  5    illustrates an alternative assembled laundry treating appliance  210 , according to the third embodiment of the invention. The third embodiment may be similar to the first and second embodiments; therefore, like parts will be identified with like numerals increased by 200, with it being understood that the description of the like parts of the first and second embodiment applies to the third embodiment, unless otherwise noted. A difference between the first embodiment and the second embodiment may be that laundry treating appliance  210  may be arranged in a drum-shaped configuration, wherein the outer drum  121  is separated from the second anode element  118  by a second drum element  223  and an air gap  270 . 
     Additionally, the same anode ring  116  and cathode ring  112  (not shown) are elongated about a larger radial segment of the drum  119 . Alternatively, the cathode ring  112 , anode ring  116 , or both rings  112 ,  116  may be positioned on the opposing side of the outer drum  121 , within the air gap  270 . In this embodiment, the air gap  270  may still separate the elements  112 ,  116  from the second drum element  223 , or the elements  112 ,  116  may be in communication with the second drum element  223 . The operation of the third embodiment is similar to that of the second embodiment. 
       FIG.  6    illustrates an alternative laundry treating appliance  310  according to a fourth embodiment of the invention. The fourth embodiment may be similar to the second or third embodiments; therefore, like parts will be identified with like numerals beginning with  300 , with it being understood that the description of the like parts of the first, second, and third embodiments apply to the fourth embodiment, unless otherwise noted. A difference between the prior embodiments and the fourth embodiment may be that first cathode and anode elements include cathode and anode rings  312 ,  316  assembled at axially opposite ends of the drum  319 . This configuration may be placed within a housing, for instance, a household dryer cabinet (not shown). 
     In this embodiment, the assembled cathode and anode rings  312 ,  316  are electrically isolated by, for example, at least a portion of the drum  319  or air gap (not shown). In this sense, the laundry treating appliance  310  retains the first and second capacitive couplings of the second embodiment. 
     The RF applicator  22  may be configured to generate a field of electromagnetic radiation (e-field) within the radio frequency spectrum between outputs electrodes and may be electrically coupled between the cathode ring  312  and the anode ring  316  by conductors  36  connected to at least one respective cathode and anode ring contact point  338 ,  340 . In this embodiment, the cathode and anode ring contact points  338 ,  340  may further include direct conductive coupling through additional components of the dryer cabinet supporting the rotating drum  319 , such as via ball bearings (not shown). Other direct conductive coupling through additional components of the dryer cabinet may be envisioned. 
     The fourth embodiment of the laundry treating appliance  310  operates by creating a first capacitive coupling between the cathode ring  312  and the second cathode element  114  separated by at least a portion of the drum  319  or air gap, a second capacitive coupling between the anode ring  316  and the second anode element  118  separated by at least a portion of the drum  319  or air gap. During rotation, the RF applicator  22  may be off, or may be continuously or intermittently energized to generate an e-field between the first, second, and third capacitive couplings which interacts with liquid in the laundry. The liquid interacting with the e-field located within the inner surface  144  will be dielectrically heated to effect a drying of the laundry. 
       FIG.  7    illustrates an embodiment where the appliance is a laundry treating appliance, such as a clothes dryer  410 , incorporating the drum  119 ,  219 ,  319  (illustrated as drum  119 ), which defines a treating chamber  412  for receiving laundry for treatment, such as drying. The clothes dryer comprises an air system  414  supplying and exhausting air from the treating chamber, which includes a blower  416 . A heating system  418  is provided for hybrid heating the air supplied by the air system  414 , such that the heated air may be used in addition to the dielectric heating. The heating system  418  may work in cooperation with the laundry treating appliance  110 , as described herein. 
     Many other possible embodiments and configurations in addition to those shown in the above figures are contemplated by the present disclosure. For example, alternate geometric configurations of the first and second pluralities of teeth are envisioned wherein the interleaving of the teeth are designed to provide optimal electromagnetic coupling while keeping their physical size to a minimum. Additionally, the spacing between the pluralities of teeth may be larger or smaller than illustrated. 
     The embodiments disclosed herein provide a laundry treating appliance using RF applicator to dielectrically heat liquid in wet articles to effect a drying of the articles. One advantage that may be realized in the above embodiments may be that the above described embodiments are able to dry articles of clothing during rotational or stationary activity, allowing the most efficient e-field to be applied to the clothing for particular cycles or clothing characteristics. A further advantage of the above embodiments may be that the above embodiments allow for selective energizing of the RF applicator according to such additional design considerations as efficiency or power consumption during operation. 
     Additionally, the design of the anode and cathode may be controlled to allow for individual energizing of particular RF applicators in a single or multi-applicator embodiment. The effect of individual energization of particular RF applicators results in avoiding anode/cathode pairs that would result in no additional material drying (if energized), reducing the unwanted impedance of additional anode/cathode pairs and electromagnetic fields inside the drum, and an overall reduction to energy costs of a drying cycle of operation due to increased efficiencies. Finally, reducing unwanted fields will help reduce undesirable coupling of energy into isolation materials between capacitive coupled regions. 
     Moreover, the capacitive couplings in embodiments of the invention allow the drying operations to move or rotate freely without the need for physical connections between the RF applicator and the pluralities of teeth. Due to the lack of physical connections, there will be fewer mechanical couplings to moving or rotating embodiments of the invention, and thus, an increased reliability appliance. 
     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 have 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.