Laundry drying machine and control method of laundry drying machine

Abstract

The present invention relates to a laundry drying machine including a cabinet, a drum rotatably installed in the cabinet to accommodate articles to be dried, and an electric field generator spaced apart from the drum and generating an electric field inside the drum when powered. The electric field generator includes a positive electrode spaced apart from the drum, fixed to the cabinet and applying an electric field to the articles to be dried accommodated in the drum, a power supply unit supplying power to the positive electrode, and a matcher provided in the cabinet and matching a source impedance with a load side impedance. When reflectivity of the electric field exceeds a predetermined ratio, a rotational speed of the drum is reduced to reduce the reflectivity of the electric field, thus having an effect of preventing damage to devices such as the matcher due to reflected waves.

Description

Technical Field

[0001] This invention relates to a laundry drying machine and a control method for the laundry drying machine, and more specifically to a laundry drying machine capable of generating high frequency and drying objects by means of dielectric heating, and a control method for the laundry drying machine. Background Technology

[0002] In recent years, garment processing equipment has been developed that performs a drying cycle to remove moisture from clothes. Traditional garment processing equipment supplies hot air to the drums containing the clothes to dry them, thereby greatly shortening the drying time and sterilizing and disinfecting the clothes.

[0003] However, this type of dryer uses heat transferred from heated air to raise the temperature of the water contained in the clothes, causing the water to evaporate. Since the heat is transferred from air with a low specific heat to water with a high specific heat, the actual temperature rise of the water is not significant compared to the temperature of the heated air, and its drying performance is low compared to the energy consumed.

[0004] In addition, in order for the water in the clothes to reach the evaporation temperature, the temperature in the drum must reach a high temperature of over 100 degrees Celsius. Therefore, there is a problem that the high temperature air comes into contact with the clothes, causing the clothes to deteriorate and be damaged.

[0005] Furthermore, such dryers are equipped with an exhaust system to discharge the moisture evaporated from the clothes to the outside of the dryer. In this case, due to the continuous discharge of heated air, the temperature inside the drum inevitably decreases, and the heater's operating time increases, thus increasing energy consumption and drying time.

[0006] To address this problem, a high-frequency (RF) clothes dryer has been developed that vibrates and heats the moisture absorbed by the clothes.

[0007] In high-frequency (RF) clothing dryers, in order to solve the overheating problem when using RF power for a long time, and in order to heat the objects to be dried evenly by mixing them together, there is a process where the drum rotates at only 50 rpm when there is no RF power supply.

[0008] However, during this process, the items to be dried rotate inside the drum using centrifugal force and fall due to gravity. Therefore, the items shrink due to this mechanical force.

[0009] US Patent 9200402B discloses a dielectric heating type clothes dryer.

[0010] In this type of dryer, the negative and positive electrodes are rotatably arranged, and when RF power (RF power) of a predetermined frequency is applied, an electric field is generated to heat the moisture contained in the clothing.

[0011] On the other hand, since both the negative and positive electrodes are arranged in a rotating manner, the roller must be essentially stopped in order to form a constant electric field.

[0012] However, when the internal temperature of the object to be dried rises rapidly as described above, a problem arises: localized overheating occurs inside the object. In particular, when the object to be dried is dyed synthetic fiber, color transfer can occur due to localized overheating. In the case of synthetic fibers, color transfer may occur if the temperature exceeds 50 degrees Celsius.

[0013] Meanwhile, US Patent 9447537B discloses a clothes dryer that uses electrodes to electrically heat the items to be dried.

[0014] In the above invention, the positive electrode is fixed, while the roller, which serves as the negative electrode, is arranged in a rotatable state.

[0015] In the above invention, RF power is applied to the positive electrode when the drying process begins, while the drum stops. Impedance matching is easy when the drum stops, and continuous heating is feasible after impedance matching, which is very effective for rapidly heating the moisture contained in the object to be dried.

[0016] However, even in this case, there is a problem: the internal temperature of the object to be dried rises rapidly, causing localized overheating.

[0017] In this case, to prevent localized overheating inside the clothing, the RF current supply is stopped after heating the items to be dried for 90 seconds, and the roller is rotated for 5 seconds to mix the items to be dried.

[0018] However, in this method, since the heat inside the object to be dried is not fully dissipated before dielectric heating is performed again, there is a problem that the internal temperature of the object to be dried continuously rises as the drying cycle proceeds.

[0019] Furthermore, in this method, the matcher must perform impedance matching in less than 7 seconds in order to supply RF power again, and power consumption may occur during this process, which increases the overall drying time.

[0020] Furthermore, when heating occurs after sufficient internal heat has been released, the energy and time required for reheating with dielectric material are both significant, resulting in a decrease in drying efficiency.

[0021] In addition, during the mixing of items to be dried, the items may fall due to the centrifugal force of the drum, and the clothes may shrink.

[0022] On the other hand, Korean patent KR 2018-0085201A discloses a dryer that simultaneously performs RF drying and hot air drying.

[0023] In such a dryer, the negative and positive electrodes are rotatably arranged, and when RF power of a predetermined frequency is applied, an electric field is generated to heat the moisture contained in the clothing. Therefore, in order to create a constant electric field, the rollers must be substantially stopped.

[0024] Correspondingly, the dryer will also stop the drum to heat it and repeat the operation of rotating the drum to prevent the clothes from overheating in certain areas, which would increase energy consumption and drying time.

[0025] This dryer can perform hot air drying while the drum is rotating, thus addressing the issue of increased drying time. However, when both dielectric heating and hot air drying are performed simultaneously, the power consumption can be very high.

[0026] Furthermore, while the inside of the object to be dried is heated by dielectric heating, the outside of the object is also heated by hot air drying, which can damage the object.

[0027] Therefore, it is necessary to develop a technology that can minimize energy consumption while shortening drying time.

[0028] On the other hand, Korean Patent Publication KR 2007-0056287A discloses a hot air dryer. In this dryer, the drum rotates at a constant speed of 50 rpm to uniformly supply hot air to the object to be dried during the drying process.

[0029] In this configuration, the object to be dried is rotated by centrifugal force and moves upward within the drum, then falls under the influence of gravity. While increasing the contact area with hot air as the object falls improves drying performance, a problem arises: the object shrinks. Summary of the Invention

[0030] Technical issues

[0031] The present invention aims to improve upon the problems of conventional clothes dryers and clothes dryer control methods as described above. The purpose of the present invention is to provide a clothes dryer and clothes dryer control method that can prevent color transfer in the object to be dried.

[0032] Another object of the present invention is to provide a clothes dryer and a method for controlling the clothes dryer, which can prevent localized overheating of the items to be dried.

[0033] Another object of the present invention is to provide a clothes dryer and a control method for the clothes dryer, which can heat the items to be dried contained in the drum while the drum rotates in a dielectric heating type dryer.

[0034] Another object of the present invention is to provide a clothes dryer and a control method for the clothes dryer, which can improve the drying efficiency of a dielectric heating type dryer that requires a large amount of energy and time to perform dielectric heating.

[0035] Another object of the present invention is to provide a clothes dryer and a method for controlling the clothes dryer, which can minimize energy consumption during the drying process.

[0036] Another object of the present invention is to provide a clothes dryer and a control method for the clothes dryer, which can prevent color transfer of the items to be dried regardless of the size of the clothes dryer.

[0037] Another object of the present invention is to provide a clothes dryer and a method for controlling the clothes dryer, which can prevent damage to equipment such as the matching device caused by reflected waves generated by the rotation of the drum.

[0038] Another object of the present invention is to provide a clothes dryer and a control method for the clothes dryer, which can save the time and energy required for impedance matching.

[0039] Another object of the present invention is to provide a clothes dryer and a control method for the clothes dryer, which can prevent the items to be dried from falling during the mixing process.

[0040] Another object of the present invention is to provide a clothes dryer and a method for controlling the clothes dryer, which can reduce the shrinkage of the items to be dried and provide a shrinkage degree similar to that of natural drying.

[0041] Technical solution

[0042] To achieve the above objectives, the clothes dryer according to the present invention may include: a housing; a drum rotatably mounted in the housing to accommodate items to be dried; an electric field generator spaced apart from the drum and generating an electric field inside the drum when powered; and an exhaust pipe that discharges air from inside the drum.

[0043] An electric field generator may include a positive electrode spaced apart from the drum, fixed to the housing, and apply an electric field to the object to be dried contained in the drum.

[0044] The electric field generator may also include a power supply unit that supplies power to the positive electrode.

[0045] The electric field generator may also include a matching unit, which is housed in the housing and matches the power supply impedance to the load-side impedance.

[0046] In this configuration, the drum can rotate when power is applied to the positive electrode.

[0047] When power is applied to the positive electrode, the drum rotates at a predetermined drying speed, and when power is stopped being applied to the positive electrode, the drum rotates at a predetermined agitation speed.

[0048] The drying speed can be lower than the stirring speed.

[0049] The positive electrode can be formed in an arc shape, which surrounds a predetermined angular range with the rotation axis of the roller as the origin.

[0050] In this scenario, while electricity is applied to the positive electrode, the roller can move at an angle (rad) formed by the positive electrode. Rotation speeds of 7 rpm or higher and below 7 rpm.

[0051] The roller may include: a roller body formed in a cylindrical shape and containing an object to be dried therein; and a notch part connected to the roller body and bent inward from the outer peripheral surface of the roller body.

[0052] The notch may include: a connecting portion formed in an annular shape and connected to the roller body; and a positive electrode receiving portion that bends inward in a radial direction at the connecting portion and forms a space for accommodating the positive electrode.

[0053] The positive electrode can be spaced apart from the notch at a predetermined interval and can be formed into an arc shape concentric with the notch.

[0054] The matching device can continuously match the power supply impedance with the load impedance while the drum rotates at the drying speed.

[0055] A clothes dryer according to an embodiment of the present invention may further include: a drum motor that provides driving force to rotate the drum; and a control unit disposed inside the housing and controlling the drum motor and the electric field generator.

[0056] In this configuration, the control unit can operate both the matcher and the drum motor simultaneously.

[0057] The control unit can measure the temperature of the item to be dried and operate the roller motor to keep the temperature of the item to be dried at 50 degrees Celsius or lower.

[0058] The roller may also include at least one lifter disposed on the inner circumferential surface of the roller body and formed to protrude toward the center of the roller body.

[0059] When an electric current is applied to the positive electrode, the lift can come into contact with the object to be dried at least once.

[0060] To achieve the above objectives, in a control method for a clothes dryer comprising a drum containing the object to be dried and a positive electrode spaced apart from the drum (which is used to generate an electric field in the drum), the control method for a clothes dryer according to the present invention may include: a drying step, namely, applying power to the positive electrode and rotating the drum at a preset drying speed for a preset drying time; and an agitation step, namely, cutting off the power application to the positive electrode and rotating the drum at a preset agitation speed for a preset agitation time.

[0061] The drying speed and stirring speed in the drying step can be different.

[0062] The drying speed during the drying step can be lower than the stirring speed.

[0063] During the drying process, the drum can be rotated, and the matching device can be operated to continuously match the power supply impedance and the load-side impedance.

[0064] In the drying step, the drying time can be more than 80 seconds and less than 100 seconds.

[0065] During the stirring step, the stirring time can be more than 3 seconds and less than 7 seconds.

[0066] The control method for the clothes dryer according to the present invention may further include a load sensing step, namely, rotating the drum before the drying step to sense the load of the item to be dried.

[0067] The drying speed in the drying step can be lower than the speed of the roller in the load sensing step.

[0068] In the drying step, the drying speed can be set to be proportional to the angle range set by the arc-shaped positive electrode with the rotation axis of the drum as the origin.

[0069] In the drying step, the drying speed can be set at an angle (rad) with the arc-shaped positive electrode and the rotation axis of the drum as the origin. Times or more.

[0070] During the drying process, the drying speed can be above 0 rpm or below 7 rpm.

[0071] To achieve the above objectives, the clothes dryer according to the present invention may include: a housing; a drum rotatably mounted in the housing to accommodate items to be dried; and an electric field generator spaced apart from the drum, which generates an electric field within the drum when powered.

[0072] The electric field generator may include: a positive electrode, spaced apart from the drum and fixed to the housing, which applies an electric field to the object to be dried contained in the drum; a power supply unit that applies power to the positive electrode; and a matching unit disposed in the housing for matching the power supply impedance with the load-side impedance.

[0073] With power no longer applied to the positive electrode, the drum is rotated at a preset stirring speed, which can be greater than 0 and less than 50 rpm.

[0074] In this case, the value obtained by multiplying the radius of the drum by the square of the agitation speed (rad / s) can be 0.27 times or less the magnitude of gravitational acceleration.

[0075] When power is applied to the positive electrode, the drum can rotate at a preset drying speed.

[0076] The stirring speed can be greater than the drying speed.

[0077] The stirring speed can be greater than 0 and less than 30 rpm.

[0078] Accordingly, when the drum rotates at a preset agitation speed, the object to be dried can slide along the inner circumferential surface of the drum.

[0079] To achieve the above objectives, in a control method comprising a drum containing the items to be dried and a positive electrode spaced apart from the drum to generate an electric field in the drum, the control method of the clothes dryer according to the present invention may include: a drying step, namely, applying power to a fixed positive electrode and rotating the drum; and an agitation step, namely, cutting off the power applied to the positive electrode and rotating the drum.

[0080] During the agitation step, the drum rotates at a preset agitation speed, which can be greater than 0 and less than 30 rpm.

[0081] The square of the agitation speed can be set to be inversely proportional to the radius of the drum.

[0082] The value obtained by multiplying the radius of the drum by the square of the agitation speed (rad / s) can be 0.27 times the magnitude of gravitational acceleration or less.

[0083] During the agitation step, the drum is rotated for a preset agitation time, which can be 3 seconds or more, and 7 seconds or less.

[0084] During the drying process, the drum can rotate at a preset drying speed, and the drying speed can be less than the agitation speed.

[0085] During the drying step, the drying speed can be greater than 0 and less than 7 rpm.

[0086] The control method for the clothes dryer according to the present invention may further include a load sensing step, namely, rotating the drum before the drying step to sense the load of the object to be dried.

[0087] In this case, during the load sensing step, the drum can rotate at an agitation speed.

[0088] To achieve the above objectives, the clothes dryer according to the present invention may include: a housing; a drum rotatably mounted in the housing to accommodate items to be dried; an electric field generator spaced apart from the drum and generating an electric field within the drum when electricity is applied; and an exhaust duct for discharging air from the drum.

[0089] The electric field generator may include: a positive electrode, spaced apart from the drum and fixed to the housing, which applies an electric field to the object to be dried contained in the drum; a power supply unit that supplies power to the positive electrode; and a matching unit disposed in the housing for matching the power supply impedance with the load-side impedance.

[0090] In this situation, the rotational speed of the drum may decrease when the reflectivity of the electric field exceeds a predetermined ratio.

[0091] When the reflectivity of the electric field is less than or equal to a predetermined ratio, the electric field generator can increase the power applied to the positive electrode.

[0092] When the reflectivity of the electric field exceeds a predetermined ratio, the rotational speed of the drum can be reduced by 10%.

[0093] When power is applied to the positive electrode, the electric field generator can apply power corresponding to the preset start-up power. When the reflectivity of the electric field is less than or equal to a predetermined ratio, the electric field generator can apply power corresponding to 20% of the preset drying power.

[0094] When the power applied to the positive electrode is equivalent to 20% of the drying power, and the reflectivity of the electric field is less than or equal to a predetermined ratio, the electric field generator can apply power equivalent to 50% of the drying power to the positive electrode.

[0095] When the power applied to the positive electrode is equivalent to 50% of the drying power, and the reflectivity of the electric field is less than or equal to a predetermined ratio, the electric field generator can apply power equivalent to 100% of the drying power to the positive electrode.

[0096] When a preset drying power is applied to the positive electrode, and the reflectivity of the electric field reflected from the object to be dried is less than or equal to a predetermined ratio, the drum can maintain this rotational speed.

[0097] When power is applied to the positive electrode, the drum can rotate.

[0098] To achieve the above objectives, in a control method for a clothes dryer comprising a drum containing the items to be dried and a positive electrode spaced apart from the drum (which is used to generate an electric field in the drum), the control method for a clothes dryer according to the present invention may include: a drying step, namely, applying power to a fixed positive electrode and rotating the drum; and an agitation step, namely, cutting off the power application to the positive electrode and rotating the drum.

[0099] During the drying step, when the reflectivity of the electric field exceeds a predetermined ratio, the rotational speed of the drum can be reduced, and when the reflectivity of the electric field is less than or equal to the predetermined ratio, the power applied to the positive electrode can be increased.

[0100] The drying process may include: a drying initiation step, which involves applying a preset starting power to the positive electrode and rotating the drum at a preset starting speed; and a rotation holding step, which involves applying a preset drying power to the positive electrode and maintaining the rotation speed of the drum.

[0101] In the drying step, when the reflectivity of the electric field exceeds a predetermined ratio after the drying process begins, the rotational speed of the drum can be reduced.

[0102] The drying step may also include a first power increase step, i.e., after the drying entry step, when the reflectivity of the electric field is less than or equal to a predetermined ratio, the power applied to the positive electrode is increased to 20% of the drying power.

[0103] In the drying step, after the first power increase step, when the reflectivity of the electric field exceeds a predetermined ratio, the rotational speed of the drum can be reduced.

[0104] The drying step may also include a second power increase step, i.e., after the first power increase step, when the reflectivity of the electric field is less than or equal to a predetermined ratio, the power applied to the positive electrode is increased to 50% of the drying power.

[0105] In the drying step, after the second power increase step, when the reflectivity of the electric field exceeds a predetermined ratio, the rotational speed of the drum can be reduced.

[0106] The drying step may also include a third power increase step, which is that after the second power increase step, when the reflectivity of the electric field is less than or equal to a predetermined ratio, the power applied to the positive electrode is increased to the drying power.

[0107] In the drying step, after the third power increase step, when the reflectivity of the electric field exceeds a predetermined ratio, the rotational speed of the drum can be reduced.

[0108] Beneficial effects

[0109] As described above, according to the clothing dryer and the control method of the clothing dryer of the present invention, by keeping the internal temperature of the item to be dried below 50 degrees, the effect of preventing color transfer in the item to be dried can be achieved.

[0110] In addition, it has the effect of preventing localized overheating of the items to be dried when they are mixed by the rotation of the drum.

[0111] Furthermore, the advantage is that in a dielectric heating dryer, the material to be dried can be heated while the drum rotates at low speed with the positive electrode fixed.

[0112] In dielectric heating dryers, which require a lot of energy and time for dielectric heating, the advantage is that the drying efficiency can be improved by rotating the drum, even when power is applied to the positive electrode.

[0113] Furthermore, the advantage lies in minimizing energy consumption by reducing the drum speed to the maximum extent possible during the drying process and agitation calibration.

[0114] Furthermore, it has the effect of preventing color transfer of items to be dried by providing a minimum rotational speed of the roller that is proportional to the angle around the positive electrode and the roller, regardless of the size of the clothes dryer.

[0115] Furthermore, it has the effect of reducing the reflectivity of the electric field by controlling the rotational speed of the drum and the RF power, thus preventing damage to equipment such as the matching device due to reflected waves.

[0116] Furthermore, since the drying process can be started immediately without the need for separate impedance matching time, it saves the time and energy required for impedance matching.

[0117] Furthermore, the advantage is that, during the mixing of items to be dried, by setting the rotational speed range of the drum, the items to be dried can slide along the inner circumferential surface of the drum without falling.

[0118] In addition, it has the following effect: by preventing the object to be dried from falling, it reduces the shrinkage of the object to be dried due to mechanical force. Attached Figure Description

[0119] Figure 1 This is a view used to explain the appearance of a clothes dryer according to an embodiment of the present invention.

[0120] Figure 2 yes Figure 1 A view taken from another angle.

[0121] Figure 3 It is along Figure 2 A cross-sectional view taken along the centerline AA.

[0122] Figure 4 It is along Figure 2 A cross-sectional view taken along the center line BB.

[0123] Figure 5 yes Figure 4 A magnified view of part A.

[0124] Figure 6 This is a view of a clothes dryer according to an embodiment of the present invention, showing the front panel, top panel, and side panel in a disassembled state.

[0125] Figure 7 This is a rear view of a clothes dryer according to an embodiment of the present invention, with the rear panel removed.

[0126] Figure 8 This is a front view of a clothes dryer according to an embodiment of the present invention, with the casing disassembled.

[0127] Figure 9 This is a front view of a partially disassembled portion of a clothes dryer according to an embodiment of the present invention.

[0128] Figure 10 This is a front view used to explain the electric field generator in a clothes dryer according to an embodiment of the present invention.

[0129] Figure 11 This is a perspective view showing an electric field generator in a clothes dryer according to an embodiment of the present invention.

[0130] Figure 12 This is a block diagram used to explain the control configuration scheme in a clothes dryer according to an embodiment of the present invention.

[0131] Figure 13 This is a flowchart illustrating a control method for a clothes dryer according to an embodiment of the present invention.

[0132] Figure 14 It is a graph showing the temperature change of the items to be dried in a conventional dielectric heating type clothes dryer.

[0133] Figure 15 This is a graph showing the temperature change of the item to be dried when the control method of the clothes dryer according to an embodiment of the present invention is applied.

[0134] Figure 16 This is a flowchart illustrating the process of controlling the rotational speed of the drum and the RF power for impedance matching during the drying process in a control method for a clothes dryer according to an embodiment of the present invention.

[0135] Figure 17 This is a graph showing the difference in shrinkage rate over time when a control method for a clothes dryer according to an embodiment of the present invention is applied. Detailed Implementation

[0136] In the following, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0137] Since the present invention can have various variations and embodiments, specific embodiments are illustrated in the accompanying drawings and will be described in detail in the specific implementation details. This is not intended to limit the invention to the specific embodiments, but should be understood to include all modifications, equivalents, and substitutions within the spirit and scope of the invention.

[0138] In describing this invention, terms such as "first" and "second" may be used to describe various components, but these components may not be limited by these terms. The terms are used only to distinguish one component from another. For example, without departing from the scope of this invention, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component.

[0139] The term “and / or” can include a combination of multiple related listed items or any one of multiple related listed items.

[0140] When a component is described as being "connected" or "in contact" with another component, it may be directly connected or in contact with the other component, but it can be understood that other components may exist between the two. On the other hand, when a component is described as being "directly connected" or "directly in contact" with another component, it can be understood that there are no other components between the two.

[0141] The terminology used in this application is for describing specific embodiments only and is not intended to limit the invention. Singular expressions may include plural expressions unless the context clearly specifies otherwise.

[0142] In this application, terms such as “comprising” or “having” are intended to specify the presence of features, numbers, steps, operations, components, parts or combinations thereof described in the specification, and are to be understood as not precluding the possibility of the presence or addition of one or more other features or numbers, steps, operations, components, parts or combinations thereof.

[0143] Unless otherwise defined, all terms used herein (including technical or scientific terms) may have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms such as those defined in common dictionaries may be interpreted as having the meaning consistent with the relevant technical context, and should not be interpreted in an ideal or overly formal sense unless expressly defined in this application.

[0144] Furthermore, the following embodiments are provided to explain more completely to those skilled in the art. For clarity, the shape and size of the elements in the figures may be exaggerated.

[0145] Figure 1 The diagram shows a view for explaining the appearance of a clothes dryer according to an embodiment of the present invention. Figure 2 Show Figure 1 A view taken from another angle. Figure 3 Show along Figure 2 A sectional view taken along the centerline AA. Figure 4 Show along Figure 2 A sectional view taken along the center line BB. Figure 5 Show Figure 4 A magnified view of part A. Figure 6 This view shows a clothes dryer according to an embodiment of the present invention with the front panel, top panel, and side panels removed. Figure 7 A rear view showing a clothes dryer according to an embodiment of the present invention with the rear panel removed. Figure 8 A front view showing the housing of a clothes dryer according to an embodiment of the present invention is shown with the housing disassembled.

[0146] like Figures 1 to 8As shown, the housing 10 (which forms the outer body of the clothes dryer 1) includes: a front panel 11 forming the front surface; a rear panel 12 forming the rear surface; a pair of side panels 13 forming the side surfaces; an upper panel 14 forming the upper surface; and a lower panel 15 forming the lower surface.

[0147] The front panel 11 may be provided with: an inlet 111 configured to communicate with the roller 20 described below; and a door 112 rotatably connected to the housing 10 to open and close the inlet 111.

[0148] Control panel 117 is located on front panel 11.

[0149] The control panel 117 may include: an input unit 118 for receiving control commands from the user; a display unit 119 for outputting information such as control commands selectable by the user; and a main control unit (not shown) for controlling commands used to perform the operation of the clothes dryer 1.

[0150] On the other hand, the input unit 118 can be configured to include: a power supply request unit for requesting power to the clothes dryer; a process input unit for allowing the user to select the desired process from multiple processes; an execution request unit for requesting the start of the process selected by the user, etc.

[0151] The display unit 119 can be configured to include at least one of a display panel capable of outputting characters and / or numbers, and a speaker capable of outputting voice signals and sounds. Users can easily grasp the current management status, remaining time, and other conditions through the information output by the display unit 119.

[0152] Inside the housing 10 are: a roller 20, which is rotatably disposed and provides space for holding clothes (items to be dried); a duct section 30, which supplies air to the roller 20 and exhausts air from inside the roller 20; and an electric field generator 40, which generates an electric field inside the roller 20.

[0153] The roller 20 may include: a cylindrical roller body 21 having an open front surface; a first support 22 rotatably supported on the front surface of the roller body 21 inside the housing 10; and a second support 23 rotatably supported on the rear surface of the roller body 21.

[0154] The internal space of the roller 20 serves as a drying chamber, where drying takes place. Alternatively, the roller 20 of the present invention can also serve as the negative electrode of a capacitor.

[0155] The first support portion 22 may be configured to include: a first fixed body 22a, fixed to the interior of the housing 10; and a roller inlet 22b, configured to pass through the first fixed body 22a to connect the inlet 111 and the interior of the roller body 21.

[0156] The first fixed body 22a may be provided with an air outlet 22c that communicates with the pipe section 30.

[0157] like Figure 2 As shown, the air outlet 22c is a channel that allows the internal air of the roller body 21 to move to the pipe section 30, and can be configured as a through hole that is configured to pass through the first fixed body 22a.

[0158] The second support 23 is configured to include a second fixed body 23a fixed to the interior of the housing 10.

[0159] An air inlet 23b is formed in the second support portion 23. The air inlet is configured to pass through the second fixed body 23a and communicate with the interior of the roller body 21 and the interior of the housing 10.

[0160] The outer peripheral surface of the roller body 21 may include one or more recesses 24 that are recessed in the circumferential direction. In this case, the positive electrode 41, which will be described below, may be spaced apart from each other in the recesses 24 at predetermined intervals.

[0161] The specific structure of roller 20 will be described in detail below.

[0162] The cylindrical roller body 21 can be rotated by means of various types of drive units 50.

[0163] For example, Figure 2 One embodiment is shown, wherein the drive unit 50 includes a roller motor 51 fixed inside the housing 10, a pulley 52 rotated by the roller motor 51, and a belt 53 connecting the peripheral surface of the pulley 52 and the peripheral surface of the roller body 21.

[0164] In this case, the side panel 13 may be provided with rollers R for rotatably supporting the circumferential surface of the roller body 21.

[0165] However, the present invention is not limited thereto; direct-drive type drive units are also applicable, wherein the roller motor 51 is directly connected to the roller to rotate the roller without passing through pulleys and belts, which also falls within the scope of the present invention. For convenience, the following description will be based on the illustrated embodiment of drive unit 50.

[0166] The piping section 30 includes an exhaust pipe 31 connected to the air outlet 22c and a supply pipe 32 connected to the air inlet 23b.

[0167] The exhaust duct 31 serves as a channel to exhaust air from inside the drum body 21 to the outside of the housing 10. Correspondingly, water vapor generated from the items to be dried can be exhausted to the outside of the housing 10 by the fluid force of the circulating fan 33.

[0168] The exhaust pipe 31 includes an intake pipe 31a, a fan housing 31b, and an exhaust pipe 31c.

[0169] The suction pipe 31a is configured to communicate with the air outlet 22c and can serve as a channel to guide air from inside the roller 20 to the outside. Specifically, the suction pipe 31a can provide a flow path formed downward from the air outlet 22c in the direction of gravity. For example, the suction pipe 31a can be a pipe with a flat shape in the front-to-back direction. In this case, the lower surface of the suction pipe 31a can be inclined at a predetermined angle relative to the ground. In this configuration, water that has passed through the air outlet 22c and condensed on the inner surface of the suction pipe 31a can flow downward by its own weight and be collected, and discharged to the outside of the clothes dryer 1 by means of the flow force of the circulating fan 33, as will be described below. Therefore, moisture can be prevented from accumulating inside the suction pipe 31a, thereby preventing the growth of bacteria and the like.

[0170] The fan housing 31b is formed to communicate with the intake pipe 31a and is cylindrical to accommodate the impeller 33a of the circulating fan 33, as will be described below. Thus, air passing through the intake pipe 31a can be flowed by the rotation of the impeller 33a and discharged to the outside of the clothes dryer 1.

[0171] One side of the exhaust pipe 31c can be connected to the fan housing 31b, while the other side can be disposed outside the clothes dryer 1 via the rear panel 12. With this configuration, the air discharged from the fan housing 31b can be discharged to the outside of the clothes dryer 1 through the exhaust pipe 31c.

[0172] Furthermore, the duct section 30 may include a circulating fan 33 to move air along the exhaust duct 31. The circulating fan 33 is configured to include: an impeller 33a disposed in the exhaust duct 31; and an impeller motor 33b to rotate the impeller 33a and provide flow power to the air moving along the exhaust duct 31. For example, the impeller 33a may be housed in the fan housing 31b of the exhaust pipe 31c to provide flow power to the air.

[0173] The supply pipe 32 can be used as a channel to guide air from outside the drum body 21 into the drum body 21. The supply pipe 32 can communicate with the air inlet 23b so that the interior of the housing 10 is in communication with the drum body 21. With this configuration, when the circulating fan 33 is driven to generate negative pressure inside the drum body 21, air from outside the drum body 21 passes through the supply pipe 32, through the air inlet 23b, and can be introduced into the interior of the drum body 21.

[0174] Meanwhile, the air flowing inside the drum 20 can be indoor air, heated air, or a combination of both.

[0175] The electric field generator 40 can be any device capable of generating an electric field inside the drum 20. For example, the electric field generator 40 can be a device that uses the electric field generated between the positive and negative electrodes to cause water molecules to vibrate for heating (dielectric heating) and evaporation.

[0176] Specifically, the electric field generator 40 may include a positive electrode 41 that forms an electric field relative to the roller 20, which is a negative electrode.

[0177] The specific shape of the positive electrode 41 will be described below.

[0178] The electric field generator 40 may include a matching unit 42 connected to the positive electrode 41 to supply a current of a predetermined frequency to the positive electrode 41. The matching unit 42 may be supported by being coupled to the lower panel 15.

[0179] Matching unit 42 can be electrically connected to the positive electrode 41 to adjust the inductance or capacitance to tune it to a predetermined frequency. Furthermore, matching unit 42 can match the high-frequency power supply impedance to the load-side impedance. Matching unit 42 may include a variable inductor and a variable capacitor. As for the detailed construction of matching unit 42, any means known in the art can be used, and therefore a detailed description of its construction will be omitted.

[0180] Meanwhile, the matching unit 42 may include a heat sink (not shown) and a cooling fan. With this configuration, the air inside the housing 10 can recover heat as it passes through the heat sink, and the cooling fan can introduce heated air into the housing 10, and the heated air can be reintroduced into the roller 20 to support the drying of the items to be dried.

[0181] The electric field generator 40 may include a power supply unit 43 electrically connected to the matching unit 42 for power supply.

[0182] The power supply unit 43 is electrically connected to the matching unit 42 to supply a constant frequency current to the positive electrode 41. Thus, when power is applied to the positive electrode 41, an electric field can be generated in the drum 20.

[0183] In this embodiment, the power supply unit (power supply unit) 43 may refer to an RF power device (RF power supply). The roller 20 is connected to the fixed-frequency power supply unit 43 via a matching connector 42 and the control unit 100 to measure appropriate power, drying, load size, and drying end time settings, and to execute the drying process. In this case, the preferred operating frequency of the power supply 21 is in the range of 1MHz to 50MHz.

[0184] When the object to be dried is tumbled and / or stopped, RF power can be applied through the power supply unit 43.

[0185] The drying process of the object to be dried will be described below.

[0186] Furthermore, the clothes dryer 1 according to the present invention may also include a filter unit F for removing foreign matter, such as lint and dust generated during the drying process of clothes and other garments.

[0187] As for the detailed construction of the filter unit F, any device known in the art can be used, and a detailed description of its construction will be omitted.

[0188] The electric field generator 40 can be directly controlled by the control unit 100.

[0189] The control unit 100 is configured to control the operation of the clothes dryer 1 based on user input applied through the input unit 118. The control unit 100 may consist of a printed circuit board and components mounted on the printed circuit board. When the user inputs control commands through the input unit 118, such as selecting the clothes processing process or the operation of the clothes dryer 1, the control unit 100 can control the operation of the clothes dryer 1 according to a preset algorithm.

[0190] The specific control functions of the control unit 100 in this invention will be described below.

[0191] Figure 9 This is a front view of a partially disassembled portion of the notch in a clothes dryer according to an embodiment of the present invention. Figure 10 This is a front view used to explain the electric field generator in a clothes dryer according to an embodiment of the present invention. Figure 11 This is a perspective view used to explain the electric field generator in a clothes dryer according to an embodiment of the present invention.

[0192] Reference Figure 4 , Figure 5 and Figures 9 to 11 The structure of the positive electrode 41 and the drum 20 in the clothes dryer 1 according to an embodiment of the present invention is described.

[0193] The roller 20 may include a roller body 21, a first support portion 22, a second support portion 23, a notch portion 24, a lifter 25, and a grounding electrode 26. To avoid repetition of the above description, a detailed description of the first support portion 22 and the second support portion 23 will be omitted.

[0194] The drum body 21 is formed into a hollow shape, so that the objects to be dried can be accommodated in the internal space. In other words, the drum body 21 can be formed into a cylindrical or annular shape.

[0195] The notch 24 is formed in an annular shape and is connected to the roller body 21 for overall rotation.

[0196] In this case, multiple roller bodies 21 are manufactured and can be connected to or integrally formed with the recess 24.

[0197] Specifically, the notch 24 can be formed by radially retracting a portion of the outer peripheral surface of the cylindrical roller body 21.

[0198] Specifically, the notch 24 may include: a connecting portion 24a, which is formed in an annular shape and connected to the roller body 21; and a positive electrode receiving portion 24b, which is bent inward in the radial direction at the connecting portion 24a and forms a space for accommodating the positive electrode 41.

[0199] Therefore, a portion of the notch 24 forming the roller 20 can have a reduced diameter. In other words, when viewed from the outside of the roller 20, the notch 24 can be in the form of a groove that is recessed inward in the circumferential direction on the outer peripheral surface of the roller body 21.

[0200] The roller body 21 can be alternately arranged with the recess 24. For example, three roller bodies 21 and two recesses 24 can be provided, and one recess 24 can be provided between two roller bodies 21. In other words, two recesses 24 can be provided at a predetermined distance from each other. However, the number of recesses 24 and the number of roller bodies 21 are not limited to this and can be changed according to the overall size of the roller 20.

[0201] On the other hand, the notch 24 can be provided with an air inlet 24c so that the interior of the roller body 21 is connected to the interior of the housing 10. Thus, air from outside the roller 20 can be introduced into the roller 20 through the air inlet 24c.

[0202] Specifically, when the circulating fan 33 is driven and the air inside the drum 20 is drawn into the exhaust pipe 31, a negative pressure can be generated inside the drum 20, and the air outside the drum 20 can be forcibly introduced into the hollow (partial) part of the drum 20 through the air inlet 24c of the notch 24.

[0203] This airflow can quickly remove water vapor evaporated from the object to be dried. Furthermore, the airflow causes moisture inside the object to evaporate, further removing moisture. Additionally, when electricity is applied to the positive electrode 41 and the matching device 42 to generate heat, they can be cooled to extend their lifespan.

[0204] Simultaneously, at least one lifting device 25 can be provided on the inner circumferential surface of the drum 20. For example, three lifting devices 25 can be provided at fixed intervals (120 degrees). The lifting devices 25 can be fixedly connected to the inner circumferential surface of the drum body 21 and the inner surface of the recess 24, and can be formed in a shape that protrudes from the inner circumferential surface of the drum body 21 and the inner surface of the recess 24 toward the rotation axis of the drum 20. The lifting devices 25 can be configured to contact the objects to be dried contained in the drum 20. With this configuration, when the drum 20 rotates, the objects to be dried can rotate together with the drum 20 to a predetermined angle, while being supported by the lifting devices 25, and then fall to the lower side by their own weight. In this process, the objects to be dried can be naturally mixed. In other words, the objects to be dried can be agitated by the lifting devices 25, the tumbling motion of the objects to be dried can be enhanced, and the objects to be dried can be uniformly heated when oscillating around the rotation axis of the drum 20.

[0205] Therefore, the effect is that it can suppress the bundling that occurs on the object to be dried by the lift 25.

[0206] On the other hand, the rotating conductive roller 20 is connected to the ground electrode 26 by direct rotation or capacitive coupling. For example, the ground electrode 25 can be selectively activated or continuously connected only when RF power is applied.

[0207] The connection between the grounding electrode and the roller body 21 can be continuously initiated during movement. Alternatively, the connection between the grounding electrode and the roller body 21 can be selectively initiated during rotation or when stopped.

[0208] The positive electrode 41 may include a positive electrode plate 41a, an air channel hole 41b, a support frame 41c, a connecting frame 41d, and a fixing panel 41e.

[0209] The positive electrode plate 41a can be an arc-shaped plate with a predetermined angle cut from the annular shape, or an annular plate. For example, the positive electrode plate 41a can be arranged on a concentric circle relative to the central axis of the roller body 21, and can be an arc-shaped plate formed within a range of 120 degrees with the rotation axis of the roller body 20 as the origin. In other words, the positive electrode 41 can have an annular shape cut into one-third of its length.

[0210] Meanwhile, in this embodiment, the positive electrode plates 41a are configured as a pair and arranged to face each other, but are not limited thereto.

[0211] Furthermore, both ends of the positive electrode plate 41a may be formed to extend outward in the radial direction to be fixedly connected to the connection frame 41d, which will be described below.

[0212] Multiple air passage holes 41b can be formed in the positive electrode plate 41a, and these air passage holes can be formed to correspond to the positions of the air inlets 24a in the recess 24. With this configuration, air from outside the roller 20 can flow into the roller 20.

[0213] Specifically, when the circulating fan 33 is driven and the air inside the drum 20 is drawn into the exhaust pipe 31, a negative pressure can be generated inside the drum 20, and the air outside the drum 20 can be forcibly introduced into the hollow (partial) part of the drum 20 through the air passage hole 41b.

[0214] Furthermore, it has the effect of cooling the overheated positive electrode plate 41a when air passes through the air channel hole 41b through the positive electrode plate 41a.

[0215] The support frame 41c can be formed to extend downward from the positive electrode plate 41a in the direction of gravity. The support frame 41c can contact the upper outer peripheral surface of the exhaust pipe 31c provided on the lower side, and the positive electrode plate 41a can be supported by the support frame 41c.

[0216] The connecting frame 41d can be configured to connect a pair of positive electrode plates 41a to each other. Specifically, the connecting frame 41d is formed as a flat strip with one end bent, and the pair of positive electrode plates 41a are respectively fixedly connected to two planes at the bent end. In this case, the bending angle of the connecting frame 41d is formed to correspond to the shape of the two ends of the positive electrode plates 41a.

[0217] Two connecting frames 41d can be provided to correspond to the positions of the two ends of the positive electrode plate 41a. With this configuration, both ends of the positive electrode plate 41a can be fixed to the connecting frames 41d.

[0218] The fixing panel 41e can be formed in the shape of a flat plate, and its two ends in the longitudinal direction can be respectively connected to the connecting frame 41d. Thus, the fixing panel 41e is used to fix the positive electrode plate 41a to maintain a constant distance. In other words, multiple positive electrode plates 41a can be maintained at a predetermined distance by the fixing panel 41e, and can maintain a predetermined distance from the roller 20 even when the roller 20 is rotating.

[0219] The positive electrode 41 can be disposed below the roller 20 and can be spaced apart from the roller body 21 and the notch 24 at a predetermined distance.

[0220] The positive electrode 41 can be positioned to correspond to the position of the recess 24 formed on the outer peripheral surface of the roller body 21.

[0221] With this configuration, when the object to be dried is placed inside the drum 20, the positive electrode 41 can apply a sufficient electric field to the object to be dried, even if it is concentrated at the bottom of the drum body.

[0222] Furthermore, the positive electrode 41 can be disposed in the space of the recess 24 formed inwardly based on the outer peripheral surface of the roller body 21. For example, the positive electrode 41 can be disposed corresponding to two recesses 24 formed therebetween with a predetermined interval. In this case, the two positive electrodes 41 can be fixed to the pair of fixed panels 41e in order to maintain the distance between them.

[0223] With this arrangement, the positive electrode 41 and the outer peripheral surface of the roller body 21, which serves as the negative electrode, can be alternately arranged along the axial direction.

[0224] Meanwhile, the width and perimeter of the positive electrode 41, as well as their proportions, can be changed.

[0225] The positive electrode 41 can be made of bare metal or insulating metal. An insulator can be coated on the positive electrode 41. Conversely, the roller 20 can be made of conductive material (i.e., metal) or insulating material coated with a conductive layer.

[0226] Meanwhile, the notch 24 of the roller 20 is spaced apart from the positive electrode 41. Therefore, the positive electrode 41 is fixed in space, while the roller 20 can rotate. The roller 20 can rotate freely clockwise and counterclockwise around the axis of rotation. Furthermore, since the roller 20 does not contact the positive electrode 41, its rotational speed can be freely changed.

[0227] In other words, the positive electrode 41 and the roller 20 can be configured to rotate relative to each other. In this case, the object (clothes) to be dried can be placed between the fixed positive electrode 41 and the rotating conductive roller 20.

[0228] For example, the positive electrode 41 can be disposed in the space formed in the recess 24, and can be disposed in a radial direction perpendicular to the outer peripheral surface of the roller body 21. Thus, the object to be dried can be located in the space in which the positive electrode 41 and the outer peripheral surface of the roller body 21 are disposed perpendicularly to each other.

[0229] With this configuration, when RF power is applied through the power supply unit 43, the electric field between the positive electrode 41 and the roller 20 electrically penetrates the notch 24, and the electric field can be formed in the internal space of the roller 20. While vibrating with the help of the electric field, the moisture contained in the object to be dried can be heated and evaporated.

[0230] More specifically, the positive electrode 41 can generate an RF (radio frequency) capacitive coupling effect by maintaining the electric field required for drying the object in relation to the roller 20. In other words, a relatively low RF frequency is preferably used to minimize the parasitic capacitance generated in the roller 20, which acts as the negative electrode. For example, frequencies of 10 MHz or higher and 15 MHz or lower can be used for the positive electrode 41. In this case, to improve energy efficiency, the object to be dried is preferably placed close to the roller 20 and the positive electrode 41. Meanwhile, the parasitic capacitance is independent of the capacitance of the object itself and can be defined as any capacitance between the positive electrode 41 and the roller 20.

[0231] An alternating current can be generated on a capacitor circuit through a semiconductive (wet) load of the object to be dried, and a single-frequency RF-generated current is applied between at least one fixed positive electrode 41 and a rotating drum 20, thereby enabling dielectric heating of the object to be dried.

[0232] Figure 12 This is a block diagram used to explain the control configuration in a clothes dryer according to an embodiment of the present invention.

[0233] Reference Figures 1 to 3 and Figure 12 The structure used for control in this invention will be described below.

[0234] First, the control unit 100 can be signal- or electrically connected to the input unit 118 and the display unit 119. Thus, when a user inputs a control command to the input unit 118, the input unit 118 can transmit information about the control command to the control unit 100, and the control unit 100 can store this information. Furthermore, the control unit 100 can transmit information about the user-input control command to the display unit 119 to display this information to the user. Additionally, the control unit 100 can transmit information such as the load on the object to be dried, the drying progress status, and the drying time required to the display unit, so that the display unit 119 can notify the user.

[0235] Furthermore, the control unit 100 is connected to the sensor unit 101 and the door switch unit 102. The sensor unit 101 can measure the temperature of the object to be dried, the airflow inside the roller 20, etc. The door switch unit 102 can notify the control unit 100 whether the door 112 is open or closed relative to the roller 20, and can also notify the control unit 100 whether the door 112 is locked or unlocked when it is closed. In addition, the control unit 100 can transmit control signals to the door switch unit 102 to selectively open and close the door 112, and can also transmit control signals to selectively lock and unlock the door when it is closed.

[0236] Furthermore, the control unit 100 can be connected to the roller motor 51. Thus, the control unit 100 can drive the roller motor 51 to rotate or stop the roller 20, control the rotational speed of the roller 20, and change the rotational direction of the roller 20.

[0237] Furthermore, the rotational speed of the roller 20 can be tracked by the control unit 100. This is to determine the optimal power adjustment during the drying cycle, as water gradually evaporates from the object to be dried.

[0238] Furthermore, the control unit 100 can be connected to the impeller motor 33b. Thus, the control unit 100 can rotate or stop the circulating fan 33 by driving the impeller motor 33b, and can control the rotational speed of the circulating fan 33. Correspondingly, the control unit 100 can control the amount of air discharged from the drum 20.

[0239] Furthermore, the control unit 100 can control the electric field generator 40. In other words, the control unit 100 can control the power supply unit 43 to apply power to the positive electrode 41, and can cut off the power application. Additionally, the control unit 100 can control the matching device 42 to match the source impedance with the load impedance. With this configuration, the control unit 100 can apply a stable electric field to the object to be dried to dielectrically heat the object.

[0240] Specifically, the control unit 100 can control the real-time variation of at least one of RF power, impedance Z, RF reflection coefficient, VSWR, etc., in order to deliver optimal energy to the object to be dried. The control unit 100 uses these measurements to determine the type, size, and wetting of the load, as well as the optimal time to end the drying process.

[0241] Simultaneously, the control unit 100 can send notification signals or messages to the user before drying begins and at the end of the drying process. The notification signals can be sent visually via the display unit 119 or audibly via a speaker (not shown), as described above. The message can also be sent to the user's mobile phone in the form of a text message, for example, using the SMS protocol.

[0242] Figure 13 This is a flowchart illustrating a control method for a clothes dryer according to an embodiment of the present invention. Figure 16 This is a flowchart illustrating the process of controlling the rotational speed of the drum and the RF power for impedance matching during the drying process in a control method for a clothes dryer according to an embodiment of the present invention.

[0243] Reference Figures 1 to 3 and Figures 9 to 16 A method for controlling a clothes dryer according to an embodiment of the present invention is described.

[0244] The control method of the clothes dryer of the present invention may include a drying preparation step (S10), a load sensing step (S20), a drying step (S30), an agitation step (S40), and a cooling step (S60).

[0245] In the drying preparation step (S10), the object to be dried is contained in the drum 20, and the drying process can be set by the user's control input. When the object to be dried is placed in the drum 20, it is placed at the bottom of the drum 20 under the action of gravity, and the object to be dried contacts the notch 24 provided near the positive electrode 41 and the conductive drum body 21.

[0246] In the drying preparation step (S10), the user can input information about the material and quantity of the object to be dried through the input unit 118, and the input unit 118 can transmit this information to the control unit 100.

[0247] In this case, information about the heat of vaporization of each material of the object to be dried can be pre-stored in the control unit 100. Therefore, the control unit 100 can set the amount of energy applied to the object to be dried based on its material and size.

[0248] In the load sensing step (S20), the washing amount can be determined by sensing the load of the item to be dried.

[0249] The washing volume can be determined by measuring the current value of the drum motor 51 while the drum 20 is rotating and sensing the load acting on the drum motor 51.

[0250] For example, when the drum 20 is controlled to rotate at a speed that senses a predetermined washing load, a larger current must be applied to the drum motor 51 as the washing load increases. Therefore, the control unit 100 can control the current value applied to the drum motor 51. Thus, the control unit 100 can calculate the washing load based on the sensed current value of the drum electrode 51.

[0251] On the other hand, in the load sensing step (S20), the drum 20 can be stirred at a preset rotation speed w m Rotation. Stirring speed w m This will be described in detail in the stirring step (S40).

[0252] Simultaneously, the control unit 100 can pre-store the moisture content based on the material of the object to be dried. Therefore, the control unit 100 can predict the evaporation time of the moisture contained in the object to be dried based on information about the material and quantity of the object to be dried collected through the drying preparation step (S10) or the load sensing step (S20), and according to the amount of energy applied to the object to be dried. Furthermore, the control unit 100 can transmit the predicted moisture evaporation time to the display unit 119, and the display unit 119 can display the predicted time to the user.

[0253] In the drying step (S30), the control unit 100 can apply power to the positive electrode 41 and rotate the drum 20 to evaporate the moisture contained in the object to be dried by dielectric heating.

[0254] Specifically, the control unit 100 can apply power to the positive electrode 41 to generate an electric field related to the roller 20, which serves as the negative electrode. In this state, RF power can be applied to the roller 20 and the object to be dried. In this case, the current applied to the positive electrode 41 can be maintained at a predetermined frequency by the matching unit 42, and the source impedance of the high-frequency power supply and the impedance on the load side can be continuously matched by the matching unit 42.

[0255] The control unit 100 can control the matching unit 42 and the power supply unit 43 to measure appropriate power, drying, load size, and drying end time, and execute the drying process. In this case, the preferred operating frequency of the power supply 21 is in the range of 1MHz to 50MHz.

[0256] With this configuration, the positive electrode 41 maintains the electric field required by the roller 20 for drying the object to be dried, thereby generating a radio frequency (RF) capacitive coupling effect. In this case, a relatively low RF frequency is preferably used to minimize the parasitic capacitance generated in the roller 20, which serves as the negative electrode. For example, frequencies of 10 MHz or higher and 15 MHz or lower can be used for the positive electrode 41.

[0257] Therefore, it is possible to generate an alternating current through a semiconducting (wet) load of the object to be dried in a capacitor circuit, and to dielectrically heat the object to be dried by applying a single-frequency RF current between at least one positive electrode 41 and the roller 20.

[0258] In the drying step (S30), the control unit 100 can apply RF power to the positive electrode 41 within a preset drying time td. For example, the control unit 100 can apply RF power to the positive electrode 41 for a period of more than 80 seconds and less than 100 seconds, and preferably, apply RF power to the positive electrode 41 for a period of 90 seconds.

[0259] On the other hand, in conventional dielectric heating dryers, the drum stops rotating when power is applied to the positive electrode. This allows the matching device to perform impedance matching once at the start of drying and then continue heating, thus enabling it to effectively and rapidly heat the moisture contained in the object to be dried.

[0260] However, when the internal temperature of the object to be dried rises rapidly as described above, localized overheating can occur inside the object.

[0261] In particular, when the object to be dried is dyed synthetic fiber, there is a problem of color transfer due to localized overheating. In the case of synthetic fibers, color transfer may occur if the temperature exceeds 50 degrees Celsius.

[0262] To address this issue, conventional dryers rotate the drum for 5 seconds after 90 seconds of drying to mix the items being dried. However, since dielectric heating is performed again before the heat inside the items has been fully dissipated, a problem arises: the internal temperature of the items continues to rise as the drying cycle progresses.

[0263] Reference Figure 14 Considering the temperature changes of the object to be dried, we can see the internal temperature changes of the object when dried using a conventional dielectric heating method. RF power was applied for 90 seconds when the drum stopped, and then stopped for 5 seconds. This process of rotating the drum was repeated for 36 cycles. The results show that the internal temperature of the object to be dried rose to 145 degrees Celsius.

[0264] Furthermore, when heating occurs after sufficient internal heat has been released, the energy and time required for reheating with dielectric material are both significant, resulting in a decrease in drying efficiency.

[0265] Therefore, it is necessary to control the process to prevent localized overheating while maintaining the heat on the object to be dried.

[0266] To address this issue, in the drying step (S30) of this invention, the control unit 100 rotates the drum 20 while applying power to the positive electrode 41. In other words, in the drying step (S30), the control unit 100 rotates the drum 20 at a preset drying speed wd.

[0267] In this case, the rotational speed of the drum 20 may be slower than the rotational speed of the drum 20 in the load sensing step (S20) or the rotational speed of the drum 20 in the agitation step (S40) described below.

[0268] Specifically, the rotational speed range of the drum 20 in the drying step (S30) can be determined from two aspects.

[0269] First, the rotational speed of the drum 20, which will not cause localized overheating during the drying step (S30), is determined as follows.

[0270] To prevent color transfer to the object being dried, the temperature of the object should be kept below 50 degrees Celsius. Therefore, it is necessary to maintain a low temperature rise per heating time. The temperature rise per unit time is as follows.

[0271] [Formula 1]

[0272]

[0273] In this case, ΔT represents the temperature rise (°C), and Δt represents the heating time (seconds). Furthermore, Cp is the specific heat of the dielectric (J / kg·K), f is the frequency (Hz), and ρ is the density of the dielectric (kg / m³). 3 ), where ε0 is the dielectric constant under vacuum conditions.

[0274] Meanwhile, Pv is the power absorbed per unit volume of the dielectric, and it can be expressed by the following formula.

[0275] [Formula 2]

[0276] P v =2π·f·ε0·ε″E 2

[0277] In this case, ε" refers to the relative electrical loss coefficient, while E refers to the electron density.

[0278] Here, taking into account the travel distance caused by the rotation of the roller 20, combining the above formulas 1 and 2, we can obtain the following formula.

[0279] [Formula 3]

[0280]

[0281] When the ambient temperature is 20 degrees Celsius, the temperature change must be 30 degrees or less to keep the temperature of the object to be dried at 50 degrees Celsius or less. Therefore, in the drying step (S30), the minimum rotational speed of the drum 20 is determined by the following formula.

[0282] [Formula 4]

[0283]

[0284] In this case, θ (rad) represents the angle of the positive electrode 41 relative to the rotation axis of the roller 20, and α represents the rotational speed of the roller 20. Thus, in this invention, the rotational speed of the roller 20 is proportional to the angle occupied by the positive electrode 41 relative to the rotation axis of the roller 20.

[0285] For example, if a 4000W RF power at a frequency of 13.56MHz is applied to the positive electrode, and the arc-shaped positive electrode 41 surrounds the roller 20 at an angle (range) of 120 degrees (2π / 3), then the minimum rotational speed in the drying step (S30) of the present invention is 1.6 rpm. Furthermore, considering that the minimum rotational speed α of the roller 20 is proportional to θ (rad), the proportional relationship between the angle of the positive electrode 41 surrounding the roller 20 and the minimum rotational speed of the roller 20 is as follows.

[0286] [Formula 5]

[0287]

[0288] In other words, the minimum rotational speed of the drum 20 is 12 / 5π times the angle of the positive electrode 41 around the drum 20 with the rotation axis of the drum 20 as the origin.

[0289] Meanwhile, in the drying step (S30), the control unit 100 can rotate the drum 20 while keeping the rotational speed of the drum 20 below 7 rpm.

[0290] Specifically, in a dielectric-heated RF dryer, as the rotational speed of the drum 20 increases, the load also increases, making it difficult for the matching circuit 42 to match the source impedance and the load-side impedance. Therefore, when the rotational speed of the drum 20 exceeds 7 rpm, dielectric heating may not occur inside the object to be dried.

[0291] Therefore, in the drying step (S30), the control unit 100 can rotate the roller 20 at an angle of 12 / 5π times or greater than the angle of the positive electrode 41 around the roller 20, and the rotation speed is 7 rpm or less.

[0292] With this construction, the control method of the clothes dryer according to an embodiment of the present invention has the following effect: by keeping the temperature of the item to be dried below 50 degrees Celsius, and by removing the moisture in the item to be dried by dielectric heating of the inside of the item to be dried, color transfer is prevented.

[0293] Furthermore, in this method, the matching unit 42 needs approximately 7 seconds to match the impedance before supplying RF power again. Therefore, there is a problem that power may be wasted during this process, and the overall drying time is increased.

[0294] To address this issue, in the drying step (S30) of the present invention, the control unit 100 rotates the drum 20 while applying power to the positive electrode 41. In this case, the rotational speed of the drum 20 may be slower than the rotational speed of the drum 20 in the load sensing step (S20) or the rotational speed of the drum 20 in the agitation step (S40) described below.

[0295] Furthermore, in the drying step (S30) of the present invention, when the reflectivity of the electric field exceeds a predetermined ratio, the control unit 100 reduces the rotational speed of the drum, and when the reflectivity of the electric field is less than or equal to the predetermined ratio, the control unit can increase the power applied to the positive electrode.

[0296] Specifically, the drying step (S30) includes a drying entry step (S31), a first power increase step (S33), a second power increase step (S35), a third power increase step (S37), and a rotation holding step (S39).

[0297] In the drying entry step (S31), the control unit 100 can apply a preset start-up power Pi to the positive electrode 41 and rotate the drum 20 at a preset start-up speed Wi. In other words, when power is applied to the positive electrode 41 according to the control command of the control unit 100, the power supply unit 43 can apply power corresponding to the preset start-up power Pi to the positive electrode 41.

[0298] For example, in the drying entry step (S31), the control unit 100 can apply a power of 100W or more and 200W or less to the positive electrode 41 through the power supply unit 43, and make the roller 20 rotate at a speed of 5rpm or more and 10rpm or less.

[0299] After the drying process (S31), the control unit 100 can obtain the reflectivity through the matching device 42. In other words, the matching device 42 can measure the electric field reflected wave reflected from and returned by the object being dried, and the control unit 100 compares it with the electric field incident wave generated at the positive electrode 41 to obtain the reflectivity of the electric field (S32).

[0300] In this case, when the reflectivity of the electric field exceeds a predetermined ratio, the control unit 100 can reduce the rotational speed of the drum 20. For example, when the reflectivity of the electric field exceeds 5%, the rotational speed of the drum 20 can be reduced by 10% (S32a). In other words, the rotational speed W of the drum 20 can be 90% of the starting speed (W = 0.9 × Wi).

[0301] Then, the control unit 100 can repeatedly reduce the rotational speed of the roller 20 until the reflectivity of the electric field of the roller 20 is less than or equal to a predetermined ratio. If the rotational speed is reduced n times, the rotational speed W of the roller 20 can be (0.9). n×Wi(W=(0.9) n ×Wi).

[0302] Simultaneously, when the reflectivity of the electric field is less than or equal to a predetermined ratio, the control unit 100 may execute a first power increase step (S33). For example, when the reflectivity of the electric field is less than 5%, the first power increase step (S33) may be executed.

[0303] In the first power increase step (S33), the control unit 100 can increase the power P applied to the positive electrode 41. For example, when the reflectivity of the electric field is less than 5%, the control unit 100 can transmit RF power equivalent to 20% of the preset drying power Pd (P = 0.2 × Pd) to the positive electrode 41 through the power supply unit 43.

[0304] Simultaneously, the rotational speed W1 of the drum 20 in the first power increase step (S33) can maintain the rotational speed W of the drum 20 in the previous step. In other words, if the rotational speed of the drum 20 decreases after the drying enters the step (S31), the decreased rotational speed of the drum 20 (W1 = (0.9)) is maintained. n If the rotational speed of the drum 20 does not decrease after the drying process (S31), the starting speed (W1 = Wi) can be maintained.

[0305] When the reflectivity of the electric field is less than or equal to a predetermined ratio, a power equivalent to 20% of the preset drying power can be applied to the positive electrode.

[0306] After the first power increase step (S33), the control unit 100 can obtain the reflectivity through the matching device 42. In other words, the matching device 42 can measure the electric field reflected wave reflected and returned from the object to be dried, and the control unit 100 compares it with the electric field incident wave generated from the positive electrode 41 to obtain the reflectivity of the electric field (S34).

[0307] In this case, when the reflectivity of the electric field exceeds a predetermined ratio, the control unit 100 can reduce the rotational speed W of the roller 20. For example, when the reflectivity of the electric field exceeds 5%, the rotational speed of the roller 20 can be reduced by 10% (S34a). In other words, the rotational speed W of the roller 20 can be 90% of the starting speed (W = 0.9 × W1).

[0308] Then, the control unit 100 can repeatedly reduce the rotational speed of the roller 20 until the reflectivity of the electric field of the roller 20 is less than or equal to a predetermined ratio. If the rotational speed is reduced n times, the rotational speed W of the roller 20 can be (0.9). n ×W1(W=(0.9) n ×W1).

[0309] Simultaneously, when the reflectivity of the electric field is less than or equal to a predetermined ratio, the control unit 100 may execute a second power increase step (S35). For example, when the reflectivity of the electric field is less than 5%, the second power increase step (S35) may be executed.

[0310] In the second power increase step (S35), the control unit 100 can increase the power P applied to the positive electrode 41. In other words, when the power applied to the positive electrode 41 is equivalent to 20% of the drying power Pd, and the reflectivity of the electric field is less than or equal to a predetermined ratio, the power supply unit 43 can apply 50% of the power corresponding to the drying power Pd to the positive electrode 41 according to the control command of the control unit 100.

[0311] For example, when the reflectivity of the electric field is less than 5%, the control unit 100 can apply radio frequency power (P = 0.5 × Pd) equivalent to 50% of the preset drying power Pd to the positive electrode 41 through the power supply unit 43.

[0312] Simultaneously, in the second power increase step (S35), the rotational speed W2 of the roller 20 can be maintained at the rotational speed W of the roller 20 in the previous step. In other words, if the rotational speed of the roller 20 decreases, the decreased rotational speed (W2 = (0.9)) of the roller 20 is maintained. n If the rotational speed does not decrease after the drying process (S31), the starting rotational speed Wi (W2 = Wi) can be maintained.

[0313] After the second power increase step (S35), the control unit 100 can obtain the reflectivity through the matching device 42. In other words, the matching device 42 can measure the electric field reflected wave reflected and returned from the object to be dried, and the control unit 100 compares it with the electric field incident wave generated from the positive electrode 41 to obtain the reflectivity of the electric field (S36).

[0314] In this case, when the reflectivity of the electric field exceeds a predetermined ratio, the control unit 100 can reduce the rotational speed W of the roller 20. For example, when the reflectivity of the electric field exceeds 5%, the rotational speed of the roller 20 can be reduced by 10% (S36a). In other words, the rotational speed W of the roller 20 can be 90% of the starting speed (W = 0.9 × W2).

[0315] Then, the control unit 100 can repeatedly reduce the rotational speed of the roller 20 until the reflectivity of the electric field of the roller 20 is less than or equal to a predetermined ratio. If the rotational speed is reduced by a factor of n, the rotational speed W of the roller 20 can be (0.9). n ×W2(W=(0.9) n ×W2).

[0316] Simultaneously, when the reflectivity of the electric field is less than or equal to a predetermined ratio, the control unit 100 may execute a third power increase step (S37). For example, when the reflectivity of the electric field is less than 5%, the third power increase step (S37) may be executed.

[0317] In the third power increase step (S37), the control unit 100 can increase the power P applied to the positive electrode 41. In other words, when the power applied to the positive electrode 41 corresponds to 50% of the drying power (Pd), and the reflectivity of the electric field is less than or equal to a predetermined ratio, the power supply unit 43 can apply power corresponding to 100% of the drying power Pd according to the control command of the control unit 100.

[0318] For example, when the reflectivity of the electric field is below 5%, the control unit 100 can apply a preset drying power Pd to the positive electrode 41 through the power supply unit 43. For example, the drying power Pd can be 4000W.

[0319] Simultaneously, in the third power increase step (S37), the rotational speed W3 of the roller 20 can be maintained at the rotational speed W of the roller 20 in the previous step. In other words, if the rotational speed of the roller 20 decreases, the decreased rotational speed (W3 = (0.9)) of the roller 20 is maintained. n ×W2), and if there is no speed reduction after the drying entry step (S31), the starting speed Wi (W3 = Wi) can be maintained.

[0320] After the third power increase step (S37), the control unit 100 can obtain the reflectivity through the matching device 42. In other words, the matching device 42 can measure the electric field reflected wave reflected and returned from the object to be dried, and the control unit 100 compares it with the electric field incident wave generated from the positive electrode 41 to obtain the reflectivity of the electric field (S38).

[0321] In this case, when the reflectivity of the electric field exceeds a predetermined ratio, the control unit 100 can reduce the rotational speed W of the drum 20. For example, when the reflectivity of the electric field exceeds 5%, the rotational speed of the drum 20 can be reduced by 10% (S38a). In other words, the rotational speed W of the drum 20 can be 90% of the starting speed (W = 0.9 × W3).

[0322] Then, the control unit 100 can repeatedly reduce the rotational speed of the roller 20 until the electric field reflectivity of the roller 20 is less than or equal to a predetermined ratio. If the rotational speed is reduced by a factor of n, the rotational speed W of the roller 20 can be (0.9). n ×W3(W=(0.9) n ×W3).

[0323] On the other hand, when the reflectivity of the electric field is less than or equal to a predetermined ratio, the control unit 100 may perform a rotation holding step (S39). For example, when the reflectivity of the electric field is less than 5%, the rotation holding step (S39) may be performed.

[0324] In the rotation holding step (S39), the control unit 100 can apply drying power Pd to the positive electrode 41 and maintain the rotational speed of the drum 20 to dry the object to be dried. In other words, when the drying power Pd is applied to the positive electrode 41 and the reflectivity of the electric field reflected from the object to be dried is less than or equal to a predetermined ratio, the control unit 100 can maintain the rotational speed of the drum 20.

[0325] Specifically, in the rotation holding step S39, the control unit 100 can continuously maintain the drying power Pd applied to the positive electrode 41 in the third power increasing step (S37). Furthermore, in the rotation holding step (S39), the final rotational speed Wf of the roller 20 can be maintained at the rotational speed W of the roller 20 in the previous step. In other words, if the rotational speed of the roller 20 decreases in the previous step, the decreased rotational speed (Wf = (0.9)) of the roller 20 is maintained. n ×W3), and if the roller 20 does not decrease after the drying entry step (S31), the starting speed Wi (Wf = Wi) can be maintained.

[0326] With this construction, the control method of the clothes dryer according to an embodiment of the present invention has the following effects: removing moisture from the item to be dried by heating the interior of the item with a dielectric material; preventing local overheating of the item to be dried by rotating the drum 20; and preventing color transfer by keeping the temperature of the item to be dried below 50 degrees Celsius.

[0327] In particular, in a dielectric heating type dryer in which the positive electrode 41 is fixed and the drum 20 rotates, the control method of the clothing dryer according to an embodiment of the present invention can have the effect of heating the items to be dried contained in the drum while the drum rotates.

[0328] In this case, the drying process can be started immediately by controlling the rotational speed of the drum and the RF power to reduce the reflectivity of the electric field, without the need for separate impedance matching time, thus saving the time and energy required for impedance matching.

[0329] In addition, it also has the effect of preventing damage to equipment (such as matching devices) due to reflected waves.

[0330] Furthermore, in the drying step (S30), the object to be dried can come into contact with the lifter 25 at least once by the rotation of the roller 20. When the object to be dried is mixed by the lifter 25, the effect of preventing local overheating can be increased.

[0331] Meanwhile, during the drying step (S30), the control unit 100 can drive the circulating fan 33 to exhaust the humid air present in the drum 20 to the outside. At the same time, air from outside the drum 20 can be introduced into the drum 20.

[0332] With this configuration, water vapor can be evaporated from the object to be dried by airflow. In addition, the overheated positive electrode 41 and matching device 42 can be cooled by this airflow.

[0333] Meanwhile, as another embodiment, in the drying step (S30), the control unit 100 can measure the temperature of the object to be dried through the sensor unit 101, and when the temperature of the object to be dried is equal to or higher than the preset reference temperature, the control unit can control the rotation speed of the roller 20 to maintain the internal temperature of the object to be dried below 50 degrees.

[0334] Meanwhile, in the stirring step (S40), the control unit 100 can cut off the power applied to the positive electrode 41 and rotate the drum 20 to mix the objects to be dried.

[0335] Specifically, in the agitation step (S40), the control unit 100 cuts off the power applied in the drying step (S30) to stop the dielectric heating, and the drum 20 can operate at a preset agitation speed w m Rotate.

[0336] This design prevents overheating caused by prolonged use of the power supply unit 43, while also ensuring that the items to be dried are evenly mixed and heated.

[0337] In this case, the rotational speed of drum 20 in the agitation step (S40) is faster than that in the drying step (S30). In other words, the drying speed wd is less than the agitation speed w. m For example, the stirring speed w m It can be 30 rpm.

[0338] On the other hand, in conventional hot air supply dryers, the drum rotates continuously at 50 rpm to uniformly supply hot air to the objects to be dried during the drying process.

[0339] In this configuration, the object to be dried rotates under centrifugal force and moves upward inside the drum, then descends under gravity. While increasing the contact area with hot air as the object falls improves drying performance, a problem arises: the object shrinks due to mechanical forces.

[0340] In contrast, in a dielectric heating dryer, the interior of the object to be dried is heated. It is necessary to mix and heat the object to be dried evenly, but it is not necessary to generate a downward motion that causes the object to be dried to shrink.

[0341] In other words, in a dielectric heating dryer, it is necessary to reduce the shrinkage rate of the object to be dried by preventing it from falling during the process of agitating the object to be dried.

[0342] To address this issue, in the agitation step (S40) according to an embodiment of the present invention, the control unit 100 controls the drum motor 51 to rotate the drum 20 at a speed of less than 50 rpm. In other words, in the agitation step (S40) according to an embodiment of the present invention, the agitation speed w m Less than 50 rpm.

[0343] Specifically, in the agitation step (S40), the agitation speed w is used to make the object to be dried slide along the inner circumferential surface of the drum 20 without falling. m It can be obtained in the following ways.

[0344] In the agitation step (S40), when the drum motor 51 is driven by the command of the control unit 100, the drum 20 rotates around the rotation axis, and the object to be dried can move along the inner circumferential surface of the drum 20.

[0345] Specifically, the rotation axis of the roller 20 can be arranged parallel to the ground or at a predetermined angle to the ground. In this case, when the object to be dried is placed into the roller 20, it is gathered in the roller 20 near the ground under the influence of gravity. Furthermore, at least a portion of the object to be dried is in contact with the inner circumferential surface of the roller 20. Additionally, the object to be dried is compressed due to its weight on the inner circumferential surface of the roller 20.

[0346] When the roller 20 starts to rotate, the inner circumferential surface of the roller 20 that is in contact with the object to be dried also begins to rotate. In this case, the object to be dried will also rotate around the rotation axis of the roller 20 together with the inner circumferential surface of the roller 20 due to the pressure of the object to be dried on the inner circumferential surface of the roller 20 caused by gravity or inertia.

[0347] In this case, the maximum speed of the items to be dried can be the speed of the roller 20. However, due to gravity, air resistance, and other factors, the speed of the items to be dried may be reduced.

[0348] As a result, when the radius of the drum 20 is r, it contains a stirring speed w m The maximum speed v of the items to be dried in the rotating drum 20 is equal to the radius r of the drum 20 and the agitation speed w. mThe product (v = r × w) m ).

[0349] Therefore, when the mass of the object to be dried is m, the maximum kinetic energy (Ek) of the object to be dried in the stirring step (S40) is as follows.

[0350]

[0351] On the other hand, when the object to be dried moves upward along the inner circumferential surface of the drum in the direction of gravity due to the rotation of the drum 20, the height difference h from the point near the ground to the position of the object to be dried within the drum 20 may generate potential energy Ep. Therefore, when the object to be dried moves through the drum, the potential energy Ep is as follows.

[0352] Ep = mgh

[0353] In this case, in order for the object to be dried to move downwards, the potential energy Ep must be greater than the kinetic energy Ek (Ep>Ek).

[0354]

[0355] Furthermore, even if the potential energy Ep is greater than the kinetic energy Ek, if the point is too high inside the drum 20, it may still fall due to gravity. Therefore, at the appropriate height h, the potential energy Ep must be greater than the kinetic energy Ek. In other words, taking the cross-section (circle) of the drum 20 as a reference, even if a part of the item to be dried moves to the upper semicircular region of the drum 20, it will still fall due to gravity. Therefore, the entire item to be dried must have a potential energy Ep greater than the kinetic energy Ek in the lower semicircular region of the drum 20.

[0356] In this case, considering that in this embodiment, the positive electrode 41 is formed within a range of 120 degrees relative to the rotation axis of the drum 20, and the object to be dried is heated within the range of the positive electrode 41, it can be seen that the object to be dried is distributed within a range of up to 120 degrees relative to the rotation axis of the drum 20. In other words, it can be seen that it is symmetrically distributed within a range of 60 degrees based on the vertical line. Therefore, in order to ensure that all the objects to be dried are located in the lower semi-circular region of the drum 20, the objects to be dried must only move within a range of 30 degrees based on the rotation axis of the drum 20.

[0357] In this case, the height h is summarized by the radius r of the roller 20 as follows.

[0358]

[0359] Therefore, if set according to the above formula, the stirring speed w mIt can have the following range.

[0360]

[0361] In other words, the square of the agitation speed can be set inversely proportional to the radius of the drum.

[0362] The value obtained by multiplying the radius of the drum by the square of the agitation speed (rad / s) can be 0.27 times the magnitude of gravitational acceleration or less.

[0363] For example, if the radius r of drum 20 is 30cm, the stirring speed w m It can be around 28.4 rpm.

[0364] However, the above range implies that the speed of the object to be dried will not decrease due to gravity, air resistance, etc. When the moving speed of the object to be dried decreases due to gravity, air resistance, etc., even at a stirring speed of w... m This increases the rate of change, and the falling motion of the object to be dried will not occur. Accordingly, this difference in rotational speed is included within the spirit and scope of the invention.

[0365] Therefore, the stirring speed w is set when the falling motion of the object to be dried is essentially negligible. m The stirring speed can be below 30 rpm.

[0366] With this configuration, when the drum 20 is at an agitation speed w m As the drum rotates, the items to be dried can slide along the inner circumferential surface of the drum.

[0367] on the other hand, Figure 17 This is a graph showing the difference in shrinkage rate over time when a control method for a clothes dryer according to an embodiment of the present invention is applied.

[0368] The graph shows the shrinkage rate of the cotton fabric when the roller rotates at 30 rpm or less for the entire period (0 minutes), at 50 rpm for the first 20 minutes and then at 30 rpm or less, at 50 rpm for the first 40 minutes and then at 30 rpm or less, and at 50 rpm for the entire period (80 minutes).

[0369] In other words, as the time of the falling motion caused by the drum rotating at 50 rpm increases, the shrinkage rate also increases proportionally. Therefore, if the drum 20 is driven at 30 rpm or lower in all agitation steps (S40), the shrinkage rate of the object to be dried (typically about 4% to 5%) can be reduced to 1.5%.

[0370] Therefore, according to the present invention, it is possible to reduce the shrinkage rate of the object to be dried due to mechanical force by preventing the object from falling.

[0371] Meanwhile, during the agitation step (S40), the control unit 100 can drive the circulating fan 33 to discharge the humid air present in the drum 20 to the outside. At the same time, air from outside the drum 20 can be introduced into the drum 20.

[0372] With this configuration, water vapor can be evaporated from the object to be dried by airflow. In addition, the overheated positive electrode 41 and matching device 42 can be cooled by this airflow.

[0373] In the agitation step (S40), the control unit 100 may stop applying RF power within a preset agitation time tm and only rotate the drum 20. For example, the control unit 100 may stop applying RF power and only rotate the drum 20 for a period of 3 seconds or more and 7 seconds or less, preferably stop applying RF power for a period of 5 seconds and then only rotate the drum 20.

[0374] Simultaneously, the drying step (S30) and agitation step (S40) are repeated until a preset degree of dryness is reached (S50). In this case, the degree of dryness can be determined based on the load of the object to be dried, depending on whether the load of the object to be dried is reduced to a preset level in the drying preparation step (S10), and the degree of dryness can be determined by temperature changes or humidity changes inside the drum. Furthermore, the degree of dryness can also be determined by calculating the drying time by considering the applied RF power and the heat capacity of each material of the object to be dried. For example, the drying step (S30) and agitation step (S40) can be repeated 36 times within 1 hour.

[0375] Reference Figure 15 Considering the temperature change of the item to be dried to which the control method of the clothes dryer according to the embodiment of the present invention applies, the temperature difference from the first cycle to the last 36th cycle is very small, and it can be seen that the temperature is maintained below 50 degrees.

[0376] Therefore, according to the present invention, the control unit 100 has the effect of maintaining the internal temperature of the object to be dried below 50 degrees Celsius to prevent color transfer from occurring in the object to be dried.

[0377] Simultaneously, in the cooling step (S60), when the object to be dried reaches a preset dryness level, the control unit 100 cools the object. Cooling refers to the process of drying the object by using the circulating fan 33 without operating the electric field generator 40. In other words, when the object to be dried reaches the preset dryness level, the control unit 100 drives the circulating fan 33 to perform a predetermined time and rotate the drum 20. As a result, the object to be dried, contained in the drum 20, rotates along the drum 20 and is dried according to the airflow generated by the circulating fan 33.

[0378] After the cooling step (S60), the overall drying process of the clothes dryer according to this embodiment of the invention ends.

[0379] Although the present invention has been described in detail through specific embodiments, it is intended to describe the invention in detail, but the invention is not limited thereto. Obviously, those skilled in the art can modify or improve the invention within the scope of its technical spirit.

[0380] All simple modifications or variations of this invention are within the scope of this invention, and the specific scope of protection of this invention will be interpreted by the appended claims.

Claims

1. A clothes dryer, comprising: chassis; A roller, rotatably mounted in the housing, is adapted to hold items to be dried; An electric field generator, spaced apart from the drum, is configured to generate an electric field inside the drum when powered. as well as An exhaust pipe that discharges air from inside the drum. The electric field generator includes: A positive electrode, spaced apart from the drum, is fixed to the housing and configured to apply an electric field to the object to be dried contained in the drum; A power supply unit that supplies power to the positive electrode; and A matching circuit, housed within the housing, is configured to match the power supply impedance with the load-side impedance. The roller is configured such that when the reflectivity of the electric field exceeds a predetermined ratio, the rotational speed of the roller decreases, and The electric field generator is configured to increase the power applied to the positive electrode when the reflectivity of the electric field is less than or equal to the predetermined ratio.

2. The clothes dryer according to claim 1, wherein, The roller is configured such that when the reflectivity of the electric field exceeds the predetermined ratio, the rotational speed of the roller decreases by 10%.

3. The clothes dryer according to claim 1, wherein, The electric field generator is configured to apply power to the positive electrode corresponding to a preset start-up power when power is applied to the positive electrode. Furthermore, the electric field generator is configured to apply power corresponding to 20% of a preset drying power when the reflectivity of the electric field is less than or equal to the predetermined ratio.

4. The clothes dryer according to claim 3, wherein, The electric field generator is configured to apply power corresponding to 50% of the drying power to the positive electrode when the power applied to the positive electrode corresponds to 20% of the drying power and the reflectivity of the electric field is less than or equal to the predetermined ratio.

5. The clothes dryer according to claim 3, wherein, The electric field generator is configured to apply power corresponding to 100% of the drying power to the positive electrode when the power applied to the positive electrode corresponds to 50% of the drying power and the reflectivity of the electric field is less than or equal to the predetermined ratio.

6. The clothes dryer according to claim 1, wherein, The drum is configured to maintain the rotational speed when a preset drying power is applied to the positive electrode and the reflectivity of the electric field reflected from the object to be dried is less than or equal to the predetermined ratio.

7. The clothes dryer according to claim 1, wherein, The roller is configured to rotate when power is applied to the positive electrode.

8. A control method for a clothes dryer, the clothes dryer comprising a drum for accommodating items to be dried and a positive electrode spaced apart from the drum, the positive electrode being used to generate an electric field within the drum, the control method comprising: The drying step involves applying power to the fixed positive electrode and rotating the drum. as well as The agitation step involves cutting off the power applied to the positive electrode and rotating the drum. In the drying step, when the reflectivity of the electric field exceeds a predetermined ratio, the rotational speed of the drum is reduced, and when the reflectivity of the electric field is less than or equal to the predetermined ratio, the power applied to the positive electrode is increased.

9. The control method for a clothes dryer according to claim 8, wherein, The drying step includes: Drying entry step: Apply a preset starting power to the positive electrode and rotate the drum at a preset starting speed; and Rotation holding step: Apply a preset drying power to the positive electrode and maintain the rotational speed of the drum.

10. The control method for a clothes dryer according to claim 9, wherein, In the drying step, after the drying entry step, when the reflectivity of the electric field exceeds the predetermined ratio, the rotational speed of the drum is reduced.

11. The control method for a clothes dryer according to claim 9, wherein, The drying step further includes a first power increase step, namely, after the drying entry step, when the reflectivity of the electric field is less than or equal to the predetermined ratio, the power applied to the positive electrode is increased to 20% of the drying power.

12. The control method for a clothes dryer according to claim 11, wherein, In the drying step, after the first power increase step, when the reflectivity of the electric field exceeds the predetermined ratio, the rotational speed of the drum is reduced.

13. The control method for a clothes dryer according to claim 11, wherein, The drying step further includes a second power increase step, which is that after the first power increase step, when the reflectivity of the electric field is less than or equal to the predetermined ratio, the power applied to the positive electrode is increased to 50% of the drying power.

14. The control method for a clothes dryer according to claim 13, wherein, In the drying step, after the second power increase step, when the reflectivity of the electric field exceeds the predetermined ratio, the rotational speed of the drum is reduced.

15. The control method for a clothes dryer according to claim 13, wherein, The drying step further includes a third power increase step, namely, after the second power increase step, when the reflectivity of the electric field is less than or equal to the predetermined ratio, the power applied to the positive electrode is increased to the drying power.

16. The control method for a clothes dryer according to claim 15, wherein, In the drying step, after the third power increase step, when the reflectivity of the electric field exceeds the predetermined ratio, the rotational speed of the drum is reduced.

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