Patent Publication Number: US-8966785-B2

Title: Method for controlling a laundry treatment apparatus according to target relative humidity

Description:
This application is a National Stage Entry of International Application No. PCT/KR2010/008888, filed Dec. 13, 2010, and claims the benefit of Korean Application No. 10-2009-0124666, filed on Dec. 15, 2009, each of which is hereby incorporated by reference for all purposes as if fully set forth herein. 
     TECHNICAL FIELD 
     The present invention relates to a control method of a laundry treatment apparatus. 
     BACKGROUND ART 
     Recently, various types of laundry treatment apparatuses have been used together with washing machines used to wash clothes, cloth items, beddings and the like. For example, drum type dryers used to dry washed laundry items, a cabinet type dryers used to dry laundry items hung therein and refreshers used to refresh laundry items supplied hot air. 
     However, such a cabinet type laundry treatment apparatus has several disadvantages. 
     DISCLOSURE 
     Technical Problem 
     To solve the problems, an object of the present invention is to provide a control method which is able to uniformly maintain the amount of moisture contained in each of laundry items, regardless of the amount of laundry items, when drying for the laundry items is completed. 
     Technical Solution 
     To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a The control method of a laundry treatment apparatus includes a humidity measuring step of measuring a relative humidity of an accommodating space accommodating laundry, a target humidity setting step of setting a target relative humidity based on the relative humidity measured in the humidity measuring step, to dry the laundry, and a heated air supplying step of supplying heated air to the accommodating space based on the target relative humidity. 
     In another aspect of the present invention, a control method of a laundry treatment includes a target relative humidity setting step of setting a target relative humidity based on a selected course, to dry laundry; a target maximum humidity and a target minimum humidity setting step of setting a target maximum humidity and a target minimum humidity according to the selected course; and a heated air supplying step of supplying heated air based on at least one of the target relative humidity, the target maximum humidity and the target minimum humidity. 
     Advantageous Effects 
     The present invention has following advantageous effects. The control method including the above steps may detect the relative humidity in the initial stage of the drying, when setting the target relative humidity used to determine the completion of drying, and it may set the target relative humidity based on the measured relative humidity. As a result, it is possible to remove deviation of the amount of water remaining in the laundry after completing the drying, regardless of the laundry amount. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       The accompanying drawings, which are included to provide further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiments of the disclosure and together with the description serve to explain the principle of the disclosure. 
       In the drawings: 
         FIG. 1  is a front view illustrating a laundry treatment apparatus according to an exemplary embodiment of the present invention; 
         FIG. 2  is a front view illustrating a laundry treatment apparatus according to another embodiment of the present invention; 
         FIG. 3  is a perspective view illustrating a moving hanger of  FIG. 2 ; 
         FIG. 4  is an exploded perspective view of  FIG. 3 ; 
         FIG. 5  is a diagram schematically illustrating an inner configuration of a mechanism chamber; 
         FIG. 6  is a flow chart illustrating a control method according to an exemplary embodiment of the present invention; 
         FIG. 7  is a flow chart illustrating a target humidity determining step of  FIG. 6  according to another embodiment; and 
         FIG. 8  is a flow chart specifically illustrating a heated air supplying step according to the embodiment of  FIG. 7 . 
     
    
    
     BEST MODE 
     Reference will now be made in detail to the specific embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     As follows, a laundry treatment apparatus according to an exemplary embodiment of the present invention will be described in reference to the accompanying drawings. 
       FIG. 1  is a front view illustrating that a door  14  provided in the laundry treatment apparatus according to the exemplary embodiment of the present invention is open. 
     This specification embodies a refresher configured to supply heated air to laundry to refresh, as laundry treatment apparatus, and the present invention is not limited thereto. A subject matter of the present invention may be applicable to other types of laundry treatment apparatuses including a heat pump, which will be described later. Here, the terminology ‘refresh’ means a process configured to supply air, heated air, water, mist and steam to laundry to performing wrinkles removal, deodorizing, sanitizing, static electricity prevention or warming. ‘laundry’ mentioned in the present specification includes not only clothes and apparel but also wearable items including shoes, socks, gloves, hats and mufflers people can wear, and usable laundry items including dolls, towels and beddings people can use. That is, the laundry may include all kinds of laundry items of which washing may be performed. 
     In reference to  FIG. 1 , a laundry treatment apparatus  100  according to the embodiment of the present invention includes a cabinet  10  having an accommodating space  12  formed therein to accommodate laundry, an air supply device ( 22 , see  FIG. 5 ) configured to supply air or heated air to the accommodating space  12 , a moisture generating device ( 30 , see  FIG. 2 ) configured to spray water, moist or steam to the accommodating space  12  selectively, and a control part (not shown) configured to control the air supply device  22  and the moisture generating device  30 . 
     A variety of components, which will be described later, are provided in the cabinet  10  and the accommodating space  12  to accommodate laundry therein is provided in the cabinet  10 . The accommodating space  12  may be in communication with an outside by a door  14  selectively and a variety of supporters  16  configured to hang the laundry thereon are provided in the accommodating space  12 . The supporters  16  may be provided to keep the laundry motionlessly still or fixed. Such the supporter may be configured to apply a predetermined movement to the laundry, when supplying air, heated air, water, mist or steam to the laundry, which will be described later. As follows, this configuration will be described in reference to  FIGS. 2 and 3 . 
       FIG. 2  is a front view illustrating a laundry treatment apparatus according to another embodiment of the present invention. Compared with the embodiment described above in reference to  FIG. 1 , the laundry treatment apparatus according to this embodiment includes a moving hanger configured to apply a predetermined movement to laundry, with laundry hung thereon. This difference will be described. 
     In reference to  FIG. 2 , the laundry is hung on a moving hanger  50  provided in the accommodating space  12 . The moving hanger  50  may apply a predetermined movement to the laundry. When supplying air, heated air, water, mist or steam to the laundry, the predetermined movement is applied to the laundry and then a laundry refreshing effect may be improved. 
       FIG. 3  is a perspective view illustrating a configuration of the moving hanger  50  and  FIG. 4  is an exploded perspective view illustrating the moving hanger  50 . 
     In reference to  FIGS. 3 and 4 , the moving hanger  50  includes a hanger bar  250  configured to support laundry hung on a hanger  200  and a supporting part  280  configured to support both ends of the hanger bar  250 . A plurality of hanger recesses  251  may be provided in the banger bar  250  to fix the location of the hanger  200  hung on the hanger bar  250 . The supporting part  280  is connected to a moving hanger frame  213  and the moving hanger frame  213  is provided beyond a ceiling of the cabinet  10 , not to be seen outside. Both ends of the hanger bar  250  include supporting part ribs  254 , respectively, and the supporting rib  254  is covering the end of the supporting part  280 . 
     As a result, the clothes received in the laundry treatment apparatus according to the present invention are hung on at least one hanger. Because of that, not only an improved refreshing effect but also improved drying efficiency for the clothes may be expected, compared with the conventional laundry treatment apparatus. 
     In the meanwhile, the moving hanger  50  includes a motor  230 , a power converting part  260  configured to convert a rotational force provided by the motor  230  into a horizontally linear motion of the hanger bar  250 , and a power transmitting part  240  configured to transmit the power generated from the motor  230  to the power transmitting part  260 . 
     The power transmitting part  240  includes a driving pulley  241  provided in the motor  230 , a driven pulley  242  connected to the driving pulley  241  by a belt  243 , and a shaft  244  coupled to a center of the driving pulley  242 . The shaft  244  may be rotatably provided in a bearing housing  270  provided in the moving hanger frame  213 . 
     The hanger bar  250  may further include a slot  252  which lies at right angles to its longitudinal direction. Specifically, a slot housing  253  is provided on the hanger bar  250  and the slot  252  is located approximately in a center of the slot housing  252 . The power converting part  260  may include a slot inserting portion  263  inserted in the slot  252 , a shaft connecting portion  261  connected to the shaft  244  and a rotation arm  262  connecting the slot inserting portion  263  and the shaft connecting portion  261  with each other. The power converting part  260  is covered by a cover  214  not to be seen outside and the cover  214  is provided between the moving hanger frame  213  and the slot housing  253 . 
     Under this configuration, when the motor  230  is rotated, the driving pulley  242  is rotated and the shaft  244  coupled to the driving pulley  242  is rotated. At this time, the slot inserting portion  263  will perform a circular motion, with a predetermined diameter. 
     Here, the slot  252  provided in the hanger bar  250  may be orthogonal to the longitudinal direction of the hanger bar  250 . By extension, the length of the slot  252  is larger than a rotational locus of the slot connecting portion  263 . Because of that, the slot  252  may perform a linear motion along a horizontal direction even when the slot inserting portion  263  performs a circular motion. 
     In the meanwhile, a mechanism chamber  20  configured to accommodate the air supplying device  22  and the moisture generating device  30  may be provided in the cabinet  10 . The mechanism chamber  20  may be located below the accommodating space  12  and it includes the air supplying device  22  and the moisture generating device  30  received therein. The reason why the mechanism chamber  20  is located below the accommodating space  12  is that the heated air or steam supplied to the accommodating space  12  has a property of ascending and that the mechanism chamber  20  is located below the accommodating space  12  to supply the heated air or steam upwardly. 
       FIG. 5  is a perspective view schematically illustrating an inner configuration of the mechanism chamber  20 . To illustrate the inner configuration of the mechanism chamber  20 , only a frame  11  of the cabinet  10  is shown in  FIG. 5  for convenience sake. In addition, only main components including the air supplying device  22  and the moisture generating device  30  are illustrated in  FIG. 5  for convenience sake and a drainage line connecting those components with each other is not illustrated. In reference to  FIG. 5 , the air supplying device  22  configured to supply air or heated air to the accommodating space  12  may be located within the mechanism chamber  20 . 
     A heat pump  22  embodied as the air supplying device according to the present invention may include an evaporator  24 , a compressor  26 , a condenser  28  and an expansion valve (not shown) which allow refrigerant to flow there through. Because of that, air is dehumidified and heated. 
     In other words, latent heat of ambient air is absorbed, while refrigerant is evaporated in the evaporator  24 . After that, air is cooled and moisture contained in the air is condensed and eliminated. When refrigerant is condensed in the condenser  28  after passing the compressor  26 , latent heat is exhausted toward ambient air. After that, the ambient air may be heated. As a result, the evaporator and the condenser  28  are functioned as heat exchanger. The air sucked into the mechanism chamber  20  may be dehumidified and heated while passing the evaporator  24  and the condenser  28 , to be supplied to the accommodating space  12 . 
     The air heated by the heat pump  22  has a relatively lower temperature than the air heated by a conventional electric heater. However, the air heated by the heat pump  22  may be dehumidified without using any auxiliary dehumidifying device. As a result, the air re-supplied to the accommodating space  12  by the heat pump  22  may be corresponding to ‘relatively low dry air’ (here, the term of ‘low temperature’ means not an absolutely low temperature but a relatively lower temperature than the temperature of conventional heated air). The laundry treatment apparatus according to the embodiment of the present invention may supply low temperature dry air to the laundry. Because of that, the laundry treatment apparatus according to the embodiment of the present invention may prevent deformity or damage which might be generated by the high temperature of heated air used in performing refreshing or drying for the laundry. That is, the air supplied by the heat pump  22  in the laundry treatment apparatus according to the embodiment of the present invention may have the lower temperature than the hot air supplied in the conventional laundry treatment apparatus but it may be dehumidified without any auxiliary dehumidifying device, to dry and refresh the laundry efficiently and smoothly. 
     Specifically, an air inlet ( 21 A, see  FIG. 5 ) is formed in a front portion of a top of the mechanism chamber  20  suck air of the accommodating space  12  into the mechanism chamber  20 . An air path of the air may be formed by an inlet duct  29  configured to connect the air inlet  21 A, the evaporator  24 , the condenser  28  and the fan  32  with each other. The air drawn into the mechanism chamber  20  via the air inlet  21 A by the inlet duct  29  may be dehumidified and heated while passing the heat pump  22 . The dehumidified and heated air may be re-supplied to the accommodating space  12  via an outlet duct  33  and an air outlet  21 B by a fan  32 . 
     Here, although not shown in the drawings, a filter may be provided in the air inlet  21 A. The filter provided in the air inlet  21 A may filter various foreign substances contained in the air drawn into the mechanism chamber  20  from the accommodating space  12  and only fresh air can be re-supplied to the accommodating space  12 . 
     Furthermore, the moisture generating device  30  may be provided in the mechanism chamber  20  to supply water, mist or steam (hereinafter, referenced to as ‘steam’) to the accommodating space  12  selectively. 
     The moisture generating device  30  includes a heater (not shown) configured to heat water and the water is heated to generate steam. The moisture generating device  30  supplies the generated steam to the accommodating space  12 . An external water tap may be used as water supply source supplying water to the moisture generating device  30  or a water supplying tank (not shown) may be provided in a predetermined portion of the mechanism chamber  20  as water supply source. 
     The water supplying tank may be provided in a door module  60  detachably installed in a predetermined portion of the mechanism chamber  20 . Because of that, a user may separate the water supplying tank from the mechanism chamber  20  for water refill and he or she may re-install the tank. 
     Also, the steam generated in the moisture generating device  30  is supplied to the accommodating space  12  via a steam hose  36  and a steam nozzle ( 40 , see  FIGS. 1 and 2 ). In this case, it is more preferable, as the shorter the steam hose  36  is, to prevent the temperature of the steam from being lowered or condensed while the steam moving through the steam hose  36 . When the mechanism chamber  20  is located below the accommodating space  12 , the steam nozzle  40  may supply steam via a top of the mechanism chamber  20  which is a bottom of the accommodating space  12 . 
     A circulating fan (not shown) may be provided in a rear portion of the mechanism chamber  20  and the circulating fan supplies external air to the mechanism chamber  20 . Because of that, the internal air of the mechanism chamber  20  may be prevented from increasing too much when the heat pump  22  and the moisture generating device  30  are put into operation. 
     As follows, a control method of the laundry treating apparatus having the above configuration will be described. The control method which will be described is corresponding to a step of drying laundry by supplying air or heated air to the laundry. 
     Such a drying step may be set as an auxiliary course, for example, drying course or included in the other courses. When drying the laundry, a humidity sensor is utilized to determine whether laundry drying is completed. That is, the humidity of air having passed the laundry is measured by the humidity sensor and it is determined whether the laundry drying is complete. 
     However, it is found according to experiments performed by the present inventor that the amount of relative humidity is variable according to the amount of laundry accommodated in the accommodating space, even if the amount of water contained in total laundry (hereinafter, ‘contained-water amount’) is constant. In other words, as the laundry amount is increasing, the relative humidity is getting heightened, even with the constant contained-water amount. As the laundry amount is decreasing, the relative humidity is getting lowered. As the laundry amount is increasing, a contact area between the laundry and air may be broad. Because of that, the water contained in the laundry is likely to disperse into air. As a result, when determining whether the laundry drying is complete based on the relative humidity of air, a target relative humidity is uniformly set according to a selected course and then laundry drying is performed. In this case, there may be severe deviation in the actually remaining amount of water contained in each of the laundry even after the target relative humidity is reached. Because of that, it is required to remove deviation of the amount of water remaining after the drying is completed, regardless of the laundry amount. 
       FIG. 6  is a flow chart illustrating a control method according to an embodiment of the present invention. 
     In reference to  FIG. 6 , a control method according to this embodiment includes a humidity measuring step (S 610 ) of measuring a relative humidity of the accommodating space accommodating laundry therein, a target humidity determining step (S 630 ) of determining a target relative humidity configured to dry the laundry based on the relative humidity measured in the humidity measuring step, and a heated air supplying step (S 650 ) of supplying heated air to the accommodating space based on the target relative humidity. First of all, a user may select one of at least one course including the drying step, which is provided in the laundry treatment apparatus. 
     Hence, the control part of the laundry treatment apparatus measures a relative humidity of the accommodating space accommodating laundry therein (S 610 ). This step is configured to measure the relative humidity of the accommodating space accommodating the laundry, before supplying heated air to the laundry or in an initial stage of the heated air supplying, and to determine a target relative humidity based on the measured relative humidity. As described above, if the target relative humidity is set uniformly according to the courses, there might be severe deviation of the amount of water contained in the laundry after completing the drying according to the laundry amount. Because of that, the control method according to this embodiment measures the relative humidity of the space accommodating the laundry therein in the initial stage of the drying step, not setting the target relative humidity according to the courses uniformly. After that, the control method sets the target relative humidity based on the measured relative humidity. In setting the target relative humidity, the control method according to this embodiment uses the relative humidity measured in the initial stage of the drying. As a result, even after completing the drying, deviation of the amount of contained water may be reduced even after completing the drying. 
     When measuring the relative humidity, the relative humidity is measured by using the humidity sensor provided in the laundry treatment apparatus. The humidity sensor may detect the humidity of air having passed the laundry and it may be provided adjacent to an air inlet  21 A. When measuring the relative humidity by using the humidity sensor and simultaneously supplying the heated air to the laundry, values measured by the humidity sensor are not precise. 
     Simultaneously supplying the heated air, the humidity sensor is put into operation to measure the relative humidity. Because of that, the humidity sensor is not stabilized yet. The control method according to this embodiment includes a humidity stabilizing step of stabilizing the humidity sensor for a predetermined time period after supplying the heated air to the laundry. For example, the stabilizing step may include a step of supplying heated air for 3 to 5 minutes. After that, the control part controls the humidity sensor to measure the relative humidity. When measuring the relative sensor, the control part measures the relative humidity by using the humidity sensor for a predetermined time period and it determines an average of the measured values as measured humidity. 
     After measuring the relative humidity, the control part sets the target relative humidity (S 630 ). The control part determines the target relative humidity based on the measured relative humidity and it sets the target relative humidity according to the selected course. 
     Specifically, the control part determines a value having a predetermined difference (A) out of the measured relative humidity values. For example, when the relative humidity measured in the initial stage of the drying is 60%, a target relative humidity is set as value remaining after subtracting ‘A’ from 60%. 
     In the meanwhile, the predetermined value (A) may be adjusted properly based on the selected course. For example, in case of requiring strong drying, ‘A’ may be set to be a relatively large value. In an ironing course, the user is expected to iron the laundry after the drying and then ‘A’ may be set to be a relatively small value. In a standard drying course, ‘A’ may be set to be larger than in the ironing course. 
     After the setting the target relative humidity, the control part controls the air supply device  22  to supply heated air to the accommodating space. The control part controls the humidity sensor to detect the relative humidity of air continuously or periodically, simultaneously supplying the heated air. The control part determines that the drying is completed when the relative humidity measured by the humidity sensor reaches a target relative humidity and it controls the operation of the air supply device to finish, such that the drying step is completed. 
     However, when the heated air is supplied according to the target relative humidity set based on the relative humidity measured in the initial stage of the drying, drying for the laundry happens to be performed too much (over-drying) or drying is finished in a state of the laundry being dried not sufficiently. For example, when the relative humidity measured in the initial stage of the drying is too high, the target relative humidity may be set relatively high and the drying may be finished with the laundry dried not sufficiently. In contrast, when the relative humidity measured in the initial stage is relatively low, the target relative humidity may be set too low and the over-drying may be performed for the laundry. Such the over-drying and insufficient-drying may be generated even if the target relative humidity is variable by several elements, for example, a peripheral temperature/internal temperature of the laundry treatment apparatus, a relative humidity of air and the amount/quality of laundry. 
     As a result, a control method configured to prevent the over-drying and insufficient-drying will be described according to an embodiment. 
       FIGS. 7 and 8  are flow charts illustrating a control method according to an embodiment to prevent the over-drying and insufficient-drying. 
     In reference to  FIG. 7 , a target humidity setting step ( 630 ) of the control method according to this embodiment further includes a target relative humidity determining step (S 631 ) and a target maximum humidity and/or a target minimum humidity determining step (S 633 ). The target maximum humidity is configured to prevent the insufficient drying and the target minimum humidity is to prevent the over-drying. 
     The target maximum humidity and the target minimum humidity may be set properly according to the selected course, regardless of the relative humidity measured in the initial stage of the drying. For example, the target maximum humidity may be set to be getting lower in the order of the ironing course, the standard drying course and the strong drying course. The target minimum humidity may be set to be getting lower in the same order of the standard drying course and the strong drying course. Here, the target maximum humidity may be set to be the target minimum humidity or lower in a single course. 
       FIG. 8  is a flow chart illustrating a heated air supplying step of supplying heated air to the accommodating space according to this embodiment. 
     In reference to  FIG. 8 , the control part starts the heated air supplying (S 651 ) and it compares the measured relative humidity with the target humidity continuously or periodically (S 653 ). In this case, when the measured humidity is the target relative humidity or lower, the control part re-compares the measured humidity with the target maximum humidity, without finishing the heated air supplying step (S 655 ). As mentioned above, if the relative humidity measured in the initial stage of the drying is relatively high to set the target relative humidity to be relatively high, the drying might be finished with the laundry having the water too much. The above step may prevent this insufficient drying. As a result, the control part supplies the heated air continuously until the measured relative humidity is lowered to reach the target maximum humidity or lower, even in case it reaches the target relative humidity or lower. The control part finishes the heated air supplying when the measured relative humidity is the target relative humidity or lower, by extension, the target maximum humidity or lower (S 657 ). 
     In the meanwhile, the control part compares the measured relative humidity with the target minimum humidity when the measured relative humidity is the target relative humidity or higher (S 659 ). In case the relative humidity measured initially is relatively low to set the target relative humidity to be too low, the relative humidity reaches the target minimum humidity set according to the courses before reaching the target relative humidity. In this case, the control part finishes the heated air supplying step to prevent the over-drying for the laundry. When the measured relative humidity is the target minimum humidity or lower even in case the measured relative humidity fails to reach the target relative humidity, the control part determines that the drying is completed and it finishes the heated air supplying to complete the heated air supplying step (S 657 ). 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. 
     INDUSTRIAL APPLICABILITY 
     The present invention has an industrial applicability. 
     The control method including the above steps may detect the relative humidity in the initial stage of the drying, when setting the target relative humidity used to determine the completion of drying, and it may set the target relative humidity based on the measured relative humidity. As a result, it is possible to remove deviation of the amount of water remaining in the laundry after completing the drying, regardless of the laundry amount.