Patent Publication Number: US-2009235553-A1

Title: Laundry Dryer

Description:
TECHNICAL FIELD 
     The present invention relates to a laundry dryer. More specifically, the present invention relates to a laundry dryer capable of removing and/or preventing wrinkles of laundry. 
     BACKGROUND ART 
     Laundry dryers are typically electric appliances that dry washed laundry, mainly washed clothes, by using high temperature air. In general, a laundry dryer is configured of a drum, a driving source, heating means and a blower unit. Laundry is held in the drum and the driving source drives the drum. The heating means heats air drawn in the drum. The blower unit sucks or discharges the air inside the drum. 
     Laundry dryers may be categorized, based on a method of heating air that is heating means, into electric-type laundry dryers and gas-type laundry dryers. In an electric-type laundry dryer, air is heated by using electric resistance heat. While, in a gas-type laundry dryer, air is heated by using heat generated from gas combustion. On the other hand, laundry dryers may be categorized into condensation-type laundry dryers and exhaustion-type laundry dryers. In a condensation-type laundry dryer, air is heat-exchanged with laundry in the drum and the damp air is circulated, not discharged outside, to be heat-exchanged with external air at an auxiliary condenser. At this time, water is condensed and discharged outside. In an exhaustion-type laundry dryer, air is heat-exchanged with laundry in the drum and the damp air is directly discharged outside the laundry dryer. Also, laundry dryers may be categorized, based on a method of loading laundry, into top loading-type laundry dryers and front loading-type laundry dryers. In a top loading-type laundry dryer, laundry is loaded into the drum through a top of the laundry dryer. In a front loading-type laundry dryer, laundry is loaded into the drum through a front of the laundry dryer. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     However, above conventional laundry dryers may have following problems. 
     Commonly, the laundry having performed washing and spinning is loaded and dried in the conventional laundry dryers. In a view of a principle of water washing, washed laundry has wrinkles and the wrinkles created during the washing and spinning are not removed during the drying. As a result, auxiliary ironing is necessary in the conventional laundry dryer to remove the wrinkles, which causes a problem. 
     Moreover, in case that clothes rather than the washed laundry are kept and used, the clothes like the washed laundry may have wrinkles, crumples and fold marks (hereinafter, referenced to as wrinkles ). Accordingly, there have been demands for development of devices capable of removing wrinkles easily even after common usage and keeping. 
     Technical Solution 
     To solve the problems, an object of the present invention is to provide a laundry dryer that can prevent and/or remove wrinkles of laundry. 
     Another object of the present invention is to provide a laundry dryer and a control method thereof, which can drain salt water remaining after regenerating a water softening member conveniently. 
     To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a laundry dryer includes a drum to hole laundry; a steam generator to selectively supply steam to the drum; a water supply source to hold water that is supplied to the steam generator; a water softening member provided in the water supply source to soften water, and a drain hose through which the water of the water supply source is selectively drained outside. 
     Here, the water softening member may include an ion exchange resin. Specifically, the water softening member may include a lower housing provided in the water supply source, the lower housing having a plurality of through-holes; an upper housing detachable from the lower housing, the upper housing having a plurality of through-holes, wherein the ion exchange resin is filled up in a predetermined space formed by the upper and lower housing. 
     The laundry dryer may further include a lime sensor to sense an amount of lime dissolved in the water of the water supply source; a warning part to warn a user more than a predetermined amount of lime if more than a predetermined amount of lime is sensed by the lime sensor; and a controller to control the lime sensor and the warning part. 
     It is preferable that the laundry dryer further includes a regeneration operation instructing part to transmit a signal to the controller if the ion exchange resin starts to be regenerated. 
     Here, it is preferable that the controller controls the water inside the water supply source to be drained through the drain hose, not to be supplied to the steam generator, if controller receives the signal from the regeneration operation instructing part. 
     The drain hose may be directly connected to the water supply source. It is preferable that the laundry dryer further includes a valve to selectively open and close a path to the drain hose. As a result, the controller controls the valve to be opened if the controller receives the signal from the regeneration operation instructing part. 
     The laundry dryer may further include a pump to supply the water held in the water supply source to the steam generator. In this case, the drain hose is provided between the steam generator and the pump. The drain hose may include a first valve provided between the steam generator and the pump and a second valve provided at the drain hose. As a result, the controller controls to close the first valve and to open the second valve if the controller receives the signal from the regeneration operation instructing part. 
     On the other aspect of the present invention, a control method of a laundry dryer having a steam generator to supply steam to a drum holding laundry, a water supply source to hold water to supply water to the steam generator and a water softening member, having an ion exchange resin, provided in the water supply source to soften the water, the method includes a sensing step to sense an amount of lime dissolved in the water of the water supply source; a warning step to warn a user more than a predetermined amount of lime, if more than predetermined amount of lime is sensed; a regenerating step to regenerate the ion exchange resin: and a draining step to drain the water of the water supply source outside if the ion exchange resin is regenerated. 
     ADVANTAGEOUS EFFECTS 
     The present invention has an advantageous effect of preventing and/or removing wrinkles of laundry efficiently. 
    
    
     
       BRIEF DESCRIPTION OF THE 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 an exploded perspective view illustrating an embodiment of a laundry dryer according to the present invention; 
         FIG. 2  is a longitudinally sectional view of  FIG. 1 ; 
         FIG. 3  is a sectional view illustrating a steam generator shown in  FIG. 1 ; 
         FIG. 4  is a perspective view schematically illustrating another embodiment of a laundry dryer according to the present invention; 
         FIG. 5  is an exploded perspective view illustrating an example of a water supply source shown in  FIG. 4 ; 
         FIG. 6  is an exploded perspective view illustrating a water softening member shown in  FIG. 5 ; 
         FIG. 7  is a diagram illustrating another embodiment of a laundry dryer according to the present invention; and 
         FIG. 8  is a block view schematically illustrating a control system of the laundry dryer according the embodiments of the present invention. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     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. 
     To explain a laundry dryer according to the present invention, a top loading-type, electric-type and exhaustion-type laundry dryer will be presented as examples on convenience sake. However, the present invention is not limited to the above examples and it can be applicable to a front loading-type, gas-type and condensation-type laundry dryer. 
     In reference to  FIGS. 1 and 2 , an embodiment of the laundry dryer according to the present invention will be explained. 
     A cabinet  10  defines an exterior appearance of the laundry dryer and a drum  20  is rotatable in the cabinet  10 . A motor  70  and a belt  68  drive the drum  20 . A hot air heater  90  is provided in a predetermined portion of the cabinet  10  to heat air and to create high temperature air (hereinafter, hot air). A hot air supply duct  44  is provided in a predetermined portion of the cabinet  10  to supply the hot air of the hot air heater  90  to the drum  20 . Also, there are provided an exhaustion duct  80 , a blower unit  60  in the laundry dryer according to the present invention. The damp air heat-exchanged with the laundry in the drum  20  is discharged outside the drum  20  through the exhaustion duct  80  and the blower unit  60  sucks the damp air. A steam generator  200  is provided in a predetermined portion of the cabinet  10  to generate high temperature steam. This embodiment presents on convenience sake an indirect drive type in that the drum  20  is rotated by the motor  700  and the belt  68  and the present invention is not limited thereto. That is, it is possible to apply to the present invention a direct drive type in that the drum  20  is directly rotated by connecting the motor  70  to a rear surface of the drum  20 . 
     Each configuration will be explained in detail. 
     The cabinet  10  defines an exterior appearance of the laundry dryer and it includes a base  12 , a pair of side covers  14 , a front cover  16 , a rear cover  18  and a top cover  17 . The base  12  forms a bottom surface of the laundry dryer and the side covers  14  are perpendicular to the base  12 . The front cover  16  and the rear cover  18  are installed in a front portion and a rear portion of the side covers  14 , respectively. The tope cover  17  is installed in an upper portion of the side covers  14 . A control panel  19  having various operational switches is positioned at the top cover  17  or the front cover  16  and the door  164  is coupled to the front cover  16 . An air inlet  182  and an air outlet  184  are provided at the rear cover  18 . External air is drawn through the air inlet  182  and the air inside the drum  20  is discharged outside through the air outlet  184  that is a final path to an outside. 
     An inner space of the drum  20  is employed as a drying chamber for drying the laundry. It is preferable that a lifter  22  is installed in the drum  20  to lift and drop the laundry, such that the laundry is turned over to enhance drying efficiency. 
     On the other hand, a front supporter  30  is provided between the drum  20  and the cabinet  10 , in other words, between the drum  20  and the front cover  16 . A rear supporter  40  is provided between the drum  20  and the rear cover  18 . The drum  20  is rotatable between the front supporter  30  and the rear supporter  40 , and sealing members (not shown) for preventing water leakage are coupled between the front supporter  30  and the drum  20  and between the drum  20  and the rear supporter  40 , respectively. The front supporter  30  and the rear supporter  40  of the drum  20  close a front and a rear surface, respectively, to support a front and rear end of the drum  20  as well as to form the drying chamber. 
     An opening is formed at the front supporter  30  to communicate the drum  20  with an outside and the opening is selectively opened and closed by the door  164 . In addition, a lint duct  50  as a path through which the air in the drum  20  flows outside is connected to the front supporter  30  and a lint filter  52  is installed at the lint duct  50 . A predetermined portion of the blower unit  60  is connected to the lint duct  50  and the other opposite predetermined portion of the blower unit  60  is connected to the exhaustion duct  80 . Here, the exhaustion duct  80  is in communication with the air outlet  184  provided at the rear cover  18 . As a result, once the blower unit  60  is operated, the air inside the drum  20  flows through the lint duct  50 , the exhaustion duct  80  and the air outlet  184  in order, only to be exhausted outside. At this time, foreign substances including lint are filtered by the lint filter  52 . Commonly, the blower unit  60  is configured of a blower  62  and a blower housing  64 . The blower  64  is commonly connected to the motor  70  for driving the drum  20 . 
     An opening  42  formed of plural through-holes is formed at the rear supporter  40  and the hot air supply duct  44  is connected to the opening  42 . The hot air supply duct  44  is in communication with the drum  20  and it is employed as a path for supplying hot air to the drum  20 . For that, the hot air heater  90  is mounted in a predetermined portion of the hot air supply duct  44 . 
     On the other hand, the steam generator  200  is provided in a predetermined portion of the cabinet  10  to generate steam and the generated steam is supplied to the drum  20 . In reference to  FIG. 3 , the steam generator  200  will be explained in detail. 
     The steam generator  200  is configured of a tank  210 , a heater  240 , a water level sensor  260  and a temperature sensor  270 . Water is held in the tank  210  and the heater  240  is mounted in the tank  210 . The water level sensor  260  senses water levels in the steam generator  200  and the temperature sensor  270  senses temperatures in the steam generator  200 . The water level sensor  260  is configured of a common electrode  262 , a low water level electrode  264  and a high water level electrode  266 . A high water level is sensed based on whether an electric current is applied between the common electrode  262  and the high water level electrode  266 , and a low water level is sensed based on whether an electrode current is applied between the common electrode  262  and the low water level electrode  264 . 
     A water supply hose  220  is connected to a predetermined portion of the steam generator  200  and a steam hose  230  is connected to the other opposite predetermined portion of the steam generator  200 . Here, it is preferable that a nozzle  250  having a predetermined shape is provided at a front end of the steam hose  230 . An end of the water supply hose  220  is typically connected to an external water supply source such as a water tap. The nozzle  250 , that is, a steam outlet is positioned at a predetermined portion in the drum  20  to spray steam in the drum  20 . 
     In the meantime, this embodiment presents a kind of the steam generator  200  in that the heater  240  heats the water in the tank  210  to generate steam (called as tank heating type steam generator on convenience sake) and the present invention is not limited thereto. That is, any devices capable of generating steam may be applicable to the present invention. For example, a kind of a steam generator in that a heater is directly installed around a water supply hose to heat the water in the water supply hose, without storing water in a predetermined space, (called as a pipe heating type steam generator) may be applicable to the present invention. 
     In reference to  FIG. 4 , another embodiment of a laundry dryer according to the present invention will be explained. This embodiment presents that the water supply source may be detachable. The water supply source might be a water tap like in the above embodiment and its installation structure may be complex in this case, because additional installation of various devices is necessary. To solve the problem, water is supplied by using a detachable water supply source  300  in this embodiment and the detachable water supply source  300  filled with water is connected to a water supply path, that is, a water supply hose  220 , which is quite convenient. 
     In addition, a pump  400  may be provided between the water supply source  300  and the steam generator  200 . It is preferable that the pump  400  is rotatable in a clockwise and counter-clockwise direction and that the pump  400  allows water to be supplied to or drained from the steam generator  200 . It is possible to supply water to the steam generator  200  by using water level difference between the water supply source  300  and the steam generator  200 . However, this case results in lack of structural space, because it is common that various parts of dryers are standardized goods compactly designed. As a result, the water supply using the water level difference is substantially impossible unless the sizes of conventional dryer parts are changed. While, if a small sized pump  400  is used, there may be enough space for the steam generator  200  without changing the sizes of the parts and this is very advantageous to use the pump  400  according to the present invention. If the steam generator  200  is not used for a relatively long time, the heater might be damaged by remaining water or polluted water might be used later. Thus, it is preferable that the remaining water in the steam generator  200  is drained. 
     While water is supplied or steam is discharged through the upper portion of the steam generator  200 , it is preferable that water is supplied to the steam generator  200  through a lower portion of the steam generator  200  and that steam is discharged from the steam generator  200  through the upper portion of the steam generator  200  in this embodiment. In this case, it is convenient to drain the remaining water in the steam generator  200 . In addition, it is preferable that a safety valve  500  is provided at a steam path through which steam is discharged from the steam generator  200  and the steam path is a steam hose  230 . 
     Each configuration will be explained in detail. 
     First of all, in reference to  FIG. 5 , the detachable water supply source  300  (hereinafter, a cartridge) will be explained. 
     The cartridge  300  includes a lower housing  310  that substantially holds water and an upper housing  320  detachable from the lower housing  310 . As a result, it is easy to wash and clean slime inside the cartridge  300 . Also, it is easy to separate, clean and regenerate filters  330  and  340  and a water softening member  350 . 
     It is preferable that a first filter  330  is provided at the upper housing  320 . That is, the first filter  330  is installed at a water inlet of the upper housing  320  and water is primarily filtered when supplied to the cartridge  300 . 
     A closable member  360  is provided at the lower housing  310  to selectively supply the water of the cartridge  300  outside. If the cartridge  300  is separated, the water of the cartridge  300  is not discharged outside and if the cartridge  300  is installed, the water is discharged outside. A second filter  360  for filtering the water may be connected to the closable member  360  and it is preferable that the second filter  360  is detachable. As a result, impurities mixed with water such as minute dirt may be filtered doubly. The first filter  330  may be formed of an approximately  50  mesh net and the second filter  340  may be formed of an approximately  60  mesh net. Here, the  50  mesh net means that the mesh number per a predetermined section is  50 . As a result, a size of each mesh hole forming the first filter  330  is larger than a size of each mesh hole forming the second filter  340 , such that relatively large impurities are filtered by the first filter  330  primarily and relatively small foreign impurities are filtered by the second filter secondarily. 
     It is preferable that a water softening member  350  is provided in the cartridge  300  to soften water. It is also preferable that the water softening member  350  is detachable. 
     As shown in  FIG. 6 , the water softening member  350  includes a lower housing  352  having a plurality of holes and an upper housing  353  having a plurality of holes, being detachable from the lower housing  352 . In addition, the water softening member  350  may further include an ion exchange resin (not shown) filled in a predetermined space defined by the upper housing  353  and lower housing  352 . 
     The reason why the water softening member  350  is used will be described. If the water supplied to the steam generator  200  has a high degree of hardness, Ca (HCO 3 ) 2  dissolved in the water is heated and CaCO 3  is educed. Thus corrosion of the heater might be caused by lime. Especially, this corrosion might be severe in Europe and America continents, because water in those areas is soft water having a high degree of hardness. Thus, it is preferable in those areas that calcium, magnesium and the like are removed by the ion exchange resin to prevent eduction of lime. The efficiency of the ion exchange resin deteriorates as a water softening process being performed and thus the ion exchange resin is regenerated in a predetermined time period to reuse the ion exchange resin. Here, the ion exchange resin may be regenerated by using an ion exchange resin regenerator. Calcium decomposer, for example, sodium chloride (NaCl) may be used as the ion exchange resin generator. Next, NaCl will exampled as calcium decomposer on convenience sake. A water softening process by using the ion exchange is 2(R—SONa)+Ca2&lt;−&gt;(R—SO)Ca+2N and a ion exchange resin regenerating process by using NaCl as Calcium decomposer is (R—So)Ca+SNaCl&lt;−&gt;2(R—SONa)+CaCl. 
     On the other hand, once salt (sodium chloride-NaCl) is supplied to the cartridge  300  having the water softening member  350  and the softening member  350  is regenerated, the remaining sodium chloride dissolved in the water should be drained outside. In reference to  FIG. 7 , a structure for this drainage will be explained. 
     A drain hose  480  is connected between the pump  400  and the steam generator  200  to drain the remaining salty water outside the cartridge  300 . A first valve  482  is provided between the pump  400  and the steam generator  200 , especially, at an end of the drain hose  480  toward the steam generator  200  to selectively close a path of the drain hose  480 , especially, a path between the pump  400  and the steam generator  200 . A second valve  484  is provided at a predetermined portion of the drain hose  480  to selectively close a path of the drain hose  480 . It is preferable that the first and second valve  482  and  484  is configured of a solenoid valve for control convenience. 
     To inform a user of a time for regenerating the water softening member, a lime sensor, a regeneration warning part and a regeneration operation instructing part may be further provided. If more than a predetermined amount of lime is sensed by the lime sensor, the regeneration warning part warns a user that the lime is sensed. 
     This control configuration may be embodied variously and an embodiment thereof will be explained in reference to  FIG. 8 . 
     The lime sensor  610  and the regeneration operation command part  620  are connected to an input terminal of a controller  600 . Here, the regeneration operation instructing part  620  instructs a regeneration operation of the ion exchange resin. The valves  482  and  484 , the regeneration warning part  630  and the pump  400  are connected to an output terminal of the controller  600 . That is, once the lime sensor  610  senses more than the predetermined amount of lime, the controller  600  warns a user that the ion exchange resin should be regenerated by using the regeneration warning part  630 , for example, raising an alarm or turning on/off a warning lamp. Hence, if a user selects the regeneration operation instructing part  620 , the controller  600  controls the valves  482  and  484  appropriately. 
     In reference to  FIGS. 7 and 8 , an operation of the above embodiment will be described. 
     A path of the steam generator  200  is opened and a path of the drain hose  480  is closed during a common operation of the dryer. As a result, the water of the cartridge  300  is supplied to the steam generator  200 . 
     If more than the predetermined amount of lime is sensed by the lime sensor  620 , the controller  600  operates the regeneration warning part  630  to warn a user by using an alarm that lime is sensed. At this time, the user introduces a regenerator, for example, salt (Sodium chloride-NaCl) into the cartridge  300  and the ion exchange resin is regenerated. When regenerating the ion exchange resin, the water of the cartridge  300  should not be drained into the drum or outside. Once completing the regeneration of the ion exchange resin, it is preferable that the water dissolved with the salt is drained outside the cartridge  300 . This drain prevention and drain may be performed by controlling the valves  482  and  484 . A method of controlling the valves  482  and  484  may be varied and a preferred embodiment will be described. A normal-on-type valve that is usually opened is used for the first valve  482  and a normal-off-type valve that is usually closed is used for the second valve  484 . This is because the water supply to the steam generator  200  should be performed during the operation of the dryer and the water drainage to an outside should be performed intermittently. In case of the above type of valve usage, a user pushes the regeneration operation instructing part  620  when the regeneration of the ion exchange resin starts. Hence, the controller  600  receiving the regeneration instruction operates the second valve  484  to be opened and operates the pump  400  to drain the water outside the cartridge  300 . 
     On the other hand, if the types of valves  482  and  484  are changed, the valves  482  and  484  are controlled accordingly. For example, if both of the valves  482  and  484  are normal on types, the first valve  482  is opened and the second valve  484  is closed during the common operation of the dryer, and the first valve  482  is closed and the second valve  484  is opened during the ion exchange resin regeneration mode. That is, the path to the steam generator  200  is closed and the path to the drain hose  480  is opened to drain the salt water outside the cartridge  300  through the drain hose  480 . 
     If the drain hose  480  is used in this embodiment, the water of the cartridge  300  as well as the salt water remaining after the regeneration of the water softening member may be drained outside. That is, in case that the dryer has not been used for a relatively long time, the water of the cartridge  300  may be drained outside through the drain hose  480  without separating the cartridge  300 . 
     Alternatively, unlike the above embodiment, the salt water of the cartridge  300  may be drained without using the pump  400 . For example, the drain hose  480  for draining the salt water remaining after the regeneration of the water softening member may be directly connected to the cartridge  300  and the remaining salt water may be directly drained outside by using the drain hose  480 . If then, the drain hose  480  may be positioned at the cartridge  300  or between the cartridge  300  and the pump  400 . Here, it is preferable that a valve is provided at the drain hose  480  to selectively open and close a path. 
     According to experiments performed by the inventor, although there is difference according to kinds of fabrics and humidity of the laundry, there is an effect of removing and preventing wrinkles in the present invention. For example, wrinkles of the laundry washed in a washer may be removed and the present invention is applicable to various kinds of laundry. For example, clothes worn for about a day, that is, dried laundry with fewer wrinkles may be used in the present invention. In other words, the laundry dryer according to the present invention may be used as a kind of wrinkle removal apparatus. 
     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. 
     First, the laundry dryer according to the present invention has an effect of efficiently preventing wrinkles of the dried laundry in advance. In addition, the laundry may be sterilized and bad smell of the laundry may be removed. 
     Furthermore, the laundry dryer according to the present invention has another advantageous effect of efficiently removing wrinkles of the dried laundry without auxiliary ironing. 
     A still further, the laundry dryer according to the present invention has a further advantageous effect of a simple structure, because an external water tap is not connected to the steam generator provided in the laundry dryer.