Patent Publication Number: US-9903652-B2

Title: Clothes treating apparatus having drying function

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Pursuant to 35 U.S.C. § 119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2012-0004422, filed on Jan. 13, 2012, the contents of which is incorporated by reference herein in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This specification relates to a clothes treating apparatus having a drying function capable of drying clothes and the like, and particularly, to a clothes treating apparatus having a drying function capable of fast drying a large quantity of targets to be dried by employing a heater assembly, separate from a cabinet having a drum and the like therein, for drying such large quantity of targets to be dried. 
     2. Background of the Invention 
     In general, a clothes treating apparatus refers to an apparatus having at least one of a dehydrating function and a drying function for clothes. For example, a drying machine as one of clothes treating apparatuses is an apparatus for drying a target to be dried by introducing the target to be dried into a drum and evaporating moisture contained in the target with supplying air into the drum. A washing machine having a drying function is an apparatus capable of drying clothes, which has been dehydrated after washed, with hot air. 
     A typical dryer includes a drum rotatably installed within a main body or a cabinet and receiving clothes therein, a driving motor for driving the drum, a blower fan for generating the flow of air supplied into the drum or discharged from the drum, and a heating unit for heating up the air introduced into the drum. The heating unit may be implemented as a heater type which uses high temperature electric resistance heat generated by electrical resistance or heat of combustion generated by burning gas. 
     In the meantime, air discharged out of the drum contains moisture from the clothes within the drum, to become air in a state of high temperature and high humidity. Here, dryers may be classified, according to how to process such hot humid air, into a circulating type in which hot humid air is cooled below a dew point temperature through a heat exchanger while circulating without being discharged out of a dryer such that moisture contained within the hot humid air can be condensed to be resupplied, and an exhausting type in which hot humid air passed through a drum is discharged directly to the outside. 
     The aforementioned typical dryer includes a drum, a driving motor, a blower fan and a heater all disposed within a single main body. Hence, a size of a cabinet or main body and sizes of elements such as the driving motor and the heater are decided depending on the size of the drum. 
     Here, a capacity of a dryer depends on not only the size of the drum but also a quantity of air supplied into the drum and a quantity of heat or energy to be supplied by the heater. Therefore, even if the drum is large in size, if air and heat are not sufficiently supplied, a drying performance of the dryer does not come up to the size of the drum. Also, even for a drum of the same size, if air and heat are fully supplied into the drum, the drying performance of the dryer may be more improved. 
     A household clothes dryer is installed within a limited space, which results in a limited size of a main body of the dryer. Accordingly, the size of the blower fan and the size of the heater are limited. Hence, a drying capacity of the dryer is limited, but there is not a problem because of less necessity of using a capacity more than that. 
     However, a dryer which is used in a commercial place such as a laundromat or an industrial dryer must have a capacity, which is large enough to dry a large quantity of clothes. Therefore, a dryer with a large capacity has to be used. 
     To dry the large quantity of clothes, the main body of the dryer may have an increased size and accordingly the blower fan and the heater as well as the drum may also be fabricated with large sizes. Here, a separate dryer main body is fabricated for the industrial dryer, unlike the household clothes dryer. That is, the main body of the household clothes dryer is unable to be used in the industrial dryer. Consequently, a manufacturer has to produce a separate dryer main body, and a user is unable to use the dryer main body which is being used at home. 
     SUMMARY OF THE INVENTION 
     Therefore, the present disclosure is to solve the problems of the related art. 
     An aspect of the detailed description is to provide a clothes treating apparatus having a drying operation, capable of drying a large quantity of clothes by connecting a large heater and a large blower fan to a random clothes treating apparatus. 
     Especially, an aspect of the detailed description is to provide a clothes treating apparatus having a drying operation, capable of drying a large quantity of clothes using a large heater and a large blower fan, irrespective of a size of a main body of the apparatus, by virtue of employing a module part, separate from a cabinet having a drum and the like therein. 
     Another aspect of the detailed description is to provide a clothes treating apparatus having a drying operation, capable of reducing requirement for producing a separate cabinet due to being connectable to a random clothes treating apparatus, thereby increasing generality and usability and reducing fabricating costs. 
     Another aspect of the detailed description is to provide a clothes treating apparatus having a drying operation, capable of realizing a structural stability by virtue of a structure that a separate module part does not affect a rear portion of a cabinet of the apparatus even if the separate module part is connected to the cabinet. 
     Another aspect of the detailed description is to provide a clothes treating apparatus having a drying operation, capable of increasing a quantity of air used for drying a large quantity of clothes by supplying air heated by a heat assembly into a drum of a main body of the apparatus without a loss, even if a separate module part is provided, and also capable of allowing the module part to be connected to a cabinet of a random clothes treating apparatus. 
     Another aspect of the detailed description is to provide a clothes treating apparatus having a drying operation, capable of exhibiting improved operation efficiency and stability. 
     Another aspect of the detailed description is to provide a clothes treating apparatus having a drying operation, capable of improving efficiency by allowing a first thermostat to turn a heater module off only when external air is not smoothly introduced, so as to prevent the heat module from being unnecessarily turned off by the first thermostat. 
     Another aspect of the detailed description is to provide a clothes treating apparatus having a drying operation, capable of improving convenience in operation and spatial efficiency by allowing a mounting position of a first thermostat to be easily decided and the first thermostat to be installed near a heater. 
     Another aspect of the detailed description is to provide a clothes treating apparatus having a drying operation, capable of improving generality and usability by allowing for mounting a module part without using a separate connection member even when a plurality of clothes treating apparatuses are installed in a stacking manner for increasing a spatial usage. 
     To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, there is provided a clothes treating apparatus having a drying function, the apparatus including a cabinet to receive a rotatable drum therein, the cabinet defining an appearance of the apparatus, a module part mounted onto an outer surface of the cabinet and having a heater assembly, a blower assembly and a housing, and a link unit to connect the module part onto the rear side of the cabinet. Here, the housing may receive the heater assembly and the blower assembly therein. 
     In the clothes treating apparatus, air to be used for drying in the drum may be supplied into the drum after being heated through the heater assembly, and air used for drying in the drum may be externally discharged via the blower assembly. 
     With the configuration, the heater assembly and the blower assembly are separately disposed as a module part at the outside of the cabinet. Accordingly, a large heater and a large blower fan may be used regardless of the size of the cabinet of the apparatus, allowing for drying a large quantity of clothes or laundry. In addition, the module part may be connectable to a random apparatus, which may reduce requirement for fabricating a separate cabinet of the apparatus, resulting in improvement of generality and usability and reduction of fabricating costs. 
     Here, external air introduced into the housing may be transferred to the heater assembly. 
     In accordance with one exemplary embodiment, the air used for drying in the drum may be discharged to a front lower side of the drum, and then transferred to the blower assembly after removing foreign materials therefrom. 
     In accordance with one exemplary embodiment, the link unit may comprise a pair of support frames to connect the cabinet to both side surfaces of the module part, and a plurality of guide frames to support the support frames in the connected state. 
     In accordance with one exemplary embodiment, the cabinet may include a rear panel defining a rear surface of the apparatus, and the link unit may connect the module part to the cabinet regardless of the shape of the rear panel. 
     Accordingly, even if a separate module part is connected to the cabinet, it may not affect the rear panel of the cabinet, thereby providing the apparatus with structural stability. 
     In accordance with one exemplary embodiment, the apparatus may further include a connecting duct to communicate the drum with the heater assembly of the module part, so as to allow for a smooth connection between the cabinet and the module part. Here, the drum may include a drum back defining a rear surface thereof, and the connecting duct may be connected to the drum back through the rear panel. 
     In accordance with one exemplary embodiment, the connecting duct may include a sealing unit allowing the heated air supplied by the heater assembly to be supplied only into the drum via the drum back. 
     In accordance with one exemplary embodiment, the sealing unit may include a sealing member to seal a circumference of the connecting duct, and a sealing bead disposed at an outside of the sealing member to seal the circumference of the connecting duct. 
     With the configuration, a quantity of air to be used for drying a large quantity of clothes may increase by supplying air heated by the heat assembly into the drum without a loss, even if a separate module part is provided, and also the module part may be connectable to a cabinet of a random clothes treating apparatus, thereby improving generality and usability of the apparatus. 
     In accordance with one exemplary embodiment, the apparatus may further comprise an exhaust duct to allow air discharged from the drum to flow into the blower assembly. Also, the link unit may include a duct support frame disposed between the rear panel and the blower assembly to support the exhaust duct. 
     With the configuration, a large quantity of air may be supplied into the blower assembly of the module part so as to increase the quantity of air to be used for drying a large quantity of clothes. Also, the module part may be connectable to a cabinet of a random clothes treating apparatus, thereby improving generality and usability of the apparatus. 
     In accordance with one exemplary embodiment, the blower assembly may include a blower casing, a blower fan disposed within the blower casing, and an exhaust port. Air discharged from the drum via the exhaust duct may be discharged through the blower fan. 
     In accordance with one exemplary embodiment, at least part of air discharged to the outside through the blower assembly may be transferred to the heater assembly. 
     In accordance with one exemplary embodiment, the apparatus may further include a bypass unit disposed between the exhaust port and the heater assembly to supply at least part of air discharged through the exhaust port into the heater assembly. 
     In accordance with one exemplary embodiment, the heater assembly may include a heater casing, and a heater module as an air heating device disposed within the heater casing, and the bypass unit may include a bypass duct to communicate the exhaust port with the heater casing. Here, in accordance with one exemplary embodiment, the bypass unit may further include a distributing member to distribute an amount of air transferred from the bypass duct to the heater module. 
     With the configuration, the air discharged from the drum may partially be recycled, which may allow for reduction of a heating time, resulting in improvement of efficiency of the heater assembly and reduction of power consumption. 
     In accordance with one exemplary embodiment, the heater assembly may include a heater casing, a heater module as an air heating device disposed within the heater casing, and brackets to mount the heater module within the heater casing. 
     In accordance with one exemplary embodiment, each of the brackets may include a plurality of mounting ribs to assist the heater module to be mounted onto a uniform mounting position. The plurality of mounting ribs may be spaced apart from each other by uniform intervals. 
     Accordingly, the installation efficiency of the heater module may be improved, which may result in enhancement of operation efficiency and stability of the apparatus. 
     In accordance with one exemplary embodiment, the heater assembly may further include a first thermostat installed adjacent to an outlet side of the heater module to turn the heater module on or off according to air temperature, and a slit formed between the first thermostat and the heater module to allow for introduction of external air therethrough. 
     The slit may introduce external air therethrough to form a blocking flow by the external air so as to block air heated by the heater module from contacting the first thermostat. In addition, in accordance with one exemplary embodiment, the heater assembly may further include a passage guide to guide the flow path of the external air introduced through the slit. 
     With the configuration, to prevent the first thermostat from unnecessarily turning the heater module off, the thermostat may be allowed to turn the heater module off only when external air is not smoothly introduced. This may result in improvement of efficiency of the apparatus. 
     In accordance with one exemplary embodiment, the heater assembly may further include a middle plate to prevent radiant heat from being transferred from the heater module into the drum. Also, the heater casing may include at least one air inlet port to supply external air into the heater module. 
     In accordance with one exemplary embodiment, the housing may include at least one air inlet port to supply external air into the heater assembly. 
     In accordance with one exemplary embodiment, the housing may include a lower surface and an upper surface. Here, the lower surface and the upper surface may have the same shape as each other, and the lower surface may be coupled with legs for supporting the module part from the ground. 
     Here, the cabinet may be provided in plurality which are connected in a perpendicular direction, and the module part may also be provided in plurality. Accordingly, the plurality of module parts may be coupled to the cabinets connected in the perpendicular direction, respectively. 
     A lower surface of a housing of an upper module part and an upper surface of a housing of a lower module part, of the plurality of module parts coupled to each other, may be coupled to each other by supporting bolts and nuts with maintaining an interval therebetween. 
     With the configuration, even when a plurality of apparatuses are used in a stacked state to have high spatial efficiency, the module parts may be mounted without use of a separate coupling member, resulting in improvement of generality and usability of the apparatus. 
     The present disclosure having the configurations may provide the following effects. 
     A module part having a heater assembly and a blower assembly may be employed, separate from a cabinet of a clothes treating apparatus. This may allow for use of a large heater and a large blower fan, irrespective of a size of a main body of the apparatus, thereby enabling the clothes treating apparatus to dry a large quantity of clothes. 
     Also, since a first thermostat is allowed to turn the heater module off only when external air is not smoothly introduced, the heater module may be prevented from being unnecessarily turned off by the first thermostat, improving efficiency of the apparatus. 
     A mounting position of the first thermostat may be easily decided and be located adjacent to a heater, thereby improving convenience in operation and spatial efficiency. 
     In addition, a bypass unit may further be employed to bypass a part of air, which is externally discharged from the blower assembly, toward the heater assembly, thereby reducing power consumption by the heater module and a drying time of the apparatus during a drying operation. 
     Also, even when a plurality of apparatuses are used in a stacked state to have high spatial efficiency, the module parts may be mounted without use of a separate coupling member, resulting in improvement of generality and usability of the apparatus. 
     Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments and together with the description serve to explain the principles of the invention. 
       In the drawings: 
         FIG. 1  is a schematic view of a clothes treating apparatus having a drying operation in accordance with one exemplary embodiment; 
         FIG. 2  is a schematic view showing a module part mounted within a cabinet of the dryer and a link unit for mounting the module part; 
         FIG. 3  is a sectional view showing that a heater assembly communicates with a drum via a connecting duct; 
         FIG. 4  is an enlarged sectional view showing the connecting duct in detail; 
         FIG. 5  is a disassembled perspective view of a housing of the module part; 
         FIG. 6  is a disassembled perspective view of the heater assembly; 
         FIG. 7  is a perspective view of a bracket for securing a heater module to a heater casing; 
         FIG. 8  is a perspective view showing a state that the heater module is coupled to the bracket; 
         FIG. 9  is a schematic view showing that a first thermostat is coupled to the heater assembly; 
         FIG. 10  is a schematic view showing that a shielding passage is formed by the first thermostat and a slit; 
         FIG. 11  is a schematic view showing a blower assembly; 
         FIG. 12  is a disassembled perspective view showing a link unit; 
         FIG. 13  is a schematic view showing a state that the link unit is partially coupled to a rear panel; 
         FIG. 14  is a schematic view showing a duct support frame for supporting an exhaust duct; 
         FIG. 15  is a schematic view showing an air flow in accordance with the one exemplary embodiment; 
         FIG. 16  is a rear perspective view of a clothes treating apparatus having a drying operation in accordance with another exemplary embodiment; 
         FIG. 17  is an enlarged perspective view of an air introduction portion of a heater assembly shown in  FIG. 16 ; 
         FIG. 18  is a sectional view taken along the line I-I of  FIG. 16 ; 
         FIG. 19  is a graph showing temperature of air transferred from the heater assembly into a drum in accordance with the one exemplary embodiment shown in  FIG. 1 ; 
         FIG. 20  is a graph showing temperature of air transferred from a heater assembly into a drum in accordance with the another exemplary embodiment shown in  FIG. 16 ; 
         FIG. 21  is a schematic view showing a stacked state of a plurality of clothes treating apparatuses having a drying operation in accordance with one exemplary embodiment; and 
         FIGS. 22 and 23  are schematic views showing a connected state of module parts of the plurality of the clothes treating apparatuses stacked on each other. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Description will now be given in detail of the exemplary embodiments, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components will be provided with the same reference numbers, and description thereof will not be repeated. 
       FIG. 1  is a schematic view of a clothes treating apparatus having a drying function in accordance with one exemplary embodiment. This exemplary embodiment illustrates a drying machine. However, the present disclosure may not be limited only to the drying machine, but applicable to a clothes treating apparatus, for example, a washing machine having a drying function and the like, which dries clothes by supplying air or hot air into a drum. 
     As shown in  FIG. 1 , a dryer according to one exemplary embodiment may include a main body  100  having a rotatable drum within a cabinet, a module part  200  having a heater assembly and a blower assembly and connectable to the rear of the cabinet, and a link unit  300  for connecting the module part onto the rear of the cabinet. 
     The main body  100  of the dryer may include a cabinet  101  defining an appearance of the dryer, a drum  110  rotatably installed within the cabinet  101 , and a door  120  mounted onto a front surface of the cabinet  101 . 
     The cabinet  101  shown in  FIG. 1  is a widely used box type cabinet. However, the present disclosure may not be limited to the box type. The cabinet  101  may be formed by a front panel  109  forming a front surface, a rear panel  102  forming a rear surface, a base panel and a top panel forming a bottom surface and a top surface, and side panels forming both side surfaces. 
     The front panel  109  of the cabinet  101  may be provided with an inlet port for introducing clothes as a target to be dried into the drum  110 , so as to form a path connected to the drum  110 . The inlet port may be open or closed by the door  120  rotatably mounted onto the front panel  109 . A control panel (not shown) which includes various manipulation buttons and a display device may be provided above the inlet port. 
     The drum  110  may be rotatably installed within the cabinet  101  to dry the clothes therein. The drum  110  may be rotatably supported within the cabinet  101  by supporters (not shown) at front and rear sides thereof. The front side of the drum  110  may be open to be connected to the inlet port, and the rear side of the drum  110  may be closed by a drum back  111  which forms an inner surface of the drum  110 . Here, the front side of the drum  110  is open but a space for receiving the clothes may be entirely closed by the door  120 . The drum  110  may be rotatable with respect to the cabinet  101  but the drum back  111  may be fixed onto the cabinet  101 . 
     The drum  110  may have a cylindrical shape, and be connected to a driving motor  130 , which is disposed at a lower portion of the dryer, by a power transfer belt  132 , so as to receive a rotational force from the driving motor  130 . The driving motor  130  may have a pulley  131  at its one side, and the power transfer belt  132  may be connected to the pulley  131 . 
     The drum back  111  of the drum  110  may face the rear panel  102  of the cabinet  101 . Here, the rear panel  102  may have a protruding portion  103  which partially protrudes from the rear panel  102  to the outside based on a size or length of the drum  110 . Accordingly, the rear panel  102  may have a reinforced rigidity by virtue of the protruding portion  103 . 
     The drum  110  may receive heated air to be used for drying via an outlet port  112  formed on the drum back  111 . The heated air to be used for drying may be generated by heating external air in a heater assembly  210  of the module part  200  to be explained later. 
       FIG. 2  shows the module part  200  mounted in the cabinet  101  of the dryer and the link unit  300  for mounting the module part  200 . As shown in  FIG. 2 , the module part  200  may be connected to the rear of the cabinet  101 . Therefore, to supply heated air generated in the module part  200  at the rear of the cabinet  101  into the drum  110 , a through hole  104  may be formed through the rear panel  102 . Also, the cabinet  101  may be provided with a connecting duct  140  for communicating the drum  110  with the heater assembly  210  of the module part  200 . 
       FIGS. 3 and 4  show the connecting duct  140  in more detail. As shown in  FIG. 3 , the connecting duct  140  may be mounted onto the main body  110  to be connected to the drum back  111  via the rear panel  102 . The drum back  111  may also be provided with the outlet port  112 . However, the outlet port  112  may be shielded by a porous plate  142  disposed on the connecting duct  140 . The porous plate  142  may function to filter off foreign materials and the like. The connecting duct  140  is a component for smoothly connecting the main body  100  and the module part  200  to each other in view of a passage of air to be used for drying. 
     The connecting duct  140  may include a sealing unit  143  for allowing the heated air supplied by the heater assembly  210  to be supplied only into the drum  110  via the drum back  111 . The sealing unit  143  may be disposed on a border portion  141  of the connecting duct  140  on which the heater assembly  210  to be explained later contacts the connecting duct  140 . 
     The sealing unit  143  may include a sealing member  143   a  for sealing a circumference of a portion where the connecting duct  140  and the heater assembly  210  contact each other, and a sealing bead  143   b  disposed at the outside of the sealing member  143   a  for sealing a circumference of the connecting duct  140 . Also, the connecting duct  140  may include a receiving portion  143   c  for receiving the sealing member  143   a  therein. 
     The sealing member  143   a  may typically be made of ethylene propylene diene monomer (EPDM) synthetic rubber, for example. The sealing bead  143   b  is a component which is closely adhered onto one side of the receiving portion  143   c , in which the sealing member  143   a  is received, at the outside of the sealing member  143   a , thereby preventing the leakage of the heated air. Therefore, a part of the sealing bead  143   b  may be a partial surface of the receiving portion  143   c.    
     From the perspective of the configuration, air heated by the heater assembly of the module part may be supplied into the drum without a loss so as to increase a quantity of air used for drying a large quantity of clothes. Also, the module part may be connectable even to a random dryer. This may result in improvement of generality and usability of the dryer. In addition, the configuration of the dryer may prevent an introduction of external cold air which is not heated, avoiding degradation of drying efficiency. 
     Meanwhile, a filter  150  for filtering off foreign materials such as lint contained in the air discharged out of the drum  110  may be installed below the front of the drum  110 . Also, an exhaust duct  160  for exhausting the air, from which the foreign materials have been filtered off, out of the drum  110  may be installed. The exhaust duct  160  is named based on the point that the air is exhausted based on the drum. 
     The exhaust duct  160  may form a passage for transferring air within the drum  110  toward a blower assembly  250  to be explained later. A blower fan  261  which is disposed in the blower assembly  250  may generate a difference of pressure, and accordingly the exhaust duct  160  may suck the air contained within the drum  110 . 
     The blower assembly  250  may be coupled to the rear panel  102  located at the rear of the cabinet  101 . Hence, the exhaust duct  160  may extend from the front side toward the rear side of the drum  110  to be connected to the blower assembly  250  via the rear panel  102 . 
     Air to be used for drying within the main body  110  of the dryer may be heated through the heater assembly  210  and then supplied into the drum  110  of the main body  100  via the connecting duct  140 . The air after being used for drying in the drum  110  may be discharged to the outside via the exhaust duct  160  and the blower assembly  250 . 
     In the meanwhile, the module part  200  may include a heater assembly  210  and a blower assembly  250  as components connected to the rear of the main body  100 . Also, the module part  200  may include a housing  290 , and the heater assembly  210  and the blower assembly  250  may be disposed within the housing  290 . 
       FIG. 5  shows the housing  290  of the module part  200 . Referring to  FIG. 5 , the housing  290  of the module part  200  may include both side surfaces  291 , a rear surface  293 , a lower surface  292   b  and an upper surface  292   a . However, the housing  290  may not have a front surface because the module part  200  is coupled to the rear panel  102  of the main body  100 . 
     The housing  290  may also include at least one air inlet port  294  through which external air flows in.  FIG. 5  shows a plurality of air inlet ports  294  formed through the rear surface  293  of the housing  290  in form of a slit. 
     The housing  290  may also include an air outlet port  295  through which air discharged from the drum  110  is sucked via the blower assembly  250  and then discharged out of the module part  200 . An exhaust port of the blower assembly  250  may penetrate through or be connected to the air outlet port  295 . 
     Referring to  FIG. 1 , legs  296  for supporting the module part  200  with respect to the ground may be disposed on the lower surface  292   b  of the housing  290 . The legs  296  may have a predetermined height to allow the lower surface  292   b  to be spaced apart from the ground. The legs  296  may be coupled to the lower surface  292   b  by screws. The detailed configuration of the leg is already well known, so detailed description thereof will be omitted. 
     Referring to  FIG. 5 , the lower surface  292   b  and the upper surface  292   a  of the housing  290  may have the same shape as each other. That is, the lower surface  292   b  may be used as the upper surface  292   a  when being turned upside down. Accordingly, the same component may be used as both the upper and lower surfaces, thereby improving convenience in operation. Also, this may be efficiently used in a stacking structure of a plurality of dryers which will be explained later. 
       FIG. 6  shows the heater assembly  210 . Referring to  FIG. 6 , the heater assembly  210  may include a heater casing  231 ,  232 ,  233 ,  234  and  235 , a heater module  220  as a heating device disposed within the heater casing, and brackets  236  for mounting the heater module  220  in the heater casing. 
     The heater casing may include a front surface  231 , a rear surface  235 , both side surfaces  232 , a lower surface  234  and an upper surface  233 . The front surface  231  may be provided with a through hole  231   a  which is open such that heated air is supplied into the drum  110 . The through hole  231   a  of the heater casing may be connected to the connecting duct  140  of the main body  100 . The connecting duct  140  may be closely adhered onto the front surface  231  forming an outer side of the through hole  231   a , such that the sealing unit  143  of the connecting duct  140  can prevent the heated air from being externally discharged. 
     The heater module  220  may have a structure that a plurality of heating wires are connected to a heater frame. The heater module  220  may be fixed onto the side surfaces  232  of the heater casing by the brackets  236 . The brackets  236  may be fixed onto the heater casing by screws.  FIG. 6  exemplarily shows four brackets  236 , considering the weight of the heater module  220 . 
       FIG. 7  shows the bracket  236  in more detail, and  FIG. 8  shows the state that the heater module  220  is mounted onto the bracket  236 . Referring to  FIG. 7 , the bracket  236  may include a portion  236   a  coupled to the heater casing, and a portion  236   b  coupled to the heater module  220 . A frame of the heater module  220  may be mounted onto the portion  236   b  coupled to the heater module  220  such that the heater module  220  can be supported. 
     In  FIG. 7 , a plurality of mounting ribs  236   c  for assisting the heater module  220  to be mounted onto a uniform mounting position may be formed on the portion  236   b  coupled to the heater module  220 . The plurality of mounting ribs  236   c  may be spaced apart by uniform intervals so as to form mounting slots  236   d.    
     Referring to  FIG. 8 , heater frames  221  of the heater module  220  may be engaged with the mounting slots  236   d . Accordingly, the heater frames  221  may be located with the uniform intervals by the mounting ribs  236   c . This may result in facilitation of the mounting of the heater module  220  and improvement of operation efficiency and stability of the dryer. 
     In the meantime, external air may be supplied into the heater module  220  via the heater casing and then heated.  FIG. 6  shows at least one air inlet port  234   a  and  235   a  formed through the lower surface  234  and the rear surface  235 , respectively, for introduction of external air therethrough. Here, positions of the air inlet ports formed through the heater casing may not be limited to those shown in  FIG. 6 . 
     Referring to  FIG. 6 , the heater assembly  210  may further include a middle plate  237  for blocking radiant heat generated in the heater module  220  from being directly transferred to the drum  120 . The middle plate  237  may be located between the heater module  220  and the through hole  231   a  of the front surface  231 . Accordingly, the middle plate  237  may form a passage of the heated air. Consequently, the air heated by the heater module  220  may flow through the upper surface  233  of the heater casing and be supplied into the drum  120  through the through hole  231  a of the front surface  231 . 
     Referring to  FIG. 9 , the heater assembly  210  may include a first thermostat  240  disposed on the upper surface  233  of the heater casing as a position adjacent to an outlet side of the heater module  220  so as to turn the heater module  220  on or off according to air temperature. Also, the heater assembly  210  may further include a slit  241  located between the first thermostat  240  and the heater module  220  for allowing introduction of external air therethrough. 
       FIG. 10  shows the slit  241  in more detail. Referring to  FIG. 10 , the slit  241  may be formed through the upper surface  233  of the heater casing. Here, the slit  241  may be formed directly through the upper surface  233  because the upper surface  233  of the heater casing has an inclination. However, if the upper surface of the heater casing is not inclined, the slit  241  may be formed through the rear surface  235  of the heater casing adjacent to the first thermostat  240 . 
     In  FIG. 10 , the slit  241  may form a blocking flow A by external air. Accordingly, air B heated by the heater module  220  may be blocked from flowing to the first thermostat  240  due to the blocking flow A generated by external air introduced via the slit  241 . That is, a considerable amount of the heated air B may be blocked by the blocking flow A without directly contacting the first thermostat  240 . 
     The generation of the blocking flow A by the external air may result in an obvious difference of air temperature between a temperature of air when the external air flows through the slit  241  and a temperature of air when the external air does not flow through the slit. This may not require for an effort to decide an accurate mounting position of the first thermostat because the mounting position of the first thermostat is not an issue. Consequently, convenience in operation may be improved. 
     Also, since the periphery of the first thermostat  240  may be cooled by the blocking flow by the slit  241 , the first thermostat  240  may be installed to be more adjacent to the heater module  220 . This may improve spatial efficiency, thereby reducing the size of the dryer. 
     In addition, to prevent the first thermostat  240  from unnecessarily turning the heater module  220  off, the turn-off of the heater module  220  by the first thermostat  240  may be carried out only when external air is not smoothly introduced. This may result in improvement of efficiency of the dryer. That is, when external air is smoothly introduced into the heater casing through the housing  290 , the blocking flow A may also be formed by the slit, which may result in prevention of an unnecessary operation of the first thermostat. 
     Meanwhile, the heater assembly  210  may further include a passage guide  242  for guiding a flow path of external air which has flowed through the slit  241 . Referring to  FIG. 10 , the passage guide  242  may be formed beneath the upper surface  233  on which the slit  241  is formed, and extend toward the first thermostat  240  from the lower side of the slit  241 . 
     The passage guide  242  may forcibly form a passage for guiding external air to flow toward the first thermostat  240 . This may further improve the efficiency of the aforementioned blocking flow by the external air. 
       FIG. 11  shows the blower assembly  250 . Referring to  FIG. 11 , the blower assembly  250  may include a blower casing  270 , and a blower fan  261  and a fan motor  265  both disposed within the blower casing  270 , and an exhaust port  267 . 
     Air discharged from the drum  110  through the exhaust duct  160  may be discharged through the exhaust port  267  by the blower fan  261 . That is, the air flowed through the exhaust duct  160  may be introduced into the blower casing  270  via an inlet port  271  formed on a lower portion of the blower casing  270 . The introduced air may be sucked by the blower fan  261  to be transferred toward the exhaust port  267  via a fan housing  262 . 
     The fan motor  265  for driving the blower fan  261 , as shown in  FIG. 1 , may be connected to an outside of the blower casing  270 . The fan motor  265  may be provided, separate from the driving motor  130  of the main body  100 , so as to increase an amount of air to be supplied to the drum  110  by use of the blower fan  261 . 
       FIG. 12  shows a link unit  300  for connecting the main body  100  and the module part  200  to each other. Referring to  FIG. 12 , the link unit  300  may include a pair of support frames  310  for coupling the main body  100  and side surfaces of the module part  200  to each other, and a plurality of guide frames  320  for supporting the support frames  310  in a connected state. 
     The support frames  310  may be disposed in a perpendicular direction. One side surface of each support frame  310  may be coupled to a rear end portion of each side panel of the cabinet  101 . Also, another surface of each support frame  310  may be coupled to a front end portion of each of both side surfaces of the housing  290 . Accordingly, the rear panel  102  and the module part  200  may be coupled to each other by a predetermined interval therebetween. In addition, the module part  200  may be connected to the cabinet  101  regardless of a protruded level of the protruding portion  103  formed on the rear panel  102 . That is, the link unit  300  may connect the module part  200  to the cabinet  101  regardless of the shape of the rear panel  102 . Thus, the module part  200  may also be connected to a rear side of the main body  100 . 
     The guide frames  320  may be disposed in a horizontal direction, and provided in plurality for supporting the support frames  310  in the connected state. However, the guide frames  320  may not obscure a through hole  104  formed through the rear panel  102 . Also, as shown in  FIG. 13 , the guide frames  320  may be coupled to the protruding portion  103  of the rear panel  102  by screws  321 . The support frames  320  may thusly be supported more stably. 
     As the heater assembly and the blower assembly are disposed within the module part, separate from the main body, a large heater and a large blower fan may be employed regardless of the size of the main body of the dryer, allowing for drying of a large quantity of clothes in the dryer. In addition, the module part may be connectable to a random dryer, which may reduce the requirement for fabricating a separate cabinet of the dryer. This may result in improvement of generality and usability and reduction of fabricating costs. 
     The main body and the module part may be connected to each other not directly but via the link unit. This may reduce the probability that the rear panel located at the rear of the main body changes in shape. Accordingly, the module part may be mounted regardless of the shape of the rear panel. That is, even if a separate module part is connected to the dryer, the module part may not affect the rear portion of the cabinet of the dryer, thereby providing the dryer with structural stability. 
       FIG. 14  shows a duct support frame which may be additionally provided on the link unit. Referring to  FIG. 14 , the exhaust duct  160  may extend from the rear panel  102  toward the blower assembly  250 . 
     The main body  100  and the module part  200  may be coupled to each other partially with a gap therebetween due to the support frames  310  of the link unit  300 . Accordingly, the exhaust duct  160  may be connected to the main body  100  and the module part  200  without any structural supporting. Therefore, a duct support frame  330  for preventing damage on the exhaust duct  160  during an installation or operation of the dryer may be disposed on the link unit  300 . 
     The duct support frame  330  may support the exhaust duct  160  between the rear panel  102  and the blower assembly  250  of the module part  200 . In detail, the duct support frame  330  may have one end coupled to the rear panel  102  and the other side coupled to the blower casing  270  of the blower assembly  250 . Here, the duct support frame  330  may be located adjacent to the side surface of the exhaust duct  160 . The duct support frame  330  may be disposed only at one side surface of the exhaust duct  160  or at a periphery of the exhaust duct  160 . 
       FIG. 15  schematically shows an air flow that external air introduced into the dryer according to the one exemplary embodiment is supplied into the drum and then discharged. Referring to  FIG. 15 , external air may be introduced into the air inlet port  294 . The air flowed into the housing  290  via the air inlet port  294  may be introduced into the heater assembly  210  via the rear air inlet port  235   a  formed through the rear surface  235  of the heater casing and the lower air inlet  234   a  formed through the lower surface  234  of the heater casing. 
     The air introduced into the heater assembly  210  may then flow to a lower portion of the heater module  220  and heated in the heater module  220 . The hot air generated in the heater module  220  may be supplied into the drum  110  through the through hole  231   a  of the front surface via the upper surface  233  of the heater casing. 
     Air which has been discharged after being used for drying within the dryer may be transferred to the blower assembly  250  by the blower fan  261 . In detail, as aforementioned, the air discharged out of the drum  110  may be transferred to the blower assembly  250  through the exhaust duct  160  after flowing through the filter  150 . As described with reference to  FIG. 11 , air introduced into the lower inlet port  271  of the blower casing  270  may be discharged to the outside through the exhaust port  267 . 
     In accordance with another exemplary embodiment, a dryer may further include a bypass unit  280 .  FIG. 16  is a rear perspective view showing a dryer in accordance with the another exemplary embodiment,  FIG. 17  is an enlarged perspective view showing an air introduction portion of the heater assembly shown in  FIG. 16 , and  FIG. 18  is a sectional view taken along the line I-I of  FIG. 16 . 
     The bypass unit  280  may transfer a part of air discharged via an exhaust port  267  toward the heater assembly  210 . The bypass unit  280  may include a bypass duct  281 , first and second connectors  283  and  285 , and a distributing member  287 . 
     The bypass duct  281  is a tube with an inner diameter, and may have one end communicating with the exhaust port  267  and the other end communicating with the lower portion of the heater casing. The bypass duct  281  may extend from one side of the exhaust port  267  up to the side surface  232  of the heater casing. Also, the bypass duct  281  may be formed to be curved, as shown in  FIG. 16 . 
     The first connector  283  is a polyhedron with one surface inclined, and may be hollow. The first connector  283  may fix one end of the bypass duct  281  onto the exhaust port  267  to communicate with each other. In detail, a side surface of the first connector  283  may be connected to the exhaust port  267 , and an upper surface of the first connector  283  may be connected to the bypass duct  281 . A surface of the first connector  283  which faces a surface of the first connector  283  communicating with the exhaust port  267  may be inclined such that air transferred from the exhaust port  267  into the bypass duct  281  can be smoothly introduced into the bypass duct  281 . 
     The second connector  285  has a shape similar to a hexahedron whose inside is hollow. The second connector  285  may fix the other end of the bypass duct  281  onto a lower portion of the side surface  232  of the heater casing so as to communicate with the heater casing. The second connector  285  may have one side surface open to be fixed onto the side surface  232  of the heater casing, and the other side surface communicating with the bypass duct  281 . 
     The distributing member  287  may include a plurality of distribution plates  287   a  and  287   b . The plurality of distributing plates  287   a  and  287   b  may guide air introduced into the heater casing via the second connector  285  to be evenly distributed to the heater module  220 . Referring to  FIGS. 17 and 18 , each distributing plate  287   a  and  287   b  is a plate which has a predetermined width and also has a bent portion. Each of the distributing plates  287   a  and  287   b  may extend from the second connector  285  in a horizontal direction and then extend up to a lower portion of the heater module  220  in an inclined state. The distributing plates  287   a  and  287   b  may be disposed with being spaced from each other by uniform intervals, thereby dividing an open section of the second connector  285  into three uniform parts in up and down directions. Hence, air introduced into the heater casing via the second connector  285  may be distributed by the distributing plates  287   a  and  287   b  to be evenly introduced into the lower portion of the heater module  220 . Also, an edge of the distributing plates  287   a  and  287   b  in a lengthwise direction may face the rear surface  235  such that external air introduced via the rear air inlet port  235   a  can flow into the heater module  220  with being mixed with air introduced via the bypass duct  281 . 
     When the distributing member  287  is installed, the lower air inlet port  234   a  may not be formed on the lower surface  234  of the heater casing. Also, as aforementioned, the distributing member  287  may be fixed onto the second connector  285 , the heater casing, or the end portion of the bypass duct  281 . 
       FIG. 19  is a graph showing changes in temperature based on a time with respect to air, which is heated in the heater module  220  and then supplied into the drum  110 , in the dryer according to the one exemplary embodiment, namely, in the dryer without the bypass unit  280 , and  FIG. 20  is a graph showing changes in temperature based on a time with respect to air, which is heated in the heater module  220  and then supplied into the drum  110 , in the dryer according to the another exemplary embodiment, namely, in the dryer with the bypass unit  280 . 
     The X-axis of each graph shown in  FIGS. 19 and 20  indicates a time by a unit of second, and the Y-axis thereof indicates a temperature of air, which is transferred after being heated in the heater module  220 , by a unit of ° C. Referring to  FIG. 19 , when air used for drying in the drum  110  is all discharged from the blower assembly  250  via the exhaust port  267  without being recycled, namely, when only external air is heated in the heater module  220  to be supplied into the drum  110 , a time taken until the temperature of the heated air prior to being introduced into the drum  110  reaches 150° C. may exceed 2000 seconds. On the contrary, referring to  FIG. 20 , when the air used for drying in the drum  110  is partially recycled, that is, external air and air to be used for drying are both heated by the heater module  220  and then supplied into the drum  110 , a time taken until the temperature of the heated air prior to being introduced into the drum  110  reaches 150° C. may be about 200 seconds. 
     Therefore, the air which has been used for drying may be recycled, thereby reducing power consumed in the heater module  220  during a drying operation. Also, the heated air supplied into the drum  110  may reach a specific temperature within a relatively short time, thereby reducing a drying time. 
     Referring back to  FIG. 16 , the dryer according to the another exemplary embodiment may further include a second thermostat  268  and a temperature sensor (e.g., thermistor)  269  disposed on one side of the exhaust port  267 , if necessary. The second thermostat  268  may automatically power the heater module  220  off when the temperature within the exhaust port  267  is more than a predetermined temperature. The thermistor  269  may send the temperature of the exhaust port  267  to a control unit for controlling the dryer. 
     In the meantime, a dryer may be provided in plurality, if necessary, and the plurality of dryers may be stacked on each other.  FIG. 21  shows a stacked state of the plurality of dryers.  FIG. 21  shows two dryer main bodies  100   a  and  100   b  stacked in a perpendicular direction. However, this embodiment is merely illustrative, and two or more dryer main bodies may be stacked or arranged side by side. 
     When the dryers are stacked perpendicularly, the module parts  200  as well as the main bodies  100  have to be stacked perpendicularly. Therefore,  FIGS. 22 and 23  show a configuration for stacking the module parts. 
     Referring to  FIGS. 22 and 23 , in a state that a plurality of module parts are connected in the perpendicular direction, a lower surface  292   b  of a housing of an upper module part and an upper surface  292   a  of a housing of a lower module part may be coupled to each other by supporting bolts  299   a  and nuts  299   b  to maintain an interval therebetween. 
     As aforementioned, the upper surface and the lower surface of the housing are fabricated in the same shape. Therefore, through holes through which legs are inserted may be formed at the same positions. Instead of using the legs, supporting bolts may be inserted to couple the upper module part and the lower module part to each other with a spaced distance therebetween. 
     In  FIG. 22 , the supporting bolt  299   a  may be supported at an opposite side of the nut  299   b  by a leg bracket  299   c . Although not shown, this is equally applied to both the upper and lower module parts. 
     With this configuration, even when a plurality of dryers are used in a stacked state to have high spatial efficiency, the module parts may be mounted without use of a separate coupling member, resulting in improvement of generality and usability of the dryer. 
     The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present disclosure. The present teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments. 
     As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.