Patent Publication Number: US-11649154-B2

Title: Water dispenser and control method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation Application of U.S. patent application Ser. No. 15/641,483 filed Jul. 5, 2017, which claims priority under 35 U.S.C. § 119 to Korean Application No. 10-2016-0084444 filed on Jul. 4, 2016, whose entire disclosures are hereby incorporated by reference. 
    
    
     BACKGROUND 
     1. Field 
     A water dispenser and a control method for a water dispenser are provided. 
     2. Background 
     A water dispenser may be a device that supplies water and allows a user to take out as much water as desired. Water dispensers may be designed to supply water kept therein to an outside through a nozzle when a user operates a lever or a button. Such water dispensers may be designed to open a valve of a nozzle and supply water while a user operates a lever or a button and releases the lever or the button to check an amount of water filled in a cup or a container. 
     Water dispensers may be applied to various products in various fields, such as, e.g., a refrigerator and a water purifier. Water dispensers for refrigerators may be designed to automatically supply a predetermined amount of water when a user operates them. Water dispensers may supply not only just purified water, but also cold water and hot water. 
     When a flow rate of hot water supplied from a water dispenser that supplies hot water is not uniform, a large temperature change may occur in the hot water. When the flow rate is reduced, water may be overheated by a heater that heats water, and the heater may be damaged or the water may boil such that the hot water channel may be damaged or a safety accident may occur. 
     Korean Patent Application Publication No. 10-2012-0112060 discloses a hot water supplier that turns off a heater when the flow rate of water flowing inside is smaller than a minimum flow rate by sensing the flow rate of water supplied. However, according to this configuration of the related art, when the flow rate is unstable, the heater may turn off, so it may be impossible to obtained water at a desired temperature. 
     The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein: 
         FIG.  1    is a perspective view of a water dispenser according to the present disclosure; 
         FIG.  2    is a block diagram schematically showing flow paths of hot water in the water dispenser; 
         FIG.  3    is a perspective view of a hot water module of the water dispenser; 
         FIG.  4    is an exploded perspective view of the hot water module; 
         FIG.  5    is a flowchart sequentially illustrating a process of dispensing hot water from the water dispenser; 
         FIG.  6 A  and  FIG.  6 B  are graphs showing a change in water output temperature according to a change in flow rate; 
         FIG.  7    is a graph showing flow rate, output of the hot water module, and water output temperature of the water dispenser; 
         FIG.  8    is a flowchart sequentially illustrating another process of dispensing hot water from the water dispenser; 
         FIG.  9    is a front view of a refrigerator equipped with a water dispenser according to the present disclosure; and 
         FIG.  10    is a cross-sectional view of a refrigerator door equipped with the water dispenser. 
     
    
    
     DETAILED DESCRIPTION 
     For explanation without limiting the disclosure and referring to  FIG.  1   , a water dispenser  1  according to the present disclosure may be a water purifier. The water dispenser  1  may have an external shape formed by a case  10 . The case  10  may have rounded front and rear and flat top, bottom, and left and right sides. A filter that purifies water to be supplied, various valves including a hot water module  30  that heats the purified water, and various components to supply water may be provided in the case  10 . 
     An operation unit (e.g. a control panel or display)  110  may be formed on the top of the case  10 . The operation unit  100 , which may allow a user to operate the water dispenser  1 , may have a dispensing button  111  to dispense water. The operation unit  100  may further have a plurality of selection buttons  112  to select states of water to be dispensed from the water dispenser  1 , for example, hot water, cold water, and purified water. A display that displays operation or setting states of the water dispenser  1  may be further provided. 
     A faucet  120  may be formed on the front of the case  10 . The faucet  120  may be provided at a predetermined height from the bottom of the case  10  and may have a nozzle  121  that extends downward so that water may be supplied into a container under the nozzle  121 . 
     A tray  130  may be provided under the faucet  120 . The tray  130  may be provided under the faucet  120  to support a container and collect water that drops and overflows when water is dispensed. The tray  130  may be detachably coupled to the case  10 . The tray  130  and the faucet  120  may turn together or independently on the case  10 . 
     Referring to  FIG.  2   , a supply pipe  21  connected to an external water source may be connected to the water dispenser  1 , and water supplied through the supply pipe  21  may be discharged to the faucet  120  after being purified and heated. The water dispenser  1  may be supplied with raw water through the supply pipe  21  connected to the external water source. The supply pipe  21  may extend inside the case  10  and may be connected to the hot water module  30  to produce hot water. 
     A flow sensor  211  and a control valve  212  may be provided along the supply pipe  21  inside the case  10 . The flow sensor  211  may sense or measure a flow rate of water supplied through the supply pipe  21 . The control valve  212 , which may have a structure capable of adjusting an opening ratio, may control the flow rate of water supplied through the supply pipe  21 . 
     When too much water passes through a hot water tank  41  of the hot water module  30 , the water may not be efficiently heated through the hot water tank  41  due to its high speed, so a temperature condition for the hot water may not be satisfied under this circumstance. Therefore, it may be possible to maintain an amount of water passing through the hot water tank  41  at a predetermined level using the control valve  212  so that hot water may always be dispensed at a predetermined temperature. The flow sensor  211  and the control valve  212  may be integrated. 
     Water may be supplied to the hot water module  30  through the supply pipe  21 , and the water heated through the hot water module  30  may be sent to the nozzle  121  through a discharge pipe  22 . A temperature sensor  221  to sense the temperature of water to be dispensed may be provided on the discharge pipe  22 . The temperature of the water to be dispensed may be measured by the temperature sensor  221 . The discharge valve  222 , which may be opened/closed to discharge hot water, may be provided on the discharge pipe  22 . 
     An exit path of the hot water module  30  may diverge and may be further connected to a vapor pipe  23 . The vapor pipe  23  may be provided to discharge vapor, which may be produced when the water in the hot water tank  41  boils, to the outside. A safety valve  231  may be provided on the vapor pipe  231 , so when a predetermined pressure over a set or prescribed pressure is generated, the safety valve  231  may open and discharge vapor to the outside. 
     The safety valve  231  may be provided to discharge vapor produced when hot water is heated in the hot water tank  41 , and may prevent the internal pressure of the hot water tank  41  from being excessively increased by vapor. The safety valve  231  may open at a predetermined pressure and may have various structures that may smoothly discharge vapor from the hot water tank  41 . An exit path from the safety valve  231  may be a drain pipe that extends out from the case  10 . 
     Output of the hot water module  30  may be controlled by a controller  50 . The controller  50  may control an output of the hot water module  30  based on the flow rate sensed by the flow sensor  211  or the water output temperature sensed by the temperature sensor  221 , so that water flowing inside may be heated and dispensed at a predetermined temperature. 
     Referring to  FIG.  3    and  FIG.  4   , the hot water module  30  may include an induction heating assembly or induction heater  40  configured to produce hot water and the controller  50  configured to control operation of the induction heating assembly  40 . The induction heating assembly  40  and the controller  50  may be combined in one module and provided as a module in the case  10 . The induction heating assembly  40 , which may be provided to heat purified water supplied through the supply pipe  21  into hot water, may heat water using an induction heating principle. 
     The induction heating assembly  40  may include a hot water tank  41  through which water (which may be purified prior to entering the hot water tank  41 ) may pass, a working coil  42  to heat the water passing through the hot water tank  41 , and a mounting bracket  43  on which the working coil  42  and the hot water tank  41  may be mounted. The mounting bracket  43  may provide a space to receive the hot water tank  41 , the working coil  42 , and ferrite cores  44 . The mounting bracket  43  may be made of resin that may not be deformed or damaged even at high temperature. 
     A bracket coupling portion or bracket coupler  431  that couples to the controller  50  may be formed at a corner of the mounting bracket  43 . A plurality of bracket coupling portions  431  may be provided and ends of the bracket coupling portion  431  may be formed or extend in different shapes and directions. Accordingly, the induction heating assembly  40  may be fitted to the controller  50  and may be mounted at a set or prescribed position. 
     A bracket mount  432  to mount a sensor bracket  45  may be formed at a center of a side of the mounting bracket  43  on which the hot water tank  42  may be mounted. A tank temperature sensor  451  and a fuse  452  may be mounted at a center of the bracket mount  432 . 
     The tank temperature sensor  451  to measure the temperature of the hot water tank  41  may be provided at a center of the sensor bracket  45 . The tank temperature sensor  451  may measure the temperature at the center of the hot water tank  41  to determine the temperature of hot water without directly measuring the temperature of the hot water in the hot water tank  41 . The tank temperature sensor  451  may maintain the temperature of hot water within an appropriate range. It may be possible to determine whether to further heat or stop heating hot water on the basis of the temperature sensed by the tank temperature sensor  451 . 
     The fuse  452  may be mounted on the sensor bracket  45 . The fuse  452  may cut power for the induction heating assembly when the water in the hot water tank  41  is excessively overheated. 
     A plurality of coil fixing portions or coil mounts  453  may be formed around the sensor bracket  45 . The coil fixing portions  453  may extend outward from an outer side of the sensor bracket  45  to fix the working coil  42  on the mounting bracket  43 . Two coil fixing portions  453  may be provided at each of the upper and lower portions of the sensor bracket  45  and may orthogonally extend from corners of the sensor bracket  45  so as to fix the working coil  42 . 
     The working coil  42  may be provided on a front of the mounting bracket  43 . The working coil  42  may form magnetic flux to generate heat in the hot water tank  41 . When a current is supplied to the working coil  42 , the working coil  42  may form a magnetic flux, and the hot water tank  41  may generate heat via the magnetic flux. The working coil  42  may be provided on the front of the mounting bracket  43  and may face a flat side of both sides of the hot water tank  41 . The working coil  42  may be composed of several copper or other conductive wires, and the wires may be insulated. The working coil  42  may form a magnetic field or magnetic flux when a current is supplied to the working coil  42 . 
     The front side (which may face the working coil  42 ) of the hot water tank  41  may be influenced by the magnetic flux formed by the working coil  42 , whereby heat may be generated. A contour of the working coil  42  is shown, but wires of the working coil  42  may be wound around the bracket mount  432 . 
     The ferrite cores  44  may be provided on the front of the working coil  42 . The ferrite cores  44  may be provided to suppress a loss of current and may shield against magnetic flux. The working coil  42  may include a plurality of ferrite cores  44 , and the ferrite cores  44  may be circumferentially arranged around a center of the working coil  42 . The ferrite cores  44  may be fixed to core fixing portions or core mounts  433  of the mounting bracket  43 . The ferrite cores  44  may be attached or fitted to the core fixing portions  433 . The core fixing portions  433  may be circumferentially arranged similar to the ferrite cores  44 . 
     Snaps  434  that may lock and fix edges of the hot water tank  41  mounted on the mounting bracket  43  may be formed around the mounting bracket  43 . Accordingly, the working coil  42 , the ferrite cores  44 , the sensor bracket  45 , and the hot water tank  41  may be combined with the mounting bracket  43  as a module. 
     The hot water tank  41  may be mounted on the front of the mounting bracket  43 . The hot water in the hot water tank  41  may be heated via the magnetic flux formed by the working coil  42 . Accordingly, water may be heated into hot water by the hot water tank  41 . A shape of the hot water  41  may be flat and compact. The hot water tank  41  may have a shape corresponding to a shape of the induction heating assembly  40  to be able to be effectively heated when the induction heating assembly  40  is operated. 
     For example, the hot water tank  41  may be formed by bonding edges of a first tank panel or cover  411  having a flat plate shape and a second tank panel or cover  412  having a plate shape and recessed to form a channel or a storage space. An outlet pipe  414  that discharges heated water may be formed at a top of the hot water tank  41 , and an inlet pipe  413  that supplies heated water may be formed at a bottom of the hot water tank  41 . The hot water tank  41  may be instantaneously heated by induced electromotive force formed by the working coil  42  while water flows inside through the channel or the storage space from the inlet pipe  413  and is then discharged through the outlet pipe  414 , whereby hot water may be discharged. 
     A side of the first tank panel  411  that faces the working coil  42  may be flat and close to the working coil  42 , so an entire surface of the first tank panel  411  may be uniformly heated by an induced magnetic force generated by the working coil  42 . A plurality of foamed spacers or pillars  412   a  may be formed at or on the second tank panel  412 . The foamed spacers  412   a  may be recessed toward the first tank panel  311 , so they may contact with an inner side of the first tank panel  411  when the first tank panel  411  and the second tank panel  412  are combined such that the channel or storage space may be maintained between the first tank panel  411  and the second tank panel  412 . Accordingly, a space through which water may flow may be defined between the first tank panel  411  and the second tank panel  412  by the foamed spacers  412   a . The foamed spacers  412   a  may be made from a material different from foam, and further, shapes other than shown in the figures may be used. 
     The plurality of foamed spacers  412   a  may be formed close to the inlet pipe  413  and the outlet pipe  414  and may be spaced from each other in a width direction of the hot water tank  41 . The water in the hot water tank  41  may flow throughout an internal area of the hot water tank  41 , so the water can be effectively heated by the working coil  42 . The water flowing through the hot water tank  41  may be spread thin and wide so as to be quickly heated at a predetermined temperature by the working coil  42 . 
     The controller  50  may be provided behind the induction heating assembly  40 . The controller  50  may be connected with several valves and electronic devices including the induction heating assembly  40 , the flow sensor  211 , the control valve  212 , the temperature sensor  221 , and the discharge valve  222 . The controller  50  may be composed of a plurality of parts to control the induction heating assembly  40  and other components. 
     The controller  50  may include a control PCB  51 , a control case  52 , and a control cover  53 . The control PCB  51 , which may be provided to control the induction heating assembly  40 , may be mounted on the control case  52 . The control PCB  51  may control valves connected to the induction heating assembly  40 . The control case  52  may contain the control PCB  51  therein and may have an open side covered with the control cover  53 . The control PCB  51  may be housed between the control case  52  and the control cover  53  combined with each other. 
     A shield plate  54  may be provided on the front of the control cover  53 . The shield plate  54 , which may be provided to prevent magnetic flux from transferring to the control PCB  51  when the induction heating assembly  40  is operated, may be provided throughout the entire front of the control cover  53 . The shield plate  54  may be formed as a separate sheet and provided on the front of the control cover  53 . 
     Referring to  FIG.  5   , a user may place a container under the nozzle  1212  and then operate the dispensing button  111  of the operation unit  110  to take hot water from the water dispenser  1 . As the dispensing button  111  is operated, the discharge valve  222  may open and water may start to be supplied to the hot water tank  41  through the control valve  212  (S 110 ). 
     When water starts to be supplied to the hot water tank  41 , the flow sensor  211  may sense the flow rate of the water supplied. The flow rate of the water flowing into the hot water tank  41  may be controlled based on the opening ratio of the control valve  212 . Accordingly, the water supplied to the hot water tank  41  may maintain a predetermined flow rate and the output of the induction heating assembly  40  or the working coil  42  may also be maintained at a predetermined level so that hot water may be uniformly supplied at a predetermined temperature. 
     However, the flow rate of the water supplied through the supply pipe  21  may be rapidly reduced due to external factors when water is being dispensed from the water dispenser  1 . For example, when a large amount of water is used by an appliance, such as, e.g., a washing machine or a dishwasher in a bathroom or a kitchen while or immediately before water is supplied to the water dispenser  1 , the flow rate of the water that is supplied to the water dispenser  1  may be rapidly reduced. When such simultaneous use of water frequently occurs, the temperature of hot water that is dispensed may not be maintained at a predetermined level. 
     Referring to  FIG.  6 A , when the flow rate of water supplied to the hot water tank  41  is reduced by 20% from a target flow rate (about 0.4 LPM) with the working coil  42  operating with output of 2,550 W to supply hot water, the temperature of the dispensed water may be about 90.3° C. The temperature may be slightly higher than a target water output temperature, but an amount of produced steam may be minimal. 
     Referring to  FIG.  6 B , when the flow rate of water supplied to the hot water tank  41  is reduced by 30% from a target flow rate (about 0.356 LPM) with the working coil  42  operating with output of 2,550 W to supply hot water, the temperature of the dispensed water is about 94.2° C. The temperature may be higher than the target water output temperature and steam may be produced, so if water is supplied at a flow rate lower than the flow rate, water at a higher temperature may be dispensed and a large amount of steam may be produced, which may deteriorate durability and safety for the user. 
     In order to prevent damage to components of the water dispenser  1  and dispense hot water more safely by maintaining the water output temperature at a predetermined level, an exact flow rate of the water may be sensed that flows into the hot water tank  41  (S 120 ). Referring to  FIG.  6 B , when the flow rate of water supplied is reduced over about 30% from a set or prescribed flow rate, dispensing hot water may be dangerous due to too much steam and an excessive increase in temperature of the hot water. 
     Accordingly, when a water input flow rate is lower than the set flow rate, it may be possible to control the output of the working coil  42  through the controller  50 . In detail, the set flow rate may be set 30% smaller than the target flow rate that is supposed to be supplied through the supply pipe  21 . The set flow rate may be adjusted, if necessary, but it may be set 30% smaller than the target flow rate to prevent steam from being produced due to an excessive increase of the water output temperature. 
     The controller  50  may compare the current flow rate inputted from the flow sensor  211  with the set flow rate (S 130 ). Accordingly, when the water input flow rate is lower than the set flow rate, the controller  50  may reduce the output of the working coil  42 . The output of the working coil  41  to be reduced may be determined to correspond to the reduced ratio of flow rate. When the water input flow rate is very reduced, the output of the working coil  42  may be adjusted lower. 
     When the output of the working coil  42  is reduced, the temperature of the hot water heated in the hot water tank  41  may be decreased in proportion to the output, and as a result, the temperature of water dispensed may be maintained at a final target temperature (S 141 ). When the water input flow rate is larger than the set flow rate or equal to the target flow rate, the working coil  42  may operate at set output. Accordingly, the temperature of water dispensed may be maintained at an initial target temperature or within a target temperature range (S 142 ). 
     Therefore, hot water may be dispensed at a predetermined temperature, for example, the target temperature, through the nozzle  121  even while the flow rate of water supplied is changed. The flow sensor  211  may determine whether a target output flow rate set by a user has been reached. 
     If the controller  50  determines that the target output flow rate has not been reached, water may keep being supplied to the hot water tank  41  until the target output flow rate is reached, and the controller  50  may keep monitoring a change in water input flow rate and adjust the output of the working coil  42  in accordance with a change in water input flow rate, thereby heating the water flowing through the hot water tank  41  (S 150 ). When the controller  50  determines that the target output flow rate has been reached, the hot water module  30  and the working coil  42  may stop operating, the discharge valve  222  may close, and the operation of dispensing hot water may be finished (S 160 ). 
     Referring to  FIG.  7   , water may be supplied at a target flow rate in a normal water output period D 1 , and accordingly, the water passing through the hot water tank  41  may be heated at a set or prescribed output by the working coil  42 . Since the water input flow rate is not much changed, the output of the working coil  42  may also be maintained without a large change. The temperature of water dispensed may be maintained at 85° C.˜9° C. 
     The water input flow rate may be reduced under a set or prescribed flow rate while hot water is dispensed in a flow rate change period D 2 , in which the controller  50  may reduce the output of the working coil  42  when the water input flow rate decreases under the set flow rate. Accordingly, the temperature of the water dispensed may be maintained under about 90° C. without rapidly increasing even though the flow rate may rapidly decrease. The change of flow rate and adjustment of output of the working coil  42  may occur several times during one dispensing period, and it may take more time to reach a target water output flow rate due to the reduction in flow rate. 
     Another embodiment of the present disclosure may be characterized by controlling the output of the working coil, depending on a change in a water output temperature, by measuring a water output temperature through the controller so that hot water may be dispensed at a predetermined temperature. 
     A water dispenser according to such another embodiment of the present disclosure may have the same configuration as the embodiment described above, but may be different in terms of a control method, so same components may be given same reference numerals and may not be described in detail. 
     Referring to  FIG.  8   , a user may place a container under the nozzle  1212  and then operate the dispensing button  111  of the operation unit  110  to dispense hot water from the water dispenser  1 . As the dispensing button  111  is operated, the discharge valve  222  may open, and water may start to be supplied to the hot water tank  41  through the control valve  212  (S 210 ). 
     When water starts to be supplied to the hot water tank  41 , the temperature sensor  221  may sense the temperature of the water discharged through the discharge pipe  22 . The flow rate of water flowing into the hot water tank  41  may be maintained at a predetermined level based on the opening ratio of the control valve  212 , the output of the induction heating assembly  40 , that is, the working coil  42  may also be maintained at a predetermined level, and hot water may be uniformly provided at a predetermined temperature. 
     However, the flow rate of the water supplied through the supply pipe  21  may be rapidly reduced due to external factors when water is being dispensed from the water dispenser  1 . When the flow rate is rapidly reduced, the water output temperature may be rapidly increased, and a large amount of vapor may be produced and deteriorate durability of the product and safety for the user. In order to prevent damage to the components in the water dispenser  1  and dispense hot water more safely by maintaining the water output temperature at a predetermined level, the water output temperature may be measured by the temperature sensor  221  (S 220 ). 
     When the water output temperature is lower than a set or prescribed temperature, the controller  50  may control the output of the working coil  42 . For example, the set temperature may be set higher by a predetermined level than a target water output temperature. The set temperature may be adjusted, if necessary, but it may be set 5° C.˜10° C. higher than the target temperature to prevent steam from being produced due to an excessive increase of the water output temperature. 
     The controller  50  may compare the current flow rate that is inputted from the temperature sensor  221  with the set flow rate (S 230 ). When the water output temperature is higher than the set temperature, the controller  50  may reduce the output of the working coil  42 . The output of the working coil  41  to be reduced may be determined to correspond to the increased ratio of temperature. Accordingly, the output of the working coil  42  may be adjusted lower when the water output temperature is relatively much higher than the target temperature 
     When the output of the working coil  42  is reduced, the temperature of the hot water heated in the hot water tank  41  may be decreased in proportion to the output, and as a result, the temperature of water dispensed may be maintained at the final target temperature (S 241 ). 
     When the water output temperature is the same as the target temperature or is within a predetermined target temperature range, the working coil  42  may operate at a set output. Accordingly, the temperature of water dispensed may be maintained at the initial target temperature or within the target temperature range (S 242 ). Therefore, hot water may be dispensed at a predetermined temperature, that is, the target temperature through the nozzle  121 , even while the flow rate of water supplied may be changed. 
     The flow sensor  211  may determine whether a target output flow rate set by a user has been reached. If the controller  50  determines that the target output flow rate has not been reached, water may keep being supplied to the hot water tank  41  until the target output flow rate is reached, and the controller  50  may keep monitoring a change in water output temperature and adjust the output of the working coil  42  in accordance with a change in water input flow rate, thereby heating the water flowing through the hot water tank  41  (S 250 ). 
     When the controller  50  determines that the target output flow rate has been reached, the hot water module  30 , that is, the working coil  42 , may stop operating, the discharge valve  222  may close, and operation of dispensing hot water may be finished (S 260 ). 
     A water dispenser according to another embodiment of the present disclosure may be mounted on the door of a refrigerator to dispense water or ice, other than a water purifier. Such an embodiment of the present disclosure may have the same hot water module and internal configuration thereof except for a structure of the case for mounting the water dispenser. 
     Referring to  FIG.  9    and  FIG.  10   , a water dispenser  80  according to another embodiment of the present disclosure may be mounted on a refrigerator. A refrigerator  2  may have an external shape formed by a cabinet  60  having a storage space and doors  71  and  72  for opening/closing of the front of the cabinet  60 . The storage space may be divided into a refrigerator compartment and a freezer compartment, and these compartments may be opened/closed by a refrigerator door  71  and a freezer door  72 , respectively. 
     The water dispenser  80  may be provided on a front of the refrigerator door  71 . The water dispenser  80  may be provided for a user to get water from the refrigerator  2 . An ice maker compartment  90 , which may be an independent insulating space and opened/closed by an ice maker compartment door  901 , may be formed in the refrigerator door  71 . An ice maker  91  and an ice bank or container  92  that makes and holds ice may be provided in the ice maker compartment  901 . The ice bank  92  may be connected to the water dispenser  80  so that ice may be dispensed out through the water dispenser  80 . 
     The water dispenser  80  may include a dispenser case  81  mounted on the front of the refrigerator door  71  to provide a recessed space. The dispenser case  81  may provide a space in which a container for taking or dispensing water or ice may be put. An operation member (e.g., a lever or button)  82  to dispense water or ice may be provided on the inner side of the dispenser case  81 , and a nozzle  83  may be provided over the operation member  82 . 
     An operation unit (e.g., display or control panel)  84  may be provided over the case  81  for a user to be able to select various operations, such as, e.g., setting the kind, temperature, and amount of water to be dispensed from the water dispenser  80 . It may be possible to output or display the operational state of the refrigerator  2  and an operation state set by the user through the operation unit  84 . 
     The refrigerator door  71  may include an outer plate  701  forming the external shape of the front of the refrigerator door  71 , a door liner  702  forming the shape of the rear of the refrigerator door  71 , and an insulator  703  provided between the outer plate  701  and the door liner  702  to prevent heat exchange. The dispenser case  81  may be mounted on the outer plate  701 . 
     A hot water module  30  may be provided behind the dispenser case  81  and may be received in a module case  31  behind the dispenser case  81 . The module case  31  may be covered with or by the insulator  703  except for a surface in contact with the dispenser case  81 , so heat generated by the hot water module  30  may not transfer into the refrigerator  2 . 
     A cold water tank  710  that supplies cold water to the water dispenser  80  may be provided on a rear of the door liner  702  at a position corresponding to the hot water module  30  to prevent the heat from the hot water module  30  from transferring into the refrigerator. 
     The structure of the hot water module  30  of the water dispenser  80  having this structure may be the same as those in the previous embodiments, and the output of the hot water module may be controlled based on a change in flow rate of water supplied or a water output temperature. Therefore, it may be possible to maintain the water output temperature at a predetermined level even if the water input flow rate may be rapidly decreased while hot water is dispensed. 
     Embodiments disclosed herein may provide a water dispenser that may supply hot water at a predetermined temperature regardless of a supply flow rate, and a method of controlling the water dispenser. Embodiments disclosed herein may also provide a water dispenser that may supply hot water at a predetermined temperature by controlling an output of an induction heating type of hot water module based on reduction of a supply flow rate or a water output temperature. 
     According to embodiments disclosed herein, a water dispenser may include an induction heating assembly that heats water that is supplied; a supply pipe that supplies water to the induction heating assembly; a flow sensor that is provided on the supply pipe and senses an amount of water that is supplied to the induction heating assembly; and a controller that reduces output of the induction heating assembly when a flow rate of water sensed by the flow sensor is a set flow rate or less. 
     According to embodiments disclosed herein, a water dispenser may includes an induction heating assembly or induction heater that heats water that is supplied; a discharge pipe that discharges water heated by the induction heating assembly; a temperature sensor that is provided on the discharge pipe and senses a temperature of hot water that is discharged; and a controller that reduces output of the induction heating assembly when a temperature of hot water sensed by the temperature sensor is a set temperature or higher. 
     The induction heating assembly may include a hot water tank through which purified water passes; a working coil that is wound several times at a position facing the hot water tank and generates an electromagnetic force to heat the water of the hot water tank via induction heating; a plurality of ferrite cores that is circumferentially arranged around a center of the working coil to prevent a loss of the electromagnetic force generated by the working coil; and a mounting bracket on which the hot water tank, the working coil, and the ferrite cores are mounted. 
     The controller may be provided on a rear of the induction heating assembly and coupled to a rear of the mounting bracket. A safety valve that discharges vapor in the hot water tank may be provided at an exit of the hot water tank. A control valve that controls the flow rate of water that flows into the hot water tank may be provided at an inlet of the hot water tank. 
     The hot water tank may include a first cover that forms a side facing the working coil and has a flat shape and a second cover that is bonded to an edge of the first cover with a gap therebetween to form a space through which water flows. A plurality of foamed portions or spacers recessed toward the first cover to be in contact with the first cover may be formed at the second cover. 
     The controller may reduce the output of the induction heating assembly in proportion to a decrease of the water input flow rate or an increase in water output temperature. A control valve to control the flow rate of water that is supplied may be provided on the supply pipe and integrated with the flow sensor. 
     According to embodiments disclosed herein, a method of controlling a water dispenser having a discharge valve that may be opened by a user to dispense water, an induction heating assembly that heats and then discharges water that is supplied, and a controller that controls output of the induction heating assembly, the method including measuring a change in the flow rate of water supplied using the flow rate sensor; and dispensing water through the discharge valve, wherein a temperature of the water that is dispensed is maintained at a predetermined level based on a change in flow rate of the water that is supplied. 
     The controller may compare the flow rate of water that is supplied to the induction heating assembly with a set flow rate through a flow sensor, maintain the output of the induction heating assembly when the supplied flow rate is the set flow rate or more, and reduce the output of the induction heating assembly when the supplied flow rate is the set flow rate or less. The set flow rate may be set 20%-30% lower than a target flow rate. The output of the induction heating assembly may be reduced in proportion to a reduced ratio of the supplied flow rate. 
     The controller may compare the temperature of water that is discharged from the induction heating assembly with a set temperature through a temperature sensor, maintain the output of the induction heating assembly when the temperature of the water that is discharged is the set temperature or lower, and reduce the output of the induction heating assembly when the temperature of the water that is discharged is the set temperature or higher. The set temperature may be set 5° C.˜10° C. lower than a target temperature. The output of the induction heating assembly may be reduced in proportion to an increased ratio of the temperature of the water that is discharged. 
     Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.