Patent Description:
Details in the background section do not constitute the related art but are given only as background information concerning the subject matter of the present invention.

A dishwasher is an electric appliance that washes dishes and cooking utensils stored inside by spraying wash water. At this time, the wash water used in the washing may include a washing detergent.

A conventional dishwasher may include a tub defining a washing space, a storage part accommodating washing targets inside the tub, a spray arm spraying wash water to the storage part, and a sump storing wash water and supplying the wash water to the spray arm.

By using the dishwasher, it is possible to reduce the time and effort required for washing dishes after eating, thereby contributing to user convenience.

When the dishwasher is used to wash dishes, wash water may be heated and used in order to increase a washing effect. An electric heater may be used as a heating device for heating wash water. Meanwhile, as another method, wash water may be heated by a heat pump apparatus instead of the electric heater.

The heat pump apparatus has high energy efficiency, compared with the electric heater. Accordingly, when wash water is heated by using the heat pump apparatus, electricity consumption can be reduced.

<CIT> cited as the background art discloses a dishwasher that has a structure including a heat pump to heat wash water.

A case in which heat is supplied to a tub in the dishwasher is when a washing mode and a drying mode area performed. In the washing mode, wash water is heated and sprayed to the tub to increase washing efficiency for dishes. In the drying mode for drying the washed dishes, heated air is supplied to the tub to increase drying efficiency for the dishes accommodated inside the tub.

A heat pump apparatus is configured to heat wash water in the washing mode and heat air supplied to the tub in the drying mode. Water and air have different specific heats. Since it has a lower specific heat than water, air can reach the same high temperature as water by receiving a relatively small amount of heat, compared to water.

Accordingly, the amount of heat supplied to wash water in the washing mode and the amount of heat supplied to air in the drying mode need not be the same. When a heat pump supplies the same amount of heat to wash water in the washing mode and air in the drying mode, energy efficiency could be deteriorated.

Accordingly, the heat pump apparatus needs to be designed to supply an optimal amount of heat in the washing mode supplying a relatively large amount of heat and an optimal amount of heat in the drying mode supplying a relatively small amount of heat.

<CIT> discloses a washing electric appliance.

One objective of the present invention is to provide a dishwasher having an improved energy efficiency structure that may heat wash water and air by using a heat pump apparatus, compared to an electric heater.

A further objective of the present invention is to provide a dishwasher including a heat pump apparatus with a structure of heating both wash water and air, which are supplied to a tub.

A still further objective of the present invention is to provide a dishwasher including a heat pump apparatus designed to supply an optimal amount of heat in a washing mode supplying a relatively large amount of heat and an optimal amount of heat in a drying mode supplying a relatively small amount of heat.

A still further objective of the present invention is to provide a dishwasher including a heat pump apparatus that has a structure of increasing the number of evaporators as the size of required heat increases.

The present invention is defined by independent claim <NUM>; the dependent claims describe embodiments of the invention.

Aspects according to the present invention are not limited to the above ones, and other aspects and advantages that are not mentioned above can be clearly understood from the following description and can be more clearly understood from the embodiments set forth herein.

A dishwasher according to an embodiment may include a heat pump apparatus. The heat pump apparatus is provided to have a coefficient of performance (COP) exceeding <NUM>. Accordingly, the heat pump apparatus provided in the dishwasher according to the embodiment may have increased energy efficiency in heating wash water and air, compared to the conventional dishwasher heating wash water by using the electric heater.

The heat pump apparatus includes a compressor configured to compress refrigerant; a first heat exchanger to which refrigerant is introduced from the compressor, the first heat exchanger configured to heat water introduced into the tub; a first expansion valve to which refrigerant is introduced from the first heat exchanger, the first expansion valve configured to expand refrigerant; a second heat exchanger to which refrigerant is introduced from the first expansion valve; a second expansion valve disposed in parallel with the first expansion valve, the second expansion valve to which refrigerant is introduced from the first heat exchanger; and a third heat exchanger disposed in parallel with the second heat exchanger, the third heat exchanger to which refrigerant is introduced from the second expansion valve when the dishwasher performs a washing mode.

Based on an operational mode of the dishwasher, the role of the first heat exchanger to the third heat exchanger may be changed to a condenser or an evaporator. When the dishwasher performs a washing mode, the heat pump apparatus may heat wash water. When the dishwasher performs a washing mode, the heat pump apparatus may heat wash water and when it performs a drying mode, the heat pump apparatus may heat air. Accordingly, the heat pump apparatus may heat both wash water and air.

When the dishwasher performs the washing mode, the first heat exchanger may be operated as a condenser and the second heat exchanger and the third heat exchanger may be operated as an evaporator, thereby effectively heating water having a relatively high specific heat.

When the dishwasher performs the drying mode, the first heat exchanger may not be used, the second heat exchanger may be operated as the evaporator and the third heat exchanger may be operated as the condenser. Accordingly, a smaller amount of heat than the amount of the amount of heat supplied to water in the washing mode may be supplied to air having a relatively low specific heat, thereby effectively heating the air. The supply of excessive heat can be suppressed, thereby improving the energy efficiency of the heat pump apparatus.

The heat pump apparatus may include a four way valve connected with the compressor, the first heat exchanger, the second heat exchanger and the third heat exchanger and configured to change a flow path of a refrigerant.

The role of the first heat exchanger to the third heat exchanger may be variable by the four way valve changing the flow path of refrigerant. Based on the operation of the four way valve, two evaporators may be used in the washing mode requiring a relatively large heat supply amount and one evaporator may be used in the drying mode requiring a relatively small heat supply amount.

A dishwasher according to the present invention includes a heat pump apparatus, a tub defining a washing space and accommodating dishes; and a heat pump apparatus configured to heat wash water introduced into the tub,.

The heat pump apparatus includes a compressor configured to compress refrigerant; a first heat exchanger to which refrigerant is introduced from the compressor, the first heat exchanger configured to heat water introduced into the tub; a first expansion valve to which refrigerant is introduced from the first heat exchanger, the first expansion valve configured to expand refrigerant; a second heat exchanger to which refrigerant is introduced from the first expansion valve; a second expansion valve disposed in parallel with the first expansion valve, the second expansion valve to which refrigerant is introduced from the first heat exchanger; a third heat exchanger disposed in parallel with the second heat exchanger, the third heat exchanger to which refrigerant is introduced from the second expansion valve; and a four way valve connected with the compressor, the first heat exchanger, the second heat exchanger and the third heat exchanger and configured to change a flow path of a refrigerant.

The heat pump apparatus may include a first pipe connecting the four way valve and the compressor with each other; a second pipe connecting the four way valve and the first heat exchanger with each other; a third pipe connecting the four way valve and the second heat exchanger with each other; a fourth pipe connecting the four way valve and the third heat exchanger with each other; and a fifth pipe connecting the second heat exchanger and the compressor with each other, and the third pipe is connected with the fifth pipe.

A first check valve may be provided in the third pipe and configured to block refrigerant from flowing in the four way valve from the fifth pipe.

The heat pump apparatus may include a blowing fan disposed to face the second heat exchanger and the third heat exchanger and configured to blow air toward the second heat exchanger and the third heat exchanger.

The heat pump apparatus may include a bypass pipe connected to both sides of the second expansion valve; and a second check valve disposed in the bypass pipe and configured to block a refrigerant from flowing from an inlet to an outlet of the second expansion valve.

The heat pump apparatus may include a sixth pipe having one side connected to the first heat exchanger and the other side connected with the first expansion valve, the second expansion valve and the bypass pipe; and a third check valve disposed in the sixth pipe and configured to block a refrigerant from flowing to the first heat exchanger from at least one of the first expansion valve, the second expansion valve and the bypass pipe.

The dishwasher may further include a spray arm provided in the tub and spraying wash water. Wash water introduced from the tub may be heated while passing through the first heat exchanger and transferred to the tub to be sprayed through the spray arm.

When the dishwasher performs a washing mode, the four way valve may connect the first pipe and the second pipe with each other and also connects the third pipe and the fourth pipe with each other.

When the dishwasher performs a washing mode, a refrigerant discharged from the compressor may be introduced to the first heat exchanger after passing through the first pipe and the second pipe, and a refrigerant discharged from the second heat exchanger may be introduced to the compressor after passing through the fifth pipe, and a refrigerant discharged from the third heat exchanger may be introduced to the compressor after sequentially passing through the fourth pipe, the third pipe and the fifth pipe.

When the dishwasher performs a washing mode, the first heat exchanger may be operated as a condenser configured to heat wash water and condense a refrigerant by transmitting heat to the wash water from the refrigerant, and the second heat exchanger and the third heat exchanger may be operated as an evaporator configured to evaporate a refrigerant by transferring heat to the refrigerant from air.

When the dishwasher performs a drying mode, the four way valve may connect the first pipe and the fourth pipe with each other, and separate the second pipe and the third pipe from the first pipe and the fourth pipe.

When the dishwasher performs a drying mode, a refrigerant discharged from the compressor may be introduced to the third heat exchanger after passing through the first pipe and the fourth pipe, a refrigerant discharged from the second heat exchanger may be introduced to the compressor after passing through the fifth pipe, and flow of the refrigerant into the first heat exchanger may be blocked by the first check valve and the third check valve.

When the dishwasher performs a drying mode, the second heat exchanger may be operated as an evaporator configured to evaporate a refrigerant by transferring heat to the refrigerant from air, and the third heat exchanger may be operated as a condenser configured to heat air and condense a refrigerant by transferring heat to the air from the refrigerant.

When the dishwasher performs a washing mode, the second expansion valve may be open, and when the dishwasher performs a drying mode, the second expansion valve may be closed.

The blowing fan may blow air introduced from the tub toward the second heat exchanger and the third heat exchanger, and when the dishwasher performs a washing mode, the air having passed through the third heat exchanger may be discharged to the outside of the tub, and when the dishwasher performs a drying mode, the air having passed through the third heat exchanger may be introduced to the tub.

A heat pump apparatus according to an embodiment provided in a dishwasher may include a compressor configured to compress refrigerant; a first heat exchanger to which refrigerant is introduced from the compressor, the first heat exchanger configured to heat water introduced into the tub; a first expansion valve to which refrigerant is introduced from the first heat exchanger, the first expansion valve configured to expand refrigerant; a second heat exchanger to which refrigerant is introduced from the first expansion valve; a second expansion valve disposed in parallel with the first expansion valve, the second expansion valve to which refrigerant is introduced from the first heat exchanger; a third heat exchanger disposed in parallel with the second heat exchanger, the third heat exchanger to which refrigerant is introduced from the second expansion valve; a four way valve connected with the compressor, the first heat exchanger, the second heat exchanger and the third heat exchanger and configured to change a flow path of a refrigerant; and a blowing fan disposed to face the second heat exchanger and the third heat exchanger and configured to blow air toward the second heat exchanger and the third heat exchanger.

When the dishwasher performs a washing mode, the first heat exchanger may be operated as a condenser configured to heat wash water and condense a refrigerant by transmitting heat to the wash water from the refrigerant, and the second heat exchanger and the third heat exchanger may be operated as an evaporator configured to evaporate a refrigerant by transferring heat to the refrigerant from air. when the dishwasher performs a drying mode, the second heat exchanger may be operated as an evaporator configured to evaporate a refrigerant by transferring heat to the refrigerant from air, the third heat exchanger may be operated as a condenser configured to heat air and condense a refrigerant by transferring heat to the air from the refrigerant, and flow of the refrigerant into the first heat exchanger may be blocked to limit heat exchange between the refrigerant and wash water.

A heat pump apparatus according to an embodiment may include a compressor configured to compress refrigerant; a first heat exchanger to which refrigerant is introduced from the compressor, the first heat exchanger configured to heat water introduced into the tub; a first expansion valve to which refrigerant is introduced from the first heat exchanger, the first expansion valve configured to expand refrigerant; a second heat exchanger to which refrigerant is introduced from the first expansion valve; a second expansion valve disposed in parallel with the first expansion valve, the second expansion valve to which refrigerant is introduced from the first heat exchanger; and a third heat exchanger disposed in parallel with the second heat exchanger, the third heat exchanger to which refrigerant is introduced from the second expansion valve.

Based on an operation mode of the dishwasher, the role of the first heat exchanger to the third heat exchanger may be changed to a condenser or an evaporator. When the dishwasher performs a washing mode, the heat pump apparatus may heat wash water and when the dishwasher performs a drying mode, the heat pump heat apparatus may heat air, so that the heat pump apparatus can heat both wash water and air.

When the dishwasher performs the washing mode, the first heat exchanger may be operated as the condenser, and the second heat exchanger and the third heat exchanger may be operated as the evaporator, thereby effectively heating water with a relatively large specific heat.

When the dishwasher performs the drying mode, the first heat exchanger may not be used, the second heat exchanger may be used as the evaporator, and the third heat exchanger may be operated as the condenser. Accordingly, a smaller amount of heat than the amount of the amount of heat supplied to water in the washing mode may be supplied to air having a relatively low specific heat, thereby effectively heating the air. The supply of excessive heat can be suppressed, thereby improving the energy efficiency of the heat pump apparatus.

The heat pump apparatus may include air flow part. The air flow part may include a first duct having an inlet connected with the tub and introducing air inside the tub to the air flow part; a blowing fan connected with the first duct and configured to forcibly blow air toward the air flow part; a second heat exchanger disposed to face the blowing fan and allowing refrigerant to flow therein from the first expansion valve; a third heat exchanger disposed to face the second heat exchanger and allowing refrigerant to flow therein from the second expansion valve; a damper device connected with the third heat exchanger and configured to change a flow path of air; and a second duct having an outlet connected with the tub and an inlet connected with the damper device.

Air inside the blowing fan may circulate between the air flow part and the tub. Since the air of the tub is forcibly blown to circulate the tub, the drying time may be reduced and drying efficiency may be improved, compared to circulation due to natural convection.

The heat pump apparatus may include a damper device. when the dishwasher performs the washing mode, the heat pump apparatus may use the damper device to heat wash water supplied to the tub and discharge the air forcibly circulating inside the heat pump apparatus to the outside of the tub. When the dishwasher performs the drying mode, the heat pump apparatus may use the damper device to heat air supplied to the tub and introduce the air forcibly flowing in the heat pump apparatus into the tub.

Accordingly, flow of the forcibly blown air into the tub may be blocked in the washing mode to prevent deterioration of washing efficiency due to the forcible flowing air. Only in the drying mode, air may be introduced to the tub so that drying efficiency in the tub may be improved.

A dishwasher according to an embodiment may include a tub defining a washing space and accommodating dishes; and a heat pump configured to heat wash water introduced to the tub.

When the dishwasher performs a washing mode, the heat pump apparatus may heat the wash water supplied to the tub and discharge air forcibly flowing therein to the outside of the tub. When the dishwasher performs a drying mode, the heat pump apparatus may heat the air supplied to the tub and introduce the air forcibly flowing therein into the tub.

The heat pump apparatus may include a compressor configured to compress refrigerant; a first heat exchanger to which refrigerant is introduced from the compressor, the first heat exchanger configured to heat water introduced into the tub; a first expansion valve to which refrigerant is introduced from the first heat exchanger, the first expansion valve configured to expand refrigerant; a second expansion valve disposed in parallel with the first expansion valve, the second expansion valve to which refrigerant is introduced from the first heat exchanger; and an air flow part connected with the tub, the air flow part in which air introduced from the tub flows.

The air flow part may include a first duct having an inlet connected with the tub and introducing air inside the tub to the air flow part; a blowing fan connected with the first duct and configured to forcibly blow air toward the air flow part; a second heat exchanger disposed to face the blowing fan and allowing refrigerant to flow therein from the first expansion valve; a third heat exchanger disposed to face the second heat exchanger and allowing refrigerant to flow therein from the second expansion valve; a damper device connected with the third heat exchanger and configured to change a flow path of air; and a second duct having an outlet connected with the tub and an inlet connected with the damper device.

The damper device may include a first discharge hole for discharging air introduced to the damper device to the outside of the duct; a first damper configured to selectively open and close the first discharge hole; and a second damper configured to selectively open and close an inlet of the first damper and an inlet of the second damper.

When the dishwasher performs the washing mode, the first discharge hole may be open and the inlet of the second duct may be closed so that the air introduced to the air flow part can be discharged to the outside of the tub. When the dishwasher performs the drying mode, the first discharge hole may be closed and the inlet of the second duct may be closed so that the air introduced to the air flow part can flow into the tub.

When the dishwasher performs the washing mode, the first damper may open the first discharge hole and the second damper may close the inlet of the second duct. When the dishwasher performs the drying mode, the first damper may close the first discharge hole and the second damper may open the inlet of the second duct.

The dishwasher may include a base provided under the tub and supporting the tub. The blowing fan, the second heat exchanger, the third heat exchanger and the damper device may be disposed in the base.

The first duct may include a first cell disposed outside the tub to face a lateral wall of the tub and provided in communication with the inside of the tub; and a second cell having one end that is in communication with the first cell and the other end that is in communication with the blowing fan, the second cell of which at least predetermined area is disposed in the base.

The second duct may include a first part having one end that is in communication with the damper device; and a second part in communication with the first part and protruding from the inside of the tub via a bottom plate of the tub, being in communication with the inside of the tub.

The dishwasher may include a sump provided under the tub and accommodating wash water. The sump may be disposed some area inside the base. The sump may be provided at a position that avoids the positions of the blowing fan, the second heat exchanger, the third heat exchanger and the damper device.

The dishwasher may include a four way valve connected with the compressor, the first heat exchanger, the second heat exchanger and the third heat exchanger and configured to change a flow path of a refrigerant.

The dishwasher may include a spray arm provided in the tub and spraying wash water. The wash water flowing from the tub may be heated while passing through the first heat exchanger and transferred to be sprayed through the spray arm.

The heat pump apparatus may include a first pipe connecting the four way valve and the compressor with each other; a second pipe connecting the four way valve and the first heat exchanger with each other; a third pipe connecting the four way valve and the second heat exchanger with each other; a fourth pipe connecting the four way valve and the third heat exchanger with each other; and a fifth pipe connecting the second heat exchanger and the compressor with each other, and the third pipe may be connected with the fifth pipe.

When the dishwasher performs the washing mode, the four way valve may connect the first pipe and the second pipe with each other and connect the third pipe and the fourth pipe with each other. When the dishwasher performs the drying mode, the four way valve may connect the first pipe and the fourth pipe with each other and separate the second pipe and the third pipe from the first pipe and the fourth pipe.

When the dishwasher performs the washing mode, the first heat exchanger may operated as the condenser configured to heat wash water by transferring heat to the wash water from refrigerant, and the second heat exchanger and the third heat exchange may be operated as the evaporator configured to evaporate refrigerant by transferring heat to the refrigerant from air. When the dishwasher performs the drying mode, the second heat exchanger may be operated as the evaporator configured to evaporate refrigerant by transferring heat to the refrigerant from air and the third heat exchanger may be operated as the condenser configured to heat air and condense refrigerant by transferring heat to the air from the refrigerant. Heat exchange between the refrigerant and the wash water may be limited by blocking the flow of refrigerant into the first heat exchanger.

A heat pump according to an embodiment may include a compressor configured to compress refrigerant; a first heat exchanger to which refrigerant is introduced from the compressor, the first heat exchanger configured to heat water introduced into the tub; a first expansion valve to which refrigerant is introduced from the first heat exchanger, the first expansion valve configured to expand refrigerant; a second expansion valve disposed in parallel with the first expansion valve, the second expansion valve to which refrigerant is introduced from the first heat exchanger; and an air flow part connected with the tub, the air flow part in which air introduced from the tub flows. The air flow part may include a first duct having an inlet connected with the tub and introducing air inside the tub to the air flow part; a blowing fan connected with the first duct and configured to forcibly blow air toward the air flow part; a second heat exchanger disposed to face the blowing fan and allowing refrigerant to flow therein from the first expansion valve; a third heat exchanger disposed to face the second heat exchanger and allowing refrigerant to flow therein from the second expansion valve; a damper device connected with the third heat exchanger and configured to change a flow path of air; and a second duct having an outlet connected with the tub and an inlet connected with the damper device.

The dishwasher including the heat pump apparatus may selectively heat wash water or air, thereby improving energy efficiency of the dishwasher, compared to the dishwasher using the electric heater.

The dishwasher including the heat pump apparatus may use the four way valve to change the flow path of the refrigerant, so that heat both the wash water and air supplied to the tub may be heated, thereby reducing the entire volume of the heat pump apparatus and effectively heating the wash water or air based on the operation mode of the dishwasher.

In addition, in the dishwasher including the heat pump apparatus according to the present invention, when heating wash water requiring a relatively large amount of heat, the plurality of evaporators may be used. When heating wash water requiring a relatively small amount of heat, one evaporator may be used. Due to this structure, the number of evaporators may be optimized based on the required amount of heat, thereby effectively reducing energy loss due to use of unnecessary devices.

In addition, in the dishwasher including the heat pump apparatus according to the present invention, the air forcibly blown by the blowing fan may circulate the tub and the air flow part. Accordingly, air may circulate inside the tub. Since the air circulates the tub smoothly, evaporation of wash water on the surfaces of the dishes accommodated in the tub may be promoted by the circulating air to effectively reduce the drying time, thereby improving drying efficiency of the dishwasher.

In addition, in the dishwasher including the heat pump apparatus according to the present invention, the path of the air forcibly flowing may be changed by the damper device. The air forcibly flowing in the air flow part may not be introduced to the tub in the washing mode but may be introduced to the tub in the drying mode. Accordingly, the air cooled to be a low temperature air while passing through the second heat exchanger and the third heat exchanger in the washing mode may not be introduced to the tub but discharged outside so that the tub may not be cooled by the low temperature air, thereby improving washing efficiency of the dishwasher.

The above-described aspects, features and advantages are specifically described hereunder with reference to the accompanying drawings such that one having ordinary skill in the art to which the present invention pertains can easily implement the invention In the disclosure, detailed descriptions of known technologies in relation to the invention are omitted if they are deemed to make the gist of the invention unnecessarily vague. Below, preferred embodiments according to the invention are specifically described with reference to the accompanying drawings. In the drawings, identical reference numerals can denote identical or similar components.

The singular forms "a", "an" and "the" are intended to include the plural forms as well, unless explicitly indicated otherwise. It should be further understood that the terms "comprise" or "include" and the like, set forth herein, are not interpreted as necessarily including all the stated components or steps but can be interpreted as excluding some of the stated components or steps or can be interpreted as including additional components or steps.

<FIG> is a schematic sectional view of a dishwasher according to an embodiment.

Referring to <FIG>, the dishwasher may include a housing defining an exterior design; a tub <NUM> defining a washing space <NUM> inside the housing and accommodating dishes as washing targets; a door <NUM> rotatably coupled to a base <NUM> and disposed in front of the tub <NUM> to open and close the tub <NUM>; a sump <NUM> provided under the tub and storing wash water; a storage part <NUM> provided inside the tub <NUM> and storing washing targets therein; and a spray arm <NUM> spraying wash water toward the washing targets stored in the storage part. At this time, the dishes may be bowls, plates, spoons and chopsticks and other cooking utensils, for example.

The tub <NUM> may define the washing space <NUM> and accommodate dishes. The storage part <NUM> and the spray arm <NUM> may be provided in the washing space <NUM>. The tub may have one open surface and the open surface may be open and closed by the door <NUM>.

The door <NUM> may be rotatably coupled to the housing to selectively open and close the washing space <NUM>. For example, a lower portion of the door <NUM> may be hingedly coupled to the housing.

In this instance, the door <NUM> may rotatable on a hinge to open and close the tub <NUM>. When the door <NUM> is open, the storage part <NUM> may be pulled out of the dishwasher and the pulled-out storage part <NUM> may be supported by the door <NUM>.

The sump <NUM> may include a storage portion <NUM> storing wash water; a sump cover <NUM> that separates the storage part <NUM> from the tub <NUM>; a water supply portion <NUM> supplying wash water to the storage portion <NUM> from the outside; a water discharge portion discharging the wash water stored in the storage portion <NUM> to the outside; and a water supply pump <NUM> and a supply path <NUM> for supply the wash water of the storage part <NUM> to the spray arm <NUM>.

The sump cover <NUM> may be provided above the sump <NUM> to separate the sump <NUM> from the tub <NUM>. The sump cover <NUM> may include a plurality of collecting holes for collecting holes for collecting the wash water sprayed into the washing space <NUM> through the spray arm <NUM>.

Specifically, the wash water sprayed through the spray arm <NUM> may fall to a lower portion of the washing space <NUM>, and may be collected again in the storage portion <NUM> of the sump <NUM> after passing through the sump cover <NUM>.

The water supply pump <NUM> may be provided in a side or lower area of the storage portion <NUM>, and configured to supply wash water to the spray arm <NUM>.

One end of the water supply pump <NUM> may be connected with the storage portion <NUM> and the other end thereof may be connected to the supply path <NUM>. An impeller <NUM>, a motor <NUM>, etc. may be provided inside the water supply pump <NUM>. When the motor <NUM> is supplied electric power, the impeller <NUM> may rotate and the wash water stored in the storage portion <NUM> may be supplied to the spray arm <NUM> via the supply path <NUM>.

The supply path <NUM> may selectively supply the wash water to the spray arm <NUM> from the water supply pump <NUM>.

The supply path <NUM> may include a first supply path <NUM> connected to a lower spray arm <NUM>, an upper spray arm <NUM>, and a supply path conversion valve <NUM> for selectively opening and closing the supply paths <NUM>, <NUM> and <NUM>. At this time, the supply path conversion valve <NUM> may control the supply paths <NUM>, <NUM> and <NUM> to be opened sequentially or simultaneously.

At least one storage part <NUM> for storing dishes may be provided inside the washing space <NUM>. <FIG> shows a dishwasher including two storage parts <NUM> but the embodiment is not limited thereto.

For example, the dishwasher may include only one storage part or three or more storage parts. In this instance, the number of the spray arms may be variable based on the number of the storage parts.

The storage part <NUM> may include a lower rack <NUM> and an upper rack <NUM> for storing dishes. The lower rack <NUM> may be disposed in the washing space <NUM> and dishes may be stored on the lower rack. The upper rack <NUM> may be disposed above the lower rack <NUM> and dishes may be stored on the upper rack. Meanwhile, a top rack may be disposed in a space defined between an upper area of the upper rack <NUM> and a top nozzle <NUM>. Dishes may be stored on the top rack.

The lower rack <NUM> may be disposed above the sump <NUM> and the upper rack <NUM> may be disposed above the lower rack <NUM>. The lower rack <NUM>, the upper rack <NUM> and the top rack may be pulled out through the open surface of the tub <NUM>.

To this end, a rail-type holder may be provided on an inner surface of the tub <NUM> and a wheel may be provided on a lower surface of the rack <NUM>, <NUM>. A user may pull out the storage part <NUM> and put dishes therein or take out the dishes having been washed.

The spray arm may be provided inside the tub <NUM> and configured to spray wash water toward the dishes stored in the storage part <NUM>. The spray arm <NUM> may include a lower spray arm <NUM>, an upper spray arm <NUM> and a top nozzle <NUM>.

The lower spray arm <NUM> may be rotatably provided below the lower rack <NUM> and spray wash water to the dishes. The upper spray arm <NUM> may be rotatably provided between the lower rack <NUM> and the upper rack <NUM>, and may spray wash water to the dishes.

The lower ram <NUM> may be rotatably mounted on the sump cover <NUM> and configured to spray wash water toward the dishes stored in the lower rack <NUM>. The upper spray arm <NUM> may be disposed above the lower spray arm <NUM>, to spray wash water toward the dishes stored in the upper rack <NUM>. The top nozzle <NUM> may be provided in an upper area of the washing space <NUM> and configured to spray wash water to the lower rack <NUM> and the upper rack <NUM>.

As described above, the first supply path <NUM> may supply wash water to the lower spray arm <NUM>. The second supply path <NUM> and <NUM> may supply wash water to the upper spray arm <NUM> and the top nozzle <NUM>.

Referring to <FIG>, the dishwasher may include a base <NUM>. The base may be disposed on a bottom of the tub <NUM> and the tub <NUM> may be mounted on the base <NUM>. The base <NUM> may provide a space in which the sump <NUM> is accommodated, and also a space in which a pump, a hot air supply device <NUM> and other various mechanisms provided in the dishwasher are accommodated.

Accordingly, the base <NUM> may support the entire dishwasher with its outer wall and the outer wall may define the space in which various mechanism are accommodated.

The dishwasher according to an embodiment may spray high-temperature wash water to the dishes accommodated in the tub <NUM> by heating the wash water introduced into the tub, thereby increasing washing efficiency for the dishes and performance of the dishwasher.

The dishwasher according to the invention includes a heat pump apparatus <NUM> configured to heat the wash water introduced into the tub <NUM>. The heat pump apparatus <NUM> may heat the wash water so that the dishes can be washed by high-temperature wash water to improve the performance of the dishwasher.

In general, an electric heater heating wash water by converting an electric energy into heat may be used as a device for heating wash water. A coefficient of performance COP is a measure used to indicate the energy efficiency of the electric heater and the heat pump apparatus <NUM>. The higher the coefficient of performance, the higher the energy efficiency of the device.

The performance coefficient of the electric heater is only <NUM> at the maximum. However, the dishwasher according to the embodiment may heat wash water by using the heat pump apparatus <NUM> instead of the electric heater. The heat pump apparatus <NUM> may move heat to a high-temperature thermal reservoir from a low-temperature thermal reservoir to make high-temperature heat, and heat the wash water by using the high-temperature heat.

Due to this structure, the heat pump apparatus <NUM> may have the coefficient of performance exceeding <NUM>, and most of the coefficients of performance of the heat pump used actually may exceed <NUM>. Accordingly, the dishwasher according to the embodiment that may heat wash water by using the heat pump apparatus <NUM> may have increased energy efficiency, compared to the conventional dishwasher heating wash water by using the electric heater.

Hereinafter, the heat pump apparatus according to an embodiment will be described in detail. <FIG> is a piping view schematically showing a heat pump apparatus according to an embodiment. In the drawings from <FIG>, a flow direction of the refrigerant and wash water is illustrated as an arrow in a piping system and a flow direction of air is illustrated as a separate arrow.

The heat pump apparatus <NUM> is mounted in the dishwasher to heat the wash water introduced into the tub <NUM>. The heat pump apparatus <NUM> includes a compressor <NUM>, a condenser <NUM>, an expansion valve <NUM> and an evaporator <NUM>.

The compressor <NUM>, the condenser <NUM>, the expansion valve <NUM> and the evaporator <NUM> are connected via a piping system. A refrigerant flows through the piping. The refrigerant functions as a working fluid that absorbs or dissipates heat by changing its phase from liquid to gas or conversely from gas to liquid, while sequentially circulating through the compressor <NUM>, the condenser <NUM>, the expansion valve <NUM> and the evaporator <NUM>.

The compressor <NUM> compresses a refrigerant and discharge a high-temperature-high-pressure refrigerant. The condenser <NUM> is provided with the refrigerant from the compressor <NUM> and heat the water introduced into the tub. Accordingly, the refrigerant may lose heat while flowing through the condenser <NUM> only to be condensed from gas to liquid. The refrigerant is introduced into the expansion valve <NUM> from the condenser and the expansion valve expands the refrigerant. The refrigerant may be expanded to be chilled while passing through the expansion valve <NUM>.

The evaporator <NUM> is provided with the refrigerant from the expansion valve <NUM> and may discharge the refrigerant to the compressor <NUM> to evaporate the refrigerant by absorbing heat from room-temperature air and the stored water. The refrigerant may be evaporated into gas by absorbing heat while passing through the evaporator <NUM>.

The refrigerant is introduced to the evaporator <NUM> from the expansion valve <NUM> and the evaporator <NUM> may evaporate the refrigerant by absorbing heat from air inside the tub <NUM>. In other words, the refrigerant may flow inside the evaporator <NUM> and the evaporator <NUM> may evaporate the refrigerant by absorbing heat from air inside the tub.

The refrigerant may absorb or dissipate heat by changing its phase while circulating the compressor <NUM>, the condenser <NUM>, the expansion valve <NUM> and the evaporator <NUM>. First, the refrigerant may be compressed to be a high-temperature-and-high-pressure refrigerant, while passing through the compressor <NUM>.

The refrigerant may emit QH of heat while passing through the condenser <NUM>. The heat emitted from the condenser <NUM> may be used in heating the wash water. Accordingly, flow paths through which the refrigerant and the wash water pass, respectively, are provided in the condenser <NUM>. The refrigerant may emit heat while passing through the condenser <NUM> and it may be condensed into liquid from gas. The refrigerant having passed through the condenser <NUM> may be a mixture of liquid and gas that has a very small gas ratio or may be a sub-cooled liquid.

The refrigerant discharged from the condenser <NUM> may be expanded while passing through the expansion valve <NUM>. As a result of the expansion of the refrigerant, the temperature of the refrigerant may become lower and become a mixture gas of gas and liquid.

The refrigerant discharged from the expansion valve <NUM> may be evaporated by absorbing heat of QL1 from room-temperature air nearby, while passing through the evaporator <NUM> so that the gas ratio of the refrigerant may increase. At this time, the air of the tub <NUM> may be heated by the heated wash water or a heat pump to have somewhat high temperature air by the heated air introduced to the tub, compared to room temperature air nearby.

The refrigerant discharged from the evaporator <NUM> may be a mixed gas having a very small liquid ratio or a superheated gas.

The refrigerant discharged from the evaporator <NUM> is introduced into the compressor <NUM> again and compressed to be high-temperature-and-high-pressure gas. As described above, the refrigerant may change its phase while circulating the heat pump apparatus <NUM> so that the refrigerant may absorb heat from the evaporator <NUM>, and may emit heat from the condenser <NUM>. The heat emitted from the condenser <NUM> may heat the wash water.

Accordingly, the heat pump apparatus <NUM> may absorb heat of QL from the air of the tub <NUM>, which is a low-temperature heat reservoir, and emit heat to the wash water or air, which is a high-temperature heat reservoir, only to heat the wash water or air.

In order to actively transfer heat in the evaporator <NUM> it is appropriate to allow a large amount of air to flow toward the evaporator <NUM>. For that, the heat pump apparatus <NUM> may include a blowing fan <NUM> for blowing air toward the evaporator <NUM>.

The dishwasher may perform a washing mode configured to spray the heated wash water to the dishes stored in the tub <NUM>, and a drying mode configured to remove moisture from surfaces of the dishes by spraying heated air to the dishes stored in the tub <NUM> after the washing mode.

In an embodiment, a plurality of heat exchangers may be provided. Each of the heat exchangers may be used or not used when the washing mode or the drying mode is performed. The heat exchangers may be operated as the condenser <NUM> or the evaporator <NUM>, which will be described in detail below.

<FIG> is a piping view showing a heat pump apparatus according to an embodiment. The heat pump apparatus <NUM> includes a compressor <NUM>, a first heat exchanger <NUM>, a first expansion valve <NUM>, a second heat exchanger <NUM>, a second expansion valve <NUM>, a third heat exchanger <NUM> and a four-way valve <NUM>.

The compressor <NUM> is the same as what is described above. The first heat exchanger <NUM> has the refrigerant introduced therein from the compressor <NUM> and heat the water introduced to the tub <NUM>. The first heat exchanger <NUM> may be operated as the condenser <NUM> configured to heat the wash water and condenser the refrigerant by transferring heat to the wash water from the refrigerant. The first heat exchanger <NUM> may not be operated in the drying mode.

The first expansion valve <NUM> may have the refrigerant introduced from the first heat exchanger <NUM> and expand the refrigerant. The second heat exchanger <NUM> may have the refrigerant introduced from the first expansion valve <NUM>. The second heat exchanger <NUM> may be operated as the evaporator <NUM> in both the washing mode and the drying mode.

The second expansion valve <NUM> may be disposed in parallel with the first expansion valve <NUM>, and expand the refrigerant introduced therein from the first heat exchanger <NUM>. When the dishwasher performs the washing mode, the second expansion valve <NUM> may be open. When the dishwasher performs the drying mode, the second expansion valve <NUM> may be closed.

The third heat exchanger <NUM> may be disposed in parallel with the second heat exchanger <NUM>, and have the refrigerant introduced therein from the second expansion valve <NUM>. The third heat exchanger <NUM> may be operated as the evaporator <NUM> in the washing mode and as the condenser <NUM> in the drying mode.

The four way valve <NUM> may be connected with the compressor <NUM>, the first heat exchanger <NUM>, the second heat exchanger <NUM> and the third heat exchanger <NUM>, and may change a flowing path of the refrigerant. The four way valve <NUM> may make the flow path of the refrigerant different in each of the washing mode and the drying mode, so that it may be determined whether the first heat exchanger <NUM> to the third heat exchanger <NUM> are used or not used, or whether they are used as the condenser <NUM> or the evaporator <NUM>.

The heat pump apparatus <NUM> may include a first pipe <NUM> connecting the four way valve <NUM> and the compressor <NUM> with each other; a second pipe <NUM> connecting the four way valve <NUM> and the first heat exchanger <NUM>; a third pipe connecting the four way valve <NUM> and the second heat exchanger <NUM> with each other; a fourth pipe <NUM> connecting the four way valve <NUM> and the third heat exchanger <NUM> with each other; and a fifth pipe <NUM> connecting the second heat exchanger <NUM> and the compressor <NUM> with each other. Refrigerant may flow through each of the pipes.

At this time, the third pipe <NUM> may be connected with the fifth pipe <NUM>. Accordingly, the refrigerant flowing through the third pipe <NUM> may be introduced to the compressor <NUM>.

A first check valve <NUM> may be provided in the third pipe <NUM> to block the refrigerant from flowing to the four way valve from the fifth pipe <NUM>. The check valve may allow the refrigerant to flow only in an arrow direction and not to flow the refrigerant in the direction opposite to the arrow direction by blocking.

The first check valve <NUM> may allow the refrigerant to flow toward the compressor <NUM> from the four way valve and suppress it from flowing toward the four way valve <NUM> from the second heat exchanger <NUM>.

The heat pump apparatus <NUM> may include a blowing fan <NUM> disposed to face the second heat exchanger <NUM> and the third heat exchanger <NUM> and configured to blow air toward the second heat exchanger <NUM> and the third heat exchanger <NUM>.

The blowing fan <NUM> may allow a large amount of air to flow toward the second heat exchanger <NUM> and the third heat exchanger <NUM> by blowing air toward them. Accordingly, the amount of heat transfer between the refrigerant flowing inside the second heat exchanger <NUM> and the third heat exchanger <NUM> and the air flowing outside the second heat exchanger <NUM> and the third heat exchanger <NUM> may be increased.

The blowing fan <NUM> may be disposed at a position facing the second heat exchanger <NUM>. The second heat exchanger <NUM> may be positioned between the blowing fan <NUM> and the third heat exchanger <NUM>. Due to this structure, the air forcibly blown by the blowing fan <NUM> may pass through the third heat exchanger <NUM> after passing through the second heat exchanger <NUM>.

The heat pump apparatus <NUM> may include a bypass pipe <NUM> and a second check valve <NUM>. The bypass pipe <NUM> may be connected to both sides of the second expansion valve <NUM>. When the second expansion valve <NUM> is closed, the refrigerant may bypass the second expansion valve <NUM> through the bypass pipe <NUM>.

The second check valve <NUM> may be disposed in the bypass pipe <NUM> and configured to block the refrigerant from flowing to an outlet from an inlet of the second expansion valve <NUM> through the bypass pipe <NUM>.

In the washing mode, the second expansion valve may be open. At this time, the flow of the refrigerant to flow from the inlet to the outlet of the second expansion valve <NUM> through the bypass pipe <NUM> may be blocked by the second check valve <NUM>.

In the drying mode, the second expansion valve <NUM> may be closed. At this time, the refrigerant may flow from the outlet of the second expansion valve to the inlet through the bypass pipe <NUM> and may be blocked from flowing from the inlet of the second expansion valve <NUM> to the outlet by the second check valve <NUM>.

The heat pump apparatus <NUM> may include a sixth pipe <NUM> and a third check valve <NUM>. The sixth pipe <NUM> may have one side connected with the first heat exchanger <NUM> and the other side connected with the first expansion valve <NUM>, the second expansion valve <NUM> and the bypass pipe <NUM>.

The third check valve <NUM> may be disposed in the sixth pipe <NUM> and configured to block the refrigerant from flowing to the first heat exchanger <NUM> from at least one of the first expansion valve <NUM>, the second expansion valve <NUM> and the bypass pipe <NUM>.

In the drying mode, the first heat exchanger <NUM> may not be used. Accordingly, the third check valve <NUM> may be disposed in the sixth pipe <NUM> connected to the outlet to the first heat exchanger <NUM> so that the refrigerant may not flow in the first heat exchanger <NUM>. Accordingly, the flow of the refrigerant to flow backward into the first heat exchanger <NUM> through the outlet of the first heat exchanger <NUM> may be blocked by the third check valve <NUM>.

The dishwasher may include a sump <NUM> provided under the tub <NUM> to store wash water; and a spray arm <NUM> provided in the tub <NUM>, while being connected with the sump <NUM>, to spray wash water. The detailed structure of the sump <NUM> and the spray arm <NUM> is already described above.

In the washing mode, the heated wash water may be sprayed to the tub <NUM> through the spray arm. The wash water introduced from the tub <NUM> in the washing mode may be heated while passing through the first heat exchanger <NUM> and transferred to the tub <NUM> to be sprayed through the spray arm. At this time, the first heat exchanger <NUM> may be operated as the condenser <NUM> configured to heat the wash water by absorbing heat from the refrigerant.

<FIG> is a piping view to describe an operation of a heat pump apparatus when heating wash water. The operation of the heat pump apparatus <NUM> when the dishwasher heats wash water in the washing mode will be described, referring to <FIG>.

When the dishwasher performs the washing mode, the four way valve <NUM> may connect the first pipe <NUM> and the second pipe <NUM>, and may connect the third pipe <NUM> and the fourth pipe <NUM>. At this time, the first pipe <NUM> may not be connected with the third pipe <NUM> or the fourth pipe <NUM>, and the second pipe <NUM> may not be connected with the third pipe <NUM> or the fourth pipe <NUM>.

Accordingly, the first pipe <NUM> and the second pipe <NUM> may be separated from the third pipe <NUM> and the fourth pipe <NUM>, and the third pipe <NUM> and the fourth pipe <NUM> may be also separated from the first pipe <NUM> and the second pipe <NUM>.

When the dishwasher performs the washing mode, the refrigerant discharged from the compressor <NUM> may be introduced to the first heat exchanger <NUM> after passing through the first pipe <NUM> and the second pipe <NUM>. The refrigerant discharged from the second heat exchanger <NUM> may be introduced into the compressor <NUM> after passing the fifth pipe <NUM>. The refrigerant discharged from the third heat exchanger <NUM> may be introduced to the compressor <NUM> after sequentially passing through the fourth pipe <NUM>, the third pipe <NUM> and the fifth pipe <NUM>.

In <FIG>, the flow path of the refrigerant in the washing mode may be indicated as an arrow. The refrigerant discharged from the compressor <NUM> may be introduced to the first heat exchanger <NUM> after sequentially passing through the first pipe <NUM>, the four way valve <NUM> and the second pipe <NUM>.

At this time, since the refrigerant introduced to the first heat exchanger <NUM> has a high temperature, it may be deprived of heat by the wash water flowing in the first heat exchanger <NUM> to be condensed. Accordingly, the first heat exchanger <NUM> may be operated as the condenser <NUM> configured to heat wash water.

The refrigerant discharged from the first heat exchanger <NUM> may be expanded to have a low temperature, while passing through the first expansion valve <NUM> and the second expansion valve <NUM>, which are connected in parallel with each other. In the washing mode, the second expansion valve <NUM> may be open to allow the flow of the refrigerant and the bypass pipe <NUM> may be blocked from the flow of the refrigerant by the second check valve <NUM>.

The refrigerant discharged from the first expansion valve <NUM> may be introduced to the compressor <NUM> after sequentially passing through the second heat exchanger <NUM>, the third pipe <NUM> and the fifth pipe <NUM>. Since the first check valve <NUM> is disposed in the third pipe <NUM>, the refrigerant may be blocked from flowing in the four way valve through the third pipe <NUM> by the first check valve <NUM>.

The refrigerant discharged from the second expansion valve <NUM> may be introduced to the compressor <NUM> after sequentially passing through the third heat exchanger <NUM>, the fourth pipe <NUM>, the four way valve <NUM>, the third pipe <NUM> and the fifth pipe <NUM>.

In the washing mode, low-temperature refrigerant, and air inside the tub <NUM>, which is relatively high temperature, may flow inside the second heat exchanger <NUM> and the third heat exchanger <NUM>. Accordingly, the refrigerant passing through the second heat exchanger <NUM> and the third heat exchanger <NUM> may take heat from the air of the tub <NUM> to be evaporated. The second heat exchanger <NUM> and the third heat exchanger <NUM> may be operated as the evaporator <NUM>.

That is, when the dishwasher performs the washing mode, the first heat exchanger <NUM> may transfer heat to the wash water from the refrigerant to heat the wash water, and may be operated as the condenser <NUM> configured to condense the refrigerant. The second heat exchanger <NUM> and the third heat exchanger <NUM> may be operated as the evaporator <NUM> configured to evaporate refrigerant by transferring heat to the refrigerant from air.

<FIG> is a piping view to describe an operation of a heat pump apparatus <NUM> when heating air. The operation of the heat pump apparatus <NUM> when the dishwasher performs the drying mode configured to dry the dishes stored in the tub by using heated air after the washing mode will be described, referring to <FIG>. In <FIG>, a flow path of the refrigerant in the drying mode is indicated as an arrow in a pipe.

In the drying mode, the flow of wash water may stop in the heat pump apparatus <NUM>. Accordingly, in the drying mode, wash water may not be sprayed to the tub <NUM> but heated air may be sprayed to the tub by an air flow part <NUM> instead.

When the dishwasher performs the drying mode, the four way valve <NUM> may connect the first pipe <NUM> and the fourth pipe <NUM>, and the second pipe <NUM> and the third pipe <NUM> may be separated from the first pipe <NUM> and the fourth pipe <NUM>.

At this time, the first pipe <NUM> may not be connected with the second pipe <NUM> or the third pipe <NUM>. The fourth pipe <NUM> may not be connected with the second pipe <NUM> or the third pipe <NUM>. Here, the second pipe <NUM> and the third pipe <NUM> may be connected with each other.

When the dishwasher performs the drying mode, the refrigerant discharged from the compressor <NUM> may be introduced to the third heat exchanger <NUM> after passing through the first pipe <NUM> and the fourth pipe <NUM>. The refrigerant discharged from the second heat exchanger <NUM> may be introduced to the compressor <NUM> after passing through the fifth pipe <NUM>. The flow of the refrigerant into the first heat exchanger <NUM> may be blocked by the first check valve <NUM> and the third check valve <NUM>.

Referring to <FIG>, the structure will be described in detail. The refrigerant discharged from the compressor <NUM> may be introduced to the third heat exchanger <NUM> after sequentially passing through the first pipe <NUM>, the four way valve <NUM> and the fourth pipe <NUM>. The high temperature refrigerant passing through the third heat exchanger <NUM> may be deprived of heat by air to be condensed. Accordingly, the third heat exchanger <NUM> may be operated as the condenser <NUM> in the drying mode.

In the drying mode, the second expansion valve <NUM> may be closed. The opening and closing of the second expansion valve <NUM> may be performed by a controller provided in the dishwasher and configured to control the overall operation of the dishwasher.

After bypassing the closed second expansion valve <NUM> and passing through the bypass pipe <NUM>, the second check valve <NUM> and the sixth pipe <NUM>, the refrigerant may be introduced to the first expansion valve <NUM>. The sixth pipe <NUM> may be connected with the first heat exchanger <NUM> but the third check valve <NUM> may be disposed in the sixth pipe <NUM> so that the flow of the refrigerant into the first heat exchanger <NUM> may be blocked by the third check valve <NUM>.

The refrigerant may be a low temperature state while passing through the first expansion valve <NUM>. The low temperature refrigerant may flow in the second heat exchanger <NUM> to be evaporated by taking heat from the relatively high temperature air flowing inside the second heat exchanger <NUM>. In the drying mode, the second heat exchanger <NUM> may be operated as the evaporator <NUM>.

The refrigerant discharged from the second heat exchanger <NUM> may flow into the compressor <NUM> after passing through the fifth pipe <NUM>. The fifth pipe <NUM> may be connected with the third pipe <NUM> and the third pipe <NUM> may be connected with the four way valve <NUM>. However, since the first check valve <NUM> is disposed in the third pipe <NUM>, the flow of the refrigerant into the first heat exchanger <NUM> via the four way valve <NUM> may be blocked by the first check valve <NUM>.

Accordingly, in the drying mode, the flow in the first heat exchanger <NUM> may be blocked by the first check valve <NUM> and the third check valve <NUM> and wash water may not flow, so that the first heat exchanger <NUM> may not be used as the evaporator <NUM> or other heat exchanger.

When the dishwasher performs the drying mode, the second heat exchanger <NUM> may be operated as the evaporator <NUM> to evaporate the refrigerant by transferring heat to the refrigerant from air. The third heat exchanger <NUM> may be operated as the condenser <NUM> to condense the refrigerant by transferring heat to air and heating the air.

In the washing mode, the heated wash water may be introduced to the tub <NUM>, not air. Conversely, in the drying mode, the heated air may be introduced to the tub, not wash water.

The blowing fan <NUM> may blow the air flowing from the tub <NUM> toward the second heat exchanger <NUM> and the third heat exchanger <NUM>. The blowing fan <NUM> may be operable in both the washing mode and the drying mode. Accordingly, it is necessary the air forcedly blown by the blowing fan <NUM> should not be introduced to the tub.

When the dishwasher performs the washing mode, the air having passed through the third heat exchanger <NUM> may be discharged outside the tub. When the dishwasher performs the drying mode, the air having passed through the third heat exchanger <NUM> may be introduced to the tub <NUM>.

The air having passed through the third heat exchanger <NUM> after blown by the blowing fan <NUM> may pass through a damper device <NUM> and may be sprayed into the tub <NUM> through a second duct <NUM> provided in the tub <NUM>.

As shown in <FIG> as an arrow, in the washing mode, the damper device <NUM> may be open to the outside of the dishwasher and the air blown by the blowing fan <NUM> may be discharged outside from the damper device <NUM>. Accordingly, the air blown by the blowing fan <NUM> may be blocked from flowing in the tub <NUM>.

In the drying mode, the damper device <NUM> may not be open to the outside and air may be sprayed into the tub <NUM> through the damper device <NUM> and the second duct <NUM>.

In the embodiment, the heat pump apparatus <NUM> is used in selectively heating wash water or air so that energy efficiency of the dishwasher can be enhanced.

In the embodiment, the four way valve <NUM> may be used in changing the flow path of the refrigerant so that both the wash water and air supplied to the tub <NUM> can be heated. Accordingly, the entire volume of the heat pump apparatus <NUM> may be reduced and wash water or air can be effectively heated according to the operation mode of the dishwasher.

In the embodiment, when heating wash water that requires a relatively large amount of heat, the plurality of evaporators <NUM> may be used. When heating air that requires a relatively small amount of heat, one evaporator <NUM> may be used. Due to this structure, the number of evaporators <NUM> may be optimized based on the required amount of heat, thereby effectively reducing energy loss that might occur due to use of unnecessary devices.

Hereinafter, the structure of heating wash water by using the heat pump apparatus <NUM> in the washing mode will be described in detail, referring to the accompanying drawing. <FIG> is a piping view to describe a pipe connection structure between a heat pump apparatus <NUM> according to an embodiment and a tub <NUM>.

The dishwasher may include the sump <NUM> disposed under the tub <NUM> and storing wash water; and the spray arm provided in the tub <NUM>, while being connected with the sup <NUM>, and spraying wash water the detailed structure of the sump <NUM> and the spray arm is already described above.

The first heat exchanger <NUM> and the sump <NUM> may be connected through a pipe to circulate wash water therethrough. The dishwasher may include the first water supply path <NUM> and the water supply pump <NUM>. The first water supply path <NUM> may be provided in the supply path <NUM>.

The first water supply path <NUM> may connect the sump <NUM> and the spray arm and wash water may flow through the first water supply path <NUM>. The water supply pump <NUM> may be disposed in the first water supply path <NUM> to supply wash water to the spray arm from the sump <NUM>. The detailed structure of the water supply pump <NUM> is already described above.

The dishwasher may include the circulation path <NUM> and the circulation pump <NUM>. The circulation path <NUM> may be provided in the supply path <NUM>. The circulation path <NUM> may be connected with the first heat exchanger <NUM> and the sump <NUM>, and wash water may circulate therethrough. The circulation path <NUM> may be connected with the first heat exchanger <NUM> and the wash water may be heated by absorbing heat from the refrigerant flowing in the first heat exchanger <NUM>, while passing through the first heat exchanger <NUM> along the circulation path <NUM>. The refrigerant may be deprived of heat by the wash water in the first heat exchanger <NUM> operated as the condenser <NUM> to be condensed.

The circulation pump <NUM> may be disposed in the circulation path <NUM> to circulate wash water between the heat exchanger <NUM> and the sump <NUM>. The wash water may be introduced to the first heat exchanger <NUM> by the circulation pump <NUM> to be heated. The heated wash water discharged from the first heat exchanger <NUM> may flow in the sump <NUM> through the circulation path <NUM>. The heated wash water introduced to the sump <NUM> may be pumped by the water supply pump <NUM> and flow into the spray arm to be sprayed to the tub <NUM> through the spray arm.

The wash water may fall from the tub <NUM> and flow into the sump <NUM>. The sump <NUM> may be disposed under the tub <NUM>. Accordingly, the wash water may fall down under the tub <NUM> by the gravity to flow in the sump <NUM>.

Some of the wash water introduced to the sump <NUM> may flow between the first heat exchanger <NUM> and the sump <NUM>, and the other may flow between the sump <NUM> and the tub <NUM>. At this time, the water supply pump <NUM> and the circulation pump <NUM> may be operated simultaneously. The heated wash water and the cold wash water falling from the tub <NUM> may be continuously mixed by the first heat exchanger <NUM>. Accordingly, the wash water sprayed to the tub <NUM> through the spray arm after flowing in the spray arm from the sump <NUM> may be heated.

<FIG> is a piping view to describe a connection structure between a heat pump apparatus <NUM> according to another embodiment and a tub <NUM>. Hereinafter, repeated description compared to what is described above will be omitted.

In the dishwasher according to another embodiment, after falling down from the tub <NUM> and flowing into the sump <NUM>, wash water may sequentially pass through the first heat exchanger <NUM> and the spray arm to be sprayed to the tub <NUM>. That is, the wash water flowing into the sump <NUM> may be introduced to the spray arm after passing through the first heat exchanger <NUM>.

The dishwasher according to the embodiment shown in <FIG> may include a second water supply path <NUM>, a water supply pump <NUM> and a third water supply path <NUM>. The second water supply path <NUM> and the third water supply path <NUM> may be provided in the supply path <NUM>. The second water supply path <NUM> may be configured to connect the sump <NUM> and the first heat exchanger <NUM> with each other.

The water supply pump <NUM> may be disposed in the second water supply path <NUM> to supply wash water to the spray arm. The water supply pump <NUM> may be equal to what is described above, except that it is disposed in the second water supply path <NUM>. The third water supply path <NUM> may connect the first heat exchanger <NUM> and the spray arm with each other.

The wash water introduced to the first heat exchanger <NUM> through the second water supply path <NUM> may be heated while passing through the first heat exchanger <NUM>. The heated wash water discharged from the first heat exchanger <NUM> may flow along the third water supply path <NUM> to be introduced to the spray arm and sprayed to the tub.

In the embodiment shown in <FIG>, the tub, the sump <NUM>, the water supply pump <NUM> and the first heat exchanger <NUM> may constitute one circulation flow system. Accordingly, the wash water may be heated while passing through the first heat exchanger <NUM> and the heated wash water may be introduced to the spray arm, only with the existing water supply pump <NUM> without the need to add a separate pump.

<FIG> is a perspective view partially showing a dishwasher according to an embodiment. <FIG> is a view showing an area of a dishwasher in which an air flow part <NUM> is disposed. For clear description, <FIG> illustrates that a bottom plate 2b of the tub is transparent to make visible the inside of the base <NUM> provided under the base plate 2b. Hereinafter, referring to the drawings, the structure of the heat pump apparatus <NUM> will be described in detail.

The dishwasher may include the base <NUM> provided under the tub and supporting the tub <NUM>. The tub <NUM> may include a lateral wall 2a surrounding an internal space at both sides and a rear side; and a bottom plate 2a integrally formed with the lateral wall 2a as one body. The base <NUM> and the tub <NUM> may be partitioned off by the bottom plate 2b. The bottom plate 2b may be partially recessed and some area of the sump <NUM> may be disposed in the recessed portion.

The inside of the base <NUM> may be provided as some space except for a support structure. Accordingly, various components of the dishwasher may be disposed in the inner space of the base <NUM>. For example, the sump <NUM> may be disposed in the base <NUM>. Some of the compressor <NUM>, the blowing fan <NUM>, the first heat exchanger <NUM>, the second heat exchanger <NUM>, the third heat exchanger <NUM> and the air flow part <NUM> may be disposed in the base <NUM>.

In an embodiment, the first heat exchanger <NUM> disposed in the base <NUM> may be a plate heat exchanger. The space capable of accommodating the first heat exchanger <NUM> may be limited in the base <NUM>. Accordingly, if the condenser is fabricated as a tube type heat exchanger, the volume of the condenser could become so large due to a considerably long tube that it could be difficult to dispose the condenser in the base <NUM>.

Conversely, a plate heat exchanger may increase heat exchange efficiency between two working fluids (here, wash water and refrigerant). Compared with the tube type heat exchanger, the plat heat exchanger may have the same heat exchange efficiency with the tub heat exchanger, even with a smaller volume.

Accordingly, in the embodiment, the entire volume may be reduced by manufacturing the first heat exchanger <NUM> as the plate heat exchanger that can be easily mounted in the base <NUM>. Due to this structure, space efficiency of the dishwasher can be improved.

In addition, the plate heat exchanger may control the heat exchange capacity by changing a distance between plates. By constituting the first heat exchanger <NUM> as the plate heat exchanger, it may be possible to effectively respond to changes in the heat exchange capacity required for the first heat exchanger <NUM>.

<FIG> is a perspective view of an air flow part <NUM> according to an embodiment. <FIG> is a view transparently showing some components of <FIG>.

The heat pump apparatus <NUM> may include an air flow part <NUM>. The air flow part <NUM> may be configured forcibly blow air inside the tub and heat the forcibly flowing air, in the drying mode. The air flow part <NUM> may include a first duct <NUM>, a blowing fan <NUM>, a second heat exchanger <NUM>, a third heat exchanger <NUM>, a damper device <NUM>, a second duct <NUM>, a cover <NUM> and a guide portion <NUM>.

The first duct <NUM> may have an inlet connected with the tub <NUM> so that air inside the tub <NUM> may be introduced to the air flow part <NUM>. The first duct <NUM> may be connected with the blowing fan <NUM> so that the air inside the tub <NUM> may be introduced to the air flow part <NUM> through the first duct <NUM> by the blowing fan <NUM>.

The first duct <NUM> may include a first cell <NUM> and a second cell <NUM>. The first cell <NUM> and the second cell <NUM> may be integrally formed with each other. The first cell <NUM> may be disposed outside the tub <NUM> to face the lateral wall 2a of the tub <NUM>, in communication with the inside of the tub <NUM>. A communication hole may be formed at a contact area between the first cell <NUM> and the lateral wall 2a of the tub <NUM>.

The first cell <NUM> may extend in a vertical direction of the dishwasher, in contact with the outside of the lateral wall 2a. The first cell <NUM> may be disposed in an upper portion of the base, outside the tub <NUM>.

The second cell <NUM> may have one end in communication with the first cell and the other end in communication with the blowing fan <NUM>, with at least predetermined area disposed in the base <NUM>. The second cell <NUM> may be bent and extended from one end of the first cell <NUM> to become in communication with the blowing fan <NUM>.

The blowing fan <NUM> may be connected with the first duct <NUM> and configured to forcibly blow air to the air flow part <NUM>. One end of the blowing fan <NUM> may be connected with the second cell <NUM> and the other structure of the blowing fan <NUM> is already described above.

The second heat exchanger <NUM> may be disposed to face the blowing fan <NUM> and may have refrigerant introduced therein from the first expansion valve <NUM>. The detailed description of the second heat exchanger <NUM> is already made above. The third heat exchanger <NUM> may be disposed to face the second heat exchanger <NUM> and may have the refrigerant introduced therein from the second expansion valve <NUM>. The detailed description of the third heat exchanger <NUM> is already made above.

For example, the second heat exchanger <NUM> and the third heat exchanger <NUM> may be provided as tube heat exchangers. Accordingly, the second heat exchanger <NUM> and the third heat exchanger <NUM> may be provided with a coupling pipe so that a pipe in which the refrigerant flows may be coupled to the coupling pipe. The coupling pipe may protrude to the outside of the second heat exchanger <NUM> and the third heat exchanger <NUM> or it may be a part of a tube.

The blowing fan <NUM> may be disposed to face the second heat exchanger <NUM>. The second heat exchanger <NUM> may be disposed between the blowing fan <NUM> and the third heat exchanger <NUM>. Due to this structure, the air forcibly blown by the blowing fan <NUM> may sequentially pass through the blowing fan <NUM>, the second heat exchanger <NUM> and the third heat exchanger <NUM>.

The damper device <NUM> may be connected with the third heat exchanger <NUM> and configured to change the flow path. The damper device <NUM> will be described in detail below, referring to the accompanying drawings.

The second duct <NUM> may have an outlet connected with the tub <NUM> and an inlet connected with the damper device <NUM>. In the drying mode, the air having passed through the damper device <NUM> may be introduced to the tub <NUM> via the second duct <NUM>.

The second duct <NUM> may include a first part <NUM> and a second part <NUM>. The first part <NUM> and the second part <NUM> may be integrally formed with each other. The first part <NUM> may have one end in communication with the damper device <NUM>. The second part <NUM> may be in communication with the first part <NUM> and protrude to the inside of the tub <NUM> by penetrating the bottom plate 2b of the tub <NUM> to communicate with the inside of the tub <NUM>.

The forcedly blowing air may pass through the second part <NUM> and be introduced to the tub <NUM>. In the washing mode, it is necessary to suppress the wash water from flowing into the air flow part through an opening of the second part <NUM>. Accordingly, a cap may be coupled to one end of the second part <NUM> to suppress the flow of wash water into the air flow part <NUM>.

The cover <NUM> may have one side connected with the damper device <NUM> and the other side connected with the guide portion <NUM>. An inner space may be formed in the cover <NUM>. The second heat exchanger <NUM> and the third heat exchanger <NUM> may be accommodated in the inner space. In addition, the cover <NUM> may provide a flow space through which the forcedly flowing air passes while contacting a surface of the second heat exchanger <NUM> and a surface of the third heat exchanger <NUM>.

The guide portion <NUM> may have one side connected with the blowing fan <NUM> and the other side connected with the cover <NUM>. The guide portion <NUM> may guide the flow of air passing through the second heat exchanger <NUM> and the third heat exchanger <NUM> after discharged from the flowing fan <NUM>.

<FIG> is a view of <FIG> from a different direction. <FIG> is a view showing a state where a first damper <NUM> of <FIG> is open.

In the washing mode, wash water may be sprayed to the tub <NUM>. In the drying mode, air may be sprayed to the tub <NUM>. The blowing fan <NUM> disposed in the air flow part <NUM> may be operated in both the washing mode and the drying mode.

This it because air has to supply heat to the evaporator <NUM> in both the washing mode and the drying mode and thus the blowing fan <NUM> has to be operated in both the washing mode and the drying mode to forcibly blow air.

The air blown by the blowing fan <NUM> may circulate air inside the air flow part <NUM> and the tub <NUM>. In the drying mode, the circulation of air may increase the flow of air inside the tub, thereby increasing drying efficiency.

However, there is no need to circulate air in the washing mode. In the washing mode, when air is introduced to the tub <NUM> from the air flow part <NUM>, the temperature of the tub <NUM> and the temperature of the wash water sprayed to the tub <NUM> could become lower.

In other words, both the second heat exchanger <NUM> and the third heat exchanger <NUM>, through which the forcibly flowing air passes, may be operated as the evaporators <NUM>. Accordingly, the air passing through the second heat exchanger <NUM> and the third heat exchanger <NUM> could loss heat to the refrigerant to have the low temperature.

When air is circulated in the washing mode, the air cooled to be a low temperature state while passing through the second heat exchanger <NUM> and the third heat exchanger <NUM> may be introduced to the tub <NUM> to lower the temperature of the tub. Accordingly, the temperature of the wash water might be lowered together, thereby reducing washing efficiency.

Therefore, in the washing mode, it is necessary to discharge the air forcibly blown by the blowing fan <NUM> outside the dishwasher, not flowing into the tub again.

In case the dishwasher performs the washing mode, the heat pump apparatus <NUM> according to an embodiment may heat the wash water supplied to the tub <NUM> and discharge the air forcibly flowing therein to the outside of the tub <NUM>. When the dishwasher performs the drying mode, the heat pump apparatus <NUM> may heat the air supplied to the tub <NUM> and introduce the air forcibly flowing inside the heat pump apparatus <NUM> to the tub <NUM>.

The structure of the heat pump apparatus <NUM> configured to heat and spray wash water to the tub <NUM> in the washing mode is already described above. Hereinafter, air flow in the washing mode and the drying mode will be described.

The air flow part <NUM> may include the damper device <NUM>. The damper device <NUM> may change flow path of air. In the washing mode, the forcibly flowing air may be discharged to the outside of the tub <NUM>, not flowing into the tub <NUM>, by the operation of the damper device <NUM>. In the drying mode, the forcibly flowing air may not be discharged to the outside of the tub <NUM> but flow into the tub <NUM>, by the operation of the damper device <NUM>. The damper device <NUM> may include a first discharge hole <NUM>, a first damper <NUM> and a second damper <NUM>.

The damper device <NUM> may be provided in the air flow part <NUM> and disposed in the base <NUM> together with some area of the air flow part <NUM>. The first discharge hole <NUM> may discharge the air introduced to the damper device <NUM> to the outside of the duct. The first discharge hole <NUM> may be open toward the outside from the damper device <NUM>. Accordingly, the air discharged from the first discharge hole <NUM> may be discharged to the outside of the dishwasher through the base <NUM>.

The first damper <NUM> may be configured to selectively open and close the first discharge hole <NUM>. The first damper <NUM> may be coupled to a body of the damper device <NUM> by a hinge mechanism. Accordingly, the first damper <NUM> may be hingedly rotated to selectively open and close the first discharge hole <NUM>. The hinge rotation of the first damper <NUM> may be controlled by a controller.

The second damper <NUM> may be configured to selectively open and close the inlet of the second duct <NUM>. The second duct will be described below, referring to <FIG> and <FIG>.

In the washing mode, the first discharge hole <NUM> may be open and the inlet of the second duct <NUM> may be closed. Accordingly, in the washing mode, the air forcibly flowing in the air flow part <NUM> may not be introduced to the tub but discharged to the outside through the first discharge hole <NUM>.

Conversely, in the drying mode, the first discharge hole <NUM> may be closed and the inlet of the second duct <NUM> may be open. Accordingly, in the drying mode, the air forcibly flowing in the air flow part <NUM> may pass through the second duct <NUM> and flow into the tub <NUM>.

<FIG> is a perspective view showing a state where an air flow part <NUM> is mounted in a base <NUM>. <FIG> is a view in which a sump <NUM> is omitted in <FIG>.

The sump <NUM> may be disposed in a predetermined area of the base <NUM> and it may be provided at a position avoiding the positions at which the blowing fan <NUM>, the second heat exchanger <NUM>, the third heat exchanger <NUM> and the damper device <NUM> are disposed, respectively.

In the sump <NUM>, wash water has to smoothly flow in the washing process so that it is appropriate to disposed the sump <NUM> at a position spaced apart from the positions of the blowing fan <NUM>, the second heat exchanger <NUM>, the third heat exchanger <NUM> and the damper device <NUM>, which could become obstacles hindering the flow of wash water in the sump <NUM>. With the same reason, it is also appropriate to dispose the sump <NUM> at a position spaced apart from the positions of the first heat exchanger <NUM> and the compressor <NUM>.

Similarly, the cover <NUM> accommodating the second heat exchanger <NUM> and the third heat exchanger <NUM>, and the guide portion <NUM> having both ends connected with the cover and the blowing fan <NUM>, respectively, may be disposed at positions that are spaced apart from the position of the sump <NUM>. Meanwhile, the first cell <NUM> connected with the tub <NUM> in the first duct <NUM> may be disposed on one side of the tub <NUM> and at least predetermined area of the second cell <NUM> connected with the blowing fan <NUM> may be disposed at position that avoids the position of the sump <NUM> in the base <NUM>.

<FIG> is a partial view showing a state where a second damper <NUM> is closed. <FIG> is a partial view showing a state where a second damper <NUM> is open.

The second damper <NUM> may be disposed at an inlet of the second duct <NUM>, that is, a path of air flow between the damper device <NUM> and the second duct <NUM> the second damper <NUM> may be coupled to a body of the damper device <NUM> by a hinge mechanism. Accordingly, the second damper <NUM> may be hingedly rotated to selectively open and close the inlet of the second duct <NUM>. The hinge rotation of the second damper <NUM> may be controlled by the controller.

When the dishwasher performs the washing mode, the first damper <NUM> may open the firs discharge hole <NUM> and the second damper <NUM> may close the inlet of the second cut <NUM>. This is realized by the controller controlling the hinge rotation of the first damper <NUM> and the second damper <NUM>.

Accordingly, when the dishwasher performs the washing mode, the first discharge hole <NUM> may be open and the inlet of the second duct <NUM> may be closed so that the air flowing into the air flow part <NUM> may be discharged to the outside of the tub <NUM>. So, in the washing mode, the air forcibly flowing in the air flow part <NUM> may be blocked by the second damper <NUM> to be discharged to the base <NUM> through the first discharge hole <NUM>, not to be introduced into the tub <NUM>.

When the dishwasher performs the drying mode, the first damper <NUM> may close the first discharge hole <NUM> and the second damper <NUM> may open the inlet of the second duct <NUM>. Also, this may be realized by the controller controlling the hinge rotation of the first damper <NUM> and the second damper <NUM>.

Accordingly, when the dishwasher performs the drying mode, the first discharge hole <NUM> may be closed and the inlet of the second duct <NUM> may be open so that the air flowing into the air flow part <NUM> may be introduced into the tub <NUM>.

Due to this structure, the air forcibly flowing in the air flow part <NUM> may be blocked by the first damper <NUM> not to be discharged outside. In the drying mode, the air forcibly blown by the blowing fan <NUM> may circulate the tub <NUM> and the air flow part <NUM>. Since the air circulates the tub <NUM> smoothly, evaporation of wash water on the surfaces of the dishes accommodated in the tub <NUM> may be promoted by the circulating air to effectively reduce the drying time, thereby improving drying efficiency of the dishwasher.

Claim 1:
A dishwasher comprising:
a tub (<NUM>) defining a washing space (<NUM>) and accommodating dishes; and
a heat pump apparatus (<NUM>) configured to heat wash water introduced into the tub (<NUM>),
wherein the heat pump apparatus (<NUM>) comprises,
a compressor (<NUM>) configured to compress refrigerant;
a first heat exchanger (<NUM>) to which refrigerant is introduced from the compressor (<NUM>) when the dishwasher performs a washing mode, the first heat exchanger (<NUM>) configured to heat water introduced into the tub (<NUM>);
a first expansion valve (<NUM>) to which refrigerant is introduced from the first heat exchanger (<NUM>) when the dishwasher performs the washing mode, the first expansion valve (<NUM>) configured to expand refrigerant;
a second heat exchanger (<NUM>) to which refrigerant is introduced from the first expansion valve;
characterized in that
the heat pump apparatus (<NUM>) further comprises:
a second expansion valve (<NUM>) disposed in parallel with the first expansion valve (<NUM>), the second expansion valve (<NUM>) to which refrigerant is introduced from the first heat exchanger (<NUM>) when the dishwasher performs the washing mode; J Z
a third heat exchanger (<NUM>) disposed in parallel with the second heat exchanger (<NUM>), the third heat exchanger (<NUM>) to which refrigerant is introduced from the second expansion valve (<NUM>) when the dishwasher performs the washing mode; J Z and
a four way valve (<NUM>) connected with the compressor, the first heat exchanger (<NUM>), the second heat exchanger (<NUM>) and the third heat exchanger (<NUM>) and configured to change a flow path of a refrigerant.