Patent Description:
A dishwasher is an electric home appliance machine that sprays wash water onto objects to be washed in order to remove foreign matter from the objects.

A conventional dishwasher generally includes a tub that defines a washing space, a rack provided in the tub for receiving objects to be washed, a spray arm for spraying wash water to the rack, a sump for storing wash water, and a pump for supplying the wash water stored in the sump to the spray arm.

Meanwhile, some examples of the conventional dishwasher are configured to wash objects to be washed using heated wash water or to supply steam to objects to be washed in order to wash or sterilize the objects.

The conventional dishwasher further includes a steam generator for generating steam and a steam nozzle for spraying the steam, generated by the steam generator, to the tub.

In addition, the conventional dishwasher uses an algorithm of performing a final rinsing cycle after a rinsing cycle is completed, and spraying heated wash water through the spray arm in the final rinsing cycle such that the temperature of dishes are increased, thereby increasing washing force and achieving rapid drying. Subsequently, a waiting time is generally allocated for the wash water on the dishes to vaporize due to the temperature of the dishes and such that a user does not bum his/her hands when taking the dishes out of the dishwasher.

Since the heated wash water is sprayed through the spray arm in the final rinsing cycle, however, the amount of water that is supplied is increased. <CIT> discloses a control method for a dishwasher.

An object of the present invention devised to solve the problem lies on a control method of a dishwasher that is capable of spraying steam through a spray arm.

Another object of the present invention devised to solve the problem lies on a control method of a dishwasher that uses a smaller amount of water than when spraying heated water through a spray arm in order to perform a drying cycle and that is capable of completing the drying cycle within a short time.

Another object of the present invention devised to solve the problem lies on a control method of a dishwasher that is capable of reducing the time necessary to increase the temperature of dishes in order to reduce energy consumption and to achieve rapid drying and that is capable of reducing the amount of water that is used.

A further object of the present invention devised to solve the problem lies on a control method of a dishwasher that is capable of preventing damage to a heater and the reduction of the lifetime of the heater as the result of the heater being heated due to the use of steam for a long time.

The object of the present invention can be achieved by providing a control method of a dishwasher according to claim <NUM>, including a tub for receiving objects to be washed, a plurality of spray arms for spraying wash water to the objects, and a steam nozzle for spraying steam to the objects, the control method including a main washing cycle of washing the objects, a rinsing cycle of rinsing the washed objects using wash water, and a drying cycle of drying the objects after the rinsing is completed, wherein the drying cycle includes spraying steam, received from a steam source, to the objects to increase the temperature of the objects (a steam spraying step) and resupplying water to the steam source in order to prevent the steam source from being heated after the steam spraying step (a cooling step).

The steam spraying step includes spraying steam through the steam nozzle (a first steam spraying step) and spraying steam through at least one of the spray arms (a second steam spraying step).

The control method further includes selecting a predetermined course or option (a course/option selection step), wherein the course/option selection step may include selecting at least one from among a first course, in which the first steam spraying step is performed in the drying cycle, a second course, in which the second steam spraying step is performed in the drying cycle, a third course, in which the first steam spraying step and the second steam spraying step are performed simultaneously, and a fourth course, in which the first steam spraying step and the second steam spraying step are performed sequentially.

The rinsing cycle may include spraying room-temperature wash water to the objects in order to rinse the objects (a final rinsing step).

In the case in which the objects are rinsed using heated wash water in the rinsing cycle, a pause period may be provided for a predetermined time after the rinsing cycle.

The steam spraying step may be performed for a predetermined time.

Steam may be intermittently sprayed at the steam spraying step.

The drying cycle includes supplying water necessary to generate steam to the steam source (a steam water supply step) and supplying power to a heater to generate steam (a heater operation step).

The drying cycle further includes providing a pause period such that the steam sprayed to the objects is vaporized after the steam spraying step (a waiting step).

The steam source may include a sump for storing wash water and a sump heater provided in the sump.

The steam source may include a sump for storing wash water, a pump for supplying the wash water stored in the sump to the spray arms, and a pump heater provided in the pump.

At the cooling step, a wait may be performed for a predetermined time after the water is resupplied.

The drying cycle may further include discharging water from the steam source after the cooling step (a drainage step).

The control method may further include sensing the weight of an upper rack, in which the objects are placed (a weight sensing step), wherein, when the weight of the upper rack is equal to or greater than a predetermined weight, both the first steam spraying step and the second steam spraying step may be performed.

When the weight of the upper rack is less than the predetermined weight, only the first steam spraying step may be performed.

A dishwasher may include a cabinet, a tub provided in the cabinet for receiving objects to be washed, a plurality of spray arms for spraying wash water to the objects, a sump for storing wash water, a pump for supplying the wash water stored in the sump to the spray arms, a distribution unit for selectively supplying the wash water, supplied by the pump, to at least one of the spray arms, and a pump heater provided in the pump for generating steam, wherein the steam generated by the pump heater is selectively supplied to at least one of the spray arms via the distribution unit.

The distribution unit may include a rotary member rotatably provided on the lower surface of the tub and openings provided in the rotary member so as to selectively communicate with supply paths connected to the spray arms, a space communicating with the pump for storing wash water or steam may be defined under the distribution unit, and the wash water or steam stored in the space may be selectively supplied to the spray arms through the openings as the result of the rotation of the rotary member.

The dishwasher may further include a steam path connected to the pump and a steam nozzle provided in the tub.

The present invention has the effect of providing a control method of a dishwasher that is capable of spraying steam through a spray arm.

In addition, the present invention has the effect of providing a control method of a dishwasher that uses a smaller amount of water than when spraying heated water through a spray arm in order to perform a drying cycle and that is capable of completing the drying cycle within a short time.

In addition, the present invention has the effect of providing a control method of a dishwasher that is capable of reducing the time necessary to increase the temperature of dishes in order to reduce energy consumption and to achieve rapid drying and that is capable of reducing the amount of water that is used.

In addition, the present invention has the effect of providing a control method of a dishwasher that is capable of preventing damage to a heater and the reduction of the lifetime of the heater as the result of the heater being heated due to the use of steam for a long time.

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

All terms disclosed in this specification correspond to general terms understood by persons having ordinary skill in the art to which the present invention pertains unless the terms are specially defined. If the terms disclosed in this specification conflict with general terms, the terms may be understood on the basis of their meanings as used in this specification.

It should be noted herein that the construction and control method of a device which will hereinafter be described are given only for illustrative purposes, and that the protection scope of the invention is not limited thereto.

The present invention relates to a control method of a dishwasher that is capable of spraying steam from the front or the rear of a tub. <FIG> is a view showing an example of a dishwasher. <FIG> is a view showing the lower part of the dishwasher. <FIG> is a perspective view showing a sump, a pump, and supply paths provided in the dishwasher.

As shown in <FIG> and <FIG>, the dishwasher, denoted by reference numeral <NUM>, may include a cabinet <NUM>, a tub <NUM> provided in the cabinet <NUM> for receiving objects to be washed, spray arms <NUM>, <NUM>, and <NUM> for spraying wash water to the objects, a sump <NUM> for storing wash water, and a door <NUM> for opening and closing an opening <NUM> formed in the cabinet <NUM>.

The cabinet <NUM> defines the external appearance of the dishwasher. The opening <NUM> is formed in one side of the cabinet <NUM>. The opening <NUM> communicates with the interior of the tub <NUM>.

A washing space <NUM> is defined in the tub <NUM>. Racks, in which the objects are received, may be provided in the washing space <NUM>. The racks may include an upper rack <NUM> provided in the upper part of the tub <NUM> and a lower rack <NUM> provided below the upper rack <NUM>.

The tub <NUM> is opened and closed by the door <NUM>, which is provided at one surface of the cabinet <NUM> such that a user opens the door <NUM> and withdraws the upper rack <NUM> and the lower rack <NUM> from the tub <NUM>.

In the case in which the racks include the upper rack <NUM> and the lower rack <NUM>, the spray arms <NUM>, <NUM>, and <NUM> may include an upper arm <NUM> for spraying wash water to the upper rack <NUM> from under the upper rack <NUM>, a lower arm <NUM> for spraying wash water to the lower rack <NUM> from under the lower rack <NUM>, and a top arm <NUM> for spraying wash water to the upper rack <NUM> from above the upper rack <NUM>.

The wash water sprayed to the objects by the spray arms <NUM>, <NUM>, and <NUM> may be collected in the sump <NUM>.

The sump <NUM> includes a first storage unit <NUM> provided under the tub <NUM> to store wash water. The first storage unit <NUM> stores wash water containing foreign matter removed from the objects.

The sump <NUM> is provided at the top thereof with a sump cover <NUM>, by which the sump <NUM> is partitioned from the tub <NUM>. In this case, the sump cover <NUM> may be provided with a collection hole <NUM>, through which the interior of the tub <NUM> communicates with the interior of the sump <NUM>.

Meanwhile, the sump <NUM> is connected to a water source (not shown) through a water supply path <NUM>. The water supply path <NUM> may be opened and closed by a water supply valve <NUM>, which is controlled by a controller (not shown).

The wash water stored in the sump <NUM> is discharged out of the dishwasher through a drainage path <NUM> and a drainage pump <NUM>.

Meanwhile, the dishwasher <NUM> further includes a pump <NUM> for supplying the wash water stored in the sump <NUM> to the spray arms <NUM>, <NUM>, and <NUM>.

The pump <NUM> may include a body <NUM> fixed in the cabinet <NUM>, a sump partition <NUM> for partitioning the inner space of the body <NUM> into a first chamber C1 and a second chamber C2, a communication hole <NUM> formed through the sump partition <NUM> for allowing the first chamber C1 and the second chamber C2 to communicate with each other therethrough, an introduction part <NUM> connected between the sump <NUM> and the first chamber C1, a wash water discharge part <NUM> provided in the second chamber C2 such that wash water is discharged through the wash water discharge part <NUM>, an impeller <NUM> provided in the second chamber C2, and a heater assembly H provided in the bottom of the first chamber C1.

The pump <NUM> is connected to the sump <NUM> through a connection path <NUM>. The connection path <NUM> is connected to the lower end of the side of the first storage unit <NUM> of the sump <NUM> and to the introduction part <NUM> of the pump <NUM>.

Since the heater assembly H defines the bottom of the first chamber C1, the pump <NUM> may simultaneously perform a function of heating wash water and a function of circulating wash water.

The heater assembly H may include a pump heater <NUM>, which is exposed in the first chamber C1 such that the pump heater <NUM> directly contacts wash water. Alternatively, the heater assembly H may include a pump heater <NUM>, which is provided in a heater housing <NUM>. The heater housing <NUM> may define the bottom of the first chamber C1 such that the pump heater <NUM> does not directly contact wash water. Heat may be transferred to the heater housing <NUM> such that wash water is heated by the heater housing <NUM>. In this case, the heater housing <NUM> may be made of a conductor, such as a metal, such that thermal energy can be effectively transferred to the wash water.

The impeller <NUM> moves wash water, introduced from the first chamber C1 into the second chamber C2 through the communication hole <NUM>, to the wash water discharge part <NUM>. The impeller <NUM> may be rotated by an impeller drive unit <NUM> provided outside the body <NUM>.

The drive unit <NUM> may include a motor <NUM> provided at the top of the second chamber C2 and a rotary shaft <NUM> of the motor <NUM> which is connected to the impeller <NUM> through the pump <NUM>.

Meanwhile, referring to <FIG> and <FIG>, the dishwasher may further include a second storage unit <NUM> for temporarily storing the wash water discharged from the wash water discharge part <NUM> of the pump <NUM> and a main supply path <NUM> connected between the wash water discharge part <NUM> and the second storage unit <NUM>.

The second storage unit <NUM> may be provided in the sump <NUM>. Alternatively, the second storage unit <NUM> may be provided separately from the sump <NUM>. In addition, the second storage unit <NUM> is provided under the tub <NUM>. The second storage unit <NUM> is provided in the lower part of a distribution unit <NUM>, a description of which will follow.

Consequently, the wash water pumped by the pump <NUM> is temporarily stored in the second storage unit <NUM> through the wash water discharge part <NUM>, and is then supplied into the distribution unit <NUM>. Subsequently, the distribution unit <NUM> supplies the wash water to at least one selected from among a plurality of supply paths <NUM>, <NUM>, and <NUM>.

The first supply path <NUM> and the third supply path <NUM> are provided in the upper part of the sump <NUM> (the upper part of a rotary member <NUM> provided in the distribution unit <NUM>) in the state in which one side of each of the supply paths <NUM> and <NUM> is open. The first supply path <NUM> and the third supply path <NUM> are connected respectively to the top arm <NUM> and the upper arm <NUM> along the bottom and one side of the tub <NUM>.

In addition, the second supply path <NUM> is provided in the upper part of the sump <NUM> (the upper part of the rotary member <NUM> provided in the distribution unit <NUM>) in the state in which one side of the second supply path <NUM> is open. The second supply path <NUM> is connected to the lower arm <NUM>.

The upper arm <NUM> is rotatably provided at one end of the third supply path <NUM>, and the lower arm <NUM> is rotatably provided at the second supply path <NUM>.

<FIG> is a plan view showing a sump. <FIG> is a perspective view showing a distribution unit. <FIG> is a plan view showing the distribution unit. Hereinafter, the distribution unit will be described.

As shown in <FIG> and <FIG>, the distribution unit <NUM> includes a cover <NUM> provided under the tub <NUM>, the cover <NUM> having a plurality of communication holes <NUM>, <NUM>, and <NUM> connected to the supply paths <NUM>, <NUM>, and <NUM> so as to communicate with the spray arms <NUM>, <NUM>, and <NUM>, a rotary member <NUM> for supplying wash water to at least one of the communication holes <NUM>, <NUM>, and <NUM>, a position determination means <NUM> for determining the rotational position of the rotary member <NUM>, and a rotary member drive unit <NUM> for rotating the rotary member <NUM>.

The cover <NUM> is provided at the top of the sump <NUM>. The communication holes <NUM>, <NUM>, and <NUM> include a first communication hole <NUM> connected to the first supply path <NUM>, a second communication hole <NUM> connected to the second supply path <NUM>, and a third communication hole <NUM> connected to the third supply path <NUM>.

The communication holes <NUM>, <NUM>, and <NUM> are selectively opened by the rotary member <NUM>. In other words, the rotary member <NUM> is provided under the cover <NUM>, which has the communication holes <NUM>, <NUM>, and <NUM> therein. The rotary member <NUM> is provided with two or more rotary member openings <NUM> and <NUM>.

The rotary member openings <NUM> and <NUM> may include a first opening <NUM> and a second opening <NUM>, the sizes of which are different from each other.

When the rotary member <NUM> is rotated, therefore, the rotary member openings <NUM> and <NUM> pass under the communication holes <NUM>, <NUM>, and <NUM> formed in the cover <NUM>. The rotary member <NUM> is connected to a drive shaft <NUM> of the rotary member drive unit <NUM> such that the rotary member <NUM> is rotated in one direction. When the rotary member <NUM> is rotated, the rotary member openings <NUM> and <NUM>, formed in the rotary member <NUM>, selectively open or close the communication holes <NUM>, <NUM>, and <NUM> such that wash water is supplied through the open communication holes and such that no wash water is supplied through the closed communication holes.

For example, wash water may be selectively sprayed through at least one selected from among the top arm <NUM>, the upper arm <NUM>, and the lower arm <NUM> or through a combination of two or more selected from among the top arm <NUM>, the upper arm <NUM>, and the lower arm <NUM>.

A means for determining the rotational position of the rotary member <NUM> is needed in order to open at least one of the communication holes <NUM>, <NUM>, and <NUM> by rotating the rotary member <NUM> such that wash water is supplied. In other words, a means for determining which of the communication holes <NUM>, <NUM>, and <NUM> is opened and closed by the rotary member openings <NUM> and <NUM> is needed such that wash water is sprayed through a desired one of the spray arms <NUM>, <NUM>, and <NUM>.

To this end, the position determination means <NUM> includes a cam <NUM> configured to be rotated by the rotary member drive unit <NUM> at the same phase as the rotary member <NUM>, the cam <NUM> having a plurality of protrusions <NUM>, <NUM>, and <NUM>, and a switch unit <NUM> for generating a signal based on the protrusions <NUM>, <NUM>, and <NUM> in response to the rotation of the cam <NUM> and transmitting the generated signal to a controller (not shown).

The protrusions <NUM>, <NUM>, and <NUM> may be arranged along the outer circumference of the cam such that the protrusions <NUM>, <NUM>, and <NUM> have different protruding lengths. Alternatively, the protrusions <NUM>, <NUM>, and <NUM> may be arranged along the outer circumference of the cam at different intervals.

As shown in <FIG>, the protrusions <NUM>, <NUM>, and <NUM> of the cam <NUM> may include a first protrusion <NUM>, a second protrusion <NUM>, and a third protrusion <NUM>.

The switch unit <NUM> is configured to generate a signal in response to the rotation of the cam <NUM>. Specifically, the switch unit <NUM> includes a body <NUM> and a signal generator <NUM> extending from the body so as to be selectively pushed by the protrusions <NUM> of the cam <NUM> for generating a signal. When the cam <NUM> is rotated as the result of rotation of the drive shaft <NUM>, therefore, the signal generator <NUM> is pushed by the protrusions <NUM>, <NUM>, and <NUM>, to generate a signal.

The time at which the signal generator <NUM> is pushed may be sensed by the switch unit <NUM>. The rotational positions of the cam <NUM> and the rotary member <NUM> may be determined based on the time sensed by the switch unit <NUM>. As a result, the rotary member driving unit <NUM> may be controlled so as to control the supply of wash water to the spray arms <NUM>, <NUM>, and <NUM>.

<FIG> are views showing the relationship between the rotary member and the communication holes <NUM>, <NUM>, and <NUM>.

A method of supplying wash water to the spray arms based on the communication between the openings and the communication holes in response to the rotation of the rotary member will be described with reference to <FIG>.

Referring to <FIG>, the first opening <NUM> in the rotary member <NUM> opens the second communication hole <NUM>, the second opening <NUM> in the rotary member <NUM> opens the third communication hole <NUM>, and the first communication hole <NUM> is closed. In this case, wash water is supplied to the lower arm <NUM> and the upper arm <NUM>.

Referring to <FIG>, the rotary member <NUM> and the cam <NUM> are rotated counterclockwise. As a result, the first opening <NUM> of the rotary member <NUM> opens the first communication hole <NUM>, and the second communication hole <NUM> and the third communication hole <NUM> are closed. In this case, wash water is supplied to the top arm <NUM>, but no wash water is supplied to the upper arm <NUM> or to the lower arm <NUM>.

Referring to <FIG>, the rotary member <NUM> and the cam <NUM> are rotated counterclockwise. As a result, the first opening <NUM> in the rotary member <NUM> opens the first communication hole <NUM> and the third communication hole <NUM>, and the second opening <NUM> in the rotary member <NUM> opens the second communication hole <NUM>. In this case, wash water is supplied to the top arm <NUM>, the upper arm <NUM>, and the lower arm <NUM>.

Referring to <FIG>, the rotary member <NUM> and the cam <NUM> are rotated counterclockwise. As a result, the first opening <NUM> in the rotary member <NUM> opens the third communication hole <NUM>, and the first communication hole <NUM> and the second communication hole <NUM> are closed. In this case, wash water is supplied to the upper arm <NUM>.

Referring to <FIG>, the rotary member <NUM> and the cam <NUM> are rotated counterclockwise. As a result, the first opening <NUM> in the rotary member <NUM> opens the second communication hole <NUM>, the second opening <NUM> in the rotary member <NUM> opens the first communication hole <NUM>, and the third communication hole <NUM> is closed. In this case, wash water is supplied to the top arm <NUM> and the lower arm <NUM>.

Consequently, wash water may be selectively sprayed through at least one selected from among the spray arms <NUM>, <NUM>, and <NUM> or through a combination of two or more selected from among the spray arms <NUM>, <NUM>, and <NUM>.

Meanwhile, the dishwasher <NUM> may supply steam to objects to be washed in order to improve the efficiency with which the objects are washed.

The dishwasher may further include a first steam nozzle <NUM> provided at the door <NUM> for spraying steam to the objects. Alternatively, the dishwasher may further include a second steam nozzle <NUM> provided at the rear of the tub <NUM>. Alternatively, although not shown, the dishwasher may further include a steam nozzle provided at the side of the tub <NUM>.

Meanwhile, the dishwasher may further include a docking connector <NUM> provided in the tub <NUM> for supplying steam to the first steam nozzle <NUM>, a first steam path <NUM> for connecting the docking connector <NUM> to a steam source, and a docking unit <NUM> connected to the first steam nozzle <NUM> and selectively connected to the docking connector <NUM> for receiving steam. In this case, when the door <NUM> is opened, the docking unit <NUM> and the docking connector <NUM> are separated from each other. When the door <NUM> is closed, the docking unit <NUM> and the docking connector <NUM> are connected to each other to define a path along which steam flows. Consequently, steam may be supplied to the first steam nozzle <NUM>, provided in the door <NUM>, regardless of whether the door is opened or closed.

The steam source may be configured variously. In one example, an additional steam generator (not shown) may be provided under the tub, and the first steam path <NUM> may be connected to the steam generator (not shown) such that steam is supplied to the first steam nozzle <NUM>. In another example, a sump heater (not shown) may be provided in the sump <NUM>, and the first steam path <NUM> may be connected to one side of the sump <NUM> such that steam is supplied to the first steam nozzle <NUM>.

In a further example, steam may be supplied using the pump heater <NUM>, provided in the pump <NUM>. The steam generated by the pump heater <NUM> may be supplied to one end of the first steam path <NUM>, which is connected to the pump <NUM>. Specifically, since the heater assembly H of the pump <NUM> is provided in the bottom of the first chamber C1, a predetermined amount of wash water is supplied into the first chamber C1, and then the pump heater <NUM> may be operated to generate steam. A steam discharge port <NUM> for discharging the steam, generated in the first chamber C1, out of the first chamber C1 may be further provided. The steam discharge port <NUM> may be connected to the first steam path <NUM>. The steam generated by the pump <NUM> is supplied to the first steam nozzle <NUM> via the first steam path <NUM>. The steam is sprayed into the tub.

Meanwhile, the second steam nozzle <NUM> is connected to a second steam path <NUM>, which is connected to the steam source, such that steam is supplied to the second steam nozzle <NUM>.

Referring back to <FIG>, the second steam path <NUM> is connected to the steam source. The second steam path <NUM> extends through the lower surface of the tub <NUM> such that a part of the second steam path <NUM> is provided under the tub <NUM>. In addition, the second steam path <NUM> is connected to the second steam nozzle <NUM>.

As previously described, one selected from among the steam generator, the sump heater, which is provided in the sump, and the pump heater, which is provided in the pump, may be used as the steam source.

In the case in which the pump heater <NUM>, provided in the pump <NUM>, is used as the steam source, a second connection path <NUM> is connected to the steam discharge port <NUM>, which is provided in the first chamber C1 of the pump <NUM>. Alternatively, the second connection path <NUM> may diverge from the first steam path <NUM>. The divergent part may be provided with a switch valve (not shown) for adjusting the amount of steam that is supplied to the first steam path <NUM> or the second connection path <NUM> or for opening and closing the first steam path <NUM> or the second connection path <NUM>.

Meanwhile, the dishwasher may supply steam to the tub <NUM> through the spray arms <NUM>, <NUM>, and <NUM>, rather than through the first steam nozzle <NUM> or the second steam nozzle <NUM>.

Specifically, the steam generated in the first chamber C1 by the heater assembly H may be supplied into the second chamber C2 using the property whereby hot air rises or by driving the impeller <NUM>, and the steam may be supplied and stored in the second storage unit <NUM> from the second chamber C2 through the main supply path <NUM>. In this case, steam may be selectively supplied to at least one of the spray arms <NUM>, <NUM>, and <NUM> using the distribution unit <NUM>.

The process of spraying steam is identical to the process of spraying wash water described above, and therefore a detailed description thereof will be omitted.

Consequently, the dishwasher may intensively supply steam to the upper rack <NUM> or the lower rack <NUM>, provided in the tub <NUM>, through the spray arms <NUM>, <NUM>, and <NUM>. For example, in the case in which objects to be washed are placed in the upper rack <NUM>, steam may be supplied through the upper arm <NUM> and the top arm <NUM> such that steam is intensively supplied only to the upper rack <NUM>. In the case in which objects to be washed are placed in the lower rack <NUM>, steam may be supplied through at least one selected from among the first steam nozzle <NUM>, the second steam nozzle <NUM>, and the lower arm <NUM> or through a combination of two or more selected from among the first steam nozzle <NUM>, the second steam nozzle <NUM>, and the lower arm <NUM> such that steam is intensively supplied only to the lower rack <NUM>.

<FIG> is a flowchart showing an example of a method of controlling a dishwasher according to the present invention. <FIG> is a flowchart showing an example of a method of spraying steam through spray arms in the method of controlling the dishwasher according to the present invention.

The method of controlling the dishwasher according to the present invention uses an algorithm of spraying steam to dishes that have been washed and rinsed in order to dry the dishes. Since the dishes are dried using steam, it is possible to increase the temperature of the dishes using a small amount of water, thereby reducing energy consumption.

Hereinafter, the method of controlling the dishwasher according to the present invention will be described with reference to <FIG>.

The method of controlling the dishwasher according to the present invention includes a main washing cycle (S200) of washing objects to be washed, a rinsing cycle (S300) of rinsing the washed objects using wash water, and a drying cycle (S400) of drying the objects after the rinsing of the objects is completed.

The main washing cycle (S200) is a cycle of washing dishes. Wash liquid containing washing detergent dissolved therein is sprayed to the dishes through the spray arms <NUM>, <NUM>, and <NUM>. Meanwhile, in the rinsing cycle (S300), water is sprayed to the dishes through the spray arms <NUM>, <NUM>, and <NUM> in order to remove the wash liquid from the objects.

The main washing cycle (S200) and the rinsing cycle (S300) may be repeated several times in order to completely remove foreign matter from the objects.

In addition, a pause period during which a wait is performed for a predetermined time such that the foreign matter on the objects is soaked in the sprayed wash liquid so as to be easily separated from the objects may be provided between the main washing cycle (S200) and the rinsing cycle (S300).

Meanwhile, the method of controlling the dishwasher according to the present invention may further include a pre-washing cycle (S100) of spraying a predetermined amount of water to the upper rack <NUM> and the lower rack <NUM> through the spray arms <NUM>, <NUM>, and <NUM> in order to soak the foreign matter on the objects in the water before the main washing cycle (S200). Subsequently, a wait is performed for a predetermined time such that the foreign matter on the objects is soaked in the water. In this case, room-temperature water may be sprayed, or heated water may be sprayed.

Alternatively, in the pre-washing cycle (S100), steam may be sprayed into the tub <NUM> such that the foreign matter on the objects is wetted. In this case, a high-temperature and high-humidity environment is formed in the tub, with the result that the foreign matter is effectively removed from the objects, thereby improving washing efficiency.

For a general dishwasher, in the drying cycle (S400), heated wash water is sprayed to increase the temperature of the objects, and then the objects are dried using the heat of vaporization of the water on the outer surfaces of the objects, which is generated as the result of the heated objects being cooled. In this method, however, a large amount of water is supplied to the tub through the pump <NUM> and the spray arms, with the result that water consumption is increased. Furthermore, a large amount of wash water is heated, with the result that power consumption is increased.

In order to solve the above problems, the drying cycle (S400) of the present invention includes a steam spraying step (S430) of spraying steam, received from the steam source, to the objects so as to increase the temperature of the objects.

That is, steam, rather than heated wash water, is sprayed to the objects to increase the temperature of the objects such that the objects are dried using heat of vaporization, which is generated as the result of the heated objects being cooled, and heat exchange between the latent heat of the steam and the objects.

When the dishes are dried as described above, only the water that is necessary to generate steam is consumed, with the result that the amount of water required to dry the objects is considerably reduced. Furthermore, only a small amount of water is heated, with the result that the amount of power used by the heater is reduced, thereby reducing energy consumption.

In addition, since it is not necessary to heat a large amount of water, a small amount of water is heated within a short time, thereby reducing the time for which the drying cycle is performed.

Meanwhile, the drying cycle (S400) of the present invention further includes a steam water supply step (S410) of supplying water to the steam source and a heater operation step (S420) of supplying power to the heater to increase the temperature of the heater. The steam water supply step (S410) and the heater operation step (S420) are performed before the steam spraying step (S430).

At the steam water supply step (S410), water is supplied to the storage unit <NUM> of the sump or the first chamber C1 through the water supply path <NUM>, and power is supplied to the pump heater <NUM> to generate steam. Even in the case in which the steam source for generating steam is a steam generator (not shown) or a sump heater (not shown) provided in the sump, the above step may be equally applied.

In addition, the steam water supply step (S410) and the heater operation step (S420) may be performed in reverse order as needed. In order to prevent the heater from being overheated without water, however, the steam water supply step (S410) is generally performed first, after which the heater operation step (S420) is performed.

At the steam spraying step (S430), the impeller <NUM> is driven in order to supply the steam generated in the first chamber C1 to the spray arms <NUM>, <NUM>, and <NUM>. That is, the steam generated in the first chamber C1 flows to the main supply path <NUM> through the second chamber C2. When the impeller <NUM> is driven in order to increase the pressure at which the steam is sprayed, however, the steam flows through the communication hole <NUM> between the first chamber and the second chamber, and is then supplied to the main supply path <NUM> through the wash water discharge port <NUM>. As a result, the steam sprayed through the spray arms may have a predetermined pressure.

Meanwhile, the rising cycle (S300) of the present invention may further include a final rinsing step (not shown) of spraying room-temperature wash water to the objects in order to rinse the objects.

Here, "room-temperature wash water" means water that is supplied from an external water source or water that is not heated by the heater.

In the drying cycle (S400) of the present invention, steam is sprayed to dry the objects. In the state in which the rinsing cycle (S300) is completed, therefore, the steam is sprayed to the objects to dry the objects using heat of vaporization of the steam. If the temperature of the objects (the dishes) is too high, however, it is not possible to vaporize moisture from the objects using the heat of vaporization of the steam, but water drops may be condensed on the dishes. For this reason, in the final rinsing step, which is performed before the steam spraying step, room-temperature wash water is sprayed to rinse the objects.

Meanwhile, control may be performed such that a pause period is provided for a predetermined time after the rinsing cycle (S300) and before the drying cycle (S400). In the rinsing cycle (S300) of the present invention, when the objects are rinsed using heated wash water, the objects are heated, as in a general dishwasher. The pause period is provided to cool the objects, thereby reducing the temperature of the objects. After the pause period, the steam spraying step (S430) may be performed in the drying cycle to sufficiently reduce the temperature of the dishes such that the thermal energy of the steam is transferred to the dishes.

Meanwhile, the steam spraying step (S430) may be controlled such that steam is sprayed for a predetermined time. As a result, the dishes may be sufficiently heated to a desired temperature within a short time. The desired temperature is the temperature at which moisture on the dishes is vaporized.

Alternatively, the steam spraying step (S430) may be controlled such that steam is intermittently sprayed to the objects. When the steam is intermittently sprayed, spraying of the steam and vaporization of the stem are repeatedly performed, with the result that moisture on the objects is vaporized rapidly. When the steam is intermittently sprayed, however, control is performed such that the initial spraying time is long and spraying times are gradually decreased toward the final spraying time. As a result, in the initial period, the temperature of the dishes rises to a predetermined temperature, whereby it is possible to vaporize moisture on the dishes, and, in the later period, the time during which steam is sprayed is reduced, whereby it is possible to minimize the amount of moisture formed on the dishes.

Meanwhile, the steam spraying step (S430) includes a first steam spraying step of spraying steam through the first steam nozzle <NUM> or the second steam nozzle <NUM> and a second steam spraying step of spraying steam through at least one selected from among the spray arms <NUM>, <NUM>, and <NUM>.

Meanwhile, the method of controlling the dishwasher according to the present invention further includes a course/option selection step (S1000) of selecting a predetermined course or option.

At the course/option selection step (S1000), at least one is selected from among a first course, in which the first steam spraying step is performed in the drying cycle (S400), a second course, in which the second steam spraying step is performed in the drying cycle (S400), a third course, in which the first steam spraying step and the second steam spraying step are performed simultaneously, and a fourth course, in which the first steam spraying step and the second steam spraying step are performed sequentially.

That is, when the user selects one from among the first course, the second course, the third course, and the fourth course at the course/option selection step, the dishwasher performs the first steam spraying step and/or the second steam spraying step in the drying cycle (S400) according to the selected course.

Meanwhile, the method of controlling the dishwasher according to the present invention may further include a weight sensing step (S2000) of sensing the weight of the upper rack, in which the objects are placed.

The steam spraying step in the drying cycle (S400) is set such that steam is sprayed through the steam nozzles <NUM> and <NUM>, provided under the tub <NUM>, or through the lower arm <NUM>. This is because steam is characterized in that it rises.

At the weight sensing step (S2000), the weight of the upper rack <NUM> is sensed by a weight sensor (not shown) provided at the upper rack <NUM>. When the weight of the upper rack <NUM> sensed by the weight sensor (not shown) is equal to or greater than a predetermined weight (Y at S3000), control is performed such that steam is sprayed through the upper arm <NUM> and the top arm <NUM> (S4200). Controlling the rotary member <NUM> to be rotated such that steam is sprayed through the upper arm <NUM> and the top arm <NUM> has been previously described, and a detailed description thereof will be omitted.

That is, when the weight of the upper rack <NUM> is equal to or greater than the predetermined weight, both the first steam spraying step and the second steam spraying step are performed.

Meanwhile, when the weight of the upper rack <NUM> sensed by the weight sensor (not shown) is less than the predetermined weight (N at S3000), steam is sprayed through the steam nozzles or the lower arm <NUM>, but no steam is sprayed through the upper arm <NUM> or the top arm <NUM> (S4100). Controlling the rotary member <NUM> to be rotated such that steam is sprayed through the lower arm <NUM> has been previously described, and a detailed description thereof will be omitted.

That is, when the weight of the upper rack <NUM> is less than the predetermined weight, control is performed such that only the first steam spraying step is performed.

Meanwhile, the drying cycle (S400) includes a waiting step (S450) of providing a pause period such that the steam sprayed to the objects is vaporized after the steam spraying step (S430).

At the waiting step (S450), the steam sprayed to the heated objects is vaporized, whereby the objects are dried. At the waiting step (S450), the temperature of the objects, i.e. the dishes, is gradually decreased such that moisture is completely removed from the objects. In addition, the temperature of the dishes is sufficiently decreased such that the user does not burn his/her hands when taking the dishes out of the dishwasher.

Meanwhile, the method of controlling the dishwasher according to the present invention may further include a cooling step (S450) of resupplying water to the steam source in order to prevent the steam source from being heated after the steam spraying step (S430).

In the case in which the steam source is constituted by the sump <NUM> and the sump heater (not show) or by the pump <NUM> and the pump heater <NUM>, the method of controlling the dishwasher according to the present invention may further include a drainage step (S460) of discharging residual water from the sump <NUM> or the pump <NUM>. If the residual water is discharged immediately after the steam spraying step (S430), however, the heater may be overheated, with the result that the heater may be damaged, which may cause a fire.

In order to solve the above problem, the cooling step (S450) is performed. At the cooling step (S450), water is supplied to the steam source to cool the heater, thereby preventing damage to the heater.

At the cooling step (S450), a wait is performed for a predetermined time after water is supplied to the steam source. Specifically, water is supplied into the first storage unit <NUM> of the sump <NUM> through the water supply path <NUM> to cool the sump heater (not shown). Alternatively, the impeller <NUM>, provided in the pump <NUM>, is driven to supply water to the first chamber C1 to cool the pump heater <NUM>.

Subsequently, at the drainage step (S460), the drainage pump <NUM> is driven such that residual water is discharged from the first storage unit <NUM> of the sump <NUM> or the first chamber C1 of the pump <NUM> through the drainage path <NUM>. The reason for this is that microorganisms will inhabit the residual water, with the result that the residual water will emit a terrible smell and become insanitary, if the residual water is not discharged.

Various embodiments have been described in the best mode for carrying out the invention.

The present invention has the effect of providing a dishwasher that is capable of spraying steam through a spray arm and a control method thereof.

Claim 1:
A control method of a dishwasher comprising a tub (<NUM>) for receiving objects to be washed, a plurality of spray arms (<NUM>, <NUM>, <NUM>) for spraying wash water to the objects, and a steam nozzle (<NUM>) for spraying steam to the objects, the control method comprising:
a course/option selection step comprising selecting a predetermined course or option;
a main washing cycle of washing the objects;
a rinsing cycle of rinsing the washed objects using wash water; and
a drying cycle of drying the objects after the rinsing is completed, wherein
the drying cycle comprises:
a steam water supply step comprising supplying water necessary to generate steam to the steam source;
a heater operation step comprising supplying power to a heater to generate steam;
a steam spraying step comprising spraying steam, received from a steam source comprising a heater, to the objects to increase a temperature of the objects;
a waiting step comprising providing a pause period such that the steam sprayed to the objects is vaporized after the steam spraying step; and
a cooling step comprising resupplying water to the steam source after the stream spraying step in order to cool the steam heater and thereby prevent its damage, wherein the steam spraying step comprises:
a first steam spraying step comprising spraying steam through the steam nozzle (<NUM>); and
a second steam spraying step comprising spraying steam through at least one of the spray arms (<NUM>, <NUM>, <NUM>),
wherein the course/option selection step comprises selecting at least one from among:
a first course, in which the first steam spraying step is performed in the drying cycle;
a second course, in which the second steam spraying step is performed in the drying cycle;
a third course, in which the first steam spraying step and the second steam spraying step are performed simultaneously; and
a fourth course, in which the first steam spraying step and the second steam spraying step are performed sequentially.