Patent Description:
A dishwasher is an electric home appliance 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.

In the conventional dishwasher, the wash water stored in the sump is heated using a heater provided in the sump. In addition, the conventional dishwasher further includes a steam generator for generating steam.

The conventional dishwasher further includes a steam nozzle provided at the side of the tub for spraying steam into the tub and a steam hose connected between the steam nozzle and the steam generator.

In this case, however, the steam sprayed from the side of the tub cannot wet all surfaces of the objects.

In addition, the steam is supplied only to the objects placed in the opposite sides of the rack. As a result, the steam is not supplied to the objects placed in the middle part of the rack.

Furthermore, the steam is supplied only from the side of the tub. As a result, the temperature in the washing space, which is defined in the tub, is not uniform.

An object of the present invention devised to solve the problem lies on a dishwasher that is capable of spraying steam to objects to be washed from the front or the rear of a tub.

Another object of the present invention devised to solve the problem lies on a dishwasher that is capable of spraying steam from a door.

A further object of the present invention devised to solve the problem lies on a dishwasher that prevents back pressure from being generated in a steam nozzle connected to a sump or a pump.

<CIT> discloses a dishwasher comprising a cabinet having an opening, a tub provided in the cabinet, the tub accommodating objects for washing, a spray arm for spraying wash water to the objects, a sump for storing wash water, a door for opening and closing the opening, the dishwasher further including a steam nozzle provided at an inner surface of the door and disposed in a direction facing edges of the dishes to spray steam in a horizontal direction towards the dishes. The steam nozzle is connected to a steam path located outside the tub via an inner space of the door, whereby the steam path is horizontally oriented at the bottom of the dishwasher and vertically oriented inside the door.

<CIT> discloses a dishwasher with a steam nozzle fixed to the tub. <CIT> discloses a dishwasher including a steam nozzle spraying into the tub. <CIT> discloses a dish washing machine including a steam sprayer for spraying an indicated zone with steam. <CIT> discloses a dishwasher unit and steam providing unit in which the steam discharging part sprays steam inside the tub. <CIT> discloses a steam cleaner.

The object of the present invention can be achieved by providing a dishwasher according to claim <NUM>.

A hose may be provided as the first steam path. In this case, the hose may be made of rubber. When the door is opened or closed, therefore, torsional stress applied to the hose may be distributed.

A predetermined section of the first steam path may be provided parallel to a rotary shaft of the door.

The first steam nozzle may include a nozzle housing having a steam accommodating part for temporarily storing steam therein, an accommodating part inlet provided in the nozzle housing to supply steam to the steam accommodating part, and a plurality of accommodating part outlets provided in the nozzle housing to spray the steam stored in the steam accommodating part to the objects.

A sectional area of the steam accommodating part gradually decreases as the steam accommodating part becomes more distant from the accommodating part inlet.

The steam source may be variously configured. In one example, the first steam path may receive steam from a steam generator provided under the tub. In another example, a sump heater may be provided in the sump, and the first steam path may receive steam from the sump.

In a further example, the dishwasher may further include a pump for supplying the wash water stored in the sump to the spray arm. The pump may include a pump heater, and the first steam path may receive steam from the pump.

Meanwhile, steam may be sprayed from the rear of the tub as well as the front of the door such that the steam is supplied throughout the tub.

The dishwasher according to the present invention may further include a second steam nozzle provided at the rear surface of the tub to spray steam to the objects, a second steam path connected to the second steam nozzle to supply steam to the second steam nozzle, the second steam path penetrating the bottom of the tub, and a second connection path connecting the second steam path to a steam source.

The length of the second steam path may be greater than the length of the second connection path.

The second steam nozzle may be spaced apart from the rear surface of the tub. Consequently, it is possible to prevent foreign matter from accumulating between the second steam nozzle and the rear of the tub.

The second steam nozzle may include a foreign matter blocking rib for maintaining the distance between the second steam nozzle and the rear of the tub at a predetermined distance or more. Consequently, the distance between the second steam nozzle and the rear surface of the tub may be maintained despite vibration of the tub.

The dishwasher according to the present invention may further include a back pressure prevention unit for preventing external air from being introduced into the pump.

The back pressure prevention unit may include a check valve provided in the steam nozzle or in the steam path.

The check valve may include a first partition wall having a steam path hole, through which steam is discharged, a back pressure prevention plate for opening and closing the steam path hole, a prevention plate ring formed at one side of the back pressure prevention plate, and a fixing rib provided at the first partition wall. The fixing rib is coupled to the prevention plate ring to limit the movement of the back pressure prevention plate.

The check valve may further include separation prevention ribs, provided so as to be spaced apart from an outer circumferential surface of the back pressure prevention plate. The separation prevention ribs prevent the back pressure prevention plate from being separated in a leftward and rightward direction.

The check valve may further include stoppers provided above the back pressure prevention plate so as to be spaced apart from each other. The stoppers collide with the back pressure prevention plate, raised by the pressure of steam, to provide restoring force to the back pressure prevention plate.

The check valve may further include a contact prevention rib provided on a second partition wall, which is opposite the first partition wall. The contact prevention rib prevents the back pressure prevention plate from clinging to the second partition wall due to a hydroplaning phenomenon.

The present invention has the effect of providing a dishwasher that is capable of spraying steam to objects to be washed from the front or the rear of a tub such that the steam is uniformly sprayed throughout the tub.

In addition, the present invention has the effect of providing a dishwasher including a steam nozzle provided at a door for spraying steam. Furthermore, the present invention has the effect of providing a dishwasher including a nozzle provided at the rear of a tub.

In addition, the present invention has the effect of providing a dishwasher including a path for supplying steam to a nozzle provided at a door, which is opened or closed, wherein the path is provided outside a tub such that the path is not visible, thereby improving visual safety.

In addition, the present invention has the effect of providing a dishwasher that prevents back pressure from being generated in a steam nozzle connected to a sump or a pump, thereby preventing noise from being generated in the pump.

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 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 according to the present invention.

As shown in <FIG>, the dishwasher, denoted by reference numeral <NUM>, includes a cabinet <NUM> having an opening <NUM>, a tub <NUM> provided in the cabinet <NUM> to accommodate objects for washing, spray arms <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 the opening <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> and <NUM> may include an upper arm <NUM> for spraying wash water to the upper rack <NUM> from under the upper rack <NUM>, and a lower arm <NUM> for spraying wash water to the lower rack <NUM> from under the lower rack <NUM>. In addition, a top arm <NUM> for spraying wash water to the upper rack <NUM> from above the upper rack <NUM> may further be provided.

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

The sump <NUM> includes a storage unit <NUM> provided under the tub <NUM> to store wash water. The 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>.

The water stored in the sump <NUM> is supplied to the spray arms <NUM> and <NUM> via a pump <NUM> and a first supply path <NUM>, a description of which will follow. The first supply path <NUM> is connected between the pump <NUM> and the top arm <NUM>. The first supply path <NUM> extends into the tub <NUM> through the bottom of the tub <NUM>. In addition, the first supply path <NUM> extends to the top of the tub <NUM> along one side of the tub <NUM>.

Meanwhile, the upper arm <NUM> is connected to a third supply path <NUM>, which diverges from the first supply path <NUM>. In addition, the upper arm <NUM> is rotatably coupled to one end of the third supply path <NUM>. The lower arm <NUM> is provided so as to be rotatable. The lower arm <NUM> is connected to a second supply path <NUM>, which penetrates the bottom of the tub <NUM>. The second supply path <NUM> is connected to the sump <NUM> or to a pump <NUM> such that wash water is supplied to the second supply path <NUM>.

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

The pump <NUM> may include a body <NUM> fixed in the cabinet <NUM>, a sump partition wall <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 wall <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> connected between the second chamber C2 and the first supply path <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 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 heat 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>.

<FIG> is a view showing the rear of the door provided in the dishwasher according to the present invention. <FIG> is a view showing an example of a first steam nozzle provided in the dishwasher according to the present invention. <FIG> is a view showing another example of the first steam nozzle provided in the dishwasher according to the present invention. <FIG> is a sectional view showing another example of the first steam nozzle provided in the dishwasher according to the present invention.

Hereinafter, a first steam nozzle <NUM> provided in the dishwasher according to the present invention will be described.

The dishwasher <NUM> according to the present invention may supply steam to the objects in order to improve washing efficiency.

In the conventional dishwasher, steam is sprayed only from the side of the tub. As a result, the steam is intensively sprayed to objects placed in opposite sides of the rack. That is, the steam is not uniformly sprayed throughout the tub. In addition, the temperature of the dishes is not uniform.

In order to solve the above problems, as shown in <FIG>, the dishwasher according to the present invention further includes a first steam nozzle <NUM> provided at an inner surface of the door <NUM> to spray steam to the objects.

In this case, steam may be uniformly sprayed to the dishes in the washing space. That is, the steam may not be sprayed only to the objects placed in opposite sides of the racks, but may be sprayed to all of the objects placed in the racks.

Meanwhile, the first steam nozzle <NUM> is provided at an inner surface of the door <NUM>. Here, "an inner surface of the door <NUM>" means the surface of the door <NUM> that faces the washing space <NUM> in the tub <NUM>. In other words, on the assumption that the door <NUM> includes a front panel <NUM> defining the external appearance of the dishwasher <NUM>, a rear panel <NUM> defining the inner surface of the door, and an inner space <NUM> defined between the front panel <NUM> and the rear panel <NUM>, the first steam nozzle <NUM> is provided at the rear panel <NUM> of the door <NUM>.

Meanwhile, the first steam nozzle <NUM> is provided at the lower side of the door <NUM>. In this case, it is possible to use the property whereby steam rises. As a result, the steam may be uniformly supplied to the upper part of the washing space as well as the lower part of the washing space. Furthermore, it is possible to maximally increase the temperature of the objects.

In addition, the first steam nozzle <NUM> may spray steam upward obliquely. That is, the first steam nozzle <NUM> may spray steam to the objects placed in the upper rack <NUM> or the lower rack <NUM>. Consequently, the first steam nozzle <NUM> may directly spray steam to the objects.

Referring to <FIG> and <FIG>, one example and another example of the first steam nozzle <NUM> may each include a first nozzle housing <NUM> having a first steam accommodating part <NUM> for temporarily storing steam therein, a first accommodating part inlet <NUM> provided in the first nozzle housing <NUM> to supply steam to the first steam accommodating part <NUM>, and a plurality of first accommodating part outlets <NUM> provided in the first nozzle housing <NUM> to spray the steam stored in the first steam accommodating part <NUM> to the objects.

The first nozzle housing <NUM> may include a first lower nozzle housing 421b, in which the first accommodating part inlet <NUM> is provided, and a first upper nozzle housing 421a coupled to the upper end of the first lower nozzle housing 421b. Consequently, the first steam accommodating part <NUM> is defined between the first lower nozzle housing 421b and the first upper nozzle housing 421a.

The first accommodating part outlets <NUM> are provided in the first lower nozzle housing 421b. The first upper nozzle housing 421a is provided with first outlet through holes <NUM>, through which the first accommodating part outlets <NUM> extend. Each of the first accommodating part outlets <NUM> includes a first inlet 427a communicating with the first steam accommodating part <NUM> and a first outlet 427b connected to the first inlet 427a for allowing steam to actually be discharged therethrough. That is, the first inlet 427a may communicate with the first steam accommodating part <NUM>, and the first outlet 427b may protrude outward from the first nozzle housing <NUM>.

The first nozzle housing <NUM> may further include a first nozzle insertion part <NUM> protruding outward therefrom. The first nozzle insertion part <NUM> may communicate with the first accommodating part inlet <NUM>, and may supply steam, received from the outside, to the first steam nozzle <NUM>.

The first upper nozzle housing 421a and the first lower nozzle housing 421b may be fastened to each other via a hook. A nozzle gasket <NUM> may further be provided between the first upper nozzle housing 421a and the first lower nozzle housing 421b in order to prevent steam from leaking out from between the first upper nozzle housing 421a and the first lower nozzle housing 421b.

The nozzle gasket <NUM> is made of rubber, and is manufactured by insert injection molding. The nozzle gasket <NUM> seals the gap in the first nozzle housing <NUM> to prevent the leakage of steam. In addition, the nozzle gasket <NUM> seals the gap between the inside of the door <NUM> and the first steam nozzle <NUM> to prevent foreign matter from accumulating between the door <NUM> and the first steam nozzle <NUM>.

The nozzle gasket <NUM> may be configured to cover only the gap in the first nozzle housing <NUM>. Alternatively, the nozzle gasket <NUM> may be configured to cover the entire surface of the first lower nozzle housing 421b.

The first nozzle housing <NUM> may extend in the leftward and rightward direction of the door. The first accommodating part outlets <NUM> may be provided in the first nozzle housing <NUM> so as to supply steam throughout the washing space.

Meanwhile, the first steam nozzle <NUM> may further include a first nozzle decorative part <NUM> provided outside the first nozzle housing <NUM>. The first nozzle decorative part <NUM> may improve the aesthetic appearance of the first steam nozzle <NUM>.

Meanwhile, referring to <FIG>, the first steam accommodating part <NUM> may be configured such that the sectional area of the first steam accommodating part <NUM> gradually decreases as the first steam accommodating part <NUM> becomes more distant from the first accommodating part inlet <NUM>. As the first steam accommodating part <NUM> becomes more distant from the first accommodating part inlet <NUM>, the pressure of the steam in the first steam accommodating part <NUM> is lowered. As a result, the pressure of the steam discharged from the first accommodating part outlets <NUM> may be lowered. The first steam accommodating part <NUM> may be configured as described above in order to solve this problem.

That is, the first steam accommodating part <NUM> may be configured such that the sectional area of the first steam accommodating part <NUM> gradually decreases as the first steam accommodating part <NUM> becomes more distant from the first accommodating part inlet <NUM> such that the pressure of the steam discharged from the first accommodating part outlets <NUM> is uniform.

Referring to <FIG>, the first nozzle housing <NUM> may include a plurality of ribs <NUM> for coupling the first upper nozzle housing 421a and the first lower nozzle housing 421b to each other in the sealed state. The ribs <NUM> include an upper rib 422a protruding downward from the first upper nozzle housing 421a, and a lower rib 422b protruding upward from the first lower nozzle housing 421b. Alternatively, two or more upper ribs 422a and two or more lower ribs 422b may be provided. The upper ribs 422a and the lower ribs 422b are coupled to each other to prevent steam from leaking out from the first steam accommodating part <NUM>.

Meanwhile, a hook 424a and a hook hole 424b may be provided to couple the first upper nozzle housing 421a and the first lower nozzle housing 421b to each other. The hook 424a may be provided on the first lower nozzle housing 421b, and the hook hole 424b may be provided in the first upper nozzle housing 421a. The first lower nozzle housing 421b may be fastened to the first upper nozzle housing 421a by inserting the hook 424a into the hook hole 424b.

<FIG> is a view showing a space under the tub and a space in the door. <FIG> is a view showing the state of a first steam path in the state in which the door is closed and in the state in which the door is open in the dishwasher according to the present invention.

Hereinafter, a first steam path <NUM> provided in the dishwasher according to the present invention will be described with reference to <FIG>.

In a general dishwasher, a steam path extending through one side of the tub is connected to the steam nozzle in the tub in order to provide steam to the steam nozzle, provided in the tub. In this case, a hose is provided as the steam path.

In the dishwasher according to the present invention, on the other hand, the first steam nozzle <NUM> is provided at the door <NUM>. When the door <NUM> is opened and closed, the first steam path <NUM>, connected to the first steam nozzle <NUM>, continuously moves in the tub <NUM>. As a result, the first steam path <NUM> may be separated from the first steam nozzle <NUM>, or the hose, constituting the first steam path <NUM>, may tear. Additionally, in the case in which the first steam path <NUM> is provided in the tub, the hose may be damaged due to the movement of the racks.

In order to solve the above problems, as shown in <FIG>, the dishwasher according to the present invention is characterized in that the first steam path <NUM>, which is connected to the first steam nozzle <NUM> to supply steam to the first steam nozzle <NUM>, is located outside the tub <NUM>. That is, the dishwasher according to the present invention is different from a conventional dishwasher, in which the steam path is connected to the steam nozzle in the tub.

Specifically, the first steam nozzle <NUM> is provided at one surface of the rear panel <NUM> of the door <NUM>, and the first steam path <NUM> is provided at the other surface of the rear panel <NUM> of the door <NUM>. The first steam nozzle <NUM> penetrates the rear panel <NUM> of the door <NUM> such that steam is supplied from the first steam path <NUM> to the first steam nozzle <NUM>.

The first nozzle insertion part <NUM> of the first steam nozzle <NUM> is inserted through a steam nozzle insertion hole <NUM> (see <FIG>), provided in the rear panel <NUM>, so as to protrude into the inner space <NUM> (see <FIG>) of the door <NUM>. As previously described, the nozzle gasket <NUM> is provided between the first nozzle housing <NUM> and the door <NUM> to prevent wash water from leaking out though the steam nozzle insertion hole <NUM>.

Meanwhile, the dishwasher according to the present invention further includes a steam guide <NUM> provided at an inner surface of the rear panel <NUM> of the door and optionally connected to the first nozzle insertion part <NUM> for perpendicularly changing the direction of the steam path.

Referring back to <FIG>, the steam guide <NUM> is formed in the shape of a '└'. One side of the steam guide <NUM> is connected to the first nozzle insertion part <NUM>, which protrudes perpendicularly from the rear panel <NUM>. The other side of the steam guide <NUM> is bent toward the left side or the right side the door <NUM>, and is connected to the first steam path <NUM>.

In this case, one end of the first steam path <NUM>, which is connected to the rear panel <NUM> of the door <NUM>, may be provided parallel to a rotary shaft of the door <NUM>. When the door <NUM> is opened or closed, therefore, torsional stress, rather than bending stress, is applied to the first steam path <NUM>, which is connected to the lower side of the tub <NUM>. As a result, it is possible to prevent the first steam path <NUM> from being folded or bent, thereby preventing the first steam path <NUM> from tearing.

<FIG> shows another embodiment for preventing the first steam path <NUM> from being folded or bent. Referring to <FIG>, the first steam path <NUM> may be fixed to the left side or the right side of the bottom of the tub <NUM>. That is, the first steam path <NUM> may be mounted to the left side or the right side of the tub <NUM> under the tub <NUM>. As a result, one end of the first steam path <NUM> may be connected to the rear panel <NUM> of the door <NUM> while being parallel to the rotary shaft of the door <NUM>. When the door <NUM> is opened or closed, therefore, torsional stress, rather than bending stress, may be applied to one end of the first steam path <NUM>, which is connected to the rear panel <NUM> of the tub <NUM>.

Additionally, in the case in which the first steam path <NUM> is located at the left side or the right side of the tub <NUM> under the tub <NUM>, the steam guide <NUM> may be located at one side opposite the other side at which the first steam path <NUM> is located on the basis of the horizontal middle of the door <NUM>. In this case, the length of the end of the first steam path <NUM> that is located parallel to the rotary shaft of the door <NUM> may be further increased.

Meanwhile, a hose made of rubber or plastic may be provided as the first steam path <NUM> such that the first steam path <NUM> can withstand torsional stress that is generated when the door <NUM> is opened or closed.

Meanwhile, the dishwasher <NUM> according to the present invention may include various embodiments for supplying steam to the first steam path <NUM>.

In an embodiment, an additional steam generator (not shown) may be provided under the tub <NUM>, 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 embodiment, 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 embodiment, steam may be supplied to the first steam path <NUM> using the pump heater <NUM> provided in the pump <NUM>. In this case, 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 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. In this case, a steam discharge port <NUM> (see <FIG>) 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 heater <NUM> of the pump <NUM> may be supplied to the first steam nozzle <NUM> via the first steam path <NUM>.

<FIG> is a view showing a second steam nozzle provided in the dishwasher according to the present invention. <FIG> is an exploded perspective view showing the second steam nozzle provided in the dishwasher according to the present invention. <FIG> is a sectional view and an internal perspective view showing the second steam nozzle provided in the dishwasher according to the present invention. <FIG> is a view showing foreign matter blocking ribs provided in the second steam nozzle of the present invention.

Hereinafter, the structure in which steam is sprayed from the rear of the tub will be described.

Referring to <FIG>, the dishwasher according to the present invention may include a second steam nozzle <NUM> provided at the rear surface of the tub <NUM> to spray steam to the objects, and a second steam path <NUM> for supplying steam to the second steam nozzle <NUM>.

The second steam nozzle <NUM> may be separably fixed in the first supply path <NUM>.

The second steam nozzle <NUM> may be provided at the rear surface <NUM> (see <FIG>) of the tub <NUM>. More specifically, the second steam nozzle <NUM> may be provided at the lower part of the rear surface <NUM> of the tub <NUM> (the lower part of the side of the tub). This is because steam is characterized in that it rises and because it is necessary to supply steam throughout the washing space. In addition, the second steam nozzle <NUM> may be inclined upward toward the objects. In this case, the second steam nozzle <NUM> may directly spray steam to the objects in order to effectively remove foreign matter from the objects.

Referring to <FIG> and <FIG>, the second steam nozzle <NUM> may have a structure similar to the structure of the first steam nozzle <NUM>. Specifically, the second steam nozzle <NUM> may include a second nozzle housing <NUM> having a second steam accommodating part <NUM> for temporarily storing steam therein, a second accommodating part inlet <NUM> provided in the second nozzle housing <NUM> to supply steam to the second steam accommodating part <NUM>, and a plurality of second accommodating part outlets <NUM> provided in the second nozzle housing <NUM> to spray the steam stored in the second steam accommodating part <NUM> to the objects.

The second nozzle housing <NUM> includes a second lower nozzle housing 431b, in which the second accommodating part inlet <NUM> is provided, and a second upper nozzle housing 431a coupled to the upper end of the second lower nozzle housing 431b. As a result, the second steam accommodating part <NUM> may be defined between the second lower nozzle housing 431b and the second upper nozzle housing 431a. In addition, the second accommodating part outlets <NUM> are provided in the second upper nozzle housing 431a.

The second nozzle housing <NUM> may further include a second nozzle insertion part <NUM> protruding outward. The second nozzle insertion part <NUM> may communicate with the second accommodating part inlet <NUM> to supply steam, received from the outside, to the second steam nozzle <NUM>.

Meanwhile, a back pressure prevention unit for preventing external air from being introduced into the pump <NUM> may be provided between the second steam path <NUM> and the second nozzle insertion part <NUM>. For example, a check valve <NUM> may be provided as the back pressure prevention unit. A detailed description of the back pressure prevention unit will follow.

As shown in <FIG>, the second upper nozzle housing 431a and the second lower nozzle housing 431b may be fastened to each other using a hook 434a and a hook fastening part 434b. In this case, the hook 434a may be provided on the second lower nozzle housing 431b, and the hook fastening part 434b may be provided in the second upper nozzle housing 431a. In addition, the second nozzle housing <NUM> may include a plurality of steam leakage prevention ribs <NUM> for preventing steam from leaking out from between the second upper nozzle housing and the second lower nozzle housing.

The steam leakage prevention ribs <NUM> includes upper steam leakage prevention ribs 432a provided in the second upper nozzle housing 431a, and lower steam leakage prevention ribs 432b provided in the second lower nozzle housing 431b. The upper steam leakage prevention ribs 432a and the lower steam leakage prevention ribs 432b may be engaged with each other to prevent the leakage of steam. For example, in the case in which two upper steam leakage prevention ribs 432a are provided in the second upper nozzle housing 431a, three lower steam leakage prevention ribs 432b may be provided in the second lower nozzle housing 431b. In this case, the upper steam leakage prevention ribs 432a are inserted between the lower steam leakage prevention ribs 432b in a dual sealing fashion so as to effectively prevent steam from leaking outside.

The second nozzle housing <NUM> extends in the leftward and rightward direction of the door. The second nozzle housing <NUM> may include a plurality of second accommodating part outlets <NUM>. Consequently, it is possible to supply steam throughout the washing space.

Meanwhile, the second steam accommodating part <NUM> may be configured such that the sectional area of the second steam accommodating part <NUM> gradually decreases as the second steam accommodating part <NUM> becomes more distant from the second accommodating part inlet <NUM>. As the second steam accommodating part <NUM> becomes more distant from the second accommodating part inlet <NUM>, the pressure of the steam in the second steam accommodating part <NUM> is lowered. As a result, the pressure of the steam discharged from the second accommodating part outlets <NUM> may be lowered. The second steam accommodating part <NUM> may be configured as described above in order to solve this problem.

That is, the second steam accommodating part <NUM> is configured such that the sectional area of the second steam accommodating part <NUM> gradually decreases as the second steam accommodating part <NUM> becomes more distant from the second accommodating part inlet <NUM> such that the pressure of the steam discharged from the second accommodating part outlets <NUM> is uniform.

Meanwhile, the second steam nozzle <NUM> may be spaced apart from the rear <NUM> of the tub <NUM>. This structure is provided to prevent foreign matter removed from the objects from accumulating between the second steam nozzle <NUM> and the rear <NUM> of the tub <NUM> while falling along the rear <NUM> of the tub <NUM>.

Furthermore, as shown in <FIG>, the second steam nozzle <NUM> according to the present invention may further include foreign matter blocking ribs <NUM> for maintaining the distance between the second steam nozzle <NUM> and the rear <NUM> of the tub <NUM> at a predetermined distance or more.

The foreign matter blocking ribs <NUM> may protrude from the rear of the second steam nozzle <NUM>, i.e. the second lower nozzle housing 431b. The foreign matter blocking ribs <NUM> may extend in the upward and downward direction to maintain the distance between the second steam nozzle <NUM> and the tub <NUM> and to guide the flow of wash water therebetween. Consequently, the distance between the second steam nozzle <NUM> and the rear <NUM> of the tub <NUM> is maintained despite vibration of the pump <NUM> and vibration of the tub <NUM>.

Meanwhile, referring back to <FIG>, the second steam path <NUM> is defined in the tub <NUM>. The second steam path <NUM> penetrates the bottom of the tub <NUM>. Specifically, one side of the second steam path <NUM> is connected to the second nozzle insertion part <NUM> of the second steam nozzle <NUM>, which is provided in the tub <NUM>, and the other side of the second steam path <NUM> extends through the bottom <NUM> of the tub <NUM>.

In this case, a second connection path <NUM> is provided under the tub <NUM> such that the second connection path <NUM> connects the second steam path <NUM> to the steam source. That is, the in-tub section of the path for supplying steam from the steam source to the second steam nozzle <NUM> is defined as the second steam path <NUM>, and the out-of-tub section of the path is defined as the second connection path <NUM>.

As previously described, one selected from among the steam generator, the sump heater, which is provided in the sump <NUM>, and the pump heater <NUM>, which is provided in the pump <NUM>, 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, the second connection path <NUM> may be 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 be connected to a path that diverges from the first steam path <NUM>. In this case, the divergent path may be provided with a switch valve (not shown) for opening and closing the first steam path <NUM> and the second connection path <NUM>. As a result, it is possible to adjust the amount of steam that is supplied to the first steam path <NUM> and the second connection path <NUM>.

The second connection path <NUM> is connected to the pump <NUM> and to the second steam path <NUM>, which extends through the bottom <NUM> of the tub <NUM>. Meanwhile, since the second connection path <NUM> is provided outside the tub <NUM>, steam may be cooled due to heat exchange between the steam and external air while the steam flows along the second connection path <NUM>. In this case, some of the steam flowing along the second connection path <NUM> may be condensed or frozen. As a result, the steam spray performance of the second steam nozzle <NUM> may be lowered. In order to solve this problem, it is necessary to minimize the length of the second connection path <NUM>. Consequently, the length of the second steam path <NUM> may be greater than the length of the second connection path <NUM> so as to minimize the length of the second connection path <NUM>.

<FIG> is a view showing a back pressure prevention unit for the steam nozzle provided in the dishwasher according to the present invention. <FIG> is a view showing a back pressure prevention unit for the steam path provided in the dishwasher according to the present invention. <FIG> are views showing the back pressure prevention unit of the present invention.

Hereinafter, a back pressure prevention unit of the present invention will be described.

The dishwasher according to the present invention may further include a back pressure prevention unit for preventing the introduction of external air into the sump <NUM> or the pump <NUM>.

In the case in which the first steam path <NUM> or the second steam path <NUM> is connected to the sump <NUM> or the pump <NUM>, negative pressure is generated in the sump <NUM> or the pump <NUM> when the pump <NUM> is driven to spray wash water into the tub <NUM>. Consequently, external air may be introduced into the sump <NUM> or the pump <NUM> through the first steam path <NUM> or the second steam path <NUM>.

In this case, the pressure of wash water sprayed through the spray arms <NUM> and <NUM> may be lowered, or sufficient wash water may not be sprayed through the spray arms <NUM> and <NUM>. In addition, the air may collide with the impeller <NUM>, which is provided in the pump <NUM>, whereby noise may be generated.

In order to solve these problems, the back pressure prevention unit may include a check valve <NUM>. In the case in which steam generated by the pump <NUM> is supplied to the first steam path <NUM> or the second steam path <NUM>, the check valve <NUM> may open the steam path. In the case in which the pump <NUM> is driven (i.e. when the impeller <NUM> is driven) to spray wash water into the tub <NUM>, the check valve <NUM> may close the steam path.

As shown in <FIG>, the check valve <NUM> may be provided in the first steam nozzle <NUM> or the second steam nozzle <NUM>. Alternatively, as shown in <FIG>, the check valve <NUM> may be provided in the first steam path <NUM> or the second steam path <NUM>.

First, a check valve that is equally applicable to the steam nozzle and the steam path will be described.

Referring to <FIG>, the check valve <NUM> may include a first partition wall <NUM>, having therein a steam path hole <NUM> through which steam is discharged, and a back pressure prevention plate <NUM> for opening and closing the steam path hole <NUM>. The back pressure prevention plate <NUM> opens the steam path hole <NUM> only when the pressure of steam is equal to or greater than a predetermined pressure.

Although not shown, the back pressure prevention plate <NUM> may be configured to become thicker toward the center thereof such that, when the back pressure prevention plate <NUM> is raised due to the pressure of the steam and then falls, the center of the back pressure prevention plate <NUM> is aligned with the center of the steam path hole <NUM> due to the back pressure of the pump <NUM>.

In the case in which the check valve <NUM> is provided in the steam nozzle <NUM> or <NUM>, the first partition wall <NUM> may constitute the nozzle housing <NUM> or <NUM> of the steam nozzle <NUM> or <NUM>, and the steam path hole <NUM> may constitute the accommodating part inlet <NUM> or <NUM>.

Alternatively, in the case in which the check valve <NUM> is provided in the steam path <NUM> or <NUM>, the first partition wall <NUM> may close the first steam path <NUM> or the second steam path <NUM>, and steam may be discharged through the steam path hole <NUM>.

In addition, the check valve <NUM> may further include a prevention plate ring <NUM> formed at one side of the back pressure prevention plate <NUM> and a prevention plate fixing rib <NUM> provided at the first partition wall <NUM> such that the prevention plate ring <NUM> is fitted onto the prevention plate fixing rib <NUM> to limit the movement of the back pressure prevention plate <NUM>.

Meanwhile, as shown in <FIG>, the check valve <NUM> of the present invention may further include separation prevention ribs <NUM> provided so as to be spaced apart from the outer circumferential surface of the back pressure prevention plate <NUM> to prevent the back pressure prevention plate <NUM> from being separated in the leftward and rightward direction.

Consequently, the separation prevention ribs <NUM> may prevent the leftward or rightward movement of the back pressure prevention plate <NUM>, thereby preventing the steam path hole <NUM> from becoming unable to close.

The separation prevention rib <NUM> may be provided on the first partition wall <NUM> (see <FIG>) or a second partition wall <NUM>, which is opposite the first partition wall <NUM> (see <FIG>).

In addition, as shown in <FIG>, the check valve <NUM> of the present invention may further include stoppers <NUM> provided above the back pressure prevention plate <NUM> so as to be spaced apart from each other. The stoppers <NUM> may collide with the back pressure prevention plate <NUM>, raised by the pressure of steam, to provide restoring force to the back pressure prevention plate <NUM>. The stoppers <NUM> may be made of an elastic material, such as rubber.

That is, when the back pressure prevention plate <NUM> is raised by the pressure of steam, the back pressure prevention plate <NUM> may collide with the stoppers <NUM>. At this time, the elastic force of the stoppers <NUM> acts as restoring force. As a result, the back pressure prevention plate <NUM> may return to the original position thereof.

In addition, the check valve <NUM> of the present invention may further include a contact prevention rib <NUM> provided on the second partition wall <NUM>, which is opposite the first partition wall <NUM>. The contact prevention rib <NUM> may prevent the back pressure prevention plate <NUM> from clinging to the second partition wall <NUM> due to a hydroplaning phenomenon.

The contact prevention rib <NUM> may be provided perpendicularly to a rotary shaft of the back pressure prevention plate <NUM>. The contact prevention rib <NUM> may include a plurality of contact prevention rib parts arranged at intervals. In addition, the contact prevention rib <NUM> (or grooves between the contact prevention rib parts) may be inclined such that condensed steam water can flow along the inclined surface of the contact prevention rib <NUM>, thereby preventing the occurrence of a hydroplaning phenomenon on the second partition wall <NUM>.

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 to objects to be washed from the front of a tub.

Claim 1:
A dishwasher comprising:
a cabinet (<NUM>) having an opening (<NUM>);
a tub (<NUM>) provided in the cabinet (<NUM>), the tub (<NUM>) accommodating objects for washing;
a spray arm (<NUM>; <NUM>) for spraying wash water to the objects;
a sump (<NUM>) for storing wash water;
a door (<NUM>) for opening and closing the opening (<NUM>) and including a rear panel (<NUM>) defining an inner surface of the door (<NUM>);
a first steam nozzle (<NUM>) provided at a lower side of the inner surface of the rear panel (<NUM>), penetrating the rear panel (<NUM>), the first steam nozzle (<NUM>) being configured to spray steam upward obliquely to the objects;
a first steam path (<NUM>) located outside the tub (<NUM>) and connected to the first steam nozzle (<NUM>) via an inner space of the door (<NUM>), the first steam path (<NUM>) being configured to supply steam to the first steam nozzle (<NUM>); and
a steam guide (<NUM>) provided at an other surface of the rear panel (<NUM>) and connected between the first steam path (<NUM>) and the first steam nozzle (<NUM>), for changing a direction of the steam path, whereby
the steam guide (<NUM>) is formed in the shape of an L for perpendicularly changing the direction of the first steam path (<NUM>), one side of it being connected to a first nozzle insertion part (<NUM>) of the first steam nozzle (<NUM>) and the other side being bent toward the left side or the right side of the door (<NUM>) and connected to the first steam path (<NUM>), whereby the first nozzle insertion part (<NUM>) is inserted through a steam nozzle insertion hole (<NUM>), provided in the rear panel (<NUM>), to protrude into the inner space (<NUM>) of the door (<NUM>).