Patent Description:
A dishwasher is a household appliance that removes foreign matter remaining in a tableware by spraying washing water to the tableware. The dishwasher typically includes a tub for providing a washing space, a rack which is provided in the tub and accommodates the tableware, a spraying arm for spraying the washing water into the rack, a sump for storing the washing water, and a pump for supplying washing water stored in the sump to the spraying arm.

Meanwhile, the dishwasher performs cleaning by using heated washing water, or performs cleaning or sterilization of the tableware by supplying steam to the tableware. Conventional dishwashers typically generate hot water or steam by heating washing water stored in the sump through a heater provided inside the sump. In this case, since the heater must be exposed to the inside of the sump and be in contact with the washing water, the water level inside the sump must be controlled so that the heater should not be exposed to prevent overheating of the heater. In addition, since the heat transmission is possible only when the heater is in contact with the washing water, there is a problem that foreign matter adheres to the surface of the heater to deteriorate the heat exchange efficiency and the surface of the heater is corroded to decrease the durability.

To overcome these disadvantages, a dishwasher that installs a heater in a pump has recently been developed. In this case, the heater in the pump heats the washing water to generate hot water or steam. However, there is a problem in that the performance of the pump is deteriorated as the air is introduced through a passage for discharging the steam, or the steam performance is deteriorated as the steam is discharged through a passage through which the washing water flows.

The prior art disclosed in <CIT>, <CIT>, <CIT>, <CIT> relates to various improvements in dishwasher technology, primarily focusing on steam generation, water circulation, and efficiency.

It is an object of the present invention to overcome the above problems. The object is achieved by the features of the subject-matter of the independent claim.

The dependent claims relate to further aspects of the invention.

The present invention has been made in view of the above problems, and provides a pump and a dishwasher that can generate steam and smoothly discharge the steam without deteriorating the performance of the pump.

In accordance with the present invention, a pump includes: a housing; a washing water inlet pipe to receive washing water; a washing water outlet pipe to discharge the washing water; an impeller to transfer the washing water from the washing water inlet pipe to the washing water outlet pipe; a heater to heat the washing water in the housing and generate steam; and a steam discharge pipe coupled to the washing water outlet pipe to discharge the steam generated by the heater.

The steam discharge pipe has a cross-sectional area smaller than a cross-sectional area of the washing water outlet pipe.

A pipe direction of the steam discharge pipe is inclined to an upward direction from a horizontal direction.

The steam discharge pipe is disposed to be orthogonal to the washing water outlet pipe.

The pump further includes a partition wall which divides an internal space of the housing to form a positive pressure chamber and a negative pressure chamber, the impeller is disposed in the positive pressure chamber, wherein the washing water inlet pipe is coupled to the negative pressure chamber of the housing, and the washing water outlet pipe is coupled to the positive pressure chamber of the housing.

The washing water outlet pipe has a stepped portion protruding inward in a portion coupled to the steam discharge pipe.

The stepped portion protrudes inward in an upstream side of a portion of the washing water outlet pipe coupled to the steam discharge pipe.

The stepped portion is formed at an entrance of the steam discharge pipe.

The pump further includes a check valve to close the washing water inlet pipe to prevent the steam generated by the heater from flowing out through the washing water inlet pipe.

In accordance with another aspect of the present invention, a dishwasher includes: a tub; a spraying arm; a steam supply unit to discharge steam into the tub; a sump; and a pump to supply the washing water stored in the sump to the spraying arm and generate steam to supply to the steam supply unit, wherein the pump having a negative pressure chamber coupled to the sump and a positive pressure chamber coupled to the spraying arm, wherein the steam supply unit is coupled to the positive pressure chamber.

The pump includes a partition wall to divide an internal space into the negative pressure chamber and the positive pressure chamber.

The pump includes: a washing water outlet pipe coupled to the positive pressure chamber to discharge the washing water to the spraying arm; and a steam discharge pipe coupled to the washing water outlet pipe and discharges steam to the steam supply unit.

The washing water outlet pipe has an upstream side cross-sectional area smaller than a downstream side cross-sectional area based on a portion where the steam discharge pipe is connected.

The pump includes: a washing water inlet pipe coupled to the negative pressure chamber to introduce the washing water from the sump; and a check valve to close the washing water inlet pipe to prevent steam generated by the heater from flowing out through the washing water inlet pipe.

The objects, features and advantages of the present invention will be more apparent from the following detailed description in conjunction with the accompanying drawings, in which:.

Exemplary embodiments of the present invention are described with reference to the accompanying drawings in detail. The same reference numbers are used throughout the drawings to refer to the same or like parts. Detailed descriptions of well-known functions and structures incorporated herein may be omitted to avoid obscuring the subject matter of the present invention.

Hereinafter, the present invention will be described with reference to the drawings for explaining a pump and a dishwasher including the same according to embodiments of the present invention.

<FIG> is a schematic cross-sectional view of a dishwasher according to an embodiment of the present invention.

A dishwasher <NUM> according to an embodiment of the present invention may include a cabinet <NUM> forming an outer appearance, a tub <NUM> provided inside the cabinet <NUM> to accommodate a dishware, a plurality of spraying arms <NUM> and <NUM> for spraying washing water into the tub <NUM>, a steam supply unit <NUM> for discharging steam into the tub <NUM>, a sump <NUM> for storing washing water, and a pump <NUM> for supplying the washing water stored in the sump <NUM> to the plurality of spraying arms <NUM> and <NUM> and generating steam to supply to the steam supply unit <NUM>.

A plurality of racks <NUM> and <NUM> for storing dishware may be provided in the tub <NUM>. The plurality of racks <NUM> and <NUM> may include an upper rack <NUM> provided in an upper area of the tub <NUM> and a lower rack <NUM> provided in a lower area of the tub <NUM>.

The tub <NUM> may be opened and closed by a door <NUM> provided on one side of the cabinet. A user may take out the plurality of racks <NUM> and <NUM> from the tub <NUM> after opening the door <NUM>.

The plurality of spraying arms <NUM> and <NUM> may include an upper arm <NUM> for spraying washing water to the upper rack <NUM> and a lower arm <NUM> for spraying washing water to the lower rack <NUM>. The washing water sprayed from the plurality of spraying arms <NUM> and <NUM> may be collected into the sump <NUM>.

The sump <NUM> may be provided in a lower portion of the tub <NUM> to store washing water. A sump cover <NUM> may be disposed in an upper side of the sump <NUM>. The sump cover <NUM> may be provided with a recovery hole <NUM> so that washing water in the tub <NUM> can pass through the recovery hole <NUM> and flow into the sump <NUM>.

The sump <NUM> may be coupled to an external water source through a water supply channel <NUM>. The water supply channel <NUM> may be opened and closed by a water supply valve <NUM>. The washing water stored in the sump <NUM> may be discharged to the outside of the cabinet <NUM> through a drainage pipe <NUM> and a drainage pump <NUM>.

The washing water stored in the sump <NUM> may be supplied to the plurality of spraying arms <NUM> and <NUM> through the pump <NUM> and a washing water supply unit <NUM>. The washing water supply unit <NUM> may include a main connection pipe <NUM> coupled to the pump <NUM>, an upper portion connection pipe <NUM> connecting the main connection pipe <NUM> and the upper arm <NUM>, and a lower portion connection pipe <NUM> connecting the main connection pipe <NUM> and the lower arm <NUM>.

The upper portion connection pipe <NUM> and the lower portion connection pipe <NUM> may be branched from the main connection pipe <NUM>, and a switching valve <NUM> for controlling the opening and closing of the upper portion connection pipe <NUM> and/or the lower portion connection pipe <NUM> may be provided in a branch point of the upper portion connection pipe <NUM> and the lower portion connection pipe <NUM>.

The sump <NUM> may be coupled to the pump <NUM> and a supply pipe <NUM>. The supply pipe <NUM> may guide the washing water in the sump <NUM> to the pump <NUM>.

The steam supply unit <NUM> may discharge the steam into the tub <NUM>. The steam discharged from the steam supply unit <NUM> may rise and act on the tableware housed in the plurality of racks <NUM> and <NUM>. The steam supply unit <NUM> may include a steam nozzle <NUM> disposed in the tub <NUM> to discharge steam and a steam supply pipe <NUM> connecting the steam nozzle <NUM> and the pump <NUM>.

The pump <NUM> may transmit the washing water stored in the sump <NUM> to the washing water supply unit <NUM>. The pump <NUM> may heat the washing water transmitted to the washing water supply unit <NUM>. The pump <NUM> may suck the washing water stored in the sump <NUM> and supply to the plurality of spraying arms <NUM> and <NUM> through the washing water supply unit <NUM>.

The pump <NUM> may generate steam and supply it to the steam supply unit <NUM>. The pump <NUM> may generate steam by heating the washing water stored in the pump <NUM> without transmitting the washing water. The steam generated in the pump <NUM> may be discharged into the tub <NUM> through the steam supply unit <NUM>.

The pump <NUM> will be described in detail with reference to <FIG> and following drawings.

<FIG> is an exploded perspective view of a pump according to an embodiment of the present invention, and <FIG> is a schematic cross-sectional view of a pump according to an embodiment of the present invention.

The pump <NUM> according to an embodiment of the present invention may include a housing <NUM> having a cylindrical shape which is fixed inside the cabinet <NUM>, a washing water inlet pipe <NUM> which is coupled to the housing <NUM> and into which the washing water flows, a washing water outlet pipe <NUM> which is coupled to the housing <NUM> and discharges the washing water, an impeller <NUM> which is disposed inside the housing <NUM> to transfer the washing water from the washing water inlet pipe <NUM> to the washing water outlet pipe <NUM>, a heater <NUM> coupled to the housing <NUM> and heats the washing water inside the housing <NUM> to generate steam, and a steam discharge pipe <NUM> which is coupled to the washing water outlet pipe <NUM> and discharges the steam generated by the heater <NUM>.

The housing <NUM> may be formed in a cylindrical shape having open top and bottom. A housing cover <NUM> may be coupled to the upper end of the housing <NUM>, and the heater <NUM> may be coupled to the lower end thereof. The housing cover <NUM> may cover the upper portion of the housing <NUM>, and the housing cover <NUM> may be provided with a motor <NUM> for generating a rotational force to rotate the impeller <NUM>.

A partition wall <NUM> may be disposed inside the housing <NUM>. The partition wall <NUM> may divide an internal space of the housing <NUM> into upper and lower portions. The partition wall <NUM> may form a negative pressure chamber C1 and a positive pressure chamber C2 inside the housing <NUM>. The negative pressure chamber C1 may be a place where a negative pressure is generated by the rotation of the impeller <NUM> and the positive pressure chamber C2 may be a place where a positive pressure is generated by the rotation of the impeller <NUM>. The negative pressure chamber C1 may be coupled to the sump <NUM> through the supply pipe <NUM> and the washing water inlet pipe <NUM>. The positive pressure chamber C2 may be coupled to the plurality of spraying arms <NUM>, <NUM> through the washing water outlet pipe <NUM> and the washing water supply unit <NUM>.

The partition wall <NUM> may be provided with a communication hole <NUM> for communicating the negative pressure chamber C1 and the positive pressure chamber C2. The surface of the partition wall <NUM> in the positive pressure chamber C2 side may be formed in a volute.

The impeller <NUM> may be rotated by the motor <NUM> to discharge the water in the housing <NUM> to the outside. The impeller <NUM> may be rotatably disposed in the positive pressure chamber C2. The impeller <NUM> may transfer the washing water introduced from the negative pressure chamber C1 into the positive pressure chamber C2 through the communication hole <NUM> to the washing water outlet pipe <NUM>.

The heater <NUM> may be coupled to the lower end of the housing <NUM> to form a bottom surface of the housing <NUM>. The heater <NUM> may heat the washing water flowing inside the housing <NUM> when the impeller <NUM> rotates. The heater <NUM> may generate steam by heating the washing water in the housing <NUM> when the impeller <NUM> stops.

The washing water inlet pipe <NUM> may be coupled to the negative pressure chamber C1 side of the housing <NUM>. The washing water inlet pipe <NUM> may be coupled to the supply pipe <NUM> and the washing water of the sump <NUM> may flow into the negative pressure chamber C1. The washing water inlet pipe <NUM> may be disposed to protrude outward from the lower side wall of the housing <NUM>. The washing water inlet pipe <NUM> may be arranged in such a manner that a pipe direction is horizontal, so that the washing water flows in the horizontal direction. A check valve <NUM> for opening and closing the washing water inlet pipe <NUM> is disposed in the washing water inlet pipe <NUM>. Details of the check valve <NUM> will be described later with reference to <FIG>.

The washing water outlet pipe <NUM> may be coupled to the positive pressure chamber C2 side of the housing <NUM>. The washing water outlet pipe <NUM> may be coupled to the connection pipe <NUM> of the washing water supply unit <NUM> so that the washing water of the positive pressure chamber C2 flows out to the connection pipe <NUM>. The washing water outlet pipe <NUM> may be arranged to protrude outward from the upper side wall of the housing <NUM>. The washing water outlet pipe <NUM> may be arranged in such a manner that a pipe direction is horizontal, so that the washing water flows in the horizontal direction.

The steam discharge pipe <NUM> is coupled to the positive pressure chamber C2 side of the housing <NUM>. The steam discharge pipe <NUM> may be disposed in various locations of the housing <NUM> so as to connect the positive pressure chamber C2 of the housing <NUM> and the steam supply unit <NUM>. In the present embodiment, the steam discharge pipe <NUM> is coupled to the washing water outlet pipe <NUM>. The steam discharge pipe <NUM> may discharge the steam generated in the housing <NUM> by the heater <NUM> to the steam supply unit <NUM>. The steam supply unit <NUM> may be coupled to the positive pressure chamber C2 through the steam discharge pipe <NUM>.

<FIG> is a perspective view of a portion of a pump according to an embodiment of the present invention, <FIG> is a cross-sectional view taken along line A-A of <FIG>, <FIG> is a cross-sectional view taken along line B-B in <FIG>, and <FIG> is an experimental result of washing water outflow of a pump according to an embodiment of the present invention.

The cross sectional area of the steam discharge pipe <NUM> may be smaller than the cross sectional area of the washing water outlet pipe <NUM>. The cross sectional area of the steam discharge pipe <NUM> may be formed to be smaller than the cross sectional area of the washing water outlet pipe <NUM> to minimize the loss of washing water into the steam discharge pipe <NUM>.

The steam discharge pipe <NUM> may be arranged in such a manner that the pipe direction C1 is inclined to the upward direction from the horizontal direction. As shown in <FIG>, the pipe direction C1 of the steam discharge pipe <NUM> may have an included angle i between the horizontal direction and an acute angle. Since the steam in the housing <NUM> flows in a direction opposite to the direction of gravity, the pipe direction C1 of the steam discharge pipe <NUM> may be inclined upward so that the loss of steam from the horizontal washing water outlet pipe <NUM> having a horizontal pipe direction C2 to the washing water supply unit <NUM> can be minimized.

The steam discharge pipe <NUM> may be arranged to be orthogonal to the washing water outlet pipe <NUM>. That is, the steam discharge pipe <NUM> and the washing water outlet pipe <NUM> may be arranged in a "T" shape. As shown in <FIG>, the pipe direction C1 of the steam discharge pipe <NUM> may be disposed to be perpendicular to the pipe direction C2 of the washing water outlet pipe <NUM>, so that the loss of the washing water to the steam discharge pipe <NUM> can be minimized and the loss of steam to the washing water supply unit <NUM> can be minimized.

Referring to <FIG>, an upstream side cross-sectional area of the washing water outlet pipe <NUM> may be smaller than a downstream side cross-sectional area based on a portion where the steam discharge pipe <NUM> is connected. The above-described division between the upstream side and the downstream side may be based on the flow direction of the washing water.

The washing water outlet pipe <NUM> may be formed with a stepped portion <NUM> in which an upstream side, based on the flow direction of the washing water, in a portion where the steam discharge pipe <NUM> is connected protrudes inward. The stepped portion <NUM> may be formed at an entrance of the steam discharge pipe <NUM> based on the steam flow direction. The stepped portion <NUM> may allow the washing water flowing in the washing water outlet pipe <NUM> to pass by the steam discharge pipe <NUM> without being expelled due to inertia.

<FIG> shows a velocity distribution of the washing water when the stepped portion <NUM> does not exist, and <FIG> shows a velocity distribution of the washing water when the stepped portion <NUM> exists. In <FIG>, the red color indicates a faster washing water speed, and the blue color indicates a slower washing water speed. Based on the result of the experiment, when the stepped portion <NUM> exists, the positive pressure of the steam discharge pipe <NUM> may be reduced, and the loss of the washing water to the steam discharge pipe <NUM> may be minimized.

<FIG> is a partial exploded perspective view of a pump according to an embodiment of the present invention, <FIG> is a perspective view of a check valve of a pump according to an embodiment of the present invention, and <FIG> is an operational example of a check valve of a pump according to an embodiment of the present invention.

The check valve <NUM> may open and close the washing water inlet pipe <NUM> so that the steam which is generated inside the housing <NUM> by the heater <NUM> may not flow out through the washing water inlet pipe <NUM>. The check valve <NUM> may be opened when the impeller <NUM> rotates and may be closed when the impeller <NUM> stops. That is, the check valve <NUM> may be opened when the washing water flows and may be closed when the washing water does not flow. The check valve <NUM> may close the washing water inlet pipe <NUM> during the steam generation of the heater <NUM> so that the steam generated inside the housing <NUM> may not flow out to the supply pipe <NUM> through the washing water inlet pipe <NUM> from the negative pressure chamber C1.

The check valve <NUM> may include a valve body <NUM> having a circular segment shape, and a valve fixture <NUM> which is coupled so that the valve body <NUM> can be rotatable.

The valve body <NUM> may be rotated to open and close the washing water inlet pipe <NUM>. The valve body <NUM> may rotate toward the negative pressure chamber C1 side when opened. The valve body <NUM> may be provided with a valve hole <NUM> through which a part of the valve fixture <NUM> is passed.

The valve body <NUM> may be formed in a circular segment shape so as not to completely block the washwater inlet pipe <NUM>. The valve body <NUM> may be formed in a circular shape having a cut lower portion so that a part of the lower portion of the washing water inlet pipe <NUM> is opened when closed. It is required that the washing water in the pump <NUM> should be drained when the drain pump <NUM> operates. When the drain pump <NUM> operates, the washing water in the pump <NUM> may flow into the supply pipe <NUM> through a gap between the valve body <NUM> and the washing water inlet pipe <NUM> and may be discharged to the outside through the sump <NUM> and the drainage pipe <NUM>.

The valve fixture <NUM> may be coupled so that the valve body <NUM> can rotate. The valve fixture <NUM> may be coupled to the washing water inlet pipe <NUM> so that the valve body <NUM> can be arranged to be rotatable for the washing water inlet pipe <NUM>. The valve fixture <NUM> may be provided with a ring-shaped outlet end connecting unit <NUM> and a hinge unit <NUM> penetrating the valve hole <NUM>.

The outlet end connecting unit <NUM> may be formed in a ring shape and may be coupled to a distal end of the washing water inlet pipe <NUM>. The circumference of the outlet end connecting unit <NUM> may be in contact with the valve body <NUM>. The hinge unit <NUM> may pass through the valve hole <NUM> and may be coupled to the washing water inlet pipe <NUM>.

When the washing water is introduced through the supply pipe <NUM> during rotation of the impeller <NUM>, the valve body <NUM> may be rotated by the flow pressure of the washing water to open the washing water inlet pipe <NUM>. When the impeller <NUM> is stopped, the valve body <NUM> may be in contact with the outlet end connecting unit <NUM> to close the washing water inlet pipe <NUM>.

The operation of the pump and the dishwasher according to the present invention will be described as follows.

When the water supply valve <NUM> is opened, washing water may be supplied from an external water supply source through the water supply pipe <NUM> and be stored in the sump <NUM>. When the motor <NUM> rotates the impeller <NUM>, the washing water stored in the sump <NUM> may flow into the washing water inlet pipe <NUM> through the supply pipe <NUM>. At this time, the check valve <NUM> may be rotated by the flow pressure of the washing water to open the washing water inlet pipe <NUM>. The washing water flowed into the washing water inlet pipe <NUM> may flow into the negative pressure chamber C1 inside the housing <NUM>. The washing water in the negative pressure chamber C1 may flow into the positive pressure chamber C2 through the communication hole <NUM> and then flow into the washing water outlet pipe <NUM> by the rotation of the impeller <NUM>. At this time, the heater <NUM> may heat the washing water flowed into the housing <NUM>. The washing water flowed into the washing water outlet pipe <NUM> may partially flow to the steam discharge pipe <NUM> but mostly may flow to the washing water supply unit <NUM>. The washing water flowed into the washing water supply unit <NUM> may be sprayed through the upper arm <NUM> and/or the lower arm <NUM> depending on the operation of the switching valve <NUM>. The washing water sprayed through the upper arm <NUM> and/or the lower arm <NUM> may be recovered to the sump <NUM>.

Meanwhile, when the heater <NUM> operates but the motor <NUM> does not rotate the impeller <NUM>, the washing water in the housing <NUM> may be heated to generate steam. The steam generated in the housing <NUM> may flow into the washing water outlet pipe <NUM> and then flow to the steam discharge pipe <NUM>. The steam flowing in the washing water outlet pipe <NUM> can be partially flow to the washing water supply unit <NUM> but mostly flow to the steam discharge pipe <NUM>.

The steam flowed into the steam discharge pipe <NUM> may be discharged into the tub <NUM> through the steam supply unit <NUM>.

According to the pump of the present invention and the dishwasher including the same, one or more of the following effects can be obtained.

First, the steam discharge pipe is coupled to the positive pressure chamber of the pump to prevent the air in the tub from flowing into the pump and to secure the flow rate of the pump.

Second, the steam discharge pipe is coupled to the washing water outlet pipe to minimize the flowing of the steam generated in the pump to the spraying arm side, thereby improving the steam performance.

Third, even when the steam discharge pipe is coupled to the washing water outlet pipe, the pump performance is improved by minimizing the discharge of the washing water to the steam discharge pipe.

Fourth, the steam generated in the pump is prevented from flowing out to the sump side by the check valve disposed in the washing water inlet pipe, thereby improving the steam performance.

Claim 1:
A dishwasher (<NUM>) comprising:
a tub (<NUM>);
a spray arm (<NUM>, <NUM>) configured to spray washing water into the tub (<NUM>);
a steam supply unit (<NUM>) configured to discharge steam into the tub (<NUM>);
a sump (<NUM>) configured to store washing water; and
a pump (<NUM>) that is configured to supply washing water stored in the sump (<NUM>) to the spray arm (<NUM>, <NUM>), that is configured to generate steam, and that is configured to supply steam to the steam supply unit (<NUM>),
wherein the pump (<NUM>) comprises:
a housing (<NUM>);
a washing water inlet pipe (<NUM>) coupled to the housing (<NUM>) to receive washing water;
a washing water outlet pipe (<NUM>) coupled to the housing to discharge the washing water;
an impeller (<NUM>) disposed in the housing (<NUM>) to transfer the washing water from the washing water inlet pipe (<NUM>) to the washing water outlet pipe (<NUM>);
a heater (<NUM>) coupled to the housing (<NUM>) to heat the washing water in the housing (<NUM>) and generate steam; and characterized by:
a steam discharge pipe (<NUM>) coupled to the washing water outlet pipe (<NUM>) to discharge the steam generated by the heater (<NUM>), and
wherein the pump comprises a partition wall (<NUM>) dividing the inside of the housing (<NUM>) into an upper portion and a lower portion, and having a communication hole (<NUM>) communicating the upper portion and the lower portion thereof at one side thereof,
wherein the impeller (<NUM>) is disposed in the upper portion of the housing (<NUM>).