Dish washing machine having a steam generator and an over-pressure prevention feature

Dish washing machine including a steam generator. The dish washing machine also includes a tub that defines a dish washing space therein. A water supply supplies water to the steam generator, and a steam flow conduit guides steam, generated by the steam generator, to the dish washing space. An over-pressure prevention conduit having one end connected to the water supply conduit and the other end connected to either the steam flow conduit or the tub. The over-pressure prevention conduit prevents water in the steam generator from flowing backward into the water conduit and/or the public water supply when a reverse water pressure condition occurs.

This application claims the benefit of Korean Patent Application No. 10-2007-0059317, filed on Jun. 18, 2007, which is hereby incorporated by reference in its entirety as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a dish washing machine that includes a steam generator. More specifically, the present invention relates to a dish washing machine that is capable of preventing over-pressure conditions in the steam generator due, for example, to a clog or blockage in the steam conduit.

2. Discussion of the Related Art

Generally, dish washing machines are well known as devices that automatically wash dishes in the washing compartment of the dish washing machine by spraying wash water, under high pressure, on the dishes, thus, removing foreign matter such as food particles and food residues attached to the surface of the dishes. It is understood that dish washing machine's wash items other than dishes, such as glassware, pots, pans, utensils and the like. However, for ease of discussion, the following disclosure will refer only to dishes.

One important factor associated with dish washing machines is how effectively the machine removes food particles and food residues on or attached to the surface of dishes. In order to improve washing capability, dish washing machines increase the force (i.e., the spray pressure) of the wash water to more effectively remove foreign matter form the surface of the dishes. However, if the spray pressure of the wash water is too high, the dishes may break or otherwise become damaged. Further, when washing dishes with increased spray pressure, the dish washing operation is less efficient because the amount of wash water required increases.

SUMMARY OF THE INVENTION

Accordingly, the following disclosure describes a dish washing machine that obviates one or more of the problems associated with the related art. More specifically, described herein is a dish washing machine that includes a steam generator, where the dish washing machine safely, effectively and efficiently washes dishes without having to employ excessive spray pressure or an excessive amount of wash water. Still further, the following disclosure describes a dish washing machine that is capable of avoiding over-pressure in the steam generator due, for example, to a clog or blockage in the steam generator or the conduits associated therewith.

Various advantages, objects, and features of the invention will be set forth in part in the written description and drawings that follow. Other advantages, objectives and features will become apparent to those having ordinary skill in the art based on the following description and drawings and/or from practicing the invention.

In accordance with one aspect of the present invention, the aforementioned advantages and objects are achieved by a dish washing machine that includes a tub that defines a washing space therein. The dish washing machine also includes a steam generator that generates steam for the washing space during a washing operation, a water supply conduit connected to the steam generator for supplying water to the steam generator, and a steam flow conduit connected to the steam generator which guides the steam generated by the steam generator into the washing space. The dish washing machine further includes a backflow prevention conduit having a first end and a second end, the first end connected to the water supply conduit and the second end connected to the steam flow conduit.

In accordance with another aspect of the present invention, the aforementioned advantages and objects are achieved by a dish washing machine that includes a tub that defines a washing space therein. The dish washing machine also includes a steam generator that generates steam for the washing space during a washing operation, a water supply conduit connected to the steam generator for supplying water to the steam generator, and a steam flow conduit connected to the steam generator which guides the steam generated by the steam generator into the washing space. The dish washing machine further includes a backflow prevention conduit having a first end and a second end, the first end connected to the water supply conduit and the second end connected to the tub.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a perspective view of a dish washing machine according to exemplary embodiments of the present invention. The dish washing machine includes a case1which defines the external appearance of the dish washing machine. Case1is open in front to accommodate a door2. In the exemplary embodiment ofFIG. 1, the door2includes a door grip4, to aid in opening the door2. The door2further includes a steam discharge port6which permits high-temperature air and/or steam to be discharged from inside the dish washing machine. Still further, the door2includes a control panel3.

The control panel3includes, among other things, a power switch5for turning on/off the dish washing machine; a function selection part7, which the user employs to select and initiate a desired dish washing operation; and a display part8for displaying the operational state of the dish washing machine.

FIG. 2is a vertical, sectional view of a dish washing machine in accordance with exemplary embodiments of the present invention. The dish washing machine includes a tub18mounted in the case1. The tub18defines a dish washing compartment or space. A filter17filters the wash water by removing food particles and other waste from the wash water. The filtered wash water is then collected in a sump16, which is mounted at the bottom of the tub18. Filtering and, thereafter, collecting the wash water allows the wash water to be repeatedly re-circulated during a dish washing operation.

Sump16may include a pump (not shown). The pump would be used to pump the filtered wash water back into the washing space. Else, the wash water is discarded through a water drainage conduit23.

The sump16may further include a heater. The heater may be used to heat the wash water collected in the sump16. Heating the wash water generally makes the detergent more effective. Heated water, regardless of the detergent, is known to be more effective in soaking and dissolving food and/or food residue on the dishes.

Still referencingFIG. 2, one or more racks, such as racks11and12are disposed at the upper and lower portions of the dish washing space, respectively. As shown spray arms24,14, and15spray wash water toward the respective racks11and12. A wash water flow conduit19is used for supplying wash water to the upper spray arms14and24.

The dish washing machine, according to exemplary embodiments of the present invention further includes a steam generator100. Steam from the steam generator100, is supplied to the dish washing space. A steam flow conduit110may be used to supply the steam to the dish washing space, as shown. At least one steam nozzle120may be used to introduce the steam into the dish washing space.

In the exemplary embodiment shown inFIG. 2, the steam generator100is mounted below the tub18. As such, the steam is easily supplied to the dish washing space. This is because steam is lighter than air and, therefore, the steam generated by steam generator100tends to rise upward through the steam flow conduit110and into the dish washing space through the steam nozzle120. However, the present invention is not limited to the position of the steam generator100, illustrated inFIG. 2. Alternatively, the steam generator100may be mounted at the side of tub18.

Steam generator100, as shown, includes a case102. Inside case102there is a space for receiving water. Case102also is adapted to receive a heater104, which heats the water in the space formed by case102. The steam generator100also includes a water level sensor106for detecting the level of the water contained therein, and a fuse (not shown) for preventing the heater104from overheating.

The dish washing machine as illustrated inFIG. 2includes a water supply conduit22. This conduit carries water from an external water source to the sump16and eventually to the dish washing space. The dish washing machine also includes a water drainage conduit23for draining dirty wash water after the wash water is used to wash the dishes. Still further, the washing machine includes a tub valve40, which is mounted on the water supply conduit22to control the amount of water supplied through the water supply conduit22.

In the exemplary embodiment ofFIG. 2, water is supplied to the steam generator100through the steam generator water supply conduit111. The steam generator water supply conduit111may be directly connected to an external water supply (not shown) or to the water supply conduit22(connection not shown).

The operation of the dish washing machine, illustrated inFIG. 2, will be described in brief by way of example. First, dishes are placed on racks11and12and door2is closed. The user then makes the desired selection using the function selection part7on control panel7to initiate the operation of the dish washing machine. During the dish washing operation, the operational state of the dish washing machine is displayed on display part8.

The flow sequence of the wash water will now be described. The wash water is sprayed from spray arms14,15and24in the direction of racks11and12. The wash water eventually drops downward through filter17and into the sump16. The pump mounted in the sump16pumps (i.e., recirculates the wash water at a given pressure back into spray arms14,15, and24). When steam is used, the steam generator100supplies steam to the dish washing space through the steam flow conduit110and the steam nozzle120.

As previously stated, filter17removes food debris from the wash water. Consequently, food particles are prevented from blocking the spray arms14,15and24as well as nozzle.

In general, steam improves the washing efficiency and effectiveness of the dish washing machine. The high-temperature and high-humidity characteristics associated with steam also allow moisture to more effectively soak into and loosen food residue on the dishes. Then when high-pressure wash water is sprayed on the dishes, the food residue is more easily removed compared to washing dishes with high-pressure wash water alone.

When the steam generator water supply conduit111is directly connected to a water source (not shown), or indirectly connected to the water source through water supply conduit22, it is important to prevent the water in the steam generator100from flowing backward toward the water source. In general, water is supplied to a home or facility at a relatively constant, predetermined water pressure range. However, if the pressure at the receiving end of the water supply conduit becomes greater than the pressure of the supplied water, it is possible for water to flow into the water supply conduit, backward toward the water supply. An increase in pressure at the receiving end may, for example, result from a blockage (e.g., a clog) in the steam flow conduit110or the steam nozzle120, or for various other reasons. Upon such an occurrence, water in the steam generator100may flow backward into the steam generator water supply conduit111and, eventually, into the public water supply.

Water in the steam generator100can, over time, become contaminated with high concentrations of impurities such as calcium, which may precipitate out of the water in the form of calcium hydrocarbonate (i.e., lime). Thus, the backward flow of water may contaminate clean water in the water supply conduit, which is not desirable. If the backflow pressure is relatively high, the contaminated water may, as previously stated, flow all the back into the public water supply. Consequently, it is desirable, and most countries legally require, that home appliances directly connected to a public water supply, have the ability to prevent water from flowing backward into the water supply conduit, when the reverse water pressure is greater than the supply water pressure.

Solutions preventing backflow when the reverse water pressure is greater than the supply water pressure can significantly increase manufacturing costs. Thus, a more economical solution is desirable. To this end, a dish washing machine according to exemplary embodiments of the present invention further include a backflow prevention conduit130, as illustrated inFIG. 2, having one end connected to the steam generator water supply conduit111and the other end connected to the steam flow conduit110.

As shown, the backflow prevention conduit130joins the water supply side of the steam generator100to the dish washing space (via the steam nozzle120or another opening (not shown). When the reverse water pressure in the steam generator100is greater than the supply water pressure, the relatively higher pressure steam and water in the steam generator100flows through the backflow prevention conduit130and into the dish washing space, because pressure in the dish washing space is less than the pressure of the water flowing into the steam generator100from the steam generator water supply conduit111. As a result, the backward flow of water, from the steam generator100into the steam generator water supply conduit111, is averted. Moreover, the backflow prevention conduit130offers a solution to the reverse water pressure, backflow problem that is relatively inexpensive with respect to manufacturing cost.

FIG. 3is a schematic illustrating a backflow prevention conduit in accordance with one exemplary embodiment of the present invention. In accordance with this exemplary embodiment, a first connection part140connects the backflow prevention conduit130steam generator water supply conduit111. A second connection part150connects the backflow prevention conduit and the steam flow conduit110. The first connection part140and the second connection part150may, for example, be branch type connection conduits, as shown. In this case, the connection between the backflow prevention conduit130and the steam generator water supply conduit111and the connection between the backflow prevention conduit130and the steam flow conduit110may be easily and conveniently accomplished. Specifically, the first connection part140may include a first main conduit141and a first sub-conduit142connected to the side of the first main conduit141. Likewise, the second connection part150may include a second main conduit151and a second sub-conduit152connected to the side of the second main conduit151.

In accordance with this exemplary embodiment, the first main conduit141is connected at one end to a water supply port107of the steam generator100and, at the other end, to the steam generator water supply conduit111. The first sub-conduit142is connected to the backflow prevention conduit130. The second main conduit151is connected at one end to a steam discharge port108of the steam generator100and, at the other end, to the steam flow conduit110. The second sub-conduit152is connected to the backflow prevention conduit130.

Further, in accordance with this exemplary embodiment, and as illustrated inFIG. 3, the first sub-conduit142may diverge upward from the first main conduit141. This prevents the water supplied to the steam generator100from the steam generator water supply conduit111from entering the backflow prevention conduit130. However, if there is backflow due to reverse water pressure, the steam will flow through the water supply port107into the backflow prevention conduit130. This is because steam tends to move upward, whereas water tends to move downward. The steam may eventually flow from the backflow prevention conduit130into the steam flow conduit110.

As shown, the water supply port107is, in this exemplary embodiment, disposed in the upper part of the case101. This facilitates the flow of steam through the water supply port107, into the first connection part140, and then into the backflow prevention conduit130. At the same time, it helps to prevent residual water in the bottom of the steam generator100from flowing into the steam generator water supply conduit111.

The second sub-conduit152preferably diverges downward from the second main conduit151, as shown inFIG. 2. In this case any steam flowing through the steam flow conduit110tends to continue flowing upward toward the dish washing space and not downward, into the backflow prevention conduit130.

Turning our attention back to the first connection part140, the first sub-conduit142is preferably inclined at a predetermined angle in a direction that is the same or substantially the same as the direction of the normal flow of water through the steam generator water supply conduit111and into steam generator100, as shown, for example, inFIG. 2. If, as in this case, the backflow prevention conduit130is connected to the steam generator water supply conduit111via the first sub-conduit142, where the angle formed by the first main conduit141and the first sub-conduit142is relatively small, the air in the backflow prevention conduit130will more easily flow into the steam generator water supply conduit111when an over-pressure condition occurs. Consequently, the backward flow of the water from the steam generator100is further prevented.

If the first sub-conduit142is inclined at an angle in a direction opposite to the normal flow of water, the air in the backflow prevention conduit130will not flow smoothly into the steam generator water supply conduit111when there is reverse water pressure. This is because the direction of the air flow must change such that the air in the backflow prevention conduit130flows to the steam generator water supply conduit111.

FIG. 4is a schematic illustrating a backflow prevention conduit in accordance with another exemplary embodiment of the present invention. The backflow prevention conduit according to this exemplary embodiment is different from the backflow prevention conduit according to the previous exemplary embodiment in that the second connection part160is located in a different position compared to the second connection part150. Otherwise, the components associated with the second connection part160are the same or similar to the components associated with the second connection part150.

With reference toFIG. 4, the second connection part160includes a second main conduit161between the steam flow conduit110and an inlet port118of the steam nozzle120. The second connection part160also includes a second sub-conduit162which connects the second main conduit161to the backflow prevention conduit130. Preferably, the backflow prevention conduit130extends substantially in a vertical direction. In this case, the air in the backflow prevention conduit130will easily flow into the steam generator water supply conduit111, when there is reverse water pressure. In addition, the steam passing through the water supply port107is easily introduced into the nozzle120through the backflow prevention conduit130.

FIG. 5is a schematic illustrating a backflow prevention conduit in accordance with still another exemplary embodiment of the present invention. The backflow prevention conduit130according to this exemplary embodiment differs from the backflow prevention conduits according to the previous exemplary embodiments in that backflow prevention conduit130opens directly into the dish washing space through the wall of tub18. The backflow prevention conduit130may attach to the tub18in any conventional manner. Otherwise, the first connection part140, in accordance with this exemplary embodiment is the same as described above for the two previous exemplary embodiments, as illustrated inFIGS. 3 and 4.

It will be apparent to those skilled in the art that modifications and variations of the present invention are possible without departing from the spirit of and/or scope of the present invention. Thus, it is intended that present invention covers these modifications and variations provided they come within the scope of the appended claims and their equivalence.