US20160353966A1

US20160353966A1 - Automatic dishwasher

Info

Publication number: US20160353966A1
Application number: US14/731,511
Authority: US
Inventors: Rodney M. Welch
Original assignee: Whirlpool Corp
Current assignee: Whirlpool Corp
Priority date: 2015-06-05
Filing date: 2015-06-05
Publication date: 2016-12-08
Also published as: EP3100663A1

Abstract

An automatic dishwasher with a tub that at least partially defines a treating chamber, a liquid spraying system that supplies liquid to the treating chamber, and a pump assembly fluidly coupling the treating chamber to the liquid spraying system, a portion of which is located above a bottom wall of the tub.

Description

BACKGROUND OF THE INVENTION

A dishwashing machine is a domestic appliance into which dishes and other cooking and eating wares (e.g., plates, bowls, glasses, flatware, pots, pans, bowls, etc.) are placed to be washed. A dishwashing machine includes a cabinet housing a tub with a treating chamber for washing dishes. The tub includes a sump at its lowest point that collects the liquid supplied to the treating chamber for washing dishes. A sump unit including a pump assembly can be provided for recirculating and draining liquid from the sump. The pump assembly must be below the sump so that wash liquid in the sump can be gravity-fed into the pump assembly. The dimensions of the tub must therefore allow for the pump assembly, which may include at least one pump driven by a motor, to be accommodated between the bottom of the tub and the bottom of the cabinet.
Gaskets are often used at the sump unit to incorporate details of the recirculation and draining systems of the dishwasher without having to include those details in the bottom of the tub itself. The dimensions of the tub must therefore allow for the gasket, in addition to the pump assembly.

SUMMARY OF THE INVENTION

In one aspect an embodiment of the invention relates to an automatic dishwasher for washing dishes according to a cycle of operation, the dishwasher having a tub at least partially defining a treating chamber and having a bottom wall, a liquid spraying system supplying liquid to the treating chamber, and a pump assembly comprising a pump fluidly coupling the treating chamber to the liquid spraying system and a motor drivingly coupled to the pump, wherein at least a portion of the pump and at least a portion of the motor are located above the bottom wall of the tub.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic view of an example automatic dishwasher in accordance with one embodiment of the invention.

FIG. 2 is a schematic of an example control system for the example dishwasher of FIG. 1.

FIG. 3 is a perspective view of a detailed embodiment of the bottom wall and a portion of the recirculation system for a dishwasher.

FIG. 4 is an exploded view of a sump unit of the recirculation system from FIG. 3.

FIG. 5 is a cross-sectional view through line V-V of FIG. 3.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific exemplary embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. For example, while the present invention is described in terms of a conventional dishwashing unit, it could also be implemented in other types of dishwashing units, such as in-sink dishwashers or drawer-type dishwashers.
FIG. 1 is a schematic view of an example automatic dishwasher 10 in accordance with one embodiment of the invention. The dishwasher 10 can treat dishes according to an automatic cycle of operation. Depending on whether the dishwasher 10 is a stand-alone or built-in, the dishwasher includes a cabinet 12 that may be a chassis/frame with or without panels attached, respectively. The dishwasher 10 shares many features of a conventional automatic dishwasher, which will not be described in detail herein except as necessary for a complete understanding of the invention. An open-faced tub 14 is within the cabinet 12 and may at least partially define a treating chamber 16, having an open face, for washing dishes.
A closure element, such as a door assembly 18, may be movably mounted to the dishwasher 10 for movement between opened and closed positions to selectively open and close the treating chamber access opening defined by the open face of the tub 14. Thus, the door assembly 18 provides accessibility to the treating chamber 16 for the loading and unloading of dishes or other washable items. It should be appreciated that the door assembly 18 may be secured to the lower front edge of the cabinet 12 or to the lower front edge of the tub 14 via a hinge assembly (not shown) configured to pivot the door assembly 18. When the door assembly 18 is closed, user access to the treating chamber 16 may be prevented, whereas user access to the treating chamber 16 may be permitted when the door assembly 18 is open. Alternatively, the closure element may be slidable relative to the cabinet 12, such as in a drawer-type dishwasher, wherein the access opening for the treating chamber 16 is formed by an open-top tub. Other configurations of the closure element relative to the cabinet 12 and the tub 14 are also within the scope of the invention.
The tub 14 includes a bottom wall 20 and a top wall 22, with a rear wall 24 joining the bottom and top walls 20, 22, and two side walls 26 joining the bottom and top walls 20, 22 and extending from the rear wall 24 toward the open face of the tub 14. When the door assembly 18 is closed, the door assembly 18 effectively forms a front wall of the tub 14 to enclose the treating chamber 16.
Dish holders, illustrated in the form of upper, middle, and lower dish racks 28, 30, 32, may be located within the treating chamber 16 and receive dishes for treatment, such as washing. The upper, middle, and lower racks 28, 30, 32 are typically mounted for slidable movement in and out of the treating chamber 16 for ease of loading and unloading. Other dish holders may be provided, such as a silverware basket, separate from or combined with the upper, middle, and lower racks 28, 30, 32. As used in this description, the term “dish(es)” is intended to be generic to any item, single or plural, that may be treated in the dishwasher 10, including, without limitation, dishes, plates, pots, bowls, pans, glassware, silverware, or any other washable item.
A spray system may be provided for spraying liquid in the treating chamber 16 and may be provided in the form of, for example, an upper spray assembly 34, a middle spray assembly 36, and a lower spray assembly 38. The upper spray assembly 34, the middle spray assembly 36, and the lower spray assembly 38 are located, respectively, beneath the upper rack 28, beneath the middle rack 30, and beneath the lower rack 32 and are illustrated as rotating spray arms by example but are not limited to such positions and sprayer type. The spray system may further include an additional spray assembly 40. For example, a distribution header or spray manifold may be located at the rear of the tub 14 at any vertical position. An exemplary spray manifold is set forth in detail in U.S. Pat. No. 7,594,513, issued Sep. 29, 2009, and titled “Multiple Wash Zone Dishwasher,” which is incorporated herein by reference in its entirety. The illustrated additional spray assembly 40 is illustrated as being located adjacent the lower dish rack 32 along the rear wall 24 of the treating chamber 16.
A recirculation system may be provided for recirculating liquid from the treating chamber 16 to the spray system. The recirculation system may include a sump 42 and a pump assembly 44. The sump 42 collects the liquid sprayed in the treating chamber 16 and may be formed by a sloped or recessed portion of the bottom wall 20 of the tub 14, or may be separate from the bottom wall 20. The pump assembly 44 may include a recirculation pump 46 fluidly coupling the treating chamber 16 to the liquid spraying system and a motor 48 drivingly coupled to the recirculation pump 46. The recirculation pump 46 and motor 48 may be enclosed within a housing 50 having a pump chamber 52 and a motor chamber 54, respectively. The recirculation pump 46 includes an impeller 56 within the pump chamber 52 in fluid communication with the sump 42 via an inlet 58. The lower portion of the housing 50 defining the pump chamber 52 may define a portion of the sump 42 or a remote sump that is coupled to the treating chamber 16 to collect liquid and soil particles via the inlet 58.
During a wash or recirculation cycle, the impeller 56, driven by the motor 48, may draw liquid from the sump 42 through the inlet 58, and the liquid may be simultaneously or selectively pumped through a supply conduit 60 to each of the spray assemblies 34, 36, 38, 40 for selective spraying. A diverter 62 may be provided within a portion of the supply conduit 60 for selectively controlling the supply of liquid to one or more of the spray assemblies 34, 36, 38, 40 at a time. As such, downstream of the diverter, the supply conduit 60 may branch into multiple conduits, each supplying at least one of the spray assemblies 34, 36, 38, 40. While not shown, a liquid supply system may include a water supply conduit coupled with a household water supply for supplying water to the treating chamber 16.
A filter assembly 64 may be provided between the sump 42 and impeller 56 for allowing soils of only a predetermined size into the impeller 56. In some embodiments, the filter assembly 64 may include a rotatable filter provided within the pump chamber 52 and driven by the motor 48 for rotation with the impeller 56. In other embodiments, the filter assembly 64 may be non-rotatable. Other apparatus for filtering the wash liquid may also be provided in addition to or instead of the filter assembly 64. In one non-limiting example, a coarse screen filter 66 may be provided at the bottom wall 20 of the tub 14 to prevent large objects or soils from entering the sump 42.
The rotational axes of the motor 48, impeller 56, and filter assembly 64 are illustrated herein as being horizontally-oriented, with respect to the normal operational position of the dishwasher 10. In other embodiments of the invention, the rotational axes of the motor 48, impeller 56, and/or filter assembly 64 may be vertically-oriented, or at an oblique angle between horizontal and vertical.
The pump assembly 44 may further include a drain pump 68. The drain pump 68 may be driven by a separate motor (not shown) or by the motor 48 for the recirculation pump 46, and may draw liquid from the sump 42, through a sump outlet conduit 70, and pump the liquid out of the dishwasher 10 to a household drain line (not shown) via, for example, a drain conduit 72.
In accordance with one aspect of the present invention, at least a portion of the pump assembly 44 can be located above the bottom wall 20 of the tub 14. By having the pump assembly 44 at least partially above the bottom wall 20, the bottom wall 20 can be lowered closer to the bottom of the cabinet 12 or the floor on which the dishwasher rests. Thus, the distance between the bottom wall 20 and the top wall 22 can be increased, which increases the overall capacity of the tub 14, which may be defined by the volume of the treating chamber 16 or by the number of items that can be received by the dish racks 28, 30, 32. This can also more than offset any capacity potentially lost by the placement of the pump assembly 44 partially above the bottom wall 20, so that an overall capacity increase is still gained in comparison to a dishwasher which positions the entire pump assembly below the bottom wall.
As shown, the bottom wall 20 is sloped downwardly toward the sump 42. In other embodiments, the bottom wall 20 can be flat. The bottom wall 20 can terminate at the junction with the sump 42 and the pump assembly 44, with the sump extending below the bottom wall 20 and at least a portion of the pump assembly 44 extending above the bottom wall 20. In some embodiments the portion of the pump assembly 44 may extend above the entire bottom wall 20, and in other embodiments the portion of the pump assembly 44 may extend above the portion of the bottom wall 20 that meets the pump assembly 44.
As shown, a portion of the recirculation pump 46 and the motor 48 are located above the bottom wall 20 of the tub 14. Portions of the recirculation pump 46 and the motor 48 are also located beneath the bottom wall 20. In addition, the filter assembly 64 is also partially located above the bottom wall 20. The drain pump 68 is shown as located fully beneath the bottom wall 20 of the tub 14, but in other embodiments of the invention the drain pump 68 may also be located at least partially above the bottom wall 20. The diverter 62 is shown as located fully above the bottom wall 20 of the tub 14, but in other embodiments of the invention the diverter 62 may also be located at least partially below the bottom wall 20.
Due to the lower bottom wall 20, the capacity of the tub 14 is larger than that for a standard dishwasher. For example, the capacity of the tub 14 can be sufficient to accommodate least three dish racks 28, 30, 32 instead of the standard two racks. Further, one or more of the dish racks 28, 30, 32 of the dishwasher may be larger than typical racks. For example, in the embodiment shown, the upper rack 28 may be larger than a typical utensil rack found in some dishwashers, while still maintaining a height clearance for the lower racks to accommodate taller items, such as baking sheets and taller bowls. As illustrated, the upper rack 28 can be sized to hold shorter bowls, food storage containers, or glasses. Details of a suitable upper rack 28 can be found in U.S. application Ser. No. 14/620,688, filed Feb. 12, 2015, which is incorporated herein by reference in its entirety.
A control system including a controller 74 may also be included in the dishwasher 10, which may be operably coupled with various components of the dishwasher 10 to implement a cycle of operation. The controller 74 may be located within the door assembly 18 as illustrated, or it may alternatively be located somewhere within the cabinet 12. The controller 74 may also be operably coupled with a control panel or user interface 76 for receiving user-selected inputs and communicating information to the user. The user interface 76 may include operational controls such as dials, lights, switches, and displays enabling a user to input commands, such as a cycle of operation, to the controller 74 and receive information.
As illustrated schematically in FIG. 2, the controller 74 may be coupled with the recirculation pump 46 for recirculating the wash liquid during the cycle of operation, the drain pump 68 for draining liquid from the treating chamber 16, and the diverter 62 for controlling the supply of liquid to one or more of the spray assemblies 34, 36, 38, 40 at a time. The controller 74 may be provided with a memory 78 and a central processing unit (CPU) or processor 80. The memory 78 may be used for storing control software that may be executed by the processor 80 in completing a cycle of operation using the dishwasher 10 and any additional software. For example, the memory 78 may store one or more pre-programmed cycles of operation that may be selected by a user and completed by the dishwasher 10. The controller 74 may also receive input from one or more sensors 82. Non-limiting examples of sensors that may be communicably coupled with the controller 74 include a temperature sensor and turbidity sensor to determine the soil load associated with a selected grouping of dishes, such as the dishes associated with a particular area of the treating chamber 16.
The memory 78 may include volatile memory such as synchronous dynamic random access memory (SDRAM), a dynamic random access memory (DRAM), RAMBUS® dynamic random access memory (RDRAM) and/or any other type of random access memory (RAM) device(s); and/or non-volatile memory such as flash memory(-ies), or flash memory device(s). The processor 80 can be implemented by, for example, one or more Atmel®, Intel®, AMD®, and/or ARM® microprocessors. Of course, other processors from other processor families and/or manufacturers are also appropriate.
The dishwasher 10 may include all of the above exemplary systems, a selection of the above exemplary systems, and/or other systems not listed above as desired. Further, some of the systems may be combined with other systems and/or may share components with other systems. Examples of other systems that the dishwasher may further include are a dispensing system that supplies one or more treating agents or chemistries to the treating chamber 16, heating system for heating the liquid contained in the sump 42, and/or an air supply system that may provide air, which may be heated or not heated, to the treating chamber 16, such as for drying and/or cooling the dishes.
FIGS. 3-5 show a detailed embodiment of a portion of the dishwasher in accordance with the present invention. The detailed embodiment shares many common elements with the schematic embodiment of FIG. 1, and like elements are numbered with corresponding reference numerals. FIG. 3 shows the bottom wall 20 and a portion of the recirculation system for the dishwasher. The bottom wall 20 is sloped downwardly toward a sump unit 84 which mounts the lower spray assembly 38 and includes the sump 42, which is partially visible below the coarse screen filter 66. As shown, the lower spray assembly 38 is mounted to a top portion of the sump unit 84. The diverter 62 is located at a rear portion of the sump unit 84.
FIG. 4 is an exploded view of the sump unit 84 from FIG. 3. The bottom wall 20 includes a bottom surface 144 that is sloped inwardly from a rectilinear edge 146 (which joins which or defines part of, for example, the rear wall 24 and side walls 226 shown in FIG. 1) to a central recessed area 148 that is lower than the bottom surface 144. The bottom surface 144 can effectively define the bottom wall 20, with the central recessed area 148 being considered as “below” the bottom wall 20. The recessed area 148 is provided with an opening 86 for accommodating at least a portion of the sump unit 84. The sump unit 84 includes a sump enclosure 88 having a recessed portion at least partially defining the sump 42. The sump enclosure 88 may house several components of the sump unit 84, including, but not limited to, the pump assembly 44 and a heater assembly 90.
A gasket 92 is provided between the bottom wall 20 and the sump enclosure 88 for sealing the interface between the sump unit 84 and the opening 86 in the bottom wall 20. The gasket 92 can define a perimeter, and the pump assembly 44 can be located within the perimeter defined by the gasket 92. The sump enclosure 88 may have a substantially circular perimeter edge 94, with the gasket 92 sealing the perimeter edge 94 with the bottom wall 20. Other perimeter shapes for the sump enclosure 88 are also possible.
The pump assembly 44 includes the housing 50, shown herein as including a pump housing 96 and a motor housing 98. The pump housing 96 further includes an inlet port 100 in fluid communication with the sump 42, a recirculation outlet port 102 in fluid communication with the diverter 62, and a drain outlet port 104 in fluid communication with the drain pump 68. In the embodiment shown herein, the drain outlet port 104 may be in fluid communication with an inlet 106 to the drain pump 68, shown herein as provided in the sump enclosure 88 via a drain conduit 108. Details of a suitable recirculation pump 46 can be found in U.S. application Ser. No. 14/731,481, filed concurrently herewith under Docket No. SUB-US20080648-US-CIP4, which is incorporated herein by reference in its entirety. Details of a suitable drain pump 68 can be found in U.S. application Ser. No. 14/551,131, filed Nov. 24, 2014, which is incorporated herein by reference in its entirety.
The heater assembly 90 can include a heater 110 for heating wash liquid in the sump 42. A thermostat 112 is operably coupled with the heater 110 and senses the temperature of the wash liquid in the sump 42 and switches the heater 110 on or off as needed to maintain the temperature of the wash liquid at or near a desired setpoint. In some embodiments of the invention, the heater 110 may further heat air for drying dishes as well as the wash liquid in the sump 42. In this case, a fan or blower 114 may be provided as a component of the sump unit 84.
The coarse screen filter 66 is supported along its outer perimeter by a support edge 116 formed between the bottom surface 144 and the recessed area 148 of the bottom wall 20. The coarse screen filter 66 can seal against the support edge 116. The coarse screen filter 66 further includes a recessed portion 118 in its outer perimeter which defines an area for accommodating the sump enclosure 88. The coarse screen filter 66 extends over the sump 42 and inlet port 100 to separate the same from the treating chamber 16 (FIG. 1). The coarse screen filter 66 further keeps large soils and debris away from the heater assembly 90.
In addition to the coarse screen filter 66, a strainer 120 with depending ribs 122 is provided to prevent larger and/or longer objects or soils from entering the inlet port 100. The strainer 120 also reduces turbulence in the wash liquid around the inlet port 100, enabling the recirculation pump 46 to run with less wash liquid.
FIG. 5 is a cross-sectional view through line V-V of FIG. 3. The recirculation pump 46 includes the impeller 56, which is rotated about a horizontal axis within the pump chamber 52, which is defined by the pump housing 96. The impeller 56, driven by the motor 48, draws wash liquid from the sump 42 into the pump chamber 52 through the inlet port 100 and pump the wash liquid out through the recirculation outlet port 102 or to the drain outlet port 104. The impeller 56 and motor 48 may be aligned, with the rotational axes of each being horizontally-oriented. By “horizontally-oriented,” the axes may be parallel or substantially parallel to a surface on which the dishwasher rests, i.e. a normal operational position of the dishwasher.
Wash liquid drawn into the housing can first pass through the filter assembly 64 for allowing particles only of a predetermined size into the pump chamber 52. The filter assembly illustrated includes a rotating filter 124 driven by the recirculation pump 46 and a soil chopper 126, both of which may reside in a filter chamber 128 defined within the pump housing 96. In other embodiments, the filter 124 may be a non-rotating filter, or may be eliminated entirely. The rotational axis of the filter 124 may be aligned with the rotational axes of the impeller 56 and motor 48.
The filter chamber 128 may be functionally part of the sump 42 or may act as a remote sump 130. The inlet port 100 is provided within the sump 42, and may lead into the remote sump 130. The filter chamber 128 leads into the pump chamber 52 housing the impeller 56.
With general reference to FIGS. 3 and 5, in operation, during recirculation the recirculation pump 46 is active, and wash liquid and soil flows through the coarse screen filter 66 and into the inlet port 100 of the pump housing 96. The filter assembly 64 allows soils of only a predetermined side into the pump chamber 52, i.e. soils larger than the predetermined size will not enter the pump chamber 52 and soils of or smaller than the predetermined size will enter the pump chamber 52. The impeller 56 in the pump chamber 52 drives the wash liquid through the recirculation outlet port 102 and to the diverter 62. The diverter 62 supplies the wash liquid to one or more of the sprayers 34, 36, 38, 40 (FIG. 1). All liquid from the recirculation pump 46 may pass through the diverter 62, even liquid supplied to the lower spray assembly 38. During recirculation, the heater 110 may be active to heat wash liquid in the sump 42.
During draining, the drain pump 68 is active, and wash liquid and soil flows through the coarse screen filter 66, into the inlet port 100 of the pump housing 96 and through the drain outlet port 104. Actuation of the drain pump 68 also drains liquid, soils, or other foreign matter within the filter chamber 128 and remote sump 130. During draining or after recirculation, the heater 110 may be active to heat air for drying dishes.
With reference to FIG. 5, as noted above, at least a portion of the pump assembly 44 can be located above the bottom wall 20 of the tub 14. More particularly for the embodiment illustrated, at least a portion of the pump assembly 44 can be located above the gasket 92 sealing the interface between the sump unit 84 and the bottom wall 20.
The gasket 92 includes an upper surface 132, an inner surface 134, an outer surface 136 and a lower surface 138, which together define a generally ring-shaped body, although other shapes for the gasket 92 are possible. The surfaces 132, 134, 136, 138 can be generally planar or contoured as needed to create a seal at the interface between the sump unit 84 and the bottom wall 20. In the illustrated embodiment, the upper surface 132 is generally planar and the outer surface 136 is ribbed. The inner surface 134 of the gasket 92 can define the perimeter of the gasket 92, and the pump assembly 44 can be located within the perimeter defined by the inner surface 134.
The bottom wall 20 and the gasket 92 can define a plane, 140, 142, respectively. In the some embodiments of the invention, the planes 140, 142 defined by the bottom wall 20 and the gasket 92 may be coplanar. In the illustrated embodiment, however, the gasket plane 142 is lower than the bottom wall plane 142. It is noted that both the bottom wall 20 and gasket 92 may have nonplanar portions, and that plane 140, 142 defined by each may be defined by only portion of the bottom wall 20 and gasket 92. For example, the gasket plane 140 can be defined by the upper surface 132 of the gasket 92, as in FIG. 5, or may be defined by another portion of the gasket 92, such as the lower surface 138. The bottom wall plane 142 can be defined by the bottom surface 144of the bottom wall 20, as in FIG. 5, which is sloped; in this case, the plane 142 may be defined as an imaginary two-dimensional surface that passes through the lowest points of the bottom surface 144. In other embodiments of the invention, the planes 140, 142 may not be so limited.
In the embodiment of the invention illustrated, a portion of the recirculation pump 46, including portions of the motor 48, impeller 56, filter 124, and housing 50, can be located above the plane 140 defined by the gasket 92, as well as the plane 142 defined by the bottom wall 20. The diverter 62 can be external of the pump assembly 44, as illustrated. As such, the diverter 62 can be located above or below the bottom wall 20 of the tub 14. Here, the diverter 62 is located above the bottom wall 20, and more particularly above the planes 140, 142. The diverter 62 is further laterally offset from the recirculation pump 46.
As a feature of at least some embodiments of the invention, the entire assembly 44 can be shifted toward the rear wall 24 of the tub 14. This can place the inlet port 100 to the recirculation pump 46 closer to the center of the tub 14, which is beneficial because this minimizes the distance from all directions that wash liquid must travel across the bottom wall 20 of the tub 14 to enter the inlet port 100. As wash liquid can enter the pump 46 more quickly and efficiently, a lower volume of wash liquid is required to keep the inlet port 100 submerged.
There are multiple advantages of the present disclosure arising from the various features of the method, apparatuses, and system described herein. For example, the embodiments of the apparatus described above allow for the tub bottom to be closer to the floor on which the dishwasher rests than was possible with prior dishwasher constructions. In prior dishwasher constructions, for wash liquid to be fed by gravity from the sump to a pump, the pump and its associated motor must be below the sump. This places a constraint on how low the sump can be relative to the floor on which the dishwasher rests. Gasket to a remote or secondary sump that are often present places further constraints on how low the tub can be. Embodiments of the present invention remove this constraint, such that the sump can be lower and the tub larger in order to increase the size of the treating chamber and increase the capacity of the dishwasher.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

What is claimed is:

1. An automatic dishwasher for washing dishes according to a cycle of operation, comprising:

a tub at least partially defining a treating chamber and having a bottom wall;

a liquid spraying system supplying liquid to the treating chamber; and

a pump assembly comprising a pump fluidly coupling the treating chamber to the liquid spraying system and a motor drivingly coupled to the pump;

wherein at least a portion of the pump and at least a portion of the motor are located above the bottom wall of the tub.

2. The automatic dishwasher of claim 1 and further comprising a gasket between the bottom wall of the tub and the pump assembly, wherein the gasket defines a perimeter and the pump assembly is located within the perimeter.

3. The automatic dishwasher of claim 2, wherein the gasket defines a plane, and at least a portion of the pump and at least a portion of the motor are located above the plane defined by the gasket.

4. The automatic dishwasher of claim 1, wherein the pump assembly further comprises a housing enclosing the pump and motor, wherein at least a portion of the housing is located above the bottom wall of the tub.

5. The automatic dishwasher of claim 4, wherein a portion of the housing defines a sump fluidly coupled to the treating chamber for collecting liquid and soil particles.

6. The automatic dishwasher of claim 4 and further comprising a filter located within the housing.

7. The automatic dishwasher of claim 6, wherein at least a portion of the filter is located above the bottom wall of the tub.

8. The automatic dishwasher of claim 6, wherein the filter is a rotating filter driven by the motor.

9. The automatic dishwasher of claim 8, wherein the pump, motor, and filter comprise rotational axes which are horizontally-oriented.

10. The automatic dishwasher of claim 1, wherein the pump and motor comprise rotational axes which are horizontally-oriented.

11. The automatic dishwasher of claim 1, wherein the pump assembly further comprises a filter, and wherein at least a portion of the filter is located above the bottom wall of the tub.

12. The automatic dishwasher of claim 1, wherein the liquid spraying system further comprises:

at least two sprayers spraying liquid within the treating chamber; and

a diverter for selectively controlling the supply of liquid from the pump to the at least two sprayers;

wherein the diverter is external of the pump assembly.

13. The automatic dishwasher of claim 12, wherein the diverter is located above the bottom wall of the tub.

14. The automatic dishwasher of claim 12, wherein the diverter is laterally offset from the pump.

15. The automatic dishwasher of claim 1, wherein the liquid spraying system further comprises at least three rotating spray arms spraying liquid within the treating chamber.

16. The automatic dishwasher of claim 1 and further comprising at least three dish racks provided within the treating chamber for holding dishes.

17. The automatic dishwasher of claim 16 wherein each dish rack has at least one associated sprayer.

18. The automatic dishwasher of claim 17 wherein each dish rack is located above the associated sprayer.