Dishwasher including an inclined grate for filtration

A foreign object protection system for a dishwasher for treating dishes according to a cycle of operation includes a tub, a sump,a recirculation pump;and a foreign object protection system comprising a grate, wherein liquid in the tub collects in the sump and is recirculated by the recirculation pump such that the liquid is drawn through the foreign object grate.

BACKGROUND OF THE INVENTION

Many contemporary dishwashers for use in a typical household include a wash tub for storing utensils during a wash cycle in which the stored utensils are cleaned. A dispensing system may be provided for dispensing a treating chemistry as part of the cycle of operation. A controller may be operably connected with the dispensing system and various other components of the dishwasher to execute the cycle of operation. The cycle of operation may be selected manually by the user or automatically based on one or more conditions determined by the controller. A pump may be provided to distribute liquid in the tub. A foreign object protector may be provided to protect the pump from objects that might harm the pump.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, the disclosure relates to a dishwasher for treating dishes according to at least one automatic cycle of operation, including a tub at least partially defining a treating chamber for receiving dishes for treatment according to the at least one automatic cycle of operation, a sump fluidly coupled to the tub and configured to collect liquid supplied to the tub, a recirculation pump having an inlet fluidly coupled to the sump and an outlet fluidly coupled to the tub to recirculate liquid from the sump to the treating chamber, and a foreign object protection system, disposed in the sump and separating the tub and the outlet, and further including an inclined grate having a first incline, a first valley, a second incline, and a second valley, and wherein the first valley is located downstream of the first incline, the second incline is located downstream of the first valley, and the second valley is located downstream of the second incline, and at least one opening located downstream of the second incline such that a foreign object must travel up and over the first incline and the second incline to reach the at least one opening. Liquid in the tub collects in the sump and may be recirculated by actuating the recirculation pump such that the liquid in the sump may be drawn through the grate and expelled through the outlet to the tub and the grate retains objects that cannot pass through the grate.

In another aspect, the disclosure relates to a dishwasher for treating dishes according to at least one automatic cycle of operation, including a tub at least partially defining a treating chamber for receiving dishes for treatment according to the at least one automatic cycle of operation, a sump fluidly coupled to the tub and configured to collect liquid supplied to the tub, a recirculation pump having an inlet fluidly coupled to the sump and an outlet fluidly coupled to the tub to recirculate liquid from the sump to the treating chamber, and a foreign object protection system comprising an inclined grate having a lower end and an upper end, a first incline, a first valley, a second incline, and a second valley, and wherein the foreign object protection system is disposed in the sump and separating the tub and the outlet, and a plurality of openings provided in the grate, with some of the openings near the lower end being smaller than some of the openings near the upper end. The first valley is located downstream of the first incline, the second incline is located downstream of the first valley, and the second valley is located downstream of the second incline, and wherein liquid in the tub collects in the sump and may be recirculated by actuating the recirculation pump such that the liquid in the sump may be drawn through the grate and expelled through the outlet to the tub and the grate retains objects that cannot pass through the grate.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

InFIG. 1, an automated dishwasher10according to a first embodiment is illustrated. While the illustrated treating appliance is a dishwasher10, other treating appliances are possible, non-limiting examples of which include other types of dishwashing units, such as in-sink dishwashers, multi-tub dishwashers, or drawer-type dishwashers. The dishwasher10shares many features of a conventional automated dishwasher, which will not be described in detail herein except as necessary for a complete understanding of the invention. A chassis12may define an interior of the dishwasher10and may include a frame, with or without panels mounted to the frame. An open-faced tub14may be provided within the chassis12and may at least partially define a treating chamber16, having an open face, for washing dishes. A door assembly18may be movably mounted to the dishwasher10for movement between opened and closed positions to selectively open and close the open face of the tub14. Thus, the door assembly provides accessibility to the treating chamber16for the loading and unloading of dishes or other washable items.

It should be appreciated that the door assembly18may be secured to the lower front edge of the chassis12or to the lower front edge of the tub14via a hinge assembly (not shown) configured to pivot the door assembly18. When the door assembly18is closed, user access to the treating chamber16may be prevented, whereas user access to the treating chamber16may be permitted when the door assembly18is open.

Dish holders, illustrated in the form of upper and lower dish racks26,28, are located within the treating chamber16and receive dishes for washing. The upper and lower racks26,28are typically mounted for slidable movement in and out of the treating chamber16for ease of loading and unloading. Other dish holders may be provided, such as a silverware basket. 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 dishwasher10, including, without limitation; utensils, dishes, plates, pots, bowls, pans, glassware, and silverware.

A spray system is provided for spraying liquid in the treating chamber16and is provided in the form of a first lower spray assembly34, a second lower spray assembly36, a rotating mid-level spray arm assembly38, and/or an upper spray arm assembly40. Upper sprayer40, mid-level rotatable sprayer38and lower rotatable sprayer34are located, respectively, above the upper rack26, beneath the upper rack26, and beneath the lower rack24and are illustrated as rotating spray arms. The second lower spray assembly36is illustrated as being located adjacent the lower dish rack28toward the rear of the treating chamber16. The second lower spray assembly36is illustrated as including a vertically oriented distribution header or spray manifold44. Such a 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.

With references toFIG. 1, a recirculation system is provided for recirculating liquid from the treating chamber16to the spray system. The recirculation system may include a sump30and a pump assembly31. The sump30collects the liquid sprayed in the treating chamber16and may be formed by a sloped or recess portion of a bottom wall of the tub14. The pump assembly31may include a wash pump or recirculation pump33, a drain pump32, a particle chopping assembly (not shown), and a foreign object protection system100(seeFIG. 4). A suitable particle chopping assembly is set forth in detail in U.S. Pat. No. 6,454,872, filed Apr. 4, 2000, and titled “Dishwasher with Food Particle Chopping Assembly,” which is incorporated herein by reference in its entirety. The foreign object protection system100will be discussed in detail below. The drain pump32may draw liquid from the sump30and pump the liquid out of the dishwasher10to a household drain line (not shown). The recirculation pump33may draw liquid from the sump30through the particle chopping assembly (not shown), and the liquid may be simultaneously or selectively pumped through a supply tube42to each of the assemblies34,36,38,40for selective spraying. 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 chamber16.

A heating system including a heater46may be located within the sump30for heating the liquid contained in the sump30.

A controller50may also be included in the dishwasher10, which may be operably coupled with various components of the dishwasher10to implement a cycle of operation. The controller50may be located within the door18as illustrated, or it may alternatively be located somewhere within the chassis12. The controller50may also be operably coupled with a control panel or user interface56for receiving user-selected inputs and communicating information to the user. The user interface56may include operational controls such as dials, lights, switches, and displays enabling a user to input commands, such as a cycle of operation, to the controller50and receive information.

As illustrated schematically inFIG. 2, the controller50may be coupled with the heater46for heating the wash liquid during a cycle of operation, the drain pump32for draining liquid from the treating chamber16, and the recirculation pump33for recirculating the wash liquid during the cycle of operation. The controller50may be provided with a memory52and a central processing unit (CPU)54. The memory52may be used for storing control software that may be executed by the CPU54in completing a cycle of operation using the dishwasher10and any additional software. For example, the memory52may store one or more pre-programmed cycles of operation that may be selected by a user and completed by the dishwasher10. The controller50may also receive input from one or more sensors58. Non-limiting examples of sensors that may be communicably coupled with the controller50include 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.

Particular reference will now be made toFIGS. 3-8in describing further details of the foreign object protection system100.FIG. 3shows the sump30with a foreign object protection system100in place. Turning now toFIG. 4, the sump30includes a housing102having a central recessed area104. The foreign object protection system100fits securely within the central recessed area104such that the foreign object protection system100is positioned on an angle with respect to the sump30. The foreign object protection system100may be held in place by means of a snap or fastener (not shown), but it is not necessary. The housing102may include a downward sloping portion106that leads to the central recessed area104and a washing fluid collection reservoir or pumping chamber108. In accordance with the most preferred form of the invention, pumping chamber108includes a recirculation portion110, including a recirculation inlet111, and a discharge/drain portion112.

Referring toFIG. 5, the example foreign object protection system100may include a top cover120, a first lay130, and a second lay140. In other embodiments of the invention, one or more of these pieces120,130,140may be combined into a single integrated component. The top cover120engages with the first lay130to cover the first lay130. The first lay130may include an inclined bypass wall132spaced apart from a bypass roof122such that water can flow through a bypass opening123between the bypass roof122and the bypass wall132, but objects that are smaller than the bypass opening123are blocked from entering. The first lay130may also include a first lay wall133and at least one first lay opening134in the first lay wall133to allow water and small foreign objects to flow through the first lay130to reach the recirculation pump33. Preferably, the first lay130includes at least one first lay opening134in the first lay wall133. The first lay130engages with the second lay140such that a labyrinth path A′ (seeFIG. 7) is formed. Preferably, labyrinth path A′ is about two millimeters wide or less in size, so items larger than the labyrinth path A′ cannot pass through the labyrinth path A′. The second lay140may be an inclined grate and may include at least one second lay first opening142, at least one second lay second opening144, at least one second lay third opening146, a first valley148, a first incline150, a second valley152, and a second incline154. The slope of the first incline150and the second incline154may vary, such that the first incline150and the second incline154may be vertical walls. The second valley152includes an area lower than the top of the first incline150, such that a concavity is formed. Preferably, the second lay140includes a plurality of second lay first openings142, second lay second openings,144, and second lay third openings146. Preferably, the second lay first openings142are about two millimeters wide or less, the second lay second openings144are about three millimeters wide or less, and the second lay third openings146are about five millimeters wide or less. In other embodiments of the invention, the second lay first openings142may be connected to the second lay second openings144and the second lay third openings146, so as to comprise a single opening of either fixed or variable width.

In operation, and referring now toFIG. 7, the foreign objection protection system100functions like a screen in the sump30. Foreign objects must travel through the foreign object protection system100following path A or A′. Water flows along paths B, which provides resistance for dense items moving through the foreign object protection system100. The top cover120and the first lay130create a labyrinth path A′ for capturing long, skinny items such as toothpicks. Heavy items such as screws will be trapped in the low point created by the intersection of bypass wall132and the first lay wall133, while light items such as pieces of corn can travel up the incline and through the opening123between the bypass cover123and the bypass wall132to the second lay140, and items that are smaller than about 2 millimeters can pass through the labyrinth path A′ and the first lay openings134. Foreign objects must then travel over the first incline150to reach the second valley152and the second lay second openings. Items that are too heavy to travel up the first incline150will be trapped in the first valley148. Lighter, less dense items will travel up the first incline150. Items smaller than the width of the second lay second openings144can pass through the second lay second openings144to the recirculation pump33. Items larger than the width of the second lay second openings144must travel up the second incline154. Items that are too heavy to travel up the second incline154will be trapped in the second valley152. Lighter, less dense items will travel up the second incline154to the second lay third openings146. Items smaller than the second lay third openings146can pass through the second lay third openings146to the recirculation pump33. One example of the relative sizes of the second lay first openings142, second lay second openings144, and second lay third openings146are shown inFIG. 8, although others may be used.

Items that are too large to pass through the second lay third openings146and items that remain trapped in either the first valley148or the second valley152, typically large, light food particles referred to as soils, remain trapped on the second lay140. The pump assembly31(SeeFIG. 4) draws water through the foreign object protection system100whenever the pump is on. When the motor of the pump assembly31is paused, water rushes back into the pumping chamber108. This inrush of water works to lift soft, less dense soils over the first and and second inclines150,154such that the soils may be able to pass through the larger second lay second openings144or second lay third openings146, while dense foreign objects remain trapped in the first valley148. Soils that are too large to pass through the second lay third openings146remain trapped in the second valley152.

When the sump30is drained, the soils dehydrate. They then rehydrate when the sump30fills again. The process of continuous dehydration and rehydration promotes breakdown of the soils better than traditional foreign object protection systems in which soils are contained low in the sump such that they never have the opportunity to dehydrate.

While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation. Reasonable variation and modification are possible within the scope of the forgoing disclosure and drawings without departing from the spirit of the invention which is defined in the appended claims. Further, it will be understood that any features of the above described embodiments may be combined in any manner.