Convertible dishwasher

A dishwasher includes a filtration system that can be configured in a chopping or filtration only arrangement. A check valve cover attached to an accumulator is inserted into a main intake of a sump and divides the main intake into a fluid recirculation chamber in communication with a recirculation intake port, and a separate fluid draining chamber in communication with a drain port. When a drain pump is actuated, fluid is pulled from the accumulator through the drain port until pressure within the fluid draining chamber drops below the pressure of the sump and a check valve in the check valve cover is forced open, allowing fluid to be channeled out of the fluid recirculation chamber into the fluid draining chamber. Optionally, a fine filter system can replace the convertible filtration system, whereby the main intake is in fluid communication with both the recirculation intake port and the drain port.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention pertains to the art of dishwashers and, more specifically, to a dishwasher including a sump which can be selectively employed with either a removable filtration system or a chopper pump system.

Description of the Related Art

Currently, there are two main wash systems utilized with dishwashers, i.e., chopper systems and filtration systems. In general, in connection with a chopper system, all soils in the washing fluid are directed to a chopping mechanism where the soils are made small enough to pass through the dishwasher's fluid pump, which distributes soil containing fluid to the spray arms of the dishwasher. At least some amount of this soil containing water is diverted to an accumulator/filter where soils are collected and separated from the water. A water nozzle from the spray arm sprays down onto a screen of the accumulator to keep the screen clean over the life of the product. Although chopper systems perform the function of reducing soil size, they also negatively impact the flow of fluid and load on the motor. This leads to a larger pump motor than would be required if no chopping function was performed. Such a system is also louder than simple filtration units because of the larger motor and the sound of the chopper blade turning in the water. Advantageously, chopper systems are self-cleaning, remaining maintenance free. One example of a chopper system can be seen in U.S. Pat. No. 7,404,864, which is incorporated herein by reference.

In a filtration system, soil that might restrict flow through the spray arm nozzles is captured upstream of a recirculation pump by filters in order to prevent the soil from re-depositing on dishware being washed. The filters are typically set up with multiple filters, including at least one fine filter that allows only small, non-nozzle blocking particles through to the fluid pump. One example of such a system can be seen in U.S. Patent Application Publication No. 2010/0037923, which is incorporated herein by reference. A brief description of the '923 dishwasher will now be discussed with reference toFIGS. 1-3.

In general, a dishwasher2includes a tub5having bottom, side and rear walls8-11, as well as a top wall (not shown). Tub5defines a washing chamber14, which is selectively sealed by a door20including a detergent tray23. Disposed within tub5is a filtration system30including a central main strainer or filter screen36and a secondary strainer39. A heating element44is positioned above bottom wall8. A circulation pump (not shown) directs washing fluid from a sump unit50(seen inFIG. 2) to a fluid distribution manifold indicated at53. In a manner known in the art, fluid distribution manifold53supplies washing fluid to at least a lower wash arm55and a conduit57leading to an upper spray arm (not shown). Fluid distribution manifold53is also in fluid communication with spray manifold assembly59, including a plurality of spray discs62. As depicted inFIGS. 2 and 3, sump unit50generally includes a sump enclosure68and a recessed main intake73having an outlet or recirculation intake port80leading to a circulation pump (not shown). Filter screen36constitutes a first-pass screen filter having a shape that aids in channeling washing fluid across the screen to secondary strainer39. In general, washing fluid flows through a screen portion75of strainer39before entering main intake73and exiting outlet80. Filter screen36is substantially circular and is supported along its outer circumferential edge90by filter support surface83and seals against filter support surface83. Filter screen36includes a main body portion100having an aperture105there through and arm portions108and109which define a central opening112in the form of a slot there between. When assembled, central opening112fits around fluid distribution manifold53and aperture105extends over main intake73. In this example, an additional filter (not shown) located adjacent exiting outlet80works alongside filter39to capture soil particles upstream of a fluid recirculation pump (not shown) in main intake area73, and allows these soil particles to pass through a drain pump intake (not shown) when a drain pump is actuated.

With each type of washing system, there are positive and negative aspects. For instance, as indicated above in discussing the chopper system, a larger motor is generally required in order to drive both the pump and the chopper. With a filtration system, it is common for one or more of the filters to require periodic removal for cleaning by a consumer. In any case, both types of systems are desirable, simply for different reasons. To this end, both systems are commonly found on the market. Given the different requirements for each system, the tub, sump, pump mountings and other structural details are unique to the particular type of system. With this in mind, it would be advantageous to provide an overall dishwasher tub and sump arrangement which could be readily adapted for use with either filtration or chopper-type systems.

SUMMARY OF THE INVENTION

The present invention is directed to a dishwasher having a convertible filtration system for use with a universal sump unit. In general, the removable filtration system is adapted to be utilized in a chopping type dishwasher arrangement or in a filtration only dishwasher arrangement. More specifically, a check valve cover attached to an accumulator is inserted into a recessed main intake of the sump unit such that the check valve cover divides the recessed main intake into a fluid recirculation chamber in communication with a recirculation intake port, and a separate fluid draining chamber in communication with a drain port. During a dishwashing cycle, washing fluid is pumped by a recirculation pump to fluid supply hub attached to a spray arm. A portion of fluid within the fluid supply hub is channeled through a bypass port to a filter chamber of the accumulator, where fine particles are filtered out of fluid exiting the accumulator. Particulates within the filter chamber are channeled into the draining chamber by the check valve cover.

When the filtration system is in a chopping type dishwasher arrangement, fluid from a tub of the dishwasher enters the fluid recirculation chamber through a coarse filter, and is channeled through a chopping assembly before being pumped to the fluid supply hub by the recirculation pump. When in a filtration with accumulator dishwasher arrangement, a substantially cylindrical fine filter is inserted into the recessed main intake between a side wall of the intake and the check valve cover. Fluid entering the fluid recirculation chamber is filtered through the fine filter before being pumped to the fluid supply hub by the recirculation pump. In either configuration, when a drain pump is actuated, fluid, as well as any entrained particles therein, is pulled from the accumulator before fluid is pulled directly from the tub. More specifically, fluid is pulled from the accumulator through the drain port until pressure within the fluid draining chamber drops below the pressure of the sump unit. The low pressure forces a check valve in the check valve cover to open, allowing fluid from the sump unit to be channeled out of the fluid recirculation chamber into the fluid draining chamber below. Washing fluid exits the fluid draining chamber through a drain port and is discharged in a manner known in the art. This design also allows the unit to function as a filtration only unit. When in the filtration only configuration, a cylindrical fine filter is inserted into the recessed main intake without a check valve.

An additional feature of the present invention is the convertible nature of the sump unit. Specifically, a non-chopping or fine filter system can replace the convertible filtration system of the present invention. Thus, when the convertible filtration system is utilized, the drain check cover divides the recessed main intake into a fluid recirculation chamber in communication with the recirculation intake port, and a separate draining chamber in communication with the drain port, and when the fine filter system is utilized, the recessed main intake is simultaneously in communication with both the recirculation intake port and the drain port.

Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of preferred embodiments when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With initial reference toFIG. 4, a dishwasher200is shown including a convertible filtration system202constructed in accordance with the present invention. Filtration system202is adapted to be utilized in a chopping type dishwasher arrangement or in a filtration only dishwasher arrangement, as will be discussed in more detail below. Certain structure of dishwasher200is the same or substantially the same as that of dishwasher2ofFIG. 1, such that like reference numbers correspond to identical parts. Conduit57and spray manifold assembly59are not shown for the sake of simplicity, but it should be understood that various water distribution arrangements could be utilized.

Details of filtration system202of the present invention will now be discussed with reference toFIG. 5. In the embodiment shown, central main strainer36′ includes a main body portion100′ having an aperture105′ and a central opening112′. It should be understood that the central main strainer of the present invention can take many different forms depending on the type of water distribution systems utilized within dishwasher200. For example, if dishwasher200where constructed to include a conduit57and spray manifold assembly59(shown inFIG. 1), then the central main strainer can be in the form of central main strainer36depicted inFIGS. 1 and 2. Regardless of the particular configuration, when assembled, central opening112′ of central main strainer36′ fits over distribution manifold53such that a fluid supply hub206for attachment of spray arm55, and an auxiliary port208for attachment to another fluid conduit (not shown) extend through central opening112′. Filtration system202further includes an accumulator204which attaches to a check valve cover210via a funnel portion211of accumulator204. When assembled, check valve cover210and funnel portion211extend through aperture105′ into recessed main intake73. Preferably, check valve cover210is simply seated in recessed main intake73, but could be secured in position, such as through the use of a clasp arrangement employed to lock the fine strainer39in place in the prior art referenced above. An optional fine filter212, which can also be inserted into recessed main intake73, is provided for use in further filtering washing fluid as will be discussed in more detail below. In general, fine filter212is comprised of a substantially circular fine filter screen having a bottom wall212aand a top wall212bdefining a central opening there through.

Details regarding the function of filtration system202will now be discussed with reference toFIG. 6. In a manner known in the art, during a washing cycle initiated by a user, washing fluid pumped by a recirculation pump213(depicted inFIG. 7) forces washing fluid up through fluid supply hub206to attached spray arm55(shown inFIG. 5), which sprays washing fluid within washing chamber14. Washing fluid may also supply another spray arm or manifold, such as spray arm assembly59depicted inFIG. 1, through auxiliary port208. A bypass port214extends from a main conduit216connected to fluid supply hub206and is friction fit to an inlet port218of an accumulator filter chamber220such that a small percentage of the fluid flowing from recirculation pump213is directed into accumulator204. In the embodiment shown, inlet port218has an initial diameter which is wider than the diameter of bypass port214, but narrows before linking to accumulator filter chamber220, thereby forming a pressure relief venturi portion221.

With this arrangement, during the dishwashing cycle, a portion of washing fluid directed toward fluid supply hub206is diverted through bypass port214to accumulator filter chamber220, with the majority of the washing fluid being forced out of filter chamber220and back into washing chamber14through a fine filter screen222. Although depicted with a reinforcing member223extending up within accumulator filter chamber220, accumulator filter chamber220is preferably defined by a single chamber. In any case, particles of food entrained in the washing fluid are filtered out of the washing fluid exiting through fine filter screen222into tub5, with the particles collecting in filter chamber220. In the preferred embodiment shown, fine filter screen222is in the form of a cover plate having outer flange portions224adapted to snap onto or otherwise engage a mounting portion226of accumulator204. Fine filter screen222is positioned such that lower nozzles (not shown) on wash arm55direct fluid onto fine filter screen222to clean accumulated particles off of fine filter screen222during a washing cycle.

The manner in which washing fluid is channeled to a drainage pump230and recirculation pump213will now be discussed with reference toFIG. 7. In a first embodiment, filtration system202is utilized in a chopping type dishwashing arrangement. In use, washing fluid flowing into sump unit50during the dishwashing cycle will flow by gravity through central main strainer36′ into recessed main intake73. Central main strainer36′ acts as a coarse particle strainer to prevent coarse particles from entering recessed main intake73. However, washing fluid flowing into recessed main intake73may carry fine particles which are carried with the washing fluid into recirculation intake port80to a recirculation pump inlet generally indicated at232and to a chopper assembly233. In a manner known in the art, chopper assembly233macerates particles entrained within washing fluid to be recirculated to fluid supply hub206by recirculation pump213. Various types of chopping mechanisms are known in the art which could be utilized in conjunction with the present invention. See, for example, U.S. Pat. Nos. 7,146,992 and 7,404,864 which are incorporated herein by reference. In one particular preferred embodiment, the chopper assembly233is constructed by a blade rotating on a perforated metal disc, with the perforations being very small, such as in the order of 1-1.2 mm in diameter. In this way, particles flowing into wash arm55from fluid distribution manifold53are small enough such that they do not clog wash arm55or otherwise interfere with the distribution of washing liquid into tub5.

Washing fluid within filter chamber220of accumulator204carries fine particles collected in filter chamber220to funnel portion211and into a bottom portion236of main intake73through drain check cover210. In a preferred embodiment, a tubular inlet portion242of drain check cover210frictionally fits about a tubular outlet244of funnel portion211to removably connect drain check cover210to accumulator204. Funnel portion211and tubular inlet portion242of drain check cover210are arranged radially inward from an upper side wall245of main intake73such that the presence of accumulator204does not significantly impact the fluid capacity of main intake73. Drain check cover210further includes a mounting flange246that extends about the periphery of a bottom mounting portion248and seals against a ledge250extending about the periphery of the bottom portion236of main intake73. With this configuration, drain check over210is fluidly connected to accumulator204, while being disposed in and dividing main intake73into an upper fluid recirculating chamber254in fluid communication with recirculation pump213, and a separate, bottom fluid draining chamber255in communication with drain pump230through a drain port256.

As best seen inFIG. 8, drain check cover210includes a check valve260attached to an inner wall262, with check valve260functioning to seal a fluid inlet264adjacent a trough266when in an un-actuated or sealing position. With this arrangement, when drain pump230is actuated, washing fluid, and any entrained particles therein, are pulled from accumulator204before washing fluid is pulled from sump unit50. More specifically, washing fluid and accumulated particles are pulled from accumulator204through drain port256until pressure within fluid draining chamber255drops below the pressure of sump unit50. The low pressure forces check valve264open, allowing fluids from sump unit50to be channeled by trough266out of fluid recirculation chamber254, through fluid inlet264, and into fluid draining chamber255. Washing fluid exiting fluid draining chamber255via drain port256is discharged from dishwasher200in a manner known in the art.

In a second embodiment, filtration system202is utilized in a filtration only dishwashing arrangement. More specifically, when a filtration with accumulator only dishwashing arrangement is desired, accumulator204and check valve cover210are inserted into recessed main intake73in the manner described above, followed by, or as part of, fine filter212. SeeFIG. 7. Preferably, bottom wall212aof fine filter212mounts or is otherwise secured to check valve cover210, and top wall212bof fine filter212extends to accumulator204or up to filter screen36, such that fluid entering upper fluid recirculation chamber254from tub5is filtered by fine filter212before entering recirculation pump inlet232. In the embodiment shown inFIG. 7, bottom wall212aof fine filter212fits within a filter receiving aperture257within check valve cover210to secure fine filter212to check valve cover210. However, fine filter212could also be made part of check valve cover210. Preferably, accumulator204is configured for easy removal from sump unit50such that fine filter212can be accessed by a user for cleaning. When drain pump230is actuated, washing fluid, along with any entrained particles therein, are pulled from accumulator204before washing fluid is pulled from sump unit50. More specifically, washing fluid is pulled from accumulator204through drain port256until pressure within fluid draining chamber255drops below the pressure of sump unit50. The low pressure forces check valve264open, allowing fluids from fluid recirculation chamber254to be channeled through fluid inlet264, and into fluid draining chamber255. Again, washing fluid exiting fluid draining chamber255via drain port256is discharged from dishwasher200in a manner known in the art.

At this point, it should be recognized that a feature of the present invention is the advantageous convertible nature of dishwasher200. That is, sump unit50establishes a universal sump unit configured to be utilized with the convertible filtration system202described above, as well as with a non-chopping or fine filter system wherein a main intake filter, such as fine filter39ofFIGS. 1 and 2, is utilized. More specifically, during assembly of dishwasher200, a manufacturer can select between the convertible filtration system202described above and the fine filtration system utilizing fine strainer39. When the fine filtration system is selected, fine filter39is inserted into recessed main intake73and performs the function of filtering washing fluid flowing into recessed main intake73from tub5in a manner known in the art. However, when universal sump unit50is utilized with check valve cover210, a closed system is created, separate from the sump, where soils can be accumulated during the washing of dishes. Specifically, drain check cover210divides recessed main intake73into fluid recirculation chamber254in communication with recirculation intake port80and separate draining chamber255in communication with drain port256, and when universal sump unit50is utilized with the fine filtration system, recessed main intake73is simultaneously in communication with both recirculation intake port80and drain port256.

Advantageously, the present invention allows for a single dishwasher tub and sump arrangement to be readily adapted for use with either a chopping type filtration system or a non-chopping filtration system. Thus, a manufacturer or user can select the type of system to be used based on each system's advantages/disadvantages and the particular desires or needs of the user. For example, the chopping type filtration arrangement is self-cleaning and relatively maintenance free, while the non-chopping filtration arrangement can utilize a smaller pump motor and is generally quieter than the chopping type filtration arrangement. Additionally, when utilized, accumulator204reduces the amount of soil re-deposited on dishes. The wash water is therefore cleaner and can be used longer, requiring less water to clean the dishes. Further, accumulator204is positioned such that backwash nozzles (not shown) used to clean accumulator filter screen222are the same nozzles used to clean main filter screen36when accumulator204is not utilized. Thus, manufacturing costs are reduced by providing dishwasher parts that can be utilized in conjunction with the different filtration arrangements discussed above.

Although described with reference to preferred embodiments of the invention, it should be readily understood that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, although dishwasher200is depicted with only a single spray arm55, it should be understood that dishwasher200can include an upper spray arm and even additional spray arms or other fluid distribution systems desired. In fact, the invention can be employed in a dishwasher having a wide range of spray devices, including rotatable spray arms, spray discs, fixed heads and the like. Additionally, when non-chopping filtration is desired, the drain check cover and accumulator arrangement of the invention could be used with filter arrangements other than filter222. In general, the invention is only intended to be limited by the scope of the following claims.