DISHWASHER WITH ENERGY RECOVERY SYSTEM

A dishwasher (100) configured to include features for facilitate its cleaning and maintenance and/or to increase its power efficiency. The dishwasher can include a wastewater heat recovery system and/or a steam heat recovery system. The wastewater heat recovery system can include a wastewater heat exchange coil (363) configured to be detachably placed in a wastewater tank (109) of the dishwasher to heat clean water using thermal energy from the wastewater and to facilitate cleaning of itself and the wastewater tank. The wastewater heat recovery system can include a steam heat exchange coil with a clean water inlet, a clean water outlet, and multiple loops each directly connected between the clean water inlet (873) and the clean water outlet (874) to heat clean water using thermal energy from the steam without significantly reducing the pressure in a hydraulic system of the dishwasher.

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Description
TECHNICAL FIELD

This disclosure relates generally to warewashing and more particularly to a washing machine, such as a dishwasher, that includes an energy recovering system to increase energy efficiency by heating clean water using high-temperature wastewater and/or steam.

BACKGROUND

A dishwasher, also referred to as a warewasher or warewashing machine, is a machine for automatically cleaning articles, such as dishes, trays, laboratory equipment, tableware, and kitchenware. A batch of objects to be cleaned (for example, dishes) can be loaded into the dishwasher to be cleaned in a cleaning cycle that include washing and rinsing periods. During the washing period, a washing liquid including water and a detergent is sprayed into the loaded dishwasher to blast the dishes. The washing liquid is then drained before the rinsing period starts. During the rinsing period, a rising liquid including water or a mixture of water and a rinsing aid is sprayed into the loaded dishwasher to remove residue of the washing liquid. After the rinsing period completes with the rinsing liquid being drained, the dishes can optionally be dried using air and/or heat during a drying period. A dishwasher may have various user-selectable settings for each cleaning cycle. The settings may define, for example, time, temperature, and repetition of each of the washing, rinsing, and drying period. The setting may also allow the user to choose which periods to include (e.g., rinsing only, drying only, rinsing and drying, or washing and rinsing without drying).

A common domestic dishwasher is an undercounter unit intended to be installed under a kitchen counter. Other types of dishwasher include industrial or commercial dishwashers for use in restaurants, hotels, and other commercial establishments with food services. High temperature may be used during the washing, rinsing, and drying periods for desired cleaning and/or sanitization effects. As a result, a signification amount of high-temperature wastewater and high-temperature steam may result from operating the dishwasher, particularly when the dishwasher is intended for commercial use that requires cleaning and sanitization of large loads of dishes and/or other objects by repeating the cleaning cycles within limited time.

SUMMARY

A dishwasher configured to include features for facilitate its cleaning and maintenance and/or to increase its power efficiency. The dishwasher can include a wastewater heat recovery system and/or a steam heat recovery system. The wastewater heat recovery system can include a wastewater heat exchange coil configured to be detachably placed in a wastewater tank of the dishwasher to heat clean water using thermal energy from the wastewater and to facilitate cleaning of itself and the wastewater tank. The wastewater heat recovery system can include a steam heat exchange coil with a clean water inlet, a clean water outlet, and multiple loops each directly connected between the clean water inlet and the clean water outlet to heat clean water using thermal energy from the steam without significantly reducing the pressure in a hydraulic system of the dishwasher.

In one example, a dishwasher may be configured to perform cleaning cycles each including a washing period and a rinsing period for cleaning objects. The dishwasher may include a wash chamber, a wash tank, a wastewater tank, and a wastewater heat exchange coil. The wash chamber may be configured to hold the objects. The wash tank may be configured to contain a washing liquid to be sprayed into the wash chamber during the washing period, to receive a returning liquid from the wash chamber to be added to the washing liquid, and to release a portion of the washing liquid when a level of the washing liquid in the wash tank exceeds a threshold level. The wastewater tank may be configured to receive wastewater from the wash tank and to release the received wastewater to a drain pipe. The wastewater includes the portion of the washing liquid released from the wash tank. The wastewater heat exchange coil may be configured to be detachably placed in the wastewater tank and to transfer thermal energy from the wastewater to heat clean water. The wastewater heat exchange coil has a clean water inlet to receive the clean water and a clean water outlet to output the heated clean water.

In one example, a dishwasher may be configured to perform cleaning cycles each including a washing period and a rinsing period for cleaning objects is provided. The dishwasher may include a wash chamber and a steam reduction module. The wash chamber may be configured to hold the objects and to allow the objects to be washed during the washing period and rinsed during the rinsing period. The steam reduction module may include a crossflow fan and a condenser. The fan may be configured to draw steam from the wash chamber and to blow remaining steam out of the dishwasher. The condenser may be placed in the path of the steam between the wash chamber and the fan and configured to condense the steam drawn into the steam reduction module into the remaining steam while heating clean water. The condenser may include a clean water inlet to receive clean water, a clean water outlet to output heated clean water, and a steam heat exchange coil including multiple loops each connected to the clean water inlet directly to receive a portion of the received clean water and connected to the clean water outlet directly to output a portion of the heated clean water.

In one example, a method for operating a dishwasher is provided. The dishwasher is configured to perform cleaning cycles each including a washing period and a rinsing period for cleaning objects. The method may include: receiving a portion of a washing liquid from a wash tank containing the washing liquid; spraying the received portion of the washing liquid into a wash chamber loaded with the objects during the washing period; collecting liquid from the wash chamber and returning the collected liquid into the wash tank to add to the washing liquid; transferring an excessive portion of the washing liquid from the wash tank to a wastewater tank as wastewater, the excessive portion of the washing liquid resulting from a level of the washing liquid in the wash tank exceeding a threshold level; transferring thermal energy from the wastewater to cleaning water flowing through a wastewater heat exchange coil detachably placed in the wastewater tank, to heat the clean water; and transferring the wastewater from the wastewater tank to a drain pipe.

In one example, a method for operating a dishwasher is provided. The dishwasher is configured to perform cleaning cycles each including a washing period and a rinsing period for cleaning objects. The method may include holding the objecting in a wash chamber, washing the objects during the washing period, rinsing the objects during the rinsing period, drawing steam from the wash chamber during each cycle of the cleaning cycles, condensing the steam while heating additional clean water using a steam heat exchange coil including multiple loops each connected to an additional clean water inlet directly to receive a portion of the additional clean water and connected to an additional clean water outlet directly to output a portion of heated additional clean water, and blowing steam remaining from the condensing out of the dishwasher.

In various examples, the subject matter of any one or any combination of the examples discussed above can be implemented in one dishwasher and/or performed for operating one dishwasher.

This Summary is an overview of some of the teachings of the present application and not intended to be an exclusive or exhaustive treatment of the present subject matter. Further details about the present subject matter are found in the detailed description and appended claims. The scope of the present invention is defined by the appended claims and their legal equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate generally, by way of example, various embodiments discussed in the present document. The drawings are for illustrative purposes only and may not be to scale.

FIGS. 1A, 1B, 1C, and 1D are illustrations of an embodiment of a dishwasher, with FIG. 1A showing a front view, FIG. 1B showing a side view with a hood of the dishwasher closed, FIG. 1C showing a side view with the hood open, and FIG. 1D showing a top view

FIG. 2 is an illustration of an embodiment of the dishwasher with examples of accessories.

FIG. 3 is an illustration of an embodiment of a hydraulic system of the dishwasher.

FIG. 4 is a perspective view illustration of an embodiment of component arrangement in a portion of the dishwasher.

FIG. 5 is a cross-sectional view illustration of an embodiment of component arrangement in a portion of the dishwasher.

FIG. 6 is an illustration of an embodiment of a wastewater heat recovery module of the dishwasher.

FIG. 7 is an illustration of an embodiment of portions of a wastewater recycling system of the dishwasher.

FIG. 8 is an illustration of an embodiment of portions of the hydraulic system of the dishwasher for wastewater recycling.

FIG. 9 is an illustration of an embodiment of a wash tank drainage assembly in the wastewater recycling system.

FIG. 10 is an illustration of an embodiment of the wastewater heat recovery module placed in a wastewater tank of the dishwasher.

FIG. 11 is an illustration of an embodiment of portions of the dishwasher showing air and steam flow during operation.

FIG. 12 is an illustration of an embodiment of portions of the dishwasher showing a steam reduction module.

FIG. 13 is an illustration of an embodiment of portions of the steam reduction module showing steam flow and clean water flow for steam heat recovery.

FIG. 14 is an illustration of an embodiment of portions of the steam reduction module including a room air funnel and an air inlet.

FIG. 15 is an illustration of an embodiment of a steam heat exchange coil of the steam reduction module.

 DETAILED DESCRIPTION

The following detailed description of the present subject matter refers to subject matter in the accompanying drawings which show, by way of illustration, specific aspects and embodiments in which the present subject matter may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present subject matter. References to “an”, “one”, or “various” embodiments in this disclosure are not necessarily to the same embodiment, and such references contemplate more than one embodiment. The scope of the present invention is defined by the appended claims, along with the full scope of legal equivalents to which such claims are entitled.

The present subject matter relates to methods and devices for dispensing one or more dishwashing agents in a dishwasher and controlling the dispensing using a temperature sensed from the dishwasher. As used in the present disclosure, a “dishwasher” (also known as dish washing machine, warewasher, or warewashing machine) can include any type of washing machine that can use detergent for cleaning and/or sanitizing purposes in domestic or commercial settings. Objects to be washed in a dishwasher can include dinnerware, flatware, pots and pans, cutlery, flatware, glasses, kitchenware, serving pans, trays, and the like. Such objects can be placed in a dishwasher rack in the dishwasher. The “dishwasher rack” (also known as warewashing rack) can include any rack that is used in a dishwasher for holding any objects to be washed. Unless noted otherwise, a “rack” in the present disclosure refers to a dishwasher rack. The rack can be a built-in part of the dishwasher or a removable accessory suitable for use in the dishwasher. The rack can be a peg rack or an open rack and can have any size and shape suitable for the dishwasher. Each dishwasher can include one or more built-in racks and/or can host one or more removable racks.

As used in the present disclosure, a “cleaning cycle” of the dishwasher can include various operational periods, such as one or more of a descaling period, a washing period, a rinsing period, and a drying period, depending on the availability of respective operational modes in the dishwasher and settings entered by a user of the dishwasher. “Cleaning” can include cleaning only, sanitizing only, cleaning and sanitizing, descaling and cleaning, or descaling, cleaning, and sanitizing. A “descaling period” includes a period or operational mode that is intended for a descaling liquid formed by water and a descaler to be applied to the objects being cleaned. A “washing period” includes a period or operational mode that is intended for a washing liquid formed by water and a detergent to be applied to the objects being washed. A “rinsing period” includes a period or operational mode that is intended for water, or a rinsing liquid formed by water and a rinse aid and/or a sanitizer, to be applied to the objects being cleaned. Some dishwashers (e.g., commercial dishwashers) may include a rinsing period that is primarily for sanitizing through heat and/or chemical means. The descaler, detergent, rinsing aid, and sanitizer can each be a chemical agent or a mixture of chemical agents in liquid or solid form. A “drying period” includes a period or operational mode that is intended for the cleaned objects to be dried by air flow and/or heat, without additional water and/or chemical agent applied.

A trend of franchising food service businesses has raised a need for miniaturizing stores while maximizing store area utilization and the diversifying kitchen equipment. A store (e.g., restaurant) may face the challenge of increasing usage of electrically powered equipment without increasing the capacity of the existing electrical power system. The electrical power available for operating a dishwasher, an electrical appliance commonly used in a restaurant or other food service establishment, may be limited, while the cleaning effectiveness of the dishwasher is not to be compromised. Therefore, there is a need for minimizing the space needed for placing the dishwasher as well as the space needed for on-site maintenance and repair of the dishwasher, and there is a need for improving the power efficiency of the dishwasher while ensuring effectiveness of cleaning and sanitization, for example to meet or exceed hygiene requirements for operating a food service business.

FIGS. 1A, 1B, 1C, and 1D are illustrations of an embodiment of a dishwasher 100. As shown in FIGS. 1A-1D and discussed as an example for illustrative but not restrictive purposes, dishwasher 100 is a hood-type dishwasher that includes a hood 102 to cover a wash chamber (also known as a main wash chamber) 101 during each cleaning cycle. A hood lifting handle 103 can be elevated by a user to open hood 102 for loading objects to be washed into wash chamber 101 before a cleaning cycle, lowered by the user to close hood 102 to cover wash chamber 101 before starting the cleaning cycle, and elevated by the user to open hood 102 for unloading the cleaned objects after the cleaning cycle is completed. A hood lock 104 installed on hood 102 is automatically locked when a cleaning cycle starts to prevent hood 102 from being accidentally opened during the clean cycle. FIG. 1A shows a front view of dishwasher 100 when hood 102 is closed. FIG. 1B shows a side view of dishwasher 100 when hood 102 is closed. FIG. 1C shows a side view of dishwasher 100 when hood 102 is open. FIG. 1D shows a top view of dishwasher 100.

Dishwasher 100 includes a dispenser 105 that contains various chemical agents for dispensing during different periods of the cleaning cycle. Each chemical agent may be in liquid or solid form, and dispenser 105 is configured to accommodate liquid and/or solid forms for each chemical agent, depending on the form(s) of the chemical agent that is available and intended to use. Each chemical agent in dispenser 105 is refillable. In one example, dishwasher 100 can perform cleaning cycles including a descaling period, a washing period, and a rinsing period, and dispenser 105 is an integrated dispenser that can contain a descaler, a detergent, and a rinse aid and can dispense the descaler for use during the descaling period, the detergent for use during the washing period, and the rinse aid for use during the rinsing period.

Dishwasher 100 includes a user interface 106 that visually and/or audially indicates its operational status and allows the user to control its operations. User interface 106 can include a display screen, such as a touchscreen that can display the operation status of dishwasher 100 and receive commands and other information from the user. User interface 106 can include a power switch for the user to turn the electrical power for dishwasher 100 on and off. User interface 106 allows the user to start a cleaning cycle, optionally after indicating to the user that the cleaning cycle is ready to start (e.g., after hood 102 is closed). In one example, user interface 106 allows the user to select which period(s) to include in the cleaning cycle. The user may select only the rinsing period when, for example, dishes are known to be clean but needs disinfection. The user may select the washing and rinsing periods only when a need for descaling dishes is not indicated. In another example, user interface 106 is configured (e.g., programmed) for following a hygiene procedure and/or complying with a regulation for ensuring food safety.

Dishwasher 100 has a main frame (e.g., a welded metal structure) and a top structure affixed to the main frame. The top structure provides a roof for wash chamber 101 and does not move with hood 102. Hood 102 has a 3-panel structure with a front panel and two lateral panels, without a top panel or roof. Components such as dispenser 105 and user interface 106 are placed on the top structure without moving with hood 102. Allowing components to be positioned over wash chamber 101 without moving with hood 102 results in space saving while hood 102 can be made light and hence easy to lift.

Dishwasher 100 provides high space and power efficiency to lower operational cost and/or allowing a food service establishment to operate under limited space and/or electrical power capacity. For example, dishwasher 100 includes an internal wastewater recycling system 107 and an internal steam reduction module 111 to recover thermal energy resulting from the operations during each cleaning cycle for heating clean water to be used in the operations. Wastewater recycling system 107 includes a wash tank (also known as main wash tank) 108 recycling a hot washing liquid to be sprayed into, and returning from, wash chamber 101 during the washing period and a wastewater tank 109 (also known as overflow tank) to receive excessive hot washing liquid from wash tank 108 as wastewater. A heat exchange module is placed in wastewater tank 109 to heat clean water while cooling the wastewater before it is discharged to a drain (e.g., a drain connected to the sewage of the building). The heated clean water is to be added to wash tank 108 and a booster tank (also known as rinse tank) 110 as needed. In the illustrated example, booster tank 110 receives the clean water and the descaler to form a descaling liquid to be sprayed into wash chamber 101 during the descaling period and receives the clean water and the rinse aid to form a rinsing liquid to be sprayed into wash chamber 101 during the rinsing period. Steam reduction module 111 includes a fan 112 to draw steam from wash chamber 101 and a condenser 113 positioned in the steam path to condense the steam while heating the clean water (in addition to the heat recovery from the wastewater). Fan 112 blows the remaining steam out of dishwasher 100.

Dishwash 100 can be sized to allow for easy operation and maintenance by a user having a height of 150 cm or taller. Force required to open hood 102 by elevating hood lifting handle 103 can be around 3.5 kg or lighter. In one example, wash tank 108 has a capacity of about 24 L, wastewater tank 108 has a capacity of about 12 L, and booster tank 110 has a capacity of about 10 L.

FIG. 2 is an illustration of an embodiment of dishwasher 100 with several accessories. As shown in FIG. 2 as an example for illustrative but not restrictive purposes, the accessories can include a dirty dish stand 220, a clean dish stand 223, a dishwasher rack 224, and a vent hood 225. Dirty dish stand 220 includes one or more sinks 221 and one or more faucets 222. When necessary or convenient, dishes and/or other objects to be cleaned can be placed in sink(s) 221 and pre-washed using water from faucet(s) 222 before being loaded into wash chamber 101 (with hood 102 open). Rack 224 can be placed in wash chamber 101 when empty, and the dishes and/or other objects can be placed into rack 224 for each cleaning cycle. After the cleaning cycle is completed, rack 224 loaded with the cleaned dishes and/or other objects can be removed from wash chamber 101 (with hood 102 open) and placed on clean dish stand 223 before use and/or further distribution. Vent hood 225 can vent the steam blown out of dishwasher 100 by fan 112 to outside of the building in which dishwasher 100 is placed.

FIG. 3 is an illustration of an embodiment of a hydraulic system 329 of dishwasher 100. As shown in FIG. 2 as an example for illustrative but not restrictive purposes, hydraulic system 329 can support liquid movement functions during the descaling period, the washing period, and the rinsing period.

Hydraulic system 329 includes a main water valve 335 (e.g., an electromagnetically controlled valve) that can be opened to receive clean water from a water source (e.g., a water main of the building). The clean water can be heated in wastewater tank 109 and then routed to wash tank 108 and booster tank 110. The clean water can also be routed to dispenser 105, when needed (e.g., for dissolving one or more chemical agents in solid form(s)), through a dispenser valve 336.

During the descaling period, the descaler is dispensed from dispenser 105 into booster tank 110 to form the descaling liquid with the heated clean water in booster tank 110. The descaling liquid is pumped by a rinse pump 333 to rinse arms 330. Rinse arms 330 are positioned above and under wash chamber 101 and rotated to spray the scaling liquid into wash chamber 101 from above and under. The descaling liquid flows into wash tank 108 after passing through wash chamber 101.

During the washing period, the detergent is dispensed from dispenser 105 into wash tank 108 to form the washing liquid with the heated clean water in wash tank 108. The washing liquid is pumped by a wash pump 331 to wash arms 332. Wash arms 332 are positioned above and under wash chamber 101 and rotated to spray the washing liquid into wash chamber 101 from above and under. The washing liquid returns to wash tank 108 after passing through wash chamber 101.

During the rinsing period, the rinse aid is dispensed from dispenser 105 into booster tank 110 to form the rinsing liquid with the heated clean water in booster tank 110. The rinsing liquid is pumped by rinse pump 333 to rinse arms 330. Rinse arms 330 are rotated to spray the rinsing liquid into wash chamber 101 from above and under. The rinsing liquid flows into wash tank 108 after passing through wash chamber 101.

Thus, wash tank 108 collects all the liquid sprayed into wash chamber 101. When the level of the liquid in wash tank 108 exceeds a set threshold, the excessive liquid flows into wastewater tank 109 as the wastewater. In an example, as illustrated in FIG. 3, hydraulic system 329 includes a wastewater recycling system that includes a drain valve 337 and two watertight or waterproof seals 338 and 339 to separate the wastewater from drain water (which is the wastewater ready to be discharged from dishwasher 100 to the drain. A drain pump 334 pumps the drain water out of the wastewater recycling system to the drain. When drain pump 334 is turned off and drain valve 337 is closed, the wastewater flows out of wash tank 108 into wastewater tank 109 and then flows out of wastewater tank 109 and turns into the drain at seal 339. When drain pump 334 is turned on and drain valve 337 is closed, the wastewater flows out of wastewater tank 109 (as being pumped) through the path including drain pump 334 and turns into the drain at seal 339. When drain valve 337 is open, the wastewater flows from wash tank to the drain directly (without flowing through wastewater tank 109 or drain pump 334. A heat exchange coil 363 is placed in wastewater tank 109. The clean water flows through heat exchange coil 363 to be heated by the wastewater before being routed into wash tank 109 or booster tank 110, while the wastewater is cooled by the clean water before being discharged to the drain.

FIGS. 4-6 illustrate examples of arrangement of various components in dishwasher 100. Various issues have been observed with existing commercial dishwasher designs. In one example, components of a dishwasher are arranged in a manner that obstruct access to various interior spaces where components need to be reached, detached, disassembled and/or reassembled, thereby making maintenance and repair difficult and time consuming. When the dishwasher is used in a small or crowded space, a limited accessibility to internal components can make on-site maintenance and repair impossible. In another example, the electrical control system of a dishwasher includes a control box that lacks the sturdiness needed to sustain its environment (e.g., hot, vibrating, and rotating) and wiring that is messy and difficult for identifying various electrical connections. Such an electrical control system is difficult to maintain and repair and may fail prematurely. In yet another example, a wastewater heat recovery system of a dishwasher includes a heat exchange coil placed in a wastewater tank for absorbing heat from the wastewater to heat clean water. The heat exchange coil has a dense tubing arrangement that makes daily cleaning of the wastewater tank difficult and likely ineffective, creating food safety risks during long-term use of the dishwasher. Connections between the heat exchange coil and wastewater pipes are weak and prone to leakage caused by vibration during the operation of the dishwasher.

The present subject matter as applied to dishwasher 100 addresses such issues. Components of dishwasher 100 are arranged for easy access during maintenance and repair. For example, key components are positioned for unobstructed access by opening a front cover of dishwasher 100. The electrical control system is constructed for reliability and durability for long-term use inside dishwasher 100, with wires routed in a simple and orderly fashion allowing for easy identification of electrical routings and connections. The heat recovery system is made detachable for convenience and effectiveness of daily cleaning, while structural stability and operational safety are ensured.

FIG. 4 is a perspective view illustration, and FIG. 5 is a cross-sectional view illustration, of an embodiment of component arrangement in a portion of dishwasher 100. FIGS. 4-5 show that key components are positioned near the front side of dishwasher 100 for easy access during maintenance or repair. The key components can include components that need regular maintenance services and/or components that likely need repair or replacement during the product lifetime of dishwasher 100. Examples of such key components as shown in FIGS. 4-5 include wash pump 331, rinse pump 333, drain pump 334, main water valve 335, wastewater tank 109, and an electrical controller box 460. FIG. 4 shows that when a front cover of dishwasher 100 is opened or detached, substantially unobstructed access is provided to these components, among other components, for maintenance, repair, and/or replacement. Such component arrangement can reduce the need for moving dishwasher to a different location for maintenance or repair.

Electrical controller box 460 has balanced length and width to lower requirement for the strength of its rotating part. All the wiring bundles are arranged from the bottom or side wall of wastewater tank 109, such that the wires are clear and easy to identify.

FIG. 6 is an illustration of an embodiment of a wastewater heat recovery module 662 as implemented in dishwasher 100. Wastewater tank 109 is affixed to the main frame of dishwasher 110 to ensure stable and reliable connections to other components and tubing of hydraulic system 329 to withstand vibrations during operation of dishwasher 100. Wastewater heat recovery module 662 is to be detachably placed in wastewater tank 109 and includes a wastewater heat exchange coil 663. Wastewater flows from wash tank 108 and leaves wastewater tank 109 through a wastewater bar 664 when the level of the wastewater in wastewater tank 109 exceeds a maximum level set by wastewater bar 664. Wastewater heat exchange coil 663 is configured to provide sufficient space between the coil turns to facilitate cleaning. Detachability of wastewater heat recovery module 662 allows cleaning of wastewater tank 109 without wastewater heat exchange coil 663 being an obstruction. Wastewater heat recovery module 662 is further discussed below with reference to FIGS. 7-10.

FIGS. 7-10 illustrate an example of wastewater heat recovery that can be implemented in dishwasher 100. Hood-type dishwashers are widely used in restaurants, as they are designed for cleaning a large load of tableware quickly to meet hygiene requirements for food services with cost efficiency. This requires high-speed continuous operation with high temperature liquid being applied to the tableware for thorough cleaning and sanitization. Such operation can consume much electrical energy, with a significant portion that that energy converted into thermal energy in the wastewater and steam produced during the cleaning cycles.

Hood-type dishwashers may wash and rinse tableware at high temperatures, thereby producing hot wastewater (e.g., at 70-80° C.). In one example of a dishwasher, the hot wastewater is discharged directly into a drain, resulting in waste of thermal energy. In another example, a dishwasher includes a built-in wastewater heat recovery system that includes a heat exchange coil affixed within the wastewater path (e.g., a wastewater tank). Because such a coil cannot be detached, it is difficult to clean the wastewater path for meeting hygiene requirements. A thorough cleaning of certain parts of the wastewater path including the coil may become impossible with various types of food residue washed off the tableware. The wastewater tank can be made detachable from the dishwasher for cleaning, but that requires frequent disconnection from and reconnection to drain pipes that increase the labor required for cleaning and the risk of leakage. In yet another example, a dishwasher is connected to an external wastewater heat recovery system. This requires extra space for operating the dishwasher, and the external wastewater heat recovery system, which is also subjected to the hygiene requirements, can be difficult to clean.

Therefore, there is a need for a wastewater heat recovery system to increase the power efficiency of the dishwasher by utilizing thermal energy of wastewater while being easy to clean. The present subject matter provides a dishwasher, such as dishwasher 100, with a wastewater recycling system that recovers a significant portion (e.g., about 35%) of the thermal energy from wastewater while being easy to clean by using a detachable heat exchange coil.

During a cleaning cycle, a certain amount of clean water is added to the hydraulic system of the dishwasher (e.g., for rinsing the objects being cleaned with clean water). An approximately equal amount of wastewater is discharged to the drain to keep the volume of liquid in the hydraulic system constant. The hydraulic system according to the present subject matter includes a wastewater recycling structure to collect the wastewater to be discharged and a detachable heat exchange coil in the wastewater recycling structure for heating the incoming clean water using the outgoing wastewater. The incoming water needs to be heated to a certain temperature for chemical agents used in the cleaning cycle to exert their intended power efficiently and/or for sterilization of the objects being cleaned. The present hydraulic system lowers the power consumption of the dishwasher by lowering the energy required for heating the incoming water and shortens the duration of the cleaning cycle by shortening the time required for heating the incoming water.

Advantages of a dishwasher, such as dishwasher 100 provided by wastewater heat recovery structure in the present hydraulic system include, but are not limited to:

    • a wastewater tank that can be thoroughly cleaned to minimize food safety risks;
    • utilization of a principle of heat exchange stratification of water, according to which wastewater of lower temperature (i.e., less thermal energy) is discharged to the drain first;
    • no need for extra space for operating the dishwasher;
    • reduced risk of water leakage associated with daily maintenance (including cleaning) of the dishwasher; and
    • simple operation and reduced cost of operation.

FIG. 7 is an illustration of an embodiment of portions of a wastewater recycling system 107 as implemented in dishwasher 100. Components of wastewater recycling system 107 as shown in FIG. 7 include wash tank 108, a wash tank drainage assembly 765 at the drain of wash tank 108, wastewater tank 109, and wastewater heat exchange coil 663 placed in wastewater tank 109. Wastewater tank 109 has a drainage connection 769. Wash tank drainage assembly 765 includes a drain bar 766, a filter 767, and a drainage connection 768. Drain bar 766 sets the maximum level of the washing liquid inside wash tank 108 beyond what the excessive washing liquid flows as the wastewater to wastewater tank 109 through drainage connection 768, drainage connection 769, and portions of hydraulic system 329 (as discussed above and further discussed below). Drain bar 766 can be lifted to drain all the washing liquid in wash tank 108. Filter 767 prevents large debris in the washing liquid from leaving wash tank 108 to cause blockage in the wastewater recycling portion of hydraulic system 329. Portions of wash tank drainage assembly 765 that are inside wash tank 108, including drain bar 766 and filter 767, can be detached for their cleaning and unobstructed cleaning of wash tank 108.

FIG. 8 is an illustration of an embodiment of portions of hydraulic system 329 of dishwasher 100 for wastewater recycling. This portion of hydraulic system 329 as shown in FIG. 8 includes:

    • wash tank 108, including a wash tank drain 870 (where wash tank drainage assembly 765 is placed);
    • wastewater tank 109, including a first wastewater tank drain 871 and a second wastewater tank drain 872 (where wastewater bar 664 is placed);
    • a drain pump 334;
    • a first drain seal 338 and a second drain seal 339;
    • a drainpipe 840 through which the wastewater is discharged from dishwasher 100 to the drain (e.g., the drain connected to the sewage of the building);
    • wastewater heat exchange coil 663, detachably placed in wastewater tank 109 and having an inlet 873 to receive the clean water and an outlet 874 to output the heated clean water; and
    • pipes/hoses/tubing of hydraulic system 329 connecting between these components for wastewater recycle with heat recovery.
      When drain pump 334 is turned off and drain valve 337 is closed:
    • the wastewater flows out of wash tank 108 through wash tank drain 870;
    • the wastewater turns at first drain seal 338 to flow into wastewater tank 109 through first wastewater tank drain 871;
    • the wastewater flows out of wastewater tank 109 through second wastewater drain 872; and
    • the wastewater turns at second drain seal 339 to flow into drain pipe 840.
      When drain pump 334 is turned on and drain valve 337 is closed:
    • the wastewater flows out of wastewater tank 108 through first wastewater tank drain 871;
    • the wastewater flows (as being pumped by drain pump 334) through the path including drain pump 334, passing by first drain seal 338; and
    • the wastewater turns at second drain seal 339 to flow into drain pipe 840.
      When drain valve 337 is open, the wastewater flows out of wash tank 108 through wash tank drain 870 and drain valve 337 to drain pipe 840 directly (without flowing through wastewater tank 109 or drain pump 334). In one example, operations of hydraulic system 329 including the wastewater recycling are automatically controlled and/or electronically controlled using user interface 106 while drain bar 766 is in place in wash tank 108. A manual process of draining all liquid from wash tank 108 and wastewater tank 109 can be performed by removing drain bar 766 from wash tank drainage assembly 765.

FIG. 9 is an illustration of an embodiment of wash tank drainage assembly 765. Filter 767 can prevent debris (e.g., solid food waste) from leaving wash tank 108 through wash tank drain 870. The debris is to be removed when wash tank 108 is being cleaned. In one example, a removable filter is to be placed over wash tank 108 to prevent larger debris from entering wash tank 108, and filter 767 is to filter the remaining, smaller debris. Drain bar 766 can keep the washing liquid inside wash tank 108 until the level of the washing liquid reaches the maximum level set by drain bar 766. Drain bar 766 can be lifted to be separated from the rest of wash tank drainage assembly 765 to drain the washing liquid from wash tank 108 directly to drain pipe 840, for example when draining both wash tank 108 and wastewater tank 109 for cleaning according to a daily cleaning procedure established for dishwasher 100. First and second drain seals 338 separate the wastewater (before being released to drain pipe 840) from the drain water (wastewater ready to be released to drain pipe 840).

FIG. 10 is an illustration of an embodiment of wastewater heat recovery module 662 placed in wastewater tank 109 of dishwasher 100. Wastewater heat recovery module 662 includes wastewater heat exchange coil 663, which has inlet 873 to receive the clean water and outlet 874 to output the heated clean water. The wastewater and the clean water exchange heat inside wastewater tank 109 using wastewater heat exchange coil 663. As a result, the clean water is heated before being added to wash tank 108 and booster tank 110, while the wastewater is cooled before being discharged to the drain.

Wastewater heat exchange coil 663 is detachably connected to two water hoses of the clean water path of hydraulic system 329 in a manner that is easy for the user to disconnect and reconnect. Dishwasher 100 can be configured to allow easy, unobstructed temporary removal of wastewater heat exchange coil 663 from wastewater tank 109. A process of cleaning wastewater tank 109 and wastewater heat recovery module 662 (e.g., as part of the daily cleaning procedure established for dishwasher 100) can include:

    • removing a top lid (watertight or waterproof) of wastewater tank 109;
    • disconnecting wastewater heat exchange coil 663 from the water hoses;
    • removing wastewater heat exchange coil 663 from wastewater tank 109;
    • cleaning wastewater tank 109 and wastewater heat exchange coil 663;
    • placing wastewater heat exchange coil 663 back to wastewater tank 109;
    • connecting wastewater heat exchange coil 663 back to the water hoses; and
    • placing the top lid back on wastewater tank 109
      Wastewater heat exchange coil 663 has a structure that is designed for easy cleaning, for example by having sufficient space between loops of the coil and a “non-stick” surface of the coil.

The wastewater heat recovery system for dishwasher 100 has been tested with a prototype wastewater heat exchange coil 663 constructed using a pipe having a diameter of about 12 mm, accommodating about 1.3 L of clean water inside, and providing a heat exchange surface area of about 0.56 m2. Volume of the wastewater in wastewater tank is about 12 L. When the temperature of the wastewater entering wastewater tank is about 65° C., and the temperature of the wastewater exiting the wastewater tank is about 37-40° C., a heat exchange efficiency of about 35% was achieved. Testing with performing multiple cleaning cycles with the wastewater heat recovery system running and with the wastewater heat recovery system bypassed showed an overall power consumption of about 21% for dishwasher 100.

FIGS. 11-15 illustrate an example of steam heat recovery that can be implemented in dishwasher 100. Hot steam is produced in the wash chamber of a dishwasher during the operation of the dishwasher. A steam reduction system can heat clean water while condensing the steam, thereby reducing the amount of steam emitted from the dishwasher while reducing the energy needed for heating the clean water.

In an example of a hood-type dishwasher, a steam heat exchange coil is used in a condenser to pass the clean water through steam, thereby condensing the steam while heating the clean water. However, the coil can be too long such that it requires large space in the dishwasher while lowering the water pressure in the hydraulic system of the dishwasher, resulting in slow or insufficient water supply for washing and rinsing the objects being cleaned. Therefore, there is a need for a steam reduction module that provides for heat recovery from steam at a high heat exchange efficiency while maintaining a stable water pressure in the hydraulic system required for proper operation of the dishwasher during the washing and rinsing periods.

The present subject matter provides a dishwasher, such as dishwasher 100, with a steam reduction module that draws hot steam into a condenser in which the hot steam is condensed while clean water is heated at a high heat exchange efficiency while maintaining the pressure in the hydraulic system of the dishwasher, without significantly increasing the overall size of the dishwasher. Instead of using a single long pipe, a steam heat exchange coil according to the present subject matter includes multiple short pipes connected in parallel to reduce loss of water pressure in the coil.

FIG. 11 is an illustration of an embodiment of portions of dishwasher 100 showing air and steam flow during operation. During each cleaning cycle, hot steam results from the hot liquid sprayed into wash chamber 101 to blast the objects being washed. The hot steam is to be vented out of dishwasher 100 for its safe and continued operation.

FIG. 12 is an illustration of an embodiment of portions of dishwasher 100 showing a steam reduction module 1211 as implemented in dishwasher 100. FIG. 13 is an illustration of an embodiment of portions of the steam reduction module 1211 showing steam flow and clean water flow for steam heat recovery. Steam reduction module 1211 is an example of steam reduction module 111 and includes a fan 1212 (e.g., a crossflow fan) and a condenser 1213. Fan 1212 is positioned to draw steam from wash chamber 101 (within hood 102, when hood 102 is closed) and blow remaining steam out of the dishwasher for emission into the environment (e.g., vent hood 225, if installed). Condenser 1213 includes a steam heat exchange coil for exchanging heat between the hot steam and the clean water, as further discussed below with reference to FIG. 15. Condenser 1213 is positioned in the path of the steam flow as shown in FIGS. 12-13 to cool the steam while heating the clean water inside the steam heat exchange coil;

As shown in FIGS. 12-13, dishwasher 100 includes a back frame 1180 (e.g., as part of the dishwasher's main frame. After existing wash chamber 101, the steam flows primarily through a path in an upper portion of back frame 1180 to be emitted from the top of back frame 1180. Steam reduction module 1211 is positioned in this path within the upper portion of back frame 1180.

FIG. 14 is an illustration of an embodiment of portions of the steam reduction module optionally including a room air funnel 1481 and an air inlet 1482. Funnel 1481 is positioned at or near the top of back frame 1180. Fan 1212 draws the steam from wash chamber 101 and blows the steam remaining after passing through condenser 1213 into funnel 1481 to be emitted from dishwasher 100. Air inlet 1482 allows cool air to be drawn by fan 1212 into steam reduction module 1211 to further cool down the steam and to cool down funnel 1481. The optional use of funnel 1481 and air inlet 1482 can reduce the variation in the temperature of the remaining steam emitted from dishwasher 100. As shown in FIG. 14, air inlet 1482 has an opening positioned lower than fan 1212, and funnel 1481 has an opening positioned higher than fan 1212, when dishwasher 100 is set up for operation.

FIG. 15 is an illustration of an embodiment of a steam heat exchange coil 1587 of a condenser 1513, which is an example of condenser 1213. Condenser 1213 includes a clean water inlet 1585 to receive the clean water and a clean water outlet 1586 to output the heated clean water, a steam heat exchange coil 1587 coupled between clean water inlet 1585 and clean water outlet 1586, and thermal conductive fins 1588 coupled to steam heat exchange coil 1587. As shown in FIG. 15, steam heat exchange coil 1587 includes multiple individual loops 1587A, 1587B, and 1587C connected in parallel and each directly connected between cleaning water inlet 1585 and cleaning water outlet 1586. Compared to using a single long coil, using the multiple individual loops does not significantly reduce the pressure in hydraulic system 329. As shown in FIG. 15 as an example for illustrative but not restrictive purposes, steam heat exchange coil 1587 includes 3 loops: 1587A, 1587B, and 1587C. The number of loops and specific geometrical design of each loop can vary depending on design objectives and constraints, as understood by those skilled in the art. Loops 1587A, 1587B, and 1587C each receives the clean water from clean water inlet 1585 directly (without going through another loop) and outputs the heated clean water to clean water outlet 1586 (without going through another loop). Steam heat exchange coil 1587, including each of loops 1587A, 1587B, and 1587C, transfers thermal energy from the steam to the clean water, thereby heating the clean water while condensing the steam. Thermal conductive fins 1588 (e.g., made of aluminum) can absorb thermal energy from the steam and conduct the absorbed thermal to steam heat recovery coil 1587, thereby increasing the heat transfer efficiency of steam reduction module 1211.

The steam reduction module for dishwasher 100 has been tested with a prototype condenser 1513 and a crossflow fan having a flow rate of about 5.3 m3/min flow. As a result of using the steam reduction module, the temperature of the clean water rose by about 10° C., the amount of steam was reduced by about 90%, and the temperature of the steam was reduced from about 35-55° C. (varying during the cleaning cycle) to about 30° C.

Any one or any combination of the various embodiments of the present subject matter as discussed in this disclosure can be implemented in a dishwasher, for example to facilitate access to various components for maintenance and/or repair, to increasing power efficiency of the dishwasher by heat exchange between clean water and wastewater, to increasing power efficiency of the dishwasher while reducing stead emission by heat exchange between clean water and steam, and/or to facilitate cleaning of the dishwasher to ensure proper operation and to comply with a cleaning procedure and/or food safety regulation. Some non-limiting examples (Examples 1-40) of the present subject matter are provided as follows:

In Example 1, a dishwasher configured to perform cleaning cycles each including a washing period and a rinsing period for cleaning objects is provided. The dishwasher may include a wash chamber, a wash tank, a wastewater tank, and a wastewater heat exchange coil. The wash chamber may be configured to hold the objects. The wash tank may be configured to contain a washing liquid to be sprayed into the wash chamber during the washing period, to receive a returning liquid from the wash chamber to be added to the washing liquid, and to release a portion of the washing liquid when a level of the washing liquid in the wash tank exceeds a threshold level. The wastewater tank may be configured to receive wastewater from the wash tank and to release the received wastewater to a drain pipe. The wastewater includes the portion of the washing liquid released from the wash tank. The wastewater heat exchange coil may be configured to be detachably placed in the wastewater tank and to transfer thermal energy from the wastewater to heat clean water. The wastewater heat exchange coil has a clean water inlet to receive the clean water and a clean water outlet to output the heated clean water.

In Example 2, the subject matter of Example 1 may optionally be configured to include a hydraulic system including the wash tank and the wastewater tank and configured to receive the heated clean water from the wastewater heat exchange coil and to transmit a portion of the received heated clean water into the wash tank.

In Example 3, the subject matter of Example 2 may optionally be configured such that the hydraulic system further includes a rinse tank configured to contain a rinsing liquid to be sprayed into the wash chamber during the rinsing period, and the hydraulic system is further configured to transmit another portion of the received heated clean water into the rinse tank.

In Example 4, the subject matter of Example 2 may optionally be configured such that the hydraulic system includes a drain pump, the wastewater tank includes a first wastewater tank drain and a second wastewater tank drain, and the hydraulic system is configured to allow the wastewater to enter the wastewater tank through the first wastewater tank drain and to be released to the drain pipe through the second wastewater tank drain when the drain pump is turned off and to be pumped to the drain pipe through the first wastewater tank drain and the drain pump when the drain pump is turned on.

In Example 5, the subject matter of Example 2 may optionally be configured such that the wash tank includes a wash tank drain through which the portion of the washing liquid is released, and the hydraulic system further includes a drain valve configured to allow the washing liquid to be released from the wash tank to the drain pipe through the wash tank drain and the drain valve when the drain valve is open.

In Example 6, the subject matter of Example 5 may optionally be configured to further include a wash tank drainage assembly including a filter configured to prevent debris in the washing liquid from entering the wash tank drain and a detachable drain bar configured to keep the washing liquid inside the wash tank and to be lifted to release the washing liquid from the wash tank to the drain pipe through the drain valve when the drain valve is open.

In Example 7, the subject matter of Example 5 may optionally be configured such that the hydraulic system further includes seals configured to separate the wastewater from the drain pipe when the drain valve is closed.

In Example 8, the subject matter of Example 2 may optionally be configured such that the hydraulic system includes a cold clean water hose and a heated clean water hose, and the clean water inlet of the wastewater heat exchange coil is configured to be detachably connected to the cold clean water hose to form a watertight connection, and the clean water outlet of the wastewater heat exchange coil is configured to be detachably connected to the heated clean water hose to form another watertight connection.

In Example 9, the subject matter of Example 1 may optionally be configured to further include a lid configured to be detachably attached to the wastewater tank as a watertight or waterproof top cover for the wastewater tank.

In Example 10, the subject matter of any one or any combination of Examples 1 to 9 may optionally be configured to include a front cover that is openable or detachable and components requiring periodic maintenance arranged for unobstructed access when the front cover is opened or detached.

In Example 11, the subject matter of Example 10 may optionally be configured such that the components requiring periodic maintenance include an electrical control box, and to further include wires providing for multiple electrical connections to the electrical control box. The wires are arranged in a manner allowing for visual identification of each connection of the electrical connections.

In Example 12, the subject matter of any one or any combination of Examples 1 to 9 may optionally be configured to further include a steam reduction module including a fan and a condenser. The fan is configured to draw steam from the wash chamber and to blow remaining steam out of the dishwasher. The condenser is placed in a path of the steam between the wash chamber and the fan and configured to condense the steam drawn into the steam reduction module into the remaining steam while heating additional clean water. The condenser includes an additional clean water inlet to receive the additional clean water, an additional clean water outlet to output heated additional clean water, and a steam heat exchange coil including multiple loops each connected to the additional clean water inlet directly to receive a portion of the received additional clean water and connected to the additional clean water outlet directly to output a portion of the heated additional clean water.

In Example 13, the subject matter of Example 12 may optionally be configured to further include a room air funnel, and such that the fan is positioned to blow the remaining steam out of the dishwasher through the room air funnel.

In Example 14, the subject matter of Example 13 may optionally be configured to further include a cool air inlet configured and positioned to allow cool air to be drawn by the fan into the steam reduction module for cooling the steam and the room air funnel, and such that the cool air inlet has an opening positioned lower than the fan, and the funnel has an opening positioned higher than the fan.

In Example 15, the subject matter of Example 12 may optionally be configured such that the condenser includes multiple thermal conductive fins connected to the steam heat exchange coil and configured to absorb heat from the steam and to transfer the absorbed heat to the steam heat exchange coil.

In Example 16, a dishwasher configured to perform cleaning cycles each including a washing period and a rinsing period for cleaning objects is provided. The dishwasher may include a wash chamber and a steam reduction module. The wash chamber may be configured to hold the objects and to allow the objects to be washed during the washing period and rinsed during the rinsing period. The steam reduction module may include a crossflow fan and a condenser. The fan may be configured to draw steam from the wash chamber and to blow remaining steam out of the dishwasher. The condenser may be placed in the path of the steam between the wash chamber and the fan and configured to condense the steam drawn into the steam reduction module into the remaining steam while heating clean water. The condenser may include a clean water inlet to receive clean water, a clean water outlet to output heated clean water, and a steam heat exchange coil including multiple loops each connected to the clean water inlet directly to receive a portion of the received clean water and connected to the clean water outlet directly to output a portion of the heated clean water.

In Example 17, the subject matter of Example 16 may optionally be configured to further include a room air funnel, and such that the fan is positioned to blow the remaining steam out of the dishwasher through the room air funnel.

In Example 18, the subject matter of Example 17 may optionally be configured to further include a cool air inlet configured and positioned to allow cool air to be drawn by the fan into the steam reduction module for cooling the steam and the room air funnel. The cool air inlet has an opening positioned lower than the fan. The room air funnel has an opening positioned higher than the fan.

In Example 19, the subject matter of Example 16 may optionally be configured such that the condenser includes multiple thermal conductive fins connected to the steam heat exchange coil and configured to absorb heat from the steam and to transfer the absorbed heat to the steam heat exchange coil.

In Example 20, the subject matter of any one or any combination of Examples 16 to 19 may optionally be configured such that the fan includes a crossflow fan.

In Example 21, the subject matter of any one or any combination of Examples 16 to 19 may optionally be configured such that the dishwasher is a hood-type dishwasher including a main frame including a back frame having a top portion positioned higher than the wash chamber, and such that the steam reduction module is positioned in the top portion of the back frame.

In Example 22, the subject matter of Example 21 may optionally be configured to include a front cover and components requiring periodic maintenance. The front cover is attached to the main frame and openable or is detachably attached to the main frame. The components requiring periodic maintenance are arranged for unobstructed access when the front cover is opened or detached.

In Example 23, the subject matter of Example 22 may optionally be configured such that the components requiring periodic maintenance includes an electrical control box, and to further include wires providing for multiple electrical connections to the electrical control box. The wires are arranged in a manner allowing for visual identification of each connection of the electrical connections.

In Example 24, the subject matter of Example 21 may optionally be configured to include a top structure affixed to the main frame and over the wash chamber, components placed on the top structure, and a hood configured to cover front and lateral sides of the wash chamber during the cleaning cycles and to be lifted to expose the wash chamber between the cleaning cycles without moving the top structure.

In Example 25, a method for operating a dishwasher is provided. The dishwasher is configured to perform cleaning cycles each including a washing period and a rinsing period for cleaning objects. The method may include: receiving a portion of a washing liquid from a wash tank containing the washing liquid; spraying the received portion of the washing liquid into a wash chamber loaded with the objects during the washing period; collecting liquid from the wash chamber and returning the collected liquid into the wash tank to add to the washing liquid; transferring an excessive portion of the washing liquid from the wash tank to a wastewater tank as wastewater, the excessive portion of the washing liquid resulting from a level of the washing liquid in the wash tank exceeding a threshold level; transferring thermal energy from the wastewater to cleaning water flowing through a wastewater heat exchange coil detachably placed in the wastewater tank, to heat the clean water; and transferring the wastewater from the wastewater tank to a drain pipe.

In Example 26, the subject matter of Example 25 may optionally further include adding a portion of the heated clean water to the washing liquid in the wash tank.

In Example 27, the subject matter of Example 26 may optionally further include receiving a portion of a rinsing liquid from a rinse tank containing the rinsing liquid, spraying the received portion of the rinsing liquid into the wash chamber loaded with the objects during the rinsing period, and adding another portion of the heated clean water to the rinsing liquid in the rinsing tank.

In Example 28, the subject matter of Example 25 may optionally further include: transferring the excessive portion of the washing liquid from the wash tank to the wastewater tank as wastewater through a first wastewater tank drain and transferring the wastewater from the wastewater tank to the drain pipe through a second wastewater tank drain of the wastewater tank when a drain pump is turned off; and transferring the wastewater from the wastewater tank to the drain pipe through the first wastewater tank drain and the drain pump when the drain pump is turned on.

In Example 29, the subject matter of Example 25 may optionally further include transferring the washing liquid from the wash tank to the drain pipe through a drain valve when the drain valve is open.

In Example 30, the subject matter of Example 29 may optionally include setting the threshold level using a wash tank drainage assembly affixed to a bottom of the wash tank, using a filter of the wash tank drainage assembly to prevent debris in the washing liquid from entering the wastewater tank, using a detachable drain bar of the wash tank drainage assembly to keep the washing liquid inside the wash tank when the drain valve is closed, and lifting the detachable drain bar to release the washing liquid from the wash tank to the drain pipe through the drain valve when the drain valve is open.

In Example 31, the subject matter of any one or any combination of Examples 25 to 30 may optionally further include drawing steam from the wash chamber, condensing the steam while heating additional clean water using a steam heat exchange coil including multiple loops each connected to an additional clean water inlet directly to receive a portion of the additional clean water and connected to an additional clean water outlet directly to output a portion of heated additional clean water, and blowing steam remaining from the condensing out of the dishwasher.

In Example 32, the subject matter of blowing the steam remaining from the condensing out of the dishwasher as found in Example 31 may optionally further include blowing the remaining steam out of the dishwasher through a room air funnel at a top portion of the dishwasher.

In Example 33, the subject matter of Example 32 may optionally further include drawing air from outside of the dishwasher to cool the steam and the room air funnel.

In Example 34, the subject matter of Example 31 may optionally further include absorbing thermal energy from the steam and transferring the absorbed thermal energy to the steam heat exchange coil using multiple thermal conductive fins connected to the steam heat exchange coil.

In Example 35, a method for operating a dishwasher is provided. The dishwasher is configured to perform cleaning cycles each including a washing period and a rinsing period for cleaning objects. The method may include holding the objecting in a wash chamber, washing the objects during the washing period, rinsing the objects during the rinsing period, drawing steam from the wash chamber during each cycle of the cleaning cycles, condensing the steam while heating additional clean water using a steam heat exchange coil including multiple loops each connected to an additional clean water inlet directly to receive a portion of the additional clean water and connected to an additional clean water outlet directly to output a portion of heated additional clean water, and blowing steam remaining from the condensing out of the dishwasher.

In Example 36, the subject matter of blowing the steam remaining from the condensing out of the dishwasher as found in Example 35 may optionally include blowing the remaining steam out of the dishwasher through a room air funnel at a top portion of the dishwasher.

In Example 37, the subject matter of Example 36 may optionally further include drawing air from outside of the dishwasher to cool the steam and the room air funnel.

In Example 38, the subject matter of Example 37 may optionally further using a fan to drawing the steam from the wash chamber, to blow the steam remaining from the condensing out of the dishwasher, and to draw the air from outside of the dishwasher.

In Example 39, the subject matter of using the fan as found in Example 38 may optionally include using a crossflow fan.

In Example 40, the subject matter of any one or any combination of Examples 35 to 38 may optionally further include absorbing thermal energy from the steam and transferring the absorbed thermal energy to the steam heat exchange coil using multiple thermal conductive fins connected to the steam heat exchange coil.

This application is intended to cover adaptations or variations of the present subject matter. It is to be understood that the above description is intended to be illustrative, and not restrictive. The scope of the present invention should be determined with reference to the appended claims, along with the full scope of legal equivalents to which such claims are entitled.

Claims

1-24. (canceled)

25. A method for operating a dishwasher configured to perform cleaning cycles each including a washing period and a rinsing period for cleaning objects, comprising:

receiving a portion of a washing liquid from a wash tank containing the washing liquid;
spraying the received portion of the washing liquid into a wash chamber loaded with the objects during the washing period;
collecting liquid from the wash chamber and returning the collected liquid into the wash tank to add to the washing liquid;
transferring an excessive portion of the washing liquid from the wash tank to a wastewater tank as wastewater, the excessive portion of the washing liquid resulting from a level of the washing liquid in the wash tank exceeding a threshold level;
transferring thermal energy from the wastewater to cleaning water flowing through a wastewater heat exchange coil detachably placed in the wastewater tank, to heat the clean water; and
transferring the wastewater from the wastewater tank to a drain pipe.

26. The method according to claim 25, further comprising adding a portion of the heated clean water to the washing liquid in the wash tank.

27. The method according to claim 26, further comprising:

receiving a portion of a rinsing liquid from a rinse tank containing the rinsing liquid;
spraying the received portion of the rinsing liquid into the wash chamber loaded with the objects during the rinsing period; and
adding another portion of the heated clean water to the rinsing liquid in the rinsing tank.

28. The method according to claim 25, comprising:

transferring the excessive portion of the washing liquid from the wash tank to the wastewater tank as wastewater through a first wastewater tank drain and transferring the wastewater from the wastewater tank to the drain pipe through a second wastewater tank drain of the wastewater tank when a drain pump is turned off; and
transferring the wastewater from the wastewater tank to the drain pipe through the first wastewater tank drain and the drain pump when the drain pump is turned on.

29. The method according to claim 25, further comprising transferring the washing liquid from the wash tank to the drain pipe through a drain valve when the drain valve is open.

30. The method according to claim 29, comprising:

setting the threshold level using a wash tank drainage assembly affixed to a bottom of the wash tank;
using a filter of the wash tank drainage assembly to prevent debris in the washing liquid from entering the wastewater tank;
using a detachable drain bar of the wash tank drainage assembly to keep the washing liquid inside the wash tank when the drain valve is closed; and
lifting the detachable drain bar to release the washing liquid from the wash tank to the drain pipe through the drain valve when the drain valve is open.

31. The method according to claim 25, further comprising:

drawing steam from the wash chamber;
condensing the steam while heating additional clean water using a steam heat exchange coil including multiple loops each connected to an additional clean water inlet directly to receive a portion of the additional clean water and connected to an additional clean water outlet directly to output a portion of heated additional clean water; and
blowing steam remaining from the condensing out of the dishwasher.

32. The method according to claim 31, wherein blowing the steam remaining from the condensing out of the dishwasher comprises blowing the remaining steam out of the dishwasher through a room air funnel at a top portion of the dishwasher.

33. The method according to claim 32, further comprising drawing air from outside of the dishwasher to cool the steam and the room air funnel.

34. The method according to claim 31, further comprising absorbing thermal energy from the steam and transferring the absorbed thermal energy to the steam heat exchange coil using multiple thermal conductive fins connected to the steam heat exchange coil.

35. A method for operating a dishwasher configured to perform cleaning cycles each including a washing period and a rinsing period for cleaning objects, comprising:

holding the objects in a wash chamber;
washing the objects during the washing period;
rinsing the objects during the rinsing period;
drawing steam from the wash chamber during each cycle of the cleaning cycles;
condensing the steam while heating additional clean water using a steam heat exchange coil including multiple loops each connected to an additional clean water inlet directly to receive a portion of the additional clean water and connected to an additional clean water outlet directly to output a portion of heated additional clean water; and
blowing steam remaining from the condensing out of the dishwasher.

36. The method according to claim 35, wherein blowing the steam remaining from the condensing out of the dishwasher comprises blowing the remaining steam out of the dishwasher through a room air funnel at a top portion of the dishwasher.

37. The method according to claim 36, further comprising drawing air from outside of the dishwasher to cool the steam and the room air funnel.

38. The method according to claim 37, further comprising using a fan to drawing the steam from the wash chamber, to blow the steam remaining from the condensing out of the dishwasher, and to draw the air from outside of the dishwasher.

39. The method according to claim 38, wherein using the fan comprising using a crossflow fan.

40. The method according to claim 35, further comprising absorbing thermal energy from the steam and transferring the absorbed thermal energy to the steam heat exchange coil using multiple thermal conductive fins connected to the steam heat exchange coil.

41. The method according to claim 36, further comprising absorbing thermal energy from the steam and transferring the absorbed thermal energy to the steam heat exchange coil using multiple thermal conductive fins connected to the steam heat exchange coil.

42. The method according to claim 26, further comprising:

drawing steam from the wash chamber;
condensing the steam while heating additional clean water using a steam heat exchange coil including multiple loops each connected to an additional clean water inlet directly to receive a portion of the additional clean water and connected to an additional clean water outlet directly to output a portion of heated additional clean water; and
blowing steam remaining from the condensing out of the dishwasher.

43. The method according to claim 28, further comprising:

drawing steam from the wash chamber;
condensing the steam while heating additional clean water using a steam heat exchange coil including multiple loops each connected to an additional clean water inlet directly to receive a portion of the additional clean water and connected to an additional clean water outlet directly to output a portion of heated additional clean water; and
blowing steam remaining from the condensing out of the dishwasher

44. The method according to claim 29, further comprising:

drawing steam from the wash chamber;
condensing the steam while heating additional clean water using a steam heat exchange coil including multiple loops each connected to an additional clean water inlet directly to receive a portion of the additional clean water and connected to an additional clean water outlet directly to output a portion of heated additional clean water; and
blowing steam remaining from the condensing out of the dishwasher.
Patent History
Publication number: 20260198752
Type: Application
Filed: Feb 28, 2023
Publication Date: Jul 16, 2026
Inventors: Tian Qian (Shanghai), Wensheng Yu (Shanghai), Shuchen Zhou (Shanghai), Mingyue Zhao (Pudong), Kai Qiu (Pudong), Pu Li (Shanghai)
Application Number: 19/137,566
Classifications
International Classification: A47L 15/42 (20060101); A47L 15/00 (20060101); A47L 15/48 (20060101);