A dishwasher is an electro-mechanical device that cleans and rinses dirty dishes. A dishwasher carries out following functions:
● Fills tub with water
● Heats water to a suitable temperature
● Opens the detergent dispenser automatically at correct timing
● Waters the racks through jets to clean the dishes
● Drains the dirty water
● Rinses dishes by spraying more water
● Drains itself again
● Circulates hot air to dry off the dishes
Specifications & Features
Model #: EWDW6505GB0
Dishwasher Type: 24 inch built-in
Rating................................. 120 Volts, 60Hz
Separate Circuit................... 15 amp min.- 20 amp max.
Motor (Amps)....................... 0.75
Heater Wattage.................... 1200
Total Amps (load rated) ........ 10.0
Hi-Limit Thermostat.............. 200°F (93°C)
Suggested minimum incoming water temperature........... 120°F (49°C)
Pressure (PSI) min./max............................................... 20/120
Connection (NPT) ........................................................ 3/8"
Consumption (Normal Cycle) ........................................ 4.9 - 9.7 U.S. gal., 18.5 - 36.7 liters
Water valve flow rate (U.S. GPM) .................................. 0.83
Water recirculation rate (U.S. GPM) ............................. Approx. 19
Water fill time. ............................................................. 87 sec.
Annual Electricity (kWh/Year)....................................... 324
Gallons of Water per Cycle........................................... 4.35
Energy Factor.............................................................. 0.7
How it works
Figure 1 shows a schematic of the Electrolux Dishwasher that was dissected for obtaining educational material. An Electrolux dishwasher cleans by spraying a mixture of hot water and detergent through the spray arms against soiled surfaces. Each cycle begins with a pre-drain. Next, the dishwasher fills with water until the filter area is covered with water. Water is then pumped through the filter and spray arms. Soil particles go down the drain as the water is pumped out and replaced with clean water. The number of water fills vary with the cycle being used.
Water SystemThe water enters the system in through the water inlet see Figure 2.
In Figure 3 the water enters the base. Next the water enters the base see Figure 4 which then it travels through the recirculation loop. This loop is used for washing and rinsing the dishes. Once the system has finished the recirculation and dish washing or rinsing it then uses the waste water loop to dispose of the used water into the drain.
The purpose of the spray assembly is to direct pressured water at the dish surfaces from various angles. Water pressure driven by the cycle pump flows into the cleaning chamber through one stationary sprayer, and three rotating arms on the bottom, middle and top of the chamber. Input water pressure passes into the inside of the hollow plastic arms rested on pivots. The pivots consist of hollow cylinders which limit the arms to radial motion and allow water into the arms. Holes on the surface of the arms direct the pressure difference and water streams in different directions. Ultimately, more force is applied to streams which point to one side of the arm on either side of the central pivot. The force favors opposite arm sides on either side of the pivot, so that the arms are torqued in one rotational direction, the net force opposite to the net direction of the streams. The rotation of these arms cyclically varies the direction of all the streams increasing the span that they cover over the dishes.
1. Remove the top rack from the dishwasher
2. Fully disassemble the top rack as shown below.
3. Investigate the roller assembly. What unique feature(s) does this provide?
4. How are the various metal rack inserts attached to the main rack? Why is this joining method used?
5. Why are so many elements of this top rack adjustable? What potential problems does this pose for the designers and manufacturers? How might this affect long term durability of the rack system?
6. Re-assemble the top rack and return it to the dishwasher.
1. Remove the bottom rack from the unit and disassemble it as shown.
2. What are the similarities and differences between the top and bottom racks?
3. Are the top and bottom rack’s metal and plastic components interchangeable?
4. Not including the handle, how many metal fasteners are used? Why do you think this number is so low?
5. Investigate the wheel assembly. How are the wheels joined? Are there any bearings?
6. Reassemble the bottom tray and place it back in the dishwasher to complete this activity.
Bill of Materials
|Part #||Part Name||Qty||Material||Manufacturing Process||Assembly Scheme||Primary Function||Image|
|1||Tub Assembly||1||Metal||Stamped metal assembled||Main Unit||House components|
|2||Rack Rollers||2||Metal||Stamped and Bent||Top Rack||Support Top Rack|
|3||Rack Adjustment Mechanism||2||Steel/Plastic||Stamped/Injection Mold||Top Rack||Adjust Height of Top Rack|
|4||[Upper Rack]||1||Metal/Plastic||Welded & Bent Bar / Injection Mold||Top Rack||Hold Dishes|
|5||Mid Spray Assembly||1||Plastic||Injection Mold||Water System||Spray Top Rack Contents|
|6||Delivery Tube||1||Plastic||Injection Mold||Water System||Deliver Water to Mid Sprayer|
|7||Upper Spray||1||Plastic||Injection Mold||Water System||Spray Top Rack Contents from Above|
|8||Tub Gasket||1||Rubber||Cut||Water System||Make water tight seal|
|9||Power Vent||1||NA||NA||Heating System||Vent the main tub|
|10||Float Switch||1||Plastic||Injection Mold||Water System||Control Water level in Tub|
|11||Base Assembly||1||N/A||N/A||Heat and Water Systems||Main Control area, houses pumps and heaters|
|12||Feet||4||Rubber||Formed||NA||Provide traction for unit to avoid slipping||---|
|13||Base Tray||1||Plastic||Injection Mold||NA||Covers Base Assembly|
|14||Inner Kick||1||Metal||Stamp||Base Assembly||Cover front of base assembly, heat shield|
|15||Outer Kick||1||Metal||Stamp||Base Assembly||Cover Inner kick|
|16||Hinge Springs||2||Metal||Wound/Coiled||Door||Counter weight of the door, keep from falling when opening|
|17||Door Hinges||2||Metal||Formed||Door||Allows door to smoothly open and close|
|18||Door Assembly||1||NA||NA||Door||Houses all components of the door|
|19||Latch Assembly||1||Metal/PLastic||Stamped/Injection Mold||Door||Latches door and locks when in use|
|20||Door Gasket||1||Rubber||Formed||Door||Makes water Tight seal for door when closed|
|21||Towel Bar||1||Plastic||Injection Mold||Door||Acts as handle for door and holds hand towels|
|22||Control Console Unit||1||N/A||N/A||Door||User Control of machine functions|
|23||Base Adaptor||1||Plastic||Injection Mold||Base Assembly|
|24||[Lower Rack]||1||Metal/Plastic||Welded & Bent rod/Injection Mold||Racks||Hold dishes|
|25||Silverware Basket||1||Plastic||Injection Mold||Racks||Hold silverware for washing|
|26||Lower Spray||1||Plastic||Injection Molded||Water System||Sprays water|
|27||Sump||1||Plastic||Injection Molded||Water System||Base for horizontal filter|
|28||Spray Support||1||Plastic||Injection Molded||Water System||Directs water flow|
|29||Fine Filter||1||Plastic||Injection Molded||Water System||Catches fine particulate matter|
|30||Horizontal Filter||1||Metal||Stamped||Water System||Holds All Filters|
|31||Glass Trap||1||Plastic||Injection Molded||Water System||Catches large particulate matter|
|32||Inline Heater||1||Metal||Cast Metal||Water System||Heats Water|
|33||Circulatory Pump||1||Plastic||Injection Molded||Water System||Circulates water|
|34||Leak Detector||1||Plastic Fiberglass/ Metal||Fiberglass circuit and Molded Plastic Encasement||Water System||Detects leaks|
|35||Turbidity Sensor||1||Plastic||Injection Molded||Water System||Senses turbulence|
|36||Drain Pump||1||Plastic housing and metal motor||Injection Molded Plastic Motor is Wound||Water System||Pumps water|
|37||Drain Valve||1||Plastic||Injection Molded||Water System||Waste Water Disposal|
|38||Vertical Filter||1||Plastic||Injection Molded||Water System||Filters particulate matter|
|39||Drain Hose||1||Plastic||Injection Molded||Water System||Waste water removal|
|40||Side Drying Duct||1||Plastic||Injection Molded||Water System||Overflow mechanism|
|41||Lower Drying Duct||1||Plastic||Injection Molded||Water System||Collects overflowing water|
|42||Lower Fan||1||Plastic||Injection Molded||Base||Cools System|
|43||Water Inlet||1||Plastic||Injection Molded||Base||Lets water into system|
|44||Junction Box||1||Sheet Metal||Stamped||Base||Houses Connection Wires and Electrical Supply Circuit|
|45||Control Board||1||Plastic, Fabricated Circuit Board||Circuit Board with Injection Molded Casing||Base||Manages Dishwasher Functions|
|46||Control Board (Front)||---||---||---||Base||Indicate Component Errors and Failure|
Electrolux EWDW6505G CAD Models
|1||Control Panel & Door|
|3||Motor & Pump|
Assembly drawings and part list for the dishwasher: Assembly Drawings_Dishwasher
Explain disassembly processes
History and Background
There is an interesting history behind the development of dishwashers. The very first dishwasher was invented by Joel Houghton which was patented in 1850. It was then called "Table furniture cleaning machine" as shown in Figure 1. It was essentially a wooden machine with a hand-operated wheel that splashed water on dishes but it barely worked. In 1865, L.A. Alexander patented a device that used a hand crank and gearing to spin a rack of dishes through the dishwater which again did not function effectively. Later in 1886, Josephine Cochrane patentedthe invention of first practically operational dishwasher. The inspiration behind her invention was chipping of her fine chinaware due to the harsh handling it suffered by her servants. She unveiled her invention and showcased the dishwasher in 1893 World Fair, Chicago where she received enormous recognition from friends, hotels and restaurant owners. She then started a production factory to manufacture the dishwashers and called the company KitchenAid, which is one of the well-known brands of Whirlpool today.
There are a variety of dishwashers available in the market place to suit different lifestyles, with varying degrees of portability and installation requirements. Based on the users needs and requirements one among the following can be chosen.
Built-in Under Counter Dishwashers (Traditional):
Built-in dishwashers are very popular and used by a majority of homeowners. A built-in dishwasher is the standard 24-inch size built right into the kitchen cabinetry. Being prevalent, it offers a wide variety of styles, features and upgrades. It provides space-saving convenience, more selection options, higher loading capacity and can be made to match with exterior finishes of other kitchen appliances or cabinetry. These built-in installed units provide the best operating convenience, being permanently located for easy access with no need to relocate it to the kitchen sink every time you need to use it. As there is no hook-up to the faucet, kitchen sink can still be used for other purposes while the dishwasher is running. These dishwashers do require a plumbing installation to waterworks. Because of the standard width of dishwashers being 24 inches, a fair size cupboard is needed for installation. If there are ample cupboards in the kitchen, the convenience of a built-in dishwasher quickly outweighs the loss of storage space.
Compact or Counter Top Dishwashers:
A compact dishwasher is smaller in size as compared to the standard 24-inch sized dishwasher. Being only about 18 inches wide, compact dishwashers are best fit for small kitchens. They are the most economical of all models and need a counter or stand to be located close to the sink. They usually offer less wash programs and tend to be less energy efficient than larger machines, typically in the drying portion of a cycle. Newer models now have some enhanced washing cycles and heated drying.
Portable dishwashers are exactly what they sound like: self-contained dishwashers that can move. These models are great for smaller homes without much counter top or cabinetry space in the kitchen. They come in full-sized and counter top models and most full-sized portable dishwashers have a counter space on top. The water source for the machine is usually a hose that is hooked up to the kitchen faucet. Many of these machines have wheels for easy transport and some are made narrower to fit through doorways and in smaller kitchens.
Slimline dishwashers are slimmer taller models of traditional built-in dishwashers. These models are usually only about 18 inches wide and they come in both free-standing and built-in models. In some kitchens, the built-in models can be fitted in cabinets with the cabinet door attached to the dishwasher door. This allows the consumer to keep all their kitchen's cabinets uniform. Although theses dishwashers are compact, they tend to be high quality machines and some even feature a 'half-load' run cycle option to save water and energy on smaller loads. The major drawbacks of slimline dishwashers are that the machines are sometimes to tall for existing counters in a kitchen and the dishwasher can be relatively expensive when compared to traditional models.
The main concept behind drawer dishwashers is that they make it easier to place dishes in the dishwasher. Most other types of dishwashers require users to put the door down and pull the rack out before they can load dishes. With a drawer dishwasher, users only need to pull out the drawer (which is also the door) before loading the dishes. These models fit in the same space as traditional dishwashers and they are usually found under counter tops in the kitchen. They come in both single and two-door models. For two door models, each drawer is independent and can have its own wash settings. A benefit of this system is that users can still load one drawer while the other is in the midst of a wash.
Commercial dishwashers are large scale dishwashers found in restaurants or other businesses. They come in a variety of models such as stationary rack, single tank door type, single tank conveyor, and multiple tank conveyor. With stationary models, dishes remain inside the machine for the various rinses. Conveyor types use tanks to spray dishes as they move along a track in and then out of the dishwasher. The machines clean by using either hot water sanitizing (high temp.) or chemical sanitizing (low temp.).
Dishwashers Design Structure Matrix (DSM)
Electrolux Dishwasher DSM: Electrolux_Dishwasher_DSM
Economic Impact of this Product
Electrolux EWDW6505GB Retail Price: $1,299.00
-This dishwasher uses 4.9 to 8.5 gallons of water. Because of the water recycling method in a dishwasher, it does not need as much water. According to treehugger.com, a faucet flows at an average of 2 gallons per minute. Hand washing uses less water for a small amount of dishes, however, after about 5 minutes it will use more water than a dishwasher, and ultimately be more costly.
-This machine is the “largest usable capacity in its class” which allows for more items to be washed per load. Ultimately, this results in more efficient use of water compared to hand washing an equivalent amount, therefore saving money on water.
-There is a leak detection system to alert the consumer of water leakage so they don’t have to waste water or energy.
Environmental Impact of this Product
-As said before, this dishwasher uses 4.9 to 8.5 gallons of water. Because of the water recycling method in a dishwasher, it does not need as much water. According to treehugger.com, a faucet flows at an average of 2 gallons per minute. Hand washing uses less water for a small amount of dishes, however, after about 5 minutes it will use more water than a dishwasher, thus having more of an environmental impact than a dishwasher.
-This dishwasher is Energy Star qualified, so it uses 20-30% less energy than the required standards, making this a greener machine.
-The drying system uses a high-efficiency fan so it uses less energy.
-According to University of Bonn in Germany, the city of London could save 4.2 billion gallons of fresh water per year if every household used a dishwasher instead of hand washing. Applying this model to the rest of the world, we can see that dishwashers have the capability of saving billions of gallons of fresh water each year. In addition the immense water savings, dishwashers could conveniently save users' energy as well.
-Electrolux supplies dishwashers to over 150 countries.
-Electrolux has a gender-balanced and culturally diverse workforce. They claim it is a "key factor for success in meeting our market."
-Today Electrolux is a global leader in both household and appliances for professional use.
-This dishwasher is rated quiestest in its class.
Dishwasher Door and Door Lock Subsystem
The dishwasher door is a very important part of any dishwasher. The door seals the water from escaping from the inside of the machine and houses the controls for the dishwasher. The door prevents water from escaping by using seals that are placed around the perimeter of the door. The different controls that are on the door are the different wash cycles (Heavy, Auto, Normal, Eco, Quick, and High-Temp) and the start and stop buttons. The status window is located on the top of the dishwasher door and displays the current operation of the dishwasher and other vital information. This conforms with the minimalist design followed by many modern dishwashers. No controls or displays are visible when the door is closed. The STATUS window display will only appear when the door is open.
Because of this, the dishwasher is automatically programmed to cease operation when the door is open. To start a cycle, press the START on the touchpad and closing the door will start the cycle. To cancel when a cycle is running, open the door and press CANCEL. Close the door again and the dishwasher will start draining and then shutdown.
Opening the door during normal operation will only pause the selected cycle.
A handle is also located on the outside of the door to allow access to the inside of the dishwasher. The silverware basket and detergent reservoir are located on the inside of the door.
Child Lock Controls
"To prevent children from accidentally changing the dishwasher cycle or starting the dishwasher, a lock on the system controls can be set by pressing the DELAY TIME icon for 3 seconds. An indicator will light when the controls are locked and no new selections can be made while the controls are locked. To unlock, press the DELAY TIME icon until the indicator light goes off."
As you can see the door and door lock subsystem is very important in a dishwashers operation and design.
A system for heating the incoming water is crucial to make sure the dishwasher can adequately fulfill its main function. Our Electrolux model utilizes an inline heating mechanism, which heats up the input water as it passes through, rather than a heating coil that heats up a pool of water in the bottom. Once in the recycling loop, the water is constantly reheated each time it goes by, making sure that the temperature stays above the minimum 120°F (49°C). The different wash cycles cause the water temperature to vary depending on the different tasks the user needs the washer to perform.
TempAssure[with outer door in place]: 140°F ± 5°F (60°C ± 3°C)
TempBoost[Heated Wash/ Heated Rinse]: 145°F ± 5°F (63°C ± 3°C)
Sanitize: 150°F ± 5°F (66°C ± 3°C)
The tray rack system of the Electrolux is very user friendly. The racks have many parts that can be interchanged from top rack to bottom rack and vice versa. First we’ll look at the rolling components.
The top rack has a two part rolling feature. It has metal tracks that are slipped into the body of the dishwasher that allows the entire top rack to come forward when the user pulls on it. The second part is the wheels that are fitted into the metal track. The wheels allow the top rack to come forward past the tracks and past the body of the dishwasher. This allows for easy usage. The bottom rack is much simpler. It consists of wheels that are fitted into grooves inside the bottom of the dishwasher’s body. The grooves allow the wheels to travel along the bottom of the body and the inside of the door (when horizontal with the ground) and bring the bottom rack to an easily reachable position.
Both racks also have spokes and utensil baskets. The spokes are easily pushed either up or down to allow a custom arrangement of dishes. The utensil baskets are also simply snapped on or off. This allows for custom arrangement as well as easy unloading by the user. The utensil baskets also have silver wear flaps, for a various array of utensils.
One elite part of this dishwasher is the top rack height adjusting system. The user can raise or lower the top rack with the push of a lever. The lever moves a spring, which then applies force to tabs that hold the rack in grooves. The force on the tabs allows them to come out of the grooves and for the rack’s height to be changed. Once the rack is in position the tabs go back into their grooves and hold the rack in place.
Supporting Wiki pages
Product Dissection: Single-Use Cameras: Single-Use Cameras
Product Dissection: Bicycles: Bicycles
Engine Dissection Wiki Project ME240/107S : ME107/240 2010S
LCD TV: LCD TV_Westinghouse
ME240 Course Links
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