DishwasherA dishwasher: is a mechanical device for cleaning dishes and eating utensils. Dishwashers can be found in restaurants and private homes. Unlike manual dishwashing, which relies largely on physical scrubbing to remove soiling, the mechanical dishwasher cleans by spraying hot water, typically in between 55 to 75 C (130to 170F) at the dishes, with lower temperatures used for delicate items. A mix of water and detergent is used for cleaning purposes, followed by clean water to remove the detergent residue. Some dishwashers have multiple wash and rinse periods within the complete cycle. In some dishwashers, a rinsing aid (also called rinse aid) can be added to the rinse cycle to improve drying and avoid water spots remaining on dry items.

Inside Dishwasher:Although dishwashers are watertight, they don't actually fill with water. Just a small basin at the bottom fills up. There, heating elements heat the water to 130 to 140 degrees Fahrenheit. Then a pump propels the water up to the water jets, where it is forced out and sprayed against the dirty dishes. Think about a garden hose with no nozzle - if you put your thumb over the end of the hose, decreasing the space for the water to come out, it sprays out more forcefully. The dishwasher's jets work on the same principle. The force of the water also makes the arms that hold the spray jets rotate, just like a lawn sprinkler. When the washing and rinsing is finished, the water drains down to the basin again, where the pump propels the water out of the dishwasher. Depending on the type of dishwasher, the drain water might go right into the pipes under your sink, or travel up a hose into your sink itself. The final step in a wash cycle is optional - the dry cycle. The heating element at the bottom of the dishwasher heats the air inside to help the dishes dry. Some people just let them dry without heat to save energy.In addition, dishwashers monitor themselves to make sure everything is running properly. A timer (or a small computer) regulates the length of each cycle. A sensor detects the water and air temperature to prevent the dishwasher from overheating or damaging your dishes. Another sensor can tell if the water level gets too high and activates the draining function to keep the dishwasher from overflowing. Some dishwashers even have sensors that can detect the dirtiness of the water coming off the dishes. When the water is clear enough, the dishwasher knows the dishes are clean.History of Dishwasher:The first reports of a mechanical dishwashing device are of an 1850 patent in theUnited Statesby Joel Houghton for a hand-powered device. This device was made of wood and was cranked by hand while water sprayed onto the dishes. This device was both slow and unreliable. Another patent was granted toL.A. Alexanderin 1865 that was similar to the first but featured a hand-cranked rack system. Neither device was practical or widely accepted. Modern dishwashers are descended from the 1887 invention ofJosephine Cochranewho invented a new advanced dishwasher, also hand-powered, which she unveiled at the 1893ChicagoWorld's Fair. Cochrane was quite wealthy and was the granddaughter ofJohn Fitch, the inventor of thesteamboat. She never washed dishes herself and invented the dishwasher because her servants were chipping her fine china.Models installed with permanentplumbingarrived in the 1920s. InEnglandin 1924,William Howard Livensinvented a small dishwasher suitable for domestic use. It had many of the features of a modern dishwasher, including a front door for loading, a wire rack to hold crockery and a rotating sprayer.Livens' invention was not, however, a commercial success. Electric drying elements were added in 1940.Initially home appliances were standalone or portable devices in a kitchen, along with other sinks and the water heater, but with the development of the wall-to-wallcountertopand standardized height cabinets, dishwashers evolved into standardized size and shape appliances first integrated with the sink, and then underneath the kitchen countertop as a modular unit.Adoption was greatest at first in commercial environments, but by the 1970s dishwashers had become commonplace in domestic residences in the US. By 2005, 60 percent of US homes had dishwashers.

Types of dishwashers: Built-in standard dishwashers:These models are standard fare. They take up permanent space in your kitchen and are built in with a drop-down hinged door. They now come in stainless steel or can blend into your cabinetry style. Most standard-size dishwashers take about 2.4 gallons of water to wash a load.Price: $250 to $1,600Who it's best for:People who have room in their kitchens, wash large loads of dishes, and want the standard pull-out dish racksAverage size: Width: around 24 to 30 inches; depth: around 25 inches; height: around 34 inch. Compact dishwashersWhether you need a small dishwasher for your apartment or RV, compact dishwashers offer many of the same features as basic standard models but are simply smaller. They can hold around eight place settings. Price: $350Who it's best for: People with limited cabinet spaceAverage size: Width: 18 inches; depth: 22.5 inches; height: 32.50 inches In-sink dishwashersThis dishwasher literally fits inside your sink. It handles small loads quickly--like dirty glasses during a cocktail party--and it can also act as extra counter space or a cutting board because its top becomes a flat stainless steel surface in most cases. Because the loads are smaller, these models use less water.Price: $1,800Who it's best for: People with big budgets who do small loads of dishes and have limited cabinet spaceAverage size: Width: 34.5 inches; depth: 22 inches; height: 21 inches.

Drawer dishwashersThis dishwasher literally fits inside your sink. It handles small loads quickly--like dirty glasses during a cocktail party--and it can also act as extra counter space or a cutting board because its top becomes a flat stainless steel surface in most cases. Because the loads are smaller, these models use less water.Price: One drawer: $700; two drawers: $1,200Who it's best for: People who want extra dish storage and energy efficiencyAverage size: Width: 23.5 inches; depth: 22.5 inches; Height: around 16 inches; Portable dishwashersThese compact- or standard-size dishwashers don't have to take up permanent space in your kitchen. Some even come in a countertop version that hooks up to your faucet and look like a microwave.Price: $400 to $600Who it's best for: Renters or homeowners who don't have room for a built-in model Average size: Width: around 24 inches; depth: 28 inches; height: around 36 inches Working of Components of Dishwasher:All dishwashers work in pretty much the same way. To understand how they work, let's look at these three areas:1. The motor and pump systemYour dishwasher has at least one motor. It is attached to a pump, which forces the water up into the sprayer arms. During the drain cycle, it also pushes the water out of the dishwasherdown the drain. A few European dishwashers use two separate motors, one for spraying and one for draining.The motor is behind an access panel beneath the dishwasher. Some models have reversible motors, others don't. We will also discuss two older types that are not used in the newer dishwashers.If the motor is reversible, it is mounted vertically right in the center bottom of the dishwasher with the motor shaft pointed up. The pump is mounted atop the motor, then attached to the underside of the dishwasher. When the motor runs one way, the dishwasher pumps water up to the spray arms; when it runs the other way, it drains the water.If the motor rotates in a single direction, it is mounted horizontally, with the motor shaft pointed sideways, near the center bottom of the dishwasher. The pump is mounted to the end of the motor. The top of the pump is then mounted to the underside of the dishwasher. When the motor runs, it pumps water to the spray arms. To pump water to the drain, a mechanical arm integrated with the pump and motor activates, which diverts the water to the drain.Two other, older systems are becoming "extinct," in that they are no longer made.One is a belt-driven system. Its motor is near the front right corner of the dishwasher. The pump is mounted to the underside of the dishwasher at the center, and a tube-shaped belt connects the motor and pump. The motor is reversible: when the motor runs one way, the unit pumps water to the spray arms. When it runs the other way, the motor drives the pump to push the water out to the drain.The other system's motor rotates in only one direction. It's mounted vertically, right in the center bottom of the dishwasher, with the shaft of the motor pointed up, with the pump mounted atop the motor. The pump is then attached to the underside of the dishwasher. When the motor runs, it pumps water to the spray arms. To pump water out to the drain, a valve, completely separate from the pump and motor is activated. It diverts the water to the drain.

2. The controls, switches, valves, and solenoidsA dishwasher has at least three, but often six or more controls, switches, valves and solenoids. We will discuss these: Timer:Dishwashers have a timer behind the main control panel at the front top of the dishwasher, or behind the lower access panel. It is either a mechanical device like a simple clock, or it's completely electronic with just a digital readout. The timer runs the dishwasher in a pre-determined pattern. It provides the electricity to all of the dishwasher components at the correct time, for the correct length of time. Selector switch:A dishwasher usually has one or more selector switches on the main control panel at the top front of the door. The switch(es) allow you to choose among wash cycles, drying cycles (heat or no heat), temperature of the wash or rinse, and so on. The switches tell the timer which cycle options to engage. Water-inlet valve:At the bottom left or right of the dishwasher, there's a water-inlet valve behind the access panel. This valve lets water flow into the dishwasher for the wash cycle. It is usually attached to the hot-water supply line, and to a tube that is then attached to the left or right side of the dishwasher. When the timer sends electricity to the valve, it opens and lets water into the dishwasher. The valve stops when the water level trips the float switch or when the timer stops sending electricity to the valve.

Float switch:Dishwashers have something meant to keep them from overfilling. This is usually a small switch attached to a float--a float switch. The float, which is usually cylindrical, is inside the dishwasher at the bottom, usually on the left side. As the water level in the dishwasher rises, the float rises too. When it reaches a certain height, the float activates its switch, which cuts the electricity to the water inlet valve. If the water-inlet valve is defective, the dishwasher may overfill. Soap dispenser:Dishwashers have a soap dispenser located on the inside of the door. When the timer cycle calls for the soap to be emptied into the dishwasher, it either sends electricity to a bi-metal switch that opens it, or it mechanically opens the soap dish. Rinse aid dispenser:Some dishwashers have a rinse-aid dispenser on the inside of the door. When the timer cycle calls for the rinse aid to be emptied into the dishwasher, it sends electricity to a solenoid switch, which opens the dispenser and measures rinse aid into the dishwasher. Drain solenoid:Beneath some dishwashers, there's a timer-activated drain solenoid (an electro-magnetic coil) that opens a drain valve, to drain the wash water through a hose and out to the house's plumbing waste system. Thermostat:Dishwashers have one or more small, cylindrical thermostats. These are a bit larger in diameter than a dime and have two or more wires attached to them. They protect the dishwasher, dishes, and humans by turning off the heating element that heats the water or the air in the dishwasher when it has reached its pre-set temperature. The thermostat automatically re-sets when the temperature falls to a lower level. Soil sensors:Many of the more-recent dishwashers use multi-component soil sensors, which continually monitor the wash water during the wash cycle. These sensors help the dishwasher to wash for the amount of time that is appropriate for how dirty the dishes are, rather than for a pre-set period. When the water becomes clear enough, the sensor signals the timer to continue with the next cycle. Door switch:Dishwashers have a door (or door interlock) switch that--if properly functioning--shuts off the dishwasher when the door is open. Drying fan:Some dishwashers use a small fan to blow air (or heated air) into the dishwasher to dry the dishes faster. If your machine has a drying fan, it's beneath the dishwasher, usually in the back right corner. Heating element:Dishwashers have at least one heating element--which is often a circular black tube at the bottom of the dishwasher under the lower spray arm. The element usually assists in heating the wash and rinse water to the proper temperature and/or assists in drying the dishes. Some dishwashers have another heating element integrated with the drying fan, to warm the air blown into the dishwasher to dry the dishes.

3. The interior:The interior of a dishwasher is where the dishes go. It contains the dish racks, the spray arms, and/or the tower that sprays water at the dishes, the upper part of the pump assembly, and the water filter.

Labeled Diagram of Dishwasher:

Dishwasher Parts:These are the different parts of dishwasher machine. These parts can be replaced and installed in machine if one of them parts is damaged or stops working. These parts can easily be purchased from market.

Dishrack Roller Axle:Item # 1460970Price: $1.00

Dishrack RollerItem # 943425Price: $1.40

Tine ClipItem # 1042060Price: $1.20

Latch AssemblyItem # 1266679Price: $22.70

LG Dishwasher Models:Lds4821ST & LDS4821BBFeatures: These two units are energy star qualified and need the standards of natural resources. Its you will be able to save energy and water. These two models have built-in large tub that offers a large space. The 16 place settings allow you to wash more dishes at once. So you can save energy and time also. The sense clean wash system uses a sensor that that measures the level of dirt in the wash water and then adjusts the cycle accordingly. This feature provides water and energy efficiency.Advantages: Both dishwashing models have a sleek exterior, which makes them a modern addition to your kitchen. The LoDecible feature is a great advantage of the dishwasher, because it provides superior noise insulation, so you will experience minimal noise in the kitchen. The energy star qualification is another advantage of dishwasher that will allow you to save energy, water and money. The control panel of both the dishwashers is easy to use. The 5 wash cycles offer you the possibility to select the cycle according to your needs. The built-in large tub is also a large advantage because it offer you a large capacity for dishes.Conclusion:It is concluded that dishwasher machine is a very useful machine. It can help us in kitchen work. I can also say that this is an electronic robot that helps us in kitchen works. This machine not only helps us, it saves our time also. This also saves energy, money and water.

References http://www.repairclinic.com/Dishwasher-How-Things-Work http://home.howstuffworks.com/dishwasher.htm http://www.repairclinic.com/Dishwasher-Built-In-Appliance-Diagram http://www.repairclinic.com/Dishwasher-Parts http://www.pcappliancerepair.com/category.php?cat=3&man_id=2&sub_id=80 http://www.dishwashers-reviews.info/lg-lds4821st-and-lg-lds4821bb/ http://reviews.cnet.com/dishwashers/ http://www.energystar.gov/index.cfm?fuseaction=find_a_product.showProductGroup&pgw_code=DWs