Product Dissection: Dishwasher
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
-To explore how a dishwasher works and to see the differences between dishwashers from different manufacturers.
-Freshman or sophomore level students of all engineering majors
The Pennsylvania State University
The table of Activity Classification for the course
|Cross-Cutting Concepts||Congnitive Dimension||Tech Topic Area - Engineering|
|○ Systems||● Knowledge||○ Medical|
|● Design||○ Capabilities||○ Engergy & Power|
|○ Info Tech & Comm|
|○ Connections||○ Decision-making||○ Transfortation|
|● Manufacturing & Const|
General teaching Materials
Supporting Wiki pages: Electrolux_Dishwasher
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.
How a dishwasher functions
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 majority of the 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 be used for other purposes while dishwasher is running. These dishwashers do require a plumbing installation to waterworks. Because of the standard width of dishwashers being 24 inch, 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 a 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 number of available 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.