Dishwasher

● Fills itself with water

● Heats the water to the appropriate temperature

● Automatically opens the detergent dispenser at the right time

● Shoots the water through jets to get the dishes clean

● Drains the dirty water

● Sprays more water on the dishes to rinse them

● Drains itself again

● Heats the air to dry the dishes off, if the user has selected that setting

Purpose

-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

Contributor

Dr. Simpson

Institution

The Pennsylvania State University

Activity Classification

The table of Activity Classification for the course

Teaching Materials

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 invented the 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.

Figure 1: The First Dishwasher (Table Furniture Cleaning Machine) (Source: US Patent No. 7365, dated May 14, 1850)

How a dishwasher functions

Dishwashers Classification

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.