Washing machine

A washing machine is a machine designed to assist in the cleaning of laundry, i.e. clothing and other household textile such as towels and sheets. It is generally restricted to machines that use water as the primary cleaning solution, as distinct from dry cleaning which uses alternative cleaning fluids and is generally performed by specialist businesses.

Front-loading washing machine.
Larger version

Mechanical washing machines have been available since at least the 19th century, and their basic principles of operation have remained largely unchanged. Their first purpose is to suspend the material to be cleaned in water contaning detergent. The clothes and water are then "agitated" - moved back and forth in a chaotic manner. The water is then pumped out and the clothes partially dried by spinning them rapidly in a low-speed centrifuge. Clean water is then added and the clothes and water agitated to remove any remaining traces of the detergent. Finally, the clothes are (usually) spun again (though some clothes are removed immediately and dried by alternative means without further spinning).

Virtually all contemporary washing machines are powered by electricity, though hand-powered or even steam-powered machines were common in earlier times. They are almost universal in wealthier countries, though some people living in smaller apartments do not have room for them and use communal launderettes[?].

Contemporary washing machines are available in two main configurations - "top loading" and "front loading". The "top loading" design, the most popular in the United States and parts of Europe , places the clothes in a vertically-mounted cylinder, with a propeller-like agitator in the center of the bottom of the cylinder. Clothes are loaded at the top of the machine, which is covered with a hinged door. The "front loading" design most popular in the UK instead mounts the cylinder horizontally, with loading through a glass door at the front of the machine. Agitation is supplied by the actual back-and-forth rotation of the cylinder. The cylinder is also called the drum.

Tests comparing front-loading and top-loading machines empirically have shown that, in general, front-loaders wash clothes more thoroughly, cause less wear, and use less water and energy than top-loaders. They also allow a dryer[?] to be mounted directly above the washer, impossible with a top-loader. Top-loaders do have the advantages that they complete washing much faster, tend to cost less for the same capacity machine, and allow clothes to be removed at intermediate stages of the cycle (for instance, if some clothes within a wash are not to be spun.

In the late 1990s, the British inventor James Dyson[?] launched a type of washing machine with two cylinders rotating in opposite directions; which, it is claimed, reduces the wash time and produces cleaner results.

See also