Washing machine

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This article is about the laundry-cleaning apparatus. For the Sonic Youth album, see Washing Machine.

A washing machine is a machine designed to clean laundry, such as clothing, towels and sheets. The term is generally applied only to machines that use water as the primary cleaning solution, as opposed to dry cleaning (which uses alternative cleaning fluids, and is generally performed by specialist businesses) or even ultrasonic cleaners.

1 History
2 Modern machines
- 2.1 Washing / Drying machine
- 2.2 European Standards
3 See also
4 External links

[edit] History

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The first British patent under the category of Washing and Wringing Machines was issued in 1691. A drawing of an early washing machine appeared in the January 1752 issue of "The Gentlemen's Magazine," an English publication. In 1782 Henry Sidgier was issued a British patent for a rotating drum washer.

The first United States Patent titled "Clothes Washing" was granted to Nathaniel Briggs of New Hampshire in 1797. Fire destroyed the patent office and no description of the device exists so it is not known what kind of washing device Briggs "invented."

The electric washing machine was first mass produced in 1906. It is not known who first invented the electric washer. Alva.J. Fisher has been incorrectly credited with the invention of the electric washer. The US patent office shows at least one patent issued before Mr. Fisher's. ^{[citation needed]}

[edit] Modern machines

Washing machines are available in two main configurations: "top loading" and "front loading". The "top loading" design, most popular in the United States, Canada, Australia and some 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. "Top loading" machines in Asia use impellers instead of agitators. Impellers are similar to agitators except that they do not have the center post extending up in the middle of the wash tub basket. Clothes are loaded through the top of the machine, which is covered with a hinged door.

The "front loading" design, most popular in Europe and the Middle East, mounts the cylinder horizontally, and loading is through a glass door at the front of the machine. The cylinder is also called the drum. Agitation is supplied by the back-and-forth rotation of the cylinder and by gravity. The clothes are lifted up by paddles in the drum and then dropped. This motion flexes the weave of the fabric and forces water and detergent solution through the clothes load. Although rarer, there is also a variant of the horizontal axis design that is loaded from the top, through a small door in the circumference of the drum. These machines usually have a shorter cylinder and are therefore smaller.

Image:70s laundromat.jpg All washing machines work by using mechanical energy, thermal energy, and chemical action. Mechanical energy is imparted to the clothes load by the rotation of the agitator in top loaders, or by the tumbling action of the drum in front loaders. Thermal energy is supplied by the temperature of the wash bath. Many front loading machines have electrical heating elements to heat the wash bath to near boiling. Chemical action is supplied by the detergent and other laundry chemicals. Front loaders use special detergents that are designed to release different chemical ingredients at different temperatures. This is so that different type of stains and soils will be cleaned from the clothes as the wash water is heated up by the electrical heater. Front loaders also need to use low sudsing detergents because the tumbling action of the drum folds air into the clothes load that can cause over sudsing.

Tests comparing front loading and top loading machines have shown that, in general, front-loaders wash clothes more thoroughly, cause less wear, and use less water and energy than top-loaders. As a result of using less water, they require less detergent to be used, or conversely, they can use the same amount of detergent with less water, which increases detergent concentration and increases the amount of chemical action. They also allow a dryer to be more easily mounted directly above the washer. Image:Waschvollautomat Constructa 1950er.jpg

Top-loaders have the advantage that they complete a washing cycle 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). They also tend to be easier to load and unload, since reaching into the tub does not require stooping. The top loader's spin cycle between washing and rinsing allows an extremely simple fabric softener dispenser, which operates passively through centrifugal force and gravity. The same objective must be accomplished by a solenoid-operated valve on a front loader. Another advantage to the top-loading design is the reliance on gravity to contain the water, rather than potentially trouble-prone or short-lived front door seals.

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, however this machine is not currently in production.

[edit] Washing / Drying machine

Usually known as a "combo" or "combination washer/dryer", this is an appliance which performs both washing and drying functions to remove the loading and unloading clothes from one machine to another.

The engineering goals in the design and construction of a washing machine or a dryer are opposites, since one machine adds water to the laundry and the other removes it. During the wash cycle, the large drying fan, ducting and heating elements must all be protected from water. During the drying cycle, watertight rubber seals must not be damaged by heat. And in all cases, the complexity of the mechanism within the confines of a cabinet which will be maneoverable through standard doorways, will limit the volume of the drum and therefore quantity of laundry which may be washed.

A clothes dryer should be of the front-loading design; a top-loading dryer would not tumble wet clothing at the bottom of the drum. A combo unit is therefore forced to have a horizontal drum, even though front-loading washers have traditionally (until about 2000) been unpopular in North America usually due to cost reasons.^{[citation needed]}

Another problem with some such machines is that only half of the laundry can be dried after the washing process is complete, because drying requires more drum volume for a given load. However, by intelligently controlling the drying temperature and drum speed, most washer/dryers are capable of performing both functions in a single machine without interruption and with the full laundry load.

[edit] European Standards

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Capacity and cost are the main considerations when purchasing a washing machine. If intended for use by a single person, a capacity of under 5Kg should be sufficient (thus saving energy and running costs).

Washing machines are given Eurobell grades for washing performance, energy efficiency and spin efficiency. Grades run from A to E (best to worst), and provide a simple method for judging running costs and performance. An AAA machine will denote top performance in the three categories.