Washing machine

A washing machine (laundry machine, clothes washer, or washer) is a machine designed to wash laundry, such as clothing, towelsand sheets. The term is mostly applied only to machines that use water as the primary cleaning solution(SONY Vaio VGN-CR11Z/R battery), as opposed to dry cleaning (which uses alternative cleaning fluids, and is performed by specialist businesses) or even ultrasonic cleaners.

History

To clean clothing it is necessary to rub and flex the cloth to break apart solids and help the soap penetrate(SONY Vaio VGN-CR13/B battery). At first this was done by pounding or rubbing the clothing with rocks in a river, and later developed into the corrugated wash board. In Roman times a person would whiten clothing by rubbing it against a rock while letting soap lie on it. The soap was made of animal fat(SONY Vaio VGN-CR13/L battery).

Clothes washer technology developed as a way to reduce the drudgery of this scrubbing and rubbing process by providing an open basin or sealed container with paddles or fingers to automatically agitate the clothing(SONY Vaio VGN-CR13/P battery). The earliest machines were often hand-operated. As electricity was not commonly available until at least 1930, these early machines were often operated by a low-speed single-cylinder hit and miss gasoline engine(SONY Vaio VGN-CR13/R battery).

Because water usually had to be heated on a fire for washing, the warm soapy water was precious and would be reused over and over, first to wash the least soiled clothing, then to wash progressively dirtier clothing(SONY Vaio VGN-CR13/W battery). While the earliest machines were constructed from wood, later machines made of metal permitted a fire to burn below the washtub, to keep the water warm throughout the day's washing.

Removal of soap and water from the clothing after washing was originally a separate process(SONY Vaio VGN-CR13G battery). The soaking wet clothing would be formed into a roll and twisted by hand to extract water. To help reduce this labour, the wringer/mangle was developed, which uses two rollers under spring tension to squeeze water out of the clothing(SONY Vaio VGN-CR13G/B battery). Each piece of clothing would be fed through the wringer separately. The first wringers were hand-operated, but were eventually included as a powered attachment above the washer tub. The wringer would be swung over the wash tub so that extracted wash water would fall back into the tub to be reused for the next wash load(SONY Vaio VGN-CR13G/L battery).

The modern process of water removal by spinning did not come into use until electric motors were developed. Spinning requires a constant high-speed power source, and was originally done in a separate device known as an extractor(SONY Vaio VGN-CR13G/W battery). A load of washed clothing would be transferred from the wash tub to the extractor basket, and the water spun out. These early extractors were often dangerous to use since unevenly distributed loads would cause the machine to shake violently(SONY Vaio VGN-CR13G/P battery). Many efforts have been made to counteract the shaking of unstable loads, first by mounting the spinning basket on a free-floating shock-absorbing frame to absorb minor imbalances, and a bump switch to detect severe movement and stop the machine so that the load can be manually redistributed(SONY Vaio VGN-CR13G/R battery). Many modern machines are equipped with a sealed ring of liquid that works to counteract any imbalances.

What is now referred to as an automatic washer was at one time referred to as a washer/extractor, which combines the features of these two devices into a single machine, plus the ability to fill and drain water by itself(SONY Vaio VGN-CR13T/L battery). It is possible to take this a step further, to also merge the automatic washing machine and clothes dryer into a single device, but this is generally uncommon because the drying process tends to use much more energy than using two separate devices(SONY Vaio VGN-CR13T/P battery); a combined washer/dryer not only must dry the clothing, but also need to dry out the wash chamber itself.

Washing machine milestones

The first English patent under the category of Washing and Wringing Machines was issued in 1691(SONY Vaio VGN-CR13T/R battery). A drawing of an early washing machine appeared in the January 1752 issue of "The Gentlemen's Magazine," a British publication. In Germany, Jacob Christian Schäffer's washing machine design was published in 1767(SONY Vaio VGN-CR13T/W battery). In 1782 Henry Sidgier was issued a British patent for a rotating drum washer. In 1862, a patented "compound rotary washing machine, with rollers for wringing or mangling" was shown at the 1862 London Exhibition, done by Richard Lansdale of Pendleton, Manchester(SONY Vaio VGN-CR15/B battery).

The first United States Patent titled "Clothes Washing" was granted to Nathaniel Briggs of New Hampshire in 1797. Because of the Patent Office Fire of 1836, no description of the device exists, and it is not known what kind of washing device Briggs invented(SONY Vaio VGN-CR190 battery). A device that combined a washing machine with a wringer mechanism did not appear until 1843, when John E. Turnbull of Saint John, New Brunswick patented a "Clothes Washer With Wringer Rolls(SONY Vaio VGN-CR190E/L battery)."

Electric washing machines were advertised and discussed in newspapers as early as 1904. --> 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 US patent number 966677 (e.g. Woodrow's US patent number 921195) (SONY Vaio VGN-CR190E/P battery). The "inventor" of the electric washing machine remains unknown.

US electric washing machine sales reached 913,000 units in 1928. However, high unemployment rates in the Depression years hit sales; by 1932 the number of units shipped was down to about 600,000(SONY Vaio VGN-CR190E/R battery).

The first laundromat opened in Fort Worth, Texas in 1934. It was run by Andrew Clein. Patrons used coin-in-the-slot facilities to rent washing machines. The term laundromat can be found in newspapers as early as 1884 and they were widespread during the depression(SONY Vaio VGN-CR190E/W battery). It is almost impossible to determine who had the first laundromat. England established public wash rooms for laundry along with bath houses throughout the 19th century.

Washer design improved during the 1930s. The mechanism was now enclosed within a cabinet, and more attention was paid to electrical safety. Spin dryers were introduced to replace the dangerous power wringers of the day(SONY Vaio VGN-CR21/B battery).

Early automatic washing machines were usually connected to the water supply via temporary slip-on connectors to the sink taps. Later, permanent connections to both the hot and cold water supplies became the norm(SONY Vaio VGN-CR21E/L battery). Most modern front-loading European machines now only have a cold water connection (i.e. cold fill) and rely completely on electric heaters to raise the water temperature.

By 1940, 60% of the 25,000,000 wired homes in the United States had an electric washing machine(SONY Vaio VGN-CR21E/P battery). Many of these machines featured a power wringer, although built-in spin dryers were not uncommon.

Bendix introduced the first automatic washing machine in 1937, having applied for a patent in the same year. In appearance and mechanical detail, this first machine is not unlike the front loading automatic washers produced today(SONY Vaio VGN-CR21E/W battery). Although it included many of the today's basic features, the machine lacked any drum suspension and therefore had to be anchored to the floor to prevent "walking".

Many of these early automatic machines had coin-in-the-slot facilities and were installed in the basement laundry rooms of apartment houses(SONY Vaio VGN-CR21S/L battery). After the attack on Pearl Harbor, US domestic washer production had to be suspended for the duration ofWorld War II. However, many US appliance manufacturers were given permission to undertake the research and development of washers during the war years(SONY Vaio VGN-CR21S/P battery). Many took the opportunity to develop automatic machines, realizing that these represented the future for the industry.

An improved front loading automatic model, the Bendix Deluxe (which retailed at $249.50), was introduced in 1947(SONY Vaio VGN-CR21S/W battery).

General Electric also introduced its first top loading automatic model in 1947. This machine had many of the features that are incorporated into modern machines.

A large number of US manufacturers introduced competing automatic machines (mainly of the top loading type) in the late 1940s/early 1950s(SONY Vaio VGN-CR21Z/N battery). Several manufacturers even produced semi-automatic machines, where the user had to intervene at one or two points in the wash cycle. A common semi-automatic type (available from Hoover in the UK until at least the 70's) included 2 tubs(SONY Vaio VGN-CR21Z/R battery): one with an agitator or impeller for washing and/or rinsing; another, smaller, tub for water extraction or centrifugal rinsing.

One early form of automatic washing machine manufactured by Hoover used cartridges to program different wash cycles(SONY Vaio VGN-CR220E/R battery). This system, called the Keymatic, used plastic cartridges with key-like slots and ridges around the edges. The cartridge was inserted into a slot on the machine and a mechanical reader operated the machine accordingly(SONY Vaio VGN-CR23/B battery). The system did not commercially succeed because it offered no real advantage over the more conventional program dial, and the cartridges were prone to getting lost. In hindsight it can be seen as a marketing gimmick rather than offering any really useful functionality(SONY Vaio VGN-CR23/P battery).

Since their introduction in the late 1930s/mid 1940s, automatic washing machines have relied on mechanical timers to sequence the washing and extraction process. Mechanical timers consist of a series of cams on a common shaft(SONY Vaio VGN-CR23/R battery). At the appropriate time in the wash cycle, each cam actuates a switch to engage/disengage a particular part of the machinery (e.g. drain pump motor). The timer shaft is driven by a small electric motor via a reduction gearbox(SONY Vaio VGN-CR23/L battery).

On the early mechanical timers the motor ran at a constant speed throughout the wash cycle, although it was possible for the user to truncate parts of the program by manually advancing the control dial(SONY Vaio VGN-CR23/N battery). However, by the 1950s demand for greater flexibility in the wash cycle led to the introduction of electronic timers to supplement the mechanical timer. These electronic timers enable greater variation in such functions as the wash time(SONY Vaio VGN-CR23/W battery). With this arrangement, the electric timer motor is periodically switched off to permit the clothing to soak, and is only re-energised just prior to a micro-switch being engaged/disengaged.

Despite the high cost of automatic washers(Dell Latitude E5400 battery), manufacturers had difficulty in meeting the demand. Although there were material shortages during the Korean War, by 1953 automatic washing machine sales in the US exceeded those of wringer-type electric machines(Dell Latitude E6400 battery).

In the UK and in most of Europe, electric washing machines did not become popular until the 1950s. This was largely because of the economic impact of World War II on the consumer market which did not properly recover until the late 1950s(Dell Latitude E6500 battery). The early electric washers were single tub, wringer-type machines, automatic washing machines being extremely expensive. During the 1960s, twin tub machines briefly became very popular(SONY VGP-BPS10 battery), helped by the low price of the Rolls Razor washers. Automatic washing machines did not become dominant in the UK until well into the 1970s and by then were almost exclusively of the front-loader design(SONY VGP-BPL10 battery).

In early automatic washing machines, any changes in impeller/drum speed were achieved by mechanical means or by a rheostat on the motor power supply. However, since the 1970s electronic control of motor speed has become a common feature on the more expensive models(SONY VGP-BPS22A battery).

Early front loading machines, especially those manufactured in Mediterranean countries (e.g. Italy), had low spin speeds (e.g. 800 rpm or less). Nowadays, a spin speed of 1200 rpm is common and a peak spin speed as high as 1600 rpm is available on many machines(SONY VGP-BPS22/A battery). Now models in Europe have speeds of 1800 rpm and a few European washing machines have a spin speed of 2000 rpm. However, because they were not susceptible to gravitational forces, some early top loading machines had spin speeds in excess of 1000 rpm(SONY VGP-BPS18 battery), although some were as low as 360 rpm. Most US top-loading washers have spin speeds less than 1000 rpm.

In the early 1990s, upmarket machines incorporated microcontrollers for the timing process. These proved reliable, so many cheaper machines now incorporate microcontrollers, rather than mechanical timers(SONY VGP-BPS22 battery). Washing machines are a classic application for fuzzy logic. Miele, from West Germany, was the top of the line front load washer, and was introduced in Kananaskis, Alberta by Glenn Isbister starting a revolution in Laundry in Canada(SONY VGP-BPS14B Battery).

In 1994, Staber Industries released the System 2000 washing machine, which is the only top loading, horizontal-axis washer to be manufactured in the United States. The hexagonal tub spins like a front loading machine, only using about third of the water as conventional top-loaders(SONY VGP-BPS14/S Battery). This factor has led to an Energy Star rating for its high efficiency.

In 2001, Whirlpool Corporation introduced the Calypso, the first vertical-axis high efficiency washing machine to be top-loading. A washplate in the bottom of the tubnutated to bounce, shake, and toss the laundry around(SONY VGP-BPS14/B Battery). As this happened, water containing detergent was sprayed on to the laundry. The machine proved to be good at cleaning but gained a bad reputation due to frequent breakdowns and destruction of laundry and the washer was recalled with a class-action lawsuit and pulled off the market(SONY VGP-BPS14 Battery).

In the early first decade of the 21st century, the British inventor James Dyson launched the ContraRotator, 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 no longer in production(SONY VGP-BPS12 battery).

In 2007, Sanyo introduced the first drum type washing machine with ‘Air Wash’ function.[11] This washing machine uses only 50L of water in the recycle mode.

In 2008, the University of Leeds created a washing machine that uses only a cup (about 0.5 imperial pints (280 ml)) of water to carry out a full wash(SONY VGP-BPL12 battery). The machine leaves clothes virtually dry, and uses less than 2 per cent of the water and energy otherwise used by a conventional machine. As such, it could save billions of litres of water each year(SONY VGP-BPL11 battery).

Modern machines

It should be noted that while 10% of European washing machines may be top-loading they are not of the same design as North American machines. Rather than washing the clothes with an agitator, they also use a horizontally-mounted drum(SONY VGP-BPS11 battery). The clothes are loaded through a hatch in the drum wall. Their design is otherwise similar to that of a front loader. These machines may work well for small apartments as they take up less floor space than a conventional front loader(Sony Vaio VGN-FZ battery).

Top-loading

The top-loading design or V-axis clothes washer, most popular in Australia, New Zealand, Canada, the United States and Latin America, places the clothes in a vertically-mounted perforated basket that is contained within a water-retaining tub(Sony VGP-BPS8 battery), with a propeller-like agitator in the center of the bottom of the basket. Clothes are loaded through the top of the machine, which is covered with a hinged door. During the wash cycle, the outer tub is filled with water sufficient to suspend the clothing freely in the basket(Sony VGP-BPL9 battery), and the movement of the agitator pulls the clothing downward in the center towards the agitator paddles. The clothing then moves outward and up the sides of the basket to repeat the process. Top-loaders are not well-suited to cleaning large objects such as pillows or sleeping bags due to the tendency for them to just float on the surface of the water without circulating(Sony VGP-BPS9 battery), and the aggressive agitator action can damage delicate fabrics.

In most top-loading washers, if the motor spins in one direction, the gearbox drives the agitator; if the motor spins the other way, the gearbox locks the agitator and spins the basket and agitator together(Sony VGP-BPL11 battery). Similarly if the pump motor rotates one way it recirculates the sudsy water; in the other direction it pumps water from the machine during the spin cycle. Because they usually incorporate a gearbox, clutch, crank, etc(Sony VGP-BPL15 battery)., top-loading washers are mechanically more complex than front loading machines but are generally lower maintenance since there is no need for a door seal (described below). However, the electro-mechanical components in conventional top-load washers have largely reached maturity(Sony VGN-FZ460E battery).

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(Sony VGP-BPS11 battery). 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(SONY VAIO VGN-FZ4000 Battery).

Front-loading

The front-loading design or H-axis clothes washer, most popular in Europe and the Middle East, mounts the inner basket and outer tub horizontally, and loading is through a door at the front of the machine(Sony VGP-BPS10 battery). The door often but not always contains a window. Agitation is supplied by the back-and-forth rotation of the cylinder and by gravity. The clothes are lifted up by paddles on the inside wall of the drum and then dropped(Sony VGP-BPS13 battery). This motion flexes the weave of the fabric and forces water and detergent solution through the clothes load. Because the wash action does not require the clothing be freely suspended in water, only enough water is needed to moisten the fabric( Sony VGP-BPS3 battery). Because less water is required, front-loaders typically use less soap, and the aggressive dropping and folding action of the tumbling can easily produce large amounts of foam.

Front-loaders control water usage through the surface tension of water, and the capillary wicking action this creates in the fabric weave(Sony VGP-BPS2 battery). A front-loader washer always fills to the same low water level, but a large pile of dry clothing standing in water will soak up the moisture, causing the water level to drop. The washer then refills to maintain the original water level. Because it takes time for this water absorption to occur with a motionless pile of fabric(Sony Vaio VGN-FZ21M battery ), nearly all front-loaders begin the washing process by slowly tumbling the clothing under the stream of water entering and filling the drum, to rapidly saturate the clothes with water(Sony VGN-FZ150E battery).

Front-loading washers are mechanically simple compared to top-loaders, with the main motor normally being connected to the drum via a grooved pulley belt and largepulley wheel, without the need for a gearbox, clutch or crank(Sony VGN-FZ15 battery). But front-load washers suffer from their own technical problems, due to the drum lying sideways. For example, a top loading washer keeps water inside the tub merely through the force of gravity pulling down on the water(Sony VGN-FZ15L battery), while a front-loader must tightly seal the door shut with a gasket to prevent water dripping onto the floor during the wash cycle. This access door is locked shut during the entire wash cycle(Sony Vaio VGN-FZ18M battery), since opening the door with the machine in use could result in water gushing out onto the floor. For front-loaders without viewing windows on the door, it is possible to accidentally pinch fabric between the door and the drum, resulting in tearing and damage to the pinched clothing during tumbling and spinning(Sony VGN-FZ15T battery).

Nearly all front-loader washers for the consumer market must also use a folded flexible bellows assembly around the door opening, to keep clothing contained inside the basket during the tumbling wash cycle(Sony VGN-FZ480E battery). If this bellows assembly were not used, small articles of clothing such as socks could slip out of the wash basket near the door, and fall down the narrow slot between the outer tub and basket, plugging the drain and possibly jamming rotation of the inner basket(Sony VGN-FZ61B battery). Retrieving lost items from between the outer tub and inner basket can require complete disassembly of the front of the washer and pulling out the entire inner wash basket. Commercial and industrial front-loaders used by businesses (described below) usually do not use the bellows(Sony VGN-FZ31E battery), and instead require all small objects to be placed in a mesh bag to prevent loss near the basket opening.

This bellows assembly around the door is the source of problems for the consumer front-loader. The bellows has a large number of flexible folds to permit the tub to move separately from the door during the high speed extraction cycle(Sony VGN-FZ340E battery). On many machines, these folds can collect lint, dirt, and moisture, resulting in mold and mildew growth and a foul odor. Some front-loading washer operating instructions say the bellows should be wiped down monthly with a strong bleach solution(Sony VGN-FZ180E battery), while others offer a special freshening cycle where the machine is run empty with a strong dosing of bleach. In the past, suggested remedies have included adding vinegar to the laundry detergent, running an empty cycle with bleach every few weeks(Sony VGN-FZ18E battery), wiping the door gasket with a diluted bleach solution every other week, and leaving the front-loading washer door ajar between loads.

Further comparisons

Top-loading washers do not suffer from continued maintenance problems and needs no regular freshening. During the spin cycle, a top-loading tub is free to move about inside the cabinet of the machine, using only a lip around the top of the inner basket and outer tub to keep the spinning water and clothing from spraying out over the edge(Sony VGP-BPL4 battery).

There are many variations of these two general themes. 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(Sony VGN-FZ160E battery). 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(Sony VGN-FZ15M battery), but offer the efficiency of a front-loader while eliminating the problems of the flexible bellows. This kind of washing machine is sold and popular in Europe, especially in small households, because it offers the same drum system as front-loaders, just with a smaller footprint(Sony Vaio VGN-FZ18G battery).

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(Sony VGN-FZ345E battery). 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(Sony VGP-BPS14 battery). Due to the concentration of water and detergent, though, the sudsing issue of front-loaders can also be controlled by simply using less detergent without lessening cleaning action.

Tests comparing front loading and top loading machines have shown that, in general, front-loaders wash clothes more thoroughly(Sony PCGA-BP2E battery), 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(Sony VGN-FZ11S battery), 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.

Water leakage

Top loading machines are less prone to leakage. Front loading machines require a seal on the front door(Sony VGN-FZ17L battery), and similarly the front door must be latched during operation to prevent opening, lest large amounts of water spill out. This seal may leak or require replacement. Many current front-loaders, though, can be stopped and added to or removed from, by way of keeping the water level in the horizontal tub below the door level(Sony VGN-FZ17G battery).

Energy usage

Front loaders use less energy, water and detergent and clean more effectively than the best top loaders.

Water usage

Front loaders generally use less water than top-loading residential clothes washers. Estimates are front loaders use anywhere from about one third (About.com) to one half (Consumer Energy Center) as much as top loaders(Sony VGN-FZ17 battery).

Compactness

Front loading machines may be installed underneath counters. A front loading washing machine, in a fully-fitted kitchen, may even be disguised as an ordinary base cabinet/unit. They may also be convenient in homes with limited floor area, since the dryer may be installed directly above the washer(Sony VGP-BPS18 battery).

Spin-dry effectiveness

Front loaders also offer much higher spin drying speeds of up to 2000 RPM. This makes it possible to dry clothes very quickly by hanging them on washing lines or airing racks or can substantially reduce the length of time required in a tumble dryer(Sony VGP-BPS15 battery).

Noise

Front loaders tend to operate more quietly than top loaders, since there is less of a tendency to imbalance.

Accessibility and Ergonomics

Front loaders are more convenient for little people and those with paraplegia, as the controls are front-mounted and the horizontal drum eliminates the need for standing and/or climbing(Sony VGP-BPS12 battery).

For people who are sufficiently tall and can stand, top-loaders may be easier to load and unload, since reaching into the tub does not require stooping. However, this issue can be mitigated due to the offering of risers (usually with storage drawers underneath) to raise the front loader door opening closer to the user's level(Sony VGP-BPL12 battery).

Rinsing

Washing machines perform several rinses after the main wash to remove most of the detergent. Modern washing machines use less water due to environmental concerns, however this has led to the problem of poor rinsing on many washing machines on the market(Sony VGP-BPL7 battery), which can be a problem to people who are sensitive to detergents. The Allergy UK website suggests re-running the rinse cycle again.

Maintenance wash

Most, if not all consumer washing machines, now use a plastic outer shell instead of stainless steel to contain the water(Sony VGN-FZ290 battery). Washing machine manufacturers are now advising users, due to the plastic's adhesion properties with laundry detergent and mold, to perform a regular maintenance wash which cleans the inside of the washing machine(Sony VGN-FZ29VN battery). A maintenance wash is performed without any laundry on the hottest wash programme, using either one of the following: white vinegar, a detergent with bleaching properties (it is not advisable to put actual bleach inside the washing machine!) (Sony VGN-SZ56 battery) or you could use a proprietary washing machine cleaner. The purpose of a maintenance wash is to remove any mold, bacteria, old detergent residue and gunge. If using white vinegar, it is important to allow the washing machine to fill for about 30 seconds before adding the vinegar, as the first bit of water goes into the sump(Sony VGN-SZ55 battery).

European standards

Capacity and cost are the main considerations when purchasing a washing machine. If intended for use by a small family, a capacity of under 5 kg should be sufficient (thus saving energy and running costs) (Sony VGN-FZ220E battery).

Washing machines display an EU Energy Label with grades for energy efficiency, washing performance and spin efficiency. Grades run from A to G (best to worst), providing a simple method for judging running costs and performance(Sony VGN-FZ11Z battery). For example a "Triple A" (AAA) rated machine indicates lowest energy consumption, best wash and best water extraction (i.e. spin) performance. This has had the desired effect of driving customers toward more efficient washing machines and away from less efficient ones(Sony VGN-FZ11M battery).

One important factor that is missing from the energy labelling scheme is the washing machine's rinsing performance, which can adversely affect allergy sufferers and people who are sensitive to laundry detergents and chemicals(Sony Vaio VGN-FZ31M battery). It is advisable to check an independent consumer report on how well a washing machine can rinse before purchasing, as newer washing machines use a lot less water than older ones.

United States standards

Top-loading and front-loading clothes washers are covered by a single Federal Standard regulating energy consumption(Sony Vaio VGN-FZ31Z battery). The Federal Standard effective up until January 1, 2011 includes no restriction on water consumption. Therefore, washer manufacturers face no legal restriction on how much unheated rinse water may be used, in washers manufactured before that date(Sony VGN-FZ19VN battery).

Many US-market clothes washers are more energy-efficient and water-efficient than required by the mandatory Federal Standard, or even the more stringent Energy Star standard. Manufacturers may be motivated to exceed legally-mandated standards by a program of direct-to-manufacturer tax credits(Sony Vaio VGN-FZ38M battery). Excessive energy conservation in the laundering process may lead to less-than-satisfactory cleaning, and excessive water conservation may lead to poor rinsing.

Commercial washing machine

A commercial washing machine is intended for more frequent and long-term usage than a consumer washing machine(Sony Vaio VGN-FZ31S battery). Because function is more important than style, most commercial washers have a sharp-edged square appearance, often with stainless steel exteriors to minimize rust and corrosion in a constantly moist environment(Sony VGN-FZ11L battery). They are built with large easy-to-open service covers, and the washer mechanisms are internally laid out in a manner that does not require access to the underside of the unit for service(Sony VGN-FZ15G battery). Often commercial washers are installed in long rows with a wide access passageway behind all the machines to allow maintenance without moving the heavy machine.

Many commercial washers are built for use by the general public, and are installed in publicly accessible laundromats or laundrettes(Sony VGP-BPS9/B battery), operated by money accepting devices or card readers. The features of a commercial laundromat washer are more limited than a consumer washer, offering just two or three basic wash types plus an option to choose wash cycle temperatures(Sony VGN-FZ190 battery). The common front-loading commercial washing machine also differs from consumer models in its expulsion of wash and rinse water. While the consumer models pump used water out allowing the waste line to be located above the washer, front loading, commercial machines generally use gravity to expel used water(Sony VGN-FZ190E battery). A drain in the rear, at the bottom of the machine opens at the appointed time during the cycle and water flows out. This creates the need for a trough behind machines which leads to a filter and drain(Sony VGN-FZ18 battery). the trough is usually part of a cement platform built for the purpose of raising the machines and can be seen behind washers at most laundromats.

Commercial washers for business (still often referred to as a washer/extractor) can include extra features that are never seen in the consumer market(Sony Vaio VGN-FZ21E battery ). Many commercial washers offer an option for automatic chemical injection of five or more different chemical types, so that the operator does not have to deal with constantly measuring out soap products and fabric softeners for each load(Sony Vaio VGN-FZ21S battery). Instead a precise metering system draws the detergents and wash additives directly from large liquid-chemical storage barrels and injects them as needed into the various wash and rinse cycles(Sony VGN-FZ230E battery).

Some computer-controlled commercial washers offer the operator complete control over the various wash and rinse cycles, allowing the operator to program custom washing cycles(Sony Vaio VGN-FZ210CE battery).

One special type of continuous-processing washer is known as the tunnel washer which does not have separate, distinct wash or rinse cycles, but combines them all in sequence inside a single long large-diameter rotating tube(Sony Vaio VGN-FZ18S battery).

Industrial washing machines

An industrial clothes washer can be used to batch process up to 300 pounds (140 kg) of textiles at once, and can be used for extremely machine-abusive washing tasks such as stone washing or fabric bleaching and dyeing(Sony VGN-FW11 battery).

An industrial washer can be mounted on heavy shock absorbers and attached to a concrete floor so that it can extract water from even the most severely out-of-balance and heavy wash loads. It may be mounted on hydraulic cylinders(Sony VGN-FW11M battery), permitting the entire washer to be lifted and tilted so that fabrics can be automatically dumped from the wash drum onto a conveyor belt once the cycle is complete(Sony VGN-FZ18L battery).

Washing machine manufacturers

Alliance Laundry (Speed Queen)

Amica

Antonio Merloni under the brand names Asko, Ardo, Philco and Servis

Arçelik - including the brand names Beko, Blomberg, Altus and Arctic

Bendix

Bosch - including the brand names Siemens, Neff, Balay, Profilo and Constructa

Candy - including the brand names Hoover and Zerowatt(Sony Vaio VGN-FZ31B battery)

Continental Girbau

Dexter Laundry

Dyson (no longer produced)

Electrolux - including the brand names AEG, Frigidaire, John Lewis, Rex, Tricity Bendix, Zanussi and Zoppas

Fagor - including the brand names Brandt, Thompson, Ocean and SanGiorgio

Fisher & Paykel

GE - including (in the United States) the brand name Hotpoint

Godrej (India) (Sony VGN-FZ145E battery)

Gorenje

Haier

Hitachi

IFB

Indesit - including the brand names Hotpoint-Ariston, Creda and Scholtes

LG

Mabe - including the brand names Easy, Centrales, Dako, Moffat

Miele

Mueller Eletrodomésticos

Pellerin Milnor

Samsung

Schulthess - including the brand name Merker

Smeg

Staber

Thor

V-Zug - including the brand names Sibir and Gehrig

Vestel

Videocon (India)

Washex

Whirlpool - including the brand names Admiral, Amana, Inglis, Kenmore, Maytag, Magic Chef, Estate, Kirkland and Roper(Sony Vaio VGN-FZ31J battery )

Role in women's liberation

The historically laborious process of washing clothes has at times been labelled "woman's work" and women from all classes tried to find ways to get relief from doing laundry.

In 2009, L'Osservatore Romano published an article entitled "The Washing Machine and the Liberation of Women" that was controversially meant to demonstrate that the washing machine had done more for the liberation of woman than the contraceptive pill and abortion rights(Sony Vaio VGN-FZ21J battery), which are often associated to Women's Day. The article shocked Italian feminists and provoked criticism from Opposition MP Paola Concia. A study from Université de Montréal also presented a similar point of view to that of L'Osservatore(Sony VGN-FZ340E/B battery).