Vacuum cleaner

A vacuum cleaner, commonly referred to as a vacuum is a device that uses an air pump to create a partial vacuum to suck up dust and dirt, usually from floors, and optionally from other surfaces as well(SONY VGP-BPS8 battery). The dirt is collected by either a dustbag or a cyclone for later disposal. Vacuum cleaners, which are used in homes as well as inindustry, exist in a variety of sizes and models: from small battery-operated hand-held devices, huge stationary industrial appliances that can handle several hundred litres of dust before being emptied(SONY VAIO VGN-FZ Battery), and self-propelled vacuum trucks for recovery of large spills or removal of contaminated soil.

History

The vacuum cleaner evolved from the carpet sweeper via manual vacuum cleaners. The first manual models, using bellows, came in the 1860s, and the first motorised models came in the beginning of the 20th century(SONY VAIO VGN-FZ11S Battery).

Daniel Hess

Daniel Hess of West Union, Iowa, USA invented a vacuum cleaner in 1860. Calling it a carpet sweeper instead of a vacuum cleaner, his machine did, in fact, have a rotating brush like a traditional vacuum cleaner, and also possessed an elaborate bellows mechanism on top of the body to generate suction of dust and dirt(SONY vgp-bps9 battery). Hess received a patent (U.S. No. 29.077) for his invention of the vacuum cleaner on July 10, 1860.

Ives W. McGaffey

The first manually-powered cleaner using vacuum principles was the "Whirlwind," invented in Chicago, USA in 1868 by Ives W. McGaffey(sony vgp-bpl9 battery). The machine was lightweight and compact, but was difficult to operate because of the need to turn a hand crank at the same time as pushing it across the floor. McGaffey enlisted the help of The American Carpet Cleaning Co. of Boston to market it to the public. It was sold for $25(SONY VAIO VGN-FZ32 Battery). It is hard to determine how successful the Whirlwind was, as most of them were sold in Chicago and Boston, and it is likely that many were lost in the Great Chicago Fire of 1871. Only two are known to have survived, one of which can be found in the Hoover Historical Center(SONY VAIO VGN-FZ440N Battery).

McGaffey was but one of many 19th-century inventors in the United States and Europe who devised manual vacuum cleaners. He obtained a patent (U.S. No. 91,145) on June 8, 1869(SONY VAIO VGN-FZ280E Battery).

Melville Bissell

In 1876, Melville Bissell of Grand Rapids, Michigan, USA created a vacuum cleaner for his wife, Anna, to clean up sawdust in carpeting. Shortly after, Bissell Carpet Sweepers were born. After Melville died unexpectedly in 1889, Anna took control of the company and was one of the most powerful businesswomen of the day(SONY VAIO VGN-FZ460E Battery).

John S. Thurman

On November 14, 1898, John S. Thurman of St. Louis, Missouri, USA. submitted for patent (U.S. No. 634,042) a "pneumatic carpet renovator". It was issued on October 3, 1899.[5] Thurman created a gasoline powered carpet cleaner for the General Compressed Air Company. In a newspaper advertisement from the St. Louis Dispatch, Thurman offered his invention of the horse drawn (SONY VAIO VGN-FZ190 Battery) (which went door to door) motorized cleaning system in St. Louis. He offered cleaning services at $4 per visit. By 1906, Thurman was offering built-in central cleaning systems that used compressed air, yet featured no dust collection(SONY VAIO VGN-FZ150E Battery). Thurman's machine is sometimes considered the first vacuum cleaner. However, the dust was blown into a receptacle rather than being sucked in, as in the machine now used. In later patent litigation, Judge Augustus Handruled that Thurman "does not appear to have attempted to design a vacuum cleaner, or to have understood the process of vacuum cleaning." (SONY VAIO VGN-FZ260E Battery)

H. Cecil Booth

Hubert Cecil Booth has the strongest claim to inventing the motorized vacuum cleaner in 1901. As Booth recalled decades later, in 1901 he attended “a demonstration of an American machine by its inventor” at the Empire Music Hall in London. The inventor is not named(SONY VAIO VGN-FZ140E Battery), but Booth’s description of the machine conforms fairly closely to Thurman’s design, as modified in later patents. Booth watched a demonstration of the device which blew dust off the chairs, and thought it would be much more useful to have one that sucked dust. He tested the idea by laying a handkerchief on the seat of a restaurant chair, putting his mouth to the handkerchief, and then trying to suck up as much dust as he could onto the handkerchief(SONY VAIO VGN-FZ11l Battery). Upon seeing the dust and dirt collected on the underside of the handkerchief he realized the idea could work.

Booth created a large device, driven first by an oil engine, and later by an electric motor. Nicknamed the "Puffing Billy", Booth's petrol-powered(SONY VAIO VGN-FZ11z Battery), horse-drawn vacuum cleaner relied upon air drawn through a cloth filter. Gaining the royal seal of approval, Booth's motorized vacuum cleaner was used to clean the carpets of Westminster Abbey prior to Edward VII's coronation in 1901. Booth received his first patents on February 18 and August 30, 1901(SONY VAIO VGN-FZ11m Battery).

Booth started the British Vacuum Cleaner Company and refined his invention over the next several decades. Though his "Goblin" model lost out to competition from Hoover in the household vacuum market, his company successfully turned its focus to the industrial market, building ever-larger models for factories and warehouses(SONY VAIO VGN-FZ18m Battery). Booth's company, now BVC, lives on today as a unit of pneumatic tube system maker Quirepace Ltd.

Booth gave the vacuum cleaner its start. His first vacuum cleaner, called "puffin' Billy," was made of a piston pump. It did not contain any brushes; all the cleaning was done by suction through long tubes with nozzles on the ends. It was a large machine, mounted in a horse-drawn van that was pulled through the streets(SONY VAIO VGN-FZ21m Battery). The vans of the British Vacuum Cleaning Company (BVCC) were bright red; uniformed operators would haul hose off the van and route it through the windows of a building to reach all the rooms inside(SONY VAIO VGN-FZ410 Battery). Booth was harassed by complaints about the noise of his vacuum machines and was even fined for frightening horses. The BVCC's most prestigious engagement was cleaning the carpets in Westminster Abbey in London before the 1901 coronation of King Edward VII and Queen Alexandra(SONY VAIO VGN-FZ21 Battery).

David T. Kenney

Nine patents granted to the New Jersey, USA inventor David T. Kenney between 1903 and 1913 established the foundation for the American vacuum cleaner industry. Membership in the Vacuum Cleaner Manufacturers' Association, formed in 1919, was limited to licensees under his patents(SONY VAIO VGN-FZ160 Battery).

Walter Griffiths

In 1905 "Griffith's Improved Vacuum Apparatus for Removing Dust from Carpets" was another manually operated cleaner, patented by Walter Griffiths Manufacturer, Birmingham, England. It was portable, easy to store, and powered by "any one person (such as the ordinary domestic servant) (SONY VAIO VGN-FZ210CE Battery)," who would have the task of compressing a bellows-like contraption to suck up dust through a removable, flexible pipe, to which a variety of shaped nozzles could be attached. This was arguably the first domestic vacuum-cleaning device to resemble the modern vacuum cleaner(SONY VAIO VGN-FZ38M Battery).

Hermann Bogenschild

German immigrant engineer Hermann Bogenschild filed a patent in 1906 for a mechanical 'dust removing apparatus.' Emigrating from Berlin to Milwaukee in 1892, Bogenschild's device was mounted on wheels for portability and its motor was connected to a hose and filter system(SONY VAIO VGN-FZ31z Battery).

James Murray Spangler

In 1907, James Murray Spangler, a janitor from Canton, Ohio, USA invented the first practical, portable vacuum cleaner. Crucially, in addition to suction that used an electric fan, a box, and one of his wife's pillowcases, Spangler's design incorporated a rotating brush to loosen debris(Sony Vaio VGN-FZ31S battery). Unable to produce the design himself due to lack of funding, he sold the patent in 1908 to William Henry Hoover who had Spangler's machine redesigned with a steel casing, casters, and attachments. Subsequent innovations included the first disposal filter bags in the 1920s and the first upright vacuum cleaner in 1926(SONY VAIO VGN-FZ31E Battery).

Hoover

Spangler patented his rotating-brush design June 2, 1908, and eventually sold the idea to his cousin's husband, Hoover. He was looking for a new product to sell, as the leather goods produced by his 'Hoover Harness and Leather Goods' company were becoming obsolete, because of the invention of the automobile(SONY VAIO VGN-FZ31J Battery). In the United States, Hoover remains one of the leading manufacturers of household goods, including vacuum cleaners; and Hoover became very wealthy from the invention. Indeed, in Britain the name Hoover became synonymous with the vacuum cleaner so much so that one "hoovers one's carpets"(SONY VAIO VGN-FZ31M Battery). Initially called 'The Electric Suction Sweeper Company', their first vacuum was the 1908 Model O, which sold for $60.

Constellation

Hoover is also notable for an unusual vacuum cleaner, the Hoover Constellation, which is a cylinder type but lacks wheels. Instead, the vacuum cleaner floats on its exhaust, operating as a hovercraft, although this is not true of the earliest models(SONY VAIO VGN-FZ31B Battery). They had a swivel top hose with the intention being that the user would place the unit in the center of the room, and work around the cleaner. Introduced in 1952, they are collectible, and are easily identified by the spherical shape of the housing. They tended to be loud, had poor cleaning power, and could not float over carpets(HP PAVILION DV6000 battery). But they remain an interesting machine; restored, they work well in homes with lots of hardwood floors.

The Constellations were changed and updated over the years until discontinued in 1975. These Constellations route all of the exhaust under the vacuum using a different airfoil. The updated design is quiet even by modern standards(SONY VGP-BPS13 Battery), particularly on carpet as it muffles the sound. These models float on carpet or bare floor—although on hard flooring, the exhaust air tends to scatter any fluff or debris around.

Hoover has now re-released an updated version of this later model Constellation in the US (model # S3341 in Pearl White and # S3345 in stainless steel) (SONY VGP-BPS13B/B Battery). Changes include a HEPA filtration bag, a 12 amp motor, a suction turbine powered rotating brush floor head, and a redesigned version of the handle, which tended to break. This same model was marketed in the UK under the Maytag brand as the Satellite because of licensing restrictions(ASUS EEE PC battery).

The 5.2 amp motor on older US units provides respectable suction but they all lack a motorized brush head. Therefore they generally work better on hard floors or short pile rugs. Old units take Hoover type J paper bags but the slightly smaller type S allergen filtration bags can be easily trimmed to fit the retaining notches on the old vacuums. Replacement motors are still available from Hoover US for some models(ASUS EEE PC900 battery).

Hoover made another hovering vacuum cleaner model called the Celebrity in 1973. It has a flattened "flying saucer" shape. Hoover added wheels to it make it a conventional cylinder model after a brief run as a hovering vacuum. It uses "Type H" bags(Dell INSPIRON 1525 battery).

Nilfisk

In 1910, P.A. Fisker patented a vacuum cleaner using a name based on the company’s telegram address—Nilfisk. It was the first electric vacuum cleaner in Europe. His design weighed just 17.5 kg and could be operated by a single person. The company Fisker and Nielsen was formed just a few years before. Today the Nilfisk vacuums are delivered by Nilfisk-Advance(Dell INSPIRON E1505 battery).

Electrolux Model V

The first vacuum cleaners were bulky stand-up units and not easily portable. But in 1921 Electrolux launched the Model V, that was designed to lie on the floor on two thin metal runners. This innovation, conceived by Electrolux founder Axel Wenner-Gren, became a standard feature on generations of future vacuum cleaners(Dell INSPIRON 1420 battery).

There is a recorded example of a 1930s Electrolux vacuum cleaner surviving in use for over 70 years, finally breaking in 2008.

Post-World War II

For many years after their introduction, vacuum cleaners remained a luxury item; but after World War II they became common among the middle classes(Dell INSPIRON 1520 battery). They tend to be more common in Western countries because, in most parts of the world, wall-to-wall carpetingis uncommon and homes have tile orhardwood floors, which are easily swept, wiped, or mopped.

Cyclonic vacuums

Vacuum cleaners working on the cyclone principle became popular in the 1990s, although some companies (notably Filter Queen and Regina) (Dell INSPIRON 1464 battery) have been making vacuum cleaners with cyclonic action since 1928. Modern cyclonic cleaners were adapted from industrial cyclonic separators by British designer James Dyson in 1985. He launched his cyclone cleaner first in Japan in the 1980s at a cost of about US$1,800 and later the Dyson DC01 upright in the UK in 1993 for £200(Dell INSPIRON 1564 battery). It was expected that people would not buy a vacuum cleaner at twice the price of a normal cleaner, but it later became the most popular cleaner in the UK. Cleveland's P.A. Geier Company obtained a patent on a cyclonic vacuum cleaner in 1928, which was sold to Health-Mor in 1939 (see http://www.fundinguniverse.com/company-histories/HMI-Industries-Inc-Company-History.html). Filter Queen vacuums use cyclonic action(Dell INSPIRON 1764 battery).

Cyclonic cleaners do not use filtration bags. Instead, the dust is separated in a detachable cylindrical collection vessel or bin. Air and dust are blown at high speed into the collection vessel at a direction tangential to the vessel wall(Dell N3010 Battery), creating a fast-spinning vortex. The dust particles and other debris move to the outside of the vessel bycentrifugal force, where they fall due to gravity. In central or fixed-installation vacuum cleaners, the cleaned air may be exhausted directly outside without need for further filtration(SONY VGP-BPS13/B Battery).

In portable models, the cleaned air from the center of the vortex is expelled from the machine after passing through a number of successively finer filters at the top of the container. The first filter is intended to trap particles which could damage the subsequent filters that remove fine dust particles(Sony VAIO VGN-FZ15T Battery). The filters must regularly be cleaned or replaced to ensure that the machine continues to perform efficiently. Since Dyson, several other companies have introduced cyclone models, including Hoover, Bisell, Eureka, Electrolux, etc. and the cheapest models are no more expensive than a conventional cleaner(Sony VAIO VGN-FZ15G Battery).

Robotic vacuums

In early 2000 several companies developed robotic vacuum cleaners. Some examples are Roomba, Robomaxx, Intellibot, Trilobiteand FloorBot. These machines propel themselves in patterns across a floor, cleaning surface dust and debris into their dustbin. They usually can navigate around furniture and find their recharging stations(SONY VGP-BPS13A/S Battery). Most robotic vacuum cleaners are designed for home use, although there are more capable models for operation in offices, hotels, hospitals, woodshops, etc. Most models are equipped with motorised brushes that sweep debris from the floor into a collection bin. Additionally(SONY VGP-BPS13AS Battery), some such as the Roomba are equipped with an impeller motor to create an actual vacuum, to collect finer dust particles. By the end of 2003 about 570,000 units were sold worldwide.

Other recent developments(SONY VGP-BPS13S Battery)

In 2004 a British company released Airider, a hovering vacuum cleaner that floats on a cushion of air. It has claimed to be light weight and easier to maneuver (compared to using wheels), although it is not the first vacuum cleaner to do this — the Hoover Constellation predated it by at least 35 years(SONY VGP-BPS13B/S Battery).

Technology

A vacuum's suction is caused by a difference in air pressure. An electric fan reduces the pressure inside the machine. Atmospheric pressure then pushes the air through the carpet and into the nozzle, and so the dust is literally pushed into the bag(SONY VAIO PCG-5G2L battery).

Tests have shown that vacuuming can kill 100% of young fleas and 96% of adult fleas.

A British inventor has developed a new cleaning technology known as Air Recycling Technology which instead of using a vacuum uses an air stream to collect dust from the carpet(SONY VAIO PCG-5G3L battery). This technology was tested by the Market Transformation Programme (MTP) and shown to be more energy efficient than the vacuum method. Although working prototypes exist Air Recycling Technology is not currently used in any production cleaner.

Configurations

Vacuum cleaner types include:

Upright

Upright vacuum cleaners are common in the U.S., Britain and several Commonwealth countries, but very unusual in Continental Europe(SONY VAIO PCG-5J1L battery). They take the form of a cleaning head, onto which a handle and bag are attached. Upright designs usually employ a rotating brushroll or beater bar, which removes dirt through a combination of sweeping and vibration. There are two types of upright vacuums; dirty-fan/direct air (found mostly on commercial vacuums), or clean-air/fan-bypass (found on most of today's vacuums) (SONY VAIO PCG-5K2L battery).

The older of the two designs, direct-fan cleaners have a large impeller (fan) mounted close to the suction opening, through which the dirt passes directly, before being blown into a bag. The motor is often cooled by a separate cooling fan(SONY VAIO PCG-5L1L battery). Because of their large-bladed fans, and comparatively short airpaths, direct-fan cleaners create a very efficient airflow from a low amount of power, and make great carpet cleaners. Their 'above-floor' cleaning power is less efficient, since the airflow is lost when it passes through a long hose(SONY VAIO PCG-5J2L battery).

Fan-bypass uprights have their motor mounted after the bag. Dust is removed from the airstream by the bag, and usually a filter, before it passes through the fan. The fans are smaller, and are usually a combination of several moving and stationary turbines working in sequence to boost power(SONY VAIO PCG-6S2L battery). The motor is cooled by the airstream passing through it. Fan-bypass vacuums are good for both carpet and above-floor cleaning, since their suction does not significantly diminish over the distance of a hose, as it does in direct-fan cleaners. However, their air-paths are much less efficient, and can require more than twice as much power than direct-fan cleaners to achieve the same results(SONY VAIO PCG-6S3L battery).

The least common upright vacuum cleaners use a drive-belt powered by the suction motor to rotate the brush-roll. However, a more common design of dual motor upright is available. In these cleaners, the suction is provided via a large motor, while the brushroll is powered by a separate, smaller motor(SONY VAIO PCG-6V1L battery), which does not create any suction. The brush-roll motor can sometimes be switched off, so hard floors can be cleaned without the brush-roll scattering the dirt. It may also have an automatic cut-off feature, which shuts the motor off if the brush-roll becomes jammed, protecting it from damage(SONY VAIO PCG-6W1L battery).

Cylinder

Cylinder models (in the U.S. also often called canister models) dominate the European market. They have the motor and dust collector (using a bag or bagless) in a separate unit, usually mounted on wheels, which is connected to the vacuum head by a flexible hose. Their main advantage is flexibility(SONY VAIO PCG-7111L battery), as you can attach different heads for different tasks, and maneuverability (the head can reach under furniture and makes it very easy to vacuum stairs and vertical surfaces. Many cylinder models have power heads, as standard or add-on equipment, which contain the same sort of mechanical beaters as in upright units(SONY VAIO PCG-6W3L battery), making them as efficient on carpets as upright models. Such beaters are driven by a separate electric motor or a turbine which uses the suction power to spin the brushroll via a drive belt.

Robotic(SONY VAIO PCG-7113L battery)

Robotic vacuum cleaners are a form of carpet sweeper with limited suction power, which move autonomously, usually in a mostly chaotic pattern ("random bounce"). Some come back to a docking station to charge their batteries, and a few are able to empty their dust containers into the dock as well(SONY VAIO PCG-7133L battery).

Hand-held

Hand-held vacuum cleaners, either battery-operated or mains powered, are also popular for cleaning up smaller spills, such as the Black & Decker DustBuster, introduced in 1979, and the various hand-held models from Dirt Devil, first introduced in 1984. Some battery-powered handheld vacuums are wet/dry rated(SONY VAIO PCG-7Z1L battery); the appliance must be partially disassembled and cleaned after picking up wet materials, to avoid developing unpleasant odours.

Drum

Drum models are essentially heavy-duty industrial versions of cylinder vacuum cleaners, where the cylinder consists of a large vertically positioned drum, which can be stationary or on wheels. These models, which can store over 200 litres (53 US gallons), are often hooked up to compressed air and utilize the venturi effect(SONY VAIO PCG-7Z2L battery).

Wet/Dry

Wet or wet/dry or shop vacuum cleaners are a specialized form of the cylinder/drum models that can be used to clean up wet or liquid spills. They commonly can accommodate both wet and dry soilage; some are also equipped with a switch or exhaust port for reversing the airflow, a useful function for everything from clearing a clogged hose to blowing dust into a corner for easy collection(SONY VAIO PCG-8Y1L battery).

Pneumatic

Pneumatic or pneumatic wet/dry vacuum cleaners are a specialized form of wet/dry models that hook up to compressed air. They commonly can accommodate both wet and dry soilage, a useful feature in industrial plants and manufacturing facilities(SONY VAIO PCG-8Y2L battery).

Backpack

Backpack vacuum cleaners are commonly used for commercial cleaning: they allow the user to move rapidly about a large area. They are essentially cylinder vacuum cleaners strapped on the user's back(SONY VAIO PCG-8Z2L battery).

Central

Central vacuum cleaners, also known as built-in or ducted, are a type of cylinder models which have the motor and bag unit located in a central location in the building and provide vacuum inlets throughout the building. Only the hose and head need be carried from room to room, and the hose is commonly 8 m (25 ft) long(SONY VAIO PCG-8Z1L battery), allowing a large range of movement without changing vacuum inlets. Plastic or metal piping connects the inlets to the central unit. The vacuum head may be unpowered, or have beaters operated by an electric motor or by an air-driven turbine(SONY VAIO PCG-7112L battery).

The dirt bag or collection bin in a central vacuum system is usually so large that emptying or changing needs to be done less often, perhaps once per year for an ordinary household. The central unit usually stays in stand-by, and is turned on by a switch on the handle of the hose(SONY VAIO PCG-6W2L battery). Alternately, the unit powers up when the hose is plugged into the wall inlet, when the metal hose connector makes contact with two prongs in the wall inlet and control current is transmitted through low voltage wires to the main unit. A central vacuum typically produces greater suction than common vacuum cleaners, because a larger fan and more powerful motor can be used when they are not required to be portable(SONY VAIO PCG-5K1L battery).

Another benefit of a central vacuum system is that unlike a standard vacuum cleaner, which blows some of the dirt collected back into the room being cleaned (no matter how efficient its filtration), a central vacuum removes all the dirt collected to the central unit(SONY pcga-bp2ea battery). Since this central unit is usually located outside the living area, no dust is recirculated back into the room being cleaned. Also it is possible on most newer models to vent the exhaust entirely outside, even with the unit inside the living quarters(SONY VGP-BPS21A/B Battery).

In addition, because of the remote location of the motor unit, there is much less noise in the room being cleaned than with a standard vacuum cleaner.

Attachments

Most vacuum cleaners are supplied with various specialized attachments, such as tools, brushes and extension wands, which allow them to reach otherwise inaccessible places or to be used for cleaning a variety of surfaces(SONY VGP-BPS21B Battery). The most common of these tools are:

Hard floor brush (for non-upright models)

Carpeted floor brush (for non-upright models)

Dusting brush

Crevice tool

Upholstery tool

Exhaust filtration

Vacuums by their nature cause dust to become airborne, by exhausting air that is not completely filtered. This can cause health problems since the operator ends up inhaling this dust(SONY VGP-BPS21 Battery). There are several methods manufacturers are using to solve this problem. Some methods may be combined together in a single vacuum. Typically the filter is positioned so that the incoming air passes through it before it reaches the motor. Typically, the filtered air then passes through the motor for cooling purposes(SONY VGP-BPS21/S Battery).

Ordinary vacuum cleaners should never be used to clean up asbestos fibres, even those fitted with a HEPA filter.

Bag: The bag is the typical method to capture the debris vacuumed up. It involves a paper or fabric bag that allows air to pass through, but attempts to trap all dust and debris in the bag. The bag may be disposable, or designed to be cleaned and re-used(SONY Vaio PCG-F305 battery).

Bagless: In non-cyclonic bagless models, the role of the bag is taken by the container and a reusable filter, equivalent to a reusable fabric bag.

Cyclonic separation: Vacuum cleaners employing this method are also bagless. It causes intake air to be cycled or spun so fast that the dust is forced out of the air and falls into a storage bin. The operation is similar to that of a centrifuge(SONY VGP-BPS13A/Q Battery).

Water filtration: First seen commercially in the 1920s in the form of the Newcombe Separator (later to become the Rexair Rainbow), water filtration vacuum cleaners use water as a filter. It forces the intake air to pass through water before it is exhausted. The idea behind this is that wet dust cannot become airborne(SONY VGN NR11Z/T battery). They require the dirty water to be dumped and the machine rinsed out after every use, to prevent unpleasant odors and mold growth.

Ultra fine air filter: Also called HEPA filtered. This method is used as a secondary filter after the air has passed thought the rest of the machine. It is meant to remove any remaining dust that could harm the operator. Some vacuum cleaners also use a charcoal filter to remove odors(SONY VGN NR11Z/S battery).

Specifications

The performance of a vacuum cleaner can be measured by several parameters:

airflow, in cubic feet per minute (CFM or ft³/min) or litres per second (l/s)

air speed, in miles per hour (mph) or metres per second (m/s)

suction, vacuum, or water lift, in inches of water or pascals (Pa)

Other specifications of a vacuum cleaner are:

weight, in pounds (lb) or kilograms (kg)

noise, in decibels (dB)

power cord length and hose length (as applicable)

Performance metrics(SONY VGN NR11M/S battery)

Suction

The suction is the maximum pressure difference that the pump can create. For example, a typical domestic model has a suction of about negative 20 kPa. This means that it can lower the pressure inside the hose from normal atmospheric pressure (about 100 kPa) by 20 kPa(SONY VGN NR11S/S battery). The higher the suction rating, the more powerful the cleaner. One inch of water is equivalent to about 249 Pa; hence, the typical suction is 80 inches (2,000 mm) of water.

Input power

The power consumption of a cleaner, in watts, is often the only figure stated. Many North American vacuum manufacturers only give the current in amperes (e.g. "12 amps") and the consumer is left to multiply that by the line voltage of 120 volts to get the approximate power ratings in watts(SONY VGP-BPS13B/Q Battery). The power does not indicate the effectiveness of the cleaner, only how much electricity it consumes.

Output power

The amount of this power that is converted into airflow at the end of the cleaning hose is sometimes stated, and is measured in airwatts: the units are simply watts; "air" is used to clarify that this is output power, not input electrical power(SONY VGP-BPS13Q Battery).

The airwatt is derived from English units. ASTM International defines the airwatt as 0.117354 * F * S, where F is the rate of air flow in ft3/m and S is the pressure in inches of water. This makes one airwatt equal to 0.9983 watts(SONY Vaio VGN-FW21M Battery).