A bellows or pair of bellows is a device constructed to furnish a strong blast of air. The simplest type consists of a flexible bag comprising a pair of rigid boards with handles joined by flexible leather sides enclosing an approximately airtight cavity which can be expanded and contracted by operating the handles, and fitted with a

valve A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fitting ...

allowing air to fill the cavity when expanded, and with a tube through which the air is forced out in a stream when the cavity is compressed. xford English Dictionary, 2nd ed: bellows/ref> It has many applications, in particular blowing on a fire to supply it with air. English Bellows

The term "bellows" is used by extension for a flexible bag whose volume can be changed by compression or expansion, but not used to deliver air. For example, the light-tight (but not airtight) bag allowing the distance between the

lens A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements'' ...

and film of a folding photographic camera to be varied is called a bellows.

Etymology

Remscheid - Deutsches Werkzeugmuseum 06 ies

"Bellows" is only used in plural. The Old English name for "bellows" was , 'blast-bag', 'blowing-bag'; the prefix was dropped and by the eleventh century the simple , , ('bag') was used. The word is

cognate In historical linguistics, cognates or lexical cognates are sets of words in different languages that have been inherited in direct descent from an etymological ancestor in a common parent language. Because language change can have radical e ...

with " belly". There are similar words in

Old Norse Old Norse, Old Nordic, or Old Scandinavian, is a stage of development of North Germanic languages, North Germanic dialects before their final divergence into separate Nordic languages. Old Norse was spoken by inhabitants of Scandinavia and t ...

, Swedish, and Danish and Dutch (blaasbalg), but the derivation is not certain. 'Bellows' appears not to be cognate with the apparently similar Latin .

Metallurgy

Several processes, such as metallurgical iron

smelting Smelting is a process of applying heat to ore, to extract a base metal. It is a form of extractive metallurgy. It is used to extract many metals from their ores, including silver, iron, copper, and other base metals. Smelting uses heat and a ...

and

welding Welding is a fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing fusion. Welding is distinct from lower temperature techniques such as br ...

, require so much heat that they could only be developed after the invention, in

antiquity Antiquity or Antiquities may refer to: Historical objects or periods Artifacts *Antiquities, objects or artifacts surviving from ancient cultures Eras Any period before the European Middle Ages (5th to 15th centuries) but still within the histo ...

, of the bellows. The bellows are used to deliver additional air to the fuel, raising the rate of combustion and therefore the heat output. Various kinds of bellows are used in

metallurgy Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys. Metallurgy encompasses both the sci ...

: * Box bellows were and are traditionally used in East Asia. * Pot bellows were used in ancient Egypt. * Tatara foot bellows from Japan. * Accordion bellows, with the characteristic pleated sides, have been used in Europe for many centuries. * Piston bellows developed in Southeast Asia (probably by the

Austronesian peoples The Austronesian peoples, sometimes referred to as Austronesian-speaking peoples, are a large group of peoples in Taiwan, Maritime Southeast Asia, Micronesia, coastal New Guinea, Island Melanesia, Polynesia, and Madagascar that speak Au ...

) using the principles of the similarly indigenous fire piston. It led to the independent development of bronze and

iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in ...

metallurgy in

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

. They were present in various Southeast Asian cultures, and the technology was transported to

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

via the

Austronesian expansion The Austronesian peoples, sometimes referred to as Austronesian-speaking peoples, are a large group of peoples in Taiwan, Maritime Southeast Asia, Micronesia, coastal New Guinea, Island Melanesia, Polynesia, and Madagascar that speak Austro ...

. :*The technology was later adopted and refined by the Han Chinese into the double-action piston bellows, replacing the native Chinese ox hide pot or drum bellows completely. :* Piston bellows were independently developed in the middle of the 18th century in Europe. * Metal bellows were made to absorb axial movement in a dynamic condition. Often referred to as Axial Dynamics bellows types. Chinese bellows were originally made of ox hide with two pots as described in

Mozi Mozi (; ; Latinized as Micius ; – ), original name Mo Di (), was a Chinese philosopher who founded the school of Mohism during the Hundred Schools of Thought period (the early portion of the Warring States period, –221 BCE). The an ...

's book on military technology in the

Warring States Period The Warring States period () was an era in ancient Chinese history characterized by warfare, as well as bureaucratic and military reforms and consolidation. It followed the Spring and Autumn period and concluded with the Qin wars of conquest ...

(4th century BC). By the

Han Dynasty The Han dynasty (, ; ) was an Dynasties in Chinese history, imperial dynasty of China (202 BC – 9 AD, 25–220 AD), established by Emperor Gaozu of Han, Liu Bang (Emperor Gao) and ruled by the House of Liu. The dynasty was preceded by th ...

, contact with Southeast Asian cultures exposed the Chinese to the bamboo-based piston bellows of Southeast Asians. The acquired piston bellows technology completely replaced the Chinese ox hide bellows that by the

Song Dynasty The Song dynasty (; ; 960–1279) was an imperial dynasty of China that began in 960 and lasted until 1279. The dynasty was founded by Emperor Taizu of Song following his usurpation of the throne of the Later Zhou. The Song conquered the res ...

, the ox hide bellows were completely extinct. The

Chinese mechanical engineer Du Shi (d. 38) is credited with being the first to use hydraulic power on a double-action piston pumps, through a waterwheel, to operate bellows in metallurgy. His invention was used to operate piston bellows of blast furnaces in order to forge

cast iron Cast iron is a class of iron– carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impu ...

.Needham, Joseph (1986). ''Science and Civilization in China: Volume 4, Part 2''. Taipei: Caves Books, Ltd., p. 370. The

ancient Greeks Ancient Greece ( el, Ἑλλάς, Hellás) was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity ( AD 600), that comprised a loose collection of cult ...

ancient Romans In modern historiography, ancient Rome refers to Roman civilisation from the founding of the city of Rome in the 8th century BC to the collapse of the Western Roman Empire in the 5th century AD. It encompasses the Roman Kingdom (753–509 B ...

, and other civilizations used bellows in

bloomery A bloomery is a type of metallurgical furnace once used widely for smelting iron from its oxides. The bloomery was the earliest form of smelter capable of smelting iron. Bloomeries produce a porous mass of iron and slag called a ''bloom'' ...

furnaces producing

wrought iron Wrought iron is an iron alloy with a very low carbon content (less than 0.08%) in contrast to that of cast iron (2.1% to 4%). It is a semi-fused mass of iron with fibrous slag inclusions (up to 2% by weight), which give it a wood-like "grain" ...

. Bellows are also used to send pressurized air in a controlled manner in a fired heater. In modern industry, reciprocating bellows are usually replaced with motorized blowers.

Double-acting piston bellows

Double-acting piston bellows are a type of bellows used by

blacksmith A blacksmith is a metalsmith who creates objects primarily from wrought iron or steel, but sometimes from #Other metals, other metals, by forging the metal, using tools to hammer, bend, and cut (cf. tinsmith). Blacksmiths produce objects such ...

s and smelters to increase the air flow going into the forge, with the property that air is blown out on both strokes of the handle (in contrast to simpler and more common bellows that blow air when the stroke is in one direction and refill the bellows in the other direction). These bellows blow a more constant, and thus stronger, blast than simple bellows.Craddock, Paul T. ''Early Metal Mining and Production''. pp. 183-4. Such bellows existed in China at least since the 5th century BC, when it was invented, and had reached Europe by the 16th century.Temple, Robert K.G. (2007). ''The Genius of China: 3,000 Years of Science, Discovery, and Invention'' (3rd edition). London: André Deutsch, pp. 46-49. . In 240 BC, The ancient Greek inventor Ctesibius of Alexandria independently invented a double-action piston bellow used to lift water from one level to another. A piston is enclosed in a rectangular box with a handle coming out one side. The

piston A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas- ...

edges are covered with feathers, fur, or soft paper to ensure that it is airtight and lubricated. As the piston is pulled, air enters from the far side and the air in the near chamber is compressed and forced into a side chamber, where it flows through the nozzle. Then as it is pushed air enters from the near side and the air in the far chamber flows through the same nozzle.

Double-lung accordion bellows

These have three leaves. The middle leaf is fixed in place. The bottom leaf is moved up and down. The top leaf can move freely and has a weight on it. The bottom and the middle leaves contain valves, the top one does not. Only the top lung is connected to the spout. When the bottom leaf is moved up, air is pumped from the bottom lung into the top lung. At the same time air is leaving the bellows from the top lung through the spout, but at a slower rate. This inflates the top lung. Next the bottom leaf is moved down to pull fresh air into the bellows. While this happens the weight on the top leaf pushes it down, so air keeps leaving through the spout. This design does not increase the amount of air flow going into the forge, but provides a more constant air flow compared to a simple bellows. It also provides more even air flow than two simple bellows pumped alternately or one double-acting piston bellows.

Primitive bellows

The pot bellows in the western room, Area A, looking west

In archaeological ruins of the

Levant The Levant () is an approximation, approximate historical geography, historical geographical term referring to a large area in the Eastern Mediterranean region of Western Asia. In its narrowest sense, which is in use today in archaeology an ...

, archaeologists have found primitive pot bellows, consisting of a ceramic pot to which a loose leather hide had been attached at the top. Such pot bellows were constructed with a wide rim, so that the hide covering would transmit a maximum amount of air when pumped. The covering was fastened to the pot with a cord under an out-turned rim, or in a groove just below the rim exterior. An opening near the base served to insert a pipe of pen shapable material whose purpose was to direct the air blast to either the furnace or crucible, and which was usually done through the mediation of a tuyère. Tuyères used in conjunction with pot bellows had the function of protecting the ends of perishable tubes leading from the pot into the fire. Places in Saharan Africa still make use of primitive pot bellows.

Further applications

Fluid transfer applications

*Bellows are used extensively in hydraulic power circuits and cooling loops. *They are an essential part of anesthesia machines. *

Cuckoo clock A cuckoo clock is, typically, a pendulum clock that strikes the hours with a sound like a common cuckoo call and has an automated cuckoo bird that moves with each note. Some move their wings and open and close their beaks while leaning forward ...

s use bellows to blow air through their gedackt (pipes) and imitate the call of the Common Cuckoo bird. *

Musical instrument A musical instrument is a device created or adapted to make musical sounds. In principle, any object that produces sound can be considered a musical instrument—it is through purpose that the object becomes a musical instrument. A person who pl ...

s may employ bellows as a substitute or regulator for air pressure provided by the human lungs: ** Accordion, concertina and related instruments ** Reed organ **

Pipe organ The pipe organ is a musical instrument that produces sound by driving pressurized air (called ''wind'') through the organ pipes selected from a keyboard. Because each pipe produces a single pitch, the pipes are provided in sets called ''rank ...

** Musette de cour, Uilleann Pipes and some other varieties of

bagpipes Bagpipes are a woodwind instrument using enclosed reeds fed from a constant reservoir of air in the form of a bag. The Great Highland bagpipes are well known, but people have played bagpipes for centuries throughout large parts of Europe, ...

** Harmonium and melodeon ** Portative

Expansion joint applications

The term "bellows" is used by extension for a number of applications that do not involve air transfer. *Bellows are widely used in industrial and mechanical applications such as rod boots, machinery way covers, lift covers and rail covers to protect rods, bearings and seals from dirt. *Bellows are widely used on

articulated buses An articulated bus, also referred to as a banana bus, bendy bus, tandem bus, vestibule bus, wiggle wagon, stretch bus, or an accordion bus, (either a motor bus or trolleybus) is an articulated vehicle used in public transportation. It is ...

and

trams A tram (called a streetcar or trolley in North America) is a rail vehicle that travels on tramway tracks on public urban streets; some include segments on segregated right-of-way. The tramlines or networks operated as public transport are ...

, to cover the joint where the vehicle bends. *Bellows are used in mechanical aneroids by acting as a precision indicator of pressure levels based on their lateral movement. *Bellows tubing, a type of lightweight, flexible, extensible tubing may be used for delivery of gas or air at near-ambient pressure, as in early

aqua-lung Aqua-Lung was the first open-circuit, self-contained underwater breathing apparatus (or "scuba") to achieve worldwide popularity and commercial success. This class of equipment is now commonly referred to as a twin-hose diving regulator, or dem ...

designs. * Folding and

view camera A view camera is a large-format camera in which the lens forms an inverted image on a ground-glass screen directly at the film plane. The image is viewed and then the glass screen is replaced with the film, and thus the film is exposed to exa ...

s use bellows to exclude light while allowing the lens to be moved relative to the film plane for focusing and, mainly in view cameras, to allow the lens to slide and tilt to control the image ( camera movements). *Piping expansion joint: In this application, bellows are formed in series to absorb thermal movement and vibration in piping systems that transport high temperature media such as exhaust gases or steam.

Beekeeping

Bee smokers have bellows attached to the side to provide air to a slow burning fuel. This allows for an increased rate of combustion and a temporarily higher output of smoke on command, something desirable when calming domesticated bees.

Gallery

File:Sealed urethane bellows.JPG, Urethane bellows Image:Blowing_Smoke.jpg, A large bellows creates a mushroom cloud at the Exploratorium in

San Francisco, California San Francisco (; Spanish for "Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the fourth most populous in California and 17th ...

References

Notes

Bibliography

*https://web.archive.org/web/20070919010534/http://www.archaeogate.org/egittologia/article/182/8/mersa-gawasis-red-sea-egypt-unoisiao-and-bu-2003-2004-f.html . *Gernet, Jacques, trans. by J. R. Foster (1972): A History of Chinese Civilization, Cambridge University Press.

External links

* *Moyse - Richard J. and Clarence L. Patent-"Method of Making Bellows"- Jan. 1980 - US4325769-
http://www.google.com/patents/US432576
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