water wheel is a machine for converting the energy of water that flows or falls into useful power form, often in watermill. The water wheel consists of wheels (usually made of wood or metal), with a number of knives or buckets arranged on the outer edge forming the steering wheel. Most commonly, the wheel is mounted vertically on a horizontal axis, but can also be mounted horizontally on a vertical axis, eg tub or Norse. Vertical wheels can transmit power either through the shaft or through the ring gear and usually push the belt or gear; horizontal wheels usually directly push the load.
The water wheel is still used commercially until the 20th century but is no longer in general use. Uses include flour milling in gristmills, grinding wood into pulp for paper making, hammering wrought iron, machining, crushing ore and pounding fibers for use in fabric manufacture.
Some of the water wheels are fed by water from the milling pool, which is formed when the flowing stream is dammed. Channels for water flowing to or from the water wheel are called factory races. The race carrying water from the factory pool to the water wheel is headrace ; carrying water after leaving the wheel is usually referred to as tailrace .
In the mid to late 18th century, John Smeaton's scientific investigation of the water wheel led to a significant increase in the much needed power-supply efficiency for the Industrial Revolution.
The water wheel began to be moved by a smaller, cheaper and more efficient turbine developed by BenoÃÆ'®t Fourneyron, starting with its first model in 1827. Turbines were able to handle high heads, or elevations, practical-sized waterwheel capability.
The main difficulty of the water wheel is their dependence on the flowing water, which limits where they can be found. Modern hydroelectric dams can be seen as a water wheel derivative, as they also utilize a decreased water movement.
Video Water wheel
Jenis
The water wheel has two basic designs:
- horizontal wheel with vertical axis; or
- vertical wheel with horizontal axis.
The latter can be subdivided based on where the water strikes the wheel into the backshot (pitch-back) beyond the borders, chest, undershot, and wheel-current. The term undershot can refer to any wheel that passes under the water under the wheels but it usually implies that the ingress of water in the wheels is low.
Most water wheels in the United Kingdom and United States are (or) vertical wheels that rotate around the horizontal axis, but in the Scottish highlands and parts of the South European plant often have horizontal wheels (with vertical axis).
Type summary
Overshot and wheel water backshots are usually used where different altitude differences are available over several meters. Breasts are more suitable for large streams with a moderate head. Undershot and the flow of wheels using a large current in the head little or no.
Often there are corresponding millponds, reservoirs to store water and hence energy until needed. The larger head holds more potential energy for the same amount of water so the reservoir for overshot and backshot wheels tend to be smaller than for the breast shot wheel.
The oversift water wheel and pitchback are suitable if there is a small flow with a height difference of more than 2 meters, often associated with a small reservoir. The bottom and bottom wheels can be used in streams or high volume streams with large reservoirs.
Vertical axis
Horizontal wheel with vertical axis.
Generally called tub wheel , Norse grinder or Greek factory , horizontal wheels are a primitive and inefficient form of modern turbines. But if it provides the required power then efficiency is of secondary importance. Usually installed inside factory buildings under floor work. The water fountain is directed to the water wheel pedal, causing them to spin. It is a simple system usually without gearing so that the vertical axle of the water wheel becomes the driving shaft of the factory.
The earliest known reference to the wheel of water is about 400 BC, and the horizontal axis of the earliest dates to about 200 BC, so the vertical axis mill pre-dates the horizontal axis of about two centuries.
Stream
The flow wheel is a vertically mounted water wheel that is rotated by water in a striking water field or a knife at the bottom of the wheel. This type of water wheel is the oldest horizontal wheel type. They are also known as free surface wheels because water is not limited by millraces or holes.
Streaming wheels are cheaper and easier to build, and have less environmental impact than other types of wheels. They are not a big change of the river. The disadvantage is their low efficiency, which means that they produce less power and can only be used where the flow rate is sufficient. A typical flat undershot wheel board uses about 20 percent of the energy in the flashy water flow of a wheel as measured by British civil engineer John Smeaton in the 18th century. The more modern wheels have higher efficiency.
The stream wheels get little or no advantage of the head, the difference in the water level.
Streaming wheels mounted on floating platforms are often referred to as ship wheels and factories as mill vessels . The earliest may have been built by the Byzantine General Belisarius during the Roman siege in 537. Later they were sometimes installed immediately downstream of the bridge where the limitation of the bridge dock flow increased the velocity of the current.
Historically they were very inefficient but great progress was made in the eighteenth century.
Undershot wheel
The undershot wheel is a vertical mounted water wheel with a horizontal axle rotated by water from a low weir that crashed into the wheels in the lower quarter. Most energy derived from water movement and relatively little from the head. They are similar in operation and design to drain the wheels.
The undershot term is sometimes used with different but related meanings:
- all wheels where water passes under the steering wheel
- the wheel where the water comes in at the bottom. Wheels
- where the paddle is placed into the flow stream. View streaming above.
This is the oldest vertical water type.
Birth wheels
The word breastshot is used in various ways. Some authors limit the terms to wheels where water enters at about 10 o'clock positions, others at 9, and others for varying heights. In this article it is used for wheels where the water entry is significantly above the bottom and significantly below the top, usually the middle half.
They are characterized by:
- a carefully shaped bucket to minimize turbulence when water comes in.
- the bucket is ventilated with a hole on the side to allow air out when water enters
- apron masonry "fits perfectly with the wheel surface, which helps hold the water in the bucket as they move downwards
Both kinetic (motion) and potential (high and heavy) energies are used.
The small distance between the wheel and the pair requires the breast wheel to have a good garbage rack ('screen' in English English) to prevent debris from jamming between the wheel and apron and potentially causing serious damage.
The breastshot wheels are less efficient than overshot wheels and backshots but they can handle high flow rates and consequently high power. They are preferred for stable high volume flows such as those found on the North East Coast East Coast Path. Breast wheels are the most common type in the United States and are said to have supported the industrial revolution.
Backshot wheel
The backshot wheel (also called pitchback ) is an overshot wheel variation in which water is introduced just before the top of the wheel. In many situations it has the advantage that the bottom of the wheel moves in the same direction as the water in the tail race which makes it more efficient. It also performs better than the overshot wheel under flood conditions when the water level can sink the bottom of the wheel. It will continue to spin until the water in the pits of the wheels rises high enough on the wheels. This makes this technique particularly suitable for streams that experience significant flow variations and reduce the size, complexity and therefore the cost of the tail race.
The rotation direction of the backshot wheel is the same as the breastshot wheel but in other respects it is very similar to the overshot wheel. See below.
Overshot wheel
A vertical mounted water wheel that is rotated by water entering the bucket only passes the top of the wheel that is said to be surpassed. This term is sometimes mistakenly applied to a backshot wheel where the water drops behind the wheel.
The typical overshot wheels have water supplied to the wheels at the top and slightly outside the shaft. Water accumulates in a bucket on the side of the wheel, making it heavier than the other "empty" side. The weights rotate the wheel, and water flows out to the tail as the wheel spins enough to turn the bucket. The overshot design is very efficient, can reach 90%, and does not require fast flow.
Almost all energy is derived from the weight of water that is lowered to the tail, although small donations can be made by the kinetic energy of water entering the wheel. They are suitable for larger heads than other wheel types so they are perfect for hilly country. But even the largest water wheel, the Laxey Wheels on the Isle of Man, uses only ~ 30m head. The world's largest turbine head, Bieudron Hydroelectric Power Station in Switzerland, utilizes ~ 1869m.
Wheels that are too large require a large head compared to other types of wheels which usually means a significant investment in building a head race. Sometimes the last approach from water to wheel is along the flume or penstock, which can be long.
Maps Water wheel
Hybrid
Overshot and backshot
Several overshot wheels at the top and backshots at the bottom thus potentially incorporating the best features of both types. The photo shows an example at Finch Foundry in Devon, England. Head racing is a wooden structure on top and branches to the left supplying water to the wheels. Water comes out from under the wheel back to the river.
Reversible
A special type of overshot/backshot wheel is an invertible water wheel. It has two sets of knives or buckets that run in opposite directions, so it can rotate in both directions depending on which side of the water is directed. The reversible wheel is used in the mining industry to drive various means of transporting ores. By changing the direction of wheels, barrels or baskets of ore can be lifted or lowered down the shaft or incline. Usually there is a drum cable or chain basket (German: Kettenkorb) on the wheel axle. It is important that the wheel has braking equipment to be able to stop the wheel (known as the braking wheel). The oldest reversible water wheel drawing known by Georgius Agricola and dating from 1556.
Suspension wheels and gears
The two initial improvements are the suspension wheels and rim gears. The suspension wheels are built in the same way as bicycle wheels, rims supported under the voltage of the hub - this causes the lighter wheels to be larger than the previous design where the heavy fingers are under compression. Rims of circular gears by adding a curved wheel to the rim or a wheel shroud. A stub gear uses a rim-gear and brings power to the mill using an independent axis line. This removes the rotative voltage from the shaft which may be lighter, and also allows more flexibility at the power train location. The rotation of the shaft is directed from the wheel causing less power loss. An example of this design pioneered by Thomas Hewes and perfected by William Fairburn can be seen on a wheel that was restored in 1849 at the Portland Basin Canal Warehouse.
History
The two main functions of a water wheel have historically been the lifting of water for irrigation purposes and as a source of electricity. When used for lifting weights can be given by human or animal forces or by the flow of water itself.
The water wheel comes in two basic designs, either vertical or horizontal shaft. The latter type can be divided, depending on where the water touches the wheel, into the backshot, overshot, breastshot and undershot wheels.
It is not clear from the historical text and archeology that it is available whether the waterwheel originated in Egypt, India, Greece, or regions in between; use in just a few decades of their respective cultures in the 4th to 3rd centuries B.C.E. documented on a large swath of Eurasia.
Ancient Egyptian
The paddle-driven water-lift wheel had appeared in ancient Egypt in the 4th century BC. The Egyptians are credited with creating a water wheel with an attached pot, a water wheel with a water compartment and a bucket chain, which runs over the pulleys with a bucket attached to it. The discovery of the wheeled water wheel occurred in ancient Egypt around the 4th century BC, in a rural context, away from the metropolis of Hellenistic Alexandria, and then spread to other parts of North Africa.
According to John Peter Oleson, the compartment wheel and the hydraulic Noria appeared in Egypt in the 4th century BC, with Sakia found there a century later. This is supported by archaeological findings in Faiyum, where the oldest archaeological evidence of a water wheel has been found, in the form of Sakia dating from the 3rd century BC. A papyrus dating from the 2nd century BC also found in Faiyum mentions a water wheel used for irrigation, a 2nd century BC fresco found in Alexandria describes Sakia being compiled, and the writings of Callixenus of Rhodes mention the use of Sakia in Ptolemaic Egypt during the reign of Ptolemy IV at the end of the 3rd century BC.
Greco-Roman Mediterranean
The Mediterranean engineers of the Hellenistic and Roman periods used a water wheel for irrigation and as a source of electricity. Its use in the Greco-Roman world dates back to the Hellenistic period technically advanced and scientifically thought between 3 and 1 century BC.
Drainage wheels
The Romans used the wheel of water extensively in mining projects. Some such devices are described by Vitruvius. What was discovered during modern mining at the Copper mine in Rio Tinto in Spain involves 16 wheels piled on top of each other so as to lift water about 80 feet (24 m) from hoarding. Part of the same wheel dated around 90 CE, was discovered in the 1930s, in Dolaucothi, a Roman gold mine in south Wales.
Water mills
Taking indirect evidence into account from the work of Greek technician Apollonius of Perge, the British tech historian M.J.T. Lewis dated the emergence of a vertical-axle water mill to the beginning of the 3rd century BC, and a horizontal-shaft watermill for about 240 BC, with Byzantium and Alexandria as the place of discovery. A water wheel reported by the Greek geographer Strabon (about 64 BC - CE 24) existed before 71 BC at the court of Pontian King Mithradates VI Eupator, but the exact construction can not be obtained from the text (XII, 3). , 30 C 556).
The first clear description of the watermill being driven is from the 1st century BC Roman architect Vitruvius, which tells of the sakia gearing system as applied to the watermill. Vitruvius accounts are very valuable because they show how a waterwheel appears, that is, with a combination of Greek discovery apart from toothed teeth and a water wheel into an effective mechanical system to harness the power of water. The water wheel of Vitruvius is described as drowning with its lower end on the water way so that the oars can be driven by the speed of the flowing water (X, 5.2).
At the same time, the overshot wheel appeared for the first time in a poem by Antipater of Thessalonica, who praised it as a labor-saving tool (IX, 418.4-6). This motif is also taken by Lucretius (about 99-55 BC) which likens the rotation of the water wheel with the movement of the stars on the horizon (V 516). The third horizontal-axle type, the breastshot water wheel, becomes archaeological evidence by the context of the 2nd century AD in the center of Gaul. Most of the excavated Roman watermills are equipped with one wheel which, although more complex to build, is much more efficient than a vertical axle water wheel. In the 2nd century AD, the Barbignon waterwheel complex of a series of sixteen oversie wheels was fed by artificial water channels, a proto-industrial grain mill that has been referred to as "the greatest concentration of mechanical forces in the ancient world".
In the Roman North Africa, several installations of about 300 AD were found where a vertical-shaft water wheel was fitted with a sloping knife mounted at the bottom of the shaft, full of circular water. The water from the refinery race that enters the hole tangentially creates a rotating water column that keeps the fully submerged wheel acting like a true water turbine, the earliest known to date.
Regardless of its use in milling and lifting, ancient engineers applied a water wheel pedaled for automatics and navigation. Vitruvius (X 9.5-7) describes a multi-wheeled row wheel that acts as a ship's odometer, the earliest of its kind. The first mention of the rowing wheel as a driving force comes from the fourth and fifth-century military treatises De Rebus Bellicis (chapter XVII), in which the anonymous Roman author describes a cattle-driven oarsman.
China
The Chinese water wheel almost certainly has a separate origin, because the starting wheels always have horizontal water wheels. At least in the 1st century AD, the Chinese from the Eastern Han Dynasty used a water wheel to destroy the grain in the factory and to light the pistons in forging iron ore into cast iron.
In a text known as Xin Lun written by Huan Tan around 20 AD (during Wang Mang's seizure), it states that the legendary mythological king known as Fu Xi is the person responsible for the pestle and mortar, which evolved into a tilt-hammer hammer device and then trip (see trip hammer). Although the author speaks of Fu Xi mythology, a passage from his writings provides clues that the water wheel has been used extensively by the 1st century in China (Wade-Giles spelling):
Fu Hsi found alu and mortar, which was very useful, and then cleverly repaired in such a way that the entire weight could be used to step on the tilt-hammer ( tui ), thereby increasing the efficiency of ten times. After that animal powers - donkeys, mules, cattle, and horses - were applied to machines, and water power was also used to strike, so the benefits increased a hundredfold.
In 31 CE, engineers and prefects of Nanyang, Du Shi (d.38), applied the use of elaborate water wheels and machines to light bellows blast furnaces to make cast iron. Du Shi is mentioned briefly at Book of Later Han ( Hou Han Shu ) as follows (in Wade-Giles spelling):
In the seventh year of the reign of Chien-Wu (31 AD) Tu Shih was placed to become the Nanyang Prefect. He is a generous man and his policy is peaceful; he destroys the culprits and builds dignity (in his office). Good in planning, he loves ordinary people and hopes to save their workforce. He created a water power reciprocator ( shui phai ) for casting (iron) farming tools. Those who melt and throw away already have push-bellows to blow up their charcoal fire, and now they are ordered to use the flowing water ( chi shui ) to operate it... Thus the people benefit greatly less labor. They found 'water (-powered)' which is comfortable and widely adopted.
The water wheel in China finds practical uses of this kind, as well as tremendous usage. The Chinese inventor, Zhang Heng (78-139) was the first in history to apply the motive force in turning the armilaris ball astronomical instruments, using a water wheel. Mechanical engineer Ma Jun (about 200-265) from Cao Wei once used a water wheel to turn on and operate a large mechanical doll theater for Emperor Ming Wei ( r. 226-239).
India
The earliest history of waterwheels in India is unclear. The Indian manuscripts dating from the 4th century BC refer to the term cakkavattaka (rotating wheel), described by the commentary as directionatta-ghati-yanta (engine with wheels attached). On this basis, Joseph Needham suggested that the machine was noria. Terry S. Reynolds, however, argues that "the terms used in the Indian text are ambiguous and do not clearly indicate a water-powered device". Thorkild SchiÃÆ'¸ler argues that it is "more likely that these parts refer to some type of tread or hand operated treadmill, rather than water-powered wheel lifts".
According to the Greek historical tradition, India received a water milling from the Roman Empire in the early 4th century AD when certain Metrodoros introduced "water mills and baths, unknown among them [Brahmins] up to that time". Irrigation water for plants is provided by using a water lifter wheel, some driven by the force of the current in the river from which it was raised. This type of water-lifting device was used in ancient India, which preceded, according to Pacey, its use in the later Roman or Chinese Empire, although the first literary, archaeological and drawing evidence of a water wheel emerged in the Hellenistic world.
Around the year 1150, Bhaskara Achyya astronomers observed the wheels that lifted the water and imagined such a wheel lifting enough water to fill the flow that moved it, effectively, a perpetual motion machine. The construction of water works and water technology aspects in India is described in Arabic and Persian works. During the middle ages, the diffusion of irrigation technologies of India and Persia brought forward an advanced irrigation system that brought economic growth and also helped the growth of material culture.
Islamic World
The Arab engineers took over the water technology of the hydraulic society in the ancient Near East; they adopted the Greek water wheel as early as the seventh century, the excavation of the Basra basin discovered the remains of the water wheel from this period. Pests in Syria still retain some of the big wheels, on the Orontes river, although they are no longer in use. One of the largest has a diameter of about 20 meters and the rim is divided into 120 compartments. The other wheels that are still operating are found in Murcia in Spain, La Nora, and although the original wheels have been replaced with steel ones, the Moorish system over al-Andalus is virtually unchanged. Some of the medieval Islamic compartmented water wheel can lift water as high as 30 meters. Muhammad ibn Zakariya al-Razi Kitab al-Hawi in the 10th century depicts a noria in Iraq that can lift as many as 153,000 liters per hour, or 2550 liters per minute. This is comparable to modern norias output in East Asia, which can lift up to 288,000 liters per hour, or 4800 liters per minute.
The use of the watermills industry in the Islamic world dates back to the 7th century, while horizontal water wheels and vertical wheels were both widely used by the 9th century. Various industrial water mills are used in the Islamic world, including gristmill, huller, sawmills, shipmills, stamp mills, steel mills, sugar mills, and tidal mills. In the 11th century, every province throughout the Islamic world has these industrial water mills operating, from al-Andalus and North Africa to the Middle East and Central Asia. Muslim and Christian engineers also use crankshafts and water turbines, gears in watermills and water-treatment machines, and dams as a water source, which is used to provide additional power for watermills and water-raising machines. Mill mills and full steel plants may have spread from Spanish to Spanish Spain in the 12th century Spain. Industrial water mills are also used in large factory complexes built in al-Andalus between the 11th and 13th centuries.
Engineers from the Islamic world developed several solutions to achieve maximum output from the water wheel. One solution is to install it to the bridge dock to take advantage of the increased flow. Another solution is the shipmill, a type of water mill driven by a water wheel mounted on the side of the ship which is moored in the middle of the current. This technique is used along the Tigris and Euphrates rivers in 10th century Iraq, where large ships made of teak and iron can produce 10 tons of corn flour each day for barns in Baghdad. The flywheel mechanism, used to smooth the transmission of force from the driving device to the driven machine, was created by Ibn Bassal (Fl.1038-1075) from Al-Andalus; he pioneered the use of flywheel in saqiya (chain pumps) and noria. Al-Jazari engineers in the 13th century and Taqiuddin in the 16th century described many inventive water-raising machines in their technology treatises. They also use a water wheel to power various devices, including various water clocks and automata.
Medieval Europe
Ancient water wheel technology continued in the early Middle Ages where the emergence of new documentary genres such as legal codes, monastic charters, but also hagiography accompanied by a sharp increase of references to watermills and wheels.
The earliest vertical wheel in a tidal plant is from a 6th-century Killoteran near Waterford, Ireland, while the first horizontal wheel known in that kind of milling originated from the Small Island of Ireland (about 630). As for the use in the Norse or Greek plant, the oldest horizontal wheel known to be unearthed in Irish Ballykilleen, dating c. 636.
The earliest tidal excavation wheel driven by tidal power is the Nendrum Monastery factory in Northern Ireland that has been dated to 787, although it may be the date of its initial milling up to 619. Tidal mills are common at estuaries with a good tidal range in Europe and America generally. use undershot wheel.
Cistercian monasteries, in particular, use many water wheels to move different types of water. The earliest example of a very large water wheel is the wheel that still existed at the beginning of the 13th century Real Monasterio de Nuestra Senora de Rueda, the Cistercian monastery in the Aragon region of Spain. The milling mill (for corn) is undoubtedly the most common, but there are also saw mills, factories and full factories to fulfill many other labor-intensive tasks. The water wheel remains competitive with steam engines until the Industrial Revolution. In the 8th to 10th centuries, a number of irrigation technologies were brought to Spain and later introduced to Europe. One such technology is Noria, which is basically a wheel fitted with a bucket on peripherals to lift water. This is similar to the undershot water wheel mentioned later in this article. This allows farmers to move the waterwheel more efficiently. According to Thomas Glick's book, Irrigation and Society in the Middle Ages of Valencia , Noria probably came from somewhere in Persia. It has been used for centuries before technology was brought to Spain by the Arabs who had adopted it from the Romans. Thus the distribution of Noria on the Iberian peninsula "corresponds to a stable area of ​​Islamic settlement". This technology has a profound effect on the life of farmers. Noria is relatively cheap to build. Thus it allows farmers to cultivate land more efficiently in Europe. Along with the Spaniards, technology spread to the New World in Mexico and South America after the Spanish expansion.
Inventory of British factory expiration c. 1086
The trial hosted by William of Normandy, usually referred to as the "Domesday" or Doomsday survey, took inventory of all the UK's taxable properties, which included more than six thousand factories spread across three thousand different locations.
Locations
The type of water wheel selected depends on the location. Generally if only small volumes of water and high waterfall are available, millwright will choose to use overshot wheels. The decision was influenced by the fact that the bucket could catch and use even small amounts of water. For large volumes of water with a small waterfall, undershot wheels will be used, as more adapted to such conditions and less expensive to build. As long as the water supply is abundant, efficiency questions remain irrelevant. In the 18th century with increasing demand for power combined with limited water areas, emphasis was made on the efficiency scheme.
Economic influence
In the 11th century there were parts of Europe where water exploitation was commonplace. The water wheel is understood to have been actively shaped and forever changed the Western view. Europe began to transit from human and animal muscle workers to mechanical work with the advent of water wheels. Medievalist Lynn White Jr. argues that the inanimate resource deployment is an impressive testimony to the emergence of the West from a new attitude toward, power, work, nature, and above all technology.
Harnessing the power of water allows gains in agricultural productivity, food surplus and large-scale urbanization beginning in the 11th century. The usefulness of water forces motivates European experiments with other resources, such as wind and tidal plants. Waterwheels affect the construction of the city, more specifically the canal. Techniques developed during this early period such as flow jamming and channel construction, put Europe on hydraulically focused paths, such as water supply and irrigation technologies combined to change the wheel's supply strength. Describes the extent to which there are many technological innovations that meet the needs of a feudal state that continues to grow.
Water wheel app
The water mill is used to grind grains, produce flour for bread, malt for beer, or coarse food for porridge. Hammermills uses wheels to operate the hammer. One of its kind is fulling mill, which is used to make cloth. The travel hammer is also used to make wrought iron and to work iron into a useful form, an activity that should be labor intensive. Water wheels are also used in making paper, battering material to the pulp. In a 13th century water mill used to hammer the rest of Europe to improve the productivity of early steel manufacturing. Along with the mastery of gunpowder, hydro power gave European countries world-wide military leadership from the 15th century.
Europe 17th and 18th in Europe
Millwrights distinguish between two forces, impulses and weight, working on the water wheel long before the 18th century in Europe. Fitzherbert, a 16th-century agricultural writer, writes "cutting the wheel and also with the weight of water as with the force of [impulse]". Leonardo da Vinci also discussed the power of water, noting "the water [punch] is not heavy, but exciting the heavy force, almost the same as his own strength". However, even the realization of two forces, weight and drive, the confusion remains above the advantages and disadvantages of both, and there is no clear understanding of superior weight efficiency. Prior to 1750, it was not certain which dominant and widely understood power that both forces operate with the same inspiration between each other. Waterwheel, sparking questions about the laws of nature, especially the law of force. Evangelista Torricelli's work on the water wheel uses Galileo's analysis of the fall of the body, that the speed of water coming out of the hole beneath his head is exactly the same as the speed of a drop of water obtained by free fall from the same height.
European Industry
The most powerful water wheel built in England is the Quarry Bank Mill 100Ã, water wheel near Manchester. The high breastshot design, it retired in 1904 and replaced with several turbines. It has now been restored and is a museum open to the public.
The largest working water wheel on the British mainland has a diameter of 15.4 m and was built by the De Winton company of Caernarfon. Located within the Dinorwic National Slate Museum workshop in Llanberis, North Wales.
The largest working water wheel in the world is the Laxey Wheels (also known as Lady Isabella) in the village of Laxey, Isle of Man. It is 72Ã, foot 6Ã, inch (22.10 m) in diameter and 6 feet (1.83 m) wide and is managed by Manx National Heritage.
The development of water turbines during the Industrial Revolution caused a decrease in the popularity of water wheels. The main advantage of the turbine is its ability to utilize the head much larger than the diameter of the turbine, while the water wheel can not effectively utilize the head larger than its diameter. The migration of the water wheel to a modern turbine takes about a hundred years.
Modern developments
Hydraulic wheel
The latest development on the breastshot wheel is a hydraulic wheel that effectively incorporates automatic regulatory system. The Aqualienne is one example. It produces between 37 kW and 200 kW of electricity from a water flow of 20mÃ, with heads of 1 to 3.5 m. It is designed to generate electricity at the site of former watermills.
Efficiency
The Overshot wheel (and especially the backshot) is the most efficient type; steel backshot wheels can be more efficient (about 60%) than all but the most sophisticated and well-built turbines. In some situations, overshot wheels are preferred over turbines.
Development of hydraulic turbine wheels with increased efficiency (67%) opens alternative paths for installation of water wheels at existing plants, or rebuilding of abandoned factories.
Wheel strength
The available energy for the wheel has two components:
- Kinetic energy - depends on how fast the water moves when it enters the wheel
- Potential energy - depending on changes in water level between in and out of the wheel
Kinetic energy can be accounted for by turning it into an equivalent head, head speed, and adding it to the actual head. For silent water, the head speed is zero, and for a good approach it can be neglected to slowly move, and be negligible. The speed in the tail race is not taken into account because for the perfect wheel the water will leave with zero energy requiring zero speed. That is impossible, water must move away from the wheel, and is the cause of inevitable inefficiency.
dotted notation
Measurement
Tekanan kepala adalah perbedaan ketinggian antara kepala dan permukaan air balap ekor.
Kepala Keith dihitung dari kecepatan air dalam perlombaan kepala di tempat yang sama dengan tekanan kepala diukur dari.
Speed ​​(speed) can be measured by the pooh sticks method, setting the object time to float above the measured distance. Water on the surface moves faster than water closer to the bottom and sides so that the correction factor should be applied as in the formula below.
There are many ways to measure the volume flow rate. The two simplest are:
- From the cross-sectional area and the speed. They should be measured in the same place but it could be anywhere in the head or tail races. It must have the same amount of water through it as a wheel.
- It is sometimes practical to measure the volume flow rate by bucket and stop watch methods.
Formula
The rule of thumb
Breasts and overshot
Traditional undershot wheel
Wheel turbine hydraulic reaction part
The parallel development is a wheel turbine/hydraulic reaction section which also incorporates a weir to the center of the wheel but uses a knife that is tilted to the water stream. The WICON-Stem Pressure Machine (SPM) exploits this flow. Estimated efficiency of 67%.
The Faculty of Civil and Environmental Engineering of the University of Southampton in England has investigated both types of hydraulic wheel machines and has estimated the hydraulic efficiency and recommended improvements, the Rotary Hydraulic Pressure Machine. (Estimated maximum efficiency of 85%).
This type of water wheel has high efficiency at variable load/current section and can operate on very low head, & lt; 1 meter. Combined with Direct Axial Flux Permanent Magnet Alternators and power electronics, they offer a viable alternative to low head hydroelectric power.
Water-lifting
In a water drive device, rotary motion is usually more efficient than a machine based on oscillatory motion.
The compartmented water wheels come in two basic shapes, wheels with compartmented body (Latin tympanum ) and wheels with compartative rims or rims with separate and attached containers. The wheels can be reversed by the flow of water, people stepping outside it or with animals through the sakia tool. While the tympanum has a large discharge capacity, it can lift water only to less than its own radius height and requires large torque to spin. This constructive deficiency is overcome by the wheel with a compartment rim which is a less heavy design with higher lift.
- Ptolemaic Egypt
The earliest literary reference for water-driven compartmented wheels appears in the technical treatise of Pneumatica (ch. 61) of the Greek engineer Philo of Byzantium (ca. 280-220 BC). In his book Parasceuastica (91.43-44), Philo suggests the use of such wheels to soak the siege mine as a defensive measure against a weakened enemy. The compartment wheel appears to be the preferred means of draining a dry dock in Alexandria under the reign of Ptolemy IV (221-205 BC). Some Greek papyri from the 3rd century to the 2nd century BC mention the use of these wheels, but do not provide any further details. The absence of devices in the Ancient Near East prior to Alexander's conquest can be inferred from the pronounced absence of rich oriental iconography on irrigation practices. Unlike other water-lifting devices and pumps during that period, the discovery of the wheel of the compartment could not be traced to certain Hellenistic engineers and may have been made in the late 4th century BC in the remote rural context of the metropolis of Alexandria.
The earliest depictions of compiled wheels are from grave paintings in Ptolemaic Egypt dating from the 2nd century BC. It shows a pair of cows paired driving the wheels through sakia teeth, which here for the first time proved too. The Greek tooth sakia system has been shown to be fully developed to the point that "modern Egyptian devices are almost identical". It is assumed that scientists from the Museum of Alexandria, at the time of Greece's most active research center, may have been involved in the invention. An episode of the Wars of Alexandria in 48 BC tells of how Caesar's enemies used moving water wheels to pour seawater from high places in the position of trapped Romans.
Around 300 AD, noria was finally introduced when the wood compartment was replaced with a cheap ceramic pot tied to the outside of the open-framed wheel.
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Source of the article : Wikipedia
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