St Giles Shopping Centre is a shopping center located in Elgin , Scotland.
91-567: The Centre has two floors and has a glass lift . The Centre is supported with an adjacent car park. It also contains Elgin's bus station . Plans were shown off to the public in July 1987. The shopping centre was developed by Sheraton Caltrust and reused the facade of existing buildings. In April 1990, the developers stated that they predicted the Centre would be completed in September. However, it
182-587: A "Chart for determining the number and size of elevators required for office buildings of a given total occupied floor area". In 1920, Howard B. Cook presented a paper titled "Passenger Elevator Service". This paper marked the first time a member of the elevator industry offered a mathematical means of determining elevator service. His formula determined the round trip time (RTT) by finding the single trip time, doubling it, and adding 10 seconds. In 1923, Bassett Jones published an article titled "The Probable Number of Stops Made by an Elevator". He based his equations on
273-418: A Scottish building or structure is a stub . You can help Misplaced Pages by expanding it . Elevator An elevator ( American English ) or lift ( Commonwealth English ) is a machine that vertically transports people or freight between levels. They are typically powered by electric motors that drive traction cables and counterweight systems such as a hoist , although some pump hydraulic fluid to raise
364-541: A building is at its most busy first thing in the morning; however, in more complicated elevator systems, this model does not work. In 1990, Peters published a paper titled "Lift Traffic Analysis: Formulae for the General Case" in which he developed a new formula which would account for mixed traffic patterns as well as accounting for passenger bunching using Poisson approximation. This new General Analysis equation enabled much more complex systems to be analyzed however
455-497: A closed space (e.g., combustion chamber , firebox , furnace). In the case of model or toy steam engines and a few full scale cases, the heat source can be an electric heating element . Boilers are pressure vessels that contain water to be boiled, and features that transfer the heat to the water as effectively as possible. The two most common types are: Fire-tube boilers were the main type used for early high-pressure steam (typical steam locomotive practice), but they were to
546-423: A common four-way rotary valve connected directly to a steam boiler. The next major step occurred when James Watt developed (1763–1775) an improved version of Newcomen's engine, with a separate condenser . Boulton and Watt 's early engines used half as much coal as John Smeaton 's improved version of Newcomen's. Newcomen's and Watt's early engines were "atmospheric". They were powered by air pressure pushing
637-451: A cylindrical piston like a jack . Elevators are used in agriculture and manufacturing to lift materials. There are various types, like chain and bucket elevators , grain augers , and hay elevators . Modern buildings often have elevators to ensure accessibility, especially where ramps aren't feasible. High-speed elevators are common in skyscrapers . Some elevators can even move horizontally. The earliest known reference to an elevator
728-426: A deeply grooved pulley , commonly called a sheave in the industry. The weight of the car is balanced by a counterweight . Oftentimes two elevators (or sometimes three) are built so that their cars always move synchronously in opposite directions, and are each other's counterweight. The friction between the ropes and the pulley furnishes the traction which gives this type of elevator its name. Hydraulic elevators use
819-461: A floor at the same time, are usually driven by the same motor. The system increases efficiency in high-rise buildings, and saves space so additional shafts and cars are not required. In 2003, TK Elevator invented a system called TWIN, with two elevator cars independently running in one shaft. In 1901, consulting engineer Charles G. Darrach (1846–1927) proposed the first formula to determine elevator service. In 1908, Reginald P. Bolton published
910-438: A flywheel and crankshaft to provide rotative motion from an improved Newcomen engine. In 1720, Jacob Leupold described a two-cylinder high-pressure steam engine. The invention was published in his major work "Theatri Machinarum Hydraulicarum". The engine used two heavy pistons to provide motion to a water pump. Each piston was raised by the steam pressure and returned to its original position by gravity. The two pistons shared
1001-423: A given cylinder size than previous engines and could be made small enough for transport applications. Thereafter, technological developments and improvements in manufacturing techniques (partly brought about by the adoption of the steam engine as a power source) resulted in the design of more efficient engines that could be smaller, faster, or more powerful, depending on the intended application. The Cornish engine
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#17327724644191092-416: A large extent displaced by more economical water tube boilers in the late 19th century for marine propulsion and large stationary applications. Many boilers raise the temperature of the steam after it has left that part of the boiler where it is in contact with the water. Known as superheating it turns ' wet steam ' into ' superheated steam '. It avoids the steam condensing in the engine cylinders, and gives
1183-539: A more compact system. The IGBT also allowed the development of a small, highly integrated, highly sophisticated all-digital control device, consisting of a high-speed processor, specially customized gate arrays, and a circuit capable of controlling large currents of several kHz. In 2000, the first vacuum elevator was offered commercially in Argentina. Some people argue that elevators began as simple rope or chain hoists (see Traction elevators below). An elevator
1274-580: A novel tourist attraction which they called the "ascending room", which elevated customers to a considerable height in the center of London, providing a panoramic view. Early, crude steam-driven elevators were refined in the ensuing decade. In 1835, an innovative elevator, the Teagle, was developed by the company Frost and Stutt in England . It was belt-driven and used a counterweight for extra power. In 1845, Neapolitan architect Gaetano Genovese installed
1365-409: A partial vacuum by condensing steam under a piston within a cylinder. It was employed for draining mine workings at depths originally impractical using traditional means, and for providing reusable water for driving waterwheels at factories sited away from a suitable "head". Water that passed over the wheel was pumped up into a storage reservoir above the wheel. In 1780 James Pickard patented the use of
1456-405: A piston into the partial vacuum generated by condensing steam, instead of the pressure of expanding steam. The engine cylinders had to be large because the only usable force acting on them was atmospheric pressure . Watt developed his engine further, modifying it to provide a rotary motion suitable for driving machinery. This enabled factories to be sited away from rivers, and accelerated
1547-433: A set speed, because it would assume a new constant speed in response to load changes. The governor was able to handle smaller variations such as those caused by fluctuating heat load to the boiler. Also, there was a tendency for oscillation whenever there was a speed change. As a consequence, engines equipped only with this governor were not suitable for operations requiring constant speed, such as cotton spinning. The governor
1638-522: A significantly higher efficiency . In a steam engine, a piston or steam turbine or any other similar device for doing mechanical work takes a supply of steam at high pressure and temperature and gives out a supply of steam at lower pressure and temperature, using as much of the difference in steam energy as possible to do mechanical work. These "motor units" are often called 'steam engines' in their own right. Engines using compressed air or other gases differ from steam engines only in details that depend on
1729-577: A small cabinet houses the controller. The equipment is otherwise similar to that of a normal traction or hole-less hydraulic elevator. The world's first machine-room-less elevator, the Kone MonoSpace, was introduced in the year 1996, by Kone . Compared to traditional elevators, it: Its disadvantage was that it could be harder, and significantly more dangerous, to service and maintain. Double-decker elevators are traction elevators with cars that have an upper and lower deck. Both decks, which can serve
1820-460: A so-called 'flying chair' built for one of his mistresses at the Château de Versailles in 1743. Ancient and medieval elevators used drive systems based on hoists and windlasses . The invention of a system based on the screw drive was perhaps the most important step in elevator technology since ancient times, leading to the creation of modern passenger elevators. The first screw-drive elevator
1911-414: A steam jet usually supplied from the boiler. Injectors became popular in the 1850s but are no longer widely used, except in applications such as steam locomotives. It is the pressurization of the water that circulates through the steam boiler that allows the water to be raised to temperatures well above 100 °C (212 °F) boiling point of water at one atmospheric pressure, and by that means to increase
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#17327724644192002-628: A steam rail locomotive was designed and constructed by steamboat pioneer John Fitch in the United States probably during the 1780s or 1790s. His steam locomotive used interior bladed wheels guided by rails or tracks. The first full-scale working railway steam locomotive was built by Richard Trevithick in the United Kingdom and, on 21 February 1804, the world's first railway journey took place as Trevithick's steam locomotive hauled 10 tones of iron, 70 passengers and five wagons along
2093-588: A successful elevator enterprise in Austria-Hungary. The safety and speed of electric elevators were significantly enhanced by Frank Sprague , who added floor control, automatic operation, acceleration control, and further safety devices. His elevator ran faster and with larger loads than hydraulic or steam elevators. 584 of Sprague's elevators were installed before he sold his company to the Otis Elevator Company in 1895. Sprague also developed
2184-612: A trio of locomotives, concluding with the Catch Me Who Can in 1808. Only four years later, the successful twin-cylinder locomotive Salamanca by Matthew Murray was used by the edge railed rack and pinion Middleton Railway . In 1825 George Stephenson built the Locomotion for the Stockton and Darlington Railway . This was the first public steam railway in the world and then in 1829, he built The Rocket which
2275-420: A variety of factors. Hydraulic elevators are cheaper, but installing cylinders greater than a certain length becomes impractical for very-high lift hoistways. For buildings of much over seven floors, traction elevators must be employed instead. Hydraulic elevators are usually slower than traction elevators. Elevators are a candidate for mass customization . There are economies to be made from mass production of
2366-409: A vertical cylinder, allowing the platform, carrying a heavy load, to be raised and lowered. Counterweights and balances were also used to increase lifting power. Henry Waterman of New York is credited with inventing the "standing rope control" for an elevator in 1850. In 1852, Elisha Otis introduced the safety elevator, which prevented the fall of the cab if the cable broke. He demonstrated it at
2457-561: A very limited lift height and were prone to boiler explosions . Savery's engine was used in mines, pumping stations and supplying water to water wheels powering textile machinery. One advantage of Savery's engine was its low cost. Bento de Moura Portugal introduced an improvement of Savery's construction "to render it capable of working itself", as described by John Smeaton in the Philosophical Transactions published in 1751. It continued to be manufactured until
2548-473: A water pump for draining inundated mines. Frenchman Denis Papin did some useful work on the steam digester in 1679, and first used a piston to raise weights in 1690. The first commercial steam-powered device was a water pump, developed in 1698 by Thomas Savery . It used condensing steam to create a vacuum which raised water from below and then used steam pressure to raise it higher. Small engines were effective though larger models were problematic. They had
2639-451: Is a heat engine that performs mechanical work using steam as its working fluid . The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder . This pushing force can be transformed by a connecting rod and crank into rotational force for work. The term "steam engine" is most commonly applied to reciprocating engines as just described, although some authorities have also referred to
2730-426: Is applied in high-speed elevators worldwide. The Toshiba company continued research on thyristors for use in inverter control and dramatically enhanced their switching capacity, resulting in the development of insulated gate bipolar transistors (IGBTs) at the end of the 1980s. The IGBT realized increased switching frequency and reduced magnetic noise in the motor, eliminating the need for a filter circuit and allowing
2821-431: Is cylinder condensation and re-evaporation. The steam cylinder and adjacent metal parts/ports operate at a temperature about halfway between the steam admission saturation temperature and the saturation temperature corresponding to the exhaust pressure. As high-pressure steam is admitted into the working cylinder, much of the high-temperature steam is condensed as water droplets onto the metal surfaces, significantly reducing
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2912-446: Is essentially a platform that is either pulled or pushed up by mechanical means. A modern-day elevator consists of a cab (also called a "cabin", "cage", "carriage" or "car") mounted on a platform within an enclosed space called a shaft or sometimes a "hoistway". In the past, elevator drive mechanisms were powered by steam and water hydraulic pistons or by hand. In a "traction" elevator, cars are pulled up by means of rolling steel ropes over
3003-518: Is in the works of the Roman architect Vitruvius , who reported that Archimedes ( c. 287 BC – c. 212 BC ) built his first elevator probably in 236 BC. Sources from later periods mention elevators as cabs on a hemp rope, powered by people or animals. The Roman Colosseum , completed in 80 AD, had roughly 25 elevators that were used for raising animals up to the floor. Each elevator could carry about 600 pounds (270 kg) (roughly
3094-399: Is then pumped back up to pressure and sent back to the boiler. A dry-type cooling tower is similar to an automobile radiator and is used in locations where water is costly. Waste heat can also be ejected by evaporative (wet) cooling towers, which use a secondary external water circuit that evaporates some of flow to the air. River boats initially used a jet condenser in which cold water from
3185-576: Is thought to be the first office building with passenger elevators. In 1872, American inventor James Wayland patented a novel method of securing elevator shafts with doors that are automatically opened and closed as the elevator car approaches and leaves them. In 1874, J. W. Meaker patented a method permitting elevator doors to open and close safely. The first electric elevator was built by Werner von Siemens in 1880 in Germany. Inventor Anton Freissler further developed von Siemens' ideas and created
3276-542: Is vented up the chimney so as to increase the draw on the fire, which greatly increases engine power, but reduces efficiency. Sometimes the waste heat from the engine is useful itself, and in those cases, very high overall efficiency can be obtained. Steam engines in stationary power plants use surface condensers as a cold sink. The condensers are cooled by water flow from oceans, rivers, lakes, and often by cooling towers which evaporate water to provide cooling energy removal. The resulting condensed hot water ( condensate ),
3367-468: The Rumford Medal , the committee said that "no one invention since Watt's time has so enhanced the efficiency of the steam engine". In addition to using 30% less steam, it provided more uniform speed due to variable steam cut off, making it well suited to manufacturing, especially cotton spinning. The first experimental road-going steam-powered vehicles were built in the late 18th century, but it
3458-399: The piston or turbine machinery alone, as in the beam engine and stationary steam engine . As noted, steam-driven devices such as the aeolipile were known in the first century AD, and there were a few other uses recorded in the 16th century. In 1606 Jerónimo de Ayanz y Beaumont patented his invention of the first steam-powered water pump for draining mines. Thomas Savery is considered
3549-567: The steam turbine and devices such as Hero's aeolipile as "steam engines". The essential feature of steam engines is that they are external combustion engines , where the working fluid is separated from the combustion products. The ideal thermodynamic cycle used to analyze this process is called the Rankine cycle . In general usage, the term steam engine can refer to either complete steam plants (including boilers etc.), such as railway steam locomotives and portable engines , or may refer to
3640-626: The tramway from the Pen-y-darren ironworks, near Merthyr Tydfil to Abercynon in south Wales . The design incorporated a number of important innovations that included using high-pressure steam which reduced the weight of the engine and increased its efficiency. Trevithick visited the Newcastle area later in 1804 and the colliery railways in north-east England became the leading centre for experimentation and development of steam locomotives. Trevithick continued his own experiments using
3731-482: The "Flying chair", an elevator ahead of its time in the Royal Palace of Caserta . It was covered with chestnut wood outside and with maple wood inside. It included a light, two benches, and a hand-operated signal, and could be activated from the outside, without any effort by the occupants. Traction was controlled by a motor mechanic utilizing a system of toothed wheels. A safety system was designed to take effect if
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3822-514: The 1860s to the 1920s. Steam road vehicles were used for many applications. In the 20th century, the rapid development of internal combustion engine technology led to the demise of the steam engine as a source of propulsion of vehicles on a commercial basis, with relatively few remaining in use beyond the Second World War . Many of these vehicles were acquired by enthusiasts for preservation, and numerous examples are still in existence. In
3913-562: The 1960s, the air pollution problems in California gave rise to a brief period of interest in developing and studying steam-powered vehicles as a possible means of reducing the pollution. Apart from interest by steam enthusiasts, the occasional replica vehicle, and experimental technology, no steam vehicles are in production at present. Near the end of the 19th century, compound engines came into widespread use. Compound engines exhausted steam into successively larger cylinders to accommodate
4004-408: The 20th century, where their efficiency, higher speed appropriate to generator service, and smooth rotation were advantages. Today most electric power is provided by steam turbines. In the United States, 90% of the electric power is produced in this way using a variety of heat sources. Steam turbines were extensively applied for propulsion of large ships throughout most of the 20th century. Although
4095-588: The New York exposition in the Crystal Palace in a dramatic, death-defying presentation in 1854, and the first such passenger elevator was installed at 488 Broadway in New York City on 23 March 1857. The first elevator shaft preceded the first elevator by four years. Construction for Peter Cooper 's Cooper Union Foundation building in New York began in 1853. An elevator shaft was included in
4186-610: The amount of work obtained per unit of fuel consumed. By the 19th century, stationary steam engines powered the factories of the Industrial Revolution . Steam engines replaced sails for ships on paddle steamers , and steam locomotives operated on the railways. Reciprocating piston type steam engines were the dominant source of power until the early 20th century. The efficiency of stationary steam engine increased dramatically until about 1922. The highest Rankine Cycle Efficiency of 91% and combined thermal efficiency of 31%
4277-475: The atmosphere or into a condenser. As steam expands in passing through a high-pressure engine, its temperature drops because no heat is being added to the system; this is known as adiabatic expansion and results in steam entering the cylinder at high temperature and leaving at lower temperature. This causes a cycle of heating and cooling of the cylinder with every stroke, which is a source of inefficiency. The dominant efficiency loss in reciprocating steam engines
4368-404: The boiler and engine in separate buildings some distance apart. For portable or mobile use, such as steam locomotives , the two are mounted together. The widely used reciprocating engine typically consisted of a cast-iron cylinder, piston, connecting rod and beam or a crank and flywheel, and miscellaneous linkages. Steam was alternately supplied and exhausted by one or more valves. Speed control
4459-416: The calculations are harder to develop and implement. For very complex systems, the solution is to simulate the building. In this method, a virtual version of a building is created on a computer, modeling passengers and elevators as realistically as possible, and random numbers are used to model probability rather than mathematical equations and percentage probability. Steam power A steam engine
4550-500: The car does not reach maximum rated speed or acceleration, and added the functionality of express zones. This equation is now referred to as the 'Up peak Calculation' as it uses the assumption that all the passengers are coming into the building from the ground floor (incoming traffic) and that there are no passengers traveling from a higher floor to the ground floor (outgoing traffic) and no passengers traveling from one internal floor to another (interfloor traffic). This model works well if
4641-688: The car passed through them. The first elevator in India was installed at the Raj Bhavan in Kolkata by Otis in 1892. By 1900, completely automated elevators were available, but passengers were reluctant to use them. Their adoption was aided by a 1945 elevator operator strike in New York City, and the addition of an emergency stop button, emergency telephone, and a soothing explanatory automated voice. An inverter-controlled gearless drive system
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#17327724644194732-485: The components, but each building comes with its own requirements like different number of floors, dimensions of the well and usage patterns. Elevator doors prevent riders from falling into, entering, or tampering with anything in the shaft. The most common configuration is to have two panels that meet in the middle and slide open laterally. These are known as "center-opening". In a cascading telescopic configuration (potentially allowing wider entryways within limited space),
4823-463: The cords broke, consisting of a beam pushed outwards by a steel spring. The hydraulic crane was invented by Sir William Armstrong in 1846, primarily for use at the Tyneside docks for loading cargo. They quickly supplanted the earlier steam-driven elevators, exploiting Pascal's law to provide much greater force. A water pump supplied a variable level of water pressure to a plunger encased inside
4914-590: The design because Cooper was confident that a safe passenger elevator would soon be invented. The shaft was cylindrical because Cooper thought it was the most efficient design. Otis later designed a special elevator for the building. Peter Ellis , an English architect, installed the first elevators that could be described as paternoster elevators in Oriel Chambers in Liverpool in 1868. The Equitable Life Building , completed in 1870 in New York City,
5005-409: The doors roll on independent tracks so that while open, they are tucked behind one another, and while closed, they form cascading layers on one side. This can be configured so that two sets of such cascading doors operate like the center opening doors described above, allowing for a very wide elevator cab. In less expensive installations the elevator can also use one large "slab" door: a single panel door
5096-401: The efficiency of the steam cycle. For safety reasons, nearly all steam engines are equipped with mechanisms to monitor the boiler, such as a pressure gauge and a sight glass to monitor the water level. Many engines, stationary and mobile, are also fitted with a governor to regulate the speed of the engine without the need for human interference. The most useful instrument for analyzing
5187-452: The elevator shaft when the car was not being entered or exited. In 1887, American inventor Alexander Miles of Duluth, Minnesota , patented an elevator with automatic doors that closed off the elevator shaft when the car was not being entered or exited. In 1891, American inventors Joseph Kelly and William L. Woods co-patented a novel way to guard elevator shafts against accident, by way of hatches that would automatically open and close as
5278-482: The equations had now become so complex that it was almost impossible to do manually and it became necessary to use software to run the calculations. The GA formula was extended even further in 1996 to account for double deck elevators. RTT calculations establish an elevator system's handling capacity by using a set of repeatable calculations which, for a given set of inputs, always produce the same answer. It works well for simple systems; but as systems get more complex,
5369-491: The first book devoted to this subject, Elevator Service . The summation of his work was a massive fold-out chart (placed at the back of his book) that allowed users to determine the number of express and local elevators needed for a given building to meet a desired interval of service. In 1912, commercial engineer Edmund F. Tweedy and electrical engineer Arthur Williams co-authored a book titled Commercial Engineering for Central Stations . He followed Bolton's lead and developed
5460-463: The higher volumes at reduced pressures, giving improved efficiency. These stages were called expansions, with double- and triple-expansion engines being common, especially in shipping where efficiency was important to reduce the weight of coal carried. Steam engines remained the dominant source of power until the early 20th century, when advances in the design of the steam turbine , electric motors , and internal combustion engines gradually resulted in
5551-818: The idea and technology for multiple elevators in a single shaft. In 1871, when hydraulic power was a well established technology, Edward B. Ellington founded Wharves and Warehouses Steam Power and Hydraulic Pressure Company, which became the London Hydraulic Power Company in 1883. It constructed a network of high-pressure mains on both sides of the Thames which ultimately extended 184 miles (296 km) and powered some 8,000 machines, predominantly elevators and cranes. Schuyler Wheeler patented his electric elevator design in 1883. In 1884, American inventor D. Humphreys of Norfolk, Virginia , patented an elevator with automatic doors that closed off
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#17327724644195642-461: The introduction of steel beam construction, worked together to provide the passenger and freight elevators in use today. Starting in coal mines, elevators in the mid-19th century operated with steam power , and were used for moving goods in bulk in mines and factories. These devices were soon applied to a diverse set of purposes. In 1823, Burton and Homer, two architects in London , built and operated
5733-402: The inventor of the first commercially used steam powered device, a steam pump that used steam pressure operating directly on the water. The first commercially successful engine that could transmit continuous power to a machine was developed in 1712 by Thomas Newcomen . James Watt made a critical improvement in 1764, by removing spent steam to a separate vessel for condensation, greatly improving
5824-429: The late 18th century. At least one engine was still known to be operating in 1820. The first commercially successful engine that could transmit continuous power to a machine was the atmospheric engine , invented by Thomas Newcomen around 1712. It improved on Savery's steam pump, using a piston as proposed by Papin. Newcomen's engine was relatively inefficient, and mostly used for pumping water. It worked by creating
5915-399: The nature of the gas although compressed air has been used in steam engines without change. As with all heat engines, the majority of primary energy must be emitted as waste heat at relatively low temperature. The simplest cold sink is to vent the steam to the environment. This is often used on steam locomotives to avoid the weight and bulk of condensers. Some of the released steam
6006-518: The pace of the Industrial Revolution. The meaning of high pressure, together with an actual value above ambient, depends on the era in which the term was used. For early use of the term Van Reimsdijk refers to steam being at a sufficiently high pressure that it could be exhausted to atmosphere without reliance on a vacuum to enable it to perform useful work. Ewing 1894 , p. 22 states that Watt's condensing engines were known, at
6097-456: The performance of steam engines is the steam engine indicator. Early versions were in use by 1851, but the most successful indicator was developed for the high speed engine inventor and manufacturer Charles Porter by Charles Richard and exhibited at London Exhibition in 1862. The steam engine indicator traces on paper the pressure in the cylinder throughout the cycle, which can be used to spot various problems and calculate developed horsepower. It
6188-456: The piston axis in vertical position. In time the horizontal arrangement became more popular, allowing compact, but powerful engines to be fitted in smaller spaces. The acme of the horizontal engine was the Corliss steam engine , patented in 1849, which was a four-valve counter flow engine with separate steam admission and exhaust valves and automatic variable steam cutoff. When Corliss was given
6279-457: The principles of hydraulics (in the sense of hydraulic power ) to pressurize an above-ground or in-ground piston to raise and lower the car (see Hydraulic elevators below). Roped hydraulics use a combination of both ropes and hydraulic power to raise and lower cars. Recent innovations include permanent magnet motors, machine room-less rail mounted gearless machines, and microprocessor controls. The technology used in new installations depends on
6370-406: The reciprocating steam engine is no longer in widespread commercial use, various companies are exploring or exploiting the potential of the engine as an alternative to internal combustion engines. There are two fundamental components of a steam plant: the boiler or steam generator , and the "motor unit", referred to itself as a "steam engine". Stationary steam engines in fixed buildings may have
6461-417: The replacement of reciprocating (piston) steam engines, with merchant shipping relying increasingly upon diesel engines , and warships on the steam turbine. As the development of steam engines progressed through the 18th century, various attempts were made to apply them to road and railway use. In 1784, William Murdoch , a Scottish inventor, built a model steam road locomotive. An early working model of
6552-578: The river is injected into the exhaust steam from the engine. Cooling water and condensate mix. While this was also applied for sea-going vessels, generally after only a few days of operation the boiler would become coated with deposited salt, reducing performance and increasing the risk of a boiler explosion. Starting about 1834, the use of surface condensers on ships eliminated fouling of the boilers, and improved engine efficiency. Evaporated water cannot be used for subsequent purposes (other than rain somewhere), whereas river water can be re-used. In all cases,
6643-412: The steam plant boiler feed water, which must be kept pure, is kept separate from the cooling water or air. Most steam boilers have a means to supply water whilst at pressure, so that they may be run continuously. Utility and industrial boilers commonly use multi-stage centrifugal pumps ; however, other types are used. Another means of supplying lower-pressure boiler feed water is an injector , which uses
6734-489: The temperature of the steam above its saturated vapour point, and various mechanisms to increase the draft for fireboxes. When coal is used, a chain or screw stoking mechanism and its drive engine or motor may be included to move the fuel from a supply bin (bunker) to the firebox. The heat required for boiling the water and raising the temperature of the steam can be derived from various sources, most commonly from burning combustible materials with an appropriate supply of air in
6825-412: The theory of probabilities and found a reasonably accurate method of calculating the average stop count. The equation in this article assumed a consistent population on every floor. He went on to write an updated version of his equations in 1926 which accounted for variable population on each floor. Jones credited David Lindquist for the development of the equation but provides no indication as to when it
6916-482: The time, as low pressure compared to high pressure, non-condensing engines of the same period. Watt's patent prevented others from making high pressure and compound engines. Shortly after Watt's patent expired in 1800, Richard Trevithick and, separately, Oliver Evans in 1801 introduced engines using high-pressure steam; Trevithick obtained his high-pressure engine patent in 1802, and Evans had made several working models before then. These were much more powerful for
7007-512: The weight of two lions) 23 feet (7.0 m) up when powered by up to eight men. In 1000, the Book of Secrets by Ibn Khalaf al-Muradi in Islamic Spain described the use of an elevator-like lifting device to raise a large battering ram to destroy a fortress. In the 17th century, prototypes of elevators were installed in the palace buildings of England and France. Louis XV of France had
7098-403: The width of the doorway that opens to the left or right laterally. These are known as "single slide" doors. Some buildings have elevators with the single door on the shaftway, and double cascading doors on the cab. Elevators that do not require separate machine rooms are designed so that most of their power and control components fit within the hoistway (the shaft containing the elevator car), and
7189-554: Was built by Ivan Kulibin and installed in the Winter Palace in 1793, although there may have been an earlier design by Leonardo da Vinci . Several years later, another of Kulibin's elevators was installed in the Arkhangelskoye near Moscow . The development of elevators was led by the need for movement of raw materials, including coal and lumber , from hillsides. The technology developed by these industries, and
7280-560: Was delayed after the developers went into receivership. It officially opened on 15 November 1991 without any tenants. The first shop moved in in February 1992. In January 2022 the upper three levels of the car park were closed after structural defects were found in the concrete supports. This reduced the number of spaces has been reduced from 270 to 93. 57°38′57″N 3°18′56″W / 57.64928367°N 3.31545892°W / 57.64928367; -3.31545892 This article about
7371-572: Was demonstrated and published in 1921 and 1928. Advances in the design of electric motors and internal combustion engines resulted in the gradual replacement of steam engines in commercial usage. Steam turbines replaced reciprocating engines in power generation, due to lower cost, higher operating speed, and higher efficiency. Note that small scale steam turbines are much less efficient than large ones. As of 2023 , large reciprocating piston steam engines are still being manufactured in Germany. As noted, one recorded rudimentary steam-powered engine
7462-546: Was developed by Trevithick and others in the 1810s. It was a compound cycle engine that used high-pressure steam expansively, then condensed the low-pressure steam, making it relatively efficient. The Cornish engine had irregular motion and torque through the cycle, limiting it mainly to pumping. Cornish engines were used in mines and for water supply until the late 19th century. Early builders of stationary steam engines considered that horizontal cylinders would be subject to excessive wear. Their engines were therefore arranged with
7553-450: Was either automatic, using a governor, or by a manual valve. The cylinder casting contained steam supply and exhaust ports. Engines equipped with a condenser are a separate type than those that exhaust to the atmosphere. Other components are often present; pumps (such as an injector ) to supply water to the boiler during operation, condensers to recirculate the water and recover the latent heat of vaporisation, and superheaters to raise
7644-531: Was entered in and won the Rainhill Trials . The Liverpool and Manchester Railway opened in 1830 making exclusive use of steam power for both passenger and freight trains. Steam locomotives continued to be manufactured until the late twentieth century in places such as China and the former East Germany (where the DR Class 52.80 was produced). The final major evolution of the steam engine design
7735-448: Was first proposed. Although the equations were there, elevator traffic analysis was still a very specialist task that could only be done by world experts. That was until 1967 when Strakosch wrote an eight step method for finding the efficiency of a system in "Vertical transportation: Elevators and Escalators". In 1975, Barney and Dos Santos developed and published the "Round Trip Time (RTT) formula", which followed Strakosch's work. This
7826-411: Was improved over time and coupled with variable steam cut off, good speed control in response to changes in load was attainable near the end of the 19th century. In a simple engine, or "single expansion engine" the charge of steam passes through the entire expansion process in an individual cylinder, although a simple engine may have one or more individual cylinders. It is then exhausted directly into
7917-479: Was not until after Richard Trevithick had developed the use of high-pressure steam, around 1800, that mobile steam engines became a practical proposition. The first half of the 19th century saw great progress in steam vehicle design, and by the 1850s it was becoming viable to produce them on a commercial basis. This progress was dampened by legislation which limited or prohibited the use of steam-powered vehicles on roads. Improvements in vehicle technology continued from
8008-496: Was routinely used by engineers, mechanics and insurance inspectors. The engine indicator can also be used on internal combustion engines. See image of indicator diagram below (in Types of motor units section). The centrifugal governor was adopted by James Watt for use on a steam engine in 1788 after Watt's partner Boulton saw one on the equipment of a flour mill Boulton & Watt were building. The governor could not actually hold
8099-763: Was the aeolipile described by Hero of Alexandria , a Hellenistic mathematician and engineer in Roman Egypt during the first century AD. In the following centuries, the few steam-powered engines known were, like the aeolipile, essentially experimental devices used by inventors to demonstrate the properties of steam. A rudimentary steam turbine device was described by Taqi al-Din in Ottoman Egypt in 1551 and by Giovanni Branca in Italy in 1629. The Spanish inventor Jerónimo de Ayanz y Beaumont received patents in 1606 for 50 steam-powered inventions, including
8190-506: Was the first formulized mathematical model and is the simplest form that is still used by traffic analyzers today. Modification and improvements have been made to this equation over the years, most significantly in 2000 when Peters published "Improvements to the Up Peak Round Trip Time Calculation" which improved the accuracy of the flight time calculation, making allowances for short elevator journeys when
8281-438: Was the use of steam turbines starting in the late part of the 19th century. Steam turbines are generally more efficient than reciprocating piston type steam engines (for outputs above several hundred horsepower), have fewer moving parts, and provide rotary power directly instead of through a connecting rod system or similar means. Steam turbines virtually replaced reciprocating engines in electricity generating stations early in
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