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Valve Gear
The valve gear of a steam engine is the mechanism that operates the inlet and exhaust valves to admit steam into the cylinder and allow exhaust steam to escape, respectively, at the correct points in the cycle. It can also serve as a reversing gear. It is sometimes referred to as the "motion". Purpose In the simple case, this can be a relatively simple task as in the internal combustion engine in which the valves always open and close at the same points. This is not the ideal arrangement for a steam engine, though, because greatest power is achieved by keeping the inlet valve open throughout the power stroke (thus having full boiler pressure, minus transmission losses, against the piston throughout the stroke) while peak efficiency is achieved by only having the inlet valve open for a short time and then letting the steam expand in the cylinder (expansive working). The point at which steam stops being admitted to the cylinder is known as the '' cutoff'', and the optimal posit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walschaerts Valve Gear
The Walschaerts valve gear is a type of valve gear used to regulate the flow of steam to the pistons in steam locomotives, invented by Belgium, Belgian railway mechanical engineering, engineer Egide Walschaerts in 1844. The gear is sometimes named without the final "s", since it was incorrectly patented under that name. It was extensively used in steam locomotives from the late 19th century until the end of the steam era. History The Walschaerts valve gear was slow to gain popularity. The Stephenson valve gear remained the most commonly used valve gear on 19th-century locomotives. However, the Walschaerts valve gear had the advantage that it could be mounted entirely on the outside of the locomotives, leaving the space between the locomotive frame, frames clear and allowing easy access for service and adjustment, which resulted in it being adopted in some articulated locomotives. The first locomotive fitted with the Walschaerts valve gear was built in 1849 at the Belgian Tubiz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase (waves)
In physics and mathematics, the phase (symbol φ or ϕ) of a wave or other periodic function F of some real variable t (such as time) is an angle-like quantity representing the fraction of the cycle covered up to t. It is expressed in such a scale that it varies by one full turn as the variable t goes through each period (and F(t) goes through each complete cycle). It may be measured in any angular unit such as degrees or radians, thus increasing by 360° or 2\pi as the variable t completes a full period. This convention is especially appropriate for a sinusoidal function, since its value at any argument t then can be expressed as \varphi(t), the sine of the phase, multiplied by some factor (the amplitude of the sinusoid). (The cosine may be used instead of sine, depending on where one considers each period to start.) Usually, whole turns are ignored when expressing the phase; so that \varphi(t) is also a periodic function, with the same period as F, that repeatedly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Francis William Webb
Francis William Webb (21 May 1836 – 4 June 1906) was an English railway engineer, responsible for the design and manufacture of locomotives for the London and North Western Railway (LNWR). As the LNWR's chief mechanical engineer, he also exercised great influence in political and public life in the Cheshire town of Crewe, once being described as the 'King of Crewe'. Early life Webb was born in Tixall Rectory, near Stafford, the second son of William Webb, Rector of Tixall. Career Crewe Works Showing early interest in mechanical engineering, on 11 August 1851 at the age of fifteen he was articled as a pupil of Francis Trevithick at Crewe Works.Griffiths, p.51 Webb joined the drawing office in 1856, at the end of his training. He became Chief Draughtsman on 1 March 1859. On 1 September 1861 he was appointed Works Manager at Crewe and Chief Assistant to John Ramsbottom. Whilst Works Manager, Webb was responsible for the installation of Bessemer converters and the star ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
London And North Western Railway
The London and North Western Railway (LNWR, L&NWR) was a British railway company between 1846 and 1922. In the late 19th century, the LNWR was the largest joint stock company in the world. Dubbed the "Premier Line", the LNWR's main line connected four of the largest cities in England; London, Birmingham, Manchester and Liverpool, and, through cooperation with their Scottish partners, the Caledonian Railway also connected Scotland's largest cities of Glasgow and Edinburgh. Today this route is known as the West Coast Main Line. The LNWR's network also extended into Wales and Yorkshire. In 1923, it became a constituent of the London, Midland and Scottish (LMS) railway, and, in 1948, the London Midland Region of British Railways. History The company was formed on 16 July 1846 by the ( 9 & 10 Vict. c. cciv), which authorised the amalgamation of the Grand Junction Railway, London and Birmingham Railway and the Manchester and Birmingham Railway. This move was prompted, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double Beat Valve
The double-beat valve, drop valve or equilibrium valve is a type of poppet valve arranged to allow it to be opened against a high pressure with a minimum of force. One of its uses is in steam engines to admit steam to the cylinders and to release the exhaust. In stationary steam engines it is usually operated by trip valve gear while in railway locomotives a valve gear such as Caprotti valve gear, Caprotti is used. Hornblower's valve It was invented around 1800 by Jonathan Hornblower. His valve is in the form of a hollow cylinder provided with two seats of nearly equal diameter, at ''A'' and ''B'' in the diagram. The cylinder is connected to the actuating rod by a web. The force required to lift the valve depends on the difference between diameters ''D'' and ''d'': the smaller this difference can be made, the less the force necessary to open the valve. In Hornblower's valve, the steam flows past seat ''B'' only. In later developments of the valve, the central portion is waisted so t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corliss Valve
Corliss is both a surname and a given name. People Given name * Corliss Lamont (1902–1995), American philosopher, political activist, and philanthropist * C. C. Moseley (1894–1974), American aviator and aviation businessman * Corliss Palmer (1899–1952), American silent film actress * Corliss P. Stone (1806–1873), mayor of Seattle and businessman * Corliss Waitman (born 1995), Belgian-born American football punter for the Pittsburgh Steelers * Corliss Williamson (born 1973), basketball player Surname * Augustus W. Corliss (1837–1907), American writer, historian and Civil War veteran * George Henry Corliss (1817–1888), inventor of the Corliss steam engine * George W. Corliss (1834–1903), American Civil War recipient of the Medal of Honor * Guy C. H. Corliss (1858–1937), American judge and justice of the Supreme Court of North Dakota * Jack Corliss, scientist and discoverer of undersea hydrothermal vents * Jeb Corliss (born 1976), American skydiver and base ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trip Valve
Trip valve mechanisms are a class of steam engine valve gear developed to improve efficiency. The trip mechanism allows the inlet valve to be closed rapidly, giving a short, sharp cut-off. The valve itself can be a drop valve or a Corliss valve. Trip valve gear was applied to larger stationary engines. It was not used in transport applications,An exception was the very early London Steam Carriage (1803) which had a form of trip gear. as it was not suitable for high speed. The trip point of the valve mechanism, and therefore the cut-off, would be adjusted either manually or automatically by the governor. The valve is opened by the mechanical valve gear mechanism, and when the trip gear trigger releases the mechanism the valve is snapped closed, usually by a spring acting against a dashpot A dashpot, also known as a damper, is a mechanical device that resists motion via viscous damping. The resulting force is proportional to the velocity, but acts in the opposite direction, sl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steam Engine
A steam engine is a heat engine that performs Work (physics), 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 (locomotive), cylinder. This pushing force can be transformed by a connecting rod and Crank (mechanism), 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 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 Boiler (power generation), boilers etc.), such as railway steam locomot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Steam Engine
A marine steam engine is a steam engine that is used to power a ship or boat. This article deals mainly with marine steam engines of the reciprocating type, which were in use from the inception of the steamboat in the early 19th century to their last years of large-scale manufacture during World War II. Reciprocating steam engines were progressively replaced in marine applications during the 20th century by steam turbines and marine diesel engines. History The first commercially successful steam engine was developed by Thomas Newcomen in 1712. The steam engine improvements brought forth by James Watt in the later half of the 18th century greatly improved steam engine efficiency and allowed more compact engine arrangements. Successful adaptation of the steam engine to marine applications in England would have to wait until almost a century after Newcomen, when Scottish engineer William Symington built the world's "first practical steamboat", the '' Charlotte Dundas'', in 1802. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traction Engine
A traction engine is a steam engine, steam-powered tractor used to move heavy loads on roads, plough ground or to provide power at a chosen location. The name derives from the Latin ''tractus'', meaning 'drawn', since the prime function of any traction engine is to draw a load behind it. They are sometimes called road locomotives to distinguish them from railway steam locomotive, locomotives – that is, steam engines that run on rails. Traction engines tend to be large, robust and powerful, but also heavy, slow, and difficult to manoeuvre. Nevertheless, they revolutionized agriculture and road haulage at a time when the only alternative Prime mover (tractor unit), prime mover was the draught horse. They became popular in industrialised countries from around 1850, when the first self-propelled portable steam engines for agricultural use were developed. Production continued well into the early part of the 20th century, when competition from internal combustion engine-powered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stationary Steam Engine
Stationary steam engines are fixed steam engines used for pumping or driving mills and factories, and for power generation. They are distinct from locomotive engines used on railways, traction engines for heavy steam haulage on roads, steam cars (and other motor vehicles), agricultural engines used for ploughing or threshing, marine engines, and the steam turbines used as the mechanism of power generation for most nuclear power plants. They were introduced during the 18th century and widely made for the whole of the 19th century and most of the first half of the 20th century, only declining as electricity supply and the internal combustion engine became more widespread. Types of stationary steam engine There are different patterns of stationary steam engines, distinguished by the layout of the cylinders and crankshaft: * Beam engines have a rocking beam providing the connection between the vertical cylinder and crankshaft. * Table engines have the crosshead above the v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sleeve Valve
The sleeve valve is a type of valve mechanism for piston engines, distinct from the usual poppet valve. Sleeve valve engines saw use in a number of pre–World War II luxury cars and in the United States in the Willys-Knight car and light truck. They subsequently fell from use due to advances in poppet-valve technology, including sodium cooling, and the Knight system double sleeve engine's tendency to burn a lot of lubricating oil or to seize due to lack of it. The Scottish Argyll company used its own, much simpler and more efficient, single sleeve system (Burt-McCollum) in its cars, a system which, after extensive development, saw substantial use in British aircraft engines of the 1940s, such as the Napier Sabre, Bristol Hercules, Centaurus, and the promising but never mass-produced Rolls-Royce Crecy, only to be supplanted by the jet engines. Description A sleeve valve takes the form of one (or in the case of double sleeve valves, two) machined cylinders which fit concentric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
