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Uniflow Steam Engine
The uniflow type of steam engine uses steam that flows in one direction only in each half of the cylinder. Thermal efficiency is increased by having a temperature gradient along the cylinder. Steam always enters at the hot ends of the cylinder and exhausts through ports at the cooler centre. By this means, the relative heating and cooling of the cylinder walls is reduced. Design details Steam entry is usually controlled by poppet valves (which act similarly to those used in internal combustion engines) that are operated by a camshaft. The inlet valves open to admit steam when minimum expansion volume has been reached at the start of the stroke. For a period of the crank cycle, steam is admitted, and the poppet inlet is then closed, allowing continued expansion of the steam during the stroke, driving the piston. Near the end of the stroke, the piston will uncover a ring of exhaust ports mounted radially around the centre of the cylinder. These ports are connected by a manifold an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uniflow Steam Engine
The uniflow type of steam engine uses steam that flows in one direction only in each half of the cylinder. Thermal efficiency is increased by having a temperature gradient along the cylinder. Steam always enters at the hot ends of the cylinder and exhausts through ports at the cooler centre. By this means, the relative heating and cooling of the cylinder walls is reduced. Design details Steam entry is usually controlled by poppet valves (which act similarly to those used in internal combustion engines) that are operated by a camshaft. The inlet valves open to admit steam when minimum expansion volume has been reached at the start of the stroke. For a period of the crank cycle, steam is admitted, and the poppet inlet is then closed, allowing continued expansion of the steam during the stroke, driving the piston. Near the end of the stroke, the piston will uncover a ring of exhaust ports mounted radially around the centre of the cylinder. These ports are connected by a manifold an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steam Wagon
A steam wagon (or steam lorry, steam waggon or steamtruck) is a steam-powered truck for carrying freight. It was the earliest form of lorry (truck) and came in two basic forms: ''overtype'' and ''undertype'', the distinction being the position of the engine relative to the boiler. Manufacturers tended to concentrate on one form or the other. Steam wagons were a widespread form of powered road traction for commercial haulage in the early part of the twentieth century, although they were a largely British phenomenon, with few manufacturers outside Great Britain. Competition from internal-combustion-powered vehicles and adverse legislation meant that few remained in commercial use beyond the Second World War. Although the majority of steam wagons have been scrapped, a significant number have been preserved in working order and may be seen in operation at steam fairs, particularly in the UK. Design features The steam wagon came in two basic forms. The ''overtype'' designs looked ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piston Engines
A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert high temperature and high pressure into a rotating motion. This article describes the common features of all types. The main types are: the internal combustion engine, used extensively in motor vehicles; the steam engine, the mainstay of the Industrial Revolution; and the Stirling engine for niche applications. Internal combustion engines are further classified in two ways: either a spark-ignition (SI) engine, where the spark plug initiates the combustion; or a compression-ignition (CI) engine, where the air within the cylinder is compressed, thus heating it, so that the heated air ignites fuel that is injected then or earlier.''Thermodynamics: An Engineering Approach'' by Yunus A. Cengal and Michael A. Boles Common features in all types There may be one or more pistons. Each piston is inside a cylinder, into which a gas is int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steam Engines
A steam engine 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 generally applied only to reciprocating engines as just described, not to the steam turbine. Steam engines 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 the piston or turbine machinery alone, as in the beam engine and stationary steam engine. Although steam-driven devices were known as early as the aeolipile in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Advanced Steam Technology
Advanced steam technology (sometimes known as modern steam) reflects an approach to the technical development of the steam engine intended for a wider variety of applications than has recently been the case. Particular attention has been given to endemic problems that led to the demise of steam power in small- to medium-scale commercial applications: excessive pollution, maintenance costs, labour-intensive operation, low power/weight ratio, and low overall thermal efficiency; where steam power has generally now been superseded by the internal combustion engine or by electrical power drawn from an electrical grid. The only steam installations that are in widespread use are the highly efficient thermal power plants used for generating electricity on a large scale. In contrast, the proposed steam engines may be for stationary, road, rail or marine use. Improving steam traction Although most references to "Modern Steam" apply to developments since the 1970s, certain aspects of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bash Valve
A bash valve is a valve within a piston engine, used to control the admission of the working fluid.Bash Valve - description They are directly actuated valves, operated by contact between the piston and the valve tip. Bash valves have the advantage of great simplicity, for manufacture and operation. Their disadvantages are that their opening and closing times are relatively crudely controlled, compared to other types of . The valve is usually constructed as a circular with a conical seat, inserted into the cylinder from the outside. A protrusion on the inside is hit b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-stroke
A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being completed in one revolution of the crankshaft. A four-stroke engine requires four strokes of the piston to complete a power cycle during two crankshaft revolutions. In a two-stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust (or scavenging) functions occurring at the same time. Two-stroke engines often have a high power-to-weight ratio, power being available in a narrow range of rotational speeds called the power band. Two-stroke engines have fewer moving parts than four-stroke engines. History The first commercial two-stroke engine involving cylinder compression is attributed to Scottish engineer Dugald Clerk, who patented his design in 1881. However, unlike most later t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bash Valve
A bash valve is a valve within a piston engine, used to control the admission of the working fluid.Bash Valve - description They are directly actuated valves, operated by contact between the piston and the valve tip. Bash valves have the advantage of great simplicity, for manufacture and operation. Their disadvantages are that their opening and closing times are relatively crudely controlled, compared to other types of . The valve is usually constructed as a circular with a conical seat, inserted into the cylinder from the outside. A protrusion on the inside is hit b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Cliffs Solar Power Station
White Cliffs Solar Power Station was Australia's first solar power station. It is located at White Cliffs, New South Wales, which was chosen as it has the highest insolation in New South Wales, and in 1981 when the station was constructed had no grid connection. Constructed by a team from Australian National University, the station consisted of fourteen five-metre parabolic dishes, each covered by more than 2000 mirrors and mounted on a heliostatic mounting. The dishes each focussed the sun's rays on a collector, where water was boiled. The resulting steam drove a three-cylinder Uniflow steam engine, made by modifying a Lister diesel engine, delivering up to 25kWe. Batteries were used to provide 24-hour power to selected buildings in the township, and an existing diesel generator retained to provide battery charging when either low insolation or strong winds prevented use of the solar station for extended periods. In 1996, following grid connection of the township, the stat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aircraft Carrier
An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and facilities for carrying, arming, deploying, and recovering aircraft. Typically, it is the capital ship of a fleet, as it allows a naval force to project air power worldwide without depending on local bases for staging aircraft operations. Carriers have evolved since their inception in the early twentieth century from wooden vessels used to deploy balloons to nuclear-powered warships that carry numerous fighters, strike aircraft, helicopters, and other types of aircraft. While heavier aircraft such as fixed-wing gunships and bombers have been launched from aircraft carriers, these aircraft have not successfully landed on a carrier. By its diplomatic and tactical power, its mobility, its autonomy and the variety of its means, the aircraft carrier is often the centerpiece of modern combat fleets. Tactically or even strategically, it replaced the battleship in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Lakes
The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes, which are Superior, Michigan, Huron, Erie, and Ontario and are in general on or near the Canada–United States border. Hydrologically, lakes Michigan and Huron are a single body joined at the Straits of Mackinac. The Great Lakes Waterway enables modern travel and shipping by water among the lakes. The Great Lakes are the largest group of freshwater lakes on Earth by total area and are second-largest by total volume, containing 21% of the world's surface fresh water by volume. The total surface is , and the total volume (measured at the low water datum) is , slightly less than the volume of Lake Baikal (, 22–23% of the world's surface fresh water). Because of their sea-like characteristics, such as rolling waves, sustained wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Train Ferry
A train ferry is a ship (ferry) designed to carry railway vehicles. Typically, one level of the ship is fitted with railway tracks, and the vessel has a door at the front and/or rear to give access to the wharves. In the United States, train ferries are sometimes referred to as "car ferries", as distinguished from "auto ferries" used to transport automobiles. The wharf (sometimes called a " slip") has a ramp, and a linkspan or "apron", balanced by weights, that connects the railway proper to the ship, allowing for tidal or seasonal changes in water level. While railway vehicles can be and are shipped on the decks or in the holds of ordinary ships, purpose-built train ferries can be quickly loaded and unloaded by roll-on/roll-off, especially as several vehicles can be loaded or unloaded at once. A train ferry that is a barge is called a car float or rail barge. History An early train ferry was established as early as 1833 by the Monkland and Kirkintilloch Railway. To exten ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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