A steam engine is a device that produces mechanical energy through the use of water vapor. In particular, thermal energy is transformed into mechanical energy by means of steam. Heat is typically produced by burning fossil fuels, particularly coal, but it can also come from wood, hydrocarbons or nuclear reactions.
Description of steam engines
An essential part of the system that includes the steam engine is the steam generator, or the boiler. In the boiler water vapor is obtained by the administration of heat to liquid water. The steam is then sent to the engine, which can be of two basic types: alternative or rotary. Alternative engines are used in locomotion machines. Rotary type motors are used to drive turbines.
In the reciprocating engine, the steam moves the actuation valves that allow the two sides of each piston to explode. At each motor rotation it has two active phases. In internal combustion thermal engines there is generally an expansion every 4 phases ( 4-stroke engine).
From the second half of 1800 almost all steam engines used two, three and even four cylinders in series for double expansion and triple expansion engines.
In particular, the triple expansion solution was universally adopted by all ships in the second half of the 800 and the first 900. For example, the Titanic ocean liner was equipped with two triple expansion steam engines, one for each of the two lateral four- cylinder propellers, one high pressure, one medium pressure and two low pressure. In the place of the central propeller was connected to a steam turbine driven by very low pressure steam discharged from the two reciprocating engines.
Only the turbine solution (adopted starting with military vessels since 1905) would have completely supplanted the marine alternative engines before being in turn replaced by internal combustion engines and gas turbines. Steam turbines remain in use mainly in power plants as a driving force for the operation of three-phase alternators.
In fact, in traditional applications, today the steam engine has been almost completely replaced by the internal combustion engine. Regarding the steam engine, the thermal engine is more compact and powerful and does not require the preheating phase to put the boiler under pressure.
Papin steam engines
It was not until the end of the 18th century that there were no reliable and efficient steam engines when the first serious attempts at naval propulsion were made by steam. In 1707 the French inventor Denis Papin designed a ship, moved by the force of steam, with the intention of making the crossing from Kassel, in Germany, to London.
Denis Papin did in medical studies in Angers. He previously worked with Christian Huygens in Leiden, where he tries to develop an air pump. In 1679 he invented the pressure cooker, at the time of deposit, the patent with the words present here digester causes a large amount of digestible amount of food, including hard meat. After working for some time with Robert Boyle, he returned later with Huygens in 1680. After a stay in Venice as director of internships at the 'Ambrosio Sarrotti Academy, and then to the Royal Society of London, he was appointed professor of mathematics at Marburg.
At this point, from the experience of the pressure cooker, Papin builds his first steam engine: a steamboat in 1707. But this magnificent invention involved many controversies by the boatmen who threatened to destroy the ship. Papin later returned to England eventually, where, despite the new research, resources are dwindling.
Last review: November 13, 2017