Histoire de la machine à vapeurLa première machine à vapeur rudimentaire connue est l'aeolipile décrite par Héron d'Alexandrie dans l'Égypte romaine du Ier siècle. Plusieurs dispositifs à vapeur ont ensuite été expérimentés ou proposés, comme le cric à vapeur de Taqi al-Din, une turbine à vapeur dans l'Égypte ottomane du XVIe siècle, et la pompe à vapeur de Thomas Savery dans l'Angleterre du XVIIe siècle. En 1712, le moteur atmosphérique de Thomas Newcomen est devenu le premier moteur à succès commercial utilisant le principe du piston et du cylindre, qui était le type fondamental de moteur à vapeur utilisé jusqu'au début du 20e siècle.
Single- and double-acting cylindersIn mechanical engineering, the cylinders of reciprocating engines are often classified by whether they are single- or double-acting, depending on how the working fluid acts on the piston. A single-acting cylinder in a reciprocating engine is a cylinder in which the working fluid acts on one side of the piston only. A single-acting cylinder relies on the load, springs, other cylinders, or the momentum of a flywheel, to push the piston back in the other direction. Single-acting cylinders are found in most kinds of reciprocating engine.
Beam engineA beam engine is a type of steam engine where a pivoted overhead beam is used to apply the force from a vertical piston to a vertical connecting rod. This configuration, with the engine directly driving a pump, was first used by Thomas Newcomen around 1705 to remove water from mines in Cornwall. The efficiency of the engines was improved by engineers including James Watt, who added a separate condenser; Jonathan Hornblower and Arthur Woolf, who compounded the cylinders; and William McNaught, who devised a method of compounding an existing engine.
Stationary steam engineStationary 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.
Compound steam engineA compound steam engine unit is a type of steam engine where steam is expanded in two or more stages. A typical arrangement for a compound engine is that the steam is first expanded in a high-pressure (HP) cylinder, then having given up heat and losing pressure, it exhausts directly into one or more larger-volume low-pressure (LP) cylinders. Multiple-expansion engines employ additional cylinders, of progressively lower pressure, to extract further energy from the steam.
