Steam EnginesSteam Engines

Nathan FiresheetsNathan Firesheets

History of Steam EngineHistory of Steam Engine Inventors used experimental devices, such as the Inventors used experimental devices, such as the

rudimentary rudimentary steam turbinesteam turbine device described by device described by TaqiTaqi al-Din al-Din in 1551 and in 1551 and Giovanni Giovanni BrancaBranca in 1629, to in 1629, to demonstrate the properties of steam.demonstrate the properties of steam.

The first practical steam-powered 'engine' was a The first practical steam-powered 'engine' was a water pump, developed in 1698 by water pump, developed in 1698 by Thomas Thomas SaverySavery. . It proved only to have a limited lift height and was It proved only to have a limited lift height and was prone to prone to boiler explosionsboiler explosions, but it still received some , but it still received some use for mines and use for mines and pumping stationspumping stations. .

The first commercially successful engine, the The first commercially successful engine, the atmospheric engineatmospheric engine, invented by , invented by Thomas Thomas NewcomenNewcomen did not appear until 1712. Newcomen's did not appear until 1712. Newcomen's engine was relatively inefficient, and in most cases engine was relatively inefficient, and in most cases was only used for pumping water. was only used for pumping water.

History of Steam EngineHistory of Steam Engine James WattJames Watt developed an improved version of developed an improved version of

Newcomen's engine between 1763 and 1775 which used Newcomen's engine between 1763 and 1775 which used 75% less coal than Newcomen's, and was hence much 75% less coal than Newcomen's, and was hence much cheaper to run. Watt proceeded to develop his engine cheaper to run. Watt proceeded to develop his engine further, modifying it to provide a rotary motion suitable further, modifying it to provide a rotary motion suitable for driving factory machinery. for driving factory machinery.

Early engines were "atmospheric", meaning that they Early engines were "atmospheric", meaning that they were powered by the were powered by the vacuumvacuum generated by generated by condensingcondensing steam instead of the pressure of expanding steam. steam instead of the pressure of expanding steam. Cylinders had to be large, as the only usable force acting Cylinders had to be large, as the only usable force acting on them was atmospheric pressure. Steam was only used on them was atmospheric pressure. Steam was only used to compensate for the atmosphere allowing the piston to to compensate for the atmosphere allowing the piston to move back to its starting position. Even if pressured move back to its starting position. Even if pressured steam had been available, it could not do any work (push) steam had been available, it could not do any work (push) against the chain connecting the piston to the beam. against the chain connecting the piston to the beam.

Early Watt Steam pumping Early Watt Steam pumping engine. engine.

History of Steam EnginesHistory of Steam Engines Around 1800, Richard Trevithick introduced engines Around 1800, Richard Trevithick introduced engines

using high-pressure steam. These were much more using high-pressure steam. These were much more powerful than previous engines and could be made powerful than previous engines and could be made small enough for transport applications. small enough for transport applications.

Thereafter, technological developments and Thereafter, technological developments and improvements in manufacturing techniques (partly improvements in manufacturing techniques (partly brought about by the adoption of the steam engine as brought about by the adoption of the steam engine as a power source) resulted in the design of more a power source) resulted in the design of more efficient engines that could be smaller, faster, or more efficient engines that could be smaller, faster, or more powerful, depending on the intended application. powerful, depending on the intended application.

Steam engines remained the dominant source of Steam engines remained the dominant source of power well into the 20th century, when advances in power well into the 20th century, when advances in the design of electric motors and internal combustion the design of electric motors and internal combustion engines gradually resulted in the vast majority of engines gradually resulted in the vast majority of reciprocating steam engines being replaced in reciprocating steam engines being replaced in commercial usage, and the ascendancy of steam commercial usage, and the ascendancy of steam turbines in power generation. turbines in power generation.

Rankine CycleRankine Cycle

Rankine CycleRankine Cycle Process 1-2Process 1-2: The working fluid is pumped from low to high pressure, as the fluid is a : The working fluid is pumped from low to high pressure, as the fluid is a

liquid at this stage the pump requires little input energy. liquid at this stage the pump requires little input energy. Process 2-3Process 2-3: The high pressure liquid enters a boiler where it is heated at constant : The high pressure liquid enters a boiler where it is heated at constant

pressure by an external heat source to become a dry saturated vapor. pressure by an external heat source to become a dry saturated vapor. Process 3-4Process 3-4: The dry saturated vapor expands through a : The dry saturated vapor expands through a turbineturbine, generating power. , generating power.

This decreases the temperature and pressure of the vapor, and some condensation may This decreases the temperature and pressure of the vapor, and some condensation may occur. occur.

Process 4-1Process 4-1: The wet vapor then enters a : The wet vapor then enters a condensercondenser where it is condensed at a where it is condensed at a constant pressure and temperature to become a constant pressure and temperature to become a saturated liquidsaturated liquid. The pressure and . The pressure and temperature of the condenser is fixed by the temperature of the cooling coils as the temperature of the condenser is fixed by the temperature of the cooling coils as the fluid is undergoing a fluid is undergoing a phase-changephase-change. .

Basic operation of a simple Basic operation of a simple reciprocating steam enginereciprocating steam engine

Heat is obtained from fuel burnt in a closed Heat is obtained from fuel burnt in a closed fireboxfirebox The heat is transferred to the water in a pressurized The heat is transferred to the water in a pressurized

boilerboiler, ultimately boiling the water and transforming , ultimately boiling the water and transforming it into saturated steam. Steam in its saturated state it into saturated steam. Steam in its saturated state is always produced at the temperature of the boiling is always produced at the temperature of the boiling water, which in turn depends on the steam pressure water, which in turn depends on the steam pressure on the water surface within the boiler. on the water surface within the boiler.

The steam is transferred to the motor unit which The steam is transferred to the motor unit which uses it to push on a uses it to push on a pistonpiston sliding inside a sliding inside a cylindercylinder to power machinery. to power machinery.

The used, cooler, lower pressure steam is exhausted The used, cooler, lower pressure steam is exhausted to atmosphere. to atmosphere.

Double Piston StrokeDouble Piston Stroke

Double Acting Steam Double Acting Steam EngineEngine

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Other Types of Steam Other Types of Steam EnginesEngines

Compounding EnginesCompounding Engines Multiple Expansion EnginesMultiple Expansion Engines Uniflow EnginesUniflow Engines Turbine EnginesTurbine Engines Rotary Steam EnginesRotary Steam Engines Jet-type Steam EnginesJet-type Steam Engines Rocket-type Steam EnginesRocket-type Steam Engines

Triple Expansion EngineTriple Expansion Engine

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Uniflow EngineUniflow Engine

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Turbine EngineTurbine Engine

The Dangers of Steam The Dangers of Steam PowerPower

http://www.youtube.com/watch?v=Cv178a60Ypg

Questions?Questions?