Why was the steam engine invented

Heat water to its boiling point and it changes from being a liquid to become the gas or water vapor we know as steam. When water becomes steam its volume increases about 1,600 times, that expansion is full of energy.

An engine is a machine that converts energy into mechanical force or motion that can turn pistons and wheels. The purpose of an engine is to provide power, a steam engine provides mechanical power by using the energy of steam.

Steam engines were the first successful engines invented and were the driving force behind the industrial revolution. They have been used to power the first trains, ships, factories, and even cars. And while steam engines were definitely important in the past, they also now have a new future in supplying us with power with geothermal energy sources.

How Steam Engines Work

To understand a basic steam engine, let's take the example of the steam engine found in an old steam locomotive like the one depicted. The basic parts of the steam engine in a locomotive would be a boiler, slide valve, cylinder, steam reservoir, piston, and a drive wheel.

In the boiler, there would be a firebox where coal would be shoveled into. The coal would be kept burning at a very high temperature and used to heat the boiler to boil water producing high-pressure steam. The high-pressure steam expands and exits the boiler via steam pipes into the steam reservoir. The steam is then controlled by a slide valve to move into a cylinder to push the piston. The pressure of the steam energy pushing the piston turns the drive wheel in a circle, creating motion for the locomotive.

History of Steam Engines

Humans have been aware of the power of steam for centuries. Greek engineer, Hero of Alexandria (circa 100 AD), experimented with steam and invented the aeolipile, the first but very crude steam engine. The aeolipile was a metal sphere mounted on top of a boiling water kettle. The steam traveled through pipes to the sphere. Two L-shaped tubes on opposite sides of the sphere released the steam, which gave a thrust to the sphere that caused it to rotate. However, Hero never realized the potential of the aeolipile, and centuries were to pass before a practical steam engine would be invented.

In 1698, English engineer, Thomas Savery patented the first crude steam engine. Savery used his invention to pump water out of a coal mine. In 1712, English engineer and blacksmith, Thomas Newcomen invented the atmospheric steam engine. The purpose of Newcomen's steam engine was also to remove water from mines. In 1765, a Scottish engineer, James Watt began studying Thomas Newcomen's steam engine and invented an improved version. It was Watt's engine that was the first to have a rotary motion. James Watt's design was the one that succeeded and the use of steam engines became widespread.

Steam engines' had a profound effect on the history of transportation. By the late 1700s, inventors realized that steam engines could power boats and the first commercially successful steamship was invented by George Stephenson. After 1900, gasoline and diesel internal combustion engines began replacing the steam piston engines. However, steam engines have reappeared in the last twenty years.

Steam Engines Today

It may be surprising to know that 95 percent of nuclear power plants use steam engines to generate power. Yes, the radioactive fuel rods in a nuclear power plant are used just like coal in a steam locomotive to boil water and create steam energy. However, the disposal of spent radioactive fuel rods, the vulnerability of the nuclear power plants to earthquakes and other issues leaves the public and the environment at great risk.

Geothermal power is power generated using steam produced by heat emanating from the molten core of the earth. Geothermal power plants are relatively green technology. Kaldara Green Energy, a Norwegian/Icelandic manufacturer of geothermal electrical power production equipment, has been the major innovator in the field.

Solar thermal power plants can also use steam turbines to generate their power.

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Bellis, Mary. "How Do Steam Engines Work?" ThoughtCo. https://www.thoughtco.com/steam-engines-history-1991933 (accessed December 22, 2022).

Steam engines are mechanisms that use heat to create steam, which in turn performs mechanical processes, known generally as work. While several inventors and innovators worked on various aspects of using steam for power, the major development of early steam engines involves three inventors and three principal engine designs. 

Thomas Savery and the First Steam Pump

The first steam engine used for work was patented by the Englishman Thomas Savery in 1698 and was used to pump water out of mine shafts. The basic process involved a cylinder that was filled with water. Steam was then delivered to the cylinder, displacing the water, which flowed out through a one-way valve. Once all of the water was ejected, the cylinder was sprayed with cool water to drop the cylinder's temperature and condense the steam inside. This created a vacuum inside the cylinder, which then pulled up additional water to refill the cylinder, completing the pump cycle. 

Thomas Newcomen's Piston Pump

Another Englishman, Thomas Newcomen, improved on Savery's pump with a design he developed around 1712. Newcomen's engine included a piston inside of a cylinder. The top of the piston was connected to one end of a pivoting beam. A pump mechanism was connected to the other end of the beam so that water was drawn up whenever the beam tilted up on the pump end. To propel the pump, steam was delivered to the piston cylinder. At the same time, a counterweight pulled the beam down on the pump end, which made the piston rise to the top of the steam cylinder. Once the cylinder was full of steam, cool water was sprayed inside the cylinder, quickly condensing the steam and creating a vacuum inside the cylinder. This caused the piston to drop, moving the beam down on the piston end and up on the pump end. The cycle then repeated automatically as long as steam was applied to the cylinder. 

Newcomen's piston design effectively created a separation between the water being pumped out and the cylinder used to create the pumping power. This greatly improved on the efficiency of Savery's original design. However, because Savery's held a broad patent on his own steam pump, Newcomen had to collaborate with Savery to patent the piston pump. 

James Watt's Improvements

Scotsman James Watt significantly improved and developed the steam engine over the second half of the 18th century, making it a truly viable piece of machinery that helped start the Industrial Revolution. The first major innovation of Watt's was to include a separate condenser so that the steam didn't have to be cooled in the same cylinder that contained the piston. This meant the piston cylinder remained at a much more consistent temperature, greatly increasing the fuel efficiency of the engine. Watt also developed an engine that could rotate a shaft, rather than an up-and-down pumping action, as well as a flywheel that allowed for smooth power transfer between the engine and the workload. With these and other innovations, the steam engine became applicable to a variety of factory processes, and Watt and his business partner, Matthew Boulton, built several hundred engines for industrial use. 

Later Steam Engines

The early 19th century saw major innovation of high-pressure steam engines, which were much more efficient than the low-pressure designs of Watt's and the others steam-engine pioneers. This led to the development of much smaller, more powerful steam engines that could be used to power trains and boats and to perform a wider range of industrial tasks, such as running saws in mills. Two important innovators of these engines were American Oliver Evans and Englishman Richard Trevithick. Over time, steam engines were replaced by the internal combustion engine for most types of locomotion and industrial work, but the use of steam generators to create electricity remains an important part of electrical power production today. 

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Kelly, Martin. "Invention of the Steam Engine." ThoughtCo. https://www.thoughtco.com/invention-of-the-steam-engine-104723 (accessed December 22, 2022).

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