An external combustion engine that produces mechanical energy through the use of water vapor is called a steam engine. In particular, thermal energy is transformed into mechanical energy generating steam.
Heat is generated by burning fossil fuels. Normally large amounts of coal are used, but it can also come from wood, nuclear reactions, or even solar energy.
It is one of the most important inventions of the industrial revolution in the 19th century.
How does a steam engine work?
The basic operation of a steam engine is based on the following steps:
Generate a heat source to boil the water.
Water turns into steam.
Take advantage of the steam pressure to activate a mechanical mechanism.
Steam generator or boiler
An essential part of the system is the steam generator, or the boiler. In the boiler it is heated to the water and it is converted into steam through the administration of heat. The steam is then sent to the engine, which can be of two basic types:
Reciprocating engine, pushing a piston.
Rotary engine, driving a steam turbine.
Alternative engine of a steam engine
In the reciprocating engine, steam moves the actuation valves that allow the piston to be pushed from both sides. In each rotation of the motor it has two active phases. In internal combustion thermal engines there is generally one expansion every 4 phases ( 4-stroke engine).
Starting in the second half of 1800, almost all steam engines used two, three, and even four cylinders in series for dual and triple expansion engines.
The turbine completely supplanted in marine reciprocating engines. Later, internal combustion engines and gas turbines were replaced. Steam turbines remain in use especially in power plants as the driving force for driving three-phase alternators.
In traditional applications, today the steam engine has been almost completely replaced by the internal combustion engine. Compared to the steam engine, the heat engine is more compact and powerful and does not require the preheating phase to put the boiler on pressure.
Who invented the steam engine?
The inventor of the first steam engine was Thomas Savery in 1698. This first engine was a water pump.
The inventor of the steam engine as we know it today was James Watt (1769).
This first commercial steam engine was a water pump. Savery used condensation steam to create a vacuum that allowed the water to rise from below. Then, pressure was supplied to lift it further.
Savery's engine was used in mines, pumping stations, and supplying water to the hydraulic wheels that powered textile machinery. Savery's steam engine was inexpensive.
Later the first piston steam engine appeared: The first commercially successful engine that could transmit continuous power to a machine was the atmospheric engine, invented by Thomas Newcomen around 1712. Newcomen improved the Savery steam pump, using a piston as Papin suggested it.
The Newcomen machine became the first commercially successful engine using the piston and cylinder principle. This was the fundamental type of steam engine used until the beginning of the 20th century.
It was not until the end of the 18th century that reliable and efficient steam engines existed when the first serious attempts at naval propulsion by steam were made.
James Watt steam engine
James Watt's steam engine is the result of Watt's improvements to the Newcomen machine (1769).
These improvements, in part thanks to Joseph Black's thermodynamic investigations, led to the manufacture of today's steam engine.
Wat was a Scottish mechanical engineer, inventor and chemist educated at the University of Glasgow. Together with the English manufacturer Matthew Boulton they founded the company Boulton and Watt. This company was one of the first in the business of designing and manufacturing steam engines.
In James's honor, the unit of electrical power is called the watt in the international measurement system.
Features of Watt steam engine
It had a separate chamber for steam condensation.
The costs were lower than those of the Newcomen machine.
It avoided the loss of steam produced in each cycle. To do this, Watt isolated the cylinder so that it remained at the temperature of the steam.
The separate condensation chamber was air-cooled.
In the condensation chamber included a pump to make a vacuum to absorb the steam from the cylinder to the condenser.
It worked with steam pressure instead of atmospheric pressure to get motion.
It allowed to convert the linear movement of the pistons into a circular movement.
It had butterfly valves to limit speed. It also had regulators that automatically maintained a stable operating speed.
The next major advance was the emergence of practical non-condensing motors. However, Watt failed to perfect these types of machines.
What is the Papin machine?
Papin's machine is an improved version of the first steam engines.
Subsequently, the boiler was subjected to a cold source. In this way, the steam condensed and the piston lowered.
Papin invented and first used a safety valve in the design of a steam boiler.