The world's first steam engine was the Aeolipile invented by the ancient Greek mathematician Hero of Alexandria in the 1st century. This was the prototype of the steam engine.
About 1679 French physicist Denis Papen built a working model of the first steam engine after observing steam escaping his pressure cooker. About the same time Samuel Moran also came up with the idea of ??a steam engine.
Thomas Seville in 1698, Thomas Newcomen in 1712 and James Watt in 1769 built early industrial steam engines. They all made their own contributions to the development of steam engines. In 1807 Robert Fulton was the first to successfully use a steam engine to drive a ship. Watt used scientific theories to gradually discover the problems with this steam engine. From 1765 to 1790, he made a series of inventions, such as the separate condenser, the insulation layer outside the cylinder, the piston lubricated with oil, the planetary gear, the parallel motion linkage mechanism, the centrifugal governor, the throttle valve, Pressure gauges, etc., increased the efficiency of the steam engine to more than three times that of the original Newcomen engine, and finally invented the steam engine in the modern sense.
From the end of the 16th century to the late 17th century, the British mining industry, especially coal mines, had developed to a considerable scale. Manpower and animal power alone could no longer meet the requirements for removing underground water from mines, and there were abundant and abundant underground water on site. Cheap coal as fuel. Realistic needs have prompted many people, such as Papin, Savery, and Newcomen in the UK, to devote themselves to the exploration and experiment of "lifting water with firepower".
The original vacuum steam engines were used to pump water out of mines. Newcomen's steam engine introduced steam into a cylinder and the valves were closed. Cold water was then poured into the cylinder, creating a vacuum as the steam condensed. Air pressure on the other side of the piston pushes the piston. In a mine, a rod is connected deep into the shaft to drive a pump. The motion of the steam engine's piston is transmitted through this rod to the pump's piston to draw water out of the well.
The first huge improvement was to separate the cylinder from the condensation cylinder by a valve. Watt invented this improvement in Birmingham. This improvement increased the efficiency of the steam engine. The next improvement was to automate the operation of the valve.
These early vacuum steam engines had limited efficiency, but they were safer because their pressure was lower and the machines contracted inward rather than exploding outward in the event of material damage. Their efficiency is limited by external air pressure, cylinder deformation, efficiency of combustion and boiling, and condensation capacity. The theoretical maximum efficiency is limited by the relatively low boiling temperature of water at ordinary atmospheric pressure. The use of high-temperature and high-pressure steam greatly improves the efficiency of steam engines. But this type of steam engine is much more dangerous than a vacuum steam engine. Explosions of boilers and machinery caused many major accidents. The safety valve brings a big improvement here, and the safety valve relieves the pressure when the pressure is too high. But the real guarantee of safety can only rely on experience and safety rules in construction, operation and maintenance.
The world's first practical steam water lifter made by Savery was awarded a British patent titled "Miner's Friend" in 1698. He first filled an egg-shaped container with steam, then closed the steam inlet valve and sprayed cold water outside the container to condense the steam inside the container to form a vacuum. Open the water inlet valve, and the water at the bottom of the mine will be sucked into the container through the water inlet pipe under the action of atmospheric pressure; close the water inlet valve, reopen the steam inlet valve, and rely on steam pressure to force the water in the container out through the drainage valve. When the water in the container is drained and filled with steam, close the steam inlet valve and drain valve, and spray water again to condense the steam. Repeat this cycle and use two egg-shaped containers to work alternately to achieve continuous drainage.
Savery’s water lift relies on vacuum suction to draw water to a depth of no more than six meters. In order to draw water from a mine that is tens of meters deep, a water lift must be installed deep in the mine, and high steam pressure can be used to press the water to the surface. This was undoubtedly difficult and dangerous at the time.
Newcomen and his assistant Calley invented the atmospheric steam engine in 1705 to drive an independent water pump, which was called the Newcomen atmospheric steam engine.
This steam engine was rapidly promoted first in Britain and later in continental Europe, and its modified products were still manufactured until the early 19th century. The thermal efficiency of the Newcomen atmospheric steam engine is very low. This is mainly because when the steam enters the cylinder, it condenses on the cylinder wall that has just been cooled by water and loses a lot of heat. It is only popularized in coal-producing areas with low coal prices.
In 1764, the British instrument repairman James Watt noticed this shortcoming when he was repairing the Newcomen steam engine model for the University of Glasgow, and in 1765 he invented a condenser separated from the cylinder wall. steam engine and obtained a British patent in 1769. The early Watt steam engine still used a balance lever and a tie rod mechanism to drive the water lift pump. In order to remove the condensed water and air from the condenser, Watt installed an air extraction pump. He also installed an interlayer on the outer wall of the cylinder and used steam to heat the cylinder wall to reduce condensation losses.
Watt's creative work led to the rapid development of the steam engine. He turned the original machine that could only lift water into a steam engine that could be widely used. He doubled the thermal efficiency of the steam engine and greatly reduced the coal consumption. Therefore Watt was an improver of the steam engine.
Since the late 18th century, steam engines have been widely used not only in the mining industry, but also in smelting, textiles, machine manufacturing and other industries. It increased British textile production five times in more than 20 years (from 1766 to 1789), provided the market with a large number of consumer goods, accelerated the accumulation of funds, and put forward urgent requirements for the transportation industry. Billy sucks
The experiment of using steam engines as propulsion power on ships began in 1776. After continuous improvement, by 1807, Fulton of the United States made the first practical paddle-wheel propelled steam engine. Ship "Clermont". Since then, steam engines have been used as propulsion power on ships for more than a hundred years.
In 1800, Trevithick of England designed a high-pressure steam engine that could be installed on a larger car body. In 1803, he used it to propel a locomotive running on a circular track, and he invited people who liked novelties to ride on them and charged them a fee. This was the prototype of the locomotive. The British Stephenson continuously improved the locomotive and created the "Rocket" steam locomotive in 1829. The locomotive towed a carriage carrying 30 passengers at a speed of 46 kilometers per hour. It attracted the attention of various countries and pioneered the railway industry. era.
At the end of the 19th century, with the rise of electricity applications, steam engines were once used as the main power machinery in power stations. In 1900, there was a steam power station in New York, USA, with a single power of five megawatts.
The development of steam engines reached its peak in the early 20th century. It has the advantages of constant torque, variable speed, reversibility, reliable operation, easy manufacturing and maintenance, etc. Therefore, it has been widely used in various fields such as power stations, factories, locomotives, and ships. Especially on warships, it became the only prime mover at that time. .
It is important to note that many textbooks (history books, physics books) say that Watt was the inventor of the steam engine. This is misinformation. The steam engine was independently invented by the British Savery in 1698 and Newcomen in 1705, and was used to pump water in mines. It was very inefficient at the time.
In 1765, Watt made major improvements to the steam engine based on repairing the Newcomen engine, separating the condenser from the cylinder, inventing the crankshaft, gear transmission and centrifugal governor, etc., making the steam engine realize Modernization greatly improved the efficiency of steam engines. These inventions of Watt are still used in modern steam engines. To commemorate Watt's contribution, the name of the unit of power is named after his surname. ("Physics (Fifth Edition)") Overview
In terms of land transportation, people began to develop a means of transportation that could use steam engines to propel vehicles forward quickly. Among them, the British George Stephenson (1781-1848) was the first to achieve breakthrough results.
Stephenson was the son of a coal miner. He was familiar with the steam engines used to pump water in the mines since he was a child, and later determined to engage in the invention and creation of transportation vehicles.
In 1814, the first steam locomotive he developed, the "Bratzer" (named after the Prussian general Bratzer, who helped the British fight against Napoleon's army), had a successful trial run.
On September 27, 1825, Stephenson personally drove the "Traveler" steam locomotive he designed and manufactured in collaboration with others to test run on the newly laid railway, and achieved success. The application of steam engines in the transportation industry brought mankind into the "train age" and rapidly expanded the scope of human activities.
Stephenson’s history of the development of steam locomotives
When Stephenson trial-operated the "Bratzer" locomotive in 1814, although it was successful, it also exposed many problems, such as The noise is too great, the vibration is strong, and the steam engine may explode at any time. When the train started moving, thick smoke billowed out, and sparks flew out when the wheels rubbed against the rails; the people sitting on the train had their faces covered with smoke and dust, and were exhausted from the jolt. The flames from the steam engine scorched the nearby trees. This may be why people called it a "train" at the time.
However, Stephenson was not discouraged and continued to improve. He installed shock-absorbing springs under the carriages, used wrought iron instead of pig iron as the track material, added pebbles under the sleepers, increased the number of wheels on the front of the car and the carriage, and installed a steam engine on the front of the car to reduce the risk of damage in the event of danger. Damage etc.
By the time Stephenson trial-operated the "Traveler" locomotive in 1825, the situation had improved considerably. The "Voyager" towed 6 coal cars and 20 carriages packed with passengers, with a load of 90 tons and a speed of 15 miles per hour. This spectacular scene attracted many people to watch. There were crowds of people on both sides of the railway; there were also people riding horses and walking in front of the train with red flags to clear the way. With the sound of a train, it announced to the world the arrival of the railway age.
In 1829, Stephenson successfully trial-produced a more advanced "Rocket" locomotive.
(The above content on Stephenson and Steam Locomotives comes from Beijing Normal University’s history textbook)