How does a steam engine work? When it was invented?
Steam engines played a fundamental role in shaping the modern world. They were the first type of widely used engine. Thomas Newcomen invented them in 1705 and significantly improved them in 1769 with the help of James Watt (whom we think of every time we talk about the “60-watt lightbulb”). Marine Steam engines powered all locomotives, ships, and primitive factories, thus laying the foundation for the Industrial Revolution.
History of the Steam Engine
Steam technology dates back to around 75 A.D. C, when the famous mathematician Hero wrote extensively about the mechanics and properties of air and proposed a design for a primitive steam engine. Its design consisted of a hollow sphere with curved tubes sticking out of the sides. When the ball was filled with water and placed on a fire, the water evaporated due to the heat; the resulting steam leaked through the pipes, causing the ball to rotate. This invention laid the foundation for future developments in steam technology, but it was the contributions of many others that made steam power possible.
In the 17th century, Italian scholar Giovanni Battista della Porta noted the role of steam in creating a vacuum. He hypothesized that when water turned to steam inside a closed container, pressure would increase, and when the steam condensed back into water, pressure would decrease.
In 1679, French scientist Denis Papin turned della Porta’s theory into reality with a project: a pressure cooker-like device called a “bone tenderizer.” A closed container became the first practical application of steam pressure. Papin perfected the concept by using a piston to slide over a closed cylinder filled with water. As the water heated up, the steam expanded and pushed the piston upward. As it cooled and condensed, the resulting vacuum pushed the piston downward.
These early experiments and innovations marked important milestones on the road to harnessing steam power. They paved the way for future inventors and engineers to refine and expand on these concepts.
When was the Steam Engine Invented?
In 1698, military engineer Thomas Savery patented his innovative steam pump, known as the “Miner’s Friend.” Savery’s steam pump consisted of a boiling chamber that directed steam to a separate container. Inside the container was a tube with a check valve extending to the water that needed to be extracted. Cold water was poured over the steam-filled container, causing it to condense back into a liquid state. During this transformation, a vacuum drew the water from the bottom through the tube.
English inventor Thomas Newcomen was one of the pioneers in the development of steam power, with Savery’s separation of the boiler from the steam cylinder and Papin’s invention of a steam-driven piston. The air engine was invented in the early eighteenth century. This practical steam engine pumped water from a mine and used steam to create a partial vacuum in the cylinder, which created atmospheric pressure to push the piston downward.
James Watt improved the design and efficiency of the steam engine. In the late 18th century, he invented the Watt atmospheric engine, which had a separate condenser and was able to harness the expansion force of steam. The efficiency of the steam engine made it ideal for transportation, helping to connect distant regions and facilitate the transport of goods.
The advent of steam power and its subsequent development promoted industrialization and changed society. Steam power became the engine of the Industrial Revolution.
Operations of the Steam Engine
The engine shown is a double-acting steam engine, in which valves allow high-pressure steam to act alternately on both sides of the piston. The animation below shows the machine in action.
As you can see, the slide valve is responsible for letting high-pressure steam into both sides of the cylinder. The valve control rod is usually connected to a coupling mounted on a crosshead so that movement of the crosshead also moves the valve. In steam locomotives, this connection also allows the driver to reverse. This fact explains two things about steam locomotives:
- They fill the station with water, since water is constantly lost through the steam.
- Where does the “choo choo” sound come from? When the valve opens, the cylinder releases the steam, the steam escapes under tremendous pressure, and makes a “whoosh!” sound.
- When the train starts moving, the piston moves very slowly, but as the train starts rolling, the piston starts moving faster. The effect is the “choo…choo…choo…choo-choo-choo” we hear when starting.
- In a steam locomotive, the crosshead is usually connected to a connecting rod, and from there, it is connected to a connecting rod that drives the wheels of the locomotive. The crosshead is connected to a connecting rod, which in turn is connected to one of the three driving wheels of the train. The three wheels are connected by connecting rods so that they can rotate in perfect harmony.
Stationary Steam Engine
A stationary steam engine is a machine that is not designed to move. Unlike steam engines used in locomotives or ships, stationary steam engines are fixed in place and power factories, mills, pumping stations, or generators. They usually consist of a large steam boiler, a reciprocating or rotary steam engine, and various auxiliary components used to control and regulate the flow of steam and power output.
5 Types of Steam Engines
Throughout history, we have seen different types of steam engines. Here are some notable examples:
Reciprocating Steam Engine: This common steam engine is characterized by the reciprocating motion of the piston. Reciprocating steam engines use steam pressure to move the piston back and forth in the cylinder, converting linear motion into rotary motion.
Vertical Steam Engine: In a vertical steam engine, the cylinder is in a vertical position and the piston moves up and down.
Horizontal Steam Engine: This type of engine has a horizontally placed cylinder. Here, the piston moves back and forth.
Single-Flow Steam Engine: These engines are characterized by the flow of steam through the cylinder in only one direction.
Condensing Steam Engine: This type uses a separate condenser to increase efficiency. After the steam works in the cylinder, it condenses back into water, creating a vacuum, which increases the machine’s power and efficiency.
Boiler
The high-pressure steam needed for a steam engine comes from a boiler. The boiler’s job is to apply heat to water to create steam. There are two ways: fire tubes and water tubes.
Fire tube boilers were more common in the 19th century. They consist of a water tank covered with pipes. Hot gases from a coal or wood fire pass through the pipes to heat the water in the tank.
In a fire tube boiler, the entire tank is under pressure, so if the tank ruptures, there will be a huge explosion.
Today, water tube boilers are becoming more common, where water circulates through a network of pipes placed in the hot gases of the furnace.
In a real boiler, the situation is more complicated because the goal is to extract as much heat as possible from the burning fuel to improve efficiency.
