Watt Steam Engines

James Watt

The engine of Newcomen was very wasteful of coal even if there have been many improvements to the engine. James Watt was a man who wanted to know the exactness of things. He studied the Newcomen engine very precise and was astonished on how there was a need of water to be injected to cool down the steam. He recognized that there was a relevant loss of power. Watt made many studies concerning steam pressure, which he used for his great cognition. He recognized that it was useles to cool down the same vessel and heat it again. In his patent, he formulated among other things two principles:

1.Thermal insulation
The vessel, which worked by means of steam, had to be as hot as the steam itself.

2.Separate condenser
The vessel where the steam is condensed has to be separated from the cylinder and it has to be as cold as the outside temperature. Watt called it the "condenser."

Watt united these two principles in his first steam engine.

Watt's First Steam Engine (1776)

Watts first steam engine was (like the Newcomen-Engine) working at low pressure. The power could of course be enlarged by increasing the steam pressure, but it could also simply be enlarged by building greater cylinders. The advantage was that there was no need to work with high pressure. Therefore, not many detonations of the boiler ocurred.

One of the main problems Watt had was not technical related but of financial crisis. So the partnership with Matthew Boulton was very good for him; it made the base of all the inventions James Watt made.


Natural Expansion of The Steam

Watt discovered that there was no need to conduct steam during all the time the piston moved up. The natural expansion of steam can be used. The quantity of steam can be reduced to a fourth. Therefore, the piston did not press with the same force all the time, but Watt found out that this problem could be fixed with a fly-wheel.
Watt's second patent described among other things how the natural expansion of steam could be used. He described six ways of providing a regular running of the engine. He also described the double-acting engine in this patent and all the technical details which are necessary to provide a regular running of it. After a while there was also the idea of converting the up and down-movement of the piston into a rotating movement. Unfortunately, there was a patent of a man on this convertion. Watt and Boulton could go round it by inventing some new drivings. The invented i.e. the so called sun-driving.

James Watt also invented some new technical features of regulating the running of the engine. One of the most important inventions was the fly ball governor, which automatically regulated the conveying of steam.

Newcomen Steam Engines

Thomas Newcomen

When Thomas Newcomen began his first experiments in 1705, many people advised him to do otherwise. He was a simple smith and iron trader. Newcomen consistently thought about Papin's idea of an engine with a free piston. Although many people were dubious and considered it to be impossible to design a piston with a sufficient sealing, he began his work and in 1712 he presented his first engine, which immediately began its work in a mine .



An important advantage of Newcomen's engine compared to Savery's engine is that its power did not depend on the steam pressure but on the quantity of the cylinder. Because of this it was called low pressure steam engine.
Althought the engine needed an enormous amount of coal to work there were some attemps to improve the atmospheric engine. One of the first improvements was the invention of the injection condensation. In this case, the cooling water did not flow over the cylinder, but it was injected directly into the cylinder. The effect was a much faster condensation. Another improvement was the introduction of an automatic control. However, the efficiency was still very low. Much coal was used for just poor power.

John Smeaton

John Smeaton was one of the best engineers of his time. He began to optimize Newcomen's engine. He studied, first of all, every detail of the engine and made some experiments with this. Smeaton came to the conclusion that the engine lost much energy because of bad cylinders with unsufficient sealing. In addition, the measures of the parts did not match with each other, for example, the boiler was often too small compared with the cylinder to produce enough steam. He could design engines that worked very well because of better sealings and better measures of the parts.

Savery Steam Engines

Thomas Savery

By the end of the 17th century, the mine companies strongly needed new powerful pumps to extract water out of the mines. Many engineers managed to persuade prosperous company owners in favor of their projects, which were often unrealistic and unrealizable. The distrust in such engineers grew, and in 1702 Thomas Savery had serious problems when he published a script in which he described the advantages and the mode of operation of an engine that would transport water out of mines easier. He called his script The Miners Friend. His goal was not to make unrealistic promises. He wanted to explicate to people how his engine worked. Society would then decide whether or not his engine is worth building.

Papin's Steam Engines

Denis Papin

Denis Papin was an assistant of Huygens. Huygens showed him the gunpowder-engine. The power of this engine was not effective. Papin could at least make the operation of the engine more secure with his invention of a touch-pan. However, the engine firing off was still very dangerous because its material could hardly stand the huge explosions. Papin then thought of his knowledge of water. He knew that water can get "as elastic as air" and also knew that this procedure could be reversed. Therefore, he wanted to create an engine that could produce the "entire emptiness".

Papins atmospheric piston engine



The cylinder was filled up halfway with water before the piston is pushed down to the water. The air can escape through a small tube. If the whole cylinder is heated, the water converts into steam; the steam presses the piston up. In the highest position, a fastener grabs the piston and holds it at the head. When the steam condenses, the atmospheric pressure will press the piston back down. The power stroke does not occur during the vaporizing but during the condensation of steam. Papin intended to lift a weight with a cord over a spool. He calculated that an engine with a piston of 24 inches in diameter and a stroke of 4 feet could lift a weight of 3.5 tons. This would be equal to 1 Horsepower.

His engine was not at all satisfying. The power was limited, because all functions have been inside of one tool (boiler, cylinder, piston)that had to be heated and cooled. Furthermore, the engine was only cooled with fresh air. Papin also invented a geared piston bar, which could turn a cogwheel while the piston slided downward during the work period of the engine. But he could not manage the construction because of his insufficient technical knowledge. There was no hand worker that could produce an example of the engine and his own knowledge was only sufficient for his labour. Papin was more successful in inventing other different things besides steam power.

Some years later, Papin received an order from the count of Kassel. He was asked to build an engine that could lift water to a defined height. The count paid all the covers. Papin developed in his engine some interesting technical details. He used a free-swimming piston which prevented the steam from condensing on the cold water-surface. Furthermore, he invented a safety valve that limited the maximal steam-pressure. Unfortunately, the joints and valves were leaking so the count lost the interest in Papins steam engine and researches.