Thomas Savery - Invented the Steam Engine

Thomas Savery was born to a well-known family in Shilston, England sometime around 1650. He was well educated and exhibited a great fondness for mechanics, mathematics, experimentation and invention.

Savery's Early Inventions 

One of Savery's earliest inventions was a clock which remains in his family to this day and is considered an ingenious piece of mechanism. He went on to invent and patented arrangement of paddle wheels driven by capstans to propel vessels in calm weather.

He pitched the idea to the British Admiralty and the Wavy Board but met with no success. The principal objector was the surveyor of the Navy who dismissed Savery with the remark, "And have interloping people, that have no concern with us, pretend to contrive or invent things for us?"

Savery was not deterred -- he fitted his apparatus to a small vessel and exhibited its operation on the Thames, although the invention was never introduced by the Navy.

The First Steam Engine

Savery invented the steam engine sometime after the debut of his paddle wheels, an idea first conceived by Edward Somerset, Marquis of Worcester, as well as a few other earlier inventors. It’s been rumored that Savery read Somerset’s book first describing the invention and subsequently attempted to destroy all evidence of it in anticipation of his own invention. He allegedly bought up all copies he could find and burned them.

 

Although the story isn’t particularly credible, a comparison of the drawings of the two engines -- Slavery's and Somerset's -- shows a striking resemblance. If nothing else, Savery should be given credit for the successful introduction of this "semi-omnipotent" and "water-commanding" engine. He patented the design of his first engine on July 2, 1698.

A working model was submitted to the Royal Society of London.

The Road to the Patent

Savery faced constant and embarrassing expense in the construction of his first steam engine. He had to keep the British mines -- and particularly the deep pits of Cornwall -- free from water. He finally completed the project and conducted some successful experiments with it, exhibiting a model of his "fire engine" before King William III and his court at Hampton Court in 1698. Savery then obtained his patent without delay.

The title of the patent reads:

"A grant to Thomas Savery of the sole exercise of a new invention by him invented, for raising of water, and occasioning motion to all sorts of mill works, by the important force of fire, which will be of great use for draining mines, serving towns with water, and for the working of all sorts of mills, when they have not the benefit of water nor constant winds; to hold for 14 years; with usual clauses."

Introducing His Invention to the World

Savery next went about letting the world know about his invention. He began a systematic and successful advertising campaign, missing no opportunity to make his plans not merely known but well understood. He obtained permission to appear with his model fire engine and to explain its operation at a meeting of the Royal Society.

 The minutes of that meeting read:

"Mr. Savery entertained the Society with showing his engine to raise water by the force of fire. He was thanked for showing the experiment, which succeeded according to expectation, and was approved of." 

Hoping to introduce his fire engine to the mining districts of Cornwall as a pumping engine, Savery wrote a prospectus for general circulation, "The Miner's Friend; or, A Description of an Engine to Raise Water by Fire.” In part, the pamphlet read: 

“Then I (Thomas Savery) say, such an engine may be made large enough to do the work required in employing eight, 10, 15 or 20 horses to be constantly maintained and kept for doing such a work; it will be improper to stint or confine its uses and operation in reflect of water-mills.

It may be of great use for palaces, for the nobilities or gentlemen’s houses: For by a cistern on the top of a house, you may with a great deal of ease and little charge, throw what quantity of water you have occasion for to the top of any house; which water in its fall, makes you what forts of fountains you please and supply any room in the house. And it is of excellent use in cafe of fire, of which more hereafter.

Nothing can be more fit for serving cities, and towns with water, except a crank-work by the force of a river. In the composing such sort of engines, I think no person hath excelled the Mr. George Sorocold. But where they are forced to use horses, or any other strength, I believe no ingenious person will deny this engine to have the preference in all respects, being of more universal use than any yet discovered or invented.

As for draining fens and marshes. I suppose I need say no more than this, that the force which will raise great quantities of water a height of above 80 foot, must necessarily deliver a much greater quantity at a lesser height. And that it is much cheaper, and every way easier, especially where coals are water borne, to continue the discharge of any quantities of water by our engine, than it can be done by any horse engines what so ever.

I believe it may be made very useful to ships, but I dare not meddle with that matter; and leave it to the judgment of those who are the best judges of maritime affairs.

For draining of mines and coal pits, the use of the engine will sufficiently recommend it self, in raising water so easier and cheap; and I do not doubt, but that in a few year, it will be a means of making our mining trade, which is no small part of the wealth of this kingdom, double, if not triple to what it now is. And if such vast quantities of lead, tin, and coals are now yearly exported, under the difficulties of such an immense charge and pains as the miners are now at to discharge their water, how much more may be hereafter exported, when the charge will be very much lessened by the use of this engine, every way fitted for the use of mines? For the far greater part of our richest mines and coal-pits, are liable to two grand inconveniences, and thereby rendered useless; the eruption and excels of subterraneous waters, as not being worth the expense of draining them by the great charge of horses or hand labor. Or secondly, fatal damps, by which many are struck blind, lame, or dead in these subterraneous cavities, if the mine is wanting of a due circulation of air. Now both these inconveniences are naturally remedied by the work of this engine of raising water by the impellent force of fire.”

Implementation of the Steam Engine

Savery's prospectus was printed in London in 1702. He proceeded to distribute it among the proprietors and managers of mines, who were finding at that time that the flow of water at certain depths was so great as to prevent operation. In many cases, the cost of drainage left no satisfactory margin of profit. Unfortunately, although Savery's fire engine began to be used for supplying water to towns, large estates, country houses and other private establishments, it did not come into general use among the mines. The risk for explosion of the boilers or receivers was too great. 

There were other difficulties in the application of the Savery engine to many kinds of work, but this was the most serious. In fact, explosions did occur with fatal results.

When used in mines, the engines were necessarily placed within 30 feet or less of the lowest level and could potentially become submerged if the water should rise above that level. In many cases this would result in the loss of the engine. The mine would remain "drowned" unless another engine should be procured to pump it out.

The consumption of fuel with these engines was very great as well. The steam could not be generated economically because the boilers used were simple forms and presented too little heating surface to secure a complete transfer of heat from the gases of combustion to the water within the boiler. This waste in the generation of steam was followed by still more serious waste in its application. Without expansion to the expulsion of water from a metallic receiver, the cold and wet sides absorbed heat with the greatest avidity. The great mass of the liquid was not heated by the steam and was expelled at the temperature at which it was raised from below.

Savery quaintly relates the action of his machine in The Miner's Friend:

“The steam acts upon the surface of the water in the receiver, which surface only being heated by the steam, it does not condense, but the steam gravitates or presses with an elastic quality like air and still increasing its elasticity or spring until it counterpoises, or rather exceeds, the weight of the column of water in the force pipe. It will then necessarily drive up that pipe. The steam then takes some time to recover its power, but it will at last discharge the water out at the top of the pipe You may see on the outside of the receiver how the water goes out, as well as if it were transparent, for so far as the steam is contained within the vessel, it is dry without and so hot as scarcely to endure the least touch of the hand. But so far as the water is inside the vessel, it will be cold and wet on the outside, where any water has fallen on it; which cold and moisture vanish as fast as the steam takes the place of the water in its descent."

Improvements to the Steam Engine

Savery later began work with Thomas Newcomen on an atmospheric steam engine. Newcomen was an English blacksmith who invented this improvement over Slavery's previous design.

The Newcomen steam engine used the force of atmospheric pressure. His engine pumped steam into a cylinder. The steam was then condensed by cold water which created a vacuum on the inside of the cylinder. The resulting atmospheric pressure operated a piston, creating downward strokes. Unlike the engine Thomas Savery had patented in 1698, the intensity of pressure in Newcomen’s engine was not limited by the pressure of the steam. Together with John Calley, Newcomen built his first engine in 1712 atop a water-filled mineshaft and used it to pump water out of the mine. The Newcomen engine was the predecessor to the Watt engine and it was one of the most interesting pieces of technology developed during the 1700's.

James Watt was an inventor and mechanical engineer born in Greenock, Scotland, renowned for his improvements of the steam engine. While working for the University of Glasgow in 1765, Watt was assigned the task of repairing a Newcomen engine, which was considered inefficient but still the best steam engine of its time. He began to work on several improvements to Newcomen's design. Most notable was his 1769 patent for a separate condenser connected to a cylinder by a valve. Unlike Newcomen's engine, Watt's design had a condenser that could be kept cool while the cylinder was hot. Watt's engine soon became the dominant design for all modern steam engines and helped bring about the Industrial Revolution. A unit of power called the watt was named after him.

Parts extracted from: A History of the Growth of the Steam Engine, Robert H. Thurston, 1878