steamengine

THE EARLY DEVLOPMENT OF THE STEAM ENGINE DAVID K HULSE. Retired Chief Development Engineer Royal Doulton. SYNOPSIS In 1976, after years of restoring and riding motorcycles, I decided that I would research and construct in miniature, what I considered to be the most important steam engines, (atmospheric engines) which were built between the years 1712-1804. These historical engines, really paved the way, for the advancing industrial revolution in the British Isles and in many countries throughout the world. In chronological order, these engines are: One) Thomas Newcomen’s Dudley Castle Engine, is the world’s first recorded steam engine which was built in 1712 to draw water from a coal mine at Tipton in South Staffordshire. The only pictorial record of this engine was drawn in 1719 by a Wolverhampton file maker called Thomas Barney. However, this drawing was only rediscovered in 1868 in a collection of documents which had been amassed by William Salt a merchant banker. This original drawing is now in the William Salt Library in Stafford. A reproduction from this drawing is shown as Figure 1. Two) James Watt’s - The Smethwick Engine, one of the first engines to be designed by James Watt which was used to pump water up a series of canal locks. This is the first of Watt’s three valve engines. This design of an engine was so successful that the seventy-five Newcomen engines which were working in the Cornish Mineral mines in 1779 had, all been superceded within four years. A Watt engine of the same size as a Newcomen engine developed twice the power for the same consumption of coal. The Smethwick engine went into service in May 1779. Three) Is an engine designed by Matthew Wasborough a Bristol engineer for James Pickard a Birmingham manufacturer. This was to become the first engine in the world to successfully achieve rotary motion, by the use of a crank and flywheel. A patent was taken out for this mechanism on the 23rd August 1780. The granting of this patent is the reason why James Watt used the sun and planet on his engines to achieve rotary motion without any infringement of the Pickard patent. Four) A second engine by James Watt - this engine was specifically designed to provide rotary motion, and has become known as the Lap Engine, because of its task of driving machinery which was used in the lapping and polishing of small manufactured articles. The Lap Engine was made in 1788 and, is to be the principal subject of this paper. Page 1 of 22 Five) A beam engine designed to provide the rotary drive for a worsted mill at Arnold Nottingham. This engine was designed by an engineer from Ashover in Derbyshire, called Francis Thompson. He took out a patent for this unique engine in 1792. The engine’s unusual features were designed, to achieve success, without infringing a patent taken out in 1769 by James Watt on steam engine design. This patent by Watt ran for a total of 31 years. The engine at Arnold was built in 1797 and only worked until 1808. In 1811 the Mill was demolished and the engine was sold for scrap. Six) This is an engine designed by Richard Trevithick the Cornish engineer and, was built in 1804 to provide the rotary power to drive a dye house at Lambeth in London and, is the first design of an engine to work with steam raised to a high pressure. A drawing in John Farey’s book a Treatise on the Steam Engine Volume 2 is the only known record of this engine. This book was written in the early 1 9th century and published for the first time in 1970. The cylinder of this engine was positioned horizontally. The engine produced six horsepower and revolved at 26 RPM. This was a high speed in 1804 and, became known as a compact high speed engine. Seven) This is a miniature of a high pressure beam engine built c1860. This miniature does not represent any particular evolutionary step; I generally refer to this engine as my apprentice piece. However, it does show how engine power increased and the engine’s physical size decreased. The seven miniatures briefly described here have taken more than twenty-three years to complete, and over this time some 23,000 hours have been spent on their construction. As well as the actual miniatures, some special tools and machinery had to be designed and made, because none of the items needed to construct these miniatures were commercially available. No parts of the models are made from materials which would have been available to the engineers of the eighteenth century. My everyday job before I retired was that of the Chief Development Engineer for Royal Doulton and, it was this discipline which enabled me to make all the items which are not generally used in miniature engine construction. I designed a special machine to make all the miniature bricks which were used for the buildings. Because in the eighteenth century steam engines were always a structural part of the actual building, in which they were used. All these engines can be seen by visiting www.btinternet.com/~historical.engines I travel widely giving lectures on the development of steam power during the eighteenth century and can be contacted on 01785 818773. Also two books have been published on my research into the engines of the eighteenth century which can be obtained from the author, details on the above web site, or from TEE Publishing at Leamington Spa. www.fotec.co.uk/mehs/tee DAVID K HULSE 30 December 2001 Page 2 of 22 THE WORLD’S FIRST COMMERCIAL STEAM ENGINE Figure 1 A print from Thomas Barney’s engraving of 1719, showing the world’s first commercial steam engine which was built in 1712 by Thomas Newcomen to draw water from a coal mine at Tipton in South Staffordshire. Page 3 of 22 SOHO MANUFACTORY Matthew Boulton and the Soho Manufactory Matthew Boulton was born at Snow Hill, Birmingham, on 3rd September 1728. His father was a small article manufacturer and the business was run from a factory adjoining their house. It is thought that his father specialised in the manufacture of buttons and buckles. These small article manufacturers, who made products from metal, were called ‘toy-makers’. At an early age, Matthew Boulton showed a keen interest in his father’s business. And on his father’s death the whole business was transferred to him. Under his management, the business grew and prospered. He was an ambitious man with a vision and he thought up a scheme to manufacture a large variety of hardware which was all to be contained on one single location. His present site became too small and, so that he could carry out his plans for this expansion, he searched for a larger site on which to expand. In 1761 he found such a site at ‘Soho’, only two miles from the original factory at Snow Hill. For this new venture it became essential to have a good water supply - and at this new site there was already a water-powered mill which had been used for the grinding of corn. After securing a lease Matthew Boulton became a partner with John Fothergill and each man invested £5,000 into this new venture. The Soho Manufactory as it became known was soon established, but the water powered mill proved unsatisfactory and was demolished. The factory when completed, was a three-storey building and was the first of its kind for the manufacture of hardware. It also had an adequate water supply which was used to drive the new machinery. Figure 2 shows an artistic impression of the Soho Manufactory drawn in 1798. Figure 2 The Soho Manufactory the first factory ever to be built for the manufacture of hardware The original Snow Hill premises were closed down and all the manufacturing of the hardware was transferred to this new factory at Handsworth. With the development of this ‘factory system’, the business flourished and within the first five years two extensions were added. The ‘Soho Manufactory’ and was run by Matthew Boulton in partnership with several men, notably Fothergill and Scale. Some of the items produced at the Soho Manufactory were toys, silver and plate ware, pictures and document copying, buttons and buckles, coins and medals. In 1779 Boulton produced copper coins for the British realm and they became known as the Boulton coinage. Page 4 of 22 BOULTON COINAGE This coinage was not favourably accepted by the public because it was too heavy for common usage, for example a two penny piece was made which actually weighed two ounces. However, the Lap Engine which is to be the subject of this paper drove the machines which made the copper blanks used in the production of these coins. A two penny piece is shown in Figure 3. Figure 3 Boulton Coinage these copper coins were produced in 1797 A most outstanding partnership was formed in 1775 when James Watt joined forces with Matthew Boulton to produce Watt’s improved steam engines. The water power at the Soho Manufactory became inadequate and a new source of power had to be found to drive the machinery at this factory. Matthew Boulton thought that James Watt’s engines would be suitable to provide this extra power as they were * single action pumping engines and they could be used to pump water into the tail-race ofthe water wheels, which would then provide this extra rotary motion to the process machines. Boulton and Watt’s engines were eventually used for the draining of mines in many parts of the country. The Cornish tin and copper mines were the most noted for their use of these pumping engines. In the early years of their partnership James Watt only designed the steam engines, the complete engines were never made at the Soho Manufactory, but the component parts were made by other manufacturers such as John Wilkinson, who made the cylinder and the main castings at his Bersham Ironworks. It was at the Soho Manufactory that the Lap Engine was assembled in 1788, the engine drove the lapping and polishing machinery until the factory ceased production in 1858. Before describing this engine in detail a short description of its predecessors is given, starting with the Newcomen engines which were installed in the Cornish mineral mines in the early 1 720s. * a piston powered in one direction Page 5 of 22 The engines designed by James Watt to provide rotary motion and, his invasion of Cornwall The first atmospheric pumping engine designed by Thomas Newcomen to draw water from a mineral mine in Cornwall was set to work at Wheal Fortune, a copper mine on the boundary of St. Hilary and Ludgvan parishes. This engine has been authenticated as working in 1720 and, this was then followed by an engine erected in 1725 at Wheal Rose near Chacewater. In the following two years, a further two engines were built one at Wheal Busy at Chacewater and the other at Polgooth, near to St. Austell. All of these engines were erected by Joseph Hornblower, a Staffordshire man who made Thomas Newcomen’s acquaintance during the pioneering days of the Newcomen engines. For the succeeding fifty-seven years, the Newcomen type of engine remained unchallenged for draining water from the coal and mineral mines, even though it had a prodigious appetite for consuming coal this had to be accepted if the vast mineral wealth below the natural drainage, or adit, was to be mined safely. As the mines became deeper in the never-ending search for minerals, the Newcomen engine was found to be not powerful enough to draw water from these greater depths. Seventy-five Newcomen engines have been authenticated as been erected in Cornwall by 1777, and it was in this year that James Watt and Matthew Boulton commissioned their first engine at a mineral mine in the west country. This Watt engine was assembled at Wheal Busy at Chacewater and, was a single-acting engine with a powering cylinder of 30 inches in diameter. Although the engine was still powered by atmospheric pressure, however, on this engine the vacuum which was applied to the underside of the piston was created by the condensation of steam inside James Watt’s patented water-cooled condenser. So successful was the Watt engine that by about 1783 only one Newcomen engine was said to be left in the whole of Cornwall and, even this lone survivor was not at work. The rapid demise of the Newcomen engine in Cornwall was due to the fact that the pumps driven by these engines had reached the greatest depths from which they could successfully draw the flood water from the mines, together with the nearest source of the coal for the furnaces being in South Wales. The Watt engine was the answer which all the mine captains had been waiting for it was far more powerful and it consumed much less coal. In other parts of the country, the early Newcomen engines were drawing water from coal mines where the cost of coal was not such an important factor and, coal mines were not usually as deep as the metalliferous mines in Cornwall. The last two Newcomen engines to be made were in 1797 and 1840, the engine made in 1797 was for the Elsecar Colliery near Barnsley and, this engine is now the only Newcomen engine still assembled in its original building in the world. The last engine was made by Joseph Thompson to draw water from a lead mine near to Bakewell in Derbyshire, this is known as the Magpie Mine. Boulton and Watt sold their engines under the terms of an annual payment to the Birmingham company, this was calculated at one-third of the cost of the coal savings, over that which would have been used, if a standard Newcomen engine had been installed to perform this drainage task. The reward to the patent holders and the economic value of the separate condenser to Cornwall was typified by the case of the Great Consols Mines in Gwennap, where seven Newcomen engines in 1778-79 consumed 19,086 tons of coal, whilst the five Boulton and Watt engines which had replaced them by 1783 consumed less than one-third of this, only 6,090 tons, during the same period. This amounted to a saving of £9,097 per annum for the mine owners, who agreed to pay Boulton and Watt an annual payment of £2,500 for these five engines. Page 6 of 22 DOUBLE ACTING CYLINDERS New Design of Powering Cylinder So successful was the separate condenser at reducing the amount of steam needed to operate these engines that the age of cylinders powered in both directions or double acting, was now dawning. This new design of an engine was needed to provide the rotary motion for industries which had previously been reliant on horse powered whims and flowing water, so the next engine in this series of early steam engines can now be considered, possibly the most famous engine of all the Boulton and Watt engines ever to be made, the Lap Engine of 1788. Figure 4 A double acting cylinder powered by both the expansive force of steam and a vacuum on each side of the piston. Page 7 of 22 THE LAP ENGINE With the introduction of the rotative engine, the Cornish mining industry was to have a further advance of Boulton and Watt engines, as the ore from the mine workings could be hauled safely to the surface by these new engines which replaced the horse whims previously used. H W Dickinson and R Jenkins record in their book, James Watt and the Steam Engine, that sixty-one Boulton and Watt engines had been erected in Cornwall between the years 1777 and 1800 and eight of these were beam engines, powered by double acting cylinders operated by a vacuum, a vacuum which had been first created within Watt’s separate condenser. The Lap Engine James Watt designed and built this beam engine in 1788 to directly produce rotary motion. The engine was powered by a vacuum and, also the expansive force of steam was used, the vacuum was created by the condensation of steam within Watt’s patented water-cooled condenser. The vacuum was first directed to the top, and then the underside, of the piston, low pressure steam was also applied to the piston and, was applied on both up and down strokes. This combination of a vacuum and low pressure steam produced a continuous output of energy which powered the engine. By 1788, many other beam engines had been adapted to provide rotary motion, but they had not been designed and built for this exclusive purpose and they were usually adaptations of single acting pumping engines. This rotative beam engine was erected at Boulton and Watt’s Soho Manufactory in Birmingham, where it became known as the Lap Engine because it was used to lap and polish small manufactured components such as the large buckles used on court shoes. The operators polishing these small items were generally referred to as ‘toy makers’. The Lap Engine continued to drive the factory machinery for seventy years until the Soho Manufactory ceased production in 1858. The engine is now on display at the Science Museum in London. The framework of the engine was built entirely from wood, all of which was held together by wrought-iron straps, and bolts. The engine had a double acting cylinder ofaimost 19 inches in diameter with a working stroke of 4 feet. The engine was the first in the world to have its rotational speed controlled by a centrifugal device which later became known as the’ Watt governor’ . Page 8 of 22 THE LAP ENGINE Figure 5 The Lap Engine as displayed in the Science Museum in London The large flywheel of this engine, with three hundred and four wooden teeth, drove more than forty lapping and polishing machines at the Soho Manufactory and the rotary power was transmitted to each individual machine by the means of belts and pulleys. The Lap Engine was one of the first rotary engines to have its power output rated in horsepower. This power was calculated by James Watt to be 10 normal horse power however, when the engine was in motion an indicated horse power of 14 was stated. When the Soho Manufactory ceased working in 1858, the engine was first put into storage, where it was to remain until 1861. Matthew Piers Robinson Boulton ( Matthew Boulton’s grandson) then presented the engine to the Patent Museum in London, where it was to remain on display until 1926. Unfortunately, the engine was not reassembled in the museum as it had originally been used at the Boulton and Watt Manufactory. Page 9 of 22 THE ENGINE IN MINIATURE The engine, with its large flywheel of almost 16 feet in diameter, was assembled like many later nineteenth-century engines with the lower half of the flywheel below the factory floor level. However, the engine erectors were unable to dig a pit for the flywheel, because, the engine was assembled on the first floor of the museum, the parts which would have been below the floor level were therefore put into storage. The engine was transferred in 1926 from the Patent Museum to the South Kensington Museum, but through the years some of the parts that had been placed in storage had become mislaid and the lower half of the sectional flywheel is now actually made from wood. At least the engine is complete again below the working floor level, even though the engine was still not assembled how it had been originally used at the Boulton and Watt Manufactory during its working life of seventy years. Only the engine is displayed in the Science Museum and, there are no remains of the original waggon boiler which supplied the steam to power this engine this fact was discovered from two drawings dated 29th July 1788 and fortunately these drawings show the Lap Engine residing in the same building side by side with the boiler - an unusual feature because at this date most engines and boilers were sited in separate buildings. A great effort has been made to create the model of the Lap Engine as it would have appeared in 1788. Wherever possible the miniature engine has been constructed from the same materials, which would have been used by the original engineers in 1788 and, the whole project has taken more than five years to complete. An Introduction to the Miniature Lap Engine The Lap Engine is displayed in the museum without its boiler or engine house, so some tentative inquiries were made to see if there were any detail drawings or artists’ impressions of the original engine which were available to the general public. The only information which was available to me at this stage was two arrangements drawings which had been produced in 1950 by the staff of the museum. However, these drawings did not have any dimensions which would be needed to make an accurate model. Neither was there any information on these drawings as to how the engine had been originally installed at the Soho Manufactory in Birmingham where it worked from 1788 until 1858. This made me realise that a great deal of research would be needed before a start could be made on my chosen subject. Two weeks later I returned to the Science Museum with my camera and a wooden rule and on this visit more than one hundred black and white photographs were taken of the engine. Page 10 of 22 THE ENGINE IN MINIATURE The wooden rule was placed on every component of the engine as each photograph was taken, so that I could determine the exact size of each part. Gleaming information in this way greatly reduced the amount of detail drawings needed for the actual construction of the miniature engine, but I still required many more visits to the Science Museum to check on dimensions and, of course, to obtain more details. By November 1980, the model had been completed and I was very pleased to exhibit it at the Midlands Model Engineering Exhibition organised by TEE Publishing at the Bingley Hall in Birmingham where I received first prize and the Modelcraft Cup. In January 19801 exhibited the one sixteenth scale model at the Model Engineering Exhibition held annually at Olympia and again I was very lucky to win first prize and the Championship Cup. However, my triumph was short-lived, because in the March edition of the Model Engineer it was pointed out to me that I had made several construction errors. After this report, Professor D H Chaddock wrote to me and suggested that I should contact Mr Michael Wright at the Science Museum who had found two original drawings dated 29th July 1788. These drawings clearly show a waggon boiler was originally used to power this engine and not the haystack boiler that I had made and fitted to my model. With these drawings, my errors could now be corrected and I set to work and completely dismantled the model to rebuild all the component parts of the model of the engine into a sectional arrangement of the original building. Nine months later, the model reemerged as an exact miniature of the Boulton and Watt Lap Engine as it had been built originally at the Soho Manufactory in Birmingham. Now that I have introduced the model of Boulton and Watt’s Lap Engine, I will describe the evolution of the engine, and how it was made by James Watt in 1788. All the materials used in the engine in miniature were the same as those which would have been used on the original full size engine when it was first built my James Watt in 1788. More than 11,000 ceramic bricks were produced for the engine-house. The bricks were made by hand and were fired in a homemade kiln which gave the one sixteenth full size miniatures the appearance of having been made two hundred years ago. The building foundation was made from 1,500 hand-cut sandstone blocks. Counting all the bricks, nuts, pins, washers and hand forged panel pins, more than 36,000 separate parts have individually been made. The toothed flywheel was the most time-consuming single item to be made, being made from 509 separate parts. Page 11 of 22 THE LAP ENGINE AS IT WAS USED IN 1788 Figure 6 The Lap Engine as it was assembled at the Soho Manuf~ctory in 1788 This layout was drawn by the author and, taken from the engine made in miniature. The Waggon Boiler. In his quest for higher efficiency, James Watt used a new type of boiler to power his improved beam engines. The design of a boiler used to power this engine was called a ‘waggon boiler’ because of its rounded top. This looked similar to the covered waggons used by travellers and gypsies from the sixteenth century onwards. l3efore the discovery of James Watt’s separate condenser which he patented in 1769, atmospheric engines were usually powered by haystack boilers, however, these boilers were inefficient when they were compared to the more modem waggon boilers. In some parts of the country, haystack boilers were also known as beehive boilers. Page 12 of 22 THE WAGGON BOILER The overall size of both waggon and haystack boilers was determined by the power output of the engine each cubic foot of operating cylinder volume had a known surface area which had to be exposed to the heating element, namely burning coal. The boiler which was used to raise the steam for the engine was of a very small size and volume, when compared to most later boilers designed by James Watt. Figure 7 The waggon boiler shown by the side of the engine, with a bone china model of James Watt made to the same scale as the model. Page 13 of 22 THE WAGGON BOILER This small size was achieved by using a central flue construction. The additional passage greatly increased the surface area which was exposed to the burning coal and hot exhaust gases, before these gases entered the chimney stack to atmosphere. A much simpler construction was used for subsequent boilers. The extra heating area was achieved by increasing the boiler’s overall size in order to obtain the required surface area without any need for the complicated central flue. Great difficulties were caused by the central flue boilers as the watertight joints were very difficult to produce in such a restricted space. The central flue boilers also proved very awkward for any routine maintenance such as descaling, which became a monthiy task. Many boilers powering engines after 1788 were of larger dimensions and were constructed without these central flues. Figure 8 Front view of the engine dated 29th July 1788 and signed by Matthew Boulton. Page 14 of 22 ORIGINAL INSTALLATION DRAWING Figure 9 A plan view of the engine showing the boiler by the side of the engine. Some of the contemporaly references show waggon boiler installations with their tops covered to conserve the heat. Inmost cases, this covering consisted of a 3 inch layer of horse or cow dung and a inch thick layer of lime mortar, all of this being covered by two layers of bricks. However, the Lap Engine’s installation drawing clearly shows the boiler top uncovered and, there is no indication of any lagging. The two drawings, Figs. 8 and 9, have been reproduced from the original sketches signed by Matthew Boulton and dated 29th July 1788. The waste gases flowed from the fire grate out to the atmosphere, the heat was drawn under the full length of the boiler shell. It was then diverted into two side flues which extended forwards to the fire door. The two flues then converged into one before the waste gases were finally drawn through the central flue into the chimney stack and, from where they then discharged out to the atmosphere. Page 15 of 22 BOILER DEVELOPMENT The Construction of the Boiler Shell The earliest boilers which were used to power the Watt engines were made of copper. This metal was chosen because it was malleable, so enabling the intricate shapes to be formed. Copper had been used for many years in the brewery trade for vessels and, so it could have been considered as a natural choice for steam engine boilers. However, the use of copper created problems, because it caused an accumulation of sediment inside the boiler which in turn formed hot spots which were liable to burn through the boiler’s shell. With the improvement in manufacturing techniques for boilers, the early 1 780s saw a change to wrought iron for their construction. However, in the early days of the Soho Manufactory, good wrought-iron plates were very difficult to produce. The method used was to forge wrought iron billets into the required flat sheets, success depended on the type of wrought-iron used. Insurmountable difficulties were found with the use of English wrought iron billets because of their brittle nature and a much greater success was assured by using wrought-iron which had been imported from Sweden or Russia. These two countries produced a very ductile iron which could be easily forged into the intricate shapes needed for boiler production. Because of this, in the early years of the 1780s ‘Russia slabs’, as they came to be known, were widely used - the Oxford English Dictionary states that ‘Russia Sheet Iron’ is a ductile sheet iron made in Russia and having a smooth glossy surface of purplish colour, sometimes mottled. It seems that the Lap Engine’s boiler plates were made to their final size and thickness at Burton-on-Trent in Staffordshire. The iron billets (see Burton upon Trent, The Development of Indusry by C. C. Owen) arrived from Sweden or Russia at the port of Hull, before being passed upstream to be processed in the Midlands. On arrival at Burton Wharf, the billets were collected on behalf of the Birmingham and South Staffordshire hardware manufacturers. One of these manufacturers, Nathaniel and Charles Lloyd, owned one of the Burton forges where the wrought iron was processed by hammering the billets into flat sheets using their water driven tilt hammers. Amongst their many customers, Charles Lloyd was proud to state that Burton Forge supplied Boulton and Watt of Birmingham with iron plates for boiler construction. This company produced many ofthe plates supplied to the Soho Manufactory from the mid-i 780s onwards. The Lap Engine boiler was small and, used plates of 1/4inch thick. These plates were then put together by using rivets 5/8 inch in diameter. Page 16 of 22 Watt’s Parallel Motion During his long working life, James Watt said that he gained the most satisfaction from his invention of converting a radial displacement into a rectilinear or straight line movement. This came to be known as Waif ’s parallel motion. He first thought of this theory in 1784 and in a letter to Matthew Boulton, written in the same year, he told him of this idea (Dickenson and Jenkins, James Watt and the Steam Engine): ‘I have started a new hare. I have got a glimpse of a method of causing a piston rod to move up and down perpendicularly by only fixing it to a piece of iron upon the beams without chains or perpendicular guides or untowardly frictions, arch-heads or other pieces of clumsiness; by which contrivance if it answers fully to expectation about five feet in the height of the engine house may be saved when assembling an engine with an eight foot stroke. Figure 10 The parallel motion arrangement which was fitted to the Lap Engine. Watt says is one of the most ingenious mechanisms he had contrived. Page 17 of 22 ROTARY MOTION WITHOUT INFRINGEMENT OF CRANK PATENT I have only tried it in a slight model yet so cannot build upon it, though I think it a very probable thing to succeed, and one of the most ingenious simple pieces of mechanism I have contrived.’ In order to try out this new idea, James Watt built a large-scale model which used his parallel motion design and this was so successful that he took out a patent for this mechanism on the 24th August 1784, in anticipation of putting it to use on a full size engine. To enable the power of a double acting cylinder to be successfully transmitted onto the main oscillating beam of an engine, the need for an efficient method of parallel movement was vitally important if the engine was to operate successfully, without applying any sideways forces onto the piston rod. Rotative Motion - The Sun and Planet Gears From the introduction in 1712 of Thomas Newcomen’s ‘fire engine’ (Atmospheric engine), philosophers tried unsuccessfully for almost seventy years to harness the power of its oscillating main beam to produce direct rotary motion. During this period, Neweomen’s pumping engines provided rotary motion to industries by pumping water into the tail-race of an overshot water wheel. However, this method of producing rotary motion was only economic, where the engine could be used both for the draining of mines and, the working of a water-wheel before the water eventually flowed away to waste. Any resulting rotary motion was an added bonus produced at a minimum cost! In the early days of the Soho Manufactory, rotary motion for the workshops was also produced by this very simple means. ‘Old Bess’, an early James Watt pumping engine, drew water from the factory’s mill pond to a waterwheel and after rotating the wheel the water was then lifted back to the mill pond. ‘Old Bess’ was in continuous use from about 1777 until 1848 and, this single action pumping is now preserved in the Science Museum at South Kensington. Trying to produce rotary motion directly from Newcomen type engines had become a baffling occupation for the early engineers - the operation of these engines left the developers or engineers at a complete loss. How do you fit a crank to an oscillating beam that does not move through the same angular movement from cycle to cycle? The Newcomen type engines had also a variable cycle time dependant on the amount of water which was being lifted on each stroke of the engine. However, these variations are not important in a simple pumping operation, but with a rotary engine all these differences had to be eliminated. The crank was the accepted method of producing rotary motion even in those early days cranks had been used for many years on treadle lathes they had even been fitted to waterwheels where linear motion was required. Page 18 of 22 ROTARY MOTION WITHOUT INFRINGEMENT OF CRANK PATENT In 1779 an engine at James Pickard’s mill situated at Snow Hill, Birmingham, was fitted with a pawl and ratchet arrangement in an early attempt to convert a Newcomen engine from water pumping to one producing rotary motion. The pawl and ratchet device was designed to achieve rotary motion taking into account all the variables of a single-acting beam engine. However, rotary motion by this method achieved little success because the rotation was irregular and this method was soon to be superseded. James Pickard’s engine had been built by a Bristol engineer, Matthew Wasborough and, with the combined efforts of the two men, the variable nature of the Newcomen engine was to come to an end when James Pickard fitted a crank and a connecting rod to the main beam to determine the outcome. To the great surprise of everyone the unpredictable nature of the Newcomen engine had been tamed at last. The crank controlled the engine and the elusive rotary motion which had been so long sought after was produced efficiently. Realising that this was a major coup, James Pickard acted quickly and applied for a patent on the 23rd August 1780, which was granted to him on the 9th December 1780. With the patent firmly in his control, Pickard was able to prevent other engineers and manufacturers from obtaining rotary motion by this simple method. A controversy ensued when James Pickard was granted a patent for the crank. It was alleged, but not proven, that James Watt was the first to consider the fitting of a crank to directly produce rotary motion from a reciprocating steam engine. As early as 1779, Watt was said to have made a model of an engine fitted with a crank which produced rotary motion. However, if this was so, why he did not patent his idea is still a mystery. He probably did make a model, because the crank had been in existence for many years on other applications - perhaps Watt did not consider a patent would ever be needed. So, the person who actually devised the means of obtaining rotary motion using this method has never been solved. The controversy raged, but if James Watt was the true father of the breakthrough, then its adaptation by James Pickard could be called the first case of industrial espionage. It was alleged that a Soho workman communicated the invention to James Pickard, who quickly realised its importance and so he obtained sole rights to its application. James Watt did not contest this patent and, apparently, took it all very calmly. Rotary motion by the crank method appears to have stimulated an intellectual challenge in Watt’s mind and, he quickly set himself the task of obtaining rotary motion without any infringement of Pickard’s patent. Page 19 of 22 ROTARY MOTION WITHOUT INFRINGEMENT OF CRANK PATENT On the 23rd February 1782, a patent was granted to Watt which covered five different methods of converting the reciprocating motion of a steam engine’s main beam into the rotary motion of an output shaft. After all these experiments, an ideal solution was to be found in the ‘sun and planet’ gearing, which quite efficiently converted the reciprocating motion of the main beam, into true rotary motion of the driven shaft. This was the first recorded use of what we now call epicydic gears and they could be used on James Watt’s engines to provide rotary motion without any infringement of James Pickard’s which Watt called that hateful patent. Figure 11 The Sun and Planet James Watt’s method of achieving rotary motion without any infringement of the Pickard patent. Page 20 of 22 The Manufacture of Steam Engines after 1800 The extended patent taken out by James Watt in 1775 for his separate condenser expired in 1800. Because this patent lasted for a total of thirty-one years, other engine manufacturers found it very difficult to compromise their engines, as they could not visualize another way of designing an engine without any infringement of Watt’s ideas covered by this patent. Boulton and Watt did not even allow other engine manufacturers to make the separate condenser under licence and, it appears ironical that such a beneficial invention should hinder the technological progress of the steam engine for such along time. Engineers must have eagerly awaited the year 1800 when engine manufacturers throughout the country could copy the separate condenser and at last build engines as efficient as those that were constructed at Boulton and Watt’s Soho Manufactory. Figure 12 A bronze medallion was struck at the Soho Manufactory to commemorate the life of James Watt in 1819. This medallion shows the great engineer and one of his standard 10 horse power engines. Page 21 of 22 OTHER STEAM ENGINE MANUFACTURERS A Manchester company even called themselves the Soho Foundry. This company, founded in 1804, had no known connection with Boulton and Watt, but they nevertheless produced almost exact copies of the Birmingham engines. A close study of the engraving, Figure 13, will reveal components identical to those manufactured in Birmingham, such as a flywheel, an eduction system and some nozzle housings. The cylinder in the right-hand corner of this engraving even has the same number of boltholes as the end flange had on the Lap Engine. Figure 13 The Soho Foundry of Peel and Williams in Manchester, making engines almost identical to the Boulton and Watt engines of Birmingham. HIGH PRESSURE ENGINES However, the real advance came about in 1804 when the Cornish engineer Richard Trevithick used only high pressure steam in a horizontally positioned double-acting cylinder for the first time. This engine was of very simple construction without any need for the very complicated mechanisms that had been necessary in order to operate the double-acting atmospheric engines of the eighteenth century. Trevithick’s double-acting rotary engine worked at 45-50 psi of steam pressure. Page 22 of 22