Sejarah geografi JAMES WATT penemu Mesin uap

JAMES WATT – PENEMU MESIN UAP

   

 James Watt (Greenock, Skotlandia, 19 Januari 1736 - Birmingham, Inggris, 19 Agustus 1819) ialah seorang insinyur besar dari Skotlandia, Britania Raya. Ia berhasil menciptakan mesin uap pertama yang efisien. Ternyata mesin uap ini merupakan salah satu kekuatan yang mendorong terjadinya Revolusi Industri, khususnya di Britania dan Eropa pada umumnya. Untuk menghargai jasanya, nama belakangnya yaitu Watt digunakan sebagai nama satuan daya, misalnya daya mesin dan daya listrik.

James Watt, orang Skotlandia yang sering dihubungkan dengan penemu mesin uap, adalah tokoh kunci Revolusi Industri. Sebenarnya, Watt bukanlah orang pertama yang membikin mesin uap. Rancangan serupa disusun pula oleh Hero dari Iskandariah pada awal tahun Masehi. Di tahun 1686 Thomas Savery membikin paten sebuah mesin uap yang digunakan untuk memompa air, dan di tahun 1712, seorang Inggris Thomas Newcomen, membikin pula paten barang serupa dengan versi yang lebih sempurna, namun mesin ciptaan Newcomen masih bermutu rendah dan kurang efisien, hanya bisa digunakan untuk pompa air dari tambang batubara.


Watt menjadi tertarik dengan ihwal mesin uap di tahun 1764 tatkala dia sedang membetulkan mesin ciptaan Newcomen. Meskipun Watt cuma peroleh pendidikan setahun sebagai tukang pembuat perkakas, tetapi dia punya bakat pencipta yang besar. Penyempurnaan-penyempurnaan yang dilakukannya terhadap mesin bikinan Newcomen begitu penting, sehingga layaklah menganggap sesungguhnya Wattlah pencipta pertama mesin uap yang praktis.

Keberhasilan Watt pertama yang dipatenkannya di tahun 1769 adalah penambahan ruang terpisah yang diperkokoh. Dia juga membikin isolasi pemisah untuk mencegah menghilangnya panas pada silinder uap, dan di tahun 1782 dia menemukan mesin ganda. Dengan beberapa perbaikan kecil, pembaruan ini menghasilan peningkatan efisiensi mesin uap dengan empat kali lipat atau lebih. Dalam praktek, peningkatan efisiensi ini memang merupakan hasil dari suatu kecerdasan namun tidaklah begitu merupakan peralatan yang b

ermanfaat dan bukan pula punya kegunaan luar biasa ditilik dari sudut industri.

Watt juga menemukan (di tahun 1781) seperangkat gerigi untuk mengubah gerak balik mesin sehingga menjadi gerak berputar. Alat ini meningkatkan secara besar-besaran penggunaan mesin uap. Watt juga berhasil menciptakan pengontrol gaya gerak melingkar otomatis (tahun 1788), yang menyebabkan kecepatan mesin

dapat secara otomatis diawasi. Juga menciptakan alat pengukur bertekanan (tahun 1790), alat penghitung kecepatan, alat petunjuk dan alat pengontrol uap sebagai tambahan perbaikan lain-lain peralatan.

Watt sendiri tidak punya bakat bisnis. Tetapi, di tahun 1775 dia melakukan persekutuan dengan Matthew Boulton, seorang insinyur, dan seorang pengusaha yang cekatan. Selama dua puluh lima tahun sesudah itu, perusahaan Watt dan Boulton memproduksi sejumlah besar mesin uap dan keduanya menjadi kaya raya. Mesin uap bekerja ganda penemuan Watt tahun 1769 Memang sulit melebih-lebihkan arti penting mesin uap. Sebab, memang banyak penemuan-penemuan lain yang memegang peranan penting mendorong berkembangnya Revolusi Industri. Misalnya, perkembangan dunia tambang, metalurgi, dan macam-macam peralatan mesin. Sekoci yang meluncur bolak-balik dalam mesin tenun (penemuan John Kay tahun 1733), atau alat pintal (penemuan James Hargreaves tahun 1764) semuanya terjadi mendahului kreasi Watt. Sebagian terbesar dari penemuan-penemuan itu hanyalah merupakan penyempurnaan yang kurang berarti dan tak satu pun punya arti vital dalam kaitan dengan bermulanya Revolusi Industri. Lain halnya dengan penemuan mesin uap yang memainkan peranan penting dalam Revolusi Industri, yang tampaknya keadaan akan mengalami bentuk lain. Sebelumnya, meskipun tenaga uap digunakan untuk kincir angin dan putaran air, sumber pokok tenaga mesin terletak pada tenaga manusia. Faktor ini amat membatasi kapasitas produksi industri. Berkat penemuan mesin uap, keterbatasan ini tersingkirkan. Sejumlah besar energi kini dapat disalurkan untuk hal-hal yang produktif yang menanjak dengan teramat derasnya. Embargo minyak tahun 1973 membuat kita sadar betapa sengsaranya jika bahan energi berkurang dan mampu melumpuhkan industri. Pengalaman ini, pada tingkat tertentu, mendorong kita membayangkan arti penting Revolusi Industri berkat penemuan James Watt.

Di samping manfaat tenaga untuk pabrik, mesin uap juga punya guna besar di bidang-bidang lain. Di tahun 1783, Marquis de Jouffroy di Abbans berhasil menggunakan mesin uap untuk penggerak kapal. Di tahun 1804, Richard Trevithick menciptakan lokomotif uap pertama. Tak satu pun dari model-model pemula itu berhasil secara komersial. Dalam tempo beberapa puluh tahun, barulah baik kapal maupun kereta api menghasilkan revolusi baik di bidang pengangkutan darat maupun laut.

Revolusi Industri berlangsung hampir berbarengan dengan Revolusi Amerika maupun Perancis. Meskipun waktu itu tampaknya sepele, kini tampak jelas betapa Revolusi Industri itu seakan digariskan mempunyai makna jauh lebih penting untuk peri kehidupan manusia ketimbang arti penting revolusi politik. James Watt, oleh sebab itu tergolong salah seorang yang punya pengaruh penting dalam sejarah.
Mesin uap model James Watt banyak dikonversi karena menjadi mesin yang paling efisien yang sangat mendukung dalam pengembangan indutri di Inggris. Mesin uap ini juga mendukung dalam kemajuan transportasi di kemudian hari, seperti kapal uap dan lokomotif. Untuk menghargai jasanya berikut ini beberapa pengabadian namnya:

1. Unit besaran listrik menggunakan namanya (watt)
2. Namanya juga diabadikan menjadi nama universitas (Universitas Heriot-Watt Edinburgh)
3. Ia juga dikenang oleh Lunar Society moonstones dengan mengabadikan dalamsebuah patung.
4. Sebuah sekolah ternama di Birmingham juga menggunakan namanya
5. Ada 4 perguruan tinggi di Skotlandia yang menggunakan namanyayaitu James Watt College Kilwinning (North Ayrshire Kampus) dan Greenock (2 di Greenock, Finnart Kampus dan Waterfront Kampus)

                     

Biography

Bust of Watt in the Scottish National Portrait Gallery

James Watt was born on 19 January 1736 in Greenock, Renfrewshire, a seaport on the Firth of Clyde.[3] His father was a shipwright, ship owner and contractor, and served as the town's chief baillie,[4] while his mother, Agnes Muirhead, came from a distinguished family and was well educated. Both were Presbyterians and strong Covenanters.[5] Watt's grandfather, Thomas Watt, was a mathematics teacher and baillie to the Baron of Cartsburn.[6] Despite being raised by religious parents, he later on became a deist.[7][8]

Watt did not attend school regularly; initially he was mostly schooled at home by his mother but later he attended Greenock Grammar School.[9] He exhibited great manual dexterity, engineering skills and an aptitude for mathematics, while Latin and Greek failed to interest him.

When he was eighteen, his mother died and his father's health began to fail. Watt travelled to London to study instrument-making for a year, then returned to Scotland, settling in the major commercial city of Glasgow intent on setting up his own instrument-making business. He made and repaired brass reflecting quadrants, parallel rulers, scales, parts for telescopes, and barometers, among other things. Because he had not served at least seven years as an apprentice, the Glasgow Guild of Hammermen (which had jurisdiction over any artisans using hammers) blocked his application,[10] despite there being no other mathematical instrument makers in Scotland.[11]

Watt was saved from this impasse by the arrival of astronomical instruments at the University of Glasgow, instruments that required expert attention.[12] Watt restored them to working order and was remunerated. These instruments were eventually installed in the Macfarlane Observatory. Subsequently three professors offered him the opportunity to set up a small workshop within the university. It was initiated in 1757 and two of the professors, the physicist and chemist Joseph Black as well as the famed Adam Smith, became Watt's friends.[13]

At first he worked on maintaining and repairing scientific instruments used in the university, helping with demonstrations, and expanding the production of quadrants. In 1759 he formed a partnership with John Craig, an architect and businessman, to manufacture and sell a line of products including musical instruments and toys. This partnership lasted for the next six years, and employed up to sixteen workers. Craig died in 1765. One employee, Alex Gardner, eventually took over the business, which lasted into the twentieth century.[14]

In 1764, Watt married his cousin Margaret (Peggy) Miller, with whom he had five children, two of whom lived to adulthood: James Jr. (1769–1848) and Margaret (1767–1796). His wife died in childbirth in 1772. In 1777 he was married again, to Ann MacGregor, daughter of a Glasgow dye-maker, with whom he had two children: Gregory (1777–1804), who became a geologist and mineralogist,[15] and Janet (1779–1794). Ann died in 1832. Between 1777 and 1790 he lived in Regent Place, Birmingham[16]

Early experiments with steam

Original condenser by Watt (Science Museum)

In 1759 Watt's friend, John Robison, called his attention to the use of steam as a source of motive power.[17] The design of the Newcomen engine, in use for almost 50 years for pumping water from mines, had hardly changed from its first implementation. Watt began to experiment with steam though he had never seen an operating steam engine. He tried constructing a model. It failed to work satisfactorily, but he continued his experiments and began to read everything he could about the subject. He came to realise the importance of latent heat in understanding the engine, which, unknown to Watt, his friend, Joseph Black, had previously discovered some years before. Understanding of the steam engine was in a very primitive state, for the science of thermodynamics was not in place for another 100 years or so.

In 1763, Watt was asked to repair a model Newcomen engine belonging to the university.[17] Even after repair, this engine only barely worked. After much experimentation, Watt demonstrated that about three-quarters of the heat of the steam was being wasted – consumed in heating the engine cylinder on every cycle.[18] This energy was wasted because later in the cycle, cold water was injected into the cylinder to condense the steam to reduce its pressure. Thus the engine expended much of its energy in repeatedly heating the cylinder rather than in delivering mechanical force.

Watt's critical insight, arrived at in May 1765,[19] was to cause the steam to condense in a separate chamber apart from the piston, and to maintain the temperature of the cylinder at the same temperature as the injected steam (by surrounding it with a "steam jacket").[18] This meant that very little heat was absorbed into the cylinder itself on each cycle, and thus more heat from the steam was made available to perform useful work. Watt had a working model later that same year.

The ruin of Watt's cottage workshop at Kinneil House

Cylinder fragment of Watt's first operational engine at the Carron Works, Falkirk

Despite a potentially workable design, there were still substantial difficulties in constructing a full-scale engine. This required more capital, some of which came from Black. More substantial backing came from John Roebuck, the founder of the celebrated Carron Iron Works, near Falkirk, with whom he now formed a partnership. Roebuck lived at Kinneil House in Bo'ness, during which time Watt worked at perfecting his steam engine, in a cottage adjacent to the house. The shell of the cottage, and a very large part of one of his projects, still exist to the rear.[20]

The principal difficulty was in machining the piston and cylinder. Iron workers of the day were more like blacksmiths than modern machinists and were unable to produce the components with sufficient precision. Much capital was spent in pursuing the ground-breaking patent on Watt's invention. Strapped for resources, Watt was forced to take up employment first as a surveyor, then as a civil engineer for eight years.[21]

Roebuck went bankrupt, and Matthew Boulton, who owned the Soho Foundry works near Birmingham, acquired his patent rights. An extension of the patent to 1800 was successfully obtained in 1775.[22]

Through Boulton, Watt finally had access to some of the best ironworkers in the world. The difficulty of the manufacture of a large cylinder with a tightly fitting piston was solved by John Wilkinson who had developed precision boring techniques for cannon making at Bersham, near Wrexham, North Wales. Watt and Boulton formed a hugely successful partnership (Boulton and Watt) which lasted for the next twenty-five years.

First engines

Engraving of a 1784 steam engine designed by Boulton and Watt.

Main article: Watt steam engine

In 1776, the first engines were installed and working in commercial enterprises. These first engines were used to power pumps and produced only reciprocating motion to move the pump rods at the bottom of the shaft. The design was commercially successful, and for the next five years Watt was very busy installing more engines, mostly in Cornwall for pumping water out of mines.

These early engines were not manufactured by Boulton and Watt, but were made by others according to drawings made by Watt, who served in the role of consulting engineer. The erection of the engine and its shakedown was supervised by Watt, at first, and then by men in the firm's employ. These were large machines. The first, for example, had a cylinder with a diameter of some 50 inches and an overall height of about 24 feet, and required the construction of a dedicated building to house it. Boulton and Watt charged an annual payment, equal to one third of the value of the coal saved in comparison to a Newcomen engine performing the same work.

The field of application for the invention was greatly widened when Boulton urged Watt to convert the reciprocating motion of the piston to produce rotational power for grinding, weaving and milling. Although a crank seemed the obvious solution to the conversion Watt and Boulton were stymied by a patent for this, whose holder, James Pickard, and associates proposed to cross-license the external condenser. Watt adamantly opposed this and they circumvented the patent by their sun and planet gear in 1781.

Over the next six years, he made a number of other improvements and modifications to the steam engine. A double acting engine, in which the steam acted alternately on the two sides of the piston was one. He described methods for working the steam "expansively" (i.e., using steam at pressures well above atmospheric). A compound engine, which connected two or more engines was described. Two more patents were granted for these in 1781 and 1782. Numerous other improvements that made for easier manufacture and installation were continually implemented. One of these included the use of the steam indicator which produced an informative plot of the pressure in the cylinder against its volume, which he kept as a trade secret. Another important invention, one which Watt was most proud of, was the parallel motion which was essential in double-acting engines as it produced the straight line motion required for the cylinder rod and pump, from the connected rocking beam, whose end moves in a circular arc. This was patented in 1784. A throttle valve to control the power of the engine, and a centrifugal governor, patented in 1788,[23] to keep it from "running away" were very important. These improvements taken together produced an engine which was up to five times as efficient in its use of fuel as the Newcomen engine.

Because of the danger of exploding boilers, which were in a very primitive stage of development, and the ongoing issues with leaks, Watt restricted his use of high pressure steam – all of his engines used steam at near atmospheric pressure.

Patent trials

A steam engine built to James Watt's patent in 1848 at Freiberg in Germany

Edward Bull started constructing engines for Boulton and Watt in Cornwall in 1781. By 1792 he had started making engines of his own design, but which contained a separate condenser, and so infringed Watt's patents. Two brothers, Jabez Carter Hornblower and Jonathan Hornblower Jnr also started to build engines about the same time. Others began to modify Newcomen engines by adding a condenser, and the mine owners in Cornwall became convinced that Watt's patent could not be enforced. They started to withhold payments due to Boulton and Watt, which by 1795 had fallen. Of the total £21,000 (£1,890,000 as of 2014) owed, only £2,500 had been received. Watt was forced to go to court to enforce his claims.[24]

He first sued Bull in 1793. The jury found for Watt, but the question of whether or not the original specification of the patent was valid was left to another trial. In the meantime, injunctions were issued against the infringers, forcing their payments of the royalties to be placed in escrow. The trial on determining the validity of the specifications which was held in the following year was inconclusive, but the injunctions remained in force and the infringers, except for Jonathan Hornblower, all began to settle their cases. Hornblower was soon brought to trial and the verdict of the four judges (in 1799) was decisively in favour of Watt. Their friend John Wilkinson, who had solved the problem of boring an accurate cylinder, was a particularly grievous case. He had erected about twenty engines without Boulton's and Watts' knowledge. They finally agreed to settle the infringement in 1796.[25] Boulton and Watt never collected all that was owed them, but the disputes were all settled directly between the parties or through arbitration. These trials were extremely costly in both money and time, but ultimately were successful for the firm.

Copying machine

Before 1780 there was no good method for making copies of letters or drawings. The only method sometimes used was a mechanical one using linked multiple pens. Watt at first experimented with improving this method, but soon gave up on this approach because it was so cumbersome. He instead decided to try to physically transfer some ink from the front of the original to the back of another sheet, moistened with a solvent, and pressed to the original. The second sheet had to be thin, so that the ink could be seen through it when the copy was held up to the light, thus reproducing the original exactly.[26][27]

Watt started to develop the process in 1779, and made many experiments to formulate the ink, select the thin paper, to devise a method for wetting the special thin paper, and to make a press suitable for applying the correct pressure to effect the transfer. All of these required much experimentation, but he soon had enough success to patent the process a year later. Watt formed another partnership with Boulton (who provided financing) and James Keir (to manage the business) in a firm called James Watt and Co. The perfection of the invention required much more development work before it could be routinely used by others, but this was carried out over the next few years. Boulton and Watt gave up their shares to their sons in 1794.[28] It became a commercial success and was widely used in offices even into the twentieth century.

Chemical experiments

From an early age Watt was very interested in chemistry. In late 1786, while in Paris, he witnessed an experiment by Berthollet in which he reacted hydrochloric acid with manganese dioxide to produce chlorine. He had already found that an aqueous solution of chlorine could bleach textiles, and had published his findings, which aroused great interest among many potential rivals. When Watt returned to Britain, he began experiments along these lines with hopes of finding a commercially viable process. He discovered that a mixture of salt, manganese dioxide and sulphuric acid could produce chlorine, which Watt believed might be a cheaper method. He passed the chlorine into a weak solution of alkali, and obtained a turbid solution that appeared to have good bleaching properties. He soon communicated these results to James McGrigor, his father-in-law, who was a bleacher in Glasgow. Otherwise he tried to keep his method a secret.[29]

With McGrigor and his wife Annie, he started to scale up the process, and in March 1788, McGrigor was able to bleach 1500 yards of cloth to his satisfaction. About this time Berthollet discovered the salt and sulphuric acid process, and published it so it became public knowledge. Many others began to experiment with improving the process, which still had many shortcomings, not the least of which was the problem of transporting the liquid product. Watt's rivals soon overtook him in developing the process, and he dropped out of the race. It was not until 1799, when Charles Tennant patented a process for producing solid bleaching powder (calcium hypochlorite) that it became a commercial success.

By 1794 Watt had been chosen by Thomas Beddoes to manufacture apparatus to produce, clean and store gases for use in the new Pneumatic Institution at Hotwells in Bristol. Watt continued to experiment with various gases for several years, but by 1797 the medical uses for the "factitious airs" had come to a dead end.[30]

Scientific apparatus designed by Boulton and Watt in preparation of the Pneumatic Institution in Bristol

Personality

Watt combined theoretical knowledge of science with the ability to apply it practically. Humphry Davy said of him "Those who consider James Watt only as a great practical mechanic form a very erroneous idea of his character; he was equally distinguished as a natural philosopher and a chemist, and his inventions demonstrate his profound knowledge of those sciences, and that peculiar characteristic of genius, the union of them for practical application".[31]

He was greatly respected[32] by other prominent men of the Industrial Revolution. He was an important member of the Lunar Society, and was a much sought-after conversationalist and companion, always interested in expanding his horizons.[33] His personal relationships with his friends and partners were always congenial and long-lasting.

Watt was a prolific correspondent. During his years in Cornwall, he wrote long letters to Boulton several times per week. He was averse to publishing his results in, for example, the Philosophical Transactions of the Royal Society however, and instead preferred to communicate his ideas in patents.[34] He was an excellent draughtsman.

He was a rather poor businessman, and especially hated bargaining and negotiating terms with those who sought to use the steam engine. In a letter to William Small in 1772, Watt confessed that "he would rather face a loaded cannon than settle an account or make a bargain."[35] Until he retired, he was always much concerned about his financial affairs, and was something of a worrier. His health was often poor. He was subject to frequent nervous headaches and depression.

Soho Foundry

At first the partnership made the drawing and specifications for the engines, and supervised the work to erect it on the customers property. They produced almost none of the parts themselves. Watt did most of his work at his home in Harper's Hill in Birmingham, while Boulton worked at the Soho Manufactory. Gradually the partners began to actually manufacture more and more of the parts, and by 1795 they purchased a property about a mile away from the Soho manufactory, on the banks of the Birmingham Canal, to establish a new foundry for the manufacture of the engines. The Soho Foundry formally opened in 1796 at a time when Watt's sons, Gregory and James Jr. were heavily involved in the management of the enterprise. In 1800, the year of Watt's retirement, the firm made a total of forty-one engines.[36]

Later years

"Heathfield", Watt's house in Handsworth, Birmingham

James Watt's workshop

Watt retired in 1800, the same year that his fundamental patent and partnership with Boulton expired. The famous partnership was transferred to the men's sons, Matthew Robinson Boulton and James Watt Jr. Longtime firm engineer William Murdoch was soon made a partner and the firm prospered.

Watt continued to invent other things before and during his semi-retirement. Within his home in Handsworth Heath, Staffordshire, Watt made use of a garret room as a workshop, and it was here that he worked on many of his inventions.[37] Among other things, he invented and constructed several machines for copying sculptures and medallions which worked very well, but which he never patented.[38] One of the first sculptures he produced with the machine was a small head of his old professor friend Adam Smith. He maintained his interest in civil engineering and was a consultant on several significant projects. He proposed, for example, a method for constructing a flexible pipe to be used for passing water under the Clyde at Glasgow.[39]

He and his second wife travelled to France and Germany, and he purchased an estate in Wales at Doldowlod House, one mile south of Llanwrthwl, which he much improved.

In 1816 he took a trip on The Comet, a product of his inventions, to revisit his home town of Greenock.[40]

He died on 25 August 1819 at his home "Heathfield" in Handsworth, Birmingham, England at the age of 83. He was buried on 2 September.
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