Inventor of the Month: Henry Bessemer

from Wikipedia Henry Bessemer was a prolific inventor and held at least 129 patents, spanning from 1838 to 1883. His primary fame comers from inventing the Bessemer Process, a method for making steel inexpensively.

Bessemer made his first fortune was a series of six steam-powered machines for making very fine brass powder which was used as a gold paint. As he relates in his autobiography, he examined the gold paint made in Nuremberg which was the only source of gold paint at the time. He then copied and improved the product and made it capable of being made on a simple production line. It was an early example of reverse engineering where a product is analyzed, and then reconstituted. Each employee knew only his part of the process, so secrecy was assured. It was a closely guarded secret, with only a few trusted employees and members of his immediate family involved. It was a widely used alternative to a patent, and such trade secrets are still used today. The cost of the Germany-sourced powder, which was made by hand, was £5 10s 0d and he eventually reduced the price to half a crown, or about 1/40th.[4] The profits from sale of the paint allowed him to pursue his other inventions.

Bessemer patented a method for making a continuous ribbon of plate glass in 1848, but it was not commercially successful. However, he gained experience in design of furnaces, which was to be of great use for his new steel-making process.

Bessemer worked on the problem of manufacturing cheap steel for the purposes of ordnance production from 1850 to 1855 when he patented his method. On August 24, 1856 Bessemer first described the process to a meeting of the British Association in Cheltenham which he titled "The Manufacture of Iron Without Fuel." It was published in full in The Times. The Bessemer process involved using oxygen in air blown through molten pig iron to burn off the impurities and thus create steel.

Many industries were constrained by the lack of steel, being reliant on cast iron and wrought iron alone. Examples included railway structures such as bridges and tracks, where the treacherous nature of cast iron was keenly felt by many engineers and designers. There had been many accidents when cast iron beams collapsed suddenly. The problem continued until all cast iron under-bridges were replaced by steel structures. Wrought iron structures were much more reliable with very few failures.

Though this process is no longer commercially used, at the time of its invention it was of enormous industrial importance because it lowered the cost of production steel, leading to steel being widely substituted for cast iron. Bessemer's attention was drawn to the problem of steel manufacture in the course of an attempt to improve the construction of guns.

Bessemer licensed the patent for his process to five Ironmasters, but from the outset, the companies had great difficulty producing good quality steel. Mr Göransson, a Swedish ironmaster, using the purer charcoal pig iron of that country, was the first to make good steel by the process, but only after many attempts. His results prompted Bessemer to try a purer iron obtained from Cumberland hematite, but even with this he had only limited success until Robert Forester Mushet, who had carried out thousands of experiments at Darkhill, in the Forest of Dean, showed that adding an exact amount of carbon and manganese, in the form of spiegeleisen, improved the quality of the finished product, increasing its malleability.

When Bessemer tried to induce makers to take up his improved system, he met with general rebuffs and was eventually driven to undertake the exploitation of the process himself. He erected steelworks in Sheffield, on ground purchased with the help of friends, and began to manufacture steel. At first the output was insignificant, but gradually the magnitude of the operations was enlarged until the competition became effective, and steel traders generally became aware that the firm of Henry Bessemer & Co. was underselling them to the extent of $20 a ton. This argument to the pocket quickly had its effect, and licenses were applied for in such numbers that, in royalties for the use of his process, Bessemer received a sum in all considerably exceeding a million pounds sterling.

Patent Battles
Of course, patents of such obvious value did not escape criticism, and invalidity was freely urged against them on various grounds. But Bessemer was fortunate enough to maintain them intact without litigation, though he found it advisable to buy up the rights of one patentee, while in the case of Robert Forester Mushet, was freed from anxiety by the patent being allowed to lapse in 1859 through non-payment of fees.

Mushet's procedure was not absolutely essential and Bessemer proved this in 1865 by exhibiting a series of steel samples made using his process alone, but the value of Mushet's procedure was shown by its near universal adoption in conjunction with the Bessemer Process. Whether or not Mushet's patents could have been sustained is not known, but in 1866 Robert Mushet's 16 year old daughter traveled to London alone to confront Henry Bessemer at his offices, arguing that Bessemer's success was based on the results of her father’s work. Bessemer decided to pay Mushet an annual pension of £300, a very considerable sum, which he paid for 25 years; and it is possible that this was done with a view to keeping the Mushets from legal action.

In 1866, Bessemer also provided finance for Zerah Colburn, the American locomotive engineer and journalist, to start a new weekly engineering newspaper called Engineering, and based in Bedford Street, London. It was not until many years later that the name of Colburn's benefactor was revealed. Prior to the launch of Engineering, Colburn, through the pages of The Engineer, had given support to Bessemer's work on steel and steelmaking.

Other Inventions
Bessemer's autobiography describes all of his inventions, some in great detail, as one might expect from such an innovative man. Among Bessemer's numerous other inventions were movable dies for embossed postage stamps, and a screw extruder for more efficiently extracting sugar from sugar cane. After suffering from seasickness in 1868, he designed the SS Bessemer (also called the "Bessemer Saloon"), a passenger steamship with a cabin on gimbals designed to stay level, however rough the sea, to save her passengers from seasickness. The mechanism - hydraulics controlled by a steersman watching a spirit level - worked in model form and in a trial version built in his garden in Denmark Hill, London. However it never received a proper seagoing test as, when the ship demolished part of the Calais pier on her maiden voyage, investor confidence was lost and the ship was scrapped.

Bessemer also obtained a patent in 1857 for the casting of metal between counter-rotating rollers - a forerunner of today's continuous casting processes and remarkably, Bessemer's original idea has been implemented in the direct continuous casting of steel strip.

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