06.08.2016
Pascal was the first to show, both theoretically and in practice, what hydraulic power could do. We look at his contribution, and at those of the men who stood on his shoulders.
Blaise Pascal was a Frenchman of provincial origins, born in 1623 and the son of a well to do tax collector, who taught him mathematics. The boy was soon teaching himself, and extending his inquisitive gaze to the natural world. Among his early achievements was a practical calculating machine which helped his father in the repetitive calculations his calling entailed. He lived on the eve of Newtonian Physics, and was just as interested in philosophy as in mathematics and physics.
But it is in the field of hydrodynamic that we in the hydraulics industry find our great debt to Pascal. It was he who gave us the scientific principles on which hydraulic systems depend, together with the mathematical relationships that govern their operation.
Pascal’s Law states that a change of pressure in an incompressible fluid is transmitted equally throughout the fluid. That principle might seem almost intuitively true to us today, but in Pascal’s it was a profound insight. An intensely practical man, he applied the principle immediately, inventing the syringe and, more importantly for our industry, the hydraulic press, harnessing the force-multiplying power of the principle he had revealed.
The hydraulic press must have stunned the forgemasters of Pascal’s day, and its awesome power continues to fascinate, with a Youtube channel devoted to watching every conceivable article meet the same, inevitable end at its hands.
Joseph Bramah
Pascal did not industrialise his press, probably because the necessary machining precision was not yet available. When it arrived, over a century later, that precision showed up in the North of England.
Joseph Bramah (1748-1814) was the ideal man to tackle the challenges of machining very precise parts. His West Yorkshire home was only beginning to acquire the forest of smokestacks and mean terraced streets it would later have, and he himself came from yeoman farming stock.
Unlike Pascal, who made only a handful of his calculators and presses, Bramah was born into an age in which practical application and improvement was part of the zeitgeist. Newton, a hundred years earlier, had shown that it was possible to predict with great accuracy the outcomes of extremely complex processes. The implications of Newton’s laws had caught the classical imagination, evoking a clockwork universe ticking away in a sort of God-given equipoise.
Completing his apprenticeship as a cabinet-maker, Bramah moved to London and lived in modestly prosperous circumstances, working for a Mr Allen, who installed water closets. Mr Allen would install the loos, built to a patented design, and it was Bramah’s job to encase them in suitable cabinetry. Bramah noticed that there was a flaw in the design for which Allen was supplying a makeshift modification. Bramah had the nous to patent the improved loo, and to start manufacturing them.
The Challenge Lock
Probably his services to the smallest room in the house gave Bramah valuable insights into the behaviour of fluids, but Bramah’s next departure was the one that really set him on the path to the engineering precision that hydraulic engineering demands. He had attended a couple of lectures on lock making, Bramah made one of his own. He patented it and started manufacturing it. Clearly a man who understood marketing, he promoted his lock as The Challenge Lock, displaying one in his shop window, next to an inscription that read “The artist who can make an instrument that will pick or open this lock shall receive 200 guineas the moment it is produced.”.
Bramah challenge stood until the 1851 Great Exhibition, when the prize was claimed by a visiting American. But by then the Challenge had done its job. Largely to support the demands of his lock-making enterprise Bramah, aided by employees such as Henry Maudeslay devoted much of his energy to the creation of ever-more capable and precise machine tools – the real vertebrae of the Industrial Revolution.
Bramah’s most important product was undoubtedly his hydraulic press. His gift to hydraulics, though was precision. Until well into the 70’s, the used car dealers of London would refer to a car in particularly fine fettle as “a real Bramah”.
William Armstrong
Modern hydraulics really took off in the hands of William George Armstrong (1810-1900). Born in Newcastle, England just four years before Bramah’s death, Armstrong at first went into the law, but retained his boyhood interest in mechanics, and in angling. Fishing one day near his home, he saw a waterwheel powering a small mill. He saw how much of the available power was being wasted, and determined to build a more efficient one. That set him off on a trajectory that was to take him deep into practical hydraulics. He invented the hydraulic accumulator, a key component in modern hydraulics. When Newcastle’s Corporation conceived a scheme to bring drinking water from reservoirs in the moors to the residents of Newcastle, Armstrong spotted that the water would have a head considerably greater than was needed for domestic supply, and proposed to use the excess power in a hydraulic crane at the busy port of Newcastle. So successful was the crane that two more were built, and Armstrong quickly industrialised his creation.
Harry Vickers.
The last great innovator in the hydraulics story was an American. Harry Franklin Vickers (1898-1977), who grew up in Montana and Southern California. As a teenager, his native ability was spotted by Zane Grey, a popular writer of cowboy stories. Grey paid for Vickers’ rudimentary education to be extended to include science and calculus. When the US went to war in France, Vickers served in the Signals Corps, and this added insights in early electronics to his precocious engineering acumen.
Vickers has been called The Father of Industrial Hydraulics. Whether or not that does justice to the pioneers we have already discussed, Vickers certainly invented key components, such as the balanced vane pump, that propelled hydraulics into hitherto undreamed of power delivery applications, and upon which hydraulics continues to depend.