Dave steam 8 (darby)(36)

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Dave steam 8 (darby)(36)

  1. 1. Steam Engines<br />A series of lessons <br />by David C<br />Dec 2010<br />
  2. 2. Part 8<br />Iron<br />
  3. 3. Consider life in Europe in the late 1600s. <br />Everything is built by hand, and most things are built from timber. <br />Timber is everywhere and is easy to cut. Timber grows back. <br />
  4. 4. Consequently bridges and houses, ships and carriages; <br />all these things are made from wood. <br />What little iron and brass appears in these things <br />takes the form of nails, screws and other connectors. <br />
  5. 5. Timber is also a good fuel. <br />Timber fuels the fires that heat the castles and cottages, <br />but increasingly it is being burned in furnaces to smelt metals <br />such as lead, tin, silver, copper and iron. <br />
  6. 6. For every kilogram of pure iron extracted from a furnace, <br />20 kilograms of wood has been consumed. <br />No surprise then, that timber is growing hard to find in the late 1600s. <br />It’s being chopped up faster than it can grow back. <br />
  7. 7. The situation is so bad in some parts of Europe that local governments have actually banned <br />the burning of wood. <br />
  8. 8. Even in places where it’s still legal, <br />wood is becoming hard to find <br />and therefore becoming expensive. <br />…all of which leaves you to wonder <br />what an iron foundry is supposed to do <br />to stay in business.<br />
  9. 9. Well, the best alternative fuel is a shiny, black rock called coal. <br />
  10. 10. Coal, you may know, is the compressed remains of forests <br />buried by landslides millions of years ago. <br />It burns extremely well, but it has to be dug out of the ground <br />and cleaned and shunted from place to place in coal-wagons. <br />
  11. 11. Nevertheless it’s such a good fuel <br />that coalmining is as profitable a business <br />as copper-mining or tin-mining. <br />
  12. 12. There is a problem with coal, however, <br />as the glassblowers in Holland had discovered: <br />it produces a thick, black smoke that stains whatever it comes into contact with. <br />Glass coming out of a coal-fired furnace was the colour of coal, <br />whether you wanted it to be that colour or not. <br />
  13. 13. It was also a problem for the beer-makers of Germany. <br />To brew beer you need a fire, <br />and if you brew beer over a coal fire, <br />your beer tastes like coal.<br /> (Bleuch)<br />
  14. 14. The Germans experimented, however, <br />and came up with a clean kind of coal that they called “coal cake”. <br />
  15. 15. If you bake coal in an airtight oven for a long period of time, <br />you can boil off the sulphur and phosphor and other rubbish <br />that makes coal smoke dirty, and what’s left behind <br />is a grey rock that is almost pure hydrocarbon. <br />
  16. 16. If you bake coal in an airtight oven for a long period of time, <br />you can boil off the sulphur and phosphor and other rubbish <br />that makes coal smoke dirty, and what’s left behind <br />is a grey rock that is almost pure hydrocarbon. <br />If you burn this “coal cake”, you get a very hot fire <br />that has no fumes whatsoever. <br />
  17. 17. The Dutch saw this and before long <br />were using “coal cake” in their glass foundries. <br />Pretty soon, the glassware coming out of their foundries <br />was as colourless as the glassware we use today. <br />
  18. 18. Now why am I telling you about glassware in Holland <br />and beer-brewing in Germany? <br />
  19. 19. Now why am I telling you about glassware in Holland <br />and beer-brewing in Germany? <br />Well it turns out that the ironsmiths of England were facing <br />very much the same problem as these fellows in Europe. <br />
  20. 20. Now why am I telling you about glassware in Holland <br />and beer-brewing in Germany? <br />Well it turns out that the ironsmiths of England were facing <br />very much the same problem as these fellows in Europe. <br />Iron cooked over a coal fire absorbs the muck from the fumes <br />and this makes it brittle and useless. But iron cooked over “coal cake” <br />comes out clean and strong. <br />
  21. 21. This inspired a fellow named Abraham Darby to visit <br />the glassmakers in Holland in 1709 or so <br />and observe their procedures up close. <br />
  22. 22. MrDarby had made a name for himself <br />as a manufacturer of brass objects <br />but figured that there was considerable money to be made <br />in the iron industry if he could smelt it in a smoke-free environment. <br />
  23. 23. Well, the trip to Holland confirmed his expectations. <br />But it also gave him chance to observe something else <br />that the Dutch glassmakers were doing, something <br />that could be of extraordinary use to him in England. <br />
  24. 24. You see, Mr Darby made pistons and cylinders and boilers <br />for a certain MrNewcomenwho was <br />in the business of making steam engines. <br />MrNewcomen was unhappy about the quality of the products <br />being delivered to him, which doesn’t mean to say <br />that Darby’s engineers were doing a bad job <br />but rather that MrNewcomen’s steam engines <br />needed unusually high precision. <br />
  25. 25. Cylinders and pistons had to be perfectly round <br />and perfectly smooth and perfectly sized <br />so that the piston could move up and down inside the cylinder <br />without jamming, scratching or letting any air slip by. <br />
  26. 26. If there were bolts or rivets to hold the parts together, <br />then these joints had to be airtight under pressure at high temperature, which means they also had to be of perfect size and shape. <br />
  27. 27. Here was the solution, right before Darby’s eyes: <br />The Dutch glassmakers had learned to create molds<br />into which you poured molten glass. <br />The molds were made by pressing a desired shape into a boxful of sand <br />and hardening the sand before you disturbed it. <br />
  28. 28. As long as the thing which made the initial imprint was perfect in shape <br />– and you could afford to take your time over this – <br />then everything which came out of the mold <br />would also be perfect in shape. <br />
  29. 29. Furthermore, if you made several molds off the same original object, <br />you could make several perfect copies at the same time. <br />The Dutch had created mass production of guaranteed high-quality objects. <br />
  30. 30. Darby took the idea with him back to England. <br />In fact he even took some of the glassmakers with him <br />to help him make sand molds for brass and iron objects. <br />Very soon, Darby had a complete monopoly over <br />the brass and iron industry in the UK, <br />because the products he made were not only perfectly shaped, <br />they were cheaper. <br />
  31. 31. Now this enabled steam pumps and other machines to be built to perfection. <br />The increasing use of iron meant that cylinders and pistons <br />could be bigger and therefore more powerful, <br />and the guaranteed seals meant that <br />the engine operated for longer without requiring maintenance. <br />
  32. 32. By 1733, there would be over 100 steam pumps in operation, <br />some of them working in industries that Newcomen<br />hadn’t even thought of when he started out in 1712. <br />
  33. 33. For example, steam pumps were being used to drain swamps <br />so that they could be turned into farms or residential areas. <br />Steam pumps were delivering water to towns <br />and pouring water over wheels that operated machinery in factories. <br />Steam pumps were even pumping air through bellows into furnaces <br />so that iron could be smelted in parts of the country <br />that didn’t have rivers to power water wheels.<br />
  34. 34. It may look as though I’m coming to the end of the story, <br />but there’s more to be said about the process of sand-casting metal: <br />Sand-casting enables the production of metal objects <br />that are thinner and more delicate than can be made by hand. <br />This included measuring devices and tools for making other tools. <br />
  35. 35. By 1750, metal lathes had replaced wooden lathes, <br />and by 1760these metal lathes were controlled precisely <br />by wheels and gears so that machinery could be <br />carved out of raw metal to a precision never seen before. <br />This machinery was very often going to be the wheels and gears <br />needed to make more accurate machine tools.<br />The circle had closed on itself; <br />technology was making more technology.<br />
  36. 36. End<br />dtcoulson@gmail.com<br />

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