Monday, August 1, 2016

Bed Time Story 30

Once upon a time there was a man named Joseph Aspdin and he was an English cement manufacturer who obtained the patent for Portland cement on 21 October 1824. Aspdin (or Aspden) was the eldest of the six children of Thomas Aspdin, a bricklayer living in the Hunslet district of Leeds, Yorkshire. He was baptised on Christmas Day, 1778. He entered his father's trade, and married Mary Fotherby at Leeds Parish Church (the Parish Church of St Peter at Leeds) on 21 May 1811.
By 1817 he had set up in business on his own in central Leeds. He must have experimented with cement manufacture during the next few years, because on 21 October 1824 he was granted the British Patent BP 5022 entitled An Improvement in the Mode of Producing an Artificial Stone, in which he coined the term "Portland cement" by analogy with the Portland stone, an oolitic limestone that is quarried on the channel coast of England, on the Isle of Portland in Dorset. See below for the text of the patent.
Almost immediately after this, in 1825, in partnership with a Leeds neighbour, William Beverley, he set up a production plant for this product in Kirkgate, Wakefield. Beverley stayed in Leeds, but Aspdin and his family moved to Wakefield (about nine miles away) at this point. He obtained a second patent, for a method of making lime, in 1825. The Kirkgate plant was closed in 1838 after compulsory purchase of the land by the Manchester and Leeds Railway Company, and the site was cleared. He moved his equipment to a second site nearby in Kirkgate.
At this time his eldest son James was working as an accountant in Leeds, and his younger son, William, was running the plant. However, in 1841, Joseph went into partnership with James, and posted a notice that William had left, and that the company would not be responsible for his debts, stating "I think it right to give notice that my late agent, William Aspdin, is not now in my employment, and that he is not authorised to receive any money, nor contract any debts on my behalf or on behalf of the new firm."
In 1843, William established his own plant at Rotherhithe, near London. There he introduced a new and substantially stronger cement, using a modified recipe for cement-making, the first "modern" Portland cement. In 1844 Joseph retired, transferring his share of the business to James. James moved to a third site at Ings Road in 1848, and this plant continued in operation until 1900. Joseph Aspdin died on 20 March 1855, at home in Wakefield.
 Aspdin called the product Portland cement because set mortar made from it resembled “the best Portland stone". Portland stone was the most prestigious building stone in use in England at the time. The patent clearly does not describe the product recognised as Portland cement today. The product was aimed at the market for stuccos and architectural pre-cast mouldings, for which a fast-setting, low-strength cement was required (see cement). It was fired at low temperature (below 1250 °C) and therefore contained no alite. With this known and so much more to learn about Joseph Aspdin i would say he is on my list for one of the most interesting inventors.



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