4. The Functioning of the Pump: Technology and Operation
Previous | 1 | 2 | 3 | 4 | 5 | 6 | 7 | Next 4. The Functioning of the Pump: Technology and Operation 4.1. How Does it Work Taqī al-Dīn's description explained how the pump works, but it was not that clear. The way how the pump works must be understood properly before analysing it. Let us start explaining it again more clearly. The best point to start with would probably be the input power source which in this case is the river, to the resultant output, which is the delivered water. The river exerts a force on the scoops, which represent the drag force. This drag force causes the wheel rotate and with it the cam shaft to rotate. But as in any mechanical system, there must be a friction force against any motion. The friction force here is due to the end bearing between the camshaft and the supporting stone wall. So the total force exerted on the wheel will be the difference between the drag force and the friction force. Each cam pushes the corresponding connecting rod causing its proximalend downwards and the distal end upwards lifting lead weight upwards, which consequently pulls the piston sucking the water from the river through the inlet clack valve. As the camshaft rotates further, the cam releases the connecting rod, and the the piston's stroke ends. Then the piston is pushed downwards by the shear weight of lead weight and pushes the water upwards through the vertical outlet pipes. As mentioned earlier, the clack valve closes when the water moves in this direction, so the water is forced to go through the other hole and through the delivery pipes. There is another clack valve at the bottom of each delivery pipe that prevents the water from going back again to the piston cylinder (see fig. 6).  | Large image | Figure 6: The six-cylinder pump at work in the river. |
4.2. Historical Assessement of the Six-Cylinder Pump The six-cylinder pump is undoubtedly the most important water machine described by Taqī al-Dīn. He felt this himself, so he said at the end of his description of it: "This is an immaculate method. It is more perfect than any of the previous ones". To assess Taqī al-Dīn's achievement, let us draw a brief picture of the pump technology in Europe in the same period. It is well known that pumps were a subject of interest for engineers in the 16th century in Europe than during the medieval times and more importance was even given to the sucking piston pump. No new pumps were invented but many changes were made to old designs in this period. The most important relevant books of machines published in the 16th century were those of Agricola (De Re Metallica, 1556) and Ramelli (Le Diverse et Artificiose Machine, 1588). In these books, the two Italian engineers described several types of pumps, and for some historians this mechanical advancement led to the invention of the steam engine by Newcomen in 1712. This invention was truly a great victory for mechanical engineering [13]. If we take all these facts into consideration and start to study Taqī al-Dīn's six-cylinder pump, before Agricola and Ramelli, we realise the historical importance of his invention. This importance becomes even clearer when we know that no machine similar to Taqī al-Dīn's pump was described either by Agricola or Ramelli. Although the mechanism of the cam or the mechanism of the trip-hammer was known to the Chinese, however, Taqī al-Dīn's design has the following features: 1. Using the cylinder block for six cylinders in one line for the first time. This is a modern and advanced mechanical technique relative to his time. It can be said that this pump is the direct grandfather for the modern six cylinder engine in-lined in one row and made in one piece. 2. Using the camshaft with six cams distributed in order on the circumference of the circle so that the cylinders work continuously and the flow of the water as well. Taqī al-Dīn advises that the number of the cylinders should not be less than three. And this advanced understanding for the continuity besides the modern mechanical balancing is what led to manufacturing the modern multi-cylinders engines and compressors. 3. Although the idea of gravity driven piston is old, however, this water piston was the one that affected future engineering. Taqī al-Dīn, contrastingly, made a lead weight on top of each piston rod that outweighs the water column inside the pipe. He said: "On top of each of the vertical rods that were fixed to the six tubes, put a lead weight that outweighs the water going through the long pipe towards the discharge point." There is a parallel design in the pump made by Samuel Morland (1625- 1695), the English academic and inventor credited with early developments in relation to computing, hydraulics and steam power. In 1675, Moreland patented a ‘plunger pump' capable of "raising great quantities of water with far less proportion of strength than can be performed by a chain or other pump". He used lead disks above the piston so that the piston is forced down by the weight pushing water up to the desired height [14]. Obviously the patent office miss out the precedence of Taqi al-Din's lead weight driven piston and pump. End Notes [13] A. Y. Al-Hassan, Taqī al-Dīn wa-‘l-handasa al mīkanīkiya al–‘arabiya, op. cit., p. 47. [14] Abbott Payson Usher, A History of Mechanical Inventions, Dover Publications, revised edition, 1988, p. 341. See also Science, Institutions & the Industrial Revolution. Previous | 1 | 2 | 3 | 4 | 5 | 6 | 7 | Next
by: FSTC, Mon 21 July, 2008
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