Water Wheel: History and Mechanism - Research Paper Example

? Water Wheel: history and mechanism Water Wheel is one of the most useful inventions of the ancient times and served as a revolutionary machine for the development of hydraulics and also agriculture. The working of a water wheel is based on the two fundamental principles of physics i.e. gravity and impulse. Water wheel finds various applications in agriculture and engineering during the ancient times and various new machines are based on the principle of water wheel. Water Wheel: history and mechanism History of Water Wheel: Primary movers, like the water wheel, have been regarded by some historians as the significant element in the evolution of technology. Invented in Hellenistic era, it was a critical juncture in the history of technology and advancement. The water wheel allowed man, for the first time in history, to use an azoic power source for agriculture and industrial production. As the use of water power spread, it had a marked impact on the technological advancement in numerous areas by enablingthe man to save labor in many industries and helped in increasing the production of the flour milling industry. Due to scarcityof early literature regarding hydraulics, the origin of water wheel is stillan unsolved puzzle for historians. The term ‘cakkavattaka’ a turning wheel, is used in the ancient Indian texts dating back to 4th century BC. On this basis, Joseph Needham a well-known British historian proposed that the machine was a water wheel but Terry S. Reynolds, the past president of the Society for the History of Technology doesn’t agree with Needham. According to him the early history of water wheel in India is vague and the term used in the Indian texts does not clearly suggest a water-powered device. The famous Greek epigrammatist Antipater of Thessalonica mentioned the use of water wheel in his poem in 1st century BC and this is also recorded in the work of Apollonius of Perge (240BC). In a nutshell, prime mover like Water wheel can be referred as a ‘key stone of technology’. From Asia to Europe Water wheel was extensively used and had played an important role in bringing up a revolutionary change in agriculture. Water wheel is one of the very first agriculture machines which helped in significantly improving the crop yield. The increase in the crop production from agricultural lands helped in evading the threat of famine for good. Change in agricultural techniques after the invention of water wheel triggered the growth of novel crops in agriculture resulting in a considerable increase in the income of farmers. With increased food production and income, the overall lifestyle was revolutionized with the invention of water wheel (Reynolds, 2003). Basic Principles of Water Wheel: The water wheel works on two fundamental principles: gravity and impulse. There are four basic types on water wheel: overshot, undershot, breast, and horizontal. The breast and overshot water wheels work on the principle of gravity; the inflowing water fills the buckets or cells thus making the weight of water effective and causing the water filled buckets to rotate under the force of gravity. While the undershot wheel and horizontal wheel are the impulse wheels, both employing the kinetic energy of the water. The inflowing water from the aqueduct strikes the blades of the wheel and kinetic energy of the water is utilized to turn the wheel. Head, the difference in level of inflowing water and existing water and flow rate are the principle criteria of deciding the type of water wheel being used. For the head differences of 2.5 to 10m and flow ratesof 100 to 200Litres/sec per meter width overshot and breast water wheels were used. Similarly for the head differences of 0.5 to 2.5m and flow rates of 500 to 950Litres/sec per meter width under shot water wheel was employed. Water Wheel-Crane:In the past reversible water wheels, capable of rotating in opposite directions were used as power pumps to avoid the mines from filling up with ground water. Those reversible water wheels were used as an underground crane; the water was allowed to strike the shafts of the water wheel and amount of striking water was controlled by the help of two levers. When the lever was pulled to right, the load carrying buckets attached to a strong chain was raised and vice versa. The three major factors affecting the rate of lift of the water wheel are the diameter of the wheel, the flow rate and the head or elevation difference. The elevation difference, difference in upstream level and downstream level of the water is decisive, greater is the difference, larger is the diameter of the water wheel and shaft can rotate at high speed thus increasing the lift capacity of the machine (Ford, 1992). The lifting capacity also varies directly with the flow rate; larger flow rate means greater lift capacity. Increase or decrease in diameter and lift capacity: Diameter varies inversely with the lift capacity of the water wheel within a specified range depending upon the type of material used in manufacturing of the water wheel. If we increase the diameter of the wheel by keeping the flow rate constant; the revolutions per minute of the wheel will decrease because by increasing the diameter we are increasing the self-weight of the wheel. Larger amount of energy is required to overcome the self-weight and frictional losses. This will affect the lift capacity of the machine as a result by increasing the diameter and keeping the flow rate constant, the speed of lift will decrease. On the other hand if we decrease the diameter of the wheel by keeping the flow rate constant the speed of the lift will increase. But the diameter below a specific point because after that the machine would become unstable (Surhorne, Timpeldon & Marseken, 2009). In present era, the water wheels are almost obsolete, with the invention of modern hydraulic devices like water turbines and water pumps the lifting of water and power generation have become much more time saving, reliable and convenient. But water wheel severed the humanity for centuries because it was the first prime mover which allowed the man to use the water power as a source to increase the production in mining and irrigation. That is why a famous Dutch historian R.J Forbes regarded the water wheel as the ‘keystone of technology’. References Ford, B. (1992). Water Wheel. Norton Coker Press. Muller, G. (2000). Water Wheels as a Power Source. Renewable Energy. Reynolds, T. (2003). Stronger Than a Hundred Men: A History of the Vertical Water Wheel. JHU Press. Surhorne, L., Timpeldon, M., & Marseken, S. (2009). Water Wheel. Betascript Publishers. Read More