A water wheel is a machine used for converting the kinetic energy of free flowing water into useful forms of power. A water wheel consists of a large wooden or metal wheel, with a number of blades or buckets arranged on the outside rim forming the driving surface. Most commonly the wheel is mounted vertically on a horizontal axle. Vertical wheels can transmit power either through the axle or via a ring gear, both of which drive belts or gears. The wheel is usually mounted inside the mill building below the working floor. A jet of water is directed on to the paddles of the water wheel, causing them to turn. This is a simple system, usually used without gearing so that the axle of the water wheel becomes the spindle of the mill. This system is sometimes called the Norse mill. In a sense it is the ancestor of the modern turbine.
Water wheels were first used back in ancient Greece and continued to be in commercial use well into the 20th century, but they are no longer in common use. Water mills where used for milling flour and grinding wood into pulp for paper making, while other uses involved foundry work and machining as well as pounding linen.
Some water wheels are fed by water from a pond which has formed when a flowing stream has been dammed. A channel for the water flowing to or from a water wheel is called a mill race and is customarily divided into sections.
Development of water turbines during the Industrial revolution led to decreased popularity of water wheels. The main advantage of turbines is that ability to harness hydraulic head is much greater than the diameter of the turbine, whereas a water wheel cannot effectively harness a hydraulic head greater than its diameter. The migration from water wheels to modern turbines took about one hundred years.
Another difficulty of water wheels is their dependence on flowing water, which limits where they can be located. Modern hydroelectric dams can be viewed as the descendants of the water wheel as they take advantage of the movement of water downhill.
Water wheels were first used back in ancient Greece and continued to be in commercial use well into the 20th century, but they are no longer in common use. Water mills where used for milling flour and grinding wood into pulp for paper making, while other uses involved foundry work and machining as well as pounding linen.
Some water wheels are fed by water from a pond which has formed when a flowing stream has been dammed. A channel for the water flowing to or from a water wheel is called a mill race and is customarily divided into sections.
Development of water turbines during the Industrial revolution led to decreased popularity of water wheels. The main advantage of turbines is that ability to harness hydraulic head is much greater than the diameter of the turbine, whereas a water wheel cannot effectively harness a hydraulic head greater than its diameter. The migration from water wheels to modern turbines took about one hundred years.
Another difficulty of water wheels is their dependence on flowing water, which limits where they can be located. Modern hydroelectric dams can be viewed as the descendants of the water wheel as they take advantage of the movement of water downhill.
