A hydraulic ram or hydram uses the energy of a waterfall to pump water higher than the height of the waterfall, with a very simple hydraulic and mechanical feature. It was invented by Joseph-Michel Montgolfier, known for building the first air-balloon in 1782 with his brother Jacques-Etienne. In 1772, Joseph Montgolfier came up with the idea to apply the water hammer effect to a simple mechanism to pump up water for the family paper mill in Vidalon (France). The water hammer effect can be observed when a tap is suddenly turned off : due to water’s inert force, the canalization is subject to a shock resulting in a noise. The hydraulic ram takes in water at one “hydraulic head” (pressure) and flow rate, and outputs water at a higher hydraulic head and lower flow rate. The water hammer effect is used to build up pressure allowing a portion of the water that powers the pump to be lifted to a point that is higher than where the water originally started. The hydraulic ram is sometimes used in remote areas, where there is both a source of low-head hydropower and a need for pumping water to a destination located higher than the source. In this situation, the ram very useful, since no outside source of power is required other than the kinetic energy of flowing water.
See also :
http://walton.fr/ram/hydraulic-RAM/French/le-belier.html
http://chateauduloir.over-blog.com/article-231430.html
http://www.belier-inox.fr/fabriquez-votre-belier-p867652
