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[[Image:ram_hydrolic_pump.jpg|right]]
[[Image:PrincipleHydraulicRam.jpg|thumb|right|150px250px|Principle of a Hydraulic Ram pump. ]][[Image:HydraulicRamChildren.jpg|thumb|right|150px250px|Children standing around a hydraulic ram pump produced by AIDF, Phillippines .]]
A hydraulic ram pump is a water pump powered by water with a height difference. In areas where natural flows exist with a height difference of the water over a small distance, hydraulic ram pumps can be used to transport water to higher grounds without using electricity or fuel. The hydraulic ram uses the water hammer effect to develop pressure that allows a portion of the input water that powers the pump to be lifted to a point higher than where the water originally started. Apart from the kinetic energy of the water, no other source of power is needed.
==History and social context==
The hydraulic ram pump was invented in 1772 and widely used in the 19th century, but was side-tracked by the advent of the coal-powered steam engine and later by diesel powered pumps.
[http://www.ashdenawards.org/winners/aidfoundation This article] describes the impact the introduction of the hydraulic ram has had in the Philippines.
==Suitable conditions ==
A hydraulic ram pump is powered by a body of water flowing downhill with a height difference. A general rule of thumb is that the water can be pumped 30 times as high as the available drive head (the height difference of the water driving the pump). So a head of 1 m can be used to pump up water to ~30m, while a 7 m head can pump water up to 210 m.
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==Technical specificationConstruction, operations and maintenance==
A hydraulic ram has only two moving parts, a spring or weight loaded "waste" valve sometimes known as the "clack" valve and a "delivery" check valve, making it cheap to build, easy to maintain, and very reliable. In addition, there is a drive pipe supplying water from an elevated source, and a delivery pipe, taking a portion of the water that comes through the drive pipe to an elevation higher than the source.
The optimum length of the drive pipe is five-to-twelve times the vertical distance between the source and the pump, or 500-to-1000 times the diameter of the delivery pipe, whichever is less. This length of drive pipe typically results in a period between pulses of one-to-two seconds. A typical efficiency is 60%, but up to 80% is possible. The drive pipe is ordinarily straight but can be curved or even wound in a spiral. The main requirement is that it be inelastic, strong, and rigid; otherwise, it would greatly diminish the efficiency.
====Operation====[[Image:PrincipleHydraulicRam2.png|thumb|right|150px250px|Components of a hydraulic ram pump:<br>
1. Inlet — drive pipe<br>
2. Free flow at waste valve<br>
Some common operational problems are intrusion of air into the drive pipe, blockage of the intake or valves with debris, knocking due to having too little air in the pressure vessel, freezing in winter and bursting of the delivery pipe if its output is blocked or not pressure relieved.
====Manufacturing ==Costs==
==CostField experiences==
==Country experiences== ==Manuals== ==MoviesReference manuals, videos, and links==
* [http://www.youtube.com/watch?v=0ovPSSOs76U Local Hydraulic Ram pump produced by AID Foundation, Philippines]
* [http://www.youtube.com/watch?v=zIJoowE2tz0 Installation of Hydraulic Ram pumps in Afghanistan by AID Foundation, Philippines]
* [http://www.youtube.com/watch?v=u2nGlnMNXrw Ram pump produced by R.A. Initiatives, Philippines]
==External links==
* [http://en.wikipedia.org/wiki/Hydraulic_ram Hydraulic Ram article on Wikipedia]
* [http://www.ashdenawards.org/winners/aidfoundation Article on the AID Foundation hydraulic ram, winner of the Ashden Award in 2007]
* [[Solution_of_the_week_12|Akvo solution of the week 12]]
==ReferencesAcknowledgements==
* This article is adapted from the Wikipedia article [http://en.wikipedia.org/wiki/Hydraulic_ram Hydraulic Ram]
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