A hydraulic ram, or hydram, is a
cyclic water pump powered by
hydropower
Hydropower (from el, ὕδωρ, "water"), also known as water power, is the use of falling or fast-running water to produce electricity or to power machines. This is achieved by converting the gravitational potential or kinetic energy of ...
. It takes in water at one "
hydraulic head" (pressure) and flow rate, and outputs water at a higher hydraulic head and lower flow rate. The device uses the
water hammer
Hydraulic shock (colloquial: water hammer; fluid hammer) is a pressure surge or wave caused when a fluid in motion, usually a liquid but sometimes also a gas is forced to stop or change direction suddenly; a momentum change. This phenomenon c ...
effect to develop pressure that allows a portion of the input water that powers the
pump
A pump is a device that moves fluids ( liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic energy. Pumps can be classified into three major groups according to the method the ...
to be lifted to a point 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 higher in elevation than the source. In this situation, the ram is often useful, since it requires no outside source of
power other than the
kinetic energy
In physics, the kinetic energy of an object is the energy that it possesses due to its motion.
It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its a ...
of flowing water.
History
The
Alhambra, built by Nasrid Sultan
Ibn al-Ahmar
, predecessor = None
, successor = Muhammad II
, succession2 = Taifa King of Arjona
, reign2 =
, birth_date =
, birth_place = Arjona, Almohad Caliphate
, death_date =
, death_place = near Granada, Emirate of Granada ...
of Granada beginning AD1238, used a hydram to raise water. Through a first reservoir, filled by a channel from the
Darro River, water emptied via a large vertical channel into a second reservoir beneath, creating a whirlpool that in turn propelled water through a much smaller pipe up six metres whilst most water drained into a second, slightly larger pipe.
In 1772,
John Whitehurst of
Cheshire
Cheshire ( ) is a ceremonial and historic county in North West England, bordered by Wales to the west, Merseyside and Greater Manchester to the north, Derbyshire to the east, and Staffordshire and Shropshire to the south. Cheshire's coun ...
,
England
England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe ...
, invented a manually controlled precursor of the hydraulic ram called the "pulsation engine" and installed the first one at
Oulton, Cheshire
In the early 18th century the Oulton Estate was home to the Egerton family
and comprised a manor house and a formal garden surrounded by farmland in Cheshire, England. Later in the century the farmland was converted into a park. The estate ...
to raise water to a height of . In 1783, he installed another in
Ireland
Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...
. He did not
patent
A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an sufficiency of disclosure, enabling disclo ...
it, and details are obscure, but it is known to have had an air vessel.
The first self-acting ram pump was invented by the Frenchman
Joseph Michel Montgolfier
The Montgolfier brothers – Joseph-Michel Montgolfier (; 26 August 1740 – 26 June 1810) and Jacques-Étienne Montgolfier (; 6 January 1745 – 2 August 1799) – were aviation pioneers, balloonists and paper manufacturers from the commune An ...
(best known as a co-inventor of the
hot air balloon) in 1796 for raising water in his
paper mill at
Voiron. His friend
Matthew Boulton took out a British patent on his behalf in 1797. The sons of Montgolfier obtained a British patent for an improved version in 1816, and this was acquired, together with Whitehurst's design, in 1820 by
Josiah Easton, a
Somerset
( en, All The People of Somerset)
, locator_map =
, coordinates =
, region = South West England
, established_date = Ancient
, established_by =
, preceded_by =
, origin =
, lord_lieutenant_office =Lord Lieutenant of Somerset
, lor ...
-born engineer who had just moved to London.
Easton's firm, inherited by his son James (1796–1871), grew during the nineteenth century to become one of the more important engineering manufacturers in England, with a large works at
Erith
Erith () is an area in south-east London, England, east of Charing Cross. Before the creation of Greater London in 1965, it was in the historical county of Kent. Since 1965 it has formed part of the London Borough of Bexley. It lies nort ...
,
Kent
Kent is a county in South East England and one of the home counties. It borders Greater London to the north-west, Surrey to the west and East Sussex to the south-west, and Essex to the north across the estuary of the River Thames; it faces ...
. They specialised in water supply and
sewerage systems worldwide, as well as land
drainage projects. Eastons had a good business supplying rams for water supply purposes to large
country house
An English country house is a large house or mansion in the English countryside. Such houses were often owned by individuals who also owned a Townhouse (Great Britain), town house. This allowed them to spend time in the country and in the cit ...
s, farms, and village communities. Some of their installations still survived as of 2004, one such example being at the hamlet of
Toller Whelme
Toller Whelme is a small hamlet in Dorset, England, situated in the civil parish of Corscombe approximately east of Beaminster, north of Bridport and north-west of Dorchester. There are seven homes in the hamlet: West Farm, Norcombe Hayes ...
, in
Dorset
Dorset ( ; archaically: Dorsetshire , ) is a county in South West England on the English Channel coast. The ceremonial county comprises the unitary authority areas of Bournemouth, Christchurch and Poole and Dorset. Covering an area of ...
. Until about 1958 when the mains water arrived, the hamlet of
East Dundry just south of
Bristol
Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city i ...
had three working rams – their noisy "thump" every minute or so resonated through the valley night and day: these rams served farms that needed much water for their dairy herds.
The firm closed in 1909, but the ram business was continued by
James R. Easton
James is a common English language surname and given name:
* James (name), the typically masculine first name James
* James (surname), various people with the last name James
James or James City may also refer to:
People
* King James (disambigua ...
. In 1929, it was acquired by Green & Carter of
Winchester,
Hampshire
Hampshire (, ; abbreviated to Hants) is a ceremonial county, ceremonial and non-metropolitan county, non-metropolitan counties of England, county in western South East England on the coast of the English Channel. Home to two major English citi ...
, who were engaged in the manufacturing and installation of
Vulcan and
Vacher Vacher is a surname of French origin. Its literal translation means a keeper of stock or cattle or a herdsman but is generally used by people whose ancestry is traced to the cow-herders. It is also used by a small group of people in India. People wi ...
Rams.
The first US patent was issued to
Joseph Cerneau
Joseph is a common male given name, derived from the Hebrew Yosef (יוֹסֵף). "Joseph" is used, along with "Josef", mostly in English, French and partially German languages. This spelling is also found as a variant in the languages of the mo ...
(or Curneau) and
Stephen (Étienne) S. Hallet (1755-1825) in 1809. US interest in hydraulic rams picked up around 1840, as further patents were issued and domestic companies started offering rams for sale. Toward the end of the 19th century, interest waned as
electricity
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as describ ...
and electric pumps became widely available.
Priestly's Hydraulic Ram
Priestly's Hydraulic Ram, located in Gooding County, Idaho near Hagerman, Idaho, was a hydraulic ram invented and built . It was used to move water uphill to irrigate agricultural land on the plateau above the Snake River. It was located abou ...
, built in 1890 in Idaho, was a "marvelous" invention, apparently independent, which lifted water to provide irrigation. The ram survives and is listed on the U.S.
National Register of Historic Places
The National Register of Historic Places (NRHP) is the United States federal government's official list of districts, sites, buildings, structures and objects deemed worthy of preservation for their historical significance or "great artist ...
.
[ With ]
By the end of the twentieth century, interest in hydraulic rams has revived, due to the needs of
sustainable technology
Environmentally sustainable design (also called environmentally conscious design, eco-design, etc.) is the philosophy of designing physical objects, the built environment, and services to comply with the principles of ecological sustainability ...
in
developing countries
A developing country is a sovereign state with a lesser developed Industrial sector, industrial base and a lower Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is al ...
, and
energy conservation in developed ones. An example is Aid Foundation International in the Philippines, who won an
Ashden Award
Ashden is a London-based charity that works in the field of sustainable energy and development. Its work includes the annual Ashden Awards, advocacy and research in the field of sustainable energy, and mentoring and practical support for award ...
for their work developing ram pumps that could be easily maintained for use in remote villages. The hydraulic ram principle has been used in some proposals for exploiting
wave power, one of which was discussed as long ago as 1931 by
Hanns Günther Walter de Haas (1886–1969), who wrote under the pseudonym Hanns Günther, was a prolific German author, translator, and editor of popular science books.
He began to publish books in 1912, including introductions to topics in electrical engineerin ...
in his book ''In hundert Jahren''.
Some later ram designs in the UK called compound rams were designed to pump treated water using an untreated drive water source, which overcomes some of the problems of having drinking water sourced from an open stream.
In 1996 English engineer Frederick Philip Selwyn patented a more compact hydraulic ram pump where the waste valve used the
venturi effect
The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section (or choke) of a pipe. The Venturi effect is named after its discoverer, the 18th century Italian physicist, Giovanni Battista ...
and was arranged concentrically around the input pipe. Initially patented as a fluid pressure amplifier due to its different design, it is currently sold as the "Papa Pump".
Additionally to this a large scale version named the "Venturo Pump" is also being manufactured by Phil's company.
Construction and principle of operation
A traditional hydraulic ram has only two moving parts, a spring or weight loaded "waste"
valve
A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fitting ...
sometimes known as the "clack" valve and a "delivery"
check valve, making it cheap to build, easy to maintain, and very reliable.
Priestly's Hydraulic Ram
Priestly's Hydraulic Ram, located in Gooding County, Idaho near Hagerman, Idaho, was a hydraulic ram invented and built . It was used to move water uphill to irrigate agricultural land on the plateau above the Snake River. It was located abou ...
, described in detail in the 1947
Encyclopedia Britannica, has no moving parts.
[
]
Sequence of operation
A simplified hydraulic ram is shown in Figure 2. Initially, the waste valve is open (i.e. lowered) because of its own weight, and the delivery valve is closed under the pressure caused by the water column from the outlet The water in the inlet pipe starts to flow under the force of gravity
In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the str ...
and picks up speed and kinetic energy
In physics, the kinetic energy of an object is the energy that it possesses due to its motion.
It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its a ...
until the increasing drag
Drag or The Drag may refer to:
Places
* Drag, Norway, a village in Tysfjord municipality, Nordland, Norway
* ''Drág'', the Hungarian name for Dragu Commune in Sălaj County, Romania
* Drag (Austin, Texas), the portion of Guadalupe Street adj ...
force lifts the waste valve's weight and closes it. The momentum
In Newtonian mechanics, momentum (more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. If is an object's mass ...
of the water flow in the inlet pipe against the now closed waste valve causes a water hammer
Hydraulic shock (colloquial: water hammer; fluid hammer) is a pressure surge or wave caused when a fluid in motion, usually a liquid but sometimes also a gas is forced to stop or change direction suddenly; a momentum change. This phenomenon c ...
that raises the pressure in the pump beyond the pressure caused by the water column pressing down from the outlet. This pressure differential now opens the delivery valve and forces some water to flow into the delivery pipe Because this water is being forced uphill through the delivery pipe farther than it is falling downhill from the source, the flow slows; when the flow reverses, the delivery check valve closes. Meanwhile, the water hammer from the closing of the waste valve also produces a pressure pulse which propagates back up the inlet pipe [Homemade Hydraulic Ram Pump for Livestock Water](_blank)
2 September 2019 ''lgpress.clemson.edu'', accessed 2 December 2022 to the source where it converts to a suction pulse that propagates back down the inlet pipe. This suction pulse, with the weight or spring on the valve, pulls the waste valve back open and allows the process to begin again.
A pressure vessel containing air cushions the hydraulic pressure shock when the waste valve closes, and it also improves the pumping efficiency by allowing a more constant flow through the delivery pipe. Although the pump could in theory work without it, the efficiency would drop drastically and the pump would be subject to extraordinary stresses that could shorten its life considerably. One problem is that the pressurized air will gradually dissolve into the water until none remains. One solution to this problem is to have the air separated from the water by an elastic diaphragm (similar to an expansion tank); however, this solution can be problematic in developing countries where replacements are difficult to procure. Another solution is a snifting valve installed close to the drive side of the delivery valve. This automatically inhales a small amount of air each time the delivery valve shuts and the partial vacuum develops. Another solution is to insert an inner tube of a car or bicycle tire into the pressure vessel with some air in it and the valve closed. This tube is in effect the same as the diaphragm, but it is implemented with more widely available materials. The air in the tube cushions the shock of the water the same as the air in other configurations does.
Efficiency
A typical energy efficiency is 60%, but up to 80% is possible. This should not be confused with the volumetric efficiency, which relates the volume of water delivered to total water taken from the source. The portion of water available at the delivery pipe will be reduced by the ratio of the delivery head to the supply head. Thus if the source is 2 meters above the ram and the water is lifted to 10 meters above the ram, only 20% of the supplied water can be available, the other 80% being spilled via the waste valve. These ratios assume 100% energy efficiency. Actual water delivered will be further reduced by the energy efficiency factor. In the above example, if the energy efficiency is 70%, the water delivered will be 70% of 20%, i.e. 14%. Assuming a 2-to-1 supply-head-to-delivery-head ratio and 70% efficiency, the delivered water would be 70% of 50%, i.e. 35%. Very high ratios of delivery to supply head usually result in lowered energy efficiency. Suppliers of rams often provide tables giving expected volume ratios based on actual tests.
Drive and delivery pipe design
Since both efficiency and reliable cycling depend on water hammer effects, the drive pipe design is important. It should be between 3 and 7 times longer than the vertical distance between the source and the ram. Commercial rams may have an input fitting designed to accommodate this optimum slope
In mathematics, the slope or gradient of a line is a number that describes both the ''direction'' and the ''steepness'' of the line. Slope is often denoted by the letter ''m''; there is no clear answer to the question why the letter ''m'' is used ...
. The diameter of the supply pipe would normally match the diameter of the input fitting on the ram, which in turn is based on its pumping capacity. The drive pipe should be of constant diameter and material, and should be as straight as possible. Where bends are necessary, they should be smooth, large diameter curves. Even a large spiral is allowed, but elbows are to be avoided. PVC will work in some installations, but steel pipe is preferred, although much more expensive. If valves are used they should be a free flow type such as a ball valve or gate valve.
The delivery pipe is much less critical since the pressure vessel prevents water hammer effects from traveling up it. Its overall design would be determined by the allowable pressure drop based on the expected flow. Typically the pipe size will be about half that of the supply pipe, but for very long runs a larger size may be indicated. PVC pipe and any necessary valves are not a problem.
Starting operation
A ram newly placed into operation or which has stopped cycling should start automatically if the waste valve weight or spring pressure is adjusted correctly, but it can be restarted as follows: If the waste valve is in the raised (closed) position, it must be pushed down manually into the open position and released. If the flow is sufficient, it will then cycle at least once. If it does not continue to cycle, it must be pushed down repeatedly until it cycles continuously on its own, usually after three or four manual cycles. If the ram stops with the waste valve in the down (open) position it must be lifted manually and kept up for as long as necessary for the supply pipe to fill with water and for any air bubbles to travel up the pipe to the source. This may take some time, depending on supply pipe length and diameter. Then it can be started manually by pushing it down a few times as described above. Having a valve on the delivery pipe at the ram makes starting easier. Closing the valve until the ram starts cycling, then gradually opening it to fill the delivery pipe. If opened too quickly it will stop the cycle. Once the delivery pipe is full the valve can be left open.
Common operational problems
Failure to deliver sufficient water may be due to improper adjustment of the waste valve, having too little air in the pressure vessel, or simply attempting to raise the water higher than the level of which the ram is capable.
The ram may be damaged by freezing in winter, or loss of air in the pressure vessel leading to excess stress on the ram parts. These failures will require welding or other repair methods and perhaps parts replacement.
It is not uncommon for an operating ram to require occasional restarts. The cycling may stop due to poor adjustment of the waste valve, or insufficient water flow at the source. Air can enter if the supply water level is not at least a few inches above the input end of the supply pipe. Other problems are blockage of the valves with debris, or improper installation, such as using a supply pipe of non-uniform diameter or material, having sharp bends or a rough interior, or one that is too long or short for the drop, or is made of an insufficiently rigid material. A PVC supply pipe will work in some installations but a steel pipe is better.
See also
* Boost converter - electronic–hydraulic analog of the hydraulic ram.
* Pulser pump, a similar device made from a trompe
A trompe is a water-powered air compressor, commonly used before the advent of the electric-powered compressor. A trompe is somewhat like an airlift pump working in reverse.
Trompes were used to provide compressed air for bloomery furnace ...
connected to an airlift pump
* Heron's fountain
* Water rocket
References
Further reading
*
*
*
*
*
*
External links
Ram pump complete blueprints
{{Authority control
Articles containing video clips
*
Liquid-piston pumps
Pumps
Water
French inventions
it:Pompa fluidodinamica#Pompa ad ariete idraulico