Water Pump Technology
Pond near African Village
Water Pump Technology
Pond
Water Pump Technology
Pond
Water Pump Technology
Pond near African Village
Hydraram
Manufactured since the 1880s, the hydraulic ram pump (“Hydraram”) utilizes a “water hammer” shock
wave concept. Water has weight, so a volume of water moving at a certain speed has momentum – it
doesn't want to stop immediately. If a car runs into a brick wall the result is crumpled metal. If a moving
water flow in a pipe encounters a suddenly closed valve, a pressure “spike” or increase suddenly appears
due to all the water being stopped abruptly (that's what water hammer is – the pressure spike). If you turn
a faucet or hydrant off in your house quickly, you may hear a small “thump” in the pipes. That's water
hammer.
Typically, 3 feet to 10 feet of lift develops for every 1 foot of elevation drop from the water inlet to the
pump. However, the ram is quite inefficient. Usually 8 gallons of water must pass through the waste valve
for each 1 gallon of water pumped by the ram. That is acceptable for a creek or river situation, but may not
be a good option for a pond that does not have a good spring flow. The following six steps describe in
layman's terms a complete cycle of a hydraulic ram pump. Pressure wave theory will explain the technical
details of why a hydraulic ram pump works.
Water Pumping Technology
Rope and Washer
Water (blue arrows) starts flowing through the drive pipe and out of the “waste” valve (4 on diagram),
which is open initially. Water flows faster and faster through the pipe and out of the valve.
[3]
At some point, water is moving so quickly through the “waste” valve (4) that it grabs the
swing check's flapper, pulling it up and slamming it shut. The water in the pipe is moving
quickly and doesn't want to stop. All that water weight and momentum is stopped, though,
by the valve slamming shut. That makes a high pressure spike (red arrows) at the closed
valve. The high pressure spike forces some water (blue arrows) through the spring check
valve (5) and into the pressure chamber. This increases the pressure in that chamber
slightly. The pressure “spike” the pipe has nowhere else to go, so it begins moving away
from the waste valve and back up the pipe (red arrows). It actually generates a very small
velocity *backward* in the pipe.
As the pressure wave or spike (red arrows) moves back up the pipe, it creates a lower
pressure situation (green arrows) at the waste valve. The spring-loaded check valve (5)
closes as the pressure drops, retaining the pressure in the pressure chamber.
At some point this pressure (green arrows) becomes low enough that the flapper in the
waste valve (4) falls back down, opening the waste valve again.
Most of the water hammer high pressure shock wave (red arrows) will release at the
drive pipe inlet, which is open to the source water body. Some small portion may travel
back down the drive pipe, but in any case after the shock wave has released, pressure
begins to build again at the waste valve (4) simply due to the elevation of the source
water above the ram, and water begins to flow toward the hydraulic ram again.
Step 6
Water begins to flow out of the waste valve (4), and the process starts over once again.
World Health Organization Global Health Observatory—
2012 [2]
• Over 2 billion people gained access to improved water sources and 1.8 billion people gained
access to improved sanitation facilities between 1990 and 2010
• As of 2010, 783 million people still rely on unimproved water sources (surface water from lakes,
rivers, dams, or unprotected dug wells or springs) for their drinking, cooking, bathing and other
domestic activities.
• Over 780 million people are still without access to improved sources of drinking water and 2.5
billion lack improved sanitation. If current trends continue, these numbers will remain
unacceptably high in 2015: 605 million people will be without an improved drinking water
source and 2.4 billion people will lack access to improved sanitation facilities.
• The proportion of the world’s population with access to improved drinking water sources
increased from 76% to 89% globally between 1990 and 2010. While coverage is above 90% in
Latin America and the Caribbean, Northern Africa and large parts of Asia, it is only 61 per cent
in sub-Saharan Africa. There are also disparities between urban and rural coverage, where an
estimated 96% of the urban population globally used an improved water supply source in 2010,
compared to 81% of the rural population.
United Nations Water and Sanitation Fact Sheet—June
2012 [1]
• Freshwater is also an essential input to agriculture and the production of energy, and a lack of
sufficient water to meet all needs has huge implications for development — for jobs, health
and food security. Currently, 80 per cent of the world’s population lives in areas with high
levels of threat to water security. The most severe threats affect 3.4 billion people, almost all
in developing countries.
• Over 80 per cent of wastewater worldwide is not collected or treated.
• Today, 1.6 billion people live in regions with absolute water scarcity. By 2025, two-thirds of the
world’s population may be affected by water stress conditions.
• 828 million people live in slum conditions, lacking basic services such as drinking water and
sanitation.
• This number is increasing by 6 million each year and will hit a total of 889 million by 2020.
References:
[1] United Nations Department of Public Information, June 2012. The Future We Want: Water and Sanitation.
http://www.un.org/en/sustainablefuture/pdf/Rio+20_FS_Water.pdf
[2] World Health Organization, Global Health Observatory, 2012. Use of Improved Drinking Water Sources.
http://www.who.int/gho/mdg/environmental_sustainability/water_text/en/index.html
[3] Voss Foundation, November 24, 2010. The Technology of a Rope and Washer Pump
http://www.thevossfoundation.org/News/Entries/2010/11/24_The_technology_of_a_rope_and_washer_pump.htm
l
[4] United Nations Environment Programme. Newsletter and Technical Publications: Rope-washer Pump.
http://www.unep.or.jp/ietc/publications/techpublications/techpub-8a/rope.asp
[5] Clemson Cooperative Extension, May 2012. Home-made Hydraulic Ramp Pump.
http://www.clemson.edu/irrig/equip/ram.htm
The concept behind the rope and washer
system is to use readily available materials
to easily create a pumping system for
consumer use. This human powered
system is largely used in Kenya, Zimbabwe,
and Burkina Faso (United Nations
Environmental Programme U.N.E.P. [4])
• Essentially, the washers are threaded
through the rope and allowed to pass
through a PVC pipe that tightly
surrounds the washers.
• While the washers are being pulled
through the system, they are forcing
water up the pipe and out into the
reservoir.
• As seen in the picture below, the system
can be expanded to help irrigate crops.
Pros:
• The system does not require any valves or
complex bearings.
• Easy to manufacture with local resources. The
U.N.E.P. estimates that the pump costs between
$30 to $50 to construct and install.
• Ease of use
• Possible use in agricultural irrigation.
Cons:
• The system has poor pumping efficiency because
water is allowed to leak through the pipes
[4]
Water-Delivery System
While simply having access to water is a problem for some people in developing countries, others
face the difficulty of transporting water from its source to their homes or fields. The path may be
long, steep, or a combination of both. The operational water delivery system on display here solves
the problem of transporting water to the top of steep hillsides by means of an electric water pump
and PVC piping. Flowing along the base of the hill to the west of the African village is a creek in
which a Flotec® submersible well pump (pictured below) is positioned.
Outlet
Pedal-Pump
Essentially, the human-powered pump forces water from the lower elevation and pushes to a higher
plane. The inlet uses suction pressure to pull the water up through the pipe. The water then passes
through a check valve which prevents it from dropping back down the inlet pipe. Then, pressure
continues to build up in the system and the water is forced through the outlet and up the remaining
elevation.
Pros:
• Cost-efficient. The pumps are being sold for $100 by Kickstart
• Light-weight and maneuverable
• Durable
• Helps increase crop yield and produce by allowing crops to grow year round.
Cons:
• Low pumping efficiency.
Inlet
[3]
Visualize the pump containing an electric motor in the bottom half of the cylinder which drives a
screw or auger in the top half of the cylinder. The rotating action of the screw creates a suction
drawing water in the inlet and pumping it out the outlet. The concept of pumping water with a
screw is shown below.
[2]
[1]
[4]
The outlet of the pump is connected to approximately 800 feet of white PVC pipe (comprised of 20-foot
sections joined together). Gaining about 200 feet in elevation, this network of piping traverses the
hillside from the creek bank to the top of the hill. Five car batteries provide power to the pump via
wiring threaded through gray PVC pipe that runs alongside the water delivery PVC pipe. Ideally, this
water delivery system would be used to fill the tank atop the water tower for irrigation of the garden
each day.
References:
[1] Central America, 2010. Achieve the Unachievable.
http://innovateca.files.wordpress.com/2007/02/pump_manual.gif
[2] Kickstart, January 2009. Helping Small Scale Farmers: Out of Poverty.
http://www.kickstart.org/news/KickStart_B2B_BrochureJan09.pdf
[3] Flotec, 2012. 2-Wire 4 Inch Submersible Well Pump, 115 Volts 1/2 HP
http://www.flotecpump.com/ResidentialProduct_fl_hw_4S_FP2211.aspx
[4] Clip Art, 2012. Archimedean Screw.
http://etc.usf.edu/clipart/15000/15042/archimedean_15042_lg.gif
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