China
Africa
Explore chapters and articles related to this topic
Hydro Power
Published in Sergio C. Capareda, Introduction to Renewable Energy Conversions, 2019
A hydraulic ram has two major parts: the waste valve and the delivery valve. The waste valve, also known as the “clack” valve because of the sound it makes, is either spring-loaded or weight-loaded. Through the delivery valve, water is conveyed from its source to a much higher elevation. Hydraulic rams are cheap to build, easy to maintain, and quite reliable. The basic components are the following: Inlet drive pipeOutlet delivery pipeWaste valveDelivery check valvePressure vessel
Rural water supply
Published in Sandy Cairncross, Richard Feachem, Environmental Health Engineering in the Tropics, 2018
Sandy Cairncross, Richard Feachem
Two other types of pump, the hydraulic ram and the solar pump, use naturally occurring sources of energy. A hydraulic ram uses the energy of flow of a large volume of water, to pump a small proportion of that volume. It therefore requires a much larger flow of water of suitable quality than would be necessary for the community’s needs alone. It also requires careful adjustment (Watt 1975). Solar pumps are suitable for arid areas, they can pump as much as 10 l/s, but they involve sophisticated technology. The panels need to be kept very clean and free of dust if they are to function efficiently; not an easy task in arid areas. Many have been installed, with mixed results, particularly in francophone West Africa and in Somalia. Theft of solar panels and lack of local skills for proper installation and repair can be a problem. Solar pumps also need storage tanks to cope with reduced pumping on overcast days.
Positive Displacement Pumps
Published in Hauser Barbara A., Practical Hydraulics Handbook, 2017
Hydraulic Ram: The ram lifts water by utilizing the impulse developed when a moving mass of water is suddenly stopped. In other words, it makes use of the pressure created by water hammer. Not an efficient pumping mechanism, a relatively large amount of water must be available at moderate head in order to move a small amount of water to higher head. Water flows from a reservoir to a valve box below, and on out of the box through a waste valve. If that valve is suddenly closed, water hammer pressures develop, which open another valve into a vertical delivery pipe, and some water passes up the pipe. As negative pressure waves return, the delivery pipe valves closes, and water continues on through the box. What keeps it going is the water flow through the waste valve. When well established, it provides enough force to shut the waste valve, starting a new cycle. The hydraulic ram is not really a pump - just a set of valves.
Interpreting the results of in situ pull tests on Friction Rock Stabilizers (FRS)
Published in Mining Technology, 2018
Luke Nicholson, John Hadjigeorgiou
Figure 5 shows a typical apparatus used for manually logged pull testing. A bolt extension, also known as a pulling rod, comprised of a thick, threaded steel bar is attached to the test bolt with a thread adaptor. A loading frame is mounted and made flush with the rock, if necessary by inserting plates between the rock and the loading frame (certain frames have adjustable legs to perform this task). This may also orient the apparatus so as to apply load along the bolt’s axis. A hydraulic ram is then mounted on the assembly adjacent to the loading frame, followed by a wing nut to secure the system and transfer load from the ram to the pulling rod and rock bolt. A Vernier caliper with an electronic display is affixed to the apparatus, which measures the relative displacement between the bolt extension and the loading frame. Load is applied by pressurising the hydraulic ram with a hand pump and measured by a calibrated pressure gauge. A ‘pre-load’, typically 2 tons (17.8 kN), may be applied to tighten the system and underlying rock mass and/or surface support before recording of displacement begins. Measurements are made by reading displacement off of the Vernier caliper at predetermined load intervals. Intervals are typically 1 ton (8.9 kN), but may be 0.5 tons (4.5 kN) or 2 tons (17.9 kN) depending on the preferences of the testing personnel and reinforcement element being tested. Testing for most types of rock bolt is generally performed until the bolt reaches its working capacity (‘the load on the anchor system at which significantly increasing displacement begins’, which may be indicative of yield for some reinforcement elements; ASTM D4435 2013). An FRS is generally loaded until it slips (i.e. its ultimate capacity), although in many cases displacement is not recorded.
Making Practices in Pursuit of Ecological Ethos: Learnings from Three Ecovillages in Australia
Published in International Journal of Human–Computer Interaction, 2023
Participants try to grow as much food as possible to minimise their environmental footprint in all ecovillages. We can witness people’s interaction with the local environment in edible gardens. For example, the garden in EV2 is located on a slope. P10 designs the swale along the contour to slow rain flow and stop minerals from draining away. Instead of the traditional method of digging dams to store water, the swale is a more efficient way to capture water and prevent it from evaporating. He also installed a swivel pipe to control the water level of the swale when it rains heavily. They aim to create a forest majoring in food plants that build topsoil. The by-product is that the forest feeds residents. EV2 was a cow paddock before 2008. There is now a forest here after 13 years of planting because it is being restored as an ecosystem. In his view, the strategy of sustainability is syntropic farming, planting nuts and fruits of deep roots, long-lived trees. Trees like avocados, nuts, and olive trees can live hundreds of years. P10 comments that syntropic farming is an example that provides high-value nutrition, and produces more topsoil and biomass with little labour: I became fascinated with growing food and the link between food and mental health and well-being. And the more I studied that, and the more I realized that mainstream production of the city is releasing carbon and destroying the atmosphere. They require a forest. Trees sequester carbon. Something a pin dropped to me that this was a holistic solution. It turns out that truly healthy food, what truly healthy food with low food miles, is not just good for us. It’s good for the planet. So the goal is to produce topsoil. We want to get a forest majoring in food plants. So the by-product is that the forest feeds us. If the goal is to grow food, you will knock down a forest to put in a row of quick cash crops to get money and food quickly. But that drives an ecosystem back into entropy. Decay and break down. A forest is syntropic. Every day. What’s in front of us? Here we have more biomass, more oxygen, more topsoil, no labour. (Figure 8) P10 also introduces the ram pump he made in the garden. Ram pump or hydraulic ram can often be seen in remote and off-the-grid contexts. It can pump water just using water kinetic energy without any outside power. In other words, it uses water to pump water. P10 believes the ram pump he uses can run for more than 50 years without service. The water comes down with velocity and drives the ram pump. Half the water comes out, used for irrigation, while the other half is driven up higher than the source, where they store it in a tank. In his opinion, it is a perfect example of sustainable technology, which is simple, long-lasting, and not about planned obsolescence (Figure 9).