A pump developed at the beginning of the industrial revolution has been combined with modern solar power technology to help subsistence farmers in sub-Saharan Africa irrigate their fields.
Increasing soil moisture levels through irrigation can lead to substantial increases in agricultural productivity, but most smallholder farmers in Africa do not have enough money to buy expensive equipment.
The system, being developed by product design engineering agency the Imagination Factory as part of an InnovateUK-funded competition for the Department for International Development, is designed to pump up to six tonnes of water per day, while requiring very little operation or maintenance.
The device, which under the terms of the competition must have a production cost of no more than £30 per unit, is based on a steam-powered pump, according to Julian Swan, co-founder of the Imagination Factory.
“The pump dates back to the very beginning of steam engines, the Thomas Savery pump, developed at the beginning of the industrial revolution, and patented in 1698,” said Swan. “It has no moving parts other than a ball valve, no pistons, no seals, and is very simple.”
A solar collector directs heat from the sun onto an absorber tube containing water, to produce steam.
The device then uses this steam to positively displace the water inside the pump chamber, said Swan. “It then relies on the steam collapsing and condensing to create a hard vacuum, and that then sucks water back into the pump chamber.”
To develop the design, the team scoured the library and collection of the London Museum of Water and Steam, including 100 year-old textbooks and instruction manuals, in a bid to understand how the pumps originally worked.
“There are no design guides, so it was a case of going through the archives, trying to measure off engravings to work out what the geometries of the pump chamber were,” said Swan.
The team completed the feasibility stage of the programme, in which they built a proof of concept rig, and were then chosen to take their design on to the next stage of the competition. They are now developing the concept into a demonstrator system.
They hope to begin testing the pump in a country in sub-Saharan Africa next year.
testing the pump in a country in sub-Saharan Africa next year. ….but most smallholder farmers in Africa do not have enough money to buy expensive equipment…..
But they can somehow find the money (or at least their political leaders?can) to purchase weapons and their means of delivery and to engage in the most horrible of wars! civil ones!
Actually, no need to go to Subsaharan places for tests: various military establishments and firms supplying such have excellent facilities allowing the test of weapons, protective items, life support systems, lubricants, in all aspects of climate, weather, and so on. Why not use these.
I am reminded of a lovely comment from Dr Strangelove: when two ambassadors (US and USSR) are squaring up for fisticuffs “You can’t fight in here, this is the war room!”
“Imagination Factory”.
These items can be purchased of the shelf, 20 years ago I utilised Armstrong and Spirex Sarco products, others are available. They are usually called Pumping Traps, Pressure Powered Pumps, Steam Operated Condensate return Pump, Mechanical Pump Trap Operation, etc depending on manufacturer. They can be operated by steam or any pressurised gas.
In a Utility room, no suitable electricity supply was available for a pump, but a supply steam was being used to heat a calorifier – a hot water tank with a heating coil. The desired temperature was approximately 60ºC sometimes 70º. A steam supply was fed to a temperature control valve with a steam trap on the exit of the heating pipe leaving the tank. Severe water hammer was experienced on commisioning. I was called.
The steam was condensing on the water coils at approximately 60ºC, therefore the pressure of the steam in the coils was between 0.1 & 0.3 bar. See Steam Tables, steam pressures are below atmospheric for steam at temperatures below 100ºC – Newcomen Engine.
Therefore the condensate in the coils was less than atmospheric pressure, the condensate couldn’t escape by gravity. Only when the whole heating pipe saturated (full) of water could the steam pressure push the condensate out of the steam trap with positive pressure. But steam in direct contact with water under pressure causes water hammer, explosive collapse of steam bubbles.
The pumping trap solved the problem perfectly by pumping the condensate under partial vacuum into a positive pressure condensate header (return pipe). Water hammer disappeared because condensate drained into trap at the same pressure (partial vacuum) as the steam. I had planned to use a pumping trap to remove continually running sample water from a water purification plant that fed the boiler within a chemical plant, I retired before I could implement it as a simple water pump driven by 2.75 bar steam (40psi)
What seriously worries me is the £30 price tag, I have seen Indian fake copies of steam traps decades ago. Just look back into the Engineer Magazine’s Archives and Steam and Pressure explosions KILLED people. The Imagination Factory must not only reinvent an existing product, but they MUST ensure their product is SAFE. Steam burns are very serious, especially with shrapnel from exploding steam systems and in combination can & have been fatal. Please get the Engineering of this proposed steam system correct, we have the experience within existing product suppliers and Professional Engineers.