Many crops especially rice, need stagnant and copious supply of water for a good yield and the river ayacuts in India have been well developed for a perennial flow of water atleast during the crop season. Irrigation plays a vital role in agriculture as a leading input both directly and indirectly because the cost of other inputs like fertilizer etc. largely depend on the availability of ensured water supply in the fields.
In the Indian context, capital intensive technologies like tubewells are usually beyond the purchasing capacity of the poor farmers. Labour intensive technologies such as pedal pumps, hand pumps, rower pumps, treadle pumps, Archimedean screw pump etc. are within the reach of the poor farmer due to their lower initial and operating cost.
A Bicycle Operated Low Head Water Pump designed, fabricated and tested in this project utilizes an improvised gear bicycle with chain and sprocket drive, a scooping mechanism, pipes and related pipelines.
The device is placed near a water source and the bicycle is pedalled. Due to this rotary motion, the scooping mechanism (connected to the wheel which is chain driven) scoops water from the water source and the collected water is sent to the farmlands through pipelines.
The whole device is non-polluting and totally independent of fuel, sunlight, wind etc.. Another attractive feature of this design is that the whole machine can be detached from the common bicycle, transported to the field and erected in situ.
Suitable modifications have been done to the bicycle to facilitate the transmission of motion from the rear wheel of the bicycle to the spiral scooping mechanism attached to a separate rim. A frame has been fabricated and fixed on the hub of the rear wheel so as to lift it off from the ground and thus avoid any hindrance when the bicycle is pedalled.
The whole setup is placed either in a stream or a stagnant water source like the village tank and the bicycle is pedalled. The scooping mechanism scoops the water which is now supplied to the fields with the help of delivery pipes. The designed model has a flow rate of 240 litres/hourand a head between 0.5metres and 1.5 metres. The stresses in the various members have been calculated and the factors of safety have been found to be satisfactory.
This flow rate can be increased with addition of more scoops and spirals and also by redesigning the scoop with an elliptical cross section instead of the present conical funnel. These twin changes will, in addition to increasing the flow rate by a factor of probably ten, will ensure a more uniform load torque and hence ease of operation for the worker.
The next prototype can be designed with a much larger wheel and/or a set of wheels than in the present model. One can also imagine a tandem bicycle operable by two or more workers at a time.
It is hoped that the present Bicycle Driven Low-Head Water Pump project is another step in today’s urgent search for an energy efficient, low cost, easily maintainable, non-polluting and affordable water pump to meet the irrigation needs of the small farmer in the developing world especially since agriculture all over the world is a loss making sector and depends heavily on government subsidy.