Dhone
The dhone consists of a trough made from a wooden log or iron sheet; closed at one end and open at the other. The trough is mounted on a suspended pivoted lever to produce a see-sawing gutter or dhone which operates at relatively low lifts of up to 1.5 m.
The trough is lowered into the water by exerting pressure using a rope or the foot of the operator until the closed end is submerged in water. Upon releasing pressure the trough comes to its original position and the water is delivered to the irrigation channel. Typical yields of 80-160 l/min can be obtained from the dhone between 0.3-1.0 m.
This device uses flap valves and can be operated by a single person shifting the weight back and forth at the fulcrum. 1
Contents
Suitable conditions
The Dhone is used in Bangladesh.
It is also widely used (probably in the region of one million) along the Ganges and Brahmaputra rivers in the Indian sub-continent.
The Dhone is a great improvement to the swing basket, as it only needs one person to operate, and can move more water, more quickly. It is a little more expensive than a swing basket, but considering it frees up a laborer and moves more water, it is still very cheap compared to other water lifting devices.
| Advantages | Disadvantages |
|---|---|
| - A relatively inexpensive traditional technology which can be locally made and maintained - Easy to operate |
- Limited to lifts of less than 1.5 m - Low to medium efficiency (20-50%) |
Field experiences
A single dhone will lift 7.5 litre/sec at a lift of 0.75m (115gall/min at 30 inches), which reduces to about 2 litre/sec (30 gall/min) at 1.5m (or 60inches) head. Therefore the dhone will move more than twice as much water as a swingbasket at low lifts, moreover using the power of only one person rather than two. Many Bangladesh farmers try and use a single stage dhone at an overly high lift, and lose a lot of performance as a result; the optimum lift per stage is approximately 1m (40in). 2
Manuals, videos, and links
References
- ↑ Food from Dryland Gardens - An Ecological, Nutritional, and Social Approach to Small-Scale Household Food Production (CPFE, 1991).
- ↑ Water Lifting Devices. FAO, 1986.
Acknowledgements
- Jane Olley, HUMAN & ANIMAL POWERED WATER-LIFTING DEVICES FOR IRRIGATION. Practical Action, November 2008.
