Tropical Agricultural Research Vol. 4 1992 Identification of a Manually Operated Water Lifting Device for Small Scale Cash Crop Growers in the Dry Zone C.L. Rajapakse and B:F.A. Basnayake 1 Postgraduate Institute of Agriculture University of Peradeniya Peradeniya ABSTRACT. Ait appropriate water lifting device had been a long felt need in the dry zone for small scale cash crop growers. Due to escalating prices of fuel and motorized pumps, attention was focused on a machine which could operate with renewable sources of power. Two surveys, one on small scale dry zone fanners and the other on available water lifting devices were carried out to ascertain the appropriate device required for use under the prevailing dry zone fanning conditions. A simple manually operated water lifting device was decided upon after studying the capabilities of the existing manually operated water lifting devices in use. Tlie Chinese Chain and Washer pump proved to be a promising implement. A further step forward would be an animal drawn version of this unit. Two operators using this machine could achieve a delivery of about 10 m 3 / f t over a head of about 6 m while only about 1.2 in 3 / f t could be achieved by using the same man power with the rope and bucket. On the basis of the above output it has a potential of irrigating about 0.4 ha (1 ac) of land depending on the crop and field conditions, INTRODUCTION This study is mainly concerned with farmers who have their own wells and limited arable lands below one acre in close proximity to these wells. They are unable to establish any kind of crop satisfactorily without proper irrigation. They need a low cost system to lift water from their wells to irrigate the land. These farmers have limited labour and lifting water manually from a well with rope and bucket to irrigate Department of Agricultural Engineering. Faculty of Agriculture. University of Peradeniya. Tropical Agricultural Research Vol. 4 1992 about one acre of f a r m - l a n d is a difficult task (Farrington, el al, 1980; Silva et. al, 1982). In most cases, a power operated pump is beyond the means of an ordinary farmer. For example, a centrifugal pump with an inlet port of 50 mm (2") diameter manufactured in Sri Lanka was about Rs. 5000.00 in 1980; it is now sold al about Rs. 15,000.00. It is therefore more appropriate lo have a simple, low cosl, manually operated water pump which could serve ihe purpose. Objectives of the study a. To conduct a literature survey on available water lifting techniques and a field survey to find the present practices in lifting water by- small scale farmers, available resources and field problems. b. To select a manually operated water lifting device which suit the needs of the small scale farmers. MATERIALS A N D M E T H O D S Information gathered from the literature survey and from the field survey were matched to select the most appropriate device. The following factors were considered in different water lifting devices and with the farmers in view- Factors considered in different water lifting devices: a. Construction b . Head range c. Power range d. Output e. Efficiency f. Cost g. Suitability for irrigalion h. Possibility of harnessing animal power 316 Tropical Agricultural Research Vol. 4 1992 Selection procedure Of the factors mentioned above in view of the farmers, some are independent variables which are beyond the farmers' control (eg. depth of water available etc.), and some are interrelated with high variability. For instance, if the power available and the area to be cultivated are constant, the fanner has to adjust the time spent for irrigation. If there is any difficulty in spending more time in order to maintain the water requirement, either the extent of cultivation or the power input has to be adjusted accordingly. Since the variability is very high it is quite difficult to make a decision as to what pump should be selected. Therefore, the most convenient method of selection would be to bear in mind the worst conditions that could prevail in the study areas and to choose one or two pumps which could continue to work under such conditions. Once the preliminary selection is done, the remaining or the less important factors could be considered to make the final selection. RESULTS A N D DISCUSSION In order to make the preliminary selection, the two most important factors, namely the depth of water and the available power were considered (i.e. 7 m depth and 0.12 kW power). From the figures 1, 2, 3 if the area demarcated above the 6 m (head) line and below the 0.125 kW (power) line were observed assuming two operators could be employed to operate the device. Chain and Washer pumps, Centrifugal pumps, Persian Wheel and Noria, Diaphragm pumps, and Piston pumps 317 Factors considered with the farmers in view: a. Presently adopted methods to lift water and reasons for their use b . Available sources of water and their potential c. Potential land available and area allocated for cultivation d. Types of crop cultivated e. Irrigation requirements f. Availability of labour and probable cost g. Availability of draught animals h. Financial position of farmers i. Choice of adopting new technology to improve their present farming condition Tropieai Agricultural Research Vol. 4 1992 DISCHARGE Figure 1. Typical head and discharge capacities for different types of pumps and water - lifting devices on a log-log scale CFraenkeL 1986V 318 Tropical Agricultural Research Vol. 4 1992 i t DISCHARGn Figure 2. Typical head and discharge capacities for different types of pumps and water-lifting devices on a log-log scale (Continued). 319 Tropical Agricultural Research Vol. 4 1992 DISCHARGE Figure 3. Typical head and discharge capacities for different types of pumps and water - lifting devices on a log-log scale (Continued). 320 Tropical Agricultural Research Vol. 4 1992 are included within the area. From these selected devices, Centrifugal pumps, Persian Wheel and Noria could be dropped, since normally they are not powered by humans. Finally, the selection was simplified and reduced to two devices — Chain and Washer pumps and Piston pumps (Twin Treadle pump). The Table 1 indicates .pump characteristics of these two types of pumps. However Diaphragm pumps were eliminated due to their relatively low efficiency, dependability on specialized spare parts which cannot easily be improvised in the field and very high operating forces. Table 1. Review of pumps and water lifts Pump Head Input Flow Efficiency Range Power Range (m) (kW) ( m 3 / h ) (%) Chain and Washer pump 5 - 2 0 0 . 0 2 - 1 5 - 3 0 5 0 - 8 0 Treadle pump 1 - 7 0.05 - 0.1 3 - 7 40 - 85 Source: Fraenkel, (1986); Stickney, (1985). Selection was done by analyzing the performance of two mechanisms (Chain and Washer pump and Treadle pump, sec figures 4 and 5) more closely when they were lifting water at a depth of 6 m below ground level using only 0.125 kW of power. If these pumps are operated under the conditions described earlier, the power input would be 0.125 kW, the total irrigation requirement would be 10 mm/day the depth of water as 6 m and the time spent to pump water as 4 hours. It can be calculated that the area that could be irrigated is about 0.4 ha and 0.29 ha for the Chain and Washer pump and Treadle pump respectively (Carruthers, 1985). The respective discharge rates are 10 m 3 / h a n d 7.2 m 3 / h . Under the above conditions the Chain and Washer pump showed much better promise than the other (exceptionally good discharge rate). Tropical Agricultural Research Vol. 4 1992 Water level L A V Maximum lifting head 6m Diameter of well: Js 0.08m Dischargerate: 8.6m 3/hr Rotational speed: 34rpm Efficiency: 76% Number of persons required: 1 - 2 Figure 4. Chinese Liberation Chain and Washer pump (Fraenkel 1986, Watt 1977) 322 Tropical Agricultural Research Vol. 4 1992 Figure 5. Sketch of a Twin Treadle pump (Trasp 1989) 323 Tropical Agricultural Research Vol. 4 1992 CONCLUSION The Chain and Washer pump appeared to be a better solution. This choice is made especially because of its assumed low maintenance cost in comparison to the other two pumps, durable and ergonomic design, high efficiency and prospects for introducing an animal drawn version (Shoufan et ai, 1982; Stern, 1979). Although at this point it is beyond the objectives of this study, if an animal drawn version is introduced (since there are plenty of draught animals in most of the areas) the operating costs would be minimal. Further, when power input is high, water could be pumped from even deeper wells and a greater yield could also be expected by using larger working pipes (Breuer and Netzband, 1980; Darrow and Saxcnian 1986; Heber, 1978; Rushan and Zhongde, 1979) A C K N O W L E D G E M E N T I wish to record my appreciation and extend my sincere thanks to my Supervisors at the Department of Agricultural Engineering, Faculty of Agriculture, University of Peradeniya respectively for their invaluable advice and guidance. I gratefully acknowledge the generous financial assistance given me by the West German Governments Agency for Technical C o - o p e r a t i o n (GTZ) and the unstinted support given by G T Z team. My special thanks are also due to the Agricultural Development Authority for proposing this study, and all farmers and others who assisted me in carrying out the field survey. I am also grateful to all members working in the Farm Mechanization Research Center for encouraging me continuously and rendering their services without reservation until the project was completed. 324 Tropical Agricultural Research Vol. 4 1992 R E F E R E N C E S Breuer, A. and Netzband. A. (1980). Small - Scale - Irrigation. German Appropriate Technology. Exchange (GATE) . Deutsche Gesellschafl fur Technische Zusammenarbeit (GTZ), Eschborn, Germany. Carruthers, J. (1985). Tools for Agriculture. A Buyer's Guide to Appropriate Equipment, Intermediate Technology Publication in association with G T Z / G A T E , London, UK. Darrow, K. and Saxenian, M. (1986). Appropriate Technology Source book. A guide to practical books for village and small community technology, Revised and Enlarged Edition, A Volunteers in Asia Publication. Farrington, J., Abeyratne, F., Ryan, M. and Bandara, S. (1980). Farm Power and Water Use in the Dry Zone Part I and II. Fraenkel, P.L. (1986). Water lifting devices. Irrigation and Drainage paper No.24, FAO, Rome, Italy. Heber, G. (1978). Water pumping systems using renewable energies. German Appropriate Technology Exchange (GATE) , Deutsche Gesellschaft fur Technische Zusammenarbeit (GTZ) , Eschborn, Germany. Rushan, G. and Zhongde, Z, (1979). On the Development of Human, Animal, Wind and Water Power Lifting Devices for Irrigation and Drainage in China, Ministry of Water Conservancy, Beijing, China. Silva, A.T.M., Devendra, T.O. and Gunasekara, W. (1982). The Study of Lift - Irrigated Agriculture in Sri Lanka. Marga Institute, Sri Lanka. Schoufan, G; Jiangua, Y. and Zuxxun,. C. (1982). T u b e - C h a i n Waterwheel, Proceedings U N D P / F A O China workshop of November, FAO, Rome, Italy. Stern, P.S. (1979). Small Scale Irrigation. Intermediate Technology Publications, London, England. 325 Tropical Agricultural Research Vol. 4 1992 Stickney, R.E., Piamonte, V., de Sagun, Q. and Ventura, I. (1985). Human - Powered Pumps lor Low-L i f t Irrigation. M A F - I R R 1 Industrial Extension Program for Small - Farm Equipment, Paper No. 85 - 5054, American Society of Agricultural Engineers, LISA. Trasp, N.M. (1989). Treadle Pumps in Cameroon and Mali. Appropriate Technology International, Bulletin Number 18, May 1989. Watt, S.B. (1977). Chinese Chain and Washer Pumps., Intermediate Technology Publications, London, England.