MICROFICHE REFERENCE LIBFUUW - Cd3wd.com

46water. The capacity of this device could be significantly increased byextending and/or widening the outboard end as in Figure 3.7~.By using the same circular sweep as in the circular mot, two singlegutters can be operated by animal power, as indicated in Figure 3.8. Thisdevice, called the baldeo balti in the Punjab (Roberts and Singh, 1951))is primarily for lifts up to five feet, as are most gutter devices. Despitethe current use and wide variety of these gutter devices, no data on costsor performance is available for comparisons.Another modification of the simple gutter is the doon or jantu. Asseen in Figure 3.9a, it utilizes the counterweight principle of the shadouf.However, as it is used for small lifts, the counterweight is made sufficientto lift the water and gutter. By stepping up on the end of the gutter, theoperator can lower and submerge it. As can be seen, the lever and counter-_, weight must be designed to provide a greater moment (i.e., weight timeslever arm) than the full gutter, but less than the empty gutter plusoperator.Schioler (1975) has described what he believes to be a rather newmodification of the doon (Figure 3.9b) which again copies the picottahprinciple, i.e., the operator walks back and forth on the lever to providea movable counterweight. Because the gutter is attached at both ends tothe lever and rises with it, this picottah-style-doon (no specific namehas been reported) is capable of lifts greater than the conventional doon.Two more versions of the gutter have been recently introduced. Thefirst, shown in Figure 3.10a, utilizes a sealed air container, e.g., apetrol can, to lift the gutter by buoyancy instead of by counterweight.The operator merely steps on the outboard end of the gutter to fill it