MICROFICHE REFERENCE LIBFUUW - Cd3wd.com

123an overall gear ratio of 1 to 120, increases the first driving gear’s lo-20rpm to a final 1200-2400 rpm which is usable for a centrifugal pump. Fora range of lifts from 3.3 ft to 7.5 ft, the small centrifugal used suppliedfrom 330 to 25 cfh, respectively. The use of worm gears and/or fewergears with higher ratios to reduce friction are among the recommendationsmade to increase efficiency. (A detailed description of this work isgiven in a 1967 thesisby Garg.)Table 5.1 outlines the basic motions which can be provided by manualpower and some of the typical water lifter/transmission combinationswith which they can be utilized.5.3 AnimalLike manual power, animals provide a relatively mobile source ofdriving energy which can be utilized for several duties, e.g., plowing,transportation, water lifting. Thus, if an animal can be used for tasksother than just water lifting, the price and maintenance costs of thatanimal can be tltime-shared’lby each task for economic purposes.Although draft animals constitute a common and vital source of powerin many developing countries, their upkeep can be particularly difficultin areas where water is scarce, rainfall is variable, or livestock diseaseis common (Merrill, 1976). If an operator does not want to, or cannot,provide for the care and feeding of an animal, or he only needs theanimal(s) for a short period of time, be can rent or lease the animals.In this case his prime movers cost for water lifting will be the rent(time-shared if used for other duties). However, when an operator awns hisown animal(s), he will have an initial purchase cost plus maintenance.Initial costs will vary greatly depending on the type, size, and conditionof the animal, and the geographic area.