MICROFICHE REFERENCE LIBFUUW - Cd3wd.com

51and steps off to allow buoyancy to lift it. Although no information isavailable, this device appears cheaper and easier to build and maintainthan the conventional doon.Through recent communication with W. D. Kemper in Pakistan, we havelearned of the development of a double-acting, foot-operated gutter. Asshown in Figure 3.10b, two pans are connected by a rope which passes overa pulley. The operator stands with one foot on each pan and alternatelyshifts his weight from one pan to the other. By means of a flapped openingin the outboard end of each pan, it fills and is then raised anddrained out the shore-hinged end. Kemper reports that a man in goodcondition can lift 800 cfh (100 gpm) one foot for several hours. Overshort periods, a rate of 130 gpm has been reached. It appears that thisdevice is limited to one or two foot lifts, but is quite efficient andeasy to operate. As this device is still under study, no data on costsor efficiencyis yet available.3.2.3 Piston-, Plunger-, and Bucket PumpsThis third subclass of reciprocating methods ranges from the simple,hand "lift pump" (Fig. 3.12 to the sophisticated, direct-acting "steampump" (Fig. 3.11. Unlike the reciprocating devices previously discussed,these pumps do not need to he submerged (have a static suction head) tolift water, but instead have the ability to "suck" water from a staticsuction lift (see Section 2.2). All pumps in this class utilize as theirprimary component one of three similar devices to lift the water;(a) The plunger-pump uses a soild or semi-solid cylinder (plunger)to displace the water in a surrounding hollow cylinder. Whenthe plunger withdraws (upward) from the cylinder it creates adrop in pressure within the cylinder and thus allows water to