MICROFICHE REFERENCE LIBFUUW - Cd3wd.com

Because the components are not yet commerciallyproduced as a unit,these pumps are still rather expensive for use in developing countries.The air-cooled system which produced the results in Table 3.9 cost about$1,420 for the tanks, plumbing, and insulation, and $4.50 per ft2 for thecollector. The water-cooled system cost about $2,100, plus the $4.50per ft2 of collector, i.e., about $6,400 total. Of course, the operatingcost is almost nil--only an occasional recharge of the working fluid.With further development to cut initial costs and improve efficiency, thelack of moving parts (except check valves) and ease of operation byunskilled labor, make this sys.tem a feasible solution to reducing pumpingcosts in a time of rising fuel costs.The second recent development of the displacement method is the footoperated device in Figure 3.32. It is being manufactured commerciallyby a French company for use primarily in developing countries. Asshown in the ,figure, a foot pedal reciprocates a small air-piston whichis connected to a displacement cylinder in the water supply via a flexiblehose. As in the other displacement methods, the change and exhaust of airby the piston causes discharge and filling of the cylinder, respectively.The discharge flow is through another flexible hose which is connected atthe surface to appropriate plumbing. In a design for 4 in. diameter wells,this device is reported to deliver 53 cfh at a 66 ft head, and 18 chf at200 ft (Mengin, 1976).3.4.3 PulsometerAlthough the pulsometer probably cannot be found in use anywhere today,as mentioned in Chapter 1, it was commonly used for drainage purposes aroundthe turn of this century. It utilizes the principles of both the steam and