MICROFICHE REFERENCE LIBFUUW - Cd3wd.com

70engine (2-3 hp) as the prime mover, performance testing was doneby SubinPinkayan at the SEATO Graduate School of Engineering(Bangkok) on a waterladder similar to those used throughout much of Asia. This pump, with a2-3 hp engine driver, delivered about 0.8 cfs at a 3 ft head. Molenaar(1956) reported that a water ladder powered by 4 men could lift 0.23 cfs3 ft. The water ladder, as tested by Pinkayan, is normally limited to 3ft lifts and for operation by two men (i.e., with foot treadle) would costabout $35-$40 (Molenaar, 1956).3.3.1.3 Chain PumpThe chain pump is very similar in design and operation to thewater ladder. In fact, the names are often used interchangeably. Additiona:names for this device include:chain-disc pump Liberation waterwheel (China)pater-noster pump chaplet pumpIn essence, the chain pump is a water ladder with an enclosed trough whichallows its use on steep inclines or vertically, as in Figure 3.19. Thisenclosed trough eliminates the spacing/depth ratio limit on the capacityof water ladder paddles, i.e., except for leakage losses, the entirespace between paddles or discs can be filled with water.A length of circular pipe commonly serves as the enclosed trough,while the circular discs pulled through it are often fitted with rubberor leather perimeter rings to reduce leakage between discs and the pipe.As in the water ladder, a driving sprocket or notched wheel engages the endlesschain at the upper level to pull it around. In vertical installationssuch as Figure 3.37, the chain is long enough to allow it to hang freebelow the pipe bottom. This lower pipe ,end is usually flared to facilitateentry of the discs into the pipe.