RP-01638

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consists of a spring-activated poppet and the pump has a 3-inch (7.5-cm) cylinder, 7/16-inch (11-mm) pumping rod, and 1.25-inch (3-cm) drop pipe (riser pipe). The inlet-valve lining, piston cup, top gasket, and cylinder gasket of these pumps are made of leather, whereas the spout gasket is made of rubber. There are 42 different components and most of them are made of brass. Cold-drawn steel is used for the cylinder reducing coupling, bottom fulcrum pin, and piston rod. The handpumps provided by the Public Work Department are also included in this group because they are similar to DMR handpumps except that the drop pipe is slightly larger (1.5-inch, 3.8-cm diameter). The ARD handpump, which is usually called the Korat handpump, has been adopted by the Department of Health, the ARD Office, and the Local Administration Department. The pump mechanism consists of a rack and pinion (gear type). Leather is used for the piston seal, gasket, and bushing seal. All of the packing nut caps, valves, locks, and handle gear bushing are made of brass. The pump has a 3-inch (7.5-cm) cylinder and 1.25-inch (3-cm) drop pipe and is composed of 32 components. There is a slight difference in the handpump supplied by ARD. It is essentially the same as the Korat handpump except that it has a 3-inch (7.5-cm) cylinder made of polyvinyl chloride (PVC) and 1.25-inch (3-cm) drop pipe. The pumps supplied by the Local Administration Department are normally used for shallow wells. The advantages and disadvantages of the DMR and ARD handpumps are summarized in Table 1. In the Waterloo handpump, basically, all the components are made of rigid PVC and polyethylene, which are low cost commodity polymers. These plastics have been selected for ease of manufacture and low cost as well as for their efficiency. The below-ground components consist of a PVC well casing that also functions as the pump cylinder for the plastic piston. The plastic foot valve is constructed of components that are common to the piston (Fig. 1). The flow of water in the piston and foot valve is regulated by simple rubber plate valves. Polyethylene piston rings provide adequate hydraulic seals on the piston with much less frictional resistance than leather cups or rings. It has been found that wear is concentrated on the rings, which can be replaced easily, rather than on the well casing. The foot valve can be removed easily for inspection or repair and serves as a reserve piston whenever necessary. Both 2-inch (5-cm) and 3-inch (7.5-cm) diameter pistons were used in this study. The pistons and foot valves for the Waterloo pumps were made at the Asian Institute of Technology (AIT) using locally available PVC rods. The piston rings and foot-valve adapters were made from polyethylene supplied by IDRC. Based on the results of the laboratory and field tests, the piston and foot valve were later modified. Table 1. Advantages and disadvantages of existing handpumps in Thailand. DMR Advantages The air chamber of the above-ground component helps maintain a continuous flow of water The handle is made of a single piece of cast iron having appropriate shape and size, hence it is easy to operate and is durable Disadvantages Direct contact between the axle and the bushing causes rapid wear If the axle breaks, the handle can moue horizontally and may damage other parts The contact area between the axle and stuffing box is relatively loose. This can result in eccentric movement of the pumping rod and reduced pump efficiency The plunger could slam against the upper and lower parts of the cylinder if not properly installed The cast-iron fulcrum link is not strong enough and, under repeated use, tends to break ARD Advantages Vertical movement of the pumping rod is by using a rack and pinion There are fewer moving parts subject to wear and tear The shock-absorbing spring prevents the plunger from slamming against the upper and lower parts of the cylinder Disadvantages The flow of water is not continuous due to the absence of an air chamber The handle and pinion are separate parts and failure often occurs at this joint 22
L -' 0 inch 3 cm 8 A B Fig. 1. (A) Piston and (B) foot-valve assembly of Waterloo handpump: (1) polyethylene ring; (2) piston; (3) PVC plate valve; (4) brass valve guide; (5) flat washer; (6) nui; (7) boit; (8) boit with eye; and (9) polyethylene foot-valve adapter. Laboratory Testing Laboratory tests were carried out in the Structural Engineering Laboratory, AIT, for all three handpumps. The DMR and ARD handpumps were supplied by various government agencies and the Waterloo handpumps were made at AIT. The parameters that were varied were: stroke length of the piston, orifice/piston area ratio, and rate of pumping. A steel platform, 4 m high, was erected and a mechanized rocker arm was installed on this platform to drive 12 sets of handpumps Table 2. Testing prograrn for Waterloo handpump. Piston stroke length (inch)' Orifice/piston Speed of piston area ratio (%) (strokeslmin) 3 4 5 6 8 10 12.5 20 XXXXX X 17.0 30 XXXXX X 22.2 40 XXXXX X 50 XXXXX X 60 XXXXX X Note: For all three orifice/piston area ratios, tests were made for each piston speed and stroke combination. Each X represents a single test that was carried out twice. 'l inch = 2.54 cm. 23
Page 1 and 2: ARCHIV SHARP no. 1
Page 3 and 4: IDRC-204e Village Handpump Technolo
Page 5 and 6: Contents Preface ..................
Page 7 and 8: Preface Many factors are involved i
Page 9 and 10: Introduction The precise links betw
Page 11 and 12: The primary objectives of these stu
Page 13 and 14: Sri Lanka Pathirana Dharmadasa, lJp
Page 15 and 16: m O C O x 00 N .,y D+ O G+ CL C n Q
Page 17 and 18: 13 8 -6 7 9 10 A B C Fig. 4. (A) LI
Page 19 and 20: in the village can easily make a ne
Page 21 and 22: Table 2. Overview of performance da
Page 23: Thailand Pichai Nimityongskul and P
Page 27 and 28: The tensile strength of the PVC pip
Page 29 and 30: 0 4 A B OF inch 1 cm 4 10 01 1 inch
Page 31 and 32: water per 10-cm stroke, changes in
Page 33 and 34: Fig. 11. Below-ground components of
Page 35 and 36: Philippines Antonio Bravo This repo
Page 37 and 38: 2 Fig. 3. Modified version of above
Page 39 and 40: At a standard frequency of about 40
Page 41 and 42: Malaysia Goh Sing Yau The populatio
Page 43 and 44: AP. AP (FU + FD) (WW1 + WW2 + BP +
Page 45 and 46: Optimum Design It is difficult to s
Page 47 and 48: 10 4 1 A B Fig. 6. (A) Piston assem
Page 49 and 50: made from a 0.5-inch (1.27-cm) thic
Page 51 and 52: PK 006S2 312181 717181 60 1019181 0
Page 53 and 54: was found only in: (1) the top wood
Page 55 and 56: Overview of Technical Performance G
Page 57 and 58: Ln Country and model Pedestal Table
Page 59 and 60: Economic Analysis and Potential Mar
Page 61 and 62: program is being curtailed by the l
Page 63 and 64: cylinder: PVC is one-third the cost
Page 65 and 66: about 50% of the cost of the existi
Page 67 and 68: Table 7. Summary of important handp
Page 69 and 70: Conclusions In an era of rapid deve
Page 71 and 72: Malaya proposes to address this que
Page 73 and 74: Participants ZAINUDDIN ARSHAD, Mini

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