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Rope pump construction manual

Introduction

The rope pump is a very cheap and easy to build pump which can be made of mostly waste materials. Because of its simplicity it can be built and maintained by people who aren't technically grounded. Some practical skills are required though.
The picture on the front shows a rope pump which has been made by course-members during the Technical-week 1997 of the WOT, under supervision of Henk Holtslag.

Figure 1 shows the fundamental construction of a rope pump. A rope pump is made of a rope with attached pistons which runs through a (raising) tube. The lower side of the tube reaches the ground water and the upper side reaches above the surface. The pistons, which are attached to the rope, fit in the tube with a small tolerance (0.2…0.5mm). By pulling the rope through the tube a vacuum is created by the pistons so that water is taken up. A thin waterfilm between the piston and the tube wall takes care of the greasing and also contributes to the closing between the piston and the tube. At the upper end the rope runs over a wheel which pulls the rope through the tube. The rope runs smoothly through the tube because of a construction at the lower end of the tube.

The rope pump (made of simple materials) can be used till a depth of 40 metres. The deeper the water, the smaller the diameter of the (raising) tube. Otherwise too much weigth of water would have to be lifted. Especially for small tubes belonging to big pumpdepths it's important that the pistons are made the right size accurately.

Table 1 and 2 show which tubediameter must be used with certain pumpheights for two most used wheeldiameters.

**Table1** Pumpheights in relation to the **inner** tubediameter with use of a **wheeldiameter of 0.36** metres.
Pumpheight(metres) Pumpheight(foot)	0...6 0...20	6...9 20...30	9...20 30...65	20...35 65...115	35...40 115...130
Raising tubediameter(") Raising tubediameter(mm)	1½ 44.5	1¼ 38.1	1 25.4	¾ 19.1	½ 12.7
Output (litres / turn)	1.4	1.0	0.5	0.3	0.1

**Table2** Pumpheights in relation to the **inner** tubediameter with use of a **wheeldiameter of 0.54** metres.
Pumpheight(metres) Pumpheight(foot)	0...4.5 0...15	4.5...6 15...20	6...13 20...43	13...25 43...82	25...40 82...130
Raising tubediameter(") Raising tubediameter(mm)	1½ 44.5	1¼ 38.1	1 25.4	¾ 19.1	½ 12.7
Output (litres / turn)	2.1	1.5	0.7	0.4	0.2

1 litre = 0.220 UK gallon = 0.264 US gallon.

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