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Christian Community Services, Kenya

Adventures with the ROPE and WASHER Pump

Stephen Burgess
ACK Eldoret Region, Christian Community Services

As part of the Water Supply and Sanitation project (WATSAN) rural communities are digging hand dug wells in their homesteads. The wells are then lined inside and covered with a concrete slab to prevent dirt entering the well. It is amazing to see what determination a community have to find clean water- imagine going 25 metres or more down below ground in an 80cm diameter hole, digging by hand! Challenging indeed, but the result is a clean source of water close to the home. In one community, at Matharu, south east of Eldoret, 60 wells have been dug and lined in this way.

The next concern was how to get the water out of the wells, which were between 15 to 25 metres deep. Most of the community members used a rope and plastic " bucket"; a few had installed manufactured Indian handpumps. Both methods served their purpose but the handpumps were expensive to buy and difficult to maintain.
A rope and bucket was cheap but it was hard work to lift the daily water needs of 200 litres per day; the ladies, in particular, complained of backache. Also, it was realised that the rope and bucket thrown into the well was a source of contamination, since more often than not it was left lying on the ground among the mud. One solution would be a simple, low cost and easily maintained pump. The Rope and Washer pump was looked at as one option.

The Rope and Washer Pump is an old technology, perhaps first invented by the Chinese thousands of years ago; it is documented as a chain and washer pump. In Kenya demonstrations of Rope and Washer pumps have been made and used for more than 25 years, quite successfully too. The technology was in the hands of a few water supply technicians, particularly in NGO projects, and local, inventive artisans who had seen demonstrations or saw plans in construction manuals. They made working good pumps.

However, it was difficult for someone to get hold of a ready-made pump and more difficult to get hold of a design which had been tested, used and proven.

The WATSAN project of ACK Eldoret Region, Christian Community Services set out to address this need and in doing so was able to find a suitable pump for the rural farmer. Using previous experiences plus ideas from various sources a rope and washer pump was made in 1998 and tested on the WATSAN project office well. With more information from the very successful ROPE PUMP project in Nicaragua further modifications were made.

The pump consists of 4 parts:
See Figures 1 and 2

- The main drive wheel, welded steel spokes with a tyre rim, a steel pipe axle mounted on two posts across the well.

- The guide pulley, fabricated from mild steel, set in concrete, at the bottom of the well.
- The nylon rope, with rubber washers spaced at intervals. The rope goes around the main wheel and the guide pulley and up through the riser pipe.
- The riser pipe, ž" PVC class C, and outlet TEE.

Turning the main wheel causes the rope and washers to move up through the riser pipe lifting the water.

The initial pump design worked well on the 6m deep office well and was then installed in a few rural community wells; with ideas from community users further modifications were made.

Now, in the WATSAN project more than 100 pumps have been installed and are being used in rural communities like Matharu. The wells are 15m to 25m deep. The pump has proved easy to install and use and can fill a 20litre bucket in one minute. The community users like the pump because it is easy to maintain and has proved quite durable. In one year of operation the only wear has been on the rubber washers and rope. In some cases this has been renewed after about 1 year (See table 1).

The modifications were based on the user comments and suggestions. In the development of any technology involving the users has proved crucial, as the pump has become appropriate to their need and socio- economic context. Two important points in the design are:

1. How to prevent the pump rotating backwards: A

freewheel from a bicycle was welded onto one end of the axle acting as a non- return mechanisms and a bearing.
2. The riser pipe must be class C or stronger and when joining free of any slight obstructions to the free movement of the washer. Currently washers punched from old car tyres are used. The diameter is critical, just slightly less than the riser pipe; too large and friction is high making the pump difficult to turn, too small and water leaks back past the washer so flow rate is reduced.

One strategy of the WATSAN project is to train others to become self-reliant and to promote sustainability of technology. This has been achieved in regard to the Rope and Washer pump in the following ways:

-A local artisan was trained in 1998 how to fabricate the pump, and how to install the pump. One could now say that the artisan, Simon, and his workers, are experts in Rope and Washer Pumps.
-Simon not only makes pumps for the WATSAN project but also for any other individual or organisation wanting a pump.
- Simon alone has made and sold over 100 pumps and installed many on site.
-In the last 3 years more than 30 artisans from other areas of Kenya and Tanzania have been trained by Simon.
The rope and washer pump workshop with Simon & Co

- Artisans in the ACK WATSAN project and other NGO in Kenya have been trained and are installing pumps all over Kenya.
- The pump is being promoted and advertised by a local Appropriate Technology company.
- Further ideas for development and improvement are continually being considered. For example a rope and washer pump was successfully fitted to a 40m deep well but using ˝" washers and riser pipe. New moulded washers are being manufactured.
- Being an appropriate design and using local skills, the cost has been kept low, Ksh 2500 to Ksh 4,000, depending on the depth of well. (Sterling Pounds 25 to 40).
- It is important that the Rope and Washer pump does not belong to the ACK WATSAN project, but to the users. Some of the organisations and artisans trained are now developing the pump further according to their local needs and context.

TABLE 1: Rope and Washer Pumping tests from Matharu . The tests were done 6 months to 1 year after installation. The pumps are in constant use, pumping about 600 litres of water per day.

NAME/PLACE

DATE

WELL

WASHER

WHEEL

FLOW RATE

Litres / s

Hydraulic efficiency %

COMMENT

MATHARU

INSTALLED

DEPTH(M)

SPACING

(CM)

DIA (CM)

6.11.01