Water Pumping System for Nkuv, Cameroon

Becky Lathrop

Summary:

The water pumping system, consisting of a water entry device and a hydraulic ram pump, were designed specifically to fit the needs of the village of Nkuv, Cameroon. Though there is an adequate water supply available to the villagers in Nkuv this water is not conveniently located nor is it sufficiently clean. Currently, villagers must travel to the stream to retrieve their water which contains many contaminants from bathing and farm runoff. This water pumping system is designed to draw water from the stream at a less contaminated point in the river and to deliver it to a storage tank so that it can then be directed toward the village using a piping system which will be developed at a later date.
There were a number of different designs that were considered for this project. It was discovered that prefabricated hydraulic ram pumps can be purchased, however, they are very expensive and may not be easily repairable with the tools and resources available in Cameroon. Other options for the pump itself included using a large siphon, a wind-powered water pump, or a prefabricated sling pump. Once it was decided that a self-constructed hydraulic ram pump would be optimal for the pump three different plans were looked at for the construction directions. The final design final design is adapted from a set of instructions generated at Clemson University. Different designs were also considered for the inlet to the pipe, some of which included a funnel design and pre-constructed strainer which is designed to fit onto PVC piping. The final inlet design was hand crafted to increase the ease of repair or re-construction in Cameroon; it consists of a wire cage surrounding a punctured PVC pipe to allow for maximum water flow into the pipe.
It was decided that the pump and inlet pipe should be made almost entirely out of PVC piping due to the availability of materials in Cameroon, as well as the ease of transportation and construction. All PVC parts are connected together using glue, and the metal connections are sealed with Teflon tape.
This pump functions by the opening and closing of a swing-check and spring-check valve system which pushes the water out of the pump with a higher velocity than that with which it enters the pump. Valves on both ends of the pump allow the water flow to be controlled easily, and unions allow for the easy disconnection of the pump from the piping in the event that repairs become necessary.
The design has proven to work successfully; a small modification was made to the original design. The modification keeps the swing-check valve from sealing shut by using a spring and rod attachment which protrudes into the valve thus allowing the valve to open and close more efficiently. Currently water can be pumped more than six feet above the water source at a rate of 0.5 gallons per minute. This rate is sufficient to fill a tank overnight which will supply at least 100 people.