The Rope and Washer Pump

by Steve Herbert

The Water for Humanity Fund focuses on projects which mainly use manual pumping technologies. There are three main reasons for this. One is that in keeping with our emphasis on appropriate technologies, we feel these are devices which can be repaired by local know-how and with readily available parts, assuring the long-term sustainability of the project. The second reason is that we consider the manual pump to be more environmentally sustainable. There is much less waste of the resource, and it is unlikely that the water table can be over-pumped by a hand-operated device. Thirdly, it is less expensive technology and funds for this kind of water resources project maximizes the number of people helped per donation dollar.

Perhaps the best known manual pump and that most commonly installed in WFH projects is the India Mark II pump. This is basically a lever-action device which operates a pump in the bottom of the well that pushes the water up. However, there is another variety of manual pump which is cheaper to manufacture and actually has a greater depth capability than those like the India Mark II. It is called a “rope and washer” pump, or as it is commonly known in Latin America, the “bomba de mecate”. This type of pump operates by a hand crank which turns a bicycle-like wheel, minus the tire. Around the rim runs a rope and on the rope about every three feet is a stiff but flexible washer. The rope with washers descends into the well and around a pulley at the bottom, then ascends up through a PVC pipe with an inside diameter which matches the diameter of the washer. Water which becomes trapped between two washers is lifted up to the top of the well and out a discharge pipe.

There are various opinions about where the rope and washer pump originated, but most agree it was in Nicaragua. The first time I saw the bomba de macate, was in El Salvador in the year 2000. Later, in 2002, I had the chance to visit a facility manufacturing them in Nacaome, Honduras, and the owner of that manufacturing plant said he learned about the technology in Nicaragua. Five years later, I had the opportunity to visit a facility manufacturing the bomba de macate in Managua. There, the owner, Luis Rivera, introduced me to several different variations of this pump. These included a bicycle powered rope and washer pump, a pump run by animal traction, an elevated pump used to fill overhead tanks, a windmill-powered variety, and a motor-assisted version. Luis said he had been in business doing this for 17 years at that point. He explained that these pumps can be put into any type of well, dug or drilled, and to demonstrate he showed us the works which go in the bottom of PVC casing as small as 2" diameter. The diameter of the return tube is dependent upon the depth, though, he said, especially for manual pumping (1" up to 12m, 3/4" up to 21m, and 1/2" up to 50m).

This technology has been further refined since it was first introduced, and is still reaching for perfection. However, it has given rural peoples in the developing world a technology they can construct themselves and one which is more in reach for them economically.