Campus Pump

The rope pump in the Pinetum of the UT

This rope pump, designed by the WOT, is a good example of technology made suitable for use in developing countries. The rope pump is used in 30 countries by 3 million people.

Operation

By turning the wheel an endless rope moves into the well and returns upwards through a rising tube. Rubber discs are mounted on the rope who have a certain clearance in the rising tube, the water will be lifted up with the rope. The rope pump can be used to water depths of 35 meters, and with a double service to 70 meters.

History

Principle working of the rope pump

The chain pump, from where the rope pump is derived, was used about 1000 years ago in ancient China. This pump consisted of disks attached to a chain fitted in a wooden or bamboo tube.

Since the availability of modern materials like PVC, the development of this type of pump has accelerated. By this a much lighter construction could be achieved and a larger lifting heights could be reached.

The target group

If a water pump will succeed in developing countries they must also be affordable. With a price of about $60, the rope pump is about 5-10 times cheaper than traditional piston pumps and is therefore ideal for family use. Women and children are traditionally those who care for the water. The operation may therefore not too heavy and the height should be adjusted accordingly. And not least in the West is just as good looks of great value.

Technology

The used technology should fit to the knowledge and fabrication possibilities present in small simply equipped workshops. The material choice is often limited. To make a design reproducible on location, only readily available pipe and sheet materials are used. To guarantee a long life span it is very important that the pump is easy to repair, utilities simply have the property that parts wear out or fail. All repairs must be performed with locally available resources and minor repairs must be carried out by the user.

The WOT 2011 model

Maintenance of a rope pump in Ghana

The WOT has build up extensive experience in recent years with rope pumps and used this knowledge to develop a new model. The most striking is that the frame is reduced to pole frame. This frame is not only easier to produce but also another 20% cheaper than the old frame. There is a single long tubular bearing applied instead of making two smaller bearings to prevent misalignment. In rope pumps simple bearings of steel pipe are used which are much cheaper than roller bearings. As long as there oiled regular, the life span is many years even if the pump is heavy used. When stopped pumping, the water column in the rise tube will rotate the wheel in the opposite direction that can cause dangerous situations. This has so far prevented with a locking hook. The WOT has developed a simple automatic one way break that is integrated in the bearing bushing.

As with previous rope pump designs a minimal number of different materials are used. Because paint is expensive in developing countries, only the places where the tubes are welded are painted. All the material used is galvanized and therefore already protected.