India mk ii pumps are the most widely used hand pumps in the world. The design is simple, cost-effective and reliable and the fact that the design is open source means that anyone can fabricate and sell these pumps. These factors make them the idea pump for use in rural schools and villages in sub-Saharan Africa. In Uganda, the India mk ii hand pumps are considered the standard pump for Uganda and are the only pumps recommended by the Ministry of Water.
The India mk ii pumps were originally designed in the 1970s after a collaboration between UNICEF, the WHO, the Indian government and an Indian manufacturer. The design was based on an earlier pump created by a Swedish engineer and inventor named Oscar Carlsson with some minor changes. The changes included a longer pump handle to enabled the pump to be used without applying as much force.
The India Mark II hand pump has a PVC casing that is put in place during the drilling process. This is to keep the sides of the hole from collapsing. It also has a screen that lets water in while keeping sand and grit out. The pump cylinder is attached to a series of riser pipes and lowered below the water level. Inside those pipes runs a connecting rod that links the handle at the top to a plunger inside the cylinder. The riser pipes carry the water up to the spout.
Working the handle moves the plunger up and down. Inside the cylinder are two small one-way valves. On one stroke, a valve opens and water is drawn from the aquifer into the cylinder; on the return stroke, that valve closes and the other opens, pushing the captured water up into the riser pipe. With each pump, more water joins the column in the riser until it reaches the surface and flows from the spout. After a few strokes you get a steady stream of water.
For many years, the riser pipes were made from galvanized iron, however over time these have been known to rust, so now Drop in the Bucket only uses stainless steel riser pipes which never rust and have fewer issues.
