The Peasant's Hydraulic Ram Pump

This is a pump that uses the power of water flowing downhill to deliver a supply of water to a much higher level. Pumps like this are relatively easy to build at home, for very little cost.

How does it work?

Water is run into a feed pipe (with a screen to keep out debris) from a river or stream. As the water runs down the pipe it picks up speed and, therefore, momentum. As the flow builds up to a fast rate, it overcomes the mechanical spring pressure on the main valve, causing the valve to close. This stops the flow of water throught the feed pipe, but since it has built up momentum, the pressure inside the pump increases. This forces water through the check valve which then momentarily compresses the air in the air chamber. The air then decompresses, pushing the water through and out of the delivery pipe, while the check valve prevents water from moving backwards through the pump. As the water flows through the delivery pipe and out of the pump, the pressure inside the pump drops, allowing the main valve to open again. This allows the water in the feed pipe to begin flowing again, starting the cycle all over again.

All that is required to make a pump like this function is a minimum of about two feet of drop in the feed pipe, although more drop is desireable as it provides increased flow rates and greater maximum delivery heights.

Free water forever!

All the equipment needed:

Details of the main valve:

For an old Mother Earth News article about building your own ram pump, go here.