Best Explained Do-It-Yourself Step by Step Hydraulic Ram Pump

Categories: Hydro Power


A hydraulic ram (or water ram) pump is a simple, motorless device for pumping water at low flow rates. It uses the energy of flowing water to lift water from a stream, pond, or spring to an elevated storage tank or to a discharge point. It is suitable for use where small quantities of water are required and power supplies are limited, such as for household, garden, or livestock water supply. A hydraulic ram pump is useful where the water source flows constantly and the usable fall from the water source to the pump location is at least 3 feet

Principles of Operation

Components of a hydraulic ram pump are illustrated in Figure 1. Its operation is based on converting the velocity energy in flowing water into elevation lift. Water flows from the source through the drive pipe  and escapes through the waste valve  until it builds enough pressure to suddenly close the waste valve. Water then surges through the interior discharge valve  into the air chamber , compressing air trapped in the chamber.

When the pressurized water reaches equilibrium with the trapped air, it rebounds, causing the discharge valve  to close. Pressurized water then escapes from the air chamber through a check valve and up the delivery pipe  to its destination. The closing of the discharge valve causes a slight vacuum, allowing the waste valve  to open again, initiating a new cycle.

The cycle repeats between 20 and 100 times per minute, depending upon the flow rate. If properly installed, a hydraulic ram will operate continuously with a minimum of attention as long as the flowing water supply is continuous and excess water is drained away from the pump.


The location of the water source in relation to the desired point of water use determines how the hydraulic ram pump will be installed. The length of drive pipe should be at least 5 times the vertical fall to ensure proper operation. The length of delivery pipe is not usually considered important because friction losses in the delivery pipe are normally small due to low flow rates.

For very long delivery pipes or high flow rates, friction losses will have an impact on the performance of the hydraulic ram pump. The diameter of the delivery pipe should never be reduced below that recommended by the manufacturer. To measure the available source water flow rate from a spring or stream, build a small earthen dam with an outlet pipe for water to run through.

Place a large bucket or barrel of known volume below the outlet pipe, and measure the number of seconds it takes to fill the container. Then calculate the number of gallons per minute flowing through the outlet. For example, if it takes 30 seconds to fill a 5-gallon bucket, the available source water flow rate is 10 gpm. The lowest flow rates are typically in the summer months. Measure the flow rate during this period to ensure that the year-round capacity of the system is adequate.

This instructable shows how to build a fairly simple water pump that needs no energy input other than water flowing from a higher point to a lower point. Most of the pump is constructed from PVC, with a couple of bronze pieces thrown in for flavor. I was able to source all of the parts from a local hardware store (Lowes) for a bit under $100.

To function, the pump does require a reasonable amount of water that will drop at least 3'-5'. The level that the pump can raise water to depends on the water's head (total drop the water will make).

This design was worked out by Clemson University.

Download PDF Document with charts and recommendations depending on your needs, click here 

To read the document with step by step instructions on how to build it please follow this link.

via DIYOurself

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