Design of Hydraulic Ram Pump Systems

Abstract

Automatic hydraulic ram pumps are environmentally friendly devices using a renewable energy resource to pump water for domestic or agricultural use. Since being superseded by pumps using electrical or fossil fuel energy nearly a century ago, they are now coming back into favour in many parts of the developing world. I n the past, hydraulic ram pumps have been designed by rules-of-thumb having limited scientific basis. On-site adjustment has been used in the hope of rectifying the inevitable shortcomings of this process and ideal performance is rarely achieved. The present proposal for optimum design allows relevant system parameters (including the beat frequency) to be selected prior to installation. The paper shows how a ram pump system may be designed using two simple equations containing empirical factors dependent upon ram size, delivery head, material and wall thickness of the drive pipe and the configuration of the impulse valve. The design method is illustrated with reference to a number of existing tests. New experimental results for a 53 mm ram with Jive different impulse vdve strokes are also presented.Key words: automatic hydraulic ram pump design, empirical factors, effect of valve stroke, renewable energy NOTATION velocity ratio = uc/uo empirical factor in equation (5) (m-3) cross-sectional area of the drive pipe (m') valve flow area (m') empirical factor in equation (6) (s/m3) velocity of sound (m/s) discharge coefficient drive pipe diameter (m) friction factor acceleration due to gravity (9.8 m/s') delivery head (m) impulse valve head loss at closure (m) maximum delivery head (m) steady state head loss across impulse valve (m) supply head (m) total head prior to impulse valve closure (m) static head to close impulse valve (m) system loss coefficient constant (m/s) constant (s) length of drive pipe (m) impulse valve loss coefficient beat frequency (Hz) quantity delivered (m3/s) capacity of source (m3/s) steady state flow through impulse valve (m3/s) quantity wasted (m3/s) valve stroke (m, mm) wall thickness of drive pipe (m) cycle time (s) velocity to close impulse valve (m/s) steady state velocity (m/s) volume fraction of air trapped in drive pipe Rankine efficiency

Electricity Generation Using Water Lifting Force

“…Ram pumps are particularly appropriate for use in the developing world as their construction is basic and robust (Young, 1996). Since being superseded by pumps using fossil fuel energy nearly a century ago, they are now coming back into favor in many parts of the developing world (Young, 1995). Wherever a fall of water can be obtained, the hydram pump can be used as a comparatively cheap, simple and reliable means of raising water to considerable heights.…”

Determination of Hydraulic Ram Pump Performance: Experimental Results

“…e system consists of a drive pipe, waste valve, discharge valve, air (pressure) chamber, and delivery pipe ( Figure 1). e only moving parts of the system are the waste valve and the discharge valve which operate from the fluid dynamic actions of the pumping cycle [1].HRP is one of the simplest and the most environmentally friendly devices for domestic or agricultural use [2,3]. ere are a lot of people in a lot of countries that build and use this kind of pump.…”

Generating renewable power from water hammer pressure surges

“…Despite its potentially damaging effects, it is possible to harness the excess pressure of the water hammer for useful work. This is demonstrated by hydraulic ram pumps, which use the pressure generated by a periodically closing valve to pump water without an external fuel supply [15]. Hydraulic rams produce no greenhouse gas emissions during operation, are cheap to run, and are capable of operating passively for prolonged periods of time.…”