Simple Gravity-Fed Piston Pump


Constant head pumps have a number of uses in the laboratory, and are often used to provide hydraulic heads for permeability measurements of lithologic materials. Since our lab suffers periodic power outages that interfere with long-term experiments, we designed and built a gravity-driven piston pump that requires no electricity. The pump is composed of a piston inserted into a vertical cylinder. The piston travels under the influence of iron weights added to the attached piston rod. Our pump used schedule 40 PVC pipe for the cylinder and acrylic for the piston. In eight months of constant use, there have been no pump failures. This pump operates over a pressure range of 20 kPa to 210 kPa. A small head loss occurs when using this pump due to falling water level in the cylinder. The calculated 5.97 kPa loss is not significant for our purposes and is less than the 13.8 kPa observed pressure variance due to asperities in the cylinder. Experiments in our machine shop indicate that honing the cylinder will significantly reduce the pressure variations. Design criteria and cost estimates for machining parts for this type of pump are included. This pump may be useful for long-term experiments at relatively low fluid pressures.


Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Gravity; Pressure; Pump

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Document Type

Article - Journal

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© 2003 Society of Sigma Gamma Epsilon, All rights reserved.

Publication Date

01 Mar 2003

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