Smith-Dunn process 17 in the shallow oil fields of Marietta, Ohio,
where the Watts and Dunn displacement pump is used to raise the
oil. This pump and its improvements are covered by United States
patents 1,187,579, 1,190,491, 1,198,881, 1,202,932, and 1,206,065.
Briefly, this pump consists of a casing, placed near the bottom
of the well. A valve at the bottom of the casilu chamber com-
municates with the fluid to be lifted. A screen below this valve
prevents the entrance of dirt into the chamber. A float within the
casing is attached to a steel rod that extends through a stuffing box
at the upper end of the casing and is connected, through a coil
spring and counterbalanced arm, to the valve at the casing head
controlling the supply of compressed air to the casing chamber.
The casing chamber also has an outlet pipe extending into the
chamber and along its side to a point below the check valve of the
As the chamber fills with oil the float rises until it reaches the top
of the chamber, where the air-valve connections open the valve. The
air admitted to the top of the casing chamber forces the contained
oil through the discharge pipe. When the air has forced all of the
oil from the casing chamber, the float has dropped to the bottom
of the chamber closing the air valve. This process is repeated as
often as the casing chamber fills with oil.
A synopsis of the general principles of the air-lift system Is taken
from Technical Paper 70, Bureau of Mines, is as follows:
The operation of the air lift depends on the buoyancy of aerated liquids.
To obtain the desired results, air is pumped into the well through a small
pipe to a convenient point below the surface of the liquid, where it is allowed
to discharge into a larger pipe through which the aerated fluid rises above
ground. It is important that air be admitted to the fluid in a finely divided
state and in such a manner as to realize the full cross-sectional area of the
discharge pipe for the passage of the liquid. The pumping of water by this
method' has been successfully accomplished for many years and most of the
experience gained with the air lift has been obtained in pumping water.
The successful operation of the air lift for pumping oil and water mixtures
depends upon a number of factors, most important of which are: (1) The
height of the column of fluid that the aerated mixture has to overcome or the
height from air inlet to the surface of liquid in the well. This is known as
17 Lewis, J. O., Methods for increasing the recovery from oil sands: Bull. 148, Bureau
of Mines, 1917, pp. 36-91.
1s Arnold, Ralph, and Garfias, V. R., Methods of oil recovery in California: Tech.
Paper 70, Bureau of Mines, 1914, pp. 44; Ambrose, A. W., Underground conditions in oil
fields: Bull. 195, Bureau of Mines, 1921, pp. 237 (containing on pages 75-77 an extract
from an unpublished manuscript of the Bureau of Mines, by Wagy, E. W., The use of
compressed air in California for producing mixtures of oil and water).
George, H. C. Surface Machinery and Methods for Oil-Well Pumping. Washington D.C.. UNT Digital Library. http://digital.library.unt.edu/ark:/67531/metadc12407/. Accessed May 5, 2015.