46 SURFACE MACHINERY AND METHODS FOR OIL-WELL PUMPING.
with a shackle-line attachment at e, leading to a counterweight like
that sometimes used at a well pumping " on the beam," as shown in
Plate XI, B, at a (p. 60), which provides for the return stroke of
Plate IX, B, at a shows a tail pump worked by a pumping jack
driven from a central power. The work arm of the jack has a scrap-
iron weight to provide for the return or down stroke of the pump.
Much heavier installations of this type are used in the Kern River
oil fields, California, to pump oil from sumps to flumes or to produc-
GAS OR VACUUM PUMPS.
At many pumping wells on which vacuum is maintained the
vacuum pumps are often run by the equipment used to pump oil. At
wells pumping on the beam, the gas pump is often placed and
worked like the tail pump shown in Plate VIII, A. The pump
consists of a gas cylinder and piston with rod connection to the
walking beam. Most types are double acting, and are provided with
intake and discharge gas ports and valves at each end of the cylinder.
Where a central power is used, a gas cylinder is generally direct
connected to the steam or gas engine used for the power. When
electric power is used, a gas pump of suitable size is generally belt-
driven from a motor; however, some types are gear-driven from the
In some oil fields a large central gas compression and pumping
plant is built which controls the vacuum on all the wells of a
number of properties, maintaining practically the same vacuum on
all wells, and extracting the gasoline from the gas before returning
it for field use.
For use at these gasoline extraction plants, some manufacturers
recommend their compressors as vacuum pumps, while other manu-
facturers, rather than design the low-pressure cylinder of the com-
pressor for this work, make a gas or vacuum pump for bringing the
gas from the wells to the compressors. If a vacuum is not desired
at the wells supplying gas to the gasoline plant, a back-pressure
regulator, set to work at any desired pressure, is installed and is
generally found satisfactory.
ELECTRIC GENERATING EQUIPMENT.
Up to the present time the extensive use of electric power for
pumping oil wells has been chiefly at fields so located that the power
can be purchased from the public service corporations. In Cali-
fornia, of the 10,000 producing oil wells, about one-third are pumped
with electric power usually obtained from the large power" companies
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 August 29, 2015.