Surface Machinery and Methods for Oil-Well Pumping

PRIME MOVERS AND POWER PLANT MACHINERY.

gum or lint which might interfere with proper lubrication. Winter
temperatures affect the feed of oil cups. If the engine room is not
warmed in cold weather, lighter lubricating oils should be used, or
about 10 per cent of kerosene added to the heavier oil used for lubri-
cation.
The splash-feed system lubricates the bearings, piston, and cylin-
der by means of the oil spray caused by the end of the connecting
rod splashing through an oil puddle in the bottom of the closed
crank case. By this system constant and uniform lubrication is
maintained as the oil in the crank case is kept up to the overflow
point. A low-pressure circulating pump forces the oil into the bot-
tom of the closed crank case. By means of the overflow opening
the oil returns to the pump. Usually a wire-gauze strainer in the
suction pipe of the circulating pump keeps out dirt and carbon which
would otherwise interfere. This gauze should be removed fre-
quently and cleaned. Dirt, chips, and grit accumulating in the crank
case increase the wear on the bearings. All of the oil should be
removed from time to time and clean oil substituted.
One objection to the splash-feed system is the leakage of oil
through the crank case. Clogging of the overflow pipe will cause
an excess of oil in the crank case and light colored smoke at the
exhaust.
The force-feed system is the most reliable. A small pump driven
from the engine by a belt draws oil from a reservoir and forces it
through copper tubes or leads to the various bearings. In many
types of this system, each of the leads is provided with a regulating
valve and sight feed, by which the amount of oil delivered by each
is known and regulated. With this system the gauze oil-strainer
must be kept clean, so that the pump can always supply the neces-
sary oil. The oil piping should be cleaned at least once a year with
gasoline and a piece of wire to remove sediment which may have
accumulated. The driving belt for the oil pump should be kept
tight and in good repair so that oil circulation is always assured.
In oil-field practice the greatest need for proper lubrication is
found in the inner clutch bearing and the three crank-shaft bearings.
The inner bearing of the clutch should first be filled with hard oil
when the engine is first set up and should thereafter be filled from
time to time. Bearings equipped with soft oil cups show a greater
waste of oil than with hard oil cups, as with the former the thin oil
runs out between the shaft and the bearings.
Hot bearings often indicate lack of lubricating oil. This trouble
should be located and remedied at once.
Oil leaks, stoppage of oil pump, obstructions or holes in oil leads,
or too high viscosity of oil are common causes of hot bearings. An

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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 July 30, 2014.