Surface Machinery and Methods for Oil-Well Pumping

30 SURFACE MACHINERY AND METHODS FOR OIL-WELL PUMPING.
obstructed, the engine should be stopped and the scale removed from
the jacket.
The scale can be softened by draining about half the water out
of the jacket, and pouring in a gallon of kerosene oil. The inlet
and outlet pipes are then plugged and the engine is started and
run for 15 or 20 minutes with the mixture of oil and water in the
cylinder. The engine is then stopped and allowed to cool. The
scale becomes soft like mud and can readily be removed. A mix-
ture of 1 part of sulphuric acid and 10 parts of water allowed to
stand in the engine jacket for 10 or 12 hours will give the same
result.
Some oil-field operators have an ingenious system for stopping
the gas engine when water circulation is deficient, if the magneto
is used for ignition and a pump is used for water circulation. A
pail with a hole in the bottom is suspended under the end of the
water discharge pipe at the water tank. The rope supporting the
pail passes over a small pulley attached above the tank, into the
engine house, and over another pulley fastened directly above the
spark plug of the engine, terminating in a steel counterweight con-
nected by a wire to the engine piping. When enough water cir-
culates, the discharge water running into the suspended pail at the
circulating-water tank holds the counterweight away from the spark
plug. But when the circulation becomes deficient or ceases, the water
runs out of the pail and the counterweight drops on the spark plug,
shorts the ignition, and stops the engine. This arrangement is espe-
cially convenient when the man in charge must spend much of his
time at other wells.
Other troubles in the water-circulating system are caused by the
swelling of packing at unions in the water pipe, which obstructs the
flow of water; breaking of the belt driving the centrifugal pump;
stripping or wearing of the impeller blades in the pump; and crack-
ing of the water jacket in winter because of failure to drain the jacket
when the engine is shut down. All of these troubles can be elimi-
nated by proper care and attention.
ENGINE CLUTCH.
If the gas engine is used for pulling rods and tubing, a reversible
clutch is needed; otherwise an ordinary clutch suffices. The reversing
clutch enables the operator to reverse the motion of the belt without
stopping the engine. Plate VII, B, shows a common type of re-
versing gear.
The clutch is mounted on an extension of the engine shaft at b
by means of a flange coupling, the outer end being supported and

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 April 20, 2014.