28 SURFACE MACHINERY AND METHODS FOR OIL-WELL PUMPING.
engine should not be run for any length of time with a hot bearing
as the bearing may seize tight on the shaft and wreck the engine.
The object of a cooling system on internal-combustion engines is
to keep the cylinder walls cool enough to prevent vaporization of
the lubricating oil and thus insure good lubrication of the cylinder
and piston. Vaporization of the oil through overheating of the
cylinder will cause rapid wear of the piston rings and cylinder.
Gas engine cylinders are either air cooled or water cooled. The
common type of small gas engine, which is air cooled, has a small
fan mounted on one side of the cylinder and driven by a belt from
the flywheel. The fan keeps the engine cool, provided that the belt
used for driving the fan is kept tight and in good repair. By this
system there is little danger of decreasing the efficiency of the engine
by keeping the cylinder too cool, as sometimes happens when the
cylinder is cooled with cold water.
Some small gas engines are water cooled, without the use of water-
circulating tanks, by means of a hopper extension of the water jacket
which is open to the air. The evaporation of the circulating water
keeps the engine cool. As the hopper is open to the air, the tem-
perature of the cylinder can not exceed 212 F., the boiling point of
water, provided the hopper is kept filled with water.
The standard practice with most types of gas engines is to inclose
the cylinder within a covered water jacket through which water is
kept circulating. Rapid circulation of cold water greatly reduces
efficiency of the gas engine by the chilling of the expanding gases in
the cylinder. To insure the best results, from 4 to 6 gallons per
horsepower should pass through the jacket each hour. The water
leaving the jacket should not have a temperature in excess of 1600 F.,
for if it contains an appreciable amount of mineral matter, which
frequently happens, higher temperatures cause rapid deposition of
mineral within the water jacket.
In oil fields with ample water supply and suitable topography,
the water is frequently piped by gravity from reservoirs or springs to
the water jacket, without any provision made for return. The objec-
tion to this system is chilling of the cylinder, due to the too rapid
circulation of the water, if the water is cold. To flow water from a
tank through the water jacket by means of connecting pipes is stand-
ard practice. The water enters the water jacket by means of a pipe
connecting the bottom of the tank with the bottom of the water
jacket.- The water is returned to the tank by means of a pipe con-
necting the top of the water jacket with the surface of the water
in the tank. The water-circulating pipes should be as free from
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 December 5, 2013.