74 SURFACE MACHINERY AND METHODS FOR OIL-WELL PUMPING.
driving the power, B. is the idler or belt tightener, and C is the
band wheel with eccentrics.
Most operators who have used both steel and wooden band wheels
prefer the former because they are lighter, smoother, give less wear
on the belt, and are more rigid. A wooden wheel must be made of
seasoned lumber, or it may become rim bound and warp, which will
necessitate removing a section between two of the spokes, drawing
up the wheel, and rebuilding the removed section. If a wooden
wheel is dished 2 inches toward the center, any tendency to sag will
tighten the wheel, and the oil used for lubricating the shaft will not
tend to run toward the rim and get on the belt.
Plate XVII, shows a new band-wheel power before being housed,
with the engine a, the idler b, the steel-rod-braced wooden band-
wheel with eccentrics for shackle-line attachment c, take-off rail for
shackle lines d, water-circulating tank for engine e, and concrete
floor. Plate XVIII, A, shows a steel band-wheel, with eccentrics
in place, ready for the belt.
DIRECT-CONNECTED ELECTRIC MOTOR-DRIVEN AND GEARED PUMPING
With the development of electric power for pumping oil wells,
the type of equipment has been improved. Recently attention has
been directed to the possible use of a direct-connected motor-driven
and geared pumping power. One of the larger oil companies is
developing a power of this type. Briefly, it consists of gears and
eccentrics driven by an electric motor bolted to the top of the power
frame. Although the merits of this type of power have not yet been
proved by service, its use will doubtless be general in a few years.
IDLERS FOR BAND-WHEEL POWERS.
The idler should be so placed that the upper length of belt, as it
leaves the engine, travels as nearly as possible directly above the
lower length. The idler frame should be parallel to the lower belt
length so that as the belt stretches and the idler is tightened, a side
pull tending to strain the fiber will not be developed in the belt as
it leaves the engine pulley. The idler should not be too near the
engine pulley, for then the friction surface of the belt on the band
wheel will be decreased, requiring a tighter belt, and the belt will be
twisted in too short a distance to meet the face of the idler, which
also will tend to strain the fiber of the belt. The idler should not
be placed too near the band wheel, because then the belt is twisted
in too short a space as it leaves the face of the idler to meet the face
of the band wheel, which likewise tends to strain the belt fiber. The
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 17, 2014.