in bearings, which are in turn supported by a suitable framework. The sprocket
is connected to the engine by a chain drive of No. 1030 or No. 1240 chain, the
same as is used in driving a rotary draw works. The engine sets on sills which
are in the same position as for use in drilling a well with rotary tools. The
throttle controlling the speed of the engine, the reversing lever and the clutch
lever are in the same relative position on the derrick floor as they are in rotary
drilling. Hence, anyone familiar with the operation of rotary drilling equip-
ment will easily adapt himself to the operating of this equipment in pulling
rods and tubing and in bailing. By means of wrist pins in the crank arms, a
reciprocating motion is given to the walking beam by means of the pitmans and
the cross yoke. The walking beam, Samson post, and saddle irons are identical
with those in use in the ordinary standard rig, except for the notches in the
lower side of the walking beam. These two notches are so cut as to make the
beam suitable on a derrick having either a 22-foot or a 24-foot base. On the
end of the walking beam which protrudes outside of the derrick an ordinary
counterweight is attached. This is not shown in the illustration.
The lower connection from the pitman to the wrist pin is adjustable. This
is the means of adjusting the length of pitman so as to make up for any irregu-
larities in the level of the derrick floor.
The crank arms having holes as shown in the accompanying illustrations will
allow for pumping strokes of 24, 32, 40, and 48 inches. In test runs at Sara-
toga, Tex., in a well 1,500 feet deep, it was possible to maintain a pumping
speed of 30 strokes per minute of a length of 40 inches without any trouble
A standard pumping rig having a 30-inch pulley on the steam engine and a
10-foot band wheel (4 to 1 ratio) will impart a pumping speed of 30 strokes per
minute when the engine is running at 120 revolutions per minute. The Suman
pumping jack using an 8-tooth sprocket on the engine and a 27-tooth sprocket
on the drive shaft (3.375 to 1 ratio) will impart a pumping speed of 30 strokes
per minute with the engine running at only 101.25 revolutions per minute.
If a 32-tooth sprocket is used on the drive shaft the power ratio becomes iden-
tical with that on the standard rig.
It is believed that the depreciation of this type of pumping jack is only about
one-fourth that of the ordinary standard rig. The cost of this outfit is only
about one-third the cost of the ordinary standard pumping rig using 5-inch
The power ratios being practically the same, it is quite evident that pulling
rods and tubing and bailing can be carried on with the Suman jack with the
same degree of speed and power as with the standard rig. When carrying on
these operations the pitmans are disconnected and the walking beam is pointed
up into the derrick in the same manner as when using the ordinary standard
rig. In the operation of bull wheels, however, one man is required at the brake
and another one at the throttle. In the operation of the Suman jack doing
identical work, one man handles both the brake and the throttle.
UNIT PUMPING POWER.
Some of the oil-well supply companies manufacture unit pumping
outfits for a single well, which by using a balanced load can often
be adapted for pumping a group of two or three wells. These unit
powers generally consist of a small wooden or steel counterbalance
beam, Samson post, and pitman mounted on a concrete, wooden, or
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 June 2, 2015.