September 1942 ET-199
United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine
A POWER-DRIVEN MIXER FOR MAKING OIL EMULSIONS
By Minter DuPree and Willis Mathis,
Division of Fruit Insect Investigations
Although power-driven rixers suitable for making very small
amounts of oil emulsions are on the market, it was found desirable,
in making emulsion stock for experimental spraying, to have a mixer
with which 2 or 3 gallons could be prepared at one time. The
equipment developed for this purpose consists of an electric motor
and a mixer head mounted on a 2- by 10-inch dressed pine board
32 inches long, swung in a supporting frame by means of two iron
pins so placed that the weight is equal on either side of the pins.
The pins act as a pivot, allowing the end of the board on which the
agitator and shaft are mounted to be tilted up, as shown in figure
1, and to come to rest against the end-piece when lowered, as shown
in figures 2 and 4. By slipping the mixing vessel toward the
mixer with the board tilted up, and lowering the agitator and shaft
into it at the same time, the equipment is made ready for use
(fig. 3). This feature, besides making it possible to place the
vessel in position without lifting the entire apparatus, also
allows the agitator to be raised and lowered at an angle in the
material, providing more efficient mixing. The i-hp. motor has a
speed of 1,750 r.p.m. It is mounted by means of four 5/16- by
2j-inch bolts in slots so that the belt can be tightened when
desired. A 21-inch pulley is mounted on the shaft of the motor.
The mixer head consists of a !-inch pipe 10 inches long,
reamed to allow the free passage of a 1-inch steel shaft 30 inches
long, mounted with a 21-inch pulley and agitator, as shown in
figure 4. Brass bushings 3/4 inch long are fitted in each end of
the pipe to serve as bearings for the --inch shaft. (Ball or
roller bearings may be substituted for these, but are more expen-
sive.) The pipe is welded to a piece of 2-inch angle iron 4 inches
long containing two drilled holes for mounting on the board. This
is mounted so that the pulley on the motor is centered with the
pulley on the shaft. The shaft is held in place with i-inch-wide
brass collars and set screws, the collars being placed on the
shaft at each end of the pipe. A small grease cup is fitted onto
the pipe just under the top bearing and furnishes sufficient
lubrication for both bearings, as the pipe can be kept packed with
The agitator is a 4-inch steel disk, 3/16 inch thick, with
hub and set screw for fitting on the shaft. In order to increase
the agitation, the disk contains six -inch holes reamed at an
angle and three crimps equal distances apart (fig. 5). A paddle
type of agitator may also be used, and the length and pitch of the
blade can be made suitable for the type of agitation desired. The
power is transmitted by means of a j-inch V belt.
The frame is constructed of 2- by 2-inch dressed cypress,
cut as follows:
Front legs .............................. 2 pieces, 28 inches long.
Back legs ................................ 2 pieces, 291 inches long.
Side pieces, top .................. 2 pieces, 14 inches long.
Side pieces, bottom ........... 2 pieces, 22 inches long.
Ends, back and front .......... 4 pieces, 10- inches long.
The side and end braces are 5/16-inch iron rods, cut as follows:
Side braces ............................ 2 pieces, 17- inches long.
End braces .............................. 3 pieces, 13J inches long.
The joints formed by the legs and side pieces are fastened by
means of light I- by 2--inch stove bolts. Other joints are fastened
with wood screws. One pair of legs is sloped as shown in figure 4
to make the machine stable.
The total cost of the materials, exclusive of labor in
assembling the parts, amounted to about $20.
Explanation of Illustrations
Figure 1.--Agitator and shaft in raised position.
Figure 2.--Mixer in normal position.
Figure 3.--Mixer and vessel ready for operation.
Figure 4.--Drawing of side and end views of mixer.
Figure 5.--Details of agitator disk, top and side views.
-% .t. I~
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__. H P HEAVY DUTY MOTOR
/--~~~~_ _ _ to ________ ____ c -I N.
.......- BRA5 COLLAR .
/ / HINGED HERE __
.= C COLLAR _:!'- o______
-------. -- t AGITATOR -
FIG. 1 T
UNIVERSITY OF FLORIDA
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