TM 5-6640-212-14
(6)
Read the weight directly from the beam
2-46. Color Comparator.
by adding the amount indicated on upper and lower
a. Description. The color comparator, designed to
beams.
comply with the requirements of ASTM Method D2392
(7)
When weighing above the beam
(TM 10-1166), is stored in drawer D5 (figs. 1-2 and B-
capacity, place the additional weights on the right
10). It is used to determine the acceptability of color of
platform until the total of these weights comes to within
dyed aviation gasoline by comparing the hue and color
the beam capacity range of the weight of the specimen.
intensity of the dyed sample to glass permanent color
The final balance is done by means of the poises. The
standards. The device includes a split field color
weight of the specimen is represented by the total of the
comparator that provides for simultaneous viewing of the
weights on the right platform plus the weight indicated on
dyed gasoline sample and the glass color standard
the beams.
disks, glass fluid tubes of 200-mm viewing depth, and
fluid-type plungers made of polished optical glass. The
2-48. Aneroid Barometer.
reference fluid used in the color comparator may be
a. Description. The aneroid barometer (fig. 2-35),
either distilled water or a sample (without dye or lead
designed to comply with the requirements specified in
alkyl fluid additives) of the gasoline to be tested.
ASTM Method D86 (TM 10-1166), is wall mounted on
b. Operation. Refer to ASTM Method D2392 (TM
the left side of the laboratory above the kinematic
10-1166) for detailed test procedures.
viscosity bath. It is a temperature compensated
2-47. Double Beam Balance.
instrument and is graduated in both English and metric
systems, from 26 to 31 inches (166 cm to 78.7 cm) of
a. Description. The double beam balance is
mercury. Pressure graduation is 0.10 inch (0.25 cm) of
located in drawer C5 (figs. 1-2 and B-10). It is used to
mercury. It can be used for altitudes from sea level to
measure chemicals to be used in the various testing
3500 feet (1057.5 m).
procedures. The upper beam is graduated from zero to
b. Operation.
10 grams in 0.1 gram divisions. The lower beam is
graduated from zero to 200 grams in 10 grams divisions.
(1)
The basic unit used in the aneroid
The capacity of the balance is 200 grams and may be
barometer is a round thin metal box fitted inside a clamp
increased through the use of weights. A set of weights in
in the form of a C-spring. The metal box, or bellows, is
a case, from 1 to 1000 grams, is stored in drawer D3 (fig.
sealed after practically all of the air has been removed.
B-9).
At this point the bellows would collapse due to the air
b. Operation.
pressure pushing against it from the outside. The C-
spring keeps the bellows from collapsing since it holds
(1)
Set each poise at the zero mark.
the sides of the metal box apart and in balance. Changes
(2)
If balance scale is not balanced at zero,
in air pressure disturb this point of balance in respect to
make the necessary corrections with the two knurled
the atmosphere and each slight movement is transmitted
nuts on front of the beam; then lock the nuts against
to the barometer pointer which is positioned over a dial
each other to prevent any movements.
graduated in one-tenth of an inch of mercury.
NOTE
(2)
Figures on dial 26 through 31, represent
Always check zero balance before
inches of mercury, the standard means of expressing
each use.
atmospheric pressure. Read the indicating hand closet to
the dial which responds readily to any change in
(3)
Place the specimen to be weighed on
atmospheric pressure. Use the set hand to note any
the left platform of the balance.
change in pressure. Position the set hand directly over
(4)
Move the lower poise to the right until
the indicating hand. A few hours after setting, note any
the first notch is reached which causes the right platform
change in pressure. A rise in pressure is indicated by
to drop. Move poise back one notch. This should cause
movement of the indicating hand to the right. A fall in
the right platform to rise again.
pressure is indicated by movement of the indicating hand
(5)
Move the upper poise to the right until
to the left.
the scale is brought into balance, with pointer in center of
the dial or swinging an equal distance to left and right.
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