TM 5-6640-212-14
NOTE
If a tared weighing boat is used,
remove the tare ring and zero with
the empty boat on the pan.
(11) To weigh to a preset weight, adjust the weight
control knobs and, if necessary, the micrometer drum
knob to the desired value. Preweigh, following steps (9)
(a) through (c), move the arresting lever to the full
release position, and adjust the volume by use of filter
paper or a glass rod until the value is reached.
(12) The weighing results can be corrected for
conditions requiring absolute weighings. The switching
weights are made on noncorrosive nonmagnetic steel
having a density of 7.88 grams per milliliter. For a
medium air density of 0.0012 grams per milliliter, they
are adjusted to match brass weights of density 8.4 grams
per milliliter.
Differential weighing of the same material do not require
correction. In case of absolute weighings, the result of
the following formula has to be added to the weighing
result.
COKn (1.10-5 (PL/PG) + (PL/PP) grams where
n
= reading of the balance in grams
PL = the density of the air in grams per milliliter
PG = the density of the switching weights in
grams/milliliter
PP
=the density of the weighing material in
grams/milliliter
2-24. Distillation Test Apparatus.
a. Description. Two distillation units (fig. 2-23) are
Figure 2-22. Arrestment Lever Positions
located above drawer L1 (fig. 1-2). Each unit is
designed to comply with the requirements specified in
(c) After obtaining a volume of 0.1 gram, remove
ASTM Method D86 (TM 10-1166) in the distillation of
the container from the double beam balance and place it
petroleum products. The righthand unit incorporates a
on the pan of the analytical balance. (Tongs should be
500-watt immersion heater for gas oils. Each unit
used).
consists of a shield assembly and a condenser
assembly. The shield and condenser exteriors are
(d) Adjust the volume by use of filter paper or a
constructed of stainless steel; the condenser interior of
glass rod.
copper insulated with a 1-inch thickness of fiberglass.
The ice-refrigerated condenser is equipped with a drain
(10) To tare containers over 1 gram, weigh the
and overflow outlet, and distilled oil outlet. The shield
container as noted above for any unknown weight.
incloses a 750-watt heater with autotransformer, two
After taring, if it is desired to fill the container with a
porcelain refractory blocks, observation window, an
specific volume, adjust the zero control knob to reflect
elevating device to allow proper alinement of distillation
zero on the optical scale, leaving the macro scale
flask to condenser tube, a temperature control assembly,
untouched. Proceed as in (9) (a) through (c) above, and,
and an ONOFF toggle switch. Wood blocks are stored
by use of filter paper or a glass rod, adjust to the specific
in drawer K1 (fig. B-16) for supporting cooling jar and
volume desired by accounting for the macro weight
graduate. Asbestos boards and covers are stored in
figure only.
drawer K1.
2-41
