TM 5-6640-212-14
2-17. Gum Bath.
NOTE
Draining of water from the low and
a. Description. The gum bath (fig. 2-10), designed
high pressure boilers will reduce the
to comply with the requirements specified in ASTM D381
(TM 10-1166), is located at the right of the front wall of
possibility of minerals and other
the laboratory. It is used to deter-mine the existent gum
deposits from building onto critical
in petroleum products. Included with the gum bath is an
parts in the boilers and water feeders
air flow indicator. A pyrometer (para 2-18), a high
which can cause a malfunction over a
pressure steam boiler (para 2-19) and a low pressure
period of time if not flushed. Also in
steam boiler (para 2-20) are used with the gum bath and
temperatures below the freezing mark
are located in the same area. The air flow indicator is
and without heat supplied to
calibrated in pounds and ounces, corresponding to the
laboratory the boilers and pipes
flow of air in liters per second. The rate of flow required
containing water can burst.
is 1 liter per second plus or minus 15 per-cent. The
normal reading of 1 liter per second is indicated by the
(5) Proceed with the test in accordance with the
black graduations on indicator, and the plus or minus 15
procedures of ASTM Method D381 (TM 10-1166).
percent variation is indicated by red graduations. The
pyrometer is an indicating and controlling device for gum
2-18. Pyrometer.
bath preset temperatures. The high pressure steam
boiler is a circulation heater used to raise the
a. Description. The pyrometer (fig. 2-10), designed
temperature of steam supplied to the gum bath for steam
to comply with the requirements specified in ASTM D381
jet evaporation of turbine fuels.
(TM10-1166), is mounted above the gum bath area. It is
used with the gum bath. The pyrometer is an indicating
b. Operation.
and controlling device of gum bath preset temperatures.
The INT switch on the gum bath turns the pyrometer on
(1) Apply power to the gum bath.
or off, as required, to maintain the preset temperature.
(2) Adjust air supply until the flow is indicated on the
The upper green pointer on the pyrometer indicates the
black graduations of the flowmeter.
operating temperature. The lower red pointer indicates
(3) Turn on the INT switch on the gum bath that
the temperature to be maintained. A red light is on when
controls the pyrometer and the AUX switch that controls
the gum bath is heating. When desired temperature is
the high pressure steam boiler.
attained, the red light goes off and the green light comes
(4) Before operating gum bath drain any steam or
on.
water that may be in the piping system as follows:
b. Operation.
(a) Close the pressure regulator by-pass valve
(1) Set the red pointer to the desired temperature,
steam open-close valve.
using the knob located below the scale.
(b) Open the drain valve (fig. 2-11, sheet 2) which
(2) Turn the INT switch on the gum bath to the ON
allows water and steam in lines to be flushed to bottom
position.
of semitrailer (fig. 2-11, sheet 3).
(3) The pyrometer will keep the heat on (red light is
(c) When water and steam stop coming out, close
on) until the preset heat is attained. At that time, the
drain valve and open regulated high pressure steam
pyrometer will turn the heat off (red light will go off, green
open-close valve and proceed with test.
light will come on). 2-19. High Pressure Steam Boiler.
(d) When gum bath testing is complete for the day
close all circuit breakers to gum bath, high pressure
a. Description. The high pressure steam boiler (fig.
boiler, and to low pressure boiler, then drain all water
from the high and low pressure boilers by opening the
specified in ASTM D381, (TM 10-1166), is located in the
drain valve (fig. 2-11, sheet 2).
gum bath area. It is a circulation heater used to raise the
temperature of steam received from the low pressure
steam unit located in the front compartment just behind
the gum bath. The high pressure steam boiler is
equipped with a thermostatic control which can be set to
desired temperatures up to 550 degrees F (288 degrees
C). The AUX switch on the gum bath turns the high
pressure steam boiler on or off.
2-20
