Parr Instrument 6300 - Manual (Page 31)

O
PERATING
I
NSTRUCTIONS
6300
5
w w w . p a r r i n s t . c o m 31
C
LOSING THE
B
OMB
Care must be taken not to disturb the sample when
moving the bomb head from the support stand to the
bomb cylinder in the calorimeter. Check the sealing
ring to be sure that it is in good condition and moisten
it with a bit of water so that it will slide freely into the
cylinder.
Notice that the bomb head grounding lug extends
beyond the outside diameter of the bomb head. A slot
for this lug is cut into the top of the calorimeter bucket
which holds the bomb cylinder. Position this lug ap-
proximately 20 degrees to the operators right and slide
the head into the cylinder and push it down as far as it
will go. Now rotate the bomb head 20 degrees to the left
until the lug contacts the left edge of the cut out and is
pointed to the front of the calorimeter.
F
ILL
C
YCLE
Once the calorimeter is started and the cover is closed,
the fill sequence begins (see Figure 5-1).
The calorimeter checks the bomb ignition circuitry 1.
for continuity.
The water fill solenoid opens and water is pumped 2.
from the closed water supply tank into and through
the bucket that surrounds the bomb. Overflow from
the bucket is returned to the closed water tank.
Because the jacket and bucket are both filled with
water from the closed water tank, initial equilibrium
will be reached quickly.
The oxygen fill solenoid is opened and oxygen is 3.
added slowly to the bomb to bring its pressure to
approximately 30 atm.
P
RE
-P
ERIOD
At the completion of the fill sequence, the pre-period
begins (see Figure 5-3).
The water fill solenoid valve closes and isolates the 1.
water in the bucket from the rest of the system.
Water within this bucket is circulated by the stirrer.
Water continues to circulate from the closed water
system through the jacket surrounding the bucket.
The oxygen filling valve closes and the pressure in
2.
the filling line is vented. The automatic check valve
at the top of the bomb closes and isolates the bomb
from the oxygen filling line.
The controller monitors the operating temperature 3.
until it confirms that the initial equilibrium has been
established.
B
OMB
F
IRING
Once the initial equilibrium is confirmed, the controller
initiates the firing sequence.
There are no changes to the circulation pattern, as
shown in Figure 5-3, from the pre-period through the
bomb firing and post-period.
A warning of five short beeps is sounded indicating 1.
the bomb is about to be fired.
Current is passed through the electrical leads to 2.
ignite the ignition thread.
The controller monitors the temperature in the 3.
bucket to establish that a temperature rise actually
occurs. If no temperature rise occurs, the misfire
message is displayed on the controller and the abort
sequence is initiated.