Parr Instrument 6400 - Manual (Page 68)

6400
Calorimeter Instruction Manual
9-3
50 to 100 Test Maintenance
Replace the heating wire, with 2” of 840DD2. Wind the wire 360 degrees
clockwise around screws. Clean the 986DD Electrode Contact Pins with a mild
abrasive, such as a pencil eraser. Clean the bomb head electrode points in a
similar fashion and tighten the screws holding the heating wire in place.
500 Test Maintenance
Clean the ignition contacts.
Under normal usage Parr oxygen bombs will give long service if handled with
reasonable care. However, the user must remember that these bombs are continually
subjected to high temperatures and pressures which apply heavy stresses to the sealing
mechanism. The mechanical condition of the bomb must therefore be watched carefully
and any parts that show signs of weakness or deterioration should be replaced before
they fail.
For your convenience, these parts may be purchased as kit number 6038, Firing
Maintenance Kit.
Parr recommends that the following parts on the oxygen bomb be changed every 500
tests or six months whichever comes first: 840DD2, 1374HCJV (2), 394HC, 821DD (1),
1071DD, 1444DDJB, 659DD, 519AJV, 694DD. See Figures 10 and 26 for parts
locations. When reassembling the bomb head, take care not to roll the 694DD o-ring as
this will cause an oxygen leak.
Note:
Samples that contain chlorine or are abrasive may require this
maintenance to be performed on a more frequent interval such as every
250 tests.
The 882DD and 969DD o-rings should also be replaced. See Figures 23 and 24 for o-
ring locations.
The 1140DD Seal/Release mechanism should be serviced with the same frequency as
the bomb head. This includes the replacement and lubrication of the 659DDJU (2),
1138DD, 1143DD and 357HCJB o-rings with 811DD lubricant. See Figure 24 and
Figure 25 for o-ring locations. The tools required are: screwdriver, snap ring pliers and
needle nose pliers.
1. Turn off the gas supply to the calorimeter. Disconnect the oxygen connection to the
back of the calorimeter. Go to the Diagnostics Screen and turn on the bomb seal
command. These steps are necessary to release the gas pressure in the seal/release
mechanism before disassembling.
2. Turn off the calorimeter.
3. Insert the bomb head into the cylinder and lock into place.
4. Disengage the screws, SA163X2RD018 that hold the bucket in the air can. Remove
the 941DD plastic wedge that secures the front of the air can assembly.
5. Lift the bomb and bucket as a unit from the calorimeter air can chamber and
disconnect the bucket thermistor probe. Set this unit aside.
6. Remove the vessel spacer, 964DD and the associated o-ring, 969DD.