Parr Instrument 6300 - Manual (Page 46)

9
M
AINTENANCE
& T
ROUBLESHOOTING
P a r r I n s t r u m e n t C o m p a n y 46
500 Tests (Continued)
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 and
is positioned between the bucket and the air-can of the
calorimeter. For your convenience, these parts may be
purchased as kit number 6038, Firing Maintenance Kit.
See Figures F-1 and F-2 for O-ring locations.
Lubricate the 659DDJU and 357HCJB O-rings in the
bomb release cylinder with 811DD lubricant. See
Figures F-20 for O-ring locations. Clean the ignition
contacts.
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, 1138DD, 969DD, 1143DD and 357HCJB
O-rings with 811DD lubricant. Tools required are:
screwdriver, snap ring pliers and needle nose pliers.
Turn off the gas supply to the calorimeter. Go to 1.
the Diagnostics Screen and turn on the bomb seal
command. Raise the lid and turn ON the O
2
Fill
Command. These steps are necessary to release the
gas pressure in the seal/release mechanism before
disassembling.
Turn off the calorimeter, once the oxygen has
2.
depressurized.
Insert the bomb head into the cylinder and lock into
3.
place.
Disengage the screws, SA1632RD018 that hold the
4.
bucket in the air can. Remove the 941DD plastic
wedge that secures the front of the air can assembly.
Lift the bomb and bucket as a unit from the calo-
5.
rimeter air can chamber and disconnect the bucket
thermistor probe. Set this unit aside.
Remove the vessel spacer, 964DD and the associ-
6.
ated O-ring, 969DD.
Remove the cylinder spacer, 1141DD, which sits on
7.
top of the snap ring, 1137DD.
Remove the snap ring that retains the cylinder insert
8.
in the release mechanism at the bottom of the air
can.
Withdraw both the insert and the release pin as a
9.
unit using needle nose pliers.
Remove any scoring on the release pin, above the
10.
smaller O-rings, 659DDJU in present with crocus
cloth. Replace the O-rings on the 966DD2 release
pin as well as the 1138DD O-ring that seals the
cylinder insert. Lubricate 659DDJU and 357HCJB
O-rings with 811DD lubricant.
Reverse the above procedure to reinstall the cylin- 11.
der insert/pin as well as the bomb bucket assembly.
Make sure that the large side hole in the 1139DD
insert is oriented toward the left side of the instru-
ment. The insert is keyed to the cylinder and can
not be fully inserted unless it is properly oriented.
5000 Tests
To deal with the realities of today’s test loads and cycle
times, the ASTM Committee recommends in method
E144 - 94(2006)e1 that “all seals and other parts that
are recommended by the manufacturer be replaced or
renewed after each 5000th firing or a more frequent
interval if the seals or other parts show evidence of
deterioration”. Oxygen bombs returned to Parr for
service will be tested in accordance with ASTM E144
- 94(2006)e1. A test certificate is provided with each
repair.
This service includes:
Disassembly, cleaning and inspection of all parts •
Re-polishing of the inner surfaces of the bomb •
Re-assembly with new insulators, and seals, sealing •
rings, and valve seats
Proof testing
•
Hydrostatic testing •
The hydrostatic and proof testing of the oxygen bomb
should be performed after every 5000 firings or if:
The bomb has been fired with an excessive charge. •
The ignition of any of the internal components has •
occurred.
There have been any changes in the threads on the
•
bomb cylinder.
The bomb has been machined by any source other
•
than Parr Instrument Company.
After repeated use with samples high in chlorine (over
1%), the inner surfaces of the bomb will become etched
to the point where appreciable amounts of metal salts
will be introduced during each combustion. Any bomb
which is being used for chlorine determination should
be polished at more frequent intervals to prevent the
development of deep pits. If the interior of the bomb
should become etched or severely pitted, the resistance
of the metal to further attack can be improved by
restoring the surface to its original polished condition.