Parr Instrument 1108R - Manual (Page 4)

P a r r I n s t r u m e n t C o m p a n y 4
1108R Oxygen Combustion Vessel
Operating the 1108R Oxygen
Combustion Vessel
Precautions
Combustion with oxygen in a sealed bomb is a very
effective and reliable method for releasing all heat
energy obtainable from a sample and for preparing
hydrocarbon compounds and carbonaceous materi-
als for analysis, but there are certain precautions
which must always be observed when using this
equipment. In particular:
• Do not overcharge the bomb with too much
sample or with a sample which might react with
explosive violence.
• Do not overcharge the bomb with too much
oxygen. The initial charging pressure should not
exceed 40 atm (590 psig).
• Do not fire the bomb alone on an open bench
without providing a protective cooling medium.
The bomb should be completely submerged in
water during firing.
• Do not fire the bomb if gas bubbles are released
from any point on the bomb when it is sub-
merged in water.
• Do not ignite a volatile sample without using
one of the sealed sample holders described on
page 9 or the tape technique.
• Stand away from the bomb during and do not
handle the bomb for at least 6 minutes after fir-
ing.
• Keep the bomb in good condition at all times.
Any parts that show signs of weakness or dete-
rioration must be replaced promptly.
• Read the maintenance and safety instructions
beginning on page 10 before starting to use the
bomb, and urge all operating personnel to re-
read these instructions often.
• Screw caps and cylinders are stamped so that
each cylinder and screw cap can be identified as
a matched set. We recommend that you maintain
the match of cylinders and screw caps for your
safety and ease of use.
Special Alloy Construction
The standard 1108R Oxygen Combustion Vessel is
made of a special niobium-stabilized stainless steel
selected for it’s excellent resistance to the mixed
nitric and sulfuric acids generated in a bomb com-
bustion. It is a superior alloy which will withstand
the conditions generated in almost all fuel testing
applications, yet neither it nor any other stainless
steel will resist the corrosive atmospheres pro-
duced when burning samples containing halogen
compounds. For these applications, Parr offers the
1108RCL Combustion Vessel described below. It
should be noted that all instructions for the 1108R
apply equally to the 1108RCL as well.
A Chlorine-Resistant Bomb
The 1108RCL Combustion Vessel is the same as the
standard 1108R model, but with a head and cylinder
made of an alloy with superior corrosion resistance
to the free chlorine and halogen acids released when
burning chlorinated samples. Users who analyze
waste materials and combustible solvents are urged
to select the 1108RCL Combustion Vessel instead
of 1108R for its longer service life under extreme
corrosive conditions. Bomb maintenance is also
improved. In most cases, 1108RCL vessels returned
to the factory for scheduled maintenance can be
restored to optimum finish by polishing instead of
having to rebore the cylinder to remove pits.
Other Special Purpose Bombs
Although the 1108R and 1108RCL Combustion
Vessels will handle a broad range of test samples,
Parr also offers other special purpose combustion
vessels, including: a high pressure bomb for ex-
plosives, an oversize bomb for large samples and
a semi-micro bomb for small samples. Separate
operating instructions are issued for these special
bombs.