Parr Instrument 1108P User Manual
1108P
Oxygen Combustion Vessel
Operating Instruction Manual
418M
1108P Oxygen Combustion Vessels
Preface 3
Scope 3
Related Instructions 3
Customer Service 3
Operating the 1108P Oxygen Combustion Vessel 4
Precautions 4
Special Alloy Construction 4
A Chlorine-Resistant Bomb 4
1108BP Oxygen Combustion Vessel 4
Other Special Purpose Bombs 4
Allowable Sample Size 5
Attaching the Cotton Thread 5
Liquids in the Bomb 5
Closing the Bomb 5
Filling the Bomb 6
Firing the Bomb 6
Recovering the Combustion Products 7
An Optional Recovery Procedure 7
Operating Suggestions 11
Poor Combustion 11
Oxygen Charging Pressure 11
Maintenance and Safety Instructions 12
Bomb Maintenance 12
Bomb Repairs and Proof Tests 13
1108P Maintenance Checklist 14
Parts 16
1108P Parts Diagram Key 16
Complete Assemblies 16
Parts for the 1108P Oxygen Combustion Vessel 17
Parts for the 2901 Ignition Unit 18
Parts for the 1825 Oxygen Filling Connection 19
Samples and Sample Holders 8
Particle Size and Moisture Content 8
Combustion Aids 8
Sample Pellets 8
Combustion Capsules 8
Foodstuffs and Cellulosic Materials 9
Coarse Samples 9
Corrosive Samples 9
Liquid Samples 9
Gelatin Capsules 9
Tape-Sealed Sample Holders 10
Heavy Oils 10
Explosives and High Energy Fuels 10
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Parr Instrument Company
1108P Oxygen Combustion Vessels
Preface
Scope
These instructions cover the procedures to be followed when using a Parr 1108P Oxygen Combustion
Vessel to determine calorific values of solid or liquid
combustible material in a Parr calorimeter, or when
using an 1108P Vessel in a 1901 Oxygen Bomb Apparatus to prepare solid or liquid samples for chemical
analysis. The user should study these instructions
carefully in order to obtain a complete understanding of the capabilities and limitations of an 1108P,
and to be well aware of the precautions to be observed in its operation. Calorimeter operations and
the operation of various oxygen bomb accessories
are described in separate instruction manuals listed
below, copies of which are available upon request.
Related Instructions
No. Description
201M Limited Warranty
207M Analytical Methods for Oxygen Bombs
230M Safety in the Operation of Laboratory
and Pressure Vessels
483M Introduction to Bomb Calorimetry
Note About Nomenclature:
Historically, burning a sample enclosed in a
high pressure oxygen environment is known
as Oxygen Bomb Calorimetry and the vessel
containing the sample is known as an Oxygen
Bomb. The terms bomb and vessel are used
interchangeably.
Customer Service
Questions concerning the installation or operation of this instrument
can be answered by the Parr Customer Service Department:
1-309-762-7716 • 1-800-872-7720 • Fax: 1-309-762-9453
E-mail: parr@parrinst.com • http://www.parrinst.com
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1108P Oxygen Combustion Vessels
Operating the 1108P 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 materials 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 submerged in water.
• Do not ignite a volatile sample without using
one of the sealed sample holders described on
pages 8-10.
Special Alloy Construction
The standard 1108P 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 combustion. 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 produced when burning samples containing halogen
compounds. For these applications, Parr offers the
1108PCL described below. It should be noted that
all instructions for the 1108P apply equally to the
1108PCL as well.
A Chlorine-Resistant Bomb
The 1108PCL is the same as the standard 1108P
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 1108PCL instead of 1108P for its longer
service life under extreme corrosive conditions.
Bomb maintenance is also improved. In most cases,
1108PCL Oxygen Combustion 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.
• Stand away from the bomb during and do not
handle the bomb for at least 6 minutes after firing.
• Keep the bomb in good condition at all times.
Any parts that show signs of weakness or deterioration must be replaced promptly.
• Read the maintenance and safety instructions
beginning on page 12 before starting to use the
bomb, and urge all operating personnel to reread 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.
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Parr Instrument Company
1108BP Oxygen Combustion Vessel
The 1108BP and 1108BPCL Combustion Vessels are
identical to the 1108P and 1108PCL models except
for the screw cap and cylinder. The 1108BP and
1108BPCL have a heavy duty screw cap allowing for
higher energy release per sample. The cylinder has
been adapted to comply with Indian Standard IS 1350.
Other Special Purpose Bombs
Although the 1108P and 1108PCL will handle a broad
range of test samples, Parr also offers other special purpose combustion bombs, including: a high
pressure bomb for explosives, an oversize bomb
for large samples and a semi-micro bomb for small
samples. Separate operating instructions are issued
for these special bombs.
1108P Oxygen Combustion Vessels
845DD2 Cotton Ignition Thread
To attach the fuse either twist or tie the cotton thread
to the A40DD2 semi-permanent fuse wire.
Allowable Sample Size
To stay within safe limits, the bomb should never be
charged with a sample which will release more than
8000 calories when burned in oxygen, and the initial
oxygen pressure should never exceed 40 atmo-
spheres (590 psig). This generally limits the mass of
the combustible charge (sample plus benzoic acid,
gelatin, ring oil or any combustion aid) to not more
than 1.1 grams. When starting tests with new or
unfamiliar materials it is always best to use samples
of less than 0.7 of a gram, with the possibility of
increasing the amount if preliminary tests indicate
no abnormal behavior. To avoid damage to the
bomb and possible injury to the operator, it should
be a standing rule in each laboratory that the bomb
must never be charged with more than 1.5 grams of
combustible material.
Attaching the Cotton Thread
A cotton thread (845DD2) is used as an auxiliary
fuse to ignite the sample. Ten centimeters of thread
is recommended for this auxiliary thread which is
looped over the heating wire, doubled on itself,
twisted to form a single strand and fed into the
sample cup to lay on the sample.
When contact is made through the heating wire,
the thread will ignite, drop into the sample cup and
ignite the sample.
A38A Head Support & Stand
Set the bomb head on the A38A support stand when
attaching the fuse and arranging the sample.
Liquids in the Bomb
Most bomb combustion procedures call for a small
amount of liquid to be placed in the bottom of the
bomb as a sequestering agent and absorbent. If the
amount and type of liquid are not otherwise specified, add 1.0 mL of distilled or deionized water from
a pipet.
Closing the Bomb
Care must be taken not to disturb the sample when
moving the bomb head from the support stand to
the bomb cylinder. 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;
then slide the head into the cylinder and push it
down as far as it will go. For easy insertion, push
the head straight down without twisting and leave
the gas release valve open during this operation. Set
the screw cap on the cylinder and turn it down firmly by hand to a solid stop. When properly closed, no
threads on the cylinder should be exposed. If the
screw cap tends to bind to the cylinder at this point,
indicating that it might be difficult to open the
bomb after it has been fired, turn the screw cap back
slightly – but only a few degrees – enough to release
the binding, since the bottom thread must remain
fully engaged. It is not necessary to use a wrench or
spanner on the screw cap. Hand tightening should
be sufficient to secure a tight seal.
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1108P Oxygen Combustion Vessels
Filling the Bomb
The instructions below describe a manual system us-
ing the 1825 Oxygen Filling
Connection furnished with
other Parr apparatus.
Oxygen for the bomb can
be drawn from a standard
commercial oxygen tank.
Unscrew the protective cap
from the tank and inspect
the threads on the valve outlet to be sure they are clean
and in good condition. Place
the ball end of the connection into the outlet socket
and draw up the union nut
tightly with a wrench, keep-
ing the 0-55 atm gage in an
upright position.
The pressure connection to the bomb is made with
a slip connector on the oxygen hose which slides
over the gas inlet fitting on the bomb head. Slide
the connector onto the inlet valve body and push it
down as far as it will go. If it does not slide easily,
a drop of water spread around the inlet valve will
lubricate the sealing rings.
Close the outlet valve on the bomb head; then open
or “crack” the oxygen tank valve not more than
one-quarter turn. Open the filling connection control
valve slowly and watch the gage as the bomb pressure rises to the desired filling pressure (usually 30
atm., but never more than 40 atm.); then close the
control valve. The bomb inlet check valve will close
automatically when the oxygen supply is shut off,
leaving the bomb filled to the highest pressure in-
dicated on the 0-55 atm. Gage. Release the residual
pressure in the filling hose by pushing downward
on the lever attached to the relief valve. The gage
should now return to zero. If the pressure drops
slowly and a large amount of gas escapes when the
pressure relief valve is opened, the check valve in
the bomb head is not operating properly. This trouble will have to be corrected before the bomb can
be used. If too much oxygen should accidentally be
introduced into the bomb, DO NOT proceed with the
combustion. Detach the filling connection; exhaust
the bomb; remove the head and reweigh the sample
before repeating the filling operation.
1825 Oxygen Filling
Connection
Firing the Bomb
The electric current for
firing the bomb should
be drawn from a Parr
2901EB Ignition Unit
connected to an 115V
50/60Hz grounded electrical outlet. (For 230V
50/60Hz use a 2901EE
Ignition Unit). Connect
one of the lead wires
from the calorimeter
to the 10 cm binding
post on the ignition unit
and the 2nd wire to the
middle or “common”
terminal.
When using the bomb in a calorimeter, insert the
421A lifting handle into the two holes in the side of
the screw cap and lower the bomb partially into the
calorimeter water bucket. Press the banana plugs
on the two ignition wires firmly into the terminal
sockets on the bomb head before the head is completely immersed in the water. After connecting
the wires, lower the bomb into the bucket with its
feet spanning the circular boss in the bottom of the
bucket. Remove the lifting handle and shake off any
drops of water back into the bucket. Be careful not to
remove any water from the bucket with the fingers.
When using the bomb alone for analytical purposes
it should be connected to the ignition unit as described above and held submerged in an A387A or
similar water bath during firing.
In all operations, check the bomb for leaks before
firing. If any gas leakage is indicated, no matter how
slight, DO NOT FIRE THE BOMB. Instead remove it
from the water bath; release the pressure and eliminate the leak before proceeding with combustion
test. If no leakage is indicated, then stand back and
press the firing button on the ignition unit to fire the
charge.
Caution!
Do not have the head, hands or any parts of
the body directly over the bomb during the
firing period and do not go near the bomb for
at least 20 seconds after the firing.
2901 Ignition Unit
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Parr Instrument Company
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