Parr Instrument 1108P - Manual (Page 13)

w w w . p a r r i n s t . c o m 13
1108P Oxygen Combustion Vessels
1. Assemble the bomb with the head in the cyl-
inder and count the number of turns required
to bring the screw cap down firmly against the
head.
2. Then open the bomb; remove the head and
replace the screw cap, but turn it down to only
one-half of the turns previously counted. This
will usually be about four turns.
3. With the screw cap in this position, use a dial
gage to measure the vertical deflection when
lifting the screw cap upward. If this measure-
ment exceeds 1/32 inch (0.030”), the screw cap is
unsafe and should be discarded.
4. The cylinder can then be returned to the fac-
tory for inspection. If the threads on the cylinder
are in good condition, a new screw cap can be
custom-fitted to the cylinder.
Never under any circumstances use oil on the O-
rings which seals the bomb head or on any of the
valves or fittings which handle compressed oxygen.
This precaution applies to all of the oxygen bombs
parts to the oxygen filling connection as well.
Although Parr oxygen bombs are made from alloys
which will withstand most corrosive gases, these
bombs will not resist chlorine, fluorine or bromine
in the presence of moisture. If samples yielding
appreciable amounts of these elements are burned
in a Parr bomb, the interior surfaces may become
etched or corroded. In such cases the bomb should
be emptied and washed as quickly as possible after
each combustion.
If the interior of the bomb should become etched
as mentioned above, the resistance of the metal
to further attack can be improved by restoring the
surface to its original highly polished condition.
Bombs needing repolishing or other repair work can
be returned to the factory. A periodic overhaul and
test at the factory will help to keep any Parr oxygen
bomb in first-class condition.
See page 14 for a Maintenance Checklist.
Bomb Repairs and Proof Tests
The 20VB valve seat, 230A, 415A, and the four 238A
O-rings should be replaced after every 500 firings,
or every six months, whichever occurs first. If the
bomb is used for samples containing chlorine, these
repairs should be made after every 250 firings.
Parr oxygen bombs can be returned at any time for
repair and testing. A factory test is recommended
after every 5000 firings, or after any of the following
conditions; (a) fired with an excessive charge, (b)
ignition of any internal components, (c) machined
by any source other than the factory, (d) damaged
by corrosive vapors that might have exceeded 80%
of the corrosion allowance, or (e) any changes in the
threads on the bomb cylinder and/or screw cap.
When returning a vessel to the factory, ship it to:
Parr Instrument Company
Attn: Repair Department
211- 53rd Street
Moline, Illinois 61265
A purchase order covering the repair work should be
included with the shipment or mailed to the same
address as no repairs will be started without specific
instructions. Be sure to include a return shipping
address and the name and telephone number of the
individual to be contacted if questions arise con-
cerning excessive repair costs or other problems.
Individual repair parts can be ordered from any Parr
dealer or direct from the factory.