Parr Instrument Series 4520 - Manual (Page 19)

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4520 Bench Top Reactors Parr Instrument Company
PERIODIC PRESSURE TESTS
Each cylinder used in a Parr stirred
reactor is tested under hydrostatic pressure
to 1.3 times its maximum rating before it is
released from the factory. Micrometer
caliper measurements are taken during this
test to check the deflection of the walls
under pressure. Excessive deflection or
failure of the metal to resume its original
dimensions after pressure is released
indicates that a cylinder is potentially unsafe
and it will be rejected. Similar tests should
be made at regular intervals during the life of
each cylinder, and particularly whenever the
user suspects that the equipment has been
over-stressed or damaged.
Some laboratories maintain hydraulic
test facilities and make it a rule that all
pressure vessels must be tested at regular
intervals. Records are kept of deflections at
specific test pressures so that any increase
in deflection becomes a warning that the
metal has lost strength. Any cylinder that
fails to return to its original dimensions after
application of the prescribed hydrostatic test
should be discarded as unsafe for further
use.
Users who do not have pressure test
facilities can return any Parr pressure vessel
to the factory for hydrostatic testing and
overhaul. This should be done whenever
the metal shows excessive damage from
corrosion or whenever an over-pressure or
other unusual occurrence raises any safety
questions. To return a vessel for repair
contact Parr Instrument Company for a
return authorization number. Apparatus
returned for testing and overhaul should be
shipped prepaid to the Parr Instrument
Company, 211-53rd Street, Moline, Illinois
61265. An order or letter of instructions
should be mailed to the same address, as
no repair work will be started without specific
instructions and a Health & Safety
Assurance Certification form (F0042) signed
by a responsible user.