Parr Instrument Series 4550 - Manual (Page 17)

4550 Floor Stand Reactors
w w w . p a r r i n s t . c o m 17
Periodic Pressure Tests
Each cylinder used in a Parr stirred reactor is tested
under hydrostatic pressure to the higher of 1.43
times the rated working pressure at room tem-
perature or 1.30 times the rated working pressure
corrected for temperature 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 po-
tentially 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 ques-
tions. To return a vessel for repair, contact Parr
Instrument Company for a return authorization
number. Apparatus returned for testing and over-
haul should be shipped prepaid to 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 (FX004) signed by a
responsible user.