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|  MIL-P-23504(Wep)
phosphate as specified in 4.3.4.1 for the pump lubricant and sealing fluid.
The tricresyl phosphate may be processed to remove water.
4.4.7
Endurance: The vacuum pump shall be subjected to an endurance
test of not less than 504 hours. The lubricant and sealing fluid used
throughout this test shall be tricresyl phosphate as specified in 4.3,4.1.
The endurance test time shall be divided as follows:
(a) One hundred and twenty (120) hours of operation with the vacuum
pump inlet and discharge connections open to atmospheric pressure.
(b) One hundred and twenty (120) hours of operation with the vacuum
pump inlet completely blanked off except for a connection to the absolute
pressure measuring device and the discharge open to atmospheric pressure. A
check shall be made to insure that no flow of-air or other gases is entering
the pump inlet during this test.
(c) Two hundred and sixty-four (264) hours of operation with the
vacuum pump inlet pressure maintained between 50 and 500 microns Hg absolute.
4.4.7.1
Test Procedure: The endurance test time shall be accumulated by
continuous operation at rated speed for periods of 12 hours under the speci-
fied conditions followed by shutdown periods of not less than 6 hours. In-
spections, lubrication, minor adjustments, minor repairs, and preventive
maintenance shall be accomplished during the shutdown periods.
4.4.8
Performance Recheck: Following the endurance test run and without
intervening reconditioning other than normal preventive maintenance and
servicing with lubricants, the vacuum pump shall be resubjected to the per-
formance demonstration specified in paragraph 4.4.6. The performance at this
time shall be not less than that specified in Section 3 for a new vacuum pump.
4.4.9
Final Teardown Inspection: The vacuum pump shall be disassembled
as specified in 4.4.5.1 and a critical inspection made of all components to
determine their operability and any damage or undue wear encountered during
the testing.
4.4.9.1
The measurements taken under 4.4.5.1 shall be repeated for com-
parison with the data recorded prior to testing. Wear or distortion which
exceeds the limits established by the manufacturer for new parts shall be
cause for considering the affected parts as having failed to satisfactorily
pass the tests.
4.4.9.2
Ferrous parts shall be resubjected to magnetic particle inspection
(magnaflux) in accordance with MIL-I-6868 and shall exhibit no indicates of
damage attributable to the tests, or they shall be considered as having
failed the tests. Grind checks and subsurface indications of laps, seams,
or other forging defects noted before the test and which have not increased
in size shall not be cause for rejection.
4.4.9.3
Nonmagnetic casting, forgings, and other operating parts shall be
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