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Page Title:
Endurance test acceptance criteria |
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|  MIL-P-17881D(SHIPS )
minus 0F of maximum specified liquid temperature. The pump shall be operated
plus
at one third, two thirds and rated capacity in approximately equal time intervals. Operations
at rated capacity shall be at minimum specified net positive suction head available, or
maximum specified suction lift or vacuum, as applicable.
4.3.3.1.4 The pump shall be monitored during the endurance test to accurately record
the conditions of operation, the capacity delivered, the total head developed, the speed at
which operated and the general performance observed. Data shall be collected and the pump
inspected at least twice per day of operation. For each periodic inspection, in addition
to all measured data, the record shall indicate the following:
The pump seal or packing leakage rate.
(a)
The temperature of the grease and oil-lubricated bearings, ambient air
(b)
temperature, and pumped fluid temperature.
The airborne noise level (normal-abnormal).
(c)
The vibration level (normal-abnormal).
(d)
The smoothness of operation (normal-abnormal).
(e)
All other abnormal findings.
(f)
All adjustments made.
(g)
Changes made in the conditions or method of operation.
(h)
Endurance test acceptance criteria:
4.3.3.1.5
#
The head-capacity curve at maximum rated speed after 500 hours of pump opera-
(a)
tion shall conform to the specification requirements and shall show no
abnormal deviations from the curve before the 500 hour test.
The unit performance and operation after 500 hours of operation shall be
(b)
unchanged and normal and meet all specification requirements.
The unit operation at the end of the l ndurance test shall be smooth and shall
(c)
exhibit noise and vibration levels that are normal and in conformance with
the specification.
Lubrication shall have remained satisfactory throughout the test period.
(d)
Bearing temperatures shall have remained normal and within the limits
specified and shall be consistent with their respective bearing clearances
and oil and grease limitations.
The pump, mechanical seal or packing shall have performed as specified. The
leakage rate shall not exceed 5 drops per minute for mechanical seals or
that recommended by the supplier for packed pumps throughout the test.
All running clearances shall be normal.
(f)
All components subject to attack from corrosion, erosion, cavitation, etc.
(g)
shall be in an acceptable condition commensurate with 500 hours of service.
Wear rates for wearing parts, critical for proper operation shall show a rate
(h)
of wear for the test period that shall be consistent with the specified
.
design life requirements.
No failures shall have occurred throughout the 500 hour test.
(i)
4.3.3.1.6 Post endurance test
The unit subjected to the 500 hour endurance
#
teat shall be restored to the as-new conditon by replacement of all parts worn beyond the
as-new design tolerances. The restored unit shall successfully pass the shop test; speci-
fied in 4.3.1.1, 4.3.1.3(a) end 4.3.1.4 if applicable. The shop test documentation and
completed part examination check list shall indicate that the unit was subjected to the
l ndurance test and subsequently restored and shop tested and that it shall be certified as
fully conforming to the specification for unrestricted service.
4.3.3.2 Shock test. The pump shall undergo a shock test to ascertain that the pump
has the necessary shock resistance. The shock test shall be performed in accordance with
MIL-S-901 and the specific shock test requirements (see 6.1).
4.3.3.2.1 Before and after the shock test the pump and driver and other components
susceptible to internal derangement shall be disassembled to the l xtent necessary and the
critical dimensions and running clearances measured, calculated, end recorded. During this
disassembly the critical components and assemblies subject to shock damage and derangements
shall be identified and listed in the inspection record end after completion of the test the
condition of l ach component and assembly determined and recorded. Shafts, impellers and
turbine rotors shall be inspected by one of the l pplicable non-destructive test procedures,
other than radiography specified in MIL-STD-271.
4.3.3.2.2 Before end after the shock test, shop tests in accordance with 4.3.1.3 shall
be performed to determine the changes in performance characteristics of the pump. Vibration
measurements shall be taken at the bearing caps or housings of the pump and driver at equal
speeds during the initial and final capacity test to determine the changes in mechanical
operation.
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