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|  MIL-P-17881D(SHIPS)
by calculation or test for the full range of specified operating conditions, and the results
shown on the plot of thrust versus capacity. The effect of rotor position on axial thrust
shall be determined by test on the first pump of a design tested, and the results shown on
the plot of thrust versus capacity.
Acceptance criteria: The thrust bearing axial load for any specified operating con-
dition or possible rotor position shall not exceed that load used as the basis for design
of the thrust bearing.
4.3.2.4 Test reports for the performance evaluation test shall be compiled into a
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single document. The document shall identify the pump by manufacturer's serial numbers of
pump and driver, the contract or order number under which the tests were performed, the
ship or class of ships for which the pump is intended if known, and the letter and date of
test procedure approval. The test compilation document shall be distributed as follows:
(a) TWO to each procuring agency.
applicable.
(b) Two to one of the following, as
Services Region (DCASR) .
Defense Contract Administration
Defense Contract Administration
Services District (DCASD).
Services Office (DCASO).
Defense Contract Administration
(c) Two to design review agency.
#
4.3.3 Design evaluation tests. One pump of each type, design and size complete with
the driver and all appurtenance and controls shall successfully undergo the design evalua-
tion test specified herein. Separate design evaluation tests of the pump proper and the
driver proper are not acceptable. Design changes which in the opinion of the design review
agency may detrimentally affect the reliability of a previously tested and accepted pump
design shall be cause to require new design evaluation tests in part or in full. It shall
be at the discretion of the design review agency to require new design evaluation tests when
an accumulation of several design changes, each of itself apparently not significant to pump
reliability, collectively considered render suspect the validity of any one or all of the
previously performed design evaluation tests. An endurance test need not be performed
provided the vendor can demonstrate to the satisfaction of the design review agency concerned
that the pump to be offered has proved satisfactory in previous Navy shipboard service under
conditions equally as strenuous as those specified in the ordering data. The proposed design
evaluation test procedures shall be submitted to the design review agency for anproval prior
to performing the tests. The design evaluation tests shall consist of the following:
(a)
Endurance test (see 4.3.3.1).
(b)
Shock test (see 4.3.3.2).
(c)
Inclined operation test (see 4.3.3.3).
(d)
Vibration test (if specified in 6.1) (see 4.3.3.4).
#
4.3.3.1 Endurance test. The pump shall be operated for a period of not less than
500 hours of actual running time with a minimum of 100 starts to ascertain reliability of
performance and operation.
4.3.3.1.1 Prior to commencement of the endurance test and immediately after completion
of the 500 hour operating run, the pump and driver shall be disassembled to the extent neces-
sary and the critical dimensions and running clearance, of parts subject to wear, erosion
and derangement, measured, calculated and recorded. All components such as turbine rotors
and nozzles and pump impellers and casings subject to erosion, corrosion, cavitation, steam .
cutting and wear, the effects of which are not subject to routine measurement shall be
listed in the inspection record and after completion of the test the condition of each compo-
nent shall be determined and recorded.
4.3.3.1.2 During the initial and final hours of the endurance test run, capacity and
noise tests in l ccordance with 4.3.1.3 and 4.3.1.4 shall be performed to determine the
changes in the pump's performance characteristics and noise signature. Vibration measure-
ments shall be taken at the bearin saps or housings of the pump and driver at equal speeds
during the initial and final capacity test to determine the changes in mechanical operation.
#
4.3.3.1.3 The endurance test shall not be continuous but shall be interrupted by at
least three rest periods of approximately 8 hours each. A minimum of 109 starts (at full
line voltage for motor driven pumps) shall be performed during the course of the test.
During an early part of the endurance test the pump shall be operated continuously for 24
hours at a capacity as near free delivery as possible at maximum rated speed, and normal
specified temperature, submergence and suction conditions. During the latter part of the
endurance test the pump shall be operated as near shut off as possible for 12 hours contin-
uously. The remainder of the endurance test shall be run at maximum rated speed and within
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