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Shock tests (not applicable to class CO-1 pumps) |
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|  MIL-P-18547A(SHIPS)
calibrated before and after the tests or oftener, if necessary. The specified viscosities shall be maintain
within 5 percent regardless of temperatures.
4.7.2 Shock tests (not applicable to class CO-1 pumps~.-
4.7.2.1 Unless otherwise specified in the contract or order one complete pumping unit of each type, de-
sign and size shall be subjected to the high impact shock tests specified in MIL-S-901 for type A shockproof-
ness, grade A, class III equipment, except as otherwise required herein.
4.7.2.2 When the shock tests are on a medium-weight shock machine six blows shall be applied as de-
scribed in MIL-S-901, with the mounting platform in a horizontal position and the blows applied under the
approximate center of gravity of the assembled pump unit, The pump shall be tested running and at standstill
on alternate blows. In addition to the six blows required above, two additional blows shall be applied with the
pump inclined at 30 degrees from the vertical and the blows applied under the approximate center of gravity.
The pumps shall be mounted in such a way that the horizontal component of shock is transmitted across the
axis in which the equipment is weakest. The blows shall correspond to groups II and III in table I of MIL-S-
901 and the pumps shall be running during both blows. Pumps need not be running at rated speed during shock
tests.
4.7.2.3 Equipment exactly duplicating that previously shock tested as required by 4.7.2.1 and 4.7.2.2, and
accepted, under one contract or order will not have to be retested under a subsequent contract or order ex-
cept when evidence of low shock resistance develops in installed units. The bureau or agency concerned will
initiate action with the manufacturer for correction of deficiencies, and reserves the right to require addi-
tional shock tests.
4.7.2.4 Pump units shall be shock tested with drivers unless otherwise approved by the bureau or agency
concerned. Flexible-coupled pumps shock tested with one driver will not be required to be shock tested again
when supplied with a different driver of equal or lesser weight, subject to approval of the bureau or agency
concerned. Prime movers are subject to shock tests in accordance with the applicable equipment specifica-
tions, except that, if tested on the medium-weight shock machine at least 2 blows shall be with the equipment
mounted on the inclined fixture in accordance with MIL-S-901.
4.7.2.5 A pump unit shall be considered to have failed to pass the shock tests in the event of any of the
following:
(a) Breakage of any parts, including mounting bolts.
(b) Distortion or dislocation of any part, such as shaft, mounting feet and bearings.
(c) A mechanical unbalance of more than two times the amplitude of unbalance measured prior to
tests at rated speed, or more than that permitted by the specifications for the driver. The
amplitude of unbalance both before and after the shock tests, and the speed at which measured
shall be recorded in the shock test report.
4.7.2.6 Where a manufacturer is unable to conduct these tests at his own plant, he may arrange to have
them conducted at a commercial laboratory, or Government laboratory suitably equipped to conduct tests.
Where shock tests are conducted at a Government laboratory, copies of the applicable approved drawings
shall accompany the units.
4.7.2.7 Pump units which have been subjected to the high-impact shock test and have successfully passed
this test shall be reconditioned by the manufacturer as follows:
(a) Minor deformations affecting alignment shall be corrected.
(b) All bearings shall be replaced.
(c) Each part shall be carefully examined by the manufacturer and any part which he considers sub-
standard shall be replaced.
Minor deformations shall be defined as those which do not cause unqualified rejection of the design under
high-impact shock test but which are in excess of the design dimensional tolerances specified on the applica-
ble pump drawings.
4.7.3 Vibration tests (not applicable to class CO-1 pumps) .- When specified (see 6.1) one complete pump
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