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Page Title:
Mechanical soundness and capacity test |
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|  MIL-P-17881D (SHIPS)
(c)
Mechanical soundness and capacity test (see 4.3,1.3).
(d)
Noise test (to be performed only when specified (see 4.3.1.4 and 6.1).
(e)
Radiographic examination (see 4.3.1.5).
(f)
Thrust test (if specified in 6.1) (see 4.3.2.3).
Each pump casing shall be tested hydrostatically to
imes maximum discharge pressure. The hydrostatic test pressure
shall be maintained for at least 30 minutes or longer as necessary for examination of entire
casing.
The pump shall exhibit no leakage through the casing material or
Acceptance criteria:
joints.
4.3.1.2 Over speed test. Each pump driven by a variable speed driver capable of over-
speeding shall be operated continuously for 30 minuets at a speed 25 percent above maximum
design operating speed. The pump need not be under load except as necessary to prevent
damage or injury. Continuous shaft and rigid coupled pumps shall be tested with the driver.
Units separately driven through flexible couplings and geared units may be tested by separate
pump, gear unit and driver over speed tests. For pumps not requiring a noise test, the
over speed test may be conducted on each pump rotating assembly in any casing of the design
supplied on the contract or order. The dynamic balance shall be checked by the use of a
vibration indicator of a type whereby vibration of an amplitude of 0.001 inch may be readily
observed on a scale.
Acceptance criteria: Neither the pump nor the driver shall exhibit noises or roughness
#
of operation. The maximum acceptable readings of the vibration indicator shall not exceed
the limits shown in MIL-STD-167 for this equipment.
4.3.1,3 Mechanical soundness and capacity test. This shop test shall be conducted,
recorded and reported
ugal pump Rating Standard and Test Code
of the Hydraulic Institute, to the extent that these standards are applicable and are not
in conflict with the requirements specified herein. The test record for each pump shall
identify the pump by manufacturers' serial number. It shall indicate the diameter of the
pump impeller(s) being tested in the pump, it shall include a description (by legend and
sketch) of the test stand arrangement including an identifying list of test instruments used
and the date when last calibrated, and it shall include the data sheets of all recorded data
and sample calculations of data conversion to specified conditions. Test data used for
plotting the head-capacity curve shall be corrected to the specified operating conditions.
The test shall be performed in three phases, as follows:
(a) Operate the pump and its driver if motor driven, continuously at maximum
rated speed and capacity, with the pumped fluid within plus or minus 20F.
of the specified operating temperature (see 6.1) until bearing temperatures
(not including water-lubricated bearings) stabilize as manifested by at
least three consecutive equal bearing temperature indications taken at
intervals of not less than 15 minutes. The pump operation shall be fully
monitored throughout this test for proper functioning of packings and seals
and bearing lubrication, and for smooth running. The amount of packing
leakage shall be measured at regular intervals and recorded. Rolling contact
bearing temperature shall meet the requirements of 3.3.9.4.
Acceptance criteria: Operation shall be without
over heating and shall be free of
abnormal vibrations and noises. Oil temperature rise
in force-feed lubricated bearings shall
not exceed 50F. in any bearing and shall not exceed
a maximum temperature of
with
inlet cooling water to the oil cooler at 85F. There
shall be no abnormal leakage of water
or oil.
(b) Operate the pump at the maximum rated speed, from recirculation flow to as
close to free delivery as practicable and with the specified suction con-
ditions prevailing. The unit shall be operated at 7 or more test points,
throughout the full operating range, to establish accurately the head-
capacity curve at maximum rated speed. The unit shall be operated at each
test point until the test values being measured stabilize.
Acceptance criteria: The pump shall deliver the rated capacity and head. The head-
capacity curve at maximum rated speed shall satisfy the specified requirements. The total
head at all capacities on the curve other than rated capacity shall not deviate by more than
plus 5 percent os minus 2 percent of rated heads under 500 feet, plus 3 percent or minus 1
percent of rated heads over 500 feet from the corresponding head on the head-capacity curve
at maximum rated speed established in the performance test specified in 4.3.2.1. Bearing
temperatures shall have remained normal and within the limits specified.
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