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|  MIL-C-18419B(SHIPS)
finish of the run and at regular intervals, not ex-
(c) Volumetric efficiency.
ceeding 1/2 hour throughout the run.
(d) overall efficiency of compressor that is,
compression efficiency versus mechan-
4. 5. 3.4 Recorded data. -
ical efficiency. Theoretical air horse-
power upon which efficiency is based may
(a) Mechanical:
be calculated from either the adiabatic or
(1) Ambient shop conditions:
isothermal base, but test data should
a. Dry bulb ambient temperature.
indicate which is used.
b. Wet bulb ambient temperature,
c. Intake temperature (in air stream
4.5.3.4.2 During each operation test the function-
close to intake).
ing of the electrical and mechanical equipment shall
d, Barometer readings. ,
be smooth and free from excessive heating, noise,
(2) Air discharge pressure from each
and vibration and the performance m all respects
stage of compression.
shall meet the requirements of this specification.
(3) Final air temperature at discharge
from aftercooler.
4.5.3.5 Noise tests.- During the latter part of
(4) Air temperatures before and after
each performance test of compressors required to be
each stage of compression,
sound isolated, airborne and structure borne noise
(5) Circulating water relet and outlet
tests shall be conducted. Testing and reporting shall
temperatures.
be m accordance with MIL-STD-740. Details of
(6) Quantity of cooling water in gallons
compressor noise test stand, instrumentation and
per minute.
test measurements shall be as mutually agreed upon
(7) Revolutions per minute of driving unit
between the compressor manufacturer and the Bureau
and of compressor.
of Ships.
(8) Temperature of lube oil in crankcase.
(9) Time required to fill flask of meas-
4.5.3.5.1 During the preproduction tests (see
ured volume.
4. 4) a series of four noise tests, shall be conducted
(b) Electrical:
as follows:
(1) Volts, amperes and frequency.
(2) Power input to motor.
(a) During the latter part of the initial 8-hour
(c) Operational
performance test (see 4.5.3. 3).
(1) Operation of the automatic temperature
(b) During the final hours of the 300-hour test
control.
(see 4.4.202).
(2) Operation of the automatic unloading
(c) During the first four hours of the last 200-
devices,
hours test (see 4.4.2.3).
(3) Operation of the automatic moisture
(d) During the final hours of the 200-hours test.
separator drainage system.
(4) Operation of moisture separators.
4.5.3.6 Upon completion of the performance tests,
(Include record of quantity of oil and
each compressor and its access ories shall be disas-
water drained manually at 15-minute
sembled sufficiently to permit inspection of all parts
intervals from each separator for a
subject to wear or damage by running, these parts to
period of 2 hours during preproduc-
include bearings, wrist pins, pistons and piston rings,
tion tests).
cylinders, and air valves. To be acceptable no parts
(5) Operation of lube oil heater and
of the compressors shall show any signs of failure or
thermostat.
excessive wear, The condition of the compressors at
(6) Total amount of cylinder lube oil used
the conclusion of all tests shall be noted on the of ficial
during test period,
test sheets.
4.5.3.4.1 Computed and recorded data, - The
4.5.317 Each compressor unit not selected in
following data shall be computed from the recorded
accordance with table XII shall be subjected to tests,
data and shall be included on each test data record:
exactly as required by 4.5, 3.3 and 4.5, 3.5 except:
(a) Capacity in cubic feet of air per hour
(a) The duration of the running test need nor
actually delivered at rated discharge
exceed 4 hours, and data is required to
pressure.
be taken only at the start and finish of the
(b) Brake horsepower at the compressor
run and once in between;
shaft (computed from previous test of `
(b) The units need not be disassembled upon
motor).
completion of the performance tests,
20
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