MIL-PRF-2940D
4.6.4.1 Vibration fixture. The snubber shall be connected to the
outlet side of an instrument cutoff valve. The valve and snubber assembly
shall be mounted to a vertical panel of the vibration fixture using the valve
mounting nut and lockwasher. A flexible hose shall be used to connect the
pressure source to the inlet side of the instrument cutoff valve. A flexible
hose shall be used to connect a pressure monitor (gauge or transducer) to the
test connection port located in the stem of the instrument cutoff valve.
Flexible pressure hoses shall be of sufficient length so as not to interfere
with the vibration fixture and shall have appropriate pressure ratings. The
snubber shall be mounted to the instrument cutoff valve as indicated below for
the various snubber end connection types. After filling and pressurizing the
system, the snubber and pressure monitor shall be isolated from the pressure
source by means of the instrument cutoff valve.
4.6.4.1.1 O-ring union connection. Thread the output side of the
snubber onto the output side of the instrument cutoff valve. Seal the inlet
side of the snubber with a blanked tailpiece after the system is filled.
4.6.4.1.2 Flareless (bite type) connection. Mount the outlet side of
the snubber to the outlet side of the instrument cutoff valve by means of an
O-ring union to flareless (bite type) adapter in accordance with Drawing
803-1385850. Seal the inlet side of the snubber after the system is filled.
4.6.4.1.3 Pressure transducer connection. Mount the inlet side of the
snubber to the outlet side of the instrument cutoff valve by means of a short
length of 1/4-inch od stainless steel tubing and fittings in accordance with
MIL-F-18866. As required, clamp the snubber to the vibration fixture to
prevent movement during test. Seal the outlet side of the snubber after the
system is filled.
4.6.5 Shock. A lightweight shock test shall be conducted in accordance
with MIL-S-901 for grade A, class 1, type A equipment. A total of nine blows
shall be applied, three blows applied parallel to each axis of the snubber.
The snubber shall be pressurized to 250 + 10 psi for a class L snubber and
1500 + 50 psi for a class H snubber and monitored throughout the test. The
snubber shall meet the requirements of 3.4.5.
4.6.5.1 Shock fixture. The snubber shall be connected to the outlet
side of an instrument cutoff valve. The valve and snubber assembly shall be
mounted to a vertical panel of a type 6D-1 adapter plate using the valve
mounting nut and lockwasher. A flexible hose shall be used to connect the
pressure source to the inlet side of the instrument cutoff valve. A flexible
hose shall be used to connect a pressure monitor (gauge or transducer) to the
test connection port located in the stem of the instrument cutoff valve.
Flexible pressure hoses shall be of sufficient length so as not to interfere
with the shock fixture and shall have appropriate pressure ratings. The
snubber shall be mounted to the instrument cutoff valve as required for the
various snubber end connection types (see 4.4.1.1 through 4.4.1.3). After
filling and pressurizing the system, the snubber and pressure monitor shall be
isolated from the pressure source by means of the instrument cutoff valve.
4 6.6 Pressure integrity. Pressurize the snubber to a value indicated
in table VI appropriate to the snubber class. Isolate the pressurized snubber
from the pressure source and monitor the snubber pressure with the appropriate
range pressure transducer or pressure gauge. Maintain the pressure for a
period of 1 hour. The snubber shall meet the requirements of 3.4.6.
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