MIL-HDBK-1022A
b) Provide a fine screen mesh as follows:
Mesh
Size of Opening
Pump suctions
7
0.108 inch (2.74 mm)
(Centrifugal)
Pump suctions (Rotary)
40
0.016 inch (0.40 mm)
Meter inlets (unless
40
0.016 inch (0.40 mm)
downstream of a
filter/separator in
issue facility)
c) In all cases, ensure the effective screen area is
not less than three times the cross sectional area of the
pipe.
4.7.5
Surge Suppressors. Every effort should be made to
control hydraulic surge or shock to acceptable limits by the
design of the piping system rather than by the use of surge
suppressors. Life cycle cost analysis which might lead to
smaller sized pipe with surge arrestors is discouraged. Where
this is not possible or becomes extremely impractical, a surge
suppressor(s) may be incorporated. Use the diaphragm or
bladder type equipped with a top-mounted liquid-filled
pressure gauge, isolation valve, and drain. Locate surge
suppressors as close as possible to the point of shutoff that
is expected to cause the shock. Provide a check valve at the
bottom with a weep hole in the clapper.
4.7.6
Filter/Separators. The common aviation turbine fuel
contaminants are water, solids, surfactants, micro-organisms,
and miscellaneous contaminants. Solid contaminants are
generally those which are insoluble in fuel, most common are
iron rust, scale, sand, and dirt. However, metal particles,
dust, lint from filter material and rags, gasket pieces, and
even sludge produced by bacterial action are included. The
maximum amount and size of solids that an aircraft can
tolerate vary by aircraft type and fuel system. Close
tolerance mechanisms in turbine engines can be damaged by
particles as small as 1/20th the diameter of a human hair.
Filter/separators continually remove dirt and free water from
aviation turbine fuels. Ensure that the design requires two
separate filtrations prior to the fuel reaching the aircraft.
85
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