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Page Title:
Flow rate and filtering ability test. |
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|  MIL-F-20627B
fuel circulated through the system for a period of
4.5 Examination and tests. -
8 hours at rated flow for the element being tested
and with the fuel held at a temperature of 100
4.5.1 Type 1, filter assembly. -
This 8-hour circulation period shall be re-
peated on additional test elements until a total of
4.5.1.1 Examination.- Type 1 filter assemblies
four have been flowed in the same manner without
selected in accordance with 4.4.1.2 shall be exam-
a change or addition to fuel in the reservoir. Each
ined to determine conformance to all Of the require-
element removed from the filter assembly shall be
ments of this specification not involving tests.
allowed to drain back into the filter assembly for a
period of 5 minutes prior to starting a subsequent
4.5.1.2 Hydrostatic pressure test. - Filter as-
run. At the completion of the fourth 8-hour circula -
semblies selected in accordance with 4.4.1.2 shall
tion period. the strainer and strainer assembly
be subjected to a hydrostatic test pressure of 150
shall be cleaned as specified for the 4-hour circula-
p.s.i.
tion periods (without element) (see 4.5.3.1) and the
amount of foreign matter determined to the nearest
4.5.2 T y p e II, filter elements. -
0.5 milligram. The total weight of foreign matter
collected shall be divided by four and the value re-
4.5.2.1 Examination. - Type II, filter elements
ported as media migration.
selected in accor dance with 4.4.2 shall be examined
to determine conformance to the design, dimensions
4.5.4 Flow rate and filtering ability test. -
and details of construction and any other require-
ments specified herein not involving tests.
4.5.4.1 A p p a ratus. - A test apparatus shall be
constructed in accordance with figure 4. It shall
4.5.3 Media migration test. - Filter elements
include suitable machinery, controls and instru-
shall be tested for media migration in a system
ments to:
consisting of a reservoir, a pump, a standard fuel
filter body, a metal edge strainer (Purolator type
(a) Permit regulation of flow through the fil-
D-21 WM-20 with 0.0015 inch spacing or equal,
ter between 25 and 200 g.p.h.
with fabric element removed), a flow meter and a
(b) Maintain a constant flow of 50 g.p.h. at
return line to the reservoir. The components shall
25 p.s.i. head.
be connected in series as enumerated above and
Control the fuel oil temperatures between
shall be so connected as to minimize sharp corners
(c)
and
and crevices where solids would be likely to build
(d) Add water at the rate of 0.25 g.p.h.
up. One and one-half to 5 gallons of Diesel fuel test
(e) Add solid contaminant at the rate of 50
oil shall be circulated through the metal edge strainer
grams per hour.
for a 4-hour period at rated flow for the element
Take inlet and effluent samples.
to be tested and with the fuel held at a temperature
(f)
At the end of this 4-hour period,
(g) Measure pressure differential across the
of 100
the strainer shall be removed and placed over a
element(s).
Prevent recirculation of water and solids.
clean glass beaker to collect the fuel drainage. The
(h)
strainer shall be rinsed into the. beaker with ASTM
precipitant ion naphtha which has been filtered through
The filter case shall be modified as shown on fig-
a Gooch crucible (Selas No. 28-080XF or equal,
ure 4 to permit measurement of pressure drop
fritted or sintered integral bottom) using a rubber
across the element(s) only. The capacity of the
reservoir shall be such as to permit continued cir-
policeman to clean all strainer surfaces. All fuel
remaining in the strainer assembly shall be drained,
culation of the fuel oil after withdrawal of samples
the strainer assembly shall be rinsed with filtered
having a total volume of 6 gallons.
naphtha and both the fuel and the washings shall be
4.5.4.2 Contaminant feed. - The solids con-
collected in the same beaker used for the washings
taminant shall be a fine grade standardized air
from the strainer. The fuel and washings shall be
filtered through a tared Gooch crucible (Selas No.
cleaner test dust. It shall be added as a dry pow-
28-080XF or equal). The crucible shall be washed
der, at an essentially constant rate, to a funnel
with filtered naphtha, dried in an oven at 212 F.,
which is flushed with clean fuel. This mixture shall
be rejected into the fuel system near the filter inlet
cooled in a desiccator and weighed.
by a suitable pump. Filtered tap water, when used
4.5.3.1 The 4-hour circulation (without element)
as a contaminant, shall be added to the funnel and
shall be repeated until a run shows a removal of
rejected with the solids-fuel mixture.
foreign matter from the fuel not to exceed 1.0 mil-
4.5.4.3 Analysis of samples. - Samples shall
ligram.
be analyzed for soli ds content as follows:
4.5.3.2 A sample fuel filter element shall be
(a) Materials. -
Installed in the standard filter assembly and the test
(1) Crucibles, procelain perforated
bottom Coors size 4 or equal.
5
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