SYSTEM TYPE
CODE LEVEL
Systems with servo or
proportional control valves
17/14 or better
High pressure-servo
controlled
15/12 or better
Hydraulic fluid power equipment is rated according
to maximum pressure. Generally low pressure is 0 to
4.1 MPa (0 to 600 psi), medium pressure to 20.7 MPa
(3000 psi), and high pressure to 34.5 MPa (5000 psi).
Results of microscopic particle count in accordance
with SAE ARP598 are reported as the number of
particles per milliliter greater than indicated
sizes as ordinates on a graph where particle size in
microns is the abscissa. Segments of the ordinate
are assigned code levels and the code level for
particle sizes greater than 15 microns is reported
as the numerator, and the code level for particle
sizes greater than 5 microns is reported as the
denominator in the pair of range numbers in the ISO
(International Organization for Standardization)
Solid Contamination Code, as identified in SAE
J1165. Higher code levels indicate higher particle
counts per millimeter. Example: 15/12 means a code
level of 15 for particles greater than 5 microns and
a code level of 12 for particles greater than 15
microns. Filter manufacturing firms can be the
source of information regarding determination of
contamination levels and analysis and have available
portable kits for more general detection of
contamination.
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Extreme care shall be taken during shop assembly to avoid inclusion of
foreign materials into the equipment. The interior of the piping shall be
cleaned with lint free cloths and flushed with oil at a minimum velocity of
4.6 m/s 15 fps which has passed through a 10 micron filter. The cleaning
procedure shall clean the system of particles so that the contamination
level is below [_____] in accordance with SAE J1165. The manufacturer
shall take three 500 milliliter samples at random locations according to
ISO 4021. Particle counting on each sample shall be performed in
accordance with SAE ARP598 by an approved independent test laboratory.
Water content of each sample shall be below 200 ppm. If any sample does
not comply with the permissible contamination limits, the system shall be
recleaned and reinspected. The piping and valves shall be sealed with
enough oil in the system to protect the metal surfaces.
2.4.2
Cylinder Tests
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NOTE: This paragraph does not apply for cylinders of
standard manufacture and design.
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Each cylinder shall be filled with the specified hydraulic fluid filtered
to 10 microns, taking care to exclude all air. Each cylinder shall then be
hydrostatically tested at [_____] kPa psi for a minimum of 4 hours. [With
SECTION 15010A
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