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This document reviews briefly the subject of woven metal screens. Conditions that can promote damaging corrosion in stainless steel filter screens are discussed and recommendations are listed for minimizing corrosion damage. This is a general document only; for specific applications it is suggested that the reader refer to the technical literature, and selected references listed below.

This document reviews briefly the subject of woven metal screens. Conditions that can promote damaging corrosion in stainless steel filter screens are discussed and recommendations are listed for minimizing corrosion damage. This is a general document only; for specific applications it is suggested that the reader refer to the technical literature, and selected references listed below.

This SAE Aerospace Recommended Practice (ARP) describes two procedures for sampling particles in dust controlled spaces. One procedure covers airborne dust above 5 μm. The other (and newly added procedure) covers particles of 25 μm and larger that “fall out” of the environment onto surfaces. In each case the particles are sized in the longest dimension and counted. Airborne particles are reported as particles per cubic meter (cubic foot) whereas particles collected in fall out samples are reported as particles per 0.1 square meter (square foot). This document includes English units in parentheses as referenced information to the SI units where meaningful. These procedures may also be used for environmental analysis where the quality of the particles by visual or chemical analysis is intended.

This method describes the procedure for (1) sampling air in contamination controlled spaces for air-borne particulate contamination 5μ or greater in size and for (2) the microscopic determination of the concentration and size range distribution of the particulate material removed from the air sample (Note 1).

This SAE Aerospace Recommended Practice (ARP) establishes a method for evaluating the particulate matter extracted from the working fluid of a hydraulic system or component using a membrane. The amount of particulate matter deposited on the membrane due to filtering a given quantity of fluid is visually compared against a standard membrane in order to provide an indication of the cleanliness level of the fluid. A particular feature of this method is the membrane preparation to achieve an even particulate distribution on the membrane suitable for other applications. Membrane evaluation using standard membranes, described in this document, is an alternative technique to counting with either an optical microscope (ARP598) or an automatic particle counter (ISO 11500). The latter particle counting procedures are considered more precise.

This document discusses the relative merits of the physical and chemical properties of hydraulic fluids in relation to the aerospace hydraulic system design, and the related materials compatibility. The discussion in this report applies both to hydrocarbon and phosphate ester based aircraft hydraulic fluids. In some cases, numerical limits are suggested, but, in general, the significance and effect of a property is noted qualitatively.