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Standard

Methods for Evaluating Cryogenic Filters

2019-12-03
CURRENT
ARP900C
The purpose of this document is to present test methods that can be utilized to evaluate the filtration and operating characteristics of filters that will be utilized in a cryogenic system. The methods presented herein are intended to supplement standard filter testing specifications to allow evaluation of filter performance characteristics in areas that could be affected by extreme low temperatures.
Standard

Filter Element Cleaning Methods

2019-07-15
WIP
AIR787B
This SAE Aerospace Information Report (AIR) provides technical information to assist the development of specific cleaning methods for filter elements. Consideration is limited to filter elements which are designated as "cleanable" (not "disposable"), but which cannot be cleaned by simple and obvious procedures. Cleaning methods developed according to this report should be evaluated by the methods of ARP725. Satisfactory cleaning methods can be developed for most "cleanable" filter elements. Technical or economic feasibility of the cleaning method may be limited, however, by incompatibility of filter-element construction materials, by mechanical weakness or lack of corrosion resistance to withstand repeated or continued cleaning, or by the presence of unusually tenacious contamination. These factors must be considered when selecting approaches to the development of specific methods.
Standard

Methods, Locations and Criteria for System Sampling and Measuring the Solid Particle Contamination of Hydraulic Fluids

2019-07-15
WIP
ARP5376C
This SAE Aerospace Recommended Practice (ARP) provides procedures for assuring cleanliness of sampling equipment, for performing the sampling process, and for measuring and reporting the sample particle count. The ARP specifies procedures for cleaning sample bottles, when used, and recommends the solvents to be applied and how these solvents should be prepared. Requirements for the selection of the sampling point, sampling method, and sampling frequency are also specified. This ARP also specifies three measuring methods for determining the level of solid particle contamination of hydraulic fluids used in aerospace hydraulics. These are: a. on-line automatic particle counting; b. automatic particle counting method using bottle samples; c. microscopic particle count method using bottle samples.
Standard

Aerospace - Evaluation of Particulate Contamination in Hydraulic Fluid - Membrane Procedure

2018-08-13
CURRENT
ARP4285A
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.
Standard

Bubble-Point Test Method

2017-04-04
CURRENT
ARP901B
This test method describes a procedure for measuring the largest pore or hole in a filter or similar fluid-permeable porous structure. A standard referee test method for precise determination or resolution of disputes is specified. A simpler inspection test procedure for quality assurance “go-no-go” measurement is also given. Bubble-point testing physics, analysis of bubble-point test data, and correlation with other methods of pore size determination are separately discussed in the appendix.
Standard

Evaluating Effectiveness of Filter Element Cleaning Methods

2014-06-03
CURRENT
ARP725B
This SAE Aerospace Recommended Practice (ARP) presents a procedure for evaluating cleaning methods with respect to contaminant removal and element degradation particularly for metallic filter elements. A procedure for checking durability of cleaning equipment and a referee cleaning method are also included. It is applicable only to the evaluation of cleaning methods proposed for removal of service dirt and not for built-in dirt, liquid oxygen (LOX) cleaning, etc. Supporting information for use with the ARP is also included.
Standard

Aerospace Fluid Power - Contamination Classification for Hydraulic Fluids

2013-09-27
CURRENT
AS4059F
This SAE Aerospace Standard (AS) defines contamination classes and levels for particulate contamination of hydraulic fluids and includes methods of reporting related data (Appendix A). The contamination levels selected are based on the widely accepted NAS 1638 cleanliness classes. The conversion from NAS 1638 cleanliness class specifications to AS4059 class specifications is defined. The comparison of the NAS 1638 classes to AS4059 classes and levels is provided and are defined and the differences explained (Appendix B). NAS 1638 classes based on weight of particles are not applicable to these classes and are not included. A contamination code has been added to describe the contamination levels of the fluid at the specified particle size ranges.
Standard

Aerospace-Particle Count Data Conversion and Extrapolation

2012-09-24
CURRENT
AIR877C
This SAE Aerospace Information Report (AIR) describes a mathematical model that can be used to analyze particle count data. Particle counts that fit the model can be graphically displayed, converted from one counting size-frequency range to another, and extrapolated to estimate counts beyond the measured range. Derivation, applications, and calculations are described.
Standard

Aerospace Microscopic Sizing and Counting of Particulate Contamination for Fluid Power Systems

2012-01-19
HISTORICAL
AS598
This SAE Aerospace Standard (AS) defines the materials, apparatus and procedure for sizing and counting of particulate contamination, 5 µm or greater, in hydraulic fluid samples by membrane filtration with microscopic counting. The microscopic counting method is capable of counting particulate matter in samples withdrawn from fluid power systems as identified by the 12 classes of AS4059 and projected beyond these for the five standard ranges specified and can thus serve as the primary document to determine acceptability. It is also capable of revealing but not measuring evidence of abnormal amount of water, other fluids, fine particulate and other materials, especially fibers and metals. It is applicable to all military, civil, space vehicles and test equipment.
Standard

Methods, Locations And Criteria For System Sampling And Measuring The Solid Particle Contamination Of Hydraulic Fluids

2010-03-08
CURRENT
ARP5376B
This SAE Aerospace Recommended Practice (ARP) provides procedures for assuring cleanliness of sampling equipment, for performing the sampling process, and for measuring and reporting the sample particle count. The ARP gives procedures for cleaning sample bottles, when used, and recommends the solvents to be applied and how these solvents should be prepared. Requirements for the selection of the sampling point, sampling method, and sampling frequency are also specified. This ARP also recommends three measuring methods for determining the level of solid particle contamination of hydraulic fluids used in aerospace hydraulics. These are: a on-line automatic particle counting; b automatic particle counting method using bottle samples; c microscopic particle count method using bottle samples.
Standard

Aerospace - Dynamic Test Method for Determining the Relative Degree of Cleanliness of the Downstream Side of Filter Elements

2008-06-22
CURRENT
ARP599D
This SAE Aerospace Recommended Practice (ARP) describes a procedure for determining the insoluble contamination level of the downstream side of filter elements. Results of this procedure represent the particulate released from the tested filter element under the prevailing conditions of the test. The results may be used for comparative evaluation of the effectiveness of various cleaning methods or the cleanliness of elements after cleaning or as received from manufacturers.
Standard

Liquid Filter Ratings, Parameters and Tests

2008-06-04
CURRENT
AIR887C
This SAE Aerospace Information Report (AIR) identifies and explains the meaning of various ratings and terms used to describe the physical characteristics of liquid filter elements. The significance of various filter parameters is discussed. In addition, a number of filter test methods are briefly described. This AIR and the data presented are only applicable where the system liquid wets the filter elements.
Standard

Aerospace Fluid Power - Cleanliness Classification for Hydraulic Fluids

2005-05-02
HISTORICAL
AS4059E
This SAE Aerospace Standard (AS) defines cleanliness classes for particulate contamination of hydraulic fluids and includes methods of reporting related data (Appendix A). The contamination classes selected are based on the widely accepted NAS 1638 cleanliness classes. Conversion from NAS 1638 cleanliness class specifications to AS4059 class specifications is defined. Comparison of the NAS 1638 classes to AS4059 classes is defined and the differences explained (Appendix B). This document provides versatility in identifying a maximum class in multiple size ranges, total number of particles larger than a specific size or designating a class for each size. NAS 1638 classes based on weight of particles are not applicable to either of these classes and are not included.
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