1、 _ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising ther
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5、02-05 Stabilized 2013-06 Superseding AIR4713 Aerospace - Chlorinated Solvent Contamination of MIL-H-5606/MIL-H-83282 Vehicle Hydraulic Systems RATIONALE This document has been determined to contain basic and stable technology which is not dynamic in nature. STABILIZED NOTICE This document has been d
6、eclared “Stabilized“ by the A-6C3 Fluids Committee, and will no longer be subjected to periodic reviews for currency. Users are responsible for verifying references and continued suitability of technical requirements. Newer technology may exist. Copyright SAE International Provided by IHS under lice
7、nse with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TABLE OF CONTENTS1. SCOPE . 41.1 Purpose 42. APPLICABLE DOCUMENTS52.1 SAE Publications .52.2 Military Publications .53. FLUID SAMPLE ANALYSIS TECHNIQUES.53.1 Fluid Sample Analysis Techniques 53.2 Specific
8、Analysis Techniques 53.2.1 Gas Chromatography 53.2.2 Microcoulometric Procedure. 63.2.3 X-ray Fluorescence Spectroscopy Method. 64. SOLUBLE CHLORINE CONTAINING CONTAMINANTS.94.1 Potential Contaminant Sources . 95. RECOMMENDATIONS 105.1 Contaminant Allowable Limits105.2 Recommended Chlorine Contamina
9、tion Allowable Limits 105.3 Contamination Removal Methods. 105.3.1 Drain. Refill and Flush 105.3.2 Purification Equipment Method105.4 Recommended Maintenance Practices 11APPENDIX A . 12SAE AIR4713A Page 1 of 12_ Copyright SAE International Provided by IHS under license with SAENot for ResaleNo repro
10、duction or networking permitted without license from IHS-,-,-FOREWORDIn June 1982 a study entitled “Investigation of Air Force MIL-H-5606 Hydraulic System Malfunctions Induced by Chlorine Solvent Contamination“ (AFWAL-TR-82-4027) was issued by the Air Force Wright Aeronautical Laboratories (AFWAL/ML
11、B) and the University of Dayton Research Institute (Bibliography 1). Information in that study reported that in 1975 a large number of C-141 mishaps occurred involving stuck selector valves in landing gear and door systems throughout the Military Airlift Command (MAC). Analysis of hydraulic fluid fr
12、om a problem aircraft hydraulic system revealed the presence of the chlorinated solvent 1,1,2- trichlorotrifluoroethane and water. Auger spectroscopy surface analysis of the stuck valve and spool assembly involved revealed the presence of elements chlorine, oxygen, iron, and carbon. With this proof
13、of chlorinated solvents being the cause of stuck valves in a C-141 mishap, a fleet wide survey of aircraft hydraulic systems was performed to determine the level of chlorinated solvents and water in hydraulic systems. Simultaneously, maintenance overhaul procedures were modified to eliminate the use
14、 of chlorinated solvents as much as possible. A maximum limit was tentatively established for chlorine contamination in C-141 hydraulic systems at 200 parts per million (ppm) chlorine, based on the Navys success with a 200 ppm limit with the P-3 aircraft. Upon establishing this limit, C-141 aircraft
15、 were drained and flushed if their systems exceeded this limit. The use of chlorinated solvents was banned from use in the C-141 hydraulic systems and component overhauls. As a result of that study, a level of 200 ppm maximum allowable chlorine limit was established.a. Summary: Chlorine contaminatio
16、n of aircraft hydraulic fluids has been known to cause considerable amounts of damage to hydraulic flight control systems and their corresponding component parts. In an effort to statistically reveal the origins of, and the damages caused by chlorine contamination, a survey was presented to randomly
17、 selected aerospace corporations and government organizations by the Fluids Panel of Committee A-6. Based on the preliminary data, a problem exists with chlorine contamination in hydraulic systems. Data contained in a follow-up survey identified chlorofluorocarbon based cleaning fluids as the common
18、 chlorine containing fluid in use.The source of the chlorine containing contaminants is primarily solvents used in cleaning/degreasing of aircraft parts. Care must be exercised when such solvents are specified to minimize all opportunities for their being introduced into the hydraulic fluid. Such so
19、lvents are normally miscible with the hydraulic fluid and their presence can only be determined by laboratory analytical techniques such as those outlined in this document.b. Types and Percentages Measured: During 1975 and 1976 hydraulic fluid samples were taken from Air Force aircraft at various ba
20、ses. Aircraft sampled included C-141, B-52, F-105, F-111, F-4, T-38, C-5A, KC-135, F-106 aircraft, and crash accident samples. Also sampled were test stands, servicing carts, and new hydraulic fluids in order to study when and how the chlorinated solvents were introduced into operational hydraulic s
21、ystems. When these initial samples were taken, chlorine content was measured at the various ALC laboratories by x-ray fluorescence techniques which were later recognized to contain possible serious analytical errors. While any particular data point could be in question, the overall trends of chlorin
22、e contamination in hydraulic fluids are considered to be valid.SAE AIR4713A Page 2 of 12_ Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-c. Analysis Results: Of the 250 aircraft fluid samples analyz
23、ed, results are given in parts per million chlorine, number of samples analyzed with that value, and the percentage of the total samples. (1) 300 ppm and above: 1 sample, 1%(2) 200 - 300 ppm: 5 samples, 2%(3) 100 - 199 ppm: 38 samples, 15%(4) 0 - 100 ppm: 205 samples, 82%Of the ground equipment flui
24、d samples (703 total), 52% contained over 200 ppm chlorine. Of the new fluid samples analyzed (25 total), 8% were over 200 ppm chlorine.It can be seen from this data that ground support equipment and new fluid can be a source of contamination. These data further document that the then current levels
25、 of chlorine in hydraulic fluid systems were at a serious level, Air Force wide, as these chlorinated solvent levels were in the ranges which had caused corrosion in Navy aircraft.SAE AIR4713A Page 3 of 12_ Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproducti
26、on or networking permitted without license from IHS-,-,-1. SCOPE:Although there is controversy regarding the chemical form of chlorine and its relation to harmful effects in the hydraulic fluid (i.e., chloride ions versus organic chloro-compounds versus total chlorine in all forms), it is generally
27、agreed that total chlorine content should be measured and controlled. In the near future, the ban on the manufacture of chlorinated solvents, out of concern for depletion of the ozone layer, may in itself diminish or eliminate chlorine contamination related aircraft malfunctions. It is generally acc
28、epted that hydraulic fluid contamination should be held to a minimum under all conditions. The benefits of low contamination levels are improved performance, lower maintenance due to lower wear, corrosion and erosion, longer fluid life, longer component life, etc.Contaminants can be classified into
29、two general types: those that are insoluble and those that are soluble in the hydraulic fluid. The insoluble solid type is most common and is usually referred to as particulate matter. Its measurement and removal have been the subject of much investigation and standardization which is well documente
30、d in technical literature. The insoluble liquid type contaminant is much less common. The resulting two phase system is often observed as hazy or cloudy fluid appearance and the recommended action is to remove the contaminated hydraulic fluid from the system.Soluble type contaminants are more diffic
31、ult to detect and to determine quantitatively. They can easily escape notice, particularly when present in small amounts. Gross contamination usually results in significant changes in fluid physical properties and can be determined by such changes. Smaller amounts are difficult to detect and measure
32、 and usually require sophisticated analytical techniques - such as infrared and other spectral techniques, gas chromatography (both head space and electron capture), microcoulometry, x-ray fluorescence, etc.Generally, the presence of undesirable soluble contaminants is unknown until they have been s
33、hown to cause performance problems. Hydraulic fluid formulations contain soluble additives in base stocks giving beneficial effects on performance. The range of possible undesirable soluble contaminants can encompass innumerable materials - solids, liquids or gases.1.1 Purpose:Of all the potential s
34、oluble contaminants, this SAE Aerospace Information Report (AIR) covers only chlorine containing materials, their detection, their effects, and suggests ways to prevent their contaminating aircraft hydraulic fluids. This document will limit itself to “chlorine containing compounds” in MIL-H-5606 and
35、 MIL-H-83282 fluids. The presence and effects of other types of materials will not be discussed in this document.SAE AIR4713A Page 4 of 12_ Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2. APPLICAB
36、LE DOCUMENTS:2.1 SAE Publications:Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.AIR810 Degradation Limits of Hydrocarbon-Based Hydraulic F1uids, MIL-H-5606, MIL-H-83282, and MIL-H-46170 used in Hydraulic Test Stands2.2 Military Publications:Available from Standardization Docu
37、ments Order Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094.MIL-H-5440 Hydraulic System, Aircraft, Type I and II, Design, Installation, and Data Requirements forMIL-H-5606 Hydraulic Fluid, Petroleum Base; Aircraft, Missile and OrdnanceMIL-H-83282 Hydraulic Fluid, Fire Resistant, S
38、ynthetic Hydrocarbon Base, Aircraft3. FLUID SAMPLE ANALYSIS TECHNIQUES:3.1 Fluid Sample Analysis Techniques:Since experience has shown that low levels (under 200 ppm) of chlorine are of interest, the standard analyses for chlorine in organic compounds involving destructive decomposition followed by
39、chloride ion determination are not applicable. Therefore, other techniques have been developed. For gross contamination, standard methods for chlorine analysis can be used.Summaries of analytical methods applicable for small amounts of chlorine are given in the following paragraphs. Care must be tak
40、en in discussing contamination reported or measured to distinguish between the level of chlorine contamination as compared to the level of a specific solvent contamination.3.2 Specific Analysis Techniques:3.2.1 Gas Chromatography: Volatile contaminants can be determined by gas chromatography using t
41、hermal conductivity or electron capture as the means of detection. The sample is chromatographed on a column containing silicon oil or other suitable materials as a liquid phase to separate the components of interest. A dual column, dual detector system is required since the oven temperature is prog
42、rammed during the analysis. The chromatogram generated from the sample is compared directly with a reference chromatogram for an equal amount of hydraulic fluid. The concentration of contaminant is determined by comparing the peak area ratio of the contaminant versus a standard hydraulic fluid compo
43、nent with the same ratio for a reference sample containing a known concentration of the contaminant. Thus, a component of the fluid is used essentially as an internal standard rather than directly comparing contaminant peak areas in the sample and reference mixture since the ability to reproducibly
44、inject a sample is limited for the small amount injected (see A.3).SAE AIR4713A Page 5 of 12_ Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.2.1 (Continued):The method is reported to detect as lit
45、tle as 0.02% of chlorinated solvents such as trichloroethylene, perchlorethylene, or trichloroethane with a precision of 2% at 3% contaminant level and a 10% at a 1% contaminant level.Analyses consisting of a combination of gas chromatography and mass spectroscopy give both positive identification a
46、nd quantification of contaminants.3.2.2 Microcoulometric Procedure: Coulometric procedures for chlorine analysis are accepted for many materials. The technique is claimed to have the relative advantage of small sample size, sensitivity, and low cost (Appendix A.3).Using a standard microcoulometric t
47、echnique, liquid samples are injected into a flowing stream of gas containing about 80% oxygen and 20% argon (by volume). The gas and sample flow through a combustion tube maintained at approximately 800 C. The chlorine is converted to chloride and oxychloride which then flow into a titration cell where they react with silver ions present. The silver ions thus consumed are coulometrica
