Contamination Control
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Technical committeeTypeAcronymISO/TR 4813CommitteePublished year2021Description
This document provides the background for ISO 11171:2020 and the use of µm(c) as the sole means of reporting particle size for APC particle count data. It also summarizes results of the international inter-laboratory study (ILS) of its reproducibility using SRM 2806d candidate material and suspensions of Reference Material (RM) 8632a. The ILS results provided the basis for certification of SRM 2806d used for primary calibration of APC. Their implications with respect to particle counting and filter testing are discussed in this document.
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Technical committeeTypeAcronymISO/TR 4808CommitteePublished year2021Description
This document describes a recommended method for the interpolation of particle concentration and filter Beta Ratio data when results are not otherwise available at the desired particle sizes. It is applicable for assessing conformance with existing fluid cleanliness and filter Beta Ratio specifications whereby the specification and actual test results are provided in different units of particle size, for example, the specification is in µm(c), but the particle counts or Beta Ratio data are in units of µm(b).
This document is also applicable when particle sizes in specifications and available data use the same units of particle size, but do not correspond to exactly the same sizes, for example, when particle counts at 20 µm(c) are specified, but data was collected at 21 µm(c). This method allows interpolation to intermediate particle sizes within the range of existing data and does not permit extrapolation to particle sizes outside the range of available data.
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Technical committeeTypeAcronymISO 4407CommitteePublished year2002Description
This International Standard specifies methods for determining the level of particulate contamination in liquids used in hydraulic systems by counting the number of particles deposited on the surface of a membrane filter using an optical microscope. It includes particle counting by two manual methods and image analysis, using either transmitted or incident lighting systems.
Particle sizes greater than or equal to 2 micrometres can be sized and counted by this method, but the resolution and accuracy of the results will depend upon the optical system used and the capabilities of the operator.
All hydraulic fluids with a wide range of contamination levels can be analysed according to this International Standard. However, the counting uncertainty at the larger particle sizes increases if the volume filtered is reduced to allow smaller sized particles to be counted, where a fine precipitate or a high particle concentration is present.
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Technical committeeTypeAcronymISO 4406CommitteePublished year2021Description
This document specifies the code to be used in defining the quantity of solid particles in the fluid used in a given hydraulic fluid power system.
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Technical committeeTypeAcronymISO 4405CommitteePublished year1991DescriptionTechnology
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Technical committeeTypeAcronymISO 4021CommitteePublished year1992Description
The preferred method is to extract fluid samples from a main flowline in such a manner that the particulate contaminant in the sample is representative of the fluid flowing at the point of sampling. An alternative method is to extract a sample from the reservoir, but this method should only be used if a suitable sampler is not fitted.
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Technical committeeTypeAcronymISO 3968CommitteePublished year2017Description
ISO 3668:2017 specifies a procedure for evaluating differential pressure versus flow characteristics of hydraulic filters and constitutes a basis for agreement between the filter manufacturer and user.
It also specifies a method for measurement of the differential pressure generated at different flow rates and viscosities by the relevant parts of a filter assembly, spin-on and any valves contained within the filter which are in the flow stream. The typical types of filter to be tested are as follows:
Type 1: which are spin-on filters in which the replaceable unit does not include a filter head (it might or might not include the element by-pass valve);
Type 2: which are spin-on filters in which the replaceable element is tested together with a filter head (it might or might not include the element by-pass valve);
Type 3: which are filter assembly, usually of the replacement element type, that is the housing (head and bowl) and element.
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Technical committeeTypeAcronymISO 3724CommitteePublished year2007Description
ISO 3724:2007 specifies a method for determining the resistance of a hydraulic filter element to flow fatigue after it has been loaded with particulate contaminant and subjected to a uniform varying flow rate and predetermined terminal differential pressure.
It establishes a uniform method for verifying the ability of a filter element to withstand the flexing caused by cyclic differential pressures induced by a variable flow rate.
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Technical committeeTypeAcronymISO 3723CommitteePublished year2015Description
ISO 3723:2015 specifies a method for verifying the end load rating of a hydraulic fluid power filter element. It also verifies the ability of a hydraulic fluid power filter element to withstand the designated axial loading imposed by installation and use.
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Technical committeeTypeAcronymISO 3722CommitteePublished year1976Description
Specifies a method, and establishes a means for ensuring that the accuracy of particulate contamination analyses in hydraulic systems is not degraded by a lack of sample container cleanliness. Gives definitions and tabulates the inspection ratios together with the AQQL values of concern.
Technology