ISO 4021:1992 pdf download.Hydraulic fluid power - Particulate contamination analysis - Extraction of fluid samples from lines of an operating system
1 Scope
This International Standard specifies procedures for extracting fluid samples From a hydraulic fluid power system under operation.
The preferred method is to extract fluid samples from a main flowline of an operating hydraulic system 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 of an operating hydraulic system, hut this method should only be used If a suitable sampler is not fitted.
The samples taken are used for particulate contamination analysis.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of cUrrently valid lnternatio.ial Standards.
ISO 3722:1976, Hydraulic fluid power — Fluid sample containers — Qualifying and controlling cleaning methods.
ISO 5598:1985, Fluid power systems and components — Vocabulary.
3 DefinItions
For the purposes of this International Standard, the definitions given in Iso 5598 and the following definitions apply.
3.1 clean sample bottle: Sample bottle which has been thoroughly cleaned and verified in accordance with ISO 3722.
3.2 fluId sampling, line: The extraction of a sample of fluid from a turbulent section of a flow stream.
3.3 fluId sampling, reservoir: The extraction of a sample of fluid from the reservoir of an operating system.
3.4 sampler: A device whIch allows the extraction of a quantity of representative fluid from the hydraulic system. (Sec figures 1 and 2.)
3.5 turbulent flow: Fluid flow in which particle movement, anywhere in the flow, varies rapidly In velocity and direction. Flow may be turbulent when the Reynolds number (Re) is greater than 2 300 and can be assumed to be turbulent when Re 4 000. See annex A.
4 PrincIples of fluid extraction
4.1 Sampling from fluid lines
4.1.1 Extract samples from main fluid lines in a sectioii where turbulent flow conditions exist, using a sampler having the following characteristics (see example In figure 1):
a) being compatible with the fluid and the system operating pressure;
b) permitting on/off valving of sample 110w;
5.1.3 Open the sampler and fush through the valve with a sufficient quantity (normally at least 500 ml of fuid but not less than five times the total volume of the sampler), collect in a separate container and discard. Do not close the valve afer flushing.
5.1.4 Uncap the precleaned sample bottle, place the sample bottle under the emerging jet of fluid and fill the bottle to about 75 % of its total volume. Do not allow the sampler to come into contact with the sample bottle.ISO 4021 pdf download.