NF ISO 4407
Hydraulic fluid power - Fluid contamination - Determination of particulate contamination by the counting method using an optical microscope
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.
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.
La présente norme fait partie d'un ensemble de normes françaises destinées à mesurer la pollution des fluides utilisés dans les transmissions hydrauliques. La méthode de comptage au microscope est importante car, bien que relativement longue et coûteuse, elle représente "la méthode de référence" permettant de juger les autres méthodes.
- Avant-proposiv
- Introductionv
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1 Domaine d'application1
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2 Références normatives1
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3 Termes et définitions2
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4 Principe de comptage4
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5 Appareillage4
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6 Réactif et produits chimiques6
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6.1 Réactif et produits chimiques de rinçage et de nettoyage6
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6.2 Liquides de transparisation de la membrane filtrante (méthode en lumière transmise)6
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7 Mode opératoire de nettoyage de la verrerie7
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8 Méthodes d'étalonnage7
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8.1 Étalonnage du microscope7
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8.2 Détermination de la surface utile de filtration (SUF)7
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9 Préparation de la membrane filtrante8
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9.1 Préparation de l'échantillon8
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9.2 Analyse à blanc8
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9.3 Séparation des polluants par filtration sous vide9
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9.4 Évaluation de l'aptitude au comptage10
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9.5 Montage des membranes pour observation en lumière transmise10
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10 Classification des particules et méthode de comptage11
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10.1 Classification des particules11
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10.2 Choix du grossissement nominal11
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10.3 Méthode de comptage statistique11
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10.4 Calcul du nombre total12
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10.5 Vérification des résultats13
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11 Expression des résultats14
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12 Phrase d'identification (Référence à la présente Norme internationale)14
- Bibliographie15
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