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Hydraulic and lubricant fluids
»Specification »Contamination
· Viscosity tests at various temperatures;
· viscosity index;
· density;
· water content;
· ashes;
· flesh point;
· yield value;
· turbidity point;
· contaminating and wear metals;
· TAN-TBN;
· Other tests.
Chemical analysis of wear metals
The chemical analysis can be carried out on wear metals in a lubricating oil, in order to make hypotheses and expectations on the residual life of the mechanical component. The obtained data can be particularly significant when the analyses are carried out on more samples taken at set times. The analysis is carried out using the simultaneous ICP spectrometer..
Why the contamination has to be controlled
The contamination control is fundamental to maintain the wholeness of all the system components: without this control the system will hardly be able to reach the expected service life limits; indeed, a contaminated fluid is to be deemed as an “abrasive fluid” that can cause several faults, also depending on the contaminating particle size.
The contaminators result in unpleasant influences that can destroy the wholeness of a system causing an unbalance among the various component tolerances.
Depending on the system intensity of exposure to contamination effects, unpleasant effects can occur such as: dirty, sedimentation, oxidation, deterioration, strains, chemical attack, corrosion, seizure, failure, abrasion, etc.
As a general rule, the most of the contaminator (70-80%) is made up of fine 5 - 15 µm particles. The action of such particles on circuit components can result in a tolerance increase, a drainage increase, a volumetric performance decrease, a temperature increase and a viscosity decrease. These effects can take very different times to occur, from a few hours to some hundreds hours.
If the polluting particles are coarse, bigger than 15 µm, the effects can be more dramatic causing an immediate seizure and system stop.
The contamination by ultra-fine particles (micropollution) causes harmful effects in valve most delicate points, e.g. obstruction of tiny calibrated holes, early wear, etc.
Contamination determination and classification
It determines the particle size and number. According to these data, the sample contamination is classified according to standards: ISO 4406 and NAS 1638.
Gravimetric determination
The contaminator dry weight is measured per unit of fluid weight or per unit of washed area. The contamination degree is given in terms of milligrams of contaminator in a litre of fluid.
Contaminator specification
The contaminator can be chemically and microscopically analysed , if necessary by means of the scanning electron microscopy with energy dispersion sound analysis, in order to understand its composition, morphology and possible origin.
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