Did you know that mechanical contaminants in oil are the most destructive factor affecting the service life of equipment? When considering the causes of wear and tear on lubricated components in equipment, as much as 82% of these processes are related to the presence of mechanical contaminants in the oil.
Did you know that mechanical contaminants in oil are the most destructive factor affecting the service life of equipment? When considering the causes of wear and tear on lubricated components in equipment, as much as 82% of these processes are related to the presence of mechanical contaminants in the oil.
A deterioration in oil cleanliness by one class means a doubling of the amount of contaminants in the sample for a given interval. The level of contamination should be within the requirements specified by the equipment manufacturers. It should also be remembered that the higher the pressure, speed and lower the technological clearances, the better the cleanliness class should be.
It is estimated that improving oil cleanliness by just one grade should result in an increase in trouble-free operating time, as shown below:
Conversely, a deterioration in cleanliness class reduces service life!
The result of the cleanliness class test is presented as a numerical code depending on the standard used. The most commonly used standards (technical norms) defining the cleanliness class of oil are: ISO 4406, NAS 1638, SAE AS 4059.
The NAS 1638 coding system was developed in 1964 to define the contamination class for fluids used in aircraft. Due to the lack of alternatives at the time, the use of this standard was also extended to industrial hydraulic systems.
The coding system specifies the maximum permissible particle counts in 100 ml of volume in different size ranges (differential counting). Although the standard does not provide guidance on how to present the result, a single code is generally given – it corresponds to the highest level recorded for all particle size ranges.
The coding system developed by the International Standards Organisation (ISO) according to ISO 4406:1999 is currently the most preferred method of classifying contamination. The numerical code for individual contamination levels consists of three numbers that enable the size and distribution of particles to be determined as follows:
For automatic particle counters: 18/16/13
For microscopic examination: -/16/13
18/16/13
-/16/13
The SAE AS 4059 standard is an extension of the NAS 1638 standard and defines the level of cleanliness using an alphanumeric code. Particle size ranges are designated by letters from A to F, and particle quantity ranges from 000 to 12.
In practice, results are given for all intervals, using cumulative or differential counting.
The required cleanliness classes may be more stringent depending on the specific nature of the system and the manufacturer’s requirements.
ISO 4406:1999 21/20/17
NAS 1638 11
SAE AS4059 12A/11B/11C
ISO 4406:1999 14/12/9 NAS 1638 3 SAE AS4059 4A/3B/3C
The method of classifying oil purity is one aspect, but another important element is the testing method, as not every method can be used for every type of oil.
Filtering 100 ml of oil through a membrane with a porosity of 1.2 µm (ISO 4407) with microscopic evaluation can be performed manually – by an experienced laboratory technician – or automatically, using a microscope with appropriate software. This is a classic method for which there are virtually no interferences.
In addition to determining the cleanliness class, it provides a realistic interpretation of the origin of particles in oil, e.g. wear metals, seal materials or dust from the environment. The method is recommended for all types of oils, except for PAG-based synthetic oils.
For the automatic method, particles can be classified according to ISO 4406, NAS 1638, SAE AS 4059 and many others. For the manual method, the ISO 4406 classification is most commonly used.
This method is also implemented by Ecol’s specialised service teams on site at the customer’s premises, e.g. during oil filtration services.
An automatic dilution method which, through the use of dilution techniques, eliminates interference associated with the presence of water and soluble sediments. The device allows for the testing of all types of oils – mineral, synthetic, phosphate esters, as well as cloudy and very dark oils (e.g., motor oils).
Particles can be classified according to ISO 4406, NAS 1638, SAE AS 4059, and many other standards.
Testing with an optical laser particle counter with optical particle analysis (PSC – Particle Shape Classification, Laser Net Fines)
Due to the limitations of the device, this method cannot be used for phosphate esters, heavily contaminated, dark, and cloudy oils.
Particle classification is possible according to ISO 4406, NAS 1638, SAE AS 4059, and many other standards.
Cleanliness testing with an automatic block particle counter
The measurement principle is based on the pressure difference that occurs when the pores of the filter channels of individual membranes are blocked. With reference to the reference measurement, the cleanliness class can be determined without actually counting the particles.
The method is characterized by low interference and can be used for all types of fluids, including water-based ones. However, it requires a larger sample size, which is why it is most often used during on-site service visits.
Maintaining oil cleanliness at an optimal level is undoubtedly one of the measures to reduce equipment failure rates, extend their service life, and improve availability. The key to maintaining the appropriate cleanliness level is regular cleanliness testing performed using appropriate methods.
The timing of the tests is also important. At the Ecol laboratory, depending on the needs, results can be delivered on an express basis – even within a few hours of receiving the sample.
please contact us:
Nie udało się nawiązać połączenia z siecią. Upewnij się, że masz dostęp do internetu, a następnie odśwież stronę, aby kontynuować korzystanie z serwisu.
