ISO HYDRAULIC FLUID POWER – FILTERS – MULTI-PASS METHOD FOR EVALUATINGFILTRATION PERFORMANCE OF A FILTER ELEMENT. Introduction. The obsolescence of AC Fine test dust (ACFTD) has led to the adoption of a new test dust, ISO Medium Test. Dust (ISO MTD), and the impending. ISO Multi-Pass Test. The multi-pass test is a means of determining a filter’s performance; it measures the ability of the filter to remove particles of test dust.
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However, the multi-pass test is carried out in a laboratory under steady-state conditions and does not represent strenuous operational conditions.
Strategies to Protect Grease Fittings from Contaminants. This article will focus on the impact the new standards have on selecting candidate filters based on performance criteria. If the filter fails to provide the necessary control of damaging-sized particles, then their presence in the system will lead to a substantial increase in the number of particles generated within the system through a chain reaction of wear.
What value is most appropriate? The current data requirement is a substantial improvement.
Clarifying the New ISO Contamination Filtration Standards
It is only when the ratings at higher Beta ratings are considered that the differences in performance are clearly seen. The data that can be made available is as follows:. Users were often confused when comparing performance data of seemingly identical filters.
The filter should control the fluid cleanliness to a level that is equal to the performance, life and reliability of the system required by the user. The Beta ratio is defined as:. Create your own user feedback survey. It also enables the user to discriminate between uso that achieve the desired control and those that do not.
166889 changes in the ISO multi-pass test method and associated standards provide greater precision in measurement. A filter must control the levels of all contaminant particles at and above the size critical to its operating system.
Toggle navigation Toggle search. The group also stipulated that detailing comprehensive performance data was necessary so iiso can make informed selections. When the contaminated hydraulic fluid passes through the filtration medium, it takes the line of least resistance.
Hydrauliköl-Filtrationssysteme | Donaldson Hydraulik
While primarily developed for fluid power, the new standards are equally applicable to the lubricating isso sector. The slope of the curve effectively defines the pore size distribution PSD of the filtration medium; the wider the PSD the less able the filter is to control those critically sized damaging particles.
To appreciate the importance of the filter in the management of the system, consider the primary function of the filter: Users of filters have historically liked the simplicity of a single point rating the size where a specified Beta ratio is attained.
The need to remove particles consistently across a wide size range was recognized by the ISO Working 1889 responsible for updating the multi-pass filter test.
It is a preselection requirement that provides the user and specifier of filter standards with more consistent information. Therefore, the highest Beta ratio that can be reliably measured should be selected. The Best Gets Better: Additionally, the user can have greater assurance and confidence in the data, and designers or specialists can make a more informed judgment in the selection of the most appropriate 168899 for his system.
This gives a series of Beta ratios for the filter as opposed to ios percentage efficiency. The Role of the Filter To appreciate the importance of the filter in the management of the system, consider the primary function of the filter: More detailed information from the test has to be published than previously required. Therefore, the desired level of control will not be achieved.
About the Author Mike Day. These standards have been developed to increase the precision in the measurement of contamination and filtration performance, and to extend the amount of information from the tests. Current Issue Archive Advertise. The more critical the system, the stronger the filter element and the more frequent the isl required. The data that can be made available is as follows: This makes the capture of isl particles, by the filter, essential to sustain the good health of the system.