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Clean Oil - A Pre Requisite for any Hydraulic system
1. Importance of Filter
In hydraulic installation large volumetric flows pass through extremely small gaps and clearances at very high pressures. This means that such an installation is considerably more sensitive to dirt and contamination in the hydraulic oil, above all solid particles, than is the case with other types of machinery.

Experience has shown that more than 50% of the premature  breakdowns that occur in hydraulic installations are due to contaminated hydraulic fluid.

It is the task of the hydraulic filter to reduce this dirt and contamination to an acceptable as regards that size and concentration of the dirt particles concerned. This provides protection against premature wear of the components and assemblies.

2. Defining the degree of contaminations
The size and concentration of the dirt particles is quoted when defining the degree of contamination of hydraulic fluid. Counts have proved that the frequency of breakdown increases along with a reduction in the size of the dirt particles.  3 The effect of contamination The contaminant particles can be grains of sand, small pieces of metal or rust, dust etc. These aggravate the abrasion wear in the hydraulic components of those parts that move relative to one another and also in the seals and gaskets. Particularly affected by abrasion due to contamination are, for instance, the bearings, vanes, gears and pistons of hydraulic pumps and motors, as well as the pistons, piston rods and bushings of working cylinders. The abrasion wear on the sliding surfaces increases the clearances and results in higher internal leakage, qualities can also cause metal erosion at valves and on control edges, seating surfaces, restrictions and throttles. Solid, non-abrasive, foreign matter originating from seal wear, filter materials, textile fibers and flakes of paint etc. can cause breakdown and trouble by blocking passages, channels, gaps, lines and filters. Such non-abrasive foreign matter can also cause valves to jam.

Relatively large (>50 um) solid-matter particles often cause sudden machine breakdown shortly after the installation has been taken into operation for the first time. Contamination due to smaller particles (<10 um), on the other hand, generally causes gradual wear with the accompanying slow development and appearance of the resulting wear and damage.

The damage caused by solid contaminant particles depends upon their hardness, size and concentration, as well as upon the sensitivity to dirt of the component concerned. Particularly high levels of wear are caused by those particles of solid matter whose size approximates to the clearances between moving parts. Modern design & for high pressures are more sensitive to dirt than are their lower-powered counterparts. This is due to the tighter clearances and higher loading of the lubricating film on the high-pressure equipment.

It is possible to apply special constructive measures to reduce the harmful effects of contamination and therefore increase service life. For instance, self-adjusting gaps can be used, or specially paired materials, the overall result being a certain level of 'self-healing' at the damaged components.