Filter Fibel - MAHLE - #39

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Fig. 51: Contamination indicators for different filter series stays in, then the element is fully functional, how-ever if it does not stay in, then the element must be changed, at the latest after the shift ends. Electrical displays also provide an electrical signalin addition to the visual display. The red pin and thesignal are independent of each other. Here as well, the level of contamination should be evaluated when the equipment is warmed up, because a cold start can trigger a contamination signal due to the increased viscosity. Consequently, a cold startsuppressiondevice can be useful for equipmentthat frequently starts at lower temperatures. Elements must always be changed with the utmost caution and in strict compliance with the operating instructions. Cyclical monitoring of the contamination With focused monitoring, filters are also suitableas wear control instruments for hydraulic system components. For instance, if the operator regularly documents filter replacement, then increasingly shorter replacement intervals are an indication that component wear is increasing. Qualititative andquantitative analysis of the element and a fluidsample from the system make it possible to locate the origin of the contaminant particles and thus localize the cause of the increased wear. Hence, inferences are possible relative to the installedmaterials and thus preventative repair interventioncan be executed before total failure and production downtime occur. Generally, quantitative contaminant determination of hydraulic fluids that is carried out anyway serves this objective. Samples taken atone of the specially designed removal points, orcaptured via online particle measurement, ensure that the required contamination class is maintained and that the system thus remains functional. Changing elements If the contaminant display shows a contaminatedelement, then usually there is at least 8 hours ofreserve capacity, i.e. there is reserve capacity for the duration of a shift. Thereafter the filter ele- ment must be replaced. If the filter element is not changed, then in extreme cases the element couldcollapse with fatal consequences: Contaminantsthat have already been retained are abruptly washed into the system through the torn filter matrix – this often results in a total failure. The following filter control guide values apply forfilters without contamination indicators: 24 hours after commissioning the equipmentAfter the run-in phase (50–100 operating hours) Normal service (300–500 operating hours)
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