Abstract: The invention concerns a method of operating a particle sensor and evaluation of a result. A method of operating a particle sensor and evaluation of the results thereof comprises at least the following method steps: determining the frequency of the particle occurrences by means of the particle sensor; and signalling the exceeding of a predefinable threshold value, determined from the maximum particle number detected per time interval.

Abstract: A filter apparatus (10) for cleaning functional fluids, especially selected from phosphate esters, phosphate ester-based oils, mineral oils and phenols, includes a filter housing (12) into which a filter bed (14) has been introduced. The filter bed has a mixture of anionic and cationic ion exchange resins. At least one filter element (16), designed as a flow guide device, enables the diversion of the fluid from a radial to an axial flow direction (18) or vice versa.

Abstract: A method and a device detects contaminants in a fluid (1). Fluid (2) with particles is conveyed by a first metering pump (3) to a device (4) for measuring the contamination or the particle density in the contaminated fluid (2). Before entering the device (4) for measuring the contamination, the fluid is mixed with cleaned fluid (5) in a defined mixing ratio. The particle density or the contamination of the mixed fluid (6) is measured. The particle density or the contamination of the contaminated fluid (2) is determined by an arithmetic unit (7).

Abstract: The invention relates to a method and a device for detecting contaminants in a fluid (1), wherein the fluid (2) that is contaminated with particles is conveyed by a first metering pump (3) to a device (4) for measuring the contamination or the particle density in the contaminated fluid (2). Said method and said device are each characterized in that, before entering the device (4) for measuring the contamination, the fluid is mixed with purified fluid (5) in a defined mixing ratio, the particle density or the contamination of the mixed fluid (6) is measured, and the particle density or the contamination of the contaminated fluid (2) is determined by an arithmetic unit (7).