ULTRA FINE HIGH EFFICIENCY FILTER

摘要

Filter device (20) comprising a set of coaxially filter elements (1, 3) within a filter devise housing having an oil inlet port, and an oil outlet port (18), a first, upstream filter (1) being a full flow filter through which all of the inlet port oil passes, and second, downstream filter (3) being an in-depth micro-filter through which only part of the oil passed through the first filter (1) passes to the outlet port (18), the remainder of the oil filtered by the first filter (1) by-passing the second filter (3) towards said oil outlet port (18). The by-pass (11) is realised by an pressure dependent by-pass valve (8, 8A, 10, 12; 12A, 12B; 13) , opening during normal operation of the filter device (20) at a pre-set oil pressure level (dPr) within the oil compartment (2) between the said two filter elements (1, 3).