FILTER AND METHOD FOR FILTRATION OF HYDRAULIC OIL IN A RETURN LINE TO A HYDRAULIC TANK, AND A DRILLING RIG COMPRISING THE FILTER

摘要

A filter (5) for a return line (L1, L2) for hydraulic oil to a hydraulic tank (2), which filter (5) has a filter element (11). The filter (5) is arranged to filter the hydraulic oil through the filter element (11) when the hydraulic oil is below a first oil level (H1) in the filter (5), and the filter (5) has an arrangement (15) to cause the hydraulic oil to bypass the filter element (11) when the oil level (H) in the filter (5) exceeds the first oil level (H) without causing any significant back pressure.