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

The present invention concerns a filter (5) for a return line (L1, L2) for hydraulic oil to a hydraulic tank (2), which filter (5) comprises a filter element (11). According to the invention, the filter (5) is arranged to filter the hydraulic oil through the filter element (11) when the hydraulic oil lies below a first oil level (H1) in the filter (5), and the filter (5) comprises an arrangement (15) to lead the hydraulic oil past the filter element (11) when the oil level (H) in the filter (5) exceeds the first oil level (H1).