A centrifugal separator for cleaning gas

A centrifugal separator for cleaning gas containing contaminants comprising:

• a stationary casing, enclosing a separation space through which a gas flow is permitted;
• a gas inlet extending through the stationary casing and permitting supply of the gas to be cleaned;
• a rotating member comprising a plurality of separation members arranged in said separation space and being arranged to rotate around an axis of rotation,
• a gas outlet arranged in an upper portion of the stationary casing and configured to permit discharge of cleaned gas and comprising an outlet opening through a wall of the stationary casing;
• a drainage outlet arranged in a lower portion of the stationary casing and configured to permit discharge of liquid contaminants separated from the gas to be cleaned;
• and
• a drive member for rotating the rotating member,
• wherein an axial inner side surface of the stationary casing comprises at least one straight recess extending in an axial direction for accumulating oil that has been separated in said plurality of separation members,
• wherein said at least one recess comprises a first radial recess surface extending from the axial inner side surface of the stationary casing, and
• wherein said at least one recess extends axially on the inner side surface at least along an axial length of a radially outermost portion of said separation plurality of members.