Abstract: A method and an arrangement in a circulation lubrication including a lubricating oil tank, pressure pipe lines for supplying oil to parts to be lubricated, and return pipe lines for returning the oil from the parts to be lubricated to the oil tank. To remove air and dirt from the oil, the flow returning from the parts to be lubricated to the lubricant tank is divided into at least two superimposed flow portions, using a plate member, so that the oil flow portion containing air bubbles forms the upper flow portion and the flow portion containing water and heavy particles forms the lower flow portion.

Abstract: A method and an arrangement in a circulation lubrication system including a lubricating oil tank; pressure pipe lines for supplying oil to parts to be lubricated; return pipe lines for returning the oil from the parts to be lubricated to the oil tank. To eliminate problems caused by moisture, a blower is arranged to blow air into the oil tank, and at least one valve is positioned in the oil return pipe lines, the valve being arranged to allow the discharge of the air blown into the oil tank and the air with moisture and dirt flowing in the return pipe lines from the oil return pipe lines.