Abstract: An apparatus for removing entrapped gas and selectively removing and detecting particles above a predetermined size in an oil lubrication system is described. The oil enters tangentially at the top of an outer cylinder and is caused to cyclonically work its way down to the bottom of the cylinder. The oil is then forced to reverse its flow and travel up along an inner cylinder. The centrifugal force fields created by such flow cause entrapped gas to coalesce in the center of the flow pattern from which point it can be vented from the system. It also causes heavier particles, which are used by the apparatus to detect impending failure, to be thrown out of the flow pattern into a detection cavity positioned at the bottom of the outer cylinder at its periphery while lighter particles remain suspended in the fluid. A conventional magnetic sensor is contained within the cavity to capture the separated particles for subsequent removal from the system and signal their presence to the operator of the system.