Abstract: An inlet device is provided for providing a mixture of a less dense liquid component and a more dense liquid component to a separator vessel. The inlet device comprises an annular chamber and an inlet which causes the mixture to swirl around the axis of the annular chamber. As a result, a vortex is caused in the separator vessel as the mixture enters it from the inlet device. This vortex is used to separate the more dense liquid component from the less dense liquid component, with the less dense liquid component being forced to the centre of the vortex where it is removed via an outlet which runs through the centre of the annular chamber. The inlet device also comprises a gas distributor for introducing gas bubbles into the mixture before it enters the separator vessel, thereby improving the separation of the more dense liquid component from the less dense liquid component.