An inlet device for use in a vessel to facilitate separation of a gas phase from a liquid phase in a fluid stream. The inlet device has separation cans positioned at each of the outlet ends of a flow channel. Each separation can has a cylindrical wall and an elongated inlet opening in the cylindrical wall to allow the fluid stream to be introduced in a tangential direction into an open interior region where it swirls to facilitate separation of the gas phase from the liquid phase in the fluid stream. The liquid phase exits the separation can through slots in the cylindrical wall and through an open lower end of the open interior region. The gas phase exits the separation can by ascending upwardly through an open upper end of the open interior region.