Abstract: A device for the continuous separation of crude oil into its major constituent phases has no moving parts and is adapted for attacment to a pressurized conduit conveying said crude oil. The device, which operates in a substantially vertical orientation, is comprised of two concentric cylindrical chambers and an internal tube which conjointly define inner and outer annular spaces. A helical surface disposed within the outer annular space achieves isolation of a water/sand mixture which is expelled from the device. A series of contact surfaces located within the inner annular space separates oil from gas. The gas phase emerges from the internal tube. The oil phase exits from a lower region of the device.