Product Short Description: Separatory funnel, or step funnel, is a laboratory glassware used in liquid extractions to separate (partition) the components of a mixture between two immiscible solvent phases of different densities. Product Description: A separating funnel, also know as separation funnel, separatory funnel, or step funnel, is a laboratory glassware used in liquid extractions to separate (partition) the components of a mixture between two immiscible solvent phases of different densities.