By using a bottom flood on the first wash to ensure all material has seen solvent, preventing channeling through the material. Finish the run with a top flood input to ensure all residuals have been washed from the material.
Oil bearing solvent is collected in the collection base under the material column. The Athena is equipped with a nitrogen assist to prevent solvent from getting hung up in the material column. Once collected, solvent is distilled and recovered, leaving the oils in the collection base.