These extractors are the most basic of hydrocarbon extraction system. You simply add material and run solvent through the column while it escapes at the other end. Open blast extractors are best for small runs for personal use, or for testing material.
These small extractors are not meant to reclaim solvent. Please check with your state and local laws to see whether open blase systems are legal in your area. Always use open blast systems outdoors, away from any source of ignition, and with plenty of airflow.