A closed-loop system features a large tank with an attached tube, a recovery tank, a refrigerant scale, a refrigerant pump, and a recovery pump. To create essential oil extracts using a closed-loop system, an additional pump and recovery tank is also needed to create a vacuum and to re cycle the used solvent.
The additional equipment needed for essential oil extraction is used to purge the butane from the concentrate. A closed-loop system operates by packing the tube with fresh herbs. A pressurized solvent is then attached to the herb-filled tube. Various valves and clamps help ensure that the solvent remains pressurized during the process.
The solvent is allowed to pass through the herbs so the essential oils are pulled from the plant material. The concentrated oil is collected in a recovery tank. Although not without risk, a closed-loop extraction system is safer because flammable solvents are confined and cannot leak out to cause a possible explosion.
This is beneficial for pressurized liquids that become gaseous without pressure. With a closed-loop extraction system, chemical solvents can be reused, which saves money.