In traditional Chinese medicine extraction, the extraction tank mainly relies on solvent circulation and vacuum concentration to dissolve active components. After the herbal material is loaded into the tank, 5 to 10 times the amount of solvent is added according to process requirements, commonly water, ethanol, methanol, or acetone. The tank heating system is started to heat the extraction liquid to boiling and maintain it for 40 to 60 minutes. The extract is then drawn out by a vacuum pump and transferred to the concentration tank.
The extraction tank heating system is turned off, and the concentration tank heating system is started. The concentration temperature is maintained at about 80°C, and the vacuum level is kept between -0.05 and -0.08 MPa. The secondary steam generated during concentration is converted into condensate through the condenser and cooler. This condensate can be returned to the extraction tank as fresh solvent, flowing downward through the herbal material layer to continuously dissolve soluble components.
After the extract enters the concentration tank through the filter pipe, the secondary steam from concentration is sent back to the extraction tank, forming a circulation of fresh solvent reflux extraction until the active components in the herbal material are almost fully dissolved and the extract becomes colorless. Concentration then continues until the extract reaches the required density as a paste. The colorless liquid remaining in the extraction tank can be stored and reused in the next batch.
The entire process uses repeated solvent circulation and vacuum concentration to reduce solvent consumption and improve extraction efficiency. For non-standard parts such as filter pipes, reflux connectors, and seals on the extraction tank, we can provide single-piece or small-batch machining according to customer drawings.
