working priciple: 1) The filtration method is to add leaching solvent continuously into the rough powder of medicine material to make it filtrate the medicine powder, and then the leaching liquid will flow from the bottom outlet. 2) During the filtrate, the solvent will filter into medicine material to dissolve large amount of soluble matter and the concentration will increase, it will move downward after the density increase. 3) The leaching solvent at the upper layer or the thin leaching liquid will change the position and produce, which will make a good concentration difference to make the scattering be carried out smoothly. 4) Thus, the leaching effect is better than the dipping method, and the extraction will be comparatively complete. structure and characteristic: The equipment is composed of tank body, taper type, oval seal head (or flat cover), pneumatic slagging door and operation bench etc. It has such characteristics as equal solvent distribution and convenient slagging etc.