The process accelerates extremely and quantity of impregnating agent reduces evidently in vacuum becarse of the active action of vacuum mechanism to permeability and chemical reactivity of the agent in immersion media.

The solvent residual amount of extracted plant oil in Anhui province has been supervised by using gas chromatograph for three years,and the results show that the whole desolventizing technique and management level of oils and fats trade in the province are good,but the average residual amount of solvent is going up year by year.