Disclosed in the present disclosure is a method for extracting and separating various components from flaxseed meal based on a subcritical composite solvent, including the following steps: adding an extraction agent to flaxseed meal for subcritical extraction to obtain a crude flax lignan extract and crude flaxseed oil in one step, where the extraction agent includes n-butane and anhydrous ethanol at a volume ratio of 1:1; adding n-hexane to the crude flaxseed oil for fractional extraction, and conducting rotary evaporation to obtain flaxseed oil; and subjecting the flaxseed meal used to hot water extraction to obtain flaxseed gum. In the present disclosure, the subcritical composite solvent used in an extraction process can replace a large number of organic reagents used in a traditional extraction process, and has the characteristics of good solvent effect, environmental friendliness, recyclability, and low burden on the environment.

A rotary evaporator includes a sample flask having a reservoir for receiving a sample and a neck in communication with the reservoir. The neck extends along an axis and a purge tube extends within the neck of the sample flask along the axis. The purge tube includes a distal end and at least one opening formed in the purge tube at the distal end, the distal end being closed. Purge gas is supplied to the purge tube and injected into the sample flask via the at least one opening. The purge tube is movable along the axis via an actuator, between a retracted position, where the distal end of the purge tube is situated in the neck of the sample flask, and an extended position, where the distal end of the purge tube is situated in the reservoir of the sample flask.