Usage of glass distillation unit: clean the instrument and fix it with iron frame. If the bottom of the flask is heated by gas or electric furnace, an asbestos net shall be padded, and the volume of the liquid put into the flask shall not exceed 2 / 3 of the volume of the flask. Before distillation, the cooling water source shall be connected first, and convection shall be formed from the lower nozzle to the upper nozzle, so as to improve the condensation effect. After the condenser tube is cooled, it flows into the receiving bottle to achieve the purpose of separation or purification. It should be noted that the angle of the instrument should be appropriate in the process of assembling and pulling, and the instrument should not be installed or disassembled under the condition of angle deviation, otherwise it is easy to damage the instrument.