The air pump is an important filter supporting equipment to improve the filtration efficiency and strengthen the degassing effect. In order to ensure that the filter medium is not polluted, oil-free diaphragm vacuum pumps are generally used. This type of pump forms a vacuum through the reciprocating movement of the rubber diaphragm. The vacuum pressure is generally about 0.08Mpa (single stage). The key to increasing the filtration speed is The exhaust volume per unit time and the flow index of the vacuum pump are especially prominent when the filtration volume is large and the medium viscosity is high when the filter membrane is blocked by particles The service life of the vacuum pump depends not only on the correct use method (such as reducing ineffective continuous start-up; preventing the solution from being pumped into the pump body, etc.), but also mainly on the reasonable power of the motor, the design form of the vacuum membrane and its fatigue resistance. Diaphragm vacuum pump is advanced in design, compact and reasonable in structure, small in size, light in weight, easy to move, stable in operation, high in vacuum, low in noise, high in working efficiency and long in service life. According to the needs of the operator, it selects different materials and filter membranes with different filter pore sizes to achieve the functions of removing impurities in the solvent, purifying and sterilizing.