In the past, it was generally repaired in this way: electric welding repair and reprocessing for dynamic balance or thermal spraying repair. Because there were few domestic roots blower enterprises at that time and the price was high, maintenance was the most cost-saving method. Now that the impeller is worn, we usually replace it with a pair of new impellers or a new machine directly, and the cost is almost the same. Now there is no repair value for impeller wear, because the new machine is too cheap.