The NBD-B type epitaxial furnace exhaust gas purifier developed by our company adopts a comprehensive structure of 2 spray washing chambers and 1 packing column chamber. The negative pressure generated by the washer is manually controlled, and the water replenishment system is adjusted manually according to the process conditions. The removal rate of water-soluble gases is as high as 99.99%. The highest purification efficiency, the most convenient maintenance, and the lowest operating cost.