The rubber disc 6 has a bell shape with a circular hole in the center, and the outer edge 17 of the bell shape has a flange 18. The movable pallet 7 is a disc, which is sleeved on the air duct 5; there are two protruding rings 19, 20 with different diameters on the disc. The two rings 19, 20 are just in line with the rubber plate 6 The outer edge 17 and its flange 18 match the groove; the outer edge of the movable support plate 7 falls on the outer edge of the plate body 8.
The plate body 8 has a positioning screw 21, a hexagonal body 22, and a thread 23 at the bottom to connect with the air supply pipe. When assembling, after adjusting the contact pressure between the movable support plate 7 and the disc body 8, the air duct 5 and the disc body 8 are fixed with the positioning screw 21 to ensure the good aeration quality of each waste water diffuser. The hexagon 22 at the lower part of the plate body 8 is used for wrench assembly and disassembly.