| 摘要 |
A diffuser comprises a plastic baffle 16 which has an air inlet end (12, fig.8b) an air outlet end (18, fig.8b) and an outwardly tapering wall 20. The baffle 16 defines a diffusing air chamber. A plurality of circumferentially spaced weld ribs 120 is upstanding from the air outlet end. A plastics grille 40 has a plurality of air outlets (42, 44, fig.3) and an annular shelf 122 to which the weld ribs 120 of the baffle 16 are ultrasonically welded. An outer wall 90 may have a second set of weld ribs 124 upstanding from spacers 96. These ribs 124 engage the underside of the baffle 16 and preferably allow the outer wall to be simultaneously joined with the baffle 16 and the grille 40. |
