| 摘要 |
1512294 Centrifugal fans G FRIEDLING 10 Dec 1975 [16 Dec 1974] 50691/75 Heading F1C [Also in Division F4] A ventilator comprises a base 4 having a circular inlet aperture 10; guide blades 9 of flexible plastics material upstanding from the base 4 and defining therebetween directional outlets for exhaust gases; a cover 6 supporting a motor 1 for driving impeller blades 2 mounted on the blades 9; an annular collar 3 of flexible plastics material surrounding the aperture 10; and a sound-absorbing coating 16 of flexible plastics material integral with the collar 3 on the underside of the base 4. The directional outlets may be closed off by louvres as desired. The clearance between the guide blades 9 and an impeller of selected diameter may be adjusted by bending the blades as at 19 or by the use of clipon extensions 18. |
