| 摘要 |
An extractor fan comprising a housing 3 fitted in an opening of a building from which air is extracted. Fan 5 comprises a motor 81 driven impeller 71 delivering an air flow through the housing, a flow sensor 97 sensing flow through the housing, and a flow indicator 101, 103, 105 providing an indication of the sensed flow through the housing. The housing may comprise a body 21 including an aperture 23, and a duct 24 extends from the aperture, and a support 28 supporting the fan. The support may comprise a platform 29 coaxial with the duct and a plurality of planar radial web elements 30. A planar cover 7 may be fitted to the body. The impeller may be an axial, radial or hybrid impeller and comprises a hub 77 and a plurality of blades 79. A control unit 91 controls operation of the motor. The sensor may be a velocity or pressure sensor. The indicator may comprise a display 101, a display element 103 (LCD or LED) and an optical element 105 having a reflective surface which may be a right angle prism, or may be a transmitter connected to a wireless handset. |
