| 摘要 |
A peripheral toroidal blower has a stripper consisting of a central block part and two curved vanes projecting one from each end of the block part and extending in opposite directions around the toroidal chambers to at least partially cover the inlet and outlet ports. The active surfaces of the stripper are of porous material whereby to provide a substantial reduction in blade passing frequency noises. The active surfaces may be of inherently porous material such as polyurethane foam or of a nominally closed cell plastics foam of which the active surfaces are made porous by machining or cutting. |
