摘要 |
A fluid flow passage defined by a surface which surrounds the passage is provided with a plurality of projections, such as fibrils or brush like bristles, on the surface extending transversely to the flow passage. The projections serve to counteract or dampen the generation of high frequency sound energy or noise. The flow passage may be part of a medical or dental aspirator or industrial vacuum intake system or high pressure steam or gas exhaust system.
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