초록

A duct lining exposing a substantially smooth, liquid impermeable outer surface to fluid flowing therealong.

대표청구항 ▼

A noise attenuating duct lining comprising: a first lamina of relatively nonrigid air-permeable filamentary cloth which is substantially liquid impermeable at atmospheric pressure; a second lamina of relatively rigid perforate material secured to said first lamina to support the latter, said second

A noise attenuating duct lining comprising: a first lamina of relatively nonrigid air-permeable filamentary cloth which is substantially liquid impermeable at atmospheric pressure; a second lamina of relatively rigid perforate material secured to said first lamina to support the latter, said second lumina being fluid-permeable; a third lamina of means for defining a multitude of cells opening to said second lamina, said second lamina being secured to said third lamina and arranged to span the openings of said cells of said third lamina. The method of making a noise attenuating duct lining comprising the steps of: providing a first layer of air-permeable wire cloth, said wire cloth defining a pair of opposite faces, one of said opposite faces of said wire cloth being substantially smooth and impermeable to liquid at atmospheric pressure; providing a second layer of perforate metal sheet adjacent the other face of said wire cloth, said perforate sheet defining a multitude of spaced perforations communicating therethrough; electron diffusion bonding said first layer to and said second layer, providing a third layer of honeycomb structure, said honeycomb structure defining a multitude of cells extending therethrough, said multitude of cells opening at one end thereof to said perforate sheet; providing a fourth layer of imperforate sheet closing the other ends of said multitude of cells; and adhesive by bonding said second and said fourth layers to said third layer of honeycomb structure to seal said multitude of cells from direct communication with one another. Noise attenuating apparatus particularly for turbo machinery, said noise attenuating apparatus comprising a first layer of noise attenuating material said first layer communicating with a noise-containing environment associated with said turbo machinery; and a second layer of air-permeable and accoustically conductive fibrous cloth interposed between said first layer and said noise-containing environment, said fibrous cloth being substantially impervious to a liquid at atmospheric pressure from the group composed essentially of water, turbo machinery lubricating oils, turbo engine fuel oils, and combinations thereof, said second layer of fibrous cloth transmitting noise from said noise-filled environment to said first layer while substantially preventing transmission of said liquids thereto.