| 摘要 |
<p>A silencer for use with an ultrasonic flow meter for measuring a stream of fluid in a pipe. The silencer is for reducing the noise in the ultrasonic range of frequencies caused by flow control valves and related equipment such that the wavelengths associated with the silencer are short with respect to the dimensions of the associated equipment. In one of various embodiments, a plurality of plates having apertures are provided. The apertures in the plates are sized and shaped for maximum passage of fluid and for minimum passage of noise in the ultrasonic range of frequencies caused by the flow control valves and related equipement. Alternate embodiments include off-setting plates, open-cell foam plugs, closed cell foam linings, off-line assemblies using visco-elastic absorbing material and semi-circular plates oriented in longitudinal relationship within the pipe.</p> |
