GB730345A - Improvements in silencers for gaseous currents - Google Patents

Abstract

730,345. Silencers for gaseous currents ; filtering charge. AIR-MAZE CORPORATION. May 4, 1953, No. 12270/53. Class 7(2). An annular throat 19 is provided between the inlet end of a tube 22 lined with soundabsorbing material 23 in free communication with a stream of air or other gas, and a pad 33 of sound-absorbing material opposite and spaced from the tube, the throat having an area of the order of 100 to 150 per cent of the stream-traversed area of the tube. As shown, the tube 22 is secured to a plate 21 having an an outlet orifice 14 and is surrounded by a casing 16 supporting two arcuate filter elements 17 confined between plates 18 of expanded metal, a tube 27, covered with sound-absorbing material and concentric with the tube 22, providing a passage for lubricant pipes extending to the rotating parts of a blower or the like to which the silencer is affixed by the plate 21. The pipes pass through a skirt 36 which has a lining 39 of sound-absorbing material and is secured to an end wall 16a of the casing 16. The sound-absorbing material may comprise cotton or felt held in place by a screen of woven wire mesh or hardware cloth. In modifications, (a), Fig. 4 (not shown), a plate carrying the pad 33 is secured by spacer members to the inlet end of the tube 22, the tube being surrounded by an annular filter element and the tube 27 being omitted, and (b), Fig. 6 (not shown), one end of the tube 22 projects from a resonance chamber that end being surrounded by an annular filter and the area of the tube being about 70 per cent of the area of an outlet orifice of the chamber.