GB408446A - Improvements in exhaust silencers - Google Patents

Abstract

408,446. Exhaust-silencers. BELS, A. H. DE, 205, Avenue Gambetta, Bagnolet, Seine, France. March 28, 1933, Nos. 9327 and 9328. Convention dates, April 1, 1932 and July 19, 1932. [Class 7 (ii).] An exhaust-silencer comprises a preliminary chamber communicating with intermediate chambers arranged in a casing so that an annular space is formed between the two latter, the preliminary chamber forming part of a continuous axial space, and the intermediate chambers only being in direct communication with the annular space. In the form shown in Fig. 1, the preliminary chamber comprises a central tube 1 communicating by holes 5 with conical intermediate chambers 4, which are arranged with their bases toward the exit end and communicate by holes 6 with the annular space 3 formed between them and the surrounding casing 2. In modifications, the tube 1 may be stepped, or surrounded by concentric tubes of decreasing length, and the chambers 4 may be spherical or ovoid and the last one of the series may be of double conical form ; also baffles or perforated screens may be fitted in the tube or the chambers. Further, the cross section of the ports in successive intermediate chambers may decrease towards the outlet. Fig. 7 shows another form, in which the first intermediate chambers 4b fit tightly within the casing 2 and are non-rotatably mounted on a central tube 20 which is open at both ends to the atmosphere to avoid excessive heat expansion. The exhaust gases may enter at 21 or by bifurcated passages ; or they may enter by an annular chamber fitted on the end of the casing 2, the end of the tube 20 being then bifurcated where it passes through the annular chamber. The gases may also impinge on an ovoid body as they enter the silencer. The last chamber 31 is perforated at 32 and communicates with an outlet tube 36, which is surrounded by an annular extension 34 of the casing 2. Helical channels or tubes may be fitted in the annular space 34, and a helical blade may be arranged within the tube 36, and these helical passages may be of varying pitch. Means may be provided for blowing air into the tube 20.