Removable silencer device for jet engines

967,800. Silencers. SOC. BERTIN & CIE. Sept. 14, 1961 [Sept. 30, 1960], No. 32983/61. Heading F1B. In a jet engine removable silencer device the jet outlet 1, Fig. 1, discharges into the upstream end of a first conduit 7 which opens out at the downstream end to discharge all the exhaust gases into at least one flattened portion 8, the first conduit being surrounded by a second conduit 2, having a sound-proofed wall, which is open upstream to collect air and extends beyond the downstream end of the first conduit, the second conduit having a grating 16 to homogenise the mixture of gas and air. Jacks 14 are adjusted to engage cap 9 with outlet 1. Exhaust gases draw in air between bosses 9a and through space 13, the mixture being divided and damped by grating 17. In nozzle 8 the jet stream is divided into radial laminations which are surrounded by air from 2a. The conduit wall 2, Fig. 3, has felted-fibre cushions 3 held by longitudinal rails and spaced frames 5 and surrounding a perforated metal wall 22. The conduit 7 may have a similar arrangement.