GB401485A - Improvements in silencing devices for gaseous currents - Google Patents

Abstract

401,485. Silencing gaseous currents. PAVILLON, A. F., Mamie Cottage, Avenue Duval Lecamus, St-Cloud-les-Coteaux, Seineet-Oise, France. Oct. 17, 1932, No. 28954. Convention date, Oct. 22, 1931. [Class 7 (ii).] The stream of exhaust or induced gas to be silenced passes through a pipe 4, Fig. 1, into a damping chamber 1, the length of which is many, e.g. ten, times its diameter, the outer end 2 of the chamber being closed. A discharge pipe 6 is provided at the inner end of the chamber. The stream of gas, in order to reach the outlet, has to change its direction of flow abruptly, and, as a consequence, the pulsations are separated from the stream and travel forward into the chamber 1 wherein they are damped by friction and reflexion. To assist in the frictional damping, the chamber may be filled with such materials as steel turnings, shavings, wool or rags. Further, its walls may have projections, as shown in Figs. 7 and 10, and a core with projections may be inserted, as shown at 22, Figs. 17 and 18. Other forms of projections are described and shown, and the chamber may be surrounded by a casing, the space between the two being filled with vibration-deadening material, Fig. 13 (not shown). The damping chamber may comprise a number of sections placed end to end, each section having one of the different forms of internal projection described, Fig. 19 (not shown). In Fig. 3, two damping chambers 1, 1a, with closed ends 2, 2a, are employed, the inlet pipe being shown at 4 and the outlet at 6. In a modification the pipes 4, 6 are within the chambers 1, 1a. In Fig. 5 a triple arrangement is shown, the damping chambers 1, 1a, 1b communicating with chambers in which the change of direction occurs. In all forms, the inlet and outlet may be interchanged. Applications of the silencing device to motor-cars, steam locomotives and aeroplanes are described with reference to Figs. 20, 21, 22, and 23 (not shown). In the case of an aeroplane, the damping chambers may be formed in the fuselage side chambers or the wing boom, and, in the case of motor cycles, the frame tubes may form such chambers.