From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Press cuttings and an advertisement regarding the 'Servais Silencer' for reducing vehicle exhaust noise.
| Identifier | ExFiles\Box 152\3\ scan0219 | |
| Date | 6th August 1936 | |
| INTERNATIONAL PRESS-CUTTING BUREAU 51, RED LION STREET, HIGH HOLBORN, LONDON. W. C. 1. Extract from "CAPITAL" (ESTABLISHED 1889) Date 6 AUG 1936 SEE ALSO OVERLEAF. Silencing of Motor Vehicles An invention which, it is claimed, will revolutionise the silencing, not only of motor vehicles, but also of aeroplanes, machine guns and submarines, was demonstrated recently in London. Known as the Servais Silencer, and manufactured by Servais Services, Limited, of 8, Old Pye Street, Westminster, S.W.1, the apparatus can be attached to the exhaust pipe of a motor vehicle so as to render the exhaust almost inaudible. During the demonstration it was used on an engine having a penetrating exhaust note, with satisfactory effect. It is already in use on public vehicles, including motor sweepers used by the City of Westminster. The principle of the silencer is absorption of sound frequencies over any desired range, and thus it is adaptable to a large variety of purposes. Servais DURRANT'S PRESS CUTTINGS St. {Capt. P. R. Strong} Andrew's House, 32 to 34 Holborn Viaduct, and 3 St. {Capt. P. R. Strong} Andrew Street, Holborn Circus, E.C.1. Telephone: CENTRAL 3149 (Two Lines). British Trade Review 52 Fetter Lane, London, E.C.4. Cutting from issue dated JUL 1936 193 Silent Motor Traffic. A demonstration was recently given in London of an invention which, it is claimed, will revolutionise the silencing of motor vehicles. The Servais Silencer, as the new device is called, permits the exhaust gases to have an unrestricted passage, for it has no baffle-plates, and to all intents and purposes is a "straight-through" silencer. At the demonstration, the silencer was tried on such widely different machines as a "Flying Standard" saloon, a Frazer-Nash sports car, and a motor cycle. Two motor cycles were on view—one with the normal silencing arrangement, and the other with a Servais instrument. The difference was most marked. The Servais silencer is already in use on public vehicles. For several months motorists in Westminster have been astonished by the dead-silent running of the City of Westminster's night-sweepers. This silence has been obtained by fitting Servais silencers to the whole fleet, with the result that residents are now able to sleep undisturbed while their streets receive their nightly sweeping. The silencing of Diesel engines is extremely difficult, as is well known, and it is understood that the Associated Equipment Company is submitting the Servais silencer to stringent tests with a view to fitting it on the London Transport buses. MOTOR COMMERCE THE MOTOR TRADE MONTHLY Editor - PERCY PETERS. Manager - W. B. S. WEDDALL. THE Proprietors have the pleasure to send the annexed cutting from the July number which they trust will interest you. Editorial and Publishing Office: 18, Bedford Square, London, W.C.1 Telegrams: "Ommercomot, Westcent, London." Telephones: Museum 2845-6. Reducing Exhaust Noises The Servais silencer for obtaining all the advantages of a straight-through exhaust with absolute silence, or degrees of silence varying from complete inaudibility to a deep, pleasing burble. Q 2005 1,000 Claims : Ensures reduced petrol consumption, less carbon deposit, increased power, cooler running, reduction of maintenance costs, prevention of panel drumming, and absolute silence or a deep but soft note, whichever is desired ; design based upon scientific facts ; absorbs sound frequencies over any desired range ; all British ; more effective than ordinary straight-through exhaust-pipe ; impossible to produce better silencer. Construction : Instead of baffle-plates housing incorporates special porous filling built-up of constantly varying cells, with an entirely free central passage through which the exhaust gases pass without any form of obstruction. Principle : Absorption of sound frequencies over any desired range by arranging the cells of the filling so that they vibrate within the casing, synchronisation of cell and sound vibrations of exhaust gases serving to make the passage of the gases inaudible. Comparative Data : Showing the power increase and noise reduction consequent upon reduction of back pressure when a Servais silencer was fitted to a certain engine, as follows : r.p.m., 3,500 ; b.h.p., 55.6, 53.5 and 50.6 for Servais ; American and baffle-plate silencers giving 1.7, 2.0 and 3.9 lb. pressure per square inch back pressure and 65, 80 and 92 phons (noise units) respectively. Prices : From 27s. 6d. Manufacturers : Servais Services, Ltd., 8, Old Pye Street, London, S.W.1. | ||