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).
Advertising leaflet for the 'Servais Straight-Through All-British Silencer'.
| Identifier | ExFiles\Box 138\1\ scan0272 | |
| Date | 23th June 1936 guessed | |
| LESS PETROL LESS CARBON MORE POWER COOLER RUNNING REDUCED MAINTENANCE NO VIBRATION SILENCE SERVAIS STRAIGHT-THROUGH ALL-BRITISH SILENCER INCREDIBLE as it may seem, a ‘straight through’ exhaust is now obtainable with absolute silence—or degrees of silence— varying from complete inaudibility to a deep, pleasing burble. This is no wild statement—a demonstration of the new Servais Silencer can be given any time by appointment. There is, in fact, a free demonstration in Westminster every night. Try to hear the engines running on the Westminster City Council’s fleet of Night Sweepers! In this case they were fitted merely for silence. In every case, however, the fitting of a Servais Silencer will add the following list to the credit side of motoring. (1) REDUCED PETROL CONSUMPTION. The complete absence of back pressure ensures perfect scavenging of the cylinders, and results in a more complete combustion of the fuel, and therefore greater economy. (2) LESS CARBON DEPOSIT. Back pressure tends to retain carbon particles in the combustion chamber, thus forming a sooty deposit. As there is no back pressure with the Servais Silencer, these particles are blown straight through the exhaust system. (3) INCREASED POWER. During a bench test at a leading engine manufacturer’s works, the ordinary straight through exhaust pipe was removed, and a Servais Silencer fitted. Imagine the astonishment of the engineer-in-charge when the brake horse-power meter registered an increase of over 8 per cent, and the engine exhaust was completely inaudible. DESIGN AND CONSTRUCTION THE design of the Servais Silencer is based upon scientific facts and principles. It will absorb sound frequencies over any desired range. Its special porous filling is built up of constantly varying cells, with an entirely free central passage, through which the exhaust gases pass without any form of obstruction. These cells are free to vibrate within the casing, and by synchronising with the sound vibrations of the exhaust gases they finally entirely absorb them. It is All-British in every way, and is even more effective than an ordinary straight through exhaust pipe. We are quite safe in saying that it is impossible to produce a better silencer. PRICES FROM 27/6 PROV. PATENT No. 34072 WORLD PATENT PENDING (4) COOLER RUNNING. This is accounted for by the porous lining of the Silencer enabling the gases to expand quite freely and instantaneously. The result is an equal dissipation of the heat. During a test of the Servais Silencer at a Government laboratory, the temperature at the manifold of a big Diesel engine was reduced by 100 degrees. (5) REDUCTION OF MAINTENANCE COSTS. A much more even torque is immediately noticeable upon fitting the Servais Silencer. This eliminates the very considerable vibration which is set up by back pressure in an ordinary exhaust system; a vibration considerably greater than is generally imagined. The result of this even torque definitely reduces wear throughout the whole transmission system. (6) PREVENTING PANEL DRUMMING. Incessant panel drumming is a well known cause of fatigue, particularly on long runs. The drumming is caused by converting sound vibrations into physical vibrations, and is entirely unavoidable with a normal silencing system. The Servais Silencer completely absorbs both the physical and the sound vibrations. (7) SILENCE. Here again the Servais system is more effective than anything that has hitherto been available. We can definitely reduce the noise to practical inaudibility—or a deep, pleasing burble—as you wish, and this with a completely unobstructed straight through flow for the gases. SERVAIS SERVICES LTD., 8 OLD PYE STREET, WESTMINSTER, S.W.1 TELEPHONE: VICTORIA 0824 (OFF VICTORIA STREET) | ||