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).
Leaflet describing the principles, construction, and operation of the 'Orkan' carburetor for motorcycles.
| Identifier | ExFiles\Box 122\4\ scan0041 | |
| Date | 11th September 1927 guessed | |
| ORKAN PRINCIPLES When motor-cycling became popular the little air-cooled motor was employed in a large measure, and constructed in a special way, so that all accessories were to be adapted to the new construction. As it was necessary to use fuel-oils of relatively great specific gravity a single spraying of the fuel was not sufficient. To a modern carburetor two chief requests are made: on the one hand it must be absolutely flexible, and assure great performances in the high speeds, whilst, on the other hand, it sprays the fuel several times by means of a most simple automatically working device. In order to meet these requirements the principle of the variable sprayer which had proved a great success in the construction of automobile-carburetors, was also employed in motor-cycle-carburetors, and the „Orkan” carburetor for motor-cycles was built. This variable sprayer, representing a combination of the throttle valve with the atomizer, was built as a unic device for the formation of the mixture, according to the results of a series of careful tests, by which the most simple and efficient form was found. This form implies many advantages, the most remarkable of which are: smooth, economic working and better efficiency of the motor, most simple manipulation of the single adjusting lever, and easy exchange of the nozzles without loss of fuel. In spite of its most simple construction the „Orkan” carburetor for motor-cycles comprises all the advantageous devices which are requested of a modern carburetor. Longitudinal Section DESCRIPTION The „Orkan” carburetor for motor-cycles is composed of a horizontal throttle case 2 and a float chamber 6 arranged centrally on its top, the latter having the shape of a bell and containing the annular float 7 which, by means of a valve 15, maintains a constant fuel level 8, and may be depressed by the spring diver 14; the bell-shaped nut 9 holds the float chamber against a soft packing 5. This arrangement permits of the bell being turned until the fuel tube can be favourably fixed in the connection nipple. Openings in the bell-shaped nut and the bell-shaped cover set the float chamber in communication with the atmosphere. The fuel nozzle 12 supports, in its head-part, the air nozzle 11 and holds the bell-shaped cover at the same time. Through 2 openings it communicates with the fuel in the float chamber, descent tube 10 entering its central bore and being held against the walls of the throttle case, and the upper surface of this tube being above the level of the fuel. The descent tube communicates with the bore of the hollow throttle-axle 3, on which the throttle 4 is held by a tapered pin, the throttle communicating with the hollow axle through channels. On the lower rifled end of the axle an adjusting lever 17 is pindied. By means of a closing spring the adjusting lever tends to turn the throttle to its closed position, this position being determined by a stop. The springheld rod for running light 18 enters, with its cone end, a restriction of the axle-bore, a crusted nut 1 allowing the rod to be adjusted. WORKING The fuel coming from the fuel tube enters the connection nipple, passes through the valve seat, and flows alongside the flat valve to the float chamber where its constant level is maintained by means of the annular float. Through the openings in the lower part of the fuel nozzle it enters the nozzle and rises in the same and in the surrounding space to the fuel level in the float chamber. SIMPLICITY ECONOMY SUPPLENESS | ||