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).
Descriptive leaflet for the Orkan carburetor, detailing its principles, components, and mode of operation.
| Identifier | ExFiles\Box 122\4\ scan0039 | |
| Date | 11th September 1927 guessed | |
| ORKAN PRINCIPLES The progressive development of automotive vehicles and their utilization for economical purposes had as consequence an increasing demand for small cars. In the course of this development it became necessary to design a carburetor for the applied motors standing against the highest requirements of modern motor engineering, but being low-priced and not difficult in attendance. A carburetor which pretends to fulfill these conditions must, therefore, secure perfect and automatic spraying of each usual fuel at every speed and load of the motor, whilst all parts liable to get dirty are well accessible, the carburetor permitting to be easily operated by owner-drivers. These features have been the leading principles in the construction of the „Orkan“ carburetor, and they have been realized in a most simple way, with the combination of the throttle with the sprayer in one unit. By this arrangement a variable sprayer was built which — in all positions of the throttle — sprays the mixture of fuel and air a second time at the point of the highest speed of the gas. The perfectly sprayed and tightly mingled mixture secures better flexibility and performance of the motor at reduced consumption. Owing to its stout construction the „Orkan“ carburetor wants only a minimum of space without diminishing the accessibility of its parts. The nozzles and air inlets, for instance, may be changed by simple manipulations without loss of fuel. For the easy starting of the motor a rotative shell is provided, and may be engaged by means of a gear leading to the driver’s seat. DESCRIPTION The chief part of the „Orkan“ carburetor for small cars is the main casting, the mixing chamber 3 on which the bell-shaped float chamber 18 is seated. In the mixing chamber the throttle 4, provided with outlets of various sizes, is fixed by a tapered pin on a hollow axle 5, a stop lever being secured by a springheld stop screw 2 on the square head of the axle. An adjusting lever 23 is pinched to the stop lever so that it may be turned horizontally to any position. Simplicity (Diagram with labels 1 to 24) figure 1 The springsupported needle 24 for running light extends through the bore of the throttle axle, its cone end being seated at the point where the said bore diminishes in size. By screwing off the spring-pressed crusted nut 1 the running light may be retracted from its seat. The upper end of the axle bore opens to the descent tube, this tube being pressed against the walls of the mixing chamber so as to form an air-tight connection. The float chamber above the mixing chamber receives the float 16 which is pivoted on the float axle 7, and maintains a constant fuel level by means of a tapered valve 9, the lowering rod 10 permitting to make the float dive. Economy ORKAN The bell-shaped nut 14 presses the float chamber against a soft packing 6 which is fitted into an annular recess of the mixing chamber, this arrangement permitting the bell to be adjusted to any desired position. On the bell-shaped nut an elastic cover is provided to prevent the spilling of fuel when the car is jolting. Into the external chamber of the fuel nozzle 13 calibrated holes open at its upper and lower ends respectively, and set the chamber in communication with the atmosphere and the fuel in the float chamber, an air-inlet 12 being screwed into the head-part of the fuel nozzle and the hexagon head of said arie supporting the elastic bell cover in its position. The fuel pipe is connected with the carburetor by a duct soldered into the pipe of tapered inner surface 8 and held in its position by a screw-cap. The air-intake 19 has its seat in a recess of the mixing chamber, and is secured by the rotatable suction shell 20 which is pivoted on the screw-bolt 21, the shell being retained in its opened position by a spring 22, and this position being determined by a stop. MODE OF OPERATION The fuel arriving from the fuel pipe enters the connection nipple, flows through the valve seat, and travels alongside the flattish valve rod into the float chamber, where its constant level is maintained by means of the an- nular float. When the motor is running the depression makes air entering through the air inlet, raises the fuel above the upper opening of the descent tube, and draws the resulting mixture of fuel and air through the descent tube into the main bore of the throttle axle, where said mixture is divided according to the respective opening of the throttle. Suppleness | ||