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).
Brochure detailing the principles, description, and features of the 'Orkan' universal carburetor.
| Identifier | ExFiles\Box 122\4\ scan0043 | |
| Date | 11th September 1927 guessed | |
| ORKAN PRINCIPLES The large circulation the automobile found in the last few years, the improvements in the construction of the employed internal combustion engines, and the necessity to use heavy fuel oils of inferior quality have greatly influenced the modern carburetors. A well devised carburetor must permit of being fitted and adjusted in a most simple way, without special tools, by owner-drivers having no special experience. These requirements served for guidance to the inventors of the „Orkan“-carburetor. In the course of long and careful theoretical investigations the solution was found in the principle of the combination of the atomizer with the throttle valve; by this arrangement a variable atomizer was built supplying automatically an even, perfectly sprayed mixture for any throttle-opening, and for any load of the motor. This principle was systematically developed by some years practical tests, and improvements and simple means were achieved, which rendered the advantages of the new arrangement in the „Orkan“ carburetor prominent, so that in a short time it became fully approved by the experts of the line. An important problem in the construction of the variable atomizer was the determination of its preferable shape; it was solved in a most simple and really ingenious way. Several slits at different distances from the throttle axle are extending over the whole breadth of the stream-line shaped throttle, so that broad veils of mixture are poured automatically into the suction pipe at the point where the gas passes in highest velocity, and the spray flows from the throttle straight to the motor. In order to increase the effect of the depression a jet cooperates with the atomizer, the jet adding a second quantity of air to the mixture before the latter enters the throttle axle. By these most simple means a repeated spraying of the fuel and mingling with the air, is attained. As this is realized in every position of the throttle the same effect is obtained as if there were a special carburetor instead of any position of the throttle, whose effect were to be equal to the effect of the throttle in the respective position. The throttle pipe is movingly connected with the float chamber, and may be turned to any desired position: horizontal or vertical, at right or left (in the direction of motion). This possibility of universal adjustment of the „Orkan“ carburetor justifies the name Simplicity ORKAN Universal-Carburetor. The arrangement of the fuel nozzle in the axle of the float chamber prevents any noxious effect of the centrifugal power when the car is driven on looped ways. The movable connexion with the float chamber of the throttle pipe permits of the float chamber being arranged before the throttle pipe (in the direction of motion), so that when the car is climbing uphill a somewhat richer mixture is automatically supplied, whilst when it is moving downhill a poorer mixture is delivered. Though it seems as if the arrangement of the nozzles is somewhat complicate the fuel nozzle is well accessible. The support of the float lever is another important peculiarity of the „Orkan“ carburetor. Remove the float lever from its support, turn the float by 180° and fasten the lever again to its support, so that the reverse of the lever is visible. By this inversion of the float lever alterations of the fuel level, caused by the use of fuels of different specific gravity, will be paralysed, so that it is possible to use fuels of different specific gravity without changing the nozzles. Last not least we mention the starting gear with which may be operated by a Bowden wire leading to the switchboard. This device permits of the cold motor being started by enlarging considerably the opening of the jet for running light, without removing the motor cover, and without flooding the carburetor. When the starting gear is operated all particles checking the opening for running light will be removed. In spite of these different special devices on which the superiority of the „Orkan“ carburetor is based the whole apparatus is stout and well built, and its price is low, as a consequence of the modern organisation of our works, which assures at the same time highest precision in the execution of the „Orkan“ carburetor. Economy DESCRIPTION The universal „Orkan“ carburetor comprises 2 chief parts, independen from one another: The throttle pipe 3 and the float chamber 22, combined to an inflexible unit by a screw-nut 13 of conical contact surface. The atomizer (throttle valve) 8 in the throttle pipe is provided with some slits, valve screw 9 fixing it on a longitudinally pierced axle 10, on the one end of which the stop lever is held by a spring-pressed stop-screw 5, an adjusting lever 4 of 360°'s turn being pinched on the stop-lever. Suppleness ORKAN The stem 6 for running light, supported in its place by a spring, projects, with its cone-end, into a contraction of the hollow axle and is adjustable by means of the spring-supported, crusted nut 7, the tube 11 for running light leading from the contraction of the hollow axle to an elbow 14, and the elbow being in connection with the pond before nozzle 19, through an regularly opposed holes in the crossed part 27. Before the nozzle opens a hole pierced rectangular to the axle of the nozzle, ascension tube 26 being pressed against the hole by fuel inlet 25. The crossed part itself is pressed tight to the walls of the throttle pipe, by a rustproof steel-spring 15. Round the crossed part is the annular float 28 pending, movably connected with float lever 18 and maintaining the fuel level 20 by means of the valve 21. The nipple 24 with screw 23 as its axle may be turned to various positions for any horizontal application of the supply pipe. A cover 16 is set on the top of the float chamber, and held in its place by the screw 17, the latter being fastened in the cover by a securing-device. The holes 12 in the casing of the float chamber set the latter in communication with the atmosphere. The air tube 1 is held on the head-part of the throttle pipe by a screw cap 2, combined with a wide-meshed strainer, which may eventually be replaced by a heated connection pipe. Reliability | ||