The Vaporizing Of Paraffin for High-Speed Motors
(Electric Ignition Type)

PETROL CARBURETTORS. 33 devised and tried to enable a high-speed motor to be run successfully on petrol and paraffin or paraffin alone, one example of each will suffice. Of these, the Gillet- Lehman (Fig. 28) is a single-jet car bure ttor depending on a variable barometrical depression over the contents of the float cistern t, by which the level of the liquid supplied to the nozzle S can be lowered from the maxi- mum lieight as shown, to such a level as will inerease the resistance necessary to compensate for an inereasing velocity of air flow around the nozzle. The drum throttle li, which is formed with a snail-sliaped core, is shown closed or nearly so, and the actuating lever pointing to S, in which position the surface of the petrol in the float cistern is exposed to practically the full atmospheric pressure ; also, with the throttle in this position, com- munication between the float cistern and the mixture supply or suction end of the carburettor, is cut-off from the passage m, as shown by the position of the groove g on the throttle stem ; but on rotating the throttle from S to 0, which is the full open position, the groove g will be gradually opened to the duet m leading to the float cistern, and will in consequence reduce the pressure therein, by reason of the communication straight through to the supply end—i.e., via c, v, g, and m—the exact depression required to produce the best effeet, as ascer- tained during the process of tuning up, is regulated once for all by an adjustment of the pi ug v, or its equi- valent. By rotating the throttle from the closed position to A. communication is opened up direct to the atmo- sphere, via the side port a1 and throttle port a~. By this construction, it will be seen that the surface pressure acting on the contents of the float cistern can be arranged 3