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

14 VAPORIZING OF PARAFFIN. the lift of the valve as shown at t; the spray in some designs is fed to the under side of the valve to an air chamber, as shown in Fig 3, over the valve and thence to a spray nozzle s, this methocl enabling the valve to point stem downwards. The form shown in Fig. 4 is that usually adopted for motor-boat engines, the petrol supplied under a slight head or pressure by the tube f being regulated by a needle valve e, and admitted to the mixing chamber during the intake strokes in varying quantity, according to the opening of the throttle h, the resulting varying admission flow past the disc d thus causes this to be drawn downwards with a varying degree of opening. In another modification. the petrol is fed direct to the seat of the air valve, as shown in Fig. 5, thus the flow of petrol is stopped to a certain extent automatically should, by any chance, the motor come to a standstill with the petrol feed left on. But in order to obtain a perfectly constant mixture in con- itinuous working with any form of induction action car- '.burettor, it is essential that the level in the supply cistern should be maintained at one height. and to this end many methods have been devised and put to a practical test since the introduction of the automobile, many of which are shown below. Constant Level Cisterns.—The first attempt to mini- inise the effeet of variation in level of the fuel in tlie supply reservoir was made by the writer in 1885-87, in a •small two-cylinder petrol motor for an automobile, in •connection with an induction spray carburettor, as shown in Fig. 6, this consisting of a vena-contracta shaped air nozzle delivering into a mixing chamber c; in this the sprav feed was induced to flow from a tube t into an