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

PETROL CARBURETTORS. 39 jet sprays direct into a choke-tube b, of slightly con- divergent form, arranged immediately under the 3-way drum throttle. As shown in the illustration, the throttle is in position for starting and running slow, and is closed to the main jet, all the air consequently is drawn up through the passage way b1, which acts as a choke-tube for the auxiliary jet s1. Now. on turning the regulator h over, from the slow position S, 45° or so, it will then be half open to the main tube b, and still be full open to the auxiliary spray inlet, as shown in dotted lines with the pointer at H ; but as a result of the motor speeding up to exceed a predetermined limit, there will follow a greater depression, and this will cause the ball v to lift, and thus automatically to put the auxiliary jet partly or wholly out of action ; again, with the throttle moved over to the full-open position as at F, the auxiliary jet is entirely cut out of action ; thus the modus operandi of this carburettor is partly due to variable pressure and partly to throttle controlled jet action. In the Stromber double-jet carburettor, the auxiliary jet is directly controlled by a large supplementary air valve ; the primary jet choke-tube in this instance can, therefore, be comparatively small, thus enabling the motor to be easily started and to run slow when throttled down. Perhaps the simplest and most compact triple- jet carburettor is the Huggins and Parker, better known as the H.P. ; in this, a drum throttle directly Controls and in succession, three spraying nozzles which are arranged at slightly increasing le vels, and in this manner the jet action is corrected to compensate for the high velocity flow resulting from speeding up with open throttle. In the Smith quadruple-jet carburettor, again.