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

PETROL CARBURETTORS. due to varying load and speed conditions and to opening. of the throttle li ; the proportion of air admitted accord- ing to the depression of the piston v was further co.rrectecl by forming the ports leading thereto, delta shaped. In the Xenia, by the use of a mercurial column, the depres- sion of the float d, carrying with it the supplementary air piston valve v (Fig. 24), is capable of an even more accurate movement, as in this case it is exactly pro- portionale to the difference of pressure in the mixing chamber x and of the out er atmosphere. In both the choke-tube 1c is proportioned for slow running, but not clead slow, as required in more modern car motors. Other compensating methods that have been used in single-jet carburettors arranged to operate on the air diluent principle may be mentioned—the vena-contracta choke-tube, first used in the Butler, the Decauville. and Excelsior carburettors. Of these the second-named is similar to the first. and in the last a floating ball is used; also in the carburettor known as the G. & A. this same methoel is adopted, but with a further refinement of action, by the aid of a nest of balis, which if all were of equal weight would act together, but are actually of different weights, and consequently lift in succession, according to the pressure depression in the mixing chamber; a modification of this method is also adopted in the Kingston carburettor. A great cleal, however, can be done with a properly proportioned and delicately sprung lift-valve if made of sufficiently large diameter, light and sensitive in action, for a motor not required to run at less than one-fourth its rat ed speed. Variable Jet Carburettors.—Previous to the more general adoption of variable jet carburettors having an