The Latest Solex Carburetter.
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One of the most successful applications of the duplex-jet system in carburetter design is certainly typified in the well-known Solex mdse. In an issue of this journal dated the 28th July, 1910, we were the firse to publish descriptive details of this particular construction
and this occasion we again afford sitmimlar distinction concerning the latest type of Solex on the market. It is manufactured by S. Wolf and Co., Ltd., 115, Southwark Street, London, SE,
The main principle—that is, the incorporating of two jets, one for slow running and another for use when the engine is working all out —is still retained, but there are one or two detail modifications emlimbed, based on practical experi, eece, which go to make this carburetter eminently suited for all (lasses of industrial machines.
We recently closely examined one of the new type, and, after going thoroughly into all details, are quite convinced that the latest model Solex will keep up its original good name. One outstanding alteration in the new -design is the lilting of a horizontal, instead of a vertical, choke-chamber ; the ports in the throttle valve am now machined to citable the main or auxiinute: jet to be brought into use quite iedependently of each other.
The standard practice of this maker, as is pretty well known, is ti dispense altogether with the toggle-joints in the float chamber, so that the simplicity of design in this section of the accessory is a feature. Inside the float chamber ie screwed the auxiliary jet, and this is surrounded by the float itself. The correct level of petrol is maintained by the action of the float coming in contact, as the chamber is filled, with a neat form of valve which is merely clamped in position when the carburetter is erected, this valve-housing, of course, being connected up to the mein petrol-supply pipe. Screwed over the auxiliary jet is a tube, provided with a ball valve, through which a sufficient. amonnt of air drawn to work in conjunction with the auxiliary jet, an orifice from this valve being in communication with the main throttle. A portion of this tube is also shouldered down to admit of the free passage of .air. The valve in the throttle chamber has been seem_ ally designed to give an even cutoff at all positions, so that there is no danger of the mixture, be it from the auxiliary or main jet, being locnlly restricted.
As before mentioned, the main and auxiliary jets are quite inde"mildew; one of the other, the theol Lie being so designed as to effect this. A feature to which we would call attention here is the mounting of the throttle-spindle on WI bearings. The main supply of petrol is conducted through a pe.s. sage leading from the base of the float-chamber, and screwed into a boss en a. projection of the base is a vertical tube provided with a cone-seating ; the main jet which is a loose fit in the before-mentioned tube, faces on this seat.
Immediately above the coned sent are drilled two small holes, leading to the main orifice. The relative diameters of the two holes to that of the bore of the jet-tube have been most carefully calculated. and are so proportioned that, when air is forced through the jet by atmospheric pressure, it automatically retards the flow of petrol in the central channel in direct proportion to the speed of the engine. This also obviates any tendency to depeession of gas in the choke-tube.
The jet an be very easily replaced, and should a user wish to change his present type of carburetter for one of the Solex make, the company sends out with the accessory four different sizes of jets. and it is merely necessary to try each one in turn quickly to find out which will give the maximum amount of efficiency so far as carburation is concerned. • A suitable covering screws over the main jet and communicates directly with the choke ring ; the size of the latter can also be varied to suit different conditions of working.
The Solex carburetter gives high efficiency on all types of engines, but this model is in particular suited to engines of the monobloc type. Another refinement which we noticed is the provision of a large knurled cap, which screws up to the choke chamber. This is so constructed as to prevent the waste of petrol due to an occasional 'blow-back" in the induction system, due perhaps to defective tuning, as when such an interruption in the induction occurs, i there s often a considerable amount of petrol wasted, and the Solex people claim that this lates1 provision saves as much as 7 to It per cent. on the fuel bill, as th( petrol is trapped and withdrawi again into the main system.
The whole of the c.arburetter cat immediately be taken to pieces foi cleaning purposes by merely an screwing one partthat is, tin hexagon-headed ball-valve housim which covers the auxiliary jet, OA position of which can clearly be see: in the above illustration.
One of the principal advantage which the makees 'laim is the bris: pick-up which this form of earburei ter ensures, this being attained le the fact that there is always certain surplus of fuel retaine around the main jet, and immed
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ately the auxiliary et has bee. closed, this reserve of petrol quickly taken up, so that there : no delay in the main supply comm into use.
Uniform air acceleration is a fet ture which has been associated wit the Solex carburetters since the first inception. This is a great fact( in the matter of silence. On sole 130 we include a photograph of dismantled Solex.