US1889304A - Carburetor of aircraft engines for insuring the regular engine working in inverted load conditions - Google Patents

Description

Nov. 29, 1932. T, zERBl 1,889,304

OARBUREI'OR OF AIRCRAFT ENGINES FOR INsURING THE REGULAR ENGINE WORKING IN INVERTED LOAD CONDITIONS Filed May 28, 1930 liatentecll Nov. 29, 1 932 TRANQUILLO ZERBI, F TURIN, ITALY, ASSIGNOR TO FIAT TURIN, ITALY PATENT oFElcE SOCIET ANONIMA, on

CARBURETOR OF AIRCRAFT ENGINES FOR INSURING THE REGULAR ENGINE WORKINGIN INVERTED LOAD CONDITIONS y Application led May 23, 1930, 'Serial No. 456,470, and in Italy November 29, 1929.

It is knownthat the carburetors now in use for aircraft engines insure a regular fuel supply to the engine even with strong inclinations of the Hying machine but wholly cease from feeding the engine when the load is inverted. This condition is attained in two cases, viz. in continuous inverted Hight and in sudden descents as under the action of airholes.

This invention concerns a carburetor which insures the regular running of the engine to which it is applied in the above lmentioned cases and the means for insuring this working is automatic and requires no operation by the pilot.

In order to insure ay regular feed in the carburetor according to thisinvention and in the two opposed conditions, the fue'l inlet conduit instead of opening directly into the constant chamber from which two separate conduits are branched, which open-into the constant level chamber. Of these two conduits one is alternativelv left in connection with said chamber and its outlet is adjusted by means retor in proximity to the chamber bottom and to arrange one or more auxiliary nozzles in proximity to the chamber top, these auxiliary nozzles coming into action only 'when the load is inverted and a set of nozzles being always at rest when the other set is working.

The accompanying drawing shows by way of example some constructional forms of the object of this invention; Figure 1 is a longitudinal section of y the carburetor. L

Figures 2 and 3 are sectional -views showing two further slightly modified constructions of the carburetor. j

Referring to Figure 1, the carburetor coinprises an annular chamber 1, in proximity vto in the suction level chamber extends into a'distri'buting of a suitable Hoat level adjusting device, while the bottom whereof extend two ordinary spray nozzles 2 and 3, respectively, for the minimum speed and for normal speed, which communicate with a channel 7 opening to the outside throughan air'intake 8 in orderto55 brake and mix the fuel Howing through said spray nozzles.

In the suction pipe 4; of the carburetor is arranged a throttle valve 6 and a large Venturi tube 5' within which is lodged a second 60 Venturi tube 5a provided with holes, to which the mixture Hows from the large spray nozzles through a conduit 3a. The fuel Howing from the small spray nozzle :'2 is conveyed through a conduit 2a and the holes 4a formed K pipe 4 into proximity to the throttle valve 6. l

In proximity to the top of the chamber 1 an auxiliary spray nozzle -ais arranged which normally communicates with an -air intake conduit -Pbopening to the outside in proximity to the bottom of the chamber. This spray nozzle -aopens through the conduit 3a into the inner .Venturi tube 5a of the carburetor.

The chamber 1 carries a Hoat 9 fast withal lever 11 articulated to a pivot 10 and provided with a needle 12 with conical ends. Two conduits 13 and 14 open opposite the conical needle ends into the space 1a formed in the chamber 1 and extend to a distributing chamber 15. The fuel from the carburetor Hows through a tube 16a into said cham- -ber and is filtered through a wire-gauze 1Gb.

In the distributing chamber a slide 17 is 5 mounted on a guide 18 projecting into the chamber 15 and is provided with conical ends for closing one or the other opening of the conduits 13 or 14 according as it sinks in one or the other direction under the action of its weight.

. through the oat 9 and needle 12 fast therewith which adjusts the outlet of said conduit 13. The large and the small spray nozzles 3 and 2 work in a normal manner, the fuel yis mixed with air before reaching the suction pipe 4, the justed intake 8.

When theflying machine flies in inverted load conditions, the working of the carburetor is niodied asfollows. The slide 17 is displaced on its guide and closes the opening of the conduits 13 and the fuel from the chamber 15 is conveyed through the conduit 14 to the chamber 1, the level in this chamair flowing through the ad- -ben being kept constant also in l'this case by the float 9, the needle 12 whereof worksby its opposite end. The spray nozzle a= then comes into action and` receivesbraking air through the conduit 'b-, while it conveys the air andy fuel mixture into the Venturi tube 5a. The spray nozzles 2 and 3 are then out of work.

Referring to Figure 2, it is apparent that the pivot 10a of the lever 11a fast with the float 9 is situated about in the middle position of this lever and this latter carries at one? end a head 11b fitted in a hollow 12b of the needle 12a. This needle is guided in its displacement by suitable projections 1b formed in the space la and works lalternatively for controlling the outlet of the conduits 12 and 13, respectively, extending from the `chamber 15. Owing to the inverted action of the constant level device mounted in the chamber 1 the slide 17 working y gravity `is replaced by a float 20 provi ed w1th 4conical ends 21 and 22 in order to close the opening of the conduits 13 and 14, respectively.

In case the flying machine flies in its normal position, on filling the chamber 15 'the float 2() remains practically always lifted,

thus closing the opening of the conduit 13 and the fuel flowing'through the opening 16 is conyeyed to the chamber 1 through the conduit 14,` the outlet whereof is controlled by the needle 12. It is apparent that duringinverted Hight by the displacement of the fioat 20 in an opposite direction the carburetor works further in the same manner y as described above.

Referring to Figure 3 showing aamodifcation of the construction shown in Fig. 2, the float 20 is replaced byv a-slide 17a withv coni-` ca l ends and in this case the arrangement of the channels 13a and 14a extending from the chamber 15 to the chamber 1 is inverted, while the working ofthe carburetoleremains unvaried.

What I claim is:

1. A carburetor for aircraft engines coniprising in combination with a constant level chamber, a distributing chamber connected with said constant level chamber through t`wo separate conduits, a float in said constant level chamber and means carried by said float for closing alternatively one end of said conduits and a slide in said distributing chamber for closing alternatively the other ends of said conduits.

2. Carburetor for aircraft engines comprising in combination with a constant level chamber, a cover for closing said constant level chamber,.a distributin'or chamber communicating with the fuel inlet, a conduit formed in the bottom of the constant level chamber connecting said distributing chamber with the constant level chamber, a conduit formed in the cover connecting said disv tributing chamber with. the upper portion of the constant level chamber, the inlet and outlet openings, respectively, of said conduits being in alignment, a slide in the distributing chamber having conical ends co-operatsaid conduits, a needle having conical ends carried by the float and co-operating alternatively with the outlet openings of said conduits.

-ing alternatively with the inlet openings of 3. Carburetor for aircraft engines com-

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