US1791318A - Carburetor - Google Patents

Description

Patented'Feb. 3, 1931 UNITED vSTATES usine PATE oFi-i THEODORE C. MENGES, OF WATERLOO, IOWA, ASSIGNOR TO ASSOCIATED MANUFAC- TURERS COMPANY, OF-WAT`ERLOO, IOWA CARBURETOR Application led. May 9, 1928. Serial No. 276,401.

My invention relates to improvements in carburetors, and the objects of my improvements are these: first, to furnish a simple, inexpensive and effective carburetor which o while primarily designed for two cycle internalcoinbustion enfrines, yet is equally useful for engines having other pluralities of cycles; second, to supply for the carburetor a fuel intake device having a check valve for preventing a return at times of fuel thereabove, said check valve also functioning in case of back firing of the engine in preventing ignitionof the contents of the fuel tank; third, to provide the carburetor with communicating i fuel receiving and air intake chambers, the latter having an adjustable shutter whose `maximum areal opening is much greater than the area of the carburetor delivery port for mixed fuel and air, whereby flooding may be quickly prevented, and the combined chai-..-

bers being adapted to retain a small residue .of unused fuel after supply and engine draft, to permit quick pick up of fuel when the engine is running under alight load, or when running idle; fourth, to sol associate a needle valve with the fuelintake of the carburetor in connection with the special construction of the fuel receivingl chamber of the latter,

that fuel is delivered directly into said chain- .30 ber without possibility of a leakage past the remote mounting of the needle valve, land fifth, to supply a resiliently controlled valve for the passage from the mixing chamber to the delivery port of the carburetor, to prevent compressed fuel gas from returning from such gas under compression in Vthe crank-case of an engine with which the carburetor is iii-communication in certain types of engines.

All the above objects have been successfully accomplished in the device of my invention exemplified herein in the drawings, and in the appended description and claims. In said drawings, both of the figures are taken on a somewhat magnified scale for the sake of clearness, but the device may be furnished in any desired scale, and modifications thereof in any particular are nevertheless l covered by the principles ofiny invention and if) the scope of the claims.

In the drawings, Fig. 1 is a Vertical loni gitudinal section of the carburetor 4taken along the axis of the needle valve thereof, with a part' of the fuel supply pipe broken away, and Fig.l 2 is al top plan of the car! buret-or.

The body l of the carburetor has at the bottom a mixing chamber 2 from which arises a diminished passage 20 leading into a mixed fuel delivery chamber 2l thereabove 55,

having in its side wal-l a lateral delivery passage and port 22 traversing the vertically elongated flat bracket body 4. This bracket body-may have at top and bottom apertures 5 to receive headed screws or other securing"y means for mountingthe carburetor uponan engine crank-case with the port 22 in communication with the interior of the crankcase, when the engine is `of the two cycle type where lthe fuel gas and air mixed therewith arecompressed-initially in the crankcase by piston action and before delivery of the fuel through the usual by-pass port at times into the combustion chamber of the engine. vThe carburetor-may, however, obv

cycles.

The carburetor body includes integrally the bowl or cup-shaped communicating part 3, the partially concave botton 2 of the part 3 becoming flatly horizontally continuous with the flat bottom of the chamber 2, whereby in effect the cavity becomes a single elongated chamber. cup part 3 has segmental openings around a central pint'le 3l upon which is rockingly mounted a shutter 32 elongated outwardly to provide a handle, and which has also segmental openings 35 which may varyingly register with or communicate with said openings in the cover 36 according to an adjustment desired.

The mixing chamber 2' is supplied with fuel gases as follows. In a lateral bulge 6 of the carburetor body 1 is a closed top downwardly opening passage 7 interiorly threaded in its lower portion to seat the upper eX- teriorly threaded end of a supply pipe 9. A

The top cover 36 of the Y narrower horizontal passage 8 leads from the passage l into the chamber 2 by way of the diminished passage 2O above the latter.

At the bottom of the vertical si oply pipe 9 l position therearound al tubular valveehamber 10 having a medial partition 12 with central aperture-d valve-seat 13 upon which normally rests a ball check-valve 14:. Between the partition 12 and the imperforate bottom part 11 is a. chamber whose side walls have receiving openings separated by standards 15, said openings being circumferentially inclosed by finely meshes screen material 16, and the valve-chamber 10 is immersedin the liquid fuel of a tank not shown.

rlhe delivery end of the passage 8 is controlled by a needle-valve 18 which traverses the passage 2O over the mixing chamber 2 and is threaded to be seated adjustingly in an interiorly threaded horizontal bore '17 leading oppositely through an elongated cylindricfl portion of the body 1 to project outwardly therefrom, said needle-valve having an end notch to permit adjustments, and having a locking wing-nut' 19 mounted on its threaded stem.

lt should be particularly observed that the mixing chamber 2, the intermediate fuelreceiving passage 20, and trie valve-chamber 21 are located in relative superposition for an object' to be disclosed.

The valve-chamber 21 contains a valvehead 28 whose upwardly directed stem 2l' is loosely seated in a cavity 28 positioned axial ly in a headed screw closure 25 above. rlhe upper hollow part 33 of the carburetor body 1 isV cylindrical and contains at the top an int rior thread 23 to receive the threaded diminished part 2d of the kclosure 25. rThe latter has a diminished cylindrical and depending part 29 around the stem 27 to seat a light helical lcompression spring 30 which is engaged between the lower face of the partl 24. and the flat upper face of he valve-head 28. 'l-his spring normally keeps the valve 28 closed.y ln the drawing, 1 shows the valve in its uppermost position as at the close of a fuel draft outwardly to the engine by way of the port 22. f

Operation-Ilmo screen 18 prevents small solid impurities fromv passing into the hollowv of the valve-chamber 10, but allows free entry of the liquid fuel. The ball checkva-lve lifts when suction from the engine acts thereupon to let fuel pass into lthe tube 9, and passages ,7 and 8. The needle valve 18 being opened, the fuel enters the space 20.

lt will be well to mention here that small power-unit two-cycle gas engines are frequently employed in households for actua-ting washing machines and other driven applianees, and when these or other cycle engines are used it is very requisite that there be no leakage of liquid fuel, as readily occurs around the stem of a needle-valve as ordinarily mounted in the carburetor. ln my carburetor such leakage cannot take place, because l have caused the fuel to be delivered from the passage 8 past the needle point directly into the wide passage 2O to drop thence downwardly into the wider mixing chamber 2. ils the latter is below the receiving space 20 and wholly below the seat 17 of the needlevalve 18, it is impossible that liquid fuel can enter the seat 17 and leak outwardly therefrom.

Furthermore, in the action of the engine, as the valve 28 is alternately lifted and dropped, the engine or crank-case thereof cannot become flooded from the contents of the chamber 2 at times. This is owing to the fact that l have supplied air-ports for the air receiving cup 3 whose combined ai' as under normal delivery of air are in 'heir aggregate much larger than the cross ectional area of the carburetor delivery A ort 22. ln the event that but a small air volume is being delivered into the cup 3 because of the restrictive action of the shutter 32, and symptoms of flooding occur, the operat r may quickly rock the shutter to effect wider'opening of the air ports so that the larger volume of entering air will prevent the flooding. l

As the bottomv of the chambers 2 and 2 is flat and horizontally continuous, any surplus of liquid fuel that may remain there is picked up by a succeeding suction. This is beneficial where an engine is running under a light load, because the charge of fuel gas in the mixture will be richer after picking up this surplus.

W hen a back-firing occurs in the crankcase, the ball check-valve 14 is closed, so there is no possibility of fire communicating to the contents of the fuel tank.

Having described my invention, what I claim as new, and desire to secure by Letters lPatent, is:

1. A carburetor containing a mixingchamber with imperforate bottom and sides and Ahaving a controllable air-port-in its top, said carburetor having a valve-chamber in communication with the top of said mixingchamber and having a delivery-port, a resiliently controlled valve controlling said valve-chamber inlet, saidcarburetor having a fuel nozzle delivering into the upper part of the miXing-chamber adjacent to the valveseat of the resiliently controlled valve, a conduit leading into said carburetor to said nozzle, a valve-chamber in the outer end of said conduit in communication with a supply of liquid fuel, and said valve-chamber having a valve-seat and a check-valve for normally closing the valve-seat from above to prevent return of fuel and also to prevent ignition of the fuel below the valve-seat due to back-firing of the engine.

CFL

2. A carburetor containing a, mixingohamber with imperforate bottom and having an air-port in its top, said carburetor having a valve-chamber in communication with the top o said mixing-chamber and having a delivery-port, valvular means oontrolling said delivery-port, said carburetor having a fuel nozzle delivering horizontally into the upper part of the mixing-chamber adjacent to the valve-seat of said` valvechalnber, said carburetor having a horizontal interiorly threaded opening across the upper part of the mixing-chamber and alined with said nozzle, and a threaded needle-valve stem seated adjustably in said opening to cross the mixing-chamber and having a conical termination to enter and control the delivery of said nozzle, whereby liquid fuel delivered upon said conical termination en- ,f ters the mixing-chamber at the top in a conical spray and Wholly above the fuel supply in the lovver part of the mixing-chamber.

In testimony whereof I aiix my signature.

Y THEODORE C. MENGES.

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