US2441312A - Electrical induction heater for carburetors - Google Patents

Description

May 11,1948. W. N. DICKERSON ET! AL 2, 41,312

ELECTRICAL INDUCTION HEATER FOR CARBURETORS Filed April 5, 1946 Patented May 11, 1948 UN I TED.-

ELEcTBIGAL INDUCTION, HEATER FOR AB-' QBS.

WilliamN. Dickerson, Sullivan, 1116., and

Lucas-.D'. Gonzales, El Paso, Tex.

Application Aprilfi, 1946, Serial no. 659,694

1 Claim. 1.

This invention relates to an electrical induction heater for aircraft. carburetors, and more particularly to such a device for use in conjunction with pressureinjcctiontype. aircraft carburetors.

A primary object of this; invention is the provision of a device'adapted to prevent the forma tion of carburetor ice, andto-remove the same, in the event that such ice is formed;

An. additional object of the invention is the provisionof such a device whichwill minimize engine power loss caused bytheoperatio of the apparatus.

Still a further object of the invention is the provision of such a device adapted to heat the carburetor in such manner as substantially to eliminate any fire hazards which might be occasioned thereby.

A further object of the invention is the provision of such a device which may be readily applied to any conventional carburetor, and which will be effective under a wide variety of conditions and circumstances.

Still another object of the invention is the provision of such a device which will be sturdy and durable in construction, reliable and efficient in operation, and relatively simple and inexpensive to manufacture, assemble, and install.

Other objects reside in the combinations of elements, arrangements of parts, and features of construction, all as will be more fully pointed out hereinafter and disclosed in the accompanying drawing, wherein there is shown a preferred embodiment of this inventive concept.

In the drawings:

Figure 1 is a longitudinal sectional view taken substantially through the center line of a conventional carburetor for aircraft.

Figure 2 is a top plan view of a portion of the apparatus, certain parts thereof being omitted.

Figure 3 is a top plan view of an additional portion of the apparatus.

Similar reference characters refer to similar parts throughout the several views of the drawings.

As conducive to a clearer understanding of this invention, it may here be pointed out that heretofore methods of preventing carburetor ice have been developed, but the conventional anti-ice and de-ice methods are unsatisfactory. In alcohol anti-ice systems, it has frequently been observed that so much alcohol is lost by leakage as to render the device inoperative, and that such leakage provides a major fire hazard. Further, previously devised air heating systems are ineffective unless applied prior to entering an icing. area, and as only a skilled meteorologist can anticipate all icing conditions, such precaution has frequently not been taken. If-an air heating system is applied after'iceis indicated by loss. of power, the cylinder heat is seldom sufiicient to remove the ice. 7 r Y Experimentation has disclosed. that. in icing of the carburetor the entire air scoop does not freeze. This is-indi'cated by the fact. that the manifold pressure would drop' materially, and this has notwith repeated experiments been indicated. It follows-therefore, that since the engine supply of air remains adequate, failure is caused by the lack of fuel. Since the amount of fuel metered to the engine depends upon the volume of air rushing through the carburetor, it follows that engine failure is occasioned because the boost venturi and impact tubes are iced over. An important object of this invention is, therefore, the provision of a means to preclude the forma tion of ice in the boost venturi and the impact tubes, and thus preclude failure due to carburetor ice.

Having reference now to the drawings, there is generally indicated at In an air scoop of an aircraft carburetor, including a main venturi throat I I having positioned therein a plurality of radially positioned impact tubes I2, The tubes l2 communicate with an air chamber 13 positioned between the wall of the device and the venturi.

As is customary, the device includes a booster venturi l4 mounted on a suitable supporting bracket l5, and having an exteriorly positioned shoulder IS. A conventional butterfly valve 21 and control rod 28 therefor is also provided.

It may here be pointed out that in the customary operation of such device, air enters the boost venturi and simultaneously the impact tubes l2. The difference in pressure between the space l3 into which the impact tubes I 2 enter, and the pressure in the boost venturi I4 controls the movement of the poppet valve which controls in turn the amount of fuel released into the discharge pipe. The structure heretofore described has been conventional, and the instant invention comprises the positioning of a coilfof wire I! about the boost venturi l4, and an additional coil of wire l8 adjacent the inlet of the impact tubes. In the preferred embodiment of the invention, alternating current is applied from a conventional aircraft inverter of the 26 volt 400 cycle alternating type, to the coils I1 and I8, whereby to heat the metal venturi l l and the booster venturi M in a well known manner without heating the coils l1 and I8 themselves.

The temperatures to which the venturi l I and booster venturi H are heated is dependent upon the number of ampere turns of the coils l8 and I1, and, to some extent, upon the rate at which heat is lost by being extracted by air passing through the venturis. However, we have found that such heat loss is minor, and that a sufilciently high temperature may be maintained despite any variations in air temperature or moisture content of the air.

Cockpit control for the device may be readily provided by the use of a suitably positioned single throw switch and a warning light wired in parallel in a known manner.

, ing material; of separate high frequency induc- While in the foregoing the application of the device has been indicated in association with a carburetor of conventional type, it is to be noted that the carburetor may be wired as manufactured and equipp d with a suitable quick disconnection plug (not shown) for ease of maintenance. Obviously, the carburetor may be wound in a difierent manner from that herebefore disclosed in order to accommodate different types of carburetors.

From the foregoing it will now be seen that there is herein provided an improved apparatus, accomplishing all the objects of this invention, and others, including many advantages of great practical utility and commercial importance.

As various embodiments may be made of this inventive concept, and as various modifications tion coils concentrically disposed about both of said Venturi tubes for rapidly and inductively heating the same and said impact tubes to relatively high temperatures to prevent the formation of ice in said Venturi tubes and said impact tubes.

WILLIAM N. DICKERSON.

LUCAS D. GONZALES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 998,945 Avery et a1. July 25, 1911 1,096,989 Bentley May 19, 1914 1,577,276 Whitten Mar. 16, 1926 1,957,254 Eymann May 1, 1934 2,088,604 Littleiield Aug. 3, 1937

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