US2396868A - Liquid fuel combustion apparatus - Google Patents

Description

March E99 @46 H. `LDE N. MCCOLLUM 2,395,858

LIQUID FUEL COMBUSTION APPARATUS Filed sept. 8, 1941 is formed in a Patented Mar. 19, 1946 2,396,868 LIQUID FUEL COMBUSTION APPARATUS Henry J. De McCollum McCollum, deceased N. McCollum executrix Chicago, Ill.; Thelma Isaid Henry J. De N.

Application September 8,1941, Serial N0. 410,039

4 Claims.

rapid and complete combustion.

ther objects will appear from the following description, reference being had to the accomv panying drawing, in which:

a central vertical sectionalview of` a chamber for the burning of a liquid mixture;

and 3 are transverse sectional views the lines 2 2 and 3 3, respectively,

en 1 is combustion fuel and air Figs. 2 taken on of Fig. 1.

As shown in Fig. 1, a combustion chamber I I2 8, the inner end of which projects a substantial distance into the combustion chamber Hle The induction tube is provided with a plurality of radial ports 20, which may be formed as ber lll so that it travels upwardly through this chamber in generally helical paths. This facilitates complete combustion of the mixture, especially at high fuel feed rates.

The fuel mixture is adapted to be ignited by an electrical resistance wire igniter 2S suitably secured in an igniter housing 28, the igniter and of the construction housing being preferably more fully disclosed and claimed in my prior Patent No. 2,191,178.

The products of chromium alloy, such as Nichrome-V or "Inconel, which are highly resistant to deterioration by the high temperatures involved and by the gases of combustion which are present in the combustion chamber. 'I'he spirally coiled of this spiral sheet-like pocket l2 faces in a direction opposite to that in which the fuel mixture ows (as indicated by the arrows) so that the pocket, thus causing re-ignition of the mixture within the combustion chamber I 0.

re-igniter which is at the highest temperature.l l

The spirally coiled sheet 40 admirably fulfillsv these conditions, since but a small portion of the heat contained therein upon accidental interruption of combustion is conducted from its outer coil to the induction tube 16. Only the outer surface of the outer coil of the re-igniter is partially cooled by radiation and by the iiow of the combustible mixture past it. The inner coils of the re-lgniter are thus enabled to retain their heat for a long period of time, and the combustible mixture can reach the inner coils through the spiral sheet-shaped pocket 42.

Since the re-igniter is made of a corrosionresistant metal alloy, there is no danger of fragments of the re-igniter being carried from the heater with the exhaust gases. It will be understood that in many installations on airplanes the fuel mixture is supplied from the airplane engine supercharger at a point at which the pressure is relatively high, and the products of combustion from the heater are returned to the supercharger at a point at which the pressure is relatively low. Thus, if the re-igniter were of a type which might break or disintegrate, much damage might be done in the airplane engine by fragments of the re-igniter. It is for this reason that the re-ignition means herein disclosed is preferred over the re-ignition means shown in my aforesaid prior application whenever the heater exhaust is returned to the engine supercharger.

1t will be understood that the heater assembly is entirely enclosed so that, neither the combustible mixture noi the products of combustion can be diluted by or escape to the atmosphere. Furthermore, the difference in pressure between the induction tube I6 through which the combustible mixture is supplied and the exhaust of the heater is relatively great, so that the now of the mixture through the combustion chamber is at high speed. By having the ow through the heater at very high speed, and supplying elicient heat exchange apparatus, the size and weight of the heater may be reduced to a minimum, making the heater very practical for use on aircraft. However, the fact that ilow through the heater is at such high speed greatly increases the problem of re-ignition. I have found, however, that the re-igniter disclosed herein functions satisfactorily under the most adverse conditions of operation.

While I have shown and described a particular embodiment of my invention, it will be understood by those skilled in the art that the objects of the invention may be attained by the use of constructions differing in shape and form from that disclosed without departing from the underlying principles of the invention. I therefore desire, by the following claims, to include within the scope of my invention all such variations and modifications by which substantially the results of my invention may be obtained through the use of substantially the same or equivalent means.

I claim:

l. In a heater for burning a fuel and air mixture, and having a combustion chamber. a reigniter for causing re-ignition of the flame in the V combustion chamber should it become accidentally extinguished, comprising a spirally coiled sheet of a heat and corrosion resistant metal alloy, with adjacent coils of the sheet separated to provide a spiral sheet-like pocket of greater width than thickness.

2. In a heater, the combination of means providing a combustion chamber, an induction tube for said heater projecting into said combustion chamber and having radial openings therein, means on said induction tube adjacent said openings for causing fuel mixture flowing from said induction tube into said combustion chamber to .follow a generally helical path through the combustion chamber, and a heat and corrosion resistant metal alloy re-igniter secured to the end of said induction tube and providing a pocket for the reception of the fuel mixture, said pocket having an opening facing in a direction opposed to the direction of helical flow of the fuel mixture.

3. A re-igniter for use in the combustion chamber of a heater for re-igniting the combustible mixture therein should the flame become accidentally extinguished comprising, a spirally coiled rigid sheet of a heat and corrosion resistant metal alloy including a plurality of turns spaced from one another to provide a spiral sheet-like passageway between the turns, the outer end of said passageway adapted to face in a direction opposite the general direction of flow of the combustible mixture through the combustion chamber.

4. A re-igniter for use in a combustion chamber burning a combustible mixture of fuel and air comprising, a rigid sheet metal structure supported at one end and providing a plurality of f portions one within the other with the space between said portions forming a passageway of thickness less than one-tenth of its width and opening into the combustion chamber at one end and at one side of said structure.

HENRY J. DE N. MCCOLLUM.

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