Apparatus For Promoting Complete Combustion

Abstract

Apparatus for insuring that combustion within a combustion chamber of an apparatus such as a heater, boiler, furnace, and the like, includes arranging the fuel, air and ignition means in a combustion chamber such that combustion takes place in the vicinity of a heat-conducting and heat-equalizing device in order to insure an even temperature zone at the combustion space and to minimize the danger of carbonizing or coking. The heat-conducting and heat-equalizing device comprises preferably a hollow body made of a material providing good heat conduction and heat-equalizing characteristics, such as a mass of a metal material having a capillary action on liquid contacted thereby. The hollow body is advantageously filled with a liquid such as sodium and the material of the metal body, for example, a spun copper or a braid metal material is such that by capillary action the heat is distributed by the liquid uniformly over the entire surface of the body. The heat-conducting and heat-equalizing body is arranged directly in a space where the major portion of the combustion is to take place.

Description

SUMMARY OF THE INVENTION

This invention relates in general to apparatus for improving combustion, and in particular, to a new and useful device such as a heater, or the like, having a combustion chamber with means for admitting fuel and air into a combustion space for combustion in the vicinity of a body of a highly conductive heat-equalizing material to promote a heat-equalizing zone of substantially constant temperature within the combustion chamber.

The present invention is particularly concerned with the provision of a combustion chamber having a heat-equalizing means therein arranged to lessen the tendency toward coking or carbonizing of the fuel during the combustion process with a view to obtaining preferably a blue combustion, that is, a combustion of the fuel which, will proceed to the extent that there will be very little or any residue remaining upon the completion of the combustion.

It is known that coking will occur in combustion chamber devices utilizing pressure atomization burners, or similar fuel injection devices, for example, in space heaters for automobiles, that a coking will occur due to poor or irregular combustion. During the mixing of the injected fuel and the combustion and upon combustion and ejection of the hot combustion gases, different temperatures occur in the combustion chamber particularly at the walls thereof. Because of these differences of temperature there is always a temperature at which some portion of the fuel mixture will not burn completely but will deposit as a coking product on the walls. Such deposition products, as for example hard asphalt will deposit at various locations on the combustion apparatus and hence the progress of the combustion will be considerably disturbed. This disturbed combustion will also cause smoke emission, or smoldering, in the combustion chamber and this will contribute to pollution of the air. This has particular disadvantages, for example in respect to space heating systems in motor vehicles. Of course, when these systems are badly coked or carbonized, they will require servicing to remove the depositions for example, by scrapping. The time required for such scrapping is balanced by the fact that the overall efficiency of the combustion chamber will decrease to an extent that it cannot be operated any longer.

A primary cause for the coking or carbonizing is the differences of temperature which exist along the length of a combustion chamber and therefore attempts have been made to achieve an improvement of the condition by the use of suitable inserts. It has been tried for example, to bring about an improvement by the installation of copper conducting elements but the copper has so low an oxidation temperature that these inserts burn up in a short time. Other materials which seem suitable were either too expensive or their conductivity is too low.

In accordance with the present invention, a combustion chamber having a means for supplying combustion air and fuel into a zone in which the fuel and air is to be ignited, and which may include, for example, means for deflecting and guiding the flame produced, there is provided an arrangement by which coking is prevented and blue combustion of the liquid fuel is achieved. To achieve this a heat tube is arranged in the region of the fuel mixture processing zone and the combustion zone or combustion space. Such a heat tube comprises a heat-conducting and heat-equalizing mass which is preferably in the form of a tube comprising a metallic hollow body made of a material having a mass capillary action on liquid and good conductivity, for example, spun copper or a braid material. The interior of the body is filled with at least a small quantity of a liquid such as a liquid sodium. This liquid evaporates upon being heated, and by the capillary action of the material forming the hollow body and distributes the heat uniformly over the entire surface of the heat tube so that the temperature gradient throughout the burning space and the combustion chamber is substantially zero. By the arrangement of the heat mass or heat tube in accordance with the invention the combustion chamber space can be maintained at a substantially uniform temperature along its entire extent so that there will be little or no likelihood of undesired coking or carbonizing taking place. The construction is such that there will usually occur a sudden heat jump in the combustion chamber of from 50.degree.to 700.degree. C. from the air supply and fuel mixture supply conduits. This heat jump will depend on the design of the entire combustion chamber arrangement, however. By employing a heat tube made of a spun copper mass having a capillary action on the liquid, it is possible to achieve substantially 10,000 times the thermal conductivity of ordinary copper.

In accordance with the embodiment of the invention the heat mass is designed as a heat tube in the form of a ring or space cylinder. This cylinder advantageously includes, on the heat admission side, means for increasing the heat transfer area such as extensions or ribs. The apparatus may be incorporated in a space heating burner for example wherein the tube has an opening to accommodate a spark plug for providing central ignition to a fuel and air mixture which is admitted axially. In one form the invention may be incorporated in a resonant burner in which the heat tube is located adjacent the supply conduits for air and fuel in back of the means for igniting the mixture.

In another embodiment the heat-conducting and heat-equalizing mass is maintained in a central location, for example on a pot burner in which it will extend axially upwardly therefrom in the direction of flame propagation.

Accordingly, it is an object of the invention to provide an improved combustion device which includes a mass of material having good heat conducting and heat equalizing capabilities which is arranged in the vicinity of the combustion space and provides a means for maintaining a uniform temperature in this space in order to promote complete combustion of the fuel.

A further object of the invention is to provide a combustion chamber which includes a tube of a material such as a spun copper or braid having a capillary action characteristic and which includes a cavity which is filled with a liquid such as sodium which is adapted to be moved by the capillary action of the material forming the mass in order to provide a temperature equalization throughout the length of the mass in the combustion chamber.

A further object of the invention is to provide a device such as a pot burner which includes a mass of a material in the pot adapted to contact the fuel therein and extending upwardly in the direction of flame propagation and providing a heat-conducting and heat-equalizing mass for insuring a uniform temperature in the combustion zone of the burner.

A further object of the invention is to provide the combustion device having means for maintaining a combustion zone or temperature equalization and which is simple in design, rugged in construction, and economical to manufacture.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the Drawings:

FIG. 1 is a partial axial sectional view of an automobile space heater having a combustion chamber constructed in accordance with the invention;

FIG. 2 is a view similar to FIG. 1 of a resonant burner;

FIG. 3 is a view similar to FIG. 1 of a household pot burner for home heating units; and

FIG. 4 is a view similar to FIG. 1 of an atomizing burner for a boiler or similar device.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in particular, the invention embodied therein in FIG. 1 comprises an automobile space heater generally designated 50 which includes a housing 52 defining a combustion chamber 1 having a radial extension 54 defining a chamber 4 for a spark plug 6. Fuel is admitted through a conduit 5 into the antechamber 4 for combustion in the combustion chamber or space 1. Combustion air is admitted through a central tubular member 7 to the combustion chamber zone defined within the chamber 1. Discharge of the heated high-temperature gases is through a flame nozzle section 8 of the housing 52.

In accordance with the invention the combustion space 1 is provided with a heat-conducting and heat-equalizing device in the form of a hollow tube 2 made of a metallic material such as spun copper or braid. The material of the tube 2 is advantageously such that it effects a capillary action on liquid in contact therewith. It is effective to draw a liquid such as liquid sodium 56, which is partially filled into the interior thereof, throughout the length of the tube in order to provide a temperature equalization zone within the combustion chamber 1. The tubular mass 2 therefore provides a means for distributing the heat uniformly over the entire surface of the tube in the combustion chamber space 1 to insure that there is no area of temperature variation in this space which would prevent the good burning of the fuel admitted thereto. The distribution of the sodium throughout the mass of the tube 2 by capillary action is such that the temperature gradient may be reduced to substantially zero. In the embodiment of FIG. 1, the tube 2 is provided with an opening 2a to permit access of the spark plug 6.

In the embodiment indicated in FIG. 2, there is provided a resonant or oscillating burner generally designated 58 which includes an axially elongated combustion zone or space 9 and is provided with an ignition antechamber for a spark plug 6'. In this construction a temperature equalizing mass 2' in the form of a tubular member is positioned in the principal combustion zone 11 adjacent to and to the rear of the spark plug 6'. The tubular mass 2' is arranged directly adjacent and in heat conduction with a flame tube 10. Combustion air is supplied through a combustion inlet connection 12 and fuel is supplied through a nozzle 13, into the combustion space 11.

In the embodiment indicated in FIG. 3, there is shown a burner of a type which may be employed in a boiler or similar heating apparatus and which includes a burner pot 14 having an evaporator disc 15 spaced from the bottom wall of the pot and which is supplied with a fuel through an inlet 13. The required combustion air is directed in through an inlet 16 which is directed through a perforated air supply pot ring 17. A flame ring 18 is mounted on one end of the combustion air supply ring 17 and it carries a flame holder 19. In accordance with the feature of this embodiment a heat-conducting and heat-equalizing mass 20 in the form of a tube 20 is arranged in conductive connection between the flame holder 19 and the fuel-evaporating disc 15. A plurality of extending ribs 21 provide increased conductive surfaces for the tube 20. The tube 20 may advantageously be filled with a liquid sodium 60 for example as in the embodiment of FIG. 1.

In the embodiment shown in FIG. 4, there is shown a conventional boiler furnace portion 62 having a flue 22. An atomizer burner 23 is positioned in a wall of the boiler and extends into the furnace chamber. The atomizer burner 23 includes a central fuel delivery conduit 26 terminating in an atomizer nozzle 24 which directs the fuel in the form of a spray 64 into the combustion zone. An air diffuser piece or air nozzle 27 is arranged at one end of the atomizer burning housing assembly for aiding in the directing of the air into association with the fuel spray 64. Combustion air flows through the atomizer burner housing 23 to the combustion space at the interior of the furnace 62. In this embodiment a heat ring tube 2" is arranged directly adjacent the burner nozzle assembly and it is made of a mass providing a good heat conduction and good heat equalization throughout an axial length in the furnace 62 corresponding to the combustion length.

Claims

I claim:

1. A combustion device comprising wall means defining a combustion chamber, means for directing fuel and combustion air into said combustion chamber and for igniting the fuel and combustion air therein to provide combustion proceeding along a combustion zone, and a heat conductive mass arranged in the combustion zone and being of a material to provide a temperature equalization throughout said combustion zone, said heat conductive mass comprising a hollow metallic mass having at least the interior thereof of a material having a capillary action, and a liquid in said mass capable of evaporating when subjected to heat to be drawn by capillary action throughout the length of said mass to equalize the temperature thereof.

2. A combustion device, as set forth in claim 1, wherein said liquid in said mass being a liquid sodium.

3. A combustion device, as set forth in claim 1, wherein said wall means comprises an axial discharge for the combustion flame, an axial inlet opposite to said discharge for combustion air, an antechamber having a spark plug therein, means for admitting a liquid fuel into said antechamber, said antechamber being connected to said combustion chamber for mixing the fuel with the combustion air being moved therethrough and for ignition of the mixture by said spark plug, said hollow metallic mass comprising a hollow ring of a conductive metallic material, and said ring having an opening therethrough for communicating said antechamber to said combustion chamber.