GB2104641A - Method and apparatus for feeding fuel into an oxidizing atmosphere during its combustion - Google Patents

Abstract

Fuel is fed through pipes (2) and nozzles (3) into an oxidizing atmosphere (b) after impinging on hard surfaces (5) and, on their impingement upon the latter, are formed into thin films (c) flowing surface into the oxidant (b) in order to interact therewith. After impingement upon the hard surface (5), the fuel films (c) are heated. The invention is readily adaptable to application in heat power engineering, chemical, petrochemical, gas and metallurgical industries, as well as in the industry of constructional materials, with the possibility of using both liquid and gaseous fuels. <IMAGE>

Description

SPECIFICATION Method and apparatus for feeding fuel into an oxidizing atmosphere during its combustion The present invention relates to heat engineering, and more particuiarly, to a method and apparatus for feeding fuel into an oxidizing atmosphere during its combustion.

The invention is readily adaptable for application in heat power engineering, chemical, petrochemical, gas and metallurgical industries, as well as in the industry of constructional materials, with the possibility of using both liquid and gaseous fuels.

There is known a variety of methods and devices for feeding fuel into an oxidizing atmosphere during its combustion.

One of the most frequently used is a method of feeding fuel into an oxidizing atmosphere and an apparatus for effecting same, according to which an atomized fuel is injected under pressure into a stationary oxidizing atmosphere (see a book by Yu. F. Ditiakin et al., entitled "Atomization of Liquids", published in 1977, pp. 17-100).

However, the above method and apparatus fail to ensure good atomization of viscous fluids due to power losses of fluid caused by friction.

There is also known a method of atomizing fuel in an oxidizing atmosphere and an apparatus for effecting same, in which additional energy is imparted to atomized fuel in order to increase its speed so as to be broken up into droplets by a flow of gas. (Cf. Germany, Federal Republic of, Pat. No. 912,732, cI. 24B, 8/01, issued in 1954).

However, the above method and apparatus are ineffective in that they require substantial consumption of compressed gas to be fed under high pressure for atomization of fuel.

In practice, when liquid and gaseous fuels are fed into an oxidizing atmosphere in the form of jets or sprays, their speed is greater than that of the flow of oxidant.

For example, there is known a method and an apparatus for multi-jet feeding of fuel into a drifting flow of oxidant (see a book by V. A.

Speisher, entitled "Gas Combustion at Electric Power Stations and in Industry", Energia Publishers, Moscow, 1967, p. 1 76).

According to this method and apparatus, the sizes and mutual arrangement of jets or sprays of fuel are selected so as to be substantially uniformly distributed over the cross section of the drifting flow of oxidant, a task not always possible to fulfill. Therefore, one of the primary conditions for adequate intermixing of fuel and oxidant and, consequently, for its complete combustion is uniform distribution of the fuel jets or sprays in the oxidant.

It should also be noted that adequate fuel and oxidant mixing requires more than 95 per cent of the travelling path and residence time of the oxidant and fuel particles in a furnace enclosure, which necessitates large operating dimensions of fuel burning devices, since rapid and adequate fuel and oxidant intermixing cannot be achieved within a short path of its travel.

One of the most frequently used methods of feeding fuel into an oxidizing atmosphere comprises complete premixing of fuel and oxidant, wherein the flow of fuel is fed at a right angle to the flow of oxidant, with their subsequent rotation in a swirler. (Cf. USSR Inventor's Certificate No. 256,930,A 21 d, published in 1969).

However, the mixing of fuel with an oxidant (for example, air) is possible only by use of cold oxidant in order to avoid ignition of the gas-air mixture within the body of an apparatus.

Furthermore, a decrease in the consumption of fuel and oxidant, as well as in the velocity of the gasair mixture flow, may cause overshooting of flame at the nozzle orifice. If the flow rate of air is below a permissible level, the length of flame will increase and the flame temperature will fall, which may cause breaking away of flame from the apparatus nozzle.

Another known method of feeding fuel into an oxidizing atmosphere during its combustion consists in that the fuel being fed is formed into jets and then caused to interact with an oxidant.

This method is performed with the aid of an apparatus described in USSR Inventor's Certificate No. 241,353.

The above method and apparatus permit fuel to be mixed with a flow of hot air.

The appratus of the Inventor's Certificate referred to above is basically a burner which comprises an air chamber with fuel inlet pipes formed with outlet nozzles for producing fuel jets.

The burner in question is well adapted to a hot air-blowing operation at optimum air flow rate coefficient. With the use of a cold air-blowing technique and at a low air flow rate coefficient, the burner fails to ensure combustion of gas in a flame of stable length and high temperature.

Combustion of fuel in a short-length flame can be achieved only when the diameter of the nozzle orficie does not exceed 40 mm, and the diameter of the fuel inlet pipe is such that the annular free air passage between the nozzle walls and this pipe will be equal to or less than 9 mm, with the diameter of fuel discharging holes in the pipe being 2.5 mm. In addition, since the velocity of hot-air flow should not exceed 8 m/sec in the device nozzle, which is due to specific conditions of gas dynamics, the production efficiency of such a burner will be low. In a high-temperature combustion of a great amount of gas mixed with hot air, a heat plant should be equipped with a considerable number of burners, in which the distance between the centre-line of the nozzles should exceed by 2-3 times the diameter of the air outlet nozzle.This, in turn, complicates the burner construction, renders the burner refractory repair operation time and labour consuming, and leads to a higher consumption of refractory materials for the construction of tunnels.

What is required is a method and an apparatus for feeding a fuel into an oxidizing atmosphere during fuel combustion, which will permit adequate intermixing of fuel and oxidant to occur within a short path and the combustion of fuel to be effected in a short-length high-temperature flame at minimum power inputs and enhanced combustion efficiency, while ensuring structural simplicity and operating reliability of the apparatus.

The invention provides a method of feeding a fuel into an oxidizing atmosphere during its combustion, which comprises producing jets (a) of fuel and causing the latter to interact with an oxidant, wherein, prior to interaction with the oxidant (b), the fuel jets (a) are projected against a hard surface and, on their impingement thereupon, are formed into thin films (c) which flow off the hard surface into the oxidant (b) thereby to interact therewith.

In this way it becomes possible to ensure effective combustion of both liquid and gaseous fuels, and to raise the temperature within the volume of combustion products by stepping up the rate of the fuel and oxidant intermixing and by enhancing the process of ignition of the combustible mixture.

On impingement upon the hard surface, the fuel films (c) are preferably heated for the purpose of accelerating the process of fuel ignition in the oxidant (b).

The fuel films (c) are preferably heated to a fuel dissociation temperature and above it, so as to permit the process of dissociation, which normally proceeds in the burning flame, to initiate prior to mixing of fuel with the oxidant (b). The fuel films (c) are rapidly heated to permit vigorous dissociation to proceed therein, and the fuel is introduced into the oxidant (b) in the form of films (c) with products of dissociation contained therein. As a result, the process of fuel ignition in the oxidant (b) is stepped up, the length of flame is shortened, and the process of fuel combustion is stabilized irrespective of the amount of fuel and oxidant being consumed. In addition, the possibility of flame breaking-away or overshooting is ruled out and a noiseless process of fuel combustion occurs.

The heating of the fuel films (c) may be achieved by means of heat transfer from the burning fuel through a hard surface which is heated in the course of fuel combustion and then gives up a part of its heat for heating the fuel films in question.

Also, the fuel films (c) could be heated by passing electric current through a hard surface.

Hence, there is no need for a device for igniting the combustible mixture since this procedure will be performed by the electrically heated hard surface. By altering the parameters of electric current passing through the hard surface, it becomes feasible to vary the temperature of its heating and, consequently, the temperature of the fuel films (c) heated thereon. This, in turn, makes it possible to control the rate of fuel dissociation, the length of flame and its temperature, as well as the flame luminosity.

The invention also provides an apparjtus for feeding a fuel into an oxidizing atmosphere during its combustion, comprising a chamber intended to receive an oxidant (b) therein and having fuel inlet pipes formed with outlet nozzles for producing fuel jets (a), wherein, according to the invention, in opposite spaced relationship with the outlet nozzles of the fuel inlet pipes there is provided at least one deflector with a rigid surface used to form thin films (c) from fuel jets.

The deflector and the outlet nozzle of the fuel inlet pipe are preferably arranged relative to one another so as to permit the angle (p) of jet incidence to be more than or equal to 900 but less than 1800.

Such an apparatus construction permits fuel combustion efficiency to be enhanced due to the formation of thin films (c) of fuel resultant from the impingement of the fuel jets upon the hard surface of the deflector, as well as due to the cooling of the deflector walls and those of the apparatus, disposed in a high-temperature zone, which cooling is effected by means of the fuel jets projected thereon with the resultant release of heat to be effectively used for fuel combustion; the versatility of such an apparatus is ensured through unhindered use of liquid and gaseous fuels capable of intermixing with an oxidant at a rapid rate.

Such mutual disposition of the deflector and the outlet nozzle of the fuel inlet pipe allows the fuel and oxidant intermixing to proceed at a rapid rate beyond the outlet opening of the apparatus chamber within a requisite distance therefrom, and renders the apparatus capable of operation with both hot and cold blowing used for combustion of liquid and gaseous fuel.

With the angle (P) of incidence of fuel jets less than 900 or equal to 1800, a thin film (c) of fuel will not be formed on the hard surface of the deflector, as a result of which the mixing process and, consequently, the fuel combustion efficiency will be impaired.

The deflector is preferably positioned at the outlet end of the chamber and is offset toward one of its walls.

Such a deflector arrangement makes it possible to prevent the blocking of the fuel outlet passages with molten material in the event of using the apparatus in a melting furnace. It also becomes possible to ensure an uninterrupted supply of fuel, to clean the apparatus chamber without damaging the fuel inlet pipes or blocking the fuel inlet passages with the melt, and to render the operations of replacing the fuel inlet pipes and preparing the apparatus for service in a melting unit less time- and labour-consuming.

The deflector is preferably in the form of a headpiece fixed on the chamber for oxidant at the side of the fuel outlet nozzles, whereby the service life of a burner is increased.

It is preferable that the deflector be arranged relative to the outlet nozzle of the fuel inlet pipe so that the distance (I) from the imaginary point of intersection of the nozzle axis with the deflector surface to its edge is 0.5 to 3 times the diameter (d) of the nozzle, and the distance (11) from the indicated point to the end of the outlet nozzle is 0.25 to 4 times this diameter.

In this way it becomes feasible to ensure optimum conditions for efficient combustion of fuel with the resultant formation of luminous high-temperature flame, to reduce power inputs and raise effectiveness of the process by providing uniform distribution of fuel in the oxidant (b).

With "I" being less than 0.5 times the diameter of the nozzle, a thin film (c) of fuel will not form on the hard surface of the deflector and the fuel combustion efficiency will not be enhanced.

If, however, "I" is more than 3 times the nozzle diameter, resistance to movement of the fuel film (c) along the hard surface of the deflector will be raised, kinetic energy of a thin jet (a) reduced, and the thin film (c) leaving the hard surface will not penetrate deep enough into the flow of oxidant.

This, in turn, will result in non-uniform distribution of fuel in the oxidant (b), a longer flame and a lower flame temperature.

When "11" is less than 0.25 times the nozzle diameter, a sharp increase in resistance to the flow of fuel will occur between the end face of the fuel outlet nozzle and the hard surface of the deflector, which necessitates additional energy requirements for overcoming this resistance.

If "I," is more than 4 times the nozzle diameter, the fuel in the boundary layers of the jet (a) will be partially mixed with the oxidant (b) and then will be ignited over the hard surface of the deflector, thereby causing overheating and melting-down of the deflector walls.

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a longitudinal sectional view of an apparatus for feeding a fuel into an oxidizing atmosphere during fuel combustion; Fig. 2 is a cross-section on line Il-Il of Fig. 1:: Fig. 3 shows an embodiment of the invention in which a deflector is disposed at the outlet end of a chamber in proximity with the upper wall of the latter; Fig. 4 is a section on line IV--IV of Fig. 3; Fig. 5 shows an embodiment of the invention in which a deflector is disposed at the outlet end of a fuel inlet pipe and with a chamber of rectangular cross section; Fig. 6 is a cross section on line VI--VI of Fig. 5; Fig. 7 is a cross section on line VIl-VIl of Fig.

5; Fig. 8 shows an embodiment of the invention with a deflector made in the form of a headpiece fixed on a chamber for an oxidant at the side of fuel outlet nozzles; Fig. 9 is a cross section on line IX-IX of Fig. 8, with an oxidant chamber of circular cross section; Fig.10 is a cross section on line X-X of Fig.

8, with an oxidant chamber of rectangular cross section; and Fig. 11 shows an embodiment of the invention with a deflector fixed in position along the centre line of a fuel inlet pipe.

The method of the invention for feeding a fuel into an oxidizing atmosphere is performed by apparatus as designated above.

The apparatus comprises a chamber 1 for receiving an oxidant (b) therein and equipped with fuel inlet pipes 2 fitted with outlet nozzles 3 for producing fuel jets (a). Arranged in opposite spaced relationship with the outlet nozzles 3 of the fuel inlet pipes 2 is at least one deflector 4 formed with a hard surface 5 for forming thin films (c) of fuel from the fuel jets (a).The deflector 4 and the outlet nozzle 3 of the fuel inlet pipe 2 are mutually arranged so as to permit the angle of incidence (p) to be more than or equal to 900 and not less than 1 800 (Fig. 3). The deflector 4 may be arranged in symmetry with the outlet nozzle 3 (Figs. 1, 2) or otherwise positioned at the outlet end of the chamber 1 so as to be offset toward one of its walls (Figs. 3, 4). The deflector 4 may be made in the form of a headpiece fixed on the chamber 1 at the side of the fuel outlet nozzles 3, such as is shown in Figs. 8, 9. It is sometimes preferred to employ an embodiment of the invention wherein the deflector 4 is positioned at the outlet end of the fuel inlet pipe 2 being rectangular in cross section, such as is shown in Figs. 5-7, or still another embodiment of the invention according to which the deflector 4 is arranged along the centre line of the fuel inlet pipe 2, such as is shown in Fig. 11. The chamber 1 for oxidant may be rectangular in cross section, such as is shown in Figs. 1-6, 10, circular, such as is shown in Fig. 9, triangular, multi-angular, oval, or of any other more complex shape.The rigid or hard surface 5 of the deflector 4 may be flat, concave or convex with respect to the end face of the outlet nozzle 3, or alternatively of conical, pyramidal or more complex geometric form. The wall of the deflector 4 may have any shape suitable for each given case.

To create the best possible conditions for the formation of a thin fuel film (c) on the hard surface 5 of the deflector 4, and to permit deep penetration of the fuel film (c) leaving this surface to be mixed with the oxidant (b), the deflector 4 is arranged relative to the outlet nozzle 3 of the fuel inlet pipe 2 so that the distance "I" from the imaginary point of intersection of the axis of the nozzle 3 with the surface 5 of the deflector 4 to its edges is 0.5 to 3 times the diameter of the nozzle 3, and the distance "11" from the indicated point to the end face of the outlet nozzle 3 is 0.25 to 4 times this diameter (Figs. 8, 11).

The surface 5 of the deflector 4 may be electrically heated from a power source connected to the deflector 4 (Fig. 2).

The method of the invention is performed as follows.

First, an oxidant (b) is admitted through an inlet pipe into the chamber 1 and then a flow of fuel is supplied to the fuel inlet pipes 2 in the direction of arrow A (Figs. 1,2). It is possible to use any kind of fuel, for example, liquid (black oil or kerosene) or gaseous (natural gas, methane, propane, butane, acetylen, hydrogen or producer gas). Cold or hot air, oxygen enriched air or oxygen may be used as the oxidant (b).

The fuel inlet pipes 2 are formed with the outlet nozzles (3) adapted to produce highvelocity jets (a) of fuel, the speed of which is greater than that of the oxidant (b). These fuel jets (a) are projected against a hard surface 5 of a deflector 4 until their interaction with the oxidant (b). As this happens, the fuel spreads over the hard surface 5 of the deflector 4 in different directions and thin films (c) are formed from the fuel jets (a). The resultant thin films (c) of fuel leave the hard surface 5 of the deflector 4 and pass into the oxidant (b), whereby the process of the fuel and oxidant intermixing is intensified to accelerate the process of formation of the combustible mixture of a required composition and its ignition. As a result, the length of flame is shortened and its temperature is raised.

The length of flame will be drastically reduced if, alongside the formation of thin films (c) of fuel on the hard surface 5 of the deflector 4, this hard surface 5 is concurrently heated thereby to permit heating of the fuel thin films (c) deflected therefrom into the oxidant (b).

These thin fuel films (c) should be heated to an initial temperature of fuel dissociation. By feeding the dissociated fuel into the oxidant (b), it becomes possible to ensure a further decrease in the length of flame and temperature increase in the volume of combustion products. This, in turn, will result in a higher temperature of the flame due to deep penetration of the fuel films (c) into the oxidant and rapid formation of the combustible mixture, as well as in a higher rate of burning brought about by the presence of the fuel decomposition products in the combustible mixture.For example, if natural gas is used as the fuel, the main component of which is methane, with an initial temperature of dissociation being 3000C, then by raising the fuel temperature from 3000C to 1100--i 2000C, the temperature of complete dissociation of methane, it becomes possible to reduce the length of flame along with an increase in the fuel heating temperature.With natural gas being heated on the hard surface 5 of the deflector 4 to a temperature of 1100- 1 2000 C, and with the products of fuel dissociation introduced straight into the oxidant (b) in the form of thin films (c), the combustion of these products will proceed at the moment of the fuel and oxidant intermixing, as a result of which, all other conditions being equal, it becomes possible to achieve a maximum temperature in the volume of combustion products.

The heating of the fuel films (c) may be by means of heat transfer from the burning fuel through the hard surface 5 of the deflector 4, as well as by passing electric current through the hard surface 5 (Fig. 2). In the latter case, the hard surface 5 of the deflector 4 should be made from a material with a high electrical resistance, such as stainless refractory steel.

Ciaims 1. A method of feeding a fuel into an oxidizing atmosphere during fuel combustion, comprising produced jets of fuel and causing these jets to interact with an oxidant, wherein, prior to interaction with the oxidant, the fuel jets are projected against a hard surface and, on their impingement upon the latter, are formed into thin films which flow off the hard surface into the oxidant in order to interact therewith.

2. A method according to claim 1 , wherein after impingement upon the hard surface, the fuel films are heated.

3. A method according to claim 2, wherein the fuel films are heated to an initial temperature of fuel dissociation and above this temperature.

4. A method according to claim 2, wherein the fuel films are heated by means of the heat transferred from the burning fuel tough the hard surface.

5. A method according to claim 2, wherein the fuel films are heated by an electric current passed through the hard surface.

6. Apparatus for performing the method of any of claims 1 to 5, comprising a chamber intended to receive an oxidant and having fuel inlet pipes formed with outlet nozzles adapted to produce jets of fuel, at least one deflector with a hard surface being arranged opposite the outlet nozzles and serving for the formation of thin films from the fuel jets.

7. Apparatus according to Claim 6, wherein the deflector and the outlet nozzle of the fuel inlet pipe are mutually arranged so that the angle (p) of incidence of the fuel jets (a) is more than or equal to 900 and less than 1 800.

8. Apparatus according to claim 6, wherein the deflector is at the outlet end of the chamber and is offset from the centre toward one of the chamber walls.

9. Apparatus according to claim 6, wherein the deflector is in the form of a headpiece fixed at the side of the fuel outlet nozzles.

1 0. Apparatus according to claim 6, wherein the deflector is so arranged relative to the outlet nozzle of the fuel inlet pipe that the distance (I) from the imaginary point of intersection of the axis of the nozzle with the surface of the deflector to its edges is 0.5 to 3 times the diameter of the outlet nozzle, and the distance (I,) from the indicated point to the end face of the outlet nozzle is 0.25 to 4 times this diameter.

11. A method of feeding a fuel into an oxidizing atmosphere substantially as hereinbefore described by reference to Figs. 1 and 2, Figs. 3 and 4, Figs. 5, 6 and 7, Figs. 8, 9 and 10 or Fig.

11 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (12)

**WARNING** start of CLMS field may overlap end of DESC **. or gaseous (natural gas, methane, propane, butane, acetylen, hydrogen or producer gas). Cold or hot air, oxygen enriched air or oxygen may be used as the oxidant (b). The fuel inlet pipes 2 are formed with the outlet nozzles (3) adapted to produce highvelocity jets (a) of fuel, the speed of which is greater than that of the oxidant (b). These fuel jets (a) are projected against a hard surface 5 of a deflector 4 until their interaction with the oxidant (b). As this happens, the fuel spreads over the hard surface 5 of the deflector 4 in different directions and thin films (c) are formed from the fuel jets (a). The resultant thin films (c) of fuel leave the hard surface 5 of the deflector 4 and pass into the oxidant (b), whereby the process of the fuel and oxidant intermixing is intensified to accelerate the process of formation of the combustible mixture of a required composition and its ignition. As a result, the length of flame is shortened and its temperature is raised. The length of flame will be drastically reduced if, alongside the formation of thin films (c) of fuel on the hard surface 5 of the deflector 4, this hard surface 5 is concurrently heated thereby to permit heating of the fuel thin films (c) deflected therefrom into the oxidant (b). These thin fuel films (c) should be heated to an initial temperature of fuel dissociation. By feeding the dissociated fuel into the oxidant (b), it becomes possible to ensure a further decrease in the length of flame and temperature increase in the volume of combustion products. This, in turn, will result in a higher temperature of the flame due to deep penetration of the fuel films (c) into the oxidant and rapid formation of the combustible mixture, as well as in a higher rate of burning brought about by the presence of the fuel decomposition products in the combustible mixture.For example, if natural gas is used as the fuel, the main component of which is methane, with an initial temperature of dissociation being 3000C, then by raising the fuel temperature from 3000C to 1100--i 2000C, the temperature of complete dissociation of methane, it becomes possible to reduce the length of flame along with an increase in the fuel heating temperature.With natural gas being heated on the hard surface 5 of the deflector 4 to a temperature of 1100- 1 2000 C, and with the products of fuel dissociation introduced straight into the oxidant (b) in the form of thin films (c), the combustion of these products will proceed at the moment of the fuel and oxidant intermixing, as a result of which, all other conditions being equal, it becomes possible to achieve a maximum temperature in the volume of combustion products. The heating of the fuel films (c) may be by means of heat transfer from the burning fuel through the hard surface 5 of the deflector 4, as well as by passing electric current through the hard surface 5 (Fig. 2). In the latter case, the hard surface 5 of the deflector 4 should be made from a material with a high electrical resistance, such as stainless refractory steel. Ciaims

1. A method of feeding a fuel into an oxidizing atmosphere during fuel combustion, comprising produced jets of fuel and causing these jets to interact with an oxidant, wherein, prior to interaction with the oxidant, the fuel jets are projected against a hard surface and, on their impingement upon the latter, are formed into thin films which flow off the hard surface into the oxidant in order to interact therewith.

2. A method according to claim 1 , wherein after impingement upon the hard surface, the fuel films are heated.

3. A method according to claim 2, wherein the fuel films are heated to an initial temperature of fuel dissociation and above this temperature.

4. A method according to claim 2, wherein the fuel films are heated by means of the heat transferred from the burning fuel tough the hard surface.

5. A method according to claim 2, wherein the fuel films are heated by an electric current passed through the hard surface.

6. Apparatus for performing the method of any of claims 1 to 5, comprising a chamber intended to receive an oxidant and having fuel inlet pipes formed with outlet nozzles adapted to produce jets of fuel, at least one deflector with a hard surface being arranged opposite the outlet nozzles and serving for the formation of thin films from the fuel jets.

7. Apparatus according to Claim 6, wherein the deflector and the outlet nozzle of the fuel inlet pipe are mutually arranged so that the angle (p) of incidence of the fuel jets (a) is more than or equal to 900 and less than 1 800.

8. Apparatus according to claim 6, wherein the deflector is at the outlet end of the chamber and is offset from the centre toward one of the chamber walls.

9. Apparatus according to claim 6, wherein the deflector is in the form of a headpiece fixed at the side of the fuel outlet nozzles.

1 0. Apparatus according to claim 6, wherein the deflector is so arranged relative to the outlet nozzle of the fuel inlet pipe that the distance (I) from the imaginary point of intersection of the axis of the nozzle with the surface of the deflector to its edges is 0.5 to 3 times the diameter of the outlet nozzle, and the distance (I,) from the indicated point to the end face of the outlet nozzle is 0.25 to 4 times this diameter.

11. A method of feeding a fuel into an oxidizing atmosphere substantially as hereinbefore described by reference to Figs. 1 and 2, Figs. 3 and 4, Figs. 5, 6 and 7, Figs. 8, 9 and 10 or Fig.

11 of the accompanying drawings.

12. Apparatus for feeding fuel into an oxidizing

atmosphere substantially as hereinbefore described with reference to and as shown in the accompanying drawings.