GB1573081A - Oxy fuel burner - Google Patents

Description

(54) OXY-FUEL BURNER (71) We, MESSER GRIESHEIM GUSH.

a Company organised under the laws of the Federal Republic of Germany, of Hanauer Landstr. 330, D-6000 Frankfurtl Main, Federal Republic of Germany, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to an oxy-fuel burner of the kind having an oxygen tube and a fuel tube connected to a burner head having a mixing chamber in which a combustible mixture is formed.

Oxy-fuel burners are used where very high temperatures are needed - which cannot be achieved- with air-fuel burners. High temperatures of this kind are required for example in the melting-off of slag in melting furnaces. Because of the very high temperatures the mixing chamber of the burner is subject to heavy wear and, to achieve a longer life, the mixing chamber must be cooled, Cooling is generally effected with a water cooling system but this increases the weight of the burner so that it becomes-less manageable. Use of the burner also becomes more complicated, because an additional water supply is required for operating the burner. In addition, the functioning of the burner may be impaired by deposits from the water.

The object of the present invention is to provide an oxy-fuel burner in which no additional cooling medium is required for cooling purposes and which nevertheless has an adequately long life.

According to the present invention, there is provided an oxy-fuel burner, comprising an oxygen tube and a fuel tube which open into a burner head having a mixing chamber in which a combustible mixture is formed, a tubular fuel nozzle disposed in the burner head in a direction coaxial with the axis of the mixing chamber, an annular swirl chamber in the burner head and having a lateral, tangential or substantially tangential, inlet aperture for the oxygen, the mixing chamber being outwardly flared from the - outlet aperture of the swirl chamber.

The burner head and the combustion chamber are preferably made in one piece.

The most advantageous cone angle for the mixing chamber is to 30 , although cone angles between 20 and 45" are also very suitable.

In the oxy-fuel burner of the invention the chamber is cooled by the oxygen itself: Thus, as the oxygen passes out of the swirl chamber into the mixing chamber it is caused to rotate rapidly and this rotary movement forces it against the flared mixing chamber. The wall of the mixing chamber is thereby cooled. - Surprisingly, as soon as it reaches the region pf the mixing chamber outlet, a large gro- portion of the oxygen returns in the axial direction into the mixing chamber. Intensive mixing with the fuel passing out in the axial direction is thereby effected. For this purpose the fuel may be gaseous or liquid.

Owing to the fact that the oxygen flow cools the burner, particularly the chamber itself, no additional cooling medium is required. The burner thus becomes light and easily manageable and is capable of universal use.

One embodiment of the invention is illustrated by way-- of--example in the-accom- panying drawings, in which: Figure 1 is a longitudinal section through a burner according to the invention Figure 2 is a section through the burner head with the burner chamber, Figure 3 is a section on the line A-B of Figure 2, and Figure 4 is a view illustrating the flow conditions in the combustion chamber.

Referring to Figures 1 to 3 of the drawings, an oxy-fuel burner comprises a fuel tube 4 which is surrounded by an oxygen supply tube 3. The oxygen enters the tube 3 through a branch tube 1 opening out into a collecting chamber 2 and thence into the annual space formed between the oxygen tube 3 and the fuel tube 4. Both tubes connect with a burner head 6, which is extended to provide a mixing chamber 9 in one piece therewith. The fuel passes into a fuel chamber 10 and thence through a fuel nozzle 8 which is coaxial with the mixing chamber 9. The oxygen first passes into an annular oxygen chamber 5 and thence through a tangential bore 11 into a swirl chamber 7. Because the oxygen enters tangentially, an extremely high speed of rotation is imparted to it in the swirl chamber 7.The fuel nozzle 8 extends in the axial direction through the swirl chamber 7 and is secured in the burner head by a cotter pin 12. The outlet end of the fuel nozzle 8 lies in the same plane as the annular outlet opening of the swirl chamber 7. The mixing chamber 9, which is flared outwardly, directly adjoins the annular outlet opening of the swirl chamber 7. The oxygen also retains in the mixing chamber 9 the rotary movement imparted to it in the swirl chamber 7 and is forced against the wall of the mixing chamber 9. The mixing chamber 9 is thereby cooled, firstly because it does not come into contact with hot combustion gases, and secondly because the rapidly flowing oxygen intensively cools the mixing chamber wall.

At the same time, however, a large proportion of the rotating oxygen flows back to the outlet openings for the fuel and oxygen. It thus impinges on the outflowing fuel, so that oxygen and fuel are intensively mixed. The flow conditions in the mixing chamber are indicated in Figure 4 by arrows 13 for the fuel and arrows 14 for the oxygen. Therefore, the fuel stream 15 (Figure 1) passing out in an axial direction, and the rotating oxygen stream 16 (Figure 1), substantially completely mixed with one another by the time they pass out of the mixing chamber 9. Optimum conditions for good flame formation are thus achieved.

Various modifications of the oxy-fuel burner described are possible. Fuel and oxygen may for example be introduced into the burner head through separate tubes.

The commencement of the flaring of the mixing chamber need not lie in the plane of the outlet openings of the fuel nozzle and swirl chamber. The burner head need not be made in one piece, as shown in Figures 1 and 2, but may also be made in two pieces. In this case a particularly heat-resistant material may be used for the mixing chamber.

WHAT WE CLAIM IS: 1. An oxy-fuel burner, comprising an oxygen tube and a fuel tube which open into a burner head having a mixing chamber in which a combustible mixture is formed, a tubular fuel nozzle disposed in the burner head in a direction coaxial with the axis of the mixing chamber, an annular swirl chamber in the burner head and having a lateral, tangential or substantially tangential, inlet aperture for the oxygen, the mixing chamber being outwardly flared from the outlet aperture of the swirl chamber.

2. An oxy-fuel burner according to claim 1, wherein the burner head and mixing chamber are in one piece.

3. An oxy-fuel burner according to claim 1 or claim 2, wherein the cone angle of the flared portion of the mixing chamber is between 20 and 45 .

4. An oxy-fuel burner according to claim 3, in which the cone angle is 30".

5. An oxy-fuel burner, substantially as hereinbefore described with reference to the accompanying drawings.

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

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. conditions in the combustion chamber. Referring to Figures 1 to 3 of the drawings, an oxy-fuel burner comprises a fuel tube 4 which is surrounded by an oxygen supply tube 3. The oxygen enters the tube 3 through a branch tube 1 opening out into a collecting chamber 2 and thence into the annual space formed between the oxygen tube 3 and the fuel tube 4. Both tubes connect with a burner head 6, which is extended to provide a mixing chamber 9 in one piece therewith. The fuel passes into a fuel chamber 10 and thence through a fuel nozzle 8 which is coaxial with the mixing chamber 9. The oxygen first passes into an annular oxygen chamber 5 and thence through a tangential bore 11 into a swirl chamber 7. Because the oxygen enters tangentially, an extremely high speed of rotation is imparted to it in the swirl chamber 7.The fuel nozzle 8 extends in the axial direction through the swirl chamber 7 and is secured in the burner head by a cotter pin 12. The outlet end of the fuel nozzle 8 lies in the same plane as the annular outlet opening of the swirl chamber 7. The mixing chamber 9, which is flared outwardly, directly adjoins the annular outlet opening of the swirl chamber 7. The oxygen also retains in the mixing chamber 9 the rotary movement imparted to it in the swirl chamber 7 and is forced against the wall of the mixing chamber 9. The mixing chamber 9 is thereby cooled, firstly because it does not come into contact with hot combustion gases, and secondly because the rapidly flowing oxygen intensively cools the mixing chamber wall. At the same time, however, a large proportion of the rotating oxygen flows back to the outlet openings for the fuel and oxygen. It thus impinges on the outflowing fuel, so that oxygen and fuel are intensively mixed. The flow conditions in the mixing chamber are indicated in Figure 4 by arrows 13 for the fuel and arrows 14 for the oxygen. Therefore, the fuel stream 15 (Figure 1) passing out in an axial direction, and the rotating oxygen stream 16 (Figure 1), substantially completely mixed with one another by the time they pass out of the mixing chamber 9. Optimum conditions for good flame formation are thus achieved. Various modifications of the oxy-fuel burner described are possible. Fuel and oxygen may for example be introduced into the burner head through separate tubes. The commencement of the flaring of the mixing chamber need not lie in the plane of the outlet openings of the fuel nozzle and swirl chamber. The burner head need not be made in one piece, as shown in Figures 1 and 2, but may also be made in two pieces. In this case a particularly heat-resistant material may be used for the mixing chamber. WHAT WE CLAIM IS:

1. An oxy-fuel burner, comprising an oxygen tube and a fuel tube which open into a burner head having a mixing chamber in which a combustible mixture is formed, a tubular fuel nozzle disposed in the burner head in a direction coaxial with the axis of the mixing chamber, an annular swirl chamber in the burner head and having a lateral, tangential or substantially tangential, inlet aperture for the oxygen, the mixing chamber being outwardly flared from the outlet aperture of the swirl chamber.

2. An oxy-fuel burner according to claim 1, wherein the burner head and mixing chamber are in one piece.

3. An oxy-fuel burner according to claim 1 or claim 2, wherein the cone angle of the flared portion of the mixing chamber is between 20 and 45 .

4. An oxy-fuel burner according to claim 3, in which the cone angle is 30".

5. An oxy-fuel burner, substantially as hereinbefore described with reference to the accompanying drawings.