GB2064095A - Rotary atomizer - Google Patents

Abstract

A boiler (1) in which the flame changes direction at the rear end of the firebox so as to flow through said firebox in the opposite direction, having a water jacket and a firebox (5) which is sealed at the rear and is closed by a door (12) at the front of the boiler. A burner arrangement (7) in the door (12) is provided with a rotary atomiser (9), surrounded by an annular air channel (10). The boiler door (12) is provided with an insulating layer (13) and a fire-clay door lining (16). A combustion tube insert (14) is mounted in the firebox (5) so as to be substantially flush with the fire-clay door lining (16) when the door is closed. This combustion tube insert (14) may be constructed as a double metal tube lined on the inside with a refractory lining (17), preferably of fire-clay, the annular chamber of which is connected to the water jacket (3) via connectors, so as to effect cooling of the combustion tube insert (14). <IMAGE>

Description

SPECIFICATION Improvements in boilers This invention relates to a boiler with a firebox sealed at the rear and with smoke flues ending in the region of the boiler door for receiving the flue gas.

In boilers, whether they be steam, water or heating boilers, wherein the flame reverses at the rear closed end of the firebox in order to flow through said firebox in the opposite direction, it is not possible to use rotary atomising burners unless the firebox is enlarged. This would make these boilers larger and more expensive. The normal ratio of dimensions of the firebox in such boilers is a ratio of diameter to length equal to or less than 1, e.g. 1:2.5 t 3, i.e. around 1: 0.7, and the load in the firebox should be 21 o6 kcal/m3h. It has not been possible to use rotary atomising burners, owing to the expansive flame produced when burners of this kind are used for these fireboxes and owing to the unfavourable flow characteristics of the flame and flue gases.

This applies to the combustion of both light and very heavy oil.

The aim of this invention is to design the firebox of a boiler of this kind for water to steam so that rotary atomising burners can also be used successfully without having to increase the size of the firebox. This is of particular importance with large-capacity boilers and/or when burning very heavy oils.

This aim is achieved by the combination of a rotary atomising burner, which forms part of a burner mounted on the door of the boiler, and a flame-guiding insert mounted behind said atomiser and projecting into the firebox and consisting at least partially of refractory material.

The object of the invention is hereinafter explained by way of example with reference to a drawing, showing a longitudinal section through the front portion of a heating boiler of the kind described above, known as a heating boiler with flame return.

In the front part of this boiler 1 are shown a water jacket 3 and part of the firebox 5, sealed off at the rear, with a burner arrangement 7. This arrangement 7 is provided with a rotary atomiser 9 surrounded by an annular air channel 10. The burner arrangement 7 is mounted in and on the door 12 of the boiler. The boiler door 12 is provided with an insulating layer 13 and a fire-clay door lining 16. With the boiler door 12 closed, the drawing shows a combustion pipe insert 14 essentially flush with the fire-clay door lining 16.

This combustion pipe insert 14 may, for example, be in the form of a double metal tube lined on the inside with a refractory lining 17, preferably of fire-clay, the annular chamber of which is connected to the water jacket 3 via connectors, so as to cool the combustion pipe insert 14.

At higher pressures, it is advantageous to provide a coil of pipe instead of the double pipe shown in the drawing. This coil of pipe then cools the metal inner casing 1 8 which carries the fireclay lining 17, or else the refractory material 1 7 is mounted directly on said coil. Connectors 20 permit the necessary circulation of cooling fluid.

It is also possible to fit an insert of refractory material, which may be reinforced with iron if necessary. After changing direction at the closed end of the boiler, the combustion gases in the firebox 5 pass through the annular flue gas channel 22 into the corresponding channel in the boiler door 12 and from there pass through smoke flues into the flue gas discharge, as is known in principle frorn the prior art.

The flame which forms licks round the entire inside of the combustion pipe insert 14. The free end of this insert is constructed as an acceleration baffle which imparts to the flame or to the flame gases the stability required to ensure the desired thermal load on the firebox.

This insert enables heating boilers of this kind with flame return to operate satisfactorily, even with very heavy oil, with the burner arrangement supplied by rotary atomising burners.

1. A boiler comprising a firebox which is sealed at the rear and is closed at the front of the boiler by a door, smoke flues arranged for receiving the flue gas in the region of said door, a burner, including a rotary atomiser, mounted on the said door, and a fiame-guiding insert mounted behind said atomiser so as to project into the firebox, said insert consisting at least partially of refractory material.

2. A boiler according to Claim 1, wherein the flame guiding insert is constructed as a steel tube lined with a refractory material.

3. A boiler according to Claim 2 wherein the refractory material is in the form of a stselreinforced refractory lining.

4. A boiler according to any of Claims 1-3 wherein the flame guiding insert comprises a water-cooling means.

5. A boiler according to Claim 4 wherein the water cooling means comprises a water jacket.

6. A boiler according to Claim 4 wherein the water cooling means comprises a cooling coil wound around the insert.

7. A boiler according to Claim 5, wherein the water-cooling jacket is connected to the water ways of the boiler via at least two water connectors contained in the firebox.

8. A boiler according to any preceding claim wherein the end of the flame guiding insert rernote from the door is constructed as a throat.

9. A boiler according to Claim 2 or any claim appendant thereto wherein the ratio of the internal diameter of the said tube to its length is S1.

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

Claims (11)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in boilers This invention relates to a boiler with a firebox sealed at the rear and with smoke flues ending in the region of the boiler door for receiving the flue gas. In boilers, whether they be steam, water or heating boilers, wherein the flame reverses at the rear closed end of the firebox in order to flow through said firebox in the opposite direction, it is not possible to use rotary atomising burners unless the firebox is enlarged. This would make these boilers larger and more expensive. The normal ratio of dimensions of the firebox in such boilers is a ratio of diameter to length equal to or less than 1, e.g. 1:2.5 t 3, i.e. around 1: 0.7, and the load in the firebox should be 21 o6 kcal/m3h. It has not been possible to use rotary atomising burners, owing to the expansive flame produced when burners of this kind are used for these fireboxes and owing to the unfavourable flow characteristics of the flame and flue gases. This applies to the combustion of both light and very heavy oil. The aim of this invention is to design the firebox of a boiler of this kind for water to steam so that rotary atomising burners can also be used successfully without having to increase the size of the firebox. This is of particular importance with large-capacity boilers and/or when burning very heavy oils. This aim is achieved by the combination of a rotary atomising burner, which forms part of a burner mounted on the door of the boiler, and a flame-guiding insert mounted behind said atomiser and projecting into the firebox and consisting at least partially of refractory material. The object of the invention is hereinafter explained by way of example with reference to a drawing, showing a longitudinal section through the front portion of a heating boiler of the kind described above, known as a heating boiler with flame return. In the front part of this boiler 1 are shown a water jacket 3 and part of the firebox 5, sealed off at the rear, with a burner arrangement 7. This arrangement 7 is provided with a rotary atomiser 9 surrounded by an annular air channel 10. The burner arrangement 7 is mounted in and on the door 12 of the boiler. The boiler door 12 is provided with an insulating layer 13 and a fire-clay door lining 16. With the boiler door 12 closed, the drawing shows a combustion pipe insert 14 essentially flush with the fire-clay door lining 16. This combustion pipe insert 14 may, for example, be in the form of a double metal tube lined on the inside with a refractory lining 17, preferably of fire-clay, the annular chamber of which is connected to the water jacket 3 via connectors, so as to cool the combustion pipe insert 14. At higher pressures, it is advantageous to provide a coil of pipe instead of the double pipe shown in the drawing. This coil of pipe then cools the metal inner casing 1 8 which carries the fireclay lining 17, or else the refractory material 1 7 is mounted directly on said coil. Connectors 20 permit the necessary circulation of cooling fluid. It is also possible to fit an insert of refractory material, which may be reinforced with iron if necessary. After changing direction at the closed end of the boiler, the combustion gases in the firebox 5 pass through the annular flue gas channel 22 into the corresponding channel in the boiler door 12 and from there pass through smoke flues into the flue gas discharge, as is known in principle frorn the prior art. The flame which forms licks round the entire inside of the combustion pipe insert 14. The free end of this insert is constructed as an acceleration baffle which imparts to the flame or to the flame gases the stability required to ensure the desired thermal load on the firebox. This insert enables heating boilers of this kind with flame return to operate satisfactorily, even with very heavy oil, with the burner arrangement supplied by rotary atomising burners. CLAIMS

1. A boiler comprising a firebox which is sealed at the rear and is closed at the front of the boiler by a door, smoke flues arranged for receiving the flue gas in the region of said door, a burner, including a rotary atomiser, mounted on the said door, and a fiame-guiding insert mounted behind said atomiser so as to project into the firebox, said insert consisting at least partially of refractory material.

2. A boiler according to Claim 1, wherein the flame guiding insert is constructed as a steel tube lined with a refractory material.

3. A boiler according to Claim 2 wherein the refractory material is in the form of a stselreinforced refractory lining.

4. A boiler according to any of Claims 1-3 wherein the flame guiding insert comprises a water-cooling means.

5. A boiler according to Claim 4 wherein the water cooling means comprises a water jacket.

6. A boiler according to Claim 4 wherein the water cooling means comprises a cooling coil wound around the insert.

7. A boiler according to Claim 5, wherein the water-cooling jacket is connected to the water ways of the boiler via at least two water connectors contained in the firebox.

8. A boiler according to any preceding claim wherein the end of the flame guiding insert rernote from the door is constructed as a throat.

9. A boiler according to Claim 2 or any claim appendant thereto wherein the ratio of the internal diameter of the said tube to its length is S1.

10. A boiler according to Claim 9 wherein said ratio is 0.7.

11. A boiler substantially as described herein with reference to the accompanying drawing.