GB2062211A

GB2062211A - Wide flame burner

Info

Publication number: GB2062211A
Application number: GB8031688A
Authority: GB
Original assignee: Shell Internationale Research Maatschappij BV
Current assignee: Shell Internationale Research Maatschappij BV
Priority date: 1979-10-03
Filing date: 1980-10-01
Publication date: 1981-05-20
Also published as: FR2466707B1; JPS5661511A; GB2062211B; FR2466707A1; DE3037106A1; CA1138323A

Abstract

A burner for firing metal or glass products comprises a known body 10 for imparting rotation to a mixture of fuel gas and air and a burner head 12 comprising a generally spherical interior chamber 50 connected to the burner body by means of a passage 42 which converges in the direction of the chamber; and an elongated opening 58 connected to the chamber by means of a passage 54 with walls 62, 64 diverging in the direction of the opening, one large side of the opening comprising a ridge 74 and a curved section 72 and the other large side of the opening comprising a second ridge 56. The flame is shaped by moving the relative positions of parts 32 and 34 along the joint line 36 so as to adjust the space between the ridges. <IMAGE>

Description

SPECIFICATION Burner designed to produce a wide flame The present invention relates to a burner designed to produce a wide and adjustable flame and which is particularly suitable for firing metal or glass products.

In order to carry out the firing with a wide flame of products, in particular glass products, by the "burning" technique use has so far been made of oxygen burners the main drawback of which is the high firing cost.

The object of the invention is to obviate this drawback by proposing a novel burner which operates on a mixture of fuel gas and air and which is capable of producing a wide flame of varying thickness.

The burner according to the invention permits complete firing at elevated temperature, even in the open air, of products having a length-width ratio or which are very thin, while these products pass along or rotate in front of the burner or the local heating of more solid products. This burner may also be used in an enclosed firing space where the temperatures achieved could be higher but where the local heating possibilities will be more limited.

A burner of this type will therefore preferably be used for the "reburning" of glass products, although it can equally well be used as open forging furnace or as burner for a kiln for ceramic products in which a thin, wide flame is required.

The burner according to the invention is based on the flow of a homogeneous mixture of air and fuel gas introduced through a burner body fixed to a burner head having an opening of a suitable asymmetrical shape which makes it possible to obtain a wide flame of more or less rectangular cross-section in the direction of flow and which, under certain conditions, can even be triangular like the tip-like flame of an intensive burner.

The present invention relates more in particular to a burner designed to produce a wide flame, comprising a burner body for imparting rotation to a mixture of fuel gas and air and a burner head integral with the burner body, characterized in that the burner head comprises a generally spherical interior chamber connected to the burner body by means of a passage which converges in the direction of the chamber; and an elongated opening which can generate the flame, which is connected to the chamber by means of a passage which diverges in the direction of the opening, one large side of the opening comprising a first ridge and a curved section and the other large side of the opening comprising a second ridge.

The first ridge and the second ridge of the opening permit limited displacement in relation to each other depending on the shape which it is desired to give to the flame.

In a preferred embodiment of the invention the diverging passage comprises two opposite parallel walls connected at the two large sides of the opening and the converging passage has an axis of rotation normal to the two parallel walls opposite the diverging passage.

According to another characteristic of this embodiment the interior chamber is spherical and the head of the burner is formed of two parts of which one comprises the converging passage, one of the parallel walls opposite the diverging passage and a spherical semi-dome forming one half of the interior chamber and the other part comprises the other parallel wall opposite the diverging passage, the two diverging walls of the diverging passage and a spherical semi-dome forming the other half of the interior chamber.

The burner according to the invention also comprises fixing means which can interconnect the two parts of the burner head so that they can be adjusted by sliding the two parts along a mating plane parallel to the parallel walls opposite the diverging passage.

The first ridge of the opening preferably comprises a stepped section.

The burner head of the invention is preferably made of a refractory material, although it may also be made of a metal which is cooled by fluid circulation.

This burner head can be a separate unit or be integral with a more complex unit, for example a furnace wall.

Other characteristics and advantages of the invention will be more clearly understood from the following description with reference to the attached drawings given solely by way of nonlimitative example, in which: Fig. 1 is a perspective view of a burner according to the invention showing a detached part of the head of the burner; Fig. 2 is a cross-section taken on line Il-lI of Fig. 1 and showing the shape of the converging passage, of the interior chamber and of the diverging passage of the burner head; Fig. 3 is a bottom view in perspective of the part of the burner head of Figs. 1 and 2, which supports the burner body; and Fig. 4 is a top plan view in perspective of the other part of the burner head.

In these Figures the same reference numbers designate the same elements.

The burner shown in Fig. 1 comprises a burner body 10 which is capable of imparting rotation to a mixture of fuel gas and air and a burner head 12 integral with the burner body 10. The burner body 10 is a metal burner body, of a known type, of mechanically assembled and welded construction or of cast metal and comprising a cylindrical tube 14 which extends into a converging tube 16 having the shape of a truncated cone which is in turn connected to an annular flange 1 8 which is perforated by securing openings such as 20 and 22 by means of which the burner body 10 can be secured on to the burner head 12.

The upstream part of the burner body 10 comprises a tangential tube 24 to admit air, a plug 26 which supports a fuel gas injection tube 28 and which is secured to a circular locking plate 30 of the burner body 10. This burner body therefore permits the combustion air and the fuel gas, the latter directly to be brought into rotation at the inlet of the burner head 12.

The burner head 12 comprises two asymmetrical parts 32 and 34 which are interconnected by suitable mechanical securing means along a mating plane 36 which is normal to the axis XX of the burner body 10. These securing means could, for example, be flanges ensuring that the sections 32 and 34 are so tightened that they can be adjusted by sliding along the mating plane 36. The two sections 32 and 34 of the burner head 12 are made of light refractory material of a composition suitable to withstand the high temperatures in the order of 1 5000C to which they will be subjected.

By way of example these two parts can be obtained by casting a light refractory paste which, after baking, has a voluminal mass between 1.2 and 1.8 kg/dm3 and preferably 1.5 kg/dm3. Such a refractory paste can, for example, be obtained by mixing Chamotte blister alumina and hightemperature cement.

As indicated before, the two parts of the burner head may also be composed of metal sections provided with cooling means.

The upper part 32 comprises stud bolts such as 38 and 40 which are capable of securing the annular flange 1 8 of the burner body 10 onto the burner head 12. The parts 32 and 34 of the burner head 12 are obtained by casting in such a way that characteristic recesses are formed which, after assembly of the two parts, will form the converging passage, the interior chamber and the diverging passage suitable for producing the desired flame.

The part 32 comprises a converging passage 42 presenting a revolving symmetry in relation to the axis XX and formed by a truncated cone. This converging passage has an inlet 44 designed to be connected to the outlet of the burner body 10 and an outlet 46 which debouches into the inlet of a spherical semi-dome 48 which is also provided in the part 32 and of which the median plane coincides with the above-mentioned mating plane 36.

This spherical semi-dome 48 forms half of a spherical interior chamber 50 arranged in the burner head 12. Similarly, the part 32 comprises a wall 52 which forms one of the two parallel walls opposite a diverging passage 54 which communicates with the chamber 50 and debouches to the outside. This wall 52 has a flat section which communicates with the interior chamber 50 and ends in a curved section 56 which is ridge-shaped and comprises the long side of an elongated opening 58 which debouches to the outside. The wall 52 is situated in the mating plane 36 between the parts 32 and 34.

The part 34 comprises a spherical semi-dome 60 of which the virtual, median plane corresponds with the mating plane 36 and which thus forms with the spherical semi-dome 48 the abovementioned chamber 50. The sides of the diverging passage 54 are limited by two diverging planar walls 62 and 64 connecting the interior chamber 50 to both short sides 66 of the opening 58. In Figs. 1 and 4, only one of the short sides 66 of the opening 58 is visible. These walls 62 and 64 are tangential to the spherical chamber 50 and widen out as they lead to the small sides of the slit 58 (see Fig. 4). The passage 54 is furthermore limited by a parallel wall opposite the wall 62 of the part 32. This wall obtained by casting with the part 34 comprises a flat part 68 parallel to the wall 52, which communicates with the interior chamber 50.This wall also comprises a stepped section 70 comprising two steps, and a curved part 72 connected to the stepped part 70 along a ridge 74 forming a constriction with the flat part 52. This.

curved part 72 is opposite the curved, ridgeshaped section 56 of the part 32.

The relative position of the parts 32 and 34 may be adjusted to modify the distance between the ridge 74 and the ridge 56 by slightly shifting them in order thereby to give the flame the desired shape. Once this distance has been set, it suffices to maintain the parts 32 and 34 tightly together by way of the aboMe-mentioned fixing means.

It will be noted from Figs. 1 and 2 that at the side of the opening 58 the part 32 has a rounded front 76, whereas the part 34 has a straight front 78. The presence of the rounded front 76 is not indispensable, but forms a preferred embodiment which protects the flame emerging from the opening 58.

The rotating mixture of air and gas is accelerated in the converging passage 42 and subsequently enters the chamber 50 where the rotational movement of the mixture is changed into a lateral movement towards the diverging passage 54. The first part of this passage 54 which is situated between the wall 52 and the flat part 68 comprises a flat mixing chamber. This mixing chamber widens in the direction of the opening 58 as far as the stepped portion 20 designed to obtain the desired flows of the fuel mixture as well as homogenization of the latter.

This diverging passage passes the gaseous fuel mixture to the opening 58 while producing a flame adjustable according to the gas flow volumes. This flame is partly slowed down by the Coanda effect over the curved part 72 and stabilized by the turbulent movement produced by the ridge 56 and adjustable according to the shape of the flame to be obtained by sliding the parts 32 and 34 along the mating plane 36.

The burner according to the invention can be used alone or with other similar burners for the firing of products such as metal and glass products in open forging furnaces or in kilns for certain products. The burner can be placed in different positions and in different places in a furnace. It will be clear that the present invention is not limited to the above-described embodiment but that it is quite possible, without departing from the scope of the present invention, to devise various detail variants.

Thus it will be clear that the axis of the converging passage can be located differently in relation to the diverging passage and that the shape of the interior chamber cannot only be spherical but also ellipsoidal or of any similar rounded shape.

Claims

1. A burner designed to produce a wide flame, comprising a burner body for imparting rotation to a mixture of fuel gas and air and a burner head integral with the burner body, characterized in that the burner head comprises a generally spherical interior chamber connected to the burner body by means of a passage which converges in the direction of the chamber; and an elongated opening which can generate the flame, which is connected to the chamber by means of a passage which diverges in the direction of the opening, one large side of the opening comprising a first ridge and a curved section and the other large side of the opening comprising a second ridge.

2. A burner as claimed in claim 1, characterized in that the first ridge and the second ridge are displaced in relation to each other.

3. A burner as claimed in claims 1 and 2, characterized in that the diverging passage comprises two opposite parallel walls connected at the two large sides of the opening and that the converging passage has an axis of rotation normal to the two parallel walls opposite the diverging passage.

4. A burner as claimed in any one of claims 1-3, characterized in that the interior chamber is spherical.

5. A burner as claimed in claims 3 and 4, characterized in that the burner head is formed of two parts of which one comprises the converging passage, one of the parallel walls opposite the diverging passage and a spherical semi-dome forming one half of the interior chamber and the other part comprises the other parallel wall opposite the diverging passage, the two diverging walls of the diverging passage and a spherical semi-dome forming the other half of the interior chamber.

6. A burner as claimed in claim 5, characterized in that it comprises fixing means which can interconnect the two parts of the burner head so that they can be adjusted by sliding the two parts along a mating plane parallel to the parallel walls opposite the diverging passage.

7. A burner as claimed in claim 1, characterized in that the first ridge comprises a stepped section.

8. A burner as claimed in any one of claims 1-7, characterized in that the burner head is made of a refractory material.

9. A burner as claimed in any one of claims 1-7, characterized in that the burner head is made of a metal cooled by fluid circulation.