EP0509882B1 - Linear burner - Google Patents

Abstract

The invention relates to a linear burner with jets extending through an opening made in a wall of a body of the burner defining an air-distribution chamber. According to the invention, the jets are connected to a series of tubes for supplying fuel gas or a gas/air mixture, these tubes passing through the body of the burner in order to be connected on the outside to a distribution housing provided with gas or with a gas/air mixture, this housing comprising adjustment means for selectively supplying the tubes joined to the jets.

Description

The invention relates to a linear burner supplied with combustible gas and combustion air.

In the art, such a burner is also called a ramp burner.

An example of a burner of this type can be found in patent application FR 2 641 601.

It is a burner comprising at least one row of injectors, each injector extending through an opening in a wall of a body of the burner internally forming an air distribution chamber with which said injectors communicate, these injectors being arranged substantially perpendicular to a longitudinal direction in which the body of this burner extends.

This type of burner has the advantage of offering a very wide range of heating power.

Its use is widespread especially in the food industry.

It allows a good distribution of the heating zone as well, a priori, as a possible relatively precise adjustment of the power, taking into account the multiplication of the injectors and their distribution.

To favor the variation of the active width of the burner, that is to say adapt to the heating needs the number of injectors having to operate, the aforementioned publication FR 2 641 601 proposes to mechanically vary the volume of the burner body, so as to connect to the supplies provided for this purpose a more or less large number of injectors.

Such a mechanical adjustment by moving parts nevertheless has certain drawbacks linked in particular to problems of sealing and possibly of mechanical strength of the drive parts, the pistons provided for this purpose being able in particular to become blocked.

In addition, on the burner in question, it may be difficult to know the useful volume released from the burner body and therefore the available heating power. In addition, under certain conditions, flame instability could appear, the pressure drops being unevenly distributed inside the body.

It will also be noted that such an apparatus requires the production of an assembly comprising a large number of parts and in particular the presence not only of an air distribution chamber, but also, arranged inside, of a chamber fuel gas distribution system, the injectors then being supplied "globally" via this second chamber.

The object of the invention is in particular to solve the above-mentioned difficulties, by proposing a burner devoid, on the body of the burner, of a gas distribution chamber and of mechanical members for controlling the number of injectors to be supplied, allowing thus improving the general operation and reliability of the system by reducing manufacturing costs.

More specifically, the burner of the invention is characterized in that the injectors with which it is provided are connected individually, or in groups, to a series of fuel gas supply tubes, or to a mixture of combustible gas and air, these tubes passing through the body of the burner to connect externally to a distribution box itself connected to a main supply pipe in which circulates combustible gas or a mixture of combustible gas and air, this housing comprising adjustment means for selectively supplying, in whole or in part, said supply tubes connected to the injectors.

Thus, the burner body, that is to say its frame, contains only one air distribution chamber, without a combustible gas distribution chamber.

Advantageously, this burner body may also be in the form of a duct or channel of substantially rectangular or square section in which a slot will be formed extending in the longitudinal direction of the body and through which the injectors will protrude.

According to another characteristic of the invention, the adjustment means available to the distribution box adjoining the burner body may consist of metering means for measuring the supply of combustible gas or gas / air mixture to at least some of the injectors.

For the production of the adjustment means, among others that could be envisaged, two were more particularly retained, namely a solenoid valve system and a sliding sector system making it possible to close off or uncover a series of orifices connected to the tubes. injector supply.

Of course, both for compactness and reliability, without excess cost, the arrangement of the distribution box next to the burner body to which the box will be fixed by a flange appeared as a completely favorable solution.

• la figure 1 est une vue schématique d'un premier mode de réalisation d'un brûleur linéaire conforme à l'invention,
• la figure 2 est une vue en coupe dans le sens de la ligne II-II de la figure 1,
• la figure 3 est une vue également schématique en perspective d'une variante de réalisation du brûleur de la figure 1,
• la figure 4 est une vue schématique illustrant le principe de fonctionnement du moyen de réglage utilisé sur le brûleur de la figure 3 pour l'alimentation sélective des tubes d'alimentation reliés aux injecteurs,
• et la figure 5 est une vue locale en coupe transversale longitudinale d'une réalisation techniquement possible du brûleur illustré schématiquement sur la figure 3.

Other characteristics and advantages of the invention will also appear from the description which follows, given with reference to the appended drawings given by way of nonlimiting examples, and in which:

• FIG. 1 is a schematic view of a first embodiment of a linear burner according to the invention,
• FIG. 2 is a sectional view in the direction of line II-II of FIG. 1,
• FIG. 3 is also a schematic perspective view of an alternative embodiment of the burner of FIG. 1,
• FIG. 4 is a schematic view illustrating the operating principle of the adjustment means used on the burner of FIG. 3 for the selective supply of the supply tubes connected to the injectors,
• and FIG. 5 is a local view in longitudinal cross-section of a technically possible embodiment of the burner illustrated diagrammatically in FIG. 3.

In FIG. 1 first of all, a linear burner 1 is thus seen illustrated according to the invention, comprising an elongated or constructed body 3 internally defining an air distribution chamber 4 intended to supply air (primary or secondary) a series of injectors shown diagrammatically in 5, themselves supplied with combustible gas or with a combustible gas / air mixture by a network of tubes 7a, 7b, 7c ... connected, outside the body 3, to means adjustment identified as a whole 9 and intended to selectively supply, in whole or in part, said injector supply tubes.

The adjustment means 9 are housed in a distribution box 11 laterally attached to the body 3 and shown in phantom lines.

Conventionally, the injectors 5 are distributed in rows forming in this case a single row or line extending in the longitudinal direction 3a of the body 3.

As illustrated, the body 3 in question may advantageously be in the form of a metal conduit or channel of substantially rectangular or square section with a longitudinal slot 12 provided for the passage of the injectors and their adaptation to the body, the interior volume 4 of this body being adapted to form a suitable "air box".

Depending on the type of supply selected, the body 3 can either be open at its opposite longitudinal ends (see FIG. 3) for an air supply atmospheric, either closed at said ends and then connected to a supply air supply line (pressurized air) shown diagrammatically at 16 in FIGS. 1 and 5 and opening into volume 4. In either case, the injectors will of course communicate, in a conventional manner, with this interior volume 4 by a peripheral air passage 18 formed at the level of the slot 12, inside an air injection cone or ring 20 surrounding each injector (see in particular Figures 2 and 5).

As can be seen more clearly in FIG. 2, these injectors are here fixed transversely inside the body 3 by flanges 13, 15 and fixing screws 17, so as to pass through an upper wall 3b of this body, through the long slot 12 formed in the direction of the longitudinal direction 3a of the body.

In this FIG. 2, it will be noted that the illustrated injector is connected, inside the body, to one of the supply tubes marked 7a, the other injectors in the row being them, either connected individually to other identical supply tubes 7b, 7c ... joined together in sheet 19, or connected in group to a supply tube of larger diameter such as 7d, the connection principle adopted being a function of the field of application of the burner and of the degree of adjustment of the desired power of the injectors taken independently or in small groups. In FIG. 1, it will moreover be noted on this subject that if the first and fourth injectors are supplied individually by the tubes 7b and 7c, the second and third are on the other hand supplied jointly by the tubes 7a and 7b. (In FIG. 3, another feeding principle has also been envisaged).

Inside the housing 11, the tubes 7a, 7b, etc. are themselves connected to a general fuel gas supply duct or a fuel gas / air mixture 21.

As illustrated in FIGS. 1, 3 and 5, the distribution box 11 will preferably be fixed laterally to a longitudinal end of the body 3, via a fixing flange 23 in which a passage 25 has been provided for the supply pipes 7a , 7b ... (see Figure 5).

The adjustment means 9, the role of which, as has been said, is to allow, from outside the burner body, to selectively supply all or part of the supply tubes connected to the injectors, may have various shapes. It is however advisable to choose means allowing the dosing of the fuel gas supply or gas / air mixture of at least some of these injectors.

Two exemplary embodiments have been shown in the figures.

In FIG. 1 first of all, these means consist of a series of solenoid valves 24 interposed inside the volume of the housing 11 on each supply tube 7a, 7b ..., downstream of their common connection to the general conduct 21.

These solenoid valves can of course be connected to any usual command and control system, in particular via an electronic automatic control unit (not shown).

In FIGS. 3 to 5, the adjustment means in question have been replaced by a sliding sector system comprising a fixed part 27 in the thickness of which are locally formed orifices 29 in number at least equal to the number of tubes supply 7a, 7b ... to which these orifices are connected on one side, communicating, on the other side, with the general supply line 21, via a distribution chamber 31 (see FIG. 5).

In contact with and opposite the fixed part 27 slides, for example in rotation, a moving part 33 having through its entire thickness a slot 35 (see Figures 3 and 4) such that it can cover in a gas-tight manner, or uncover, all or part of the orifices 29 of the fixed part 27, by displacement of the movable part .

As can be seen more clearly in FIGS. 3 and 4, this movable part 33 may be in the form of a rotary sector having a slot 35 in an arc of a circle, the orifices 29 of the fixed part 27 then being in correspondence , also arranged in an arc.

In FIG. 5, it will further be noted that there is a control linkage 37 that can be actuated from outside the housing to act on the moving part 33, via a plate 39.

Claims (8)

1. Linear burner comprising at least one row of injectors (5), each injector extending through an opening (12) provided in a wall of a burner body (3) internally forming an air distribution chamber (4) with which the injectors communicate, characterised in that the injectors (5) are connected individually or in groups to a series of tubes (7a, 7b, etc) for supplying combustible gas or a mixture of combustible gas and air, these tubes passing through the burner body (3) and being connected externally to a distribution casing (11) itself connected to a main supply conduit (21) in which the combustible gas or a mixture of combustible gas and air circulates, this casing comprising regulating means (9) for supplying selectively all or some of the supply tubes (7a, 7b, etc) connected to the injectors.
2. Burner according to Claim 1,
   characterised in that the regulating means (9) of the distribution casing (11) consist of metering means for metering the supply of combustible gas or mixture of combustible gas and air to at least some of the injectors (5).
3. Burner according to Claim 1 or 2,
   characterised in that the body (3) of the burner is in the form of a conduit or duct having a substantially rectangular or square cross-section in which is provided a slot (12) which extends in the longitudinal direction (3a) of the body and through which the injectors pass.
4. Burner according to any one of Claims 1 to 3, characterised in that the tubes (7a, 7b, etc) for supplying the injectors (5) with combustible gas or with a mixture of combustible gas and air are grouped in a layer/layers (19) inside the burner body (3).
5. Burner according to any one of the preceding claims, characterised in that the regulating means (9) comprise:

   - a fixed part (27) perforated by at least as many apertures (29) as there are supply tubes (7a, 7b, etc) connected to the injectors (5), these apertures communicating with the general supply conduit (21); and

   - a movable part (33) having a slot (35) passing through this part such that it can cover in a gastight manner or uncover all or some of the apertures (29) in the fixed part by displacement of this movable part.
6. Burner according to Claim 5,
   characterised in that the movable part (33) is in the form of a rotating segment which can be controlled by a control means (37) from the exterior of the casing (11), the apertures (29) in the fixed part (27) being accordingly arranged in the manner of an arc.
7. Burner according to either of Claims 1 and 4, characterised in that the regulating means (9) comprise electrovalves (24).
8. Burner according to any one of the preceding claims, characterised in that the distribution casing (11) is disposed adjacent the burner body (3) to which it is secured in the extension of a longitudinal end thereof.

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