EP0208600B1 - Assembly of stamped out parts for producing pulse combustion - Google Patents

Abstract

The assembly has at least one pulsating combustion chamber (2) acting as a principal chamber (6) and at least two lateral chambers (5). There is at least one flat tube exchanger part (3) and a combustion spur (4) between the chamber and the exchanger and the assembly is formed by two half shells which are welded together on the tubular exchanger plane. Each shell has a fixing at the level of the principal chamber to hold a separation plate while allowing it to move transversely.

Description

The present invention relates to a new chamber for pulsating combustion, said chamber having to allow the pulsating combustion of a mixture of fuel and oxidant.

The principle of pulsed combustion and its use for the realization of heating installations is known to those skilled in the art. It is in particular described in French patent 2,178,997 of April 2, 1973. In such installations, the main chamber is provided with a set of lateral chambers, with a transverse plate dividing the main chamber into two compartments such as the mixture of fuel and oxidizer which enters the first of these compartments, in the direction of the transverse plate, is divided by this plate and is forced, to pass behind it, to pass through the lateral chambers.

According to the particular embodiment described in the aforementioned patent, the main chamber has four lateral chambers, distributed around the axis connecting the inlet orifice to the outlet orifice and the transverse plate is fixed to the walls of the chamber. This set is made in one piece during foundry operations.

It is also expected that the plate and the chamber are joined together in several places, which should allow better heat transport to the wall of the main chamber. These fixing zones are distributed at the locations of the wall of the main chamber which are located between the lateral chambers.

It is also known from German patent DE-AI-3 337 048 a pulsed combustion heating system or the combustion chamber can be made in two parts welded together.

The separation into two compartments of the combustion chamber poses a problem, frequently encountered, which is that of differential expansion which may exist between the separation plate and the walls of the chamber since these elements can be brought to very different temperatures. In order to remedy these problems, it has been proposed in PCT patent application WO 81/00610 to provide the transverse plate with weakening zones situated along two perpendicular axes crossing at the center of the plate. In operation, and in particular during the combustion of the chamber, the plate is broken along these lines and therefore accepts dimensional variations due to temperature differences while continuing to play its role of separation plate.

To use these combustion chambers in complete boilers, all the elements are joined together by welding and brazing operations, which can cause certain problems during operation, in particular at the connection between the tubular exchanger and the horn which ensures the passage of burnt and hot gases between the chamber and the exchanger.

A first object of the invention is to provide a combustion chamber which allows a simple realization and which, once assembled, does not present sealing problems.

A second object of the invention is to provide a combustion chamber which also solves the problem of differential expansion between the plate and the chamber.

For this, the invention provides a new assembly for pulsating combustion comprising at least one pulsating combustion chamber in the form of a main chamber and at least two side chambers characterized in that it is constituted by at at least two shells shaped by stamping and connected together by welding, each of said shells comprising, at the level of the main chamber, fixing means constituted by stamped cavities in which a separation plate is adjusted with a minimum clearance allowing its transverse displacement .

According to a particular embodiment, said assembly also comprises at least part of a flat tubular exchanger and a connecting horn between said chamber and said part of the exchanger, it is then characterized in that it is produced in two shells which are assembled according to the general plan of the exchanger.

According to an additional characteristic of the invention, the assembly comprises the entire flat exchanger, this exchanger comprising a decoupling chamber into which open all the tubes of the tubular exchanger.

It is therefore understood that according to the invention it is possible to easily make a complete, monobloc assembly, by joining two stamped plates.

According to a preferred embodiment, these fixing means consist of cavities produced during stamping where the intermediate plate can be mounted.

In addition, according to a particular embodiment of the invention, the combustion chamber comprises four lateral chambers distributed around the main chamber, each lateral chamber being located in the immediate vicinity of two other chambers, so that each wall of a chamber is substantially in contact with a wall of a neighboring chamber, the contact zone of these two walls each defining a part of the wall of the central chamber, and the cavities are located in said parts of the wall of the main chamber.

• - la figure 1 est une vue en perspective d'une partie de l'ensemble réalisé selon l'invention,
• - la figure 2 est une vue de dessus de l'ensemble représenté figure 1 avant son assemblage,
• - la figure 3 est une demi-coupe de la figure 2 selon l'axe III,
• - la figure 4 est une vue de côté de l'ensemble représenté figure 1, - la figure 5 est une vue de face de l'ensemble,
• - la figure 6 et une coupe de la figure 5 selon l'axe VI.

Other characteristics and advantages of the invention will appear more clearly on reading the following description given in an illustrative and in no way limiting manner with reference to the appended drawings, in which

• FIG. 1 is a perspective view of part of the assembly produced according to the invention,
• FIG. 2 is a top view of the assembly shown in FIG. 1 before it is assembled,
• FIG. 3 is a half-section of FIG. 2 along the axis III,
• - Figure 4 is a side view of the assembly shown in Figure 1, - Figure 5 is a front view of the assembly,
• - Figure 6 and a section of Figure 5 along axis VI.

FIG. 1 shows an assembly (1) produced according to the invention. It comprises a combustion chamber (2), a flat tubular exchanger (3), of which only the upper part has been shown. The cham combustion flue (2) and the tubular exchanger are connected together by a horn (4) establishing a passage for the combustion gases.

The combustion chamber (2) has four lateral chambers, such as (5) and a central chamber (6) located between the inlet pipe (7) and the horn (4).

Figure 2 is a half top view of the chamber (2). Between the lateral chambers such as (5), (5a) and (5b), the upper walls (10) and (11) of the pinched areas are shown. As it appears better on the section of FIG. 3, each upper wall such as (10) and (11) is associated with a lower wall such as (12) and defines with it the housing (14) in which is housed the separation plate (13). The extension (14) has the shape of a cavity produced by stamping.

Each side chamber such as (5) and (5a) has side walls (51, 52, 53 and 54), or also (54a). The consecutive walls (53) and (54a) meet in the area (55) which partially defines the wall of the central chamber (6).

The housings such as (14) are located in the zone (55) and each extend between two consecutive walls (53 and 54a).

The plate (13) is adjusted so as to have a minimum clearance between its ends and the bottoms of the housings (14). According to the embodiment presented the contact between the plate and the housing (14) is almost linear but one could give any shape to the walls (10) and (12) which would allow a more or less extensive contact surface.

A firm fixing of the plate is thus obtained, but which allows transverse movements. For example, the plate can expand since under the effect of such expansion the walls (10) and (11) of the housings (14) will move apart.

To make the assembly shown in perspective in FIG. 1 and in front and side view in FIGS. 4 and 5, one starts with two stainless steel plates which are stamped according to the usual techniques to produce two half sets (18) and (19).

After placing the separation plate (13) inside a half-chamber by insertion into the cavities (14) and (14a), the plate (13) is immobilized in one of the cavities by making a point Welding. The two stamped half-assemblies are then joined and welded to the wheel over their entire length according to a strip (25) shown in figure (1

According to a variant, in the cylindrical upper part (26) corresponding to the inlet pipe (7), the tongue (25) is removed and the connection is made by a TIG (Tungsten Inert Gas) weld which makes it possible to reconstitute a perfect cylinder. and simplifies the connection of the assembly thus obtained with the other members of the boiler. The assembly produced is thus perfectly sealed.

During this operation, the exchanger (3) is advantageously produced, including a section along the axis VI. VI of Figure 5 is shown in Figure 6. The edges (20) and (21) are welded by the same weld bead T.I.G. (30). The two half-plates have been stamped so as to each define a series of half-tubes such as (31, 33) and (37, 34), each half-tube such as (31.37) being separated from the half-tube neighbor such as (33, 34) by a flat strip (35, 36). To seal the exchanger and prevent the tubes from communicating with each other, a seam weld is made on each flat strip.

However, according to the invention, it is advantageously still possible to produce an assembly comprising a complete exchanger constituted by the upper part (3), the central part (30), the lower part (31) and a decoupling chamber (32).

The decoupling chamber (32) consists of a cylindrical wall, a circular wall constituting a bottom and a connecting wall between the tubes and the interior of the chamber. It is perpendicular to the general plane of the exchanger.

The chamber is made like the rest of the assembly during the stamping of the half-plates and the bottom plate is attached and welded. It comprises a tube (50) for the outlet of the gases.

The advantage of such an embodiment is to have a continuous connection between the tubes and the chamber.

The central part (30) of the exchanger can have any shape and, for example, a shape could be provided such that the decoupling chamber is located below the chamber (5) and is not offset as shown in FIG. 4.

It is understood that one can use any other method of fixing the half-plates without departing from the scope of the invention. We can also make the assembly using more than two plates.

Claims (5)

1. Pulsatory combustion unit, comprising at least one pulsatory combustion chamber (2) taking the form of a main chamber (6) and at least two side chambers (5), characterized in that it is constituted by at least two shells formed by stamping and joined to each other by welding, each of the said shells comprising securing means (14) level with the main chamber (6), these securing means (14) constituted by stamped cavities into which is fitted a separation plate (13) with a minimum clearance allowing it to move transversally.

2. Pulsatory combustion unit according to claim 1, characterized in that it comprises at least one part of a flat tubular exchanger (3) and a linking horn (4) between the said chamber and the said exchanger, the said unit being made in two shell halves which are assembled according to the lay-out of the tubular exchanger.

3. Pulsatory combustion unit according to claim 1, comprising four side chambers distributed around the main chamber, each side chamber being situated between two other side chambers, each side wall of a side chamber being in obvious contact with a wall of a neighbouring chamber, each contact zone between these two walls defining a part of the wall of the main chamber, characterized in that the stamped cavities are situated in the said parts of the wall of the main chamber.

4. Pulsatory combustion unit according to claim 2, characterized in that it also comprises an uncoupling chamber linked to the part of the said exchanger which is opposite the part of it linked to the horn.

5. Pulsatory combustion unit according to claim 4, characterized in that the uncoupling chamber is cylindrical and closed by a circular wall.

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