WO2025073826A1 - Crosslinking oven comprising an electric heating means arranged in the combustion chamber - Google Patents

Abstract

The present invention relates to an oven (2) for crosslinking a mat (16) of mineral and/or plant fibres, comprising at least one combustion chamber (4), at least one burner (14) configured to generate a flame inside the combustion chamber (4) and a crosslinking enclosure (6) which is configured to receive the mat (16) and is aeraulically connected to the combustion chamber (4), the oven (2) comprising at least one electric heating source (18) for heating the crosslinking enclosure (6), characterised in that the electric heating source (18) is arranged inside the combustion chamber (4).

Description

DESCRIPTION

Title of the invention: Crosslinking oven comprising an electric heating means arranged in the combustion chamber

The present invention relates to the field of crosslinking ovens and relates more particularly to the heating of mineral and/or vegetable fiber mattresses.

The crosslinking ovens for a mattress of mineral and/or vegetable fibers known to date comprise a heating system implemented by a gas burner. It is known to add to this study a second heating means such as an electric heating source, combined with the burner already included in the oven. In the prior art, this electric heating source is arranged specifically in the crosslinking box, in particular in a corner of the crosslinking box.

The current economic and ecological situation requires improving the efficiency of the heating methods used in these ovens, for example by reducing the heat input from the burner. Thus, the electrical heating source is configured to heat the mattress present in the reticulation box, which makes it possible to reduce the proportion of heating generated by the burner and consequently, gas consumption.

However, it is necessary to go further. The space available in the reticulation chamber does not allow for the integration of sufficient electric heating power in relation to the power requirements for cooking the mineral and/or plant fiber mat, and the quantity of gas consumed by the burner remains too high. Furthermore, the electric heating source located in a corner of the reticulation box tends to become clogged, which leads to a reduction in electric heating and a decrease in efficiency. In addition, this fouling requires downtime to clean the electric heating source. This downtime negatively impacts the manufacturing costs of the mineral and/or plant fiber mat.

The present invention solves these drawbacks and proposes an oven for crosslinking a mattress of mineral and/or vegetable fibers, comprising at least one combustion chamber, at least one burner configured to generate a flame within the combustion chamber and a crosslinking box aeraulically connected to the combustion chamber and configured to receive said mattress and, said oven comprising at least one electric heating source configured to heat the mattress, characterized in that the electric heating source is arranged in the combustion chamber.

The specific arrangement of the electrical heating source within the combustion chamber allows the installed nominal power of the burner to be reduced. The air flow does not have time to cool and remains at a high temperature until it comes into contact with the mattress circulating within the reticulation box.

According to another feature of the invention, the electrical heating source is arranged so as to be exposed to the flame generated by the burner. This arrangement makes it possible to destroy, for example by pyrolysis, any possible deposit or impurity present on the electrical heating source. This arrangement makes it possible to avoid losses in efficiency due to fouling of the electrical heating sources.

According to another characteristic of the invention, the oven comprises a hot air loop which comprises an outlet from the combustion chamber, a passage through the reticulation box and an inlet into the combustion chamber.

The air is heated in the combustion chamber via the burner and the electric heating source, the heated air then enters the crosslinking box. The hot air then transfers its calories to the mattress, which causes crosslinking of the glue that binds its fibers. The air in the hot air loop that leaves the crosslinking chamber is colder than when it enters it, and the burner and the electric heating source implement a new supply of calories to the hot air flow.

The glue that binds the fibers is generally known as a "binder."

According to another characteristic of the invention, the oven comprises at least one air circulation device configured to circulate hot air through the hot air loop.

The air circulation device may, for example, be a fan placed between the outlet of the combustion chamber and an inlet of the reticulation box.

According to another characteristic of the invention, the electrical heating source comprises at least one radiant tube resistor, said radiant tube extending transversely to a direction of the flow of hot air within the heating chamber. combustion. The radiant tube extends mainly along a first direction, while the air flow moves generally along a second direction, these two directions intersecting at a single point. The radiant tube of the resistance extends, for example, perpendicular to a direction of extension of the burner flame.

According to another characteristic of the invention, the electrical heating source comprises at least two radiant tubes aligned within the combustion chamber along the same axis. The axis on which the radiant tubes are aligned is perpendicular, or substantially perpendicular, to the direction of extension of the burner flame. According to a variant, in the combustion chamber, at least two radiant tubes are parallel and aligned on this axis, forming a pair of radiant tubes arranged along a common axis. The combustion chamber therefore has a minimum width allowing two radiant tubes to be placed end to end, along the same axis passing perpendicularly through the combustion chamber.

A succession of several radiant tubes is operated along different axes perpendicular to the combustion chamber.

According to another characteristic of the invention, the electrical heating source comprises at least two radiant tubes arranged within the combustion chamber along two separate axes.

The axes on which the radiant tubes are aligned are perpendicular to the direction of extension of the burner flame. A single radiant tube is placed on each axis. Several radiant tubes can be placed side by side, along parallel but distinct axes.

According to another characteristic of the invention, the combustion chamber comprises a first section where the burner is arranged and a second section where the electrical heating source is arranged, a volume of the first section being less than a volume of the second section.

The volume of the second section is greater than that of the first section in order to be able to place at least two radiant tubes end to end, aligned on the same axis. Limiting certain sections makes it possible to reduce the quantity of air to be heated and therefore the power to be used for heating.

According to another characteristic of the invention, the combustion chamber comprises a first section where the burner is arranged and a second section where the electric heating source, a volume of the first section being equal to a volume of the second section.

In this embodiment, the radiant tubes are arranged side by side, along a single row. The radiant tubes are inserted into the combustion chamber by a single face, or by two faces arranged opposite each other.

According to another characteristic of the invention, the combustion chamber is delimited by a peripheral wall which comprises at least one external frame, an internal peripheral sheet and a thermal insulator arranged between the two sheets.

The temperature of the external frame of the combustion chamber must be below 60 degrees Celsius (°C). The installation as envisaged here allows the nominal power of the burner to be reduced. For this reason, the structure of the peripheral wall of the combustion chamber can be a sandwich of sheets between which a thermal insulator is placed.

According to another characteristic of the invention, the nominal power of the electrical heating source is greater than or equal to the nominal power of the burner. Gas consumption can thus be reduced, compared to a prior art installation with equivalent total power.

The nominal power of the burner is, for example, 200 kW, while the nominal power of the electrical source is, for example, 220 kW. The system requires 220 kW/h in steady state. The total heat production of the oven is implemented at 50% for the electrical heating source and 50% for the burner. Alternatively, the distribution can be modified to reach 75% of the total heat production provided by the electrical heating source and 25% from the burner. We can therefore consider that the electrical heating source provides between 50% and 90% of the heating power required by the system.

The invention further relates to a method for manufacturing an insulation product comprising mineral and/or plant fibers bound by a binder, in particular an organic binder, the method comprising the following steps:

- supply of a mattress of mineral and/or vegetable fibers coated with a binder, in particular an organic binder, and

- heating of the mattress, the heating step being implemented by the oven of crosslinking as defined above, the mattress being housed in the crosslinking box of the crosslinking oven during heating.

According to another characteristic of the invention, the mass rate of binder in the insulation product is strictly greater than 0% and less than or equal to 20%, preferably greater than or equal to 2% and less than or equal to 10%, relative to the total mass of the insulation product.

According to another characteristic of the invention, the crosslinking oven comprises a hot air loop which comprises an outlet from the combustion chamber, a passage through the crosslinking box and an inlet into the combustion chamber, the mattress housed in the crosslinking box being heated during heating by a flow of hot air circulating in the hot air loop.

According to another characteristic of the invention, the flow of hot air is, for example, at a temperature greater than or equal to 100°C and less than or equal to 320°C, in particular greater than or equal to 220°C and less than or equal to 300°C, for example greater than or equal to 250°C and less than or equal to 300°C, for example equal to 260°C.

Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and from several examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawings on the other hand, in which:

[fig 1], figure 1 is a representation of a crosslinking oven comprising a combustion chamber composed of a burner and an electric heating source;

[fig 2], figure 2 is a sectional view of an embodiment of the combustion chamber of the oven according to the invention;

[fig 3], figure 3 is a sectional view of another embodiment of the combustion chamber of the oven according to the invention;

[fig 4], Figure 4 is a sectional view of a peripheral wall which surrounds the combustion chamber.

The features, variations and different embodiments of the invention may be combined with each other in various combinations, provided that they are not incompatible or mutually exclusive. In particular, it will be possible to imagine variants of the invention comprising only a selection of characteristics described below in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage and/or to differentiate the invention from the prior art.

The invention relates to a new oven and more particularly to a new combustion chamber of this oven making it possible to heat the crosslinking box by calories coming from a burner and by calories coming from an electric heating source, these two components being arranged inside the combustion chamber.

Figure 1 shows a crosslinking oven 2 according to the invention which comprises a combustion chamber 4, a crosslinking box 6 and a device 8 for circulating a flow of hot air.

In Figure 1, it can be seen that the combustion chamber 4 is located on the upper part of the crosslinking oven 2. More precisely, the combustion chamber 4 is located vertically above the crosslinking box 6. The combustion chamber 4 is aeraulically connected to the crosslinking box 6 on the one hand, by a first conduit 10 arranged between an outlet 11 of the combustion chamber 4 and an inlet 13 of the crosslinking box 6 and on the other hand, by a second conduit 12 which extends between an outlet 15 of the crosslinking box 6 and an inlet 17 of the combustion chamber 4. The combination of these conduits 10, 12, of the combustion chamber 4 and of the crosslinking box 6 forms a hot air loop where a flow of hot air circulates in a loop.

The curing oven 2 comprises a support 19 configured to support the combustion chamber 4. The support 19 extends above the curing box 6 and supports the weight of the combustion chamber 4.

The combustion chamber 4 comprises a burner 14 configured to generate a flame within the combustion chamber 4. Generally, the burner 14 is supplied by gas.

The combustion chamber 4 may comprise a device 8 for circulating hot air, such as a radial propeller fan 7 configured to implement circulation of the air flow within the hot air loop. The radial propeller 7 is configured to change the direction of the air flow within the hot air loop in order to pass from a horizontal direction in the combustion chamber 4 to a vertical direction in the first duct 10. The air circulation device 8 is connected on one side to a portion of the combustion chamber 4 and on the other the outlet 11 of the combustion chamber 4. The circulation device comprises an actuating device 9 such as a motor and a gearbox configured to actuate the rotation of the propeller 7 of the circulation device 8.

The crosslinking box 6 receives at least one mattress 16 of mineral and/or vegetable fibers, such a mattress 16 being intended to become a roll or a panel of glass wool, rock wool or a vegetable material used to thermally insulate any pipe, wall or more generally any object requiring thermal insulation.

The fiber mat(s) 16 are crossed by the hot air flow. The intake vent 13 of the crosslinking box 6 is arranged in the upper part of an enclosure which delimits the crosslinking box 6. The discharge vent 15 of the crosslinking box 6 is located in the lower part of this enclosure, on a face opposite that of the intake vent 13. The air flow thus follows a diagonal and downward path as it passes through the crosslinking box 6.

Figures 2 and 3 allow us to see that according to the invention, the combustion chamber 4 houses an electrical heating source 18, such as radiant tubes, for example inserted on either side of the combustion chamber 4.

The radiant tube is a metal cylinder comprising an inner surface and an outer surface. The outer surface of the radiant tube is in contact with the air flow of the hot air loop and this is the reason why the tube, or at least the outer surface of the tube, comprises or is covered with a material capable of resisting the corrosive nature of the burner flame. The inner surface is configured to be in contact with the air heated by a resistance included in the radiant tube. The radiant tube is airtight, the free end included in the combustion chamber 4 is closed. The radiant tube comprises a flange on the free end outside the combustion chamber 4. The radiant tube is made integral with the combustion chamber 4 via for example a removable mounting of the flange with the external sheet of the combustion chamber 4.

The radiant tubes arranged in the combustion chamber 4 are spaced apart from each other others in order to allow the air flow to pass through the combustion chamber 4 and exchange calories with the metal cylinders heated by the resistors.

The flame of the burner 14 is in contact with the radiant tubes. Thus, an extension direction 27 illustrating a projection of the flame of the burner 14, is secant, advantageously perpendicular, to an axis 20 of each of the radiant tubes.

Figure 2 is a longitudinal sectional view of one embodiment of the combustion chamber 4, the reticulation oven 2, the burner 14 and the circulation device 8. The burner 14 is arranged at a first end of the combustion chamber 4 so that its flame extends within the combustion chamber 4, along the extension direction 27. At the other end of the combustion chamber is the circulation device 8.

For example, thirty radiant tubes are arranged in the combustion chamber 4, organized in six rows of radiant tubes arranged in two blocks of three rows facing each other, each row comprising five radiant tubes arranged one above the other. The combination of these radiant tubes forms the electrical heating source 18. The tubes of a first block of radiant tubes are aligned with the tubes of a second block of tubes, along the axis 20 passing perpendicularly through the combustion chamber 4. The tubes of the blocks are thus aligned two by two, each pair sharing the same axis 20, the air flow licking each pair of radiant tubes aligned end to end.

The combustion chamber 4 comprises a first section 22 where the burner 14 is arranged at least in part, and a second section 24 where the electrical heating source 18 is arranged. It can be seen in this figure 2 that the second section 24 has dimensions greater than those of the first section 22. The volume of the first section 22 is thus less than the volume of the second section 24.

The first section 22 and the second section 24 are aligned along the extension direction 27.

The second section 24 is arranged vertically above the combustion chamber 4. The electrical heating source 18 is thus located vertically above the combustion chamber 4.

The combustion chamber 4 also comprises a divergent 21 which connects the first section 22 to the second section 24, this divergent being in the form of a tube conical. The combustion chamber 4 also comprises a convergent 23 which connects the second section 24 to the device 8 for circulating the hot air flow, this convergent being in the form of a conical channel.

Figure 3 is a longitudinal sectional view of another embodiment of the combustion chamber 4 of the crosslinking oven 2. The burner 14 is arranged at a first end of the combustion chamber 4 so that its flame extends within the combustion chamber 4, along the extension direction 27. At the other end of the combustion chamber 4 is the circulation device 8, the role of which is to ensure the circulation of the hot air flow within the hot air loop.

For example, thirty-two radiant tubes are arranged in the combustion chamber 4, organized into eight rows of radiant tubes arranged in a block, each row comprising four radiant tubes arranged one above the other. The combination of these radiant tubes forms the electrical heating source 18. Each radiant tube is aligned along a distinct axis 20 passing perpendicularly through the combustion chamber 4. The radiant tubes are thus aligned one by one, being arranged side by side, along distinct axes 20 but parallel to each other.

The second section 24 where the electric heating source 18 is arranged has dimensions greater than or equal to, or substantially equal to, those of the first section 22, in which the burner 14 is located.

Figure 4 is a sectional view illustrating a new type of thermal insulation of the combustion chamber 4, which is made possible by the arrangement of the electrical heating source 18 within the combustion chamber 4.

The insulation of the combustion chamber 4 comprises, for example, six layers: the first layer 26 is an internal peripheral sheet of the combustion chamber 4, which is here a steel or stainless steel coating. The choice of placing this sheet inside the combustion chamber 4 is advantageous because this sheet prevents any premature wear of the thermal insulation layer, which could result from the friction of the flow of hot air circulating within the hot air loop, or even from the flame as such. The second 28 and third 30 layers of the combustion chamber 4 are high-temperature microporous thermal insulators, for example 50 mm thick each.

The fourth 32 and fifth 34 layers comprise two different insulators between the side walls 36 and the upper and lower walls 38. The side walls 36 are rock wool panels. The upper and lower walls 38 are rigid mineral fiber panels. The fourth 32 and fifth 34 layers have a thickness of 50 mm. The sixth layer 40 is an external frame that surrounds and maintains the five layers previously described. The first layer 26 is the internal peripheral sheet that is closest to the flame generated by the burner 14, while the sixth layer 40 is the one closest to the external environment of the combustion chamber 4.

The invention further relates to a method for manufacturing an insulation product comprising mineral and/or plant fibers.

Such a product is, as previously indicated, a roll or panel of glass wool, rock wool or plant material used to thermally insulate any pipe, wall or more generally any object requiring thermal insulation.

The insulation product includes a binder.

The binder is, for example, an organic binder.

Thus, the mineral and/or plant fibers of the insulation product are bound by the binder.

For example, the insulation product has a binder mass rate strictly greater than 0% and less than or equal to 20%, in particular greater than or equal to 2% and less than or equal to 10%, relative to the total mass of the insulation product.

The method comprises a step of providing the mattress 16 of mineral and/or vegetable fibers coated with binder.

In this example, the binder is an organic binder.

The manufacturing method further comprises a step of heating the mattress 16. The heating step is carried out with the crosslinking oven 2.

During the heating step, the mattress 16 is housed in the crosslinking box 6 of the oven 2. Furthermore, during heating, the mattress 16 housed in the crosslinking box 6 is heated by the flow of hot air circulated in the oven 2.

The hot air flow is generated by the hot air circulation device 8.

The mattress 16 housed in the reticulation box 6 is crossed by the flow of hot air.

For example, the hot air flow is at a temperature greater than or equal to 100 degrees Celsius (°C) and less than or equal to 320°C, in particular greater than or equal to 220°C and less than or equal to 300°C, for example greater than or equal to 250°C and less than or equal to 300°C, for example equal to 260°C.

In the present example, the mattress 16 is heated to a temperature and for a duration allowing the hardening, in other words the crosslinking, of the binder.

Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention.

The invention, as just described, achieves the aim it set for itself, and makes it possible to propose a crosslinking oven which comprises at least two heating sources arranged in a combustion chamber, the two heating sources being at least one source of electrical energy and one source of energy resulting from combustion. Variants not described here could be implemented without departing from the context of the invention, provided that, in accordance with the invention, they comprise a combustion chamber comprising at least one resistor in accordance with the invention.

Claims

1- Oven for crosslinking (2) a mattress (16) of mineral and/or vegetable fibers, comprising at least one combustion chamber (4), at least one burner (14) configured to generate a flame within the combustion chamber (4) and a crosslinking box (6) aeraulically connected to the combustion chamber (4) and configured to receive said mattress (16), said oven (2) comprising at least one electrical heating source (18) for the mattress (16), characterized in that the electrical heating source (18) is arranged in the combustion chamber (4). 2- Crosslinking oven (2) according to the preceding claim, in which the electrical heating source (18) is arranged so as to be exposed to the flame generated by the burner (14). 3- Crosslinking oven (2) according to any one of the preceding claims, comprising a hot air loop which comprises an outlet (11) from the combustion chamber (4), a passage through the crosslinking box (6) and an inlet (17) into the combustion chamber (4). 4- Crosslinking oven (2) according to the preceding claim, comprising at least one air circulation device (8) configured to circulate hot air through the hot air loop. 5- Crosslinking oven (2) according to any one of the preceding claims, in which the electrical heating source (18) comprises at least one radiant tube resistor, said radiant tube extending transversely to a direction of the flow of hot air within the combustion chamber (4). 6- Crosslinking oven (2) according to any one of the preceding claims, in which the electrical heating source (18) comprises at least two radiant tubes aligned within the combustion chamber (4) along the same axis (20). 7- Crosslinking oven (2) according to any one of claims 1 to 5, in which the electrical heating source (18) comprises at least two radiant tubes arranged within the combustion chamber (4) along two separate axes (20). 8- Crosslinking oven (2) according to claim 6, in which the combustion chamber (4) comprises a first section (22) where the burner (14) is arranged and a second section (24) where the electric heating source (18) is arranged, a volume of the first section (22) being less than a volume of the second section (24). 9- Crosslinking oven according to claim 7, in which the combustion chamber comprises a first section (22) where the burner (14) is arranged and a second section (24) where the electric heating source (18) is arranged, a volume of the first section (22) being equal to a volume of the second section (24). 10- Crosslinking oven (2) according to any one of the preceding claims, in which the combustion chamber (4) is delimited by a peripheral wall which comprises at least one external frame (40), an internal peripheral sheet (26) and a thermal insulator (28, 30, 32) arranged between the two sheets (26, 34). 11- Crosslinking oven (2) according to any one of the preceding claims, in which a nominal power of the electrical heating source (18) is greater than or equal to a nominal power of the burner (14). 12- Process for manufacturing an insulation product comprising mineral and/or vegetable fibers bound by a binder, in particular an organic binder, the process comprising the following steps: - supply of a mattress (16) of mineral and/or vegetable fibers coated with a binder, in particular an organic binder, and - heating the mattress (16), the heating step being carried out by the crosslinking oven (2) according to any one of claims 1 to 11, the mattress (16) being housed in the crosslinking box (6) of the crosslinking oven (2) during heating. 13- Manufacturing method according to claim 12, in which the mass rate of binder in the insulation product is strictly greater than 0% and less than or equal to 20%, preferably greater than or equal to 2% and less than or equal to 10%, relative to the total mass of the insulation product. 14- Manufacturing method according to claim 12 or 13, wherein the crosslinking oven (2) comprises a hot air loop which comprises an outlet (11) from the combustion chamber (4), a passage through the crosslinking box (6) and an inlet (17) into the combustion chamber (4), the mattress (16) housed in the crosslinking box (6) being heated during heating by a flow of hot air circulating in the hot air loop, the flow of hot air being, for example, at a temperature greater than or equal to 100 degrees Celsius and less than or equal to 320 degrees Celsius.