BRPI0909265B1 - method for burning products in a ceramic oven, and ceramic oven - Google Patents

Abstract

A method for firing products (100) in a ceramic kiln (1 ), the kiln (1 ) comprising at least a flame burner (4), which is at least provided with a supply conduit (46, 6) of the comburent, an outflow conduit (43, 8) of the hot gases from the kiln, and a heat exchanger (40, 42) in order to operate a heat exchange between the fluid which flow through the supply conduit (46, 6) and the outflow conduit (43, 8). The method comprises cooling the products (100) by means of injection of a cooling fluid into the kiln, via the outflow conduit (43, 8) of the at least a burner (4), when the burner (4) is unignited.

Description

"METHOD FOR BURNING PRODUCTS IN A CERAMIC OVEN, AND CERAMIC OVEN" TECHNICAL FIELD The invention relates to a method for burning ceramic products as well as to a ceramic furnace capable of performing the method.

TECHNICAL BACKGROUNDS

As is well known, we went to ceramic products can be subdivided substantially into two general categories: we were tunnel type and we were intermittent.

We have been tunnel type, especially suited for burning ceramic tiles and tiles and, in short, comprise a long tunnel structure lined with refractory material, along which the products to be burned advance aboard automotive wagons or rotating support rollers. The tunnel is provided with heat regulation systems that allow the oven to be subdivided longitudinally into a plurality of successive sections at different temperatures, so that during advancement the ceramic products are subjected to all stages of the firing cycle. . The firing cycle comprises both more or less rapid heating and cooling stages and is generally represented by a diagram relating the temperatures of the various sections of the oven with their longitudinal positions within the oven.

In contrast, intermittent knots usually comprise a single firing chamber, enclosed by walls lined with refractory material, to which the products to be burned remain immobile.

We have been specially used for burning large and / or complex shaped products, possibly with walls of varying thickness, such as sanitary ware such as bathroom pedestals, sinks and bathtubs, but also kitchen utensils, insulators. ceramics for insulating ducts of high voltage power lines, or ceramic pipes for sewage conduits and the like. The intermittent shaft firing cycle is obtained via a progressive variation in the internal temperature in the individual firing chamber, and is thus represented in general by a diagram that relates the temperature of the oven to the time the products spend entirely on it.

In particular, the firing cycle typically comprises three successive stages, including a first uniform heating stage up to temperatures of about 1200 - 1300 ° C, an intermediate stage at a constant temperature, and a final cooling stage to resume the products. at room temperature. The cooling stage is divided into a first rapid cooling stage, during which products are rapidly brought to a temperature of about 600 ° C, followed by a slow cooling stage to room temperature. The slow cooling stage allows finished products to be free of defects and / or residual stresses, which can otherwise generate capillary cracks, larger cracks and sometimes real breakage. Proper regulation of the fast and slow cooling stages further allows the ceramic material to assume different chemical / physical structures on which the mechanical properties of the finished product depend. Temperature regulation in the firing chamber is generally achieved by a plurality of flameless burners, which are installed in suitable positions on the sidewalls and / or the dome walls and the bottom walls of the oven, from which they are located. facing directly into the firing chamber.

Each burner is associated with a fuel feed conduit, typically methane gas, and a oxidizer feed conduit, typically outside air at room temperature, that opens near the inner surface of the furnace wall to generate a freely developing flame in the firing chamber.

Relative valve devices are associated with supply conduits, whose valve devices regulate the flow of fuel and oxidizer, such as to regulate the flame intensity and thus the heat generated.

Unlike tunnel-type ones, where the overall duration of the firing cycle depends on the feed rate of the products in the oven, ie the time spent in the various sections of the oven, it is obvious that the overall duration of the firing cycle in a oven. The flashing time depends on how quickly the internal temperature in the individual burner chamber changes.

Intermittent ceramic weeds however have a very high level of thermal inertia that considerably affects the internal temperature gradient in the firing chamber.

In particular, thermal inertia has a negative effect, especially during the rapid cooling stages, during which ceramic products could be cooled faster than normally occurs without causing any defects in the final product, but lasting for a long time. greater reality than necessary, precisely because of the inevitable thermal inertia of the oven.

To solve this problem at least partially, air has been introduced into the oven through the burner supply ducts, such as to dissipate part of the internal heat by convection and cool ceramic products more quickly, reducing overall cycle life. Burning

This method however is not applicable to all types of intermittent ceramic kiln burners.

In particular, the prior art comprises flameless burners incorporating a heat exchanger, wherein the oxidizing air is preheated by an air flow and hot combustion fumes leaving the oven, the temperature of which basically coincides with the temperature in the chamber. Burning The hot gas flow moves along an outlet conduit provided in the burner body, whose outlet conduit opens in the oven and crosses the heat exchanger.

When the flame is lit, oxidizing air preheating allows for greater efficiency and overall oven performance, thereby reducing fuel consumption.

When the flame is extinguished, it is not possible to supply a suction cooling air from the feeder conduit of these burners, as it would otherwise be heated by the hot gases passing through the heat exchanger, and thus would reach the firing chamber at a very high temperature. to effectively cool the products contained therein and would generally increase the duration of the firing cycle.

Document D1: EP 0866296 shows an oven for ceramic products having transport means for the products to be treated. The products are treated within the heated internal volume of the furnace, heat being supplied by a plurality of suitable burners arranged above and below the ceramic products conveyor. Each burner has a deflector arranged along the flame path, so that the flame is diffused in a desired direction. In one embodiment described the deflector may be used to carry cold air.

Document D2: EP 1217299 shows an oven having the following page 4a minus two mutually opposite mixers of fuel and oxidizing air and which must be operated by alternatively activating two different modes of operation.

In a first operating mode, external air enters the system via a suitable line and, by means of a diverter, flows into a first mixer where it is supplied with fuel to heat the furnace. Part of the air exiting the furnace through an opposite mixer conduit is recirculated and returns into the oven, which is also used to heat the ceramic regenerator. The other part exits the system via a proper path.

In the second operating mode, external air enters the system and, via the same diverter and a suitable line, flows into the opposite mixer where it is fed with fuel to heat the oven. Part of the air that exits the stove through the conduit of the first mixer is recirculated and returns into the stove and it is also used to heat the ceramic regenerator. The other part exits the system.

DISCLOSURE OF INVENTION

An object of the present invention is to reduce the time required to complete the firing cycle in an intermittent ceramic furnace provided with such burners, in particular interfering with the rapid cooling time.

An additional object of the invention is to achieve the above objective with a simple, rational and relatively inexpensive solution.

These objectives are achieved by the features of the invention reported in the dependent claims. The dependent claims outline preferred and / or particularly advantageous aspects of the invention.

In particular, there is provided a device for burning products within a ceramic oven, wherein the oven comprises at least one burner provided with a oxidizer feed conduit, a hot gas outlet conduit from the oven, and a heat exchanger for promote heat exchange between the fluids flowing through the feed conduit and the outlet conduit. The method of the invention comprises cooling the products by introducing a coolant into the furnace through the outlet conduit of the at least one burner when the burner is switched off.

Thanks to the solution, the coolant flows through the outlet conduit in a countercurrent direction, that is, in a direction opposite to the normal direction of hot gases, preventing them from crossing the heat exchanger. The coolant thus reaches the firing chamber without undergoing any heat exchanger heating, thereby achieving rapid product cooling and an effective reduction in the overall firing cycle duration.

With respect to the terms "cooling fluid", general reference is made to any fluid that is at a lower temperature than the firing chamber. The method of the invention preferably includes the use of outdoor ambient air, for example at ambient temperature.

In a preferred aspect of the invention, during the cooling stage, the method also includes simultaneously supplying the oxidizer, i.e. normally an additional air stream at room temperature, through the extinguished burner feed conduit. The oxidizer will also not be subjected to any heat in the heat exchanger, as the heat exchanger will be crossed by two fluids that are substantially at the same temperature, and may reach the firing chamber at a lower temperature with respect to the cracking of the heat exchanger. oven, thus allowing efficient heat dispersion. Simultaneous supply of two streams further increases the overall flow of cooling fluid that is introduced into the ia chamber, thereby obtaining greater heat dissipation and cooling over that of the furnace.

This solution can be adopted at all stages where the cooling age has to be as high as possible, in particular during the rapid burning stages during which there is no risk of ceramic products remaining.

In a preferred embodiment of the furnace, the rater outlet conduit is associated with the valve device, which places the conduit in communication with the external environment, and can be activated as will eliminate communication with the outside in order to placing the outlet in communication with a special sealing fluid supply device, and vice versa.

In this context, during normal operation of the ion, the firing chamber is at a higher temperature than atmospheric fracture and the hot gases present therein flow from the outlet conduit, which is maintained in communication with the outside.

During the burner cooling stages, the valve device is activated such as to bring the outlet in communication with the supply fluid supply device, which forces the cooling fluid to flow into the outlet conduit go completely from the firing chamber.

In an alternative embodiment of the furnace, the reaming outlet conduit opens into the narrowed section of a venturi tube, which is neatly crossed by a control fluid, typically air outside the ambient temperature, which generates in the narrowed section a necessary depression. to draw in hot gases from the firing chamber.

In this context, the injection of coolant into the furnace is preferably carried out by diverting the control fluid within the outlet, countercurrent to the normal flow of gases between. This deviation can be achieved by simply preventing the axial flow of the venturi tube control fluid, for example, by closing a check valve located downstream of the venturi tube itself.

In this way, the control fluid is forced to flow from the nturi tube into the outlet conduit until it reaches the furnace firing chamber. The invention further provides a hermitable ceramic furnace capable of acting on the above-described burning method. The furnace comprises at least one flame burner, which is provided with at least one oxidizer feed conduit, a hot gas outlet manifold, and a heat exchanger designed to provide a heat exchange between the fluids flowing through. the feed conduit and outlet conduit; devices are provided for supplying the flow of a cooling fluid in the furnace through the burner outflow conduit, in a countercurrent direction to the normal outflow of hot gases.

As mentioned hereinbefore, the outgoing flow conduit is preferably associated with the valve device, which is intended to bring it into communication with the external environment, and is activatable as to eliminate communication with the outside by placing : output ripple in communication with the cooling air supply device, and vice versa.

Thanks to this solution, by activating the valve device and when the burner is turned off, the cooling fluid is forced by the positive supply to move countercurrent in the outlet conduit until it reaches the firing chamber.

In a different constructional embodiment, the burner outlet conduit opens in the narrow section of a venturi tube, which is inserted along an auxiliary conduit to be followed by a control liquid, such as to create in this narrow section, a pressure designed to draw hot furnace gases through the outlet conduit.

In this context, the cooling fluid supply device of the invention comprises device for diverting the fluid from the command to the outlet conduit, preferably sealed valve device to selectively close the auxiliary conduit downstream of the venturi tube.

Thanks to this solution, by closing the valve device, the control fluid is forced to flow through the outlet conduit: countercurrent until it reaches the firing chamber, where it cools the eramic products.

Additional features and advantages of the invention will arise from reading the following description provided by way of non-imitating example, with the help of the figures illustrated in the accompanying tables of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a sectional view of an intermittent ceramic oven of the invention.

Figures 2 and 3 illustrate a diagram of the plan of a furnace flameless jumper of Figure 1 in two stages of the firing process.

Figures 4 and 5 show a different plan diagram of the furnace flameless burner of Figure 1 in two stages of the firing process.

BEST MODE FOR CARRYING OUT THE INVENTION Intermittent ceramic furnace 1 comprises a single closed firing chamber 2, enclosed by refractory material walls, within which is located a fixed support structure 3 in which the ceramic products 100 to be burned are arranged. .

In the illustrated example, ceramic products 100 are sanitary ware such as for example bathroom pedestals, sinks and bathtubs, but oven 1 may also be used to burn other articles such as kitchen utensils, ceramic insulation for duct insulation. for high voltage power lines, or ceramic pipes for sewage conduits, and the like. Intermittent oven 1 may also be used to burn ceramic tiles or tiles, refractory tiles or other products.

The ceramic products 100 remain immobile in the intermittent furnace 1 throughout the firing cycle which is achieved by a programmed variation in the temperature in the firing chamber 2 as a function of the required times.

Numerous flameless burners 4 are properly mounted on the side walls of oven 1, whose burners 4 are intended to heat the firing chamber 2 as well as to regulate the temperature therein. A chimney 5 is located in the ceiling of the furnace 1, through which chimney 5 the hot combustion gases generated by the flames of the burners 4 are discharged outside.

In some applications, burners 4 may also be mounted on the ceiling and / or bottom wall of the oven 1.

As illustrated in FIGS. 2 and 3, each burner 4 comprises a substantially cylindrical outer jacket 40 which is inserted and locked integrally in a respective opening in the wall of the oven 1. The front end of the outer jacket 40 is opened towards the firing chamber 2 and is located aligned with the inner surface of the furnace wall while the rear end is closed and protrudes outwards.

An outlet mouth 41 is provided in the rear projecting tract of the jacket 40.

A cylindrical tube 42 is coaxially mounted within the outer jacket 40, the pipe 42 of which is smaller than the diameter of the outer jacket 40, such as to define with it an annular conduit 43 connecting the firing chamber 2 with the mouth. 41. The cylindrical tube 42 has a frustoconical front tract, one end of which projects slightly beyond the edge of the outer jacket 40, and is opened toward the inside of the firing chamber 2. The opposite end of the tube cylindrical 42 is closed, and projects posteriorly to the outer jacket 40 containing it.

An inlet mouth 44 is provided in the protruding tract of the cylindrical tube 42.

A central tube 45 is coaxially coupled to the cylindrical tube 42, whose central tube 45 has a smaller diameter than the cylindrical tube 42, such as to define with it an annular conduit 46 which places the inlet mouth 44 in communication with the firing chamber 2. The central tube 45 extends from the bottom of the cylindrical tube 42 to the frustoconical tract, where it is closed by a transverse plate 47.

A central inlet opening 48 is provided at the bottom of the cylindrical tube 42, while an outlet opening 49 is provided in the center of the transverse plate 47, whose outlet opening 49 places the central tube 45 in communication with the frustoconical tract of the cylindrical tube 42. and thus the firing chamber 2. In this way, the central tube 45 defines a conduit that connects the inlet opening 48 with the firing chamber 2.

In the embodiment illustrated in FIGS. 2 and 3, the inlet nozzle 44 is connected to a combustion air supply line 6 which is collected outside at room temperature via a compressed compressor 61 forcing the internal pressure into it. annular conduit 46 and thence toward burner 2. Inlet port 48 is connected to a fuel line 7, typically methane gas. Supply line 7 is intercepted by a pneumatically controlled ion regulator 70, which is automatically piloted by the oxidizing air sound in supply line 6, and is calibrated to provide correct fuel flow as a function of air flow. .

Finally, outlet 41 is connected to a line of: arga 8, which opens directly into the external environment through a niné (not shown). The discharge line 8 is intercepted by a first valve which is activatable such as to selectively open and close the discharge line 8 connection with the external environment. The discharge line 8 is in communication between the mouth of 41 and the first valve 85 with the supply line 6 via a conduit 86. The auxiliary conduit 86 is intercepted by a second valve which is openable. and selectively closing communication 2 supply line 6 and discharge line 8. The product 100 firing cycle in the intermittent furnace 1 in 1 comprises a heating stage, during which the burners: are normally lit, a flashing stage. maintenance at a moving temperature, and a subsequent cooling stage to return the products to atmospheric pressure, during which burners 4 are extinct.

As mentioned in the preamble here, the wailing stage is divided into an early rapid cooling stage, during which the temperature of the products 100 is rapidly lowered to about 00 ° C, followed by a slow cooling stage to 250-300 ° C. , after which a new rapid cooling stage begins, down to ambient temperature.

As illustrated in Figure 2, when the burners 4 are ceased, the second valve 87 is closed and the oxidizing air is supplied by the compressor 61 via the supply line 6 within the annular conduit 46 where it moves toward the frustoconical tract of cylindrical tube 42 that is trapped inside the firing chamber 2. Fuel is regulated by the flow regulator 70 and drawn via the supply line 7 into the central tube 45, where it drains toward the outlet opening 49 provided on the transverse plate 7.

In this way, the fuel and the oxidizing air mix with the frustoconical tract of the cylindrical tube 42, where they ignite a vre flame that develops inside the firing chamber 2.

On the transverse plate 47, special lighting devices installed there, not illustrated here, as they are of the known type, which allow the flame to be lit to light the burner 4.

During the heating stages with the flame lit, the first valve 85 of the discharge line 8 is open. The pressure of the hot flue gas within the chamber 2 is slightly greater than atmospheric pressure, so that a stream of these gases flows through the annular conduit 43 of the opener end 4 of the cylindrical liner 40 toward the mouth and exit 41, and from there it flows into the discharge line 8 out of the chimney.

During the intersection of annular conduit 43, hot gases randomly collide in the side wall of cylindrical tube 42 into which the combustion air flows countercurrently. The wall of the cylindrical tube 42 is made of a good thermally conductive material, typically a metal or more preferably carborundum, allowing the transfer of thermal energy between the hot gases from the firing chamber 2 and the combustion air from outside. The outer jacket 40 and the cylindrical tube 42 are in practice a countercurrent heat exchanger. In order to improve the efficiency of the exchanger, the sidewall of the cylindrical tube 42 may be finned to increase heat exchange.

The hot gases are at substantially the same temperature as the firing chamber 2, such that the oxidizing air heats up before mixing with the fuel, improving the efficiency and overall performance of the intermittent furnace 1 and thereby reducing fuel consumption.

Hot gases leaving furnace 1 via the discharge line 8 and / or the chimney 5 may be supplied entirely from a second intermittent ceramic furnace (not shown), unlike one described herein, thus obtaining a greater exploitation of the heat of the gases and overall energy savings.

As illustrated in Figure 3, to cool the products 100, the fuel flow from the supply line 7 is interrupted, such as to cause the flame of the burner 4 to go out. The compressor 61 of the supply line 6 thus continues to introduce oxidizing air into the furnace chamber 2. Oxidising air is at room temperature such that a portion of the heat present in the inner chamber 2 dissipates by convection, operating a gentle cooling action on ceramic products 100. Oxidising air effectively acts as a cooling fluid during this stage. In order to accelerate cooling of the products 100, the first valve 85 of the discharge line 8 is closed such as to eliminate communication with the outside and at the same time the second valve 87 is opened as such. placing discharge line 8 in communication with supply line 6 downstream of compressor 61.

In this way, the air pumped by the compressor 61 also flows backwards along the discharge line 8, enters the burner 4 and flows through the annular conduit 43 of the outlet mouth 41 towards the firing chamber 2. The air flow prevents the hot gas outflow from the firing chamber 2 and thus impairs the operation of the heat exchanger defined by the outer jacket 40 and the cylindrical tube 42.

For this reason, the air at room temperature that is pumped by the compressor 61 is not subjected to any heat in the heat exchanger and, when it opens in oven 1, dissipates a greater amount of heat, obtaining faster cooling of the ceramic products. 100 and thus a generally shorter duration of the firing cycle.

This solution can be effectively adopted at all stages where the cooling speed of products 100 should be as high as possible, particularly in the early stage of rapid cooling. It is obviously possible to increase the speed of compressor 61 in order to increase the flow of cooling air that is introduced into the oven chamber 2.

The stages described are preferably controlled by programmable control devices, which can automatically control not only valve groups 85 and 87, but also the fuel supply device and all other operating organs involved in furnace operation 1.

In the alternative embodiment illustrated in FIGS. 4 and 5, the inlet 44 is connected to an oxidizing air supply line 6 which is directly collected outside at room temperature via a compressor not shown. Supply line 6 is intercepted by an automatically activated valve group 60, which allows supply line 6 to be opened and closed, and to regulate the oxidizing air flow that is supplied to burner 4. Input port 48 is connected. to a fuel supply line 7 which, as in the previous embodiment, comprises a pneumatically controlled flow regulator 70, automatically piloted by the oxidizing air pressure in the supply line 6. The outlet port 41 is finally connected to a discharge line. 8, which opens in the narrow section of a venturi tube 80. The venturi tube 80 is inserted axially along an auxiliary line 81 in which a pressurized control fluid flows, preferably an air stream which is directly collected from outside at room temperature. .

Flowing axially from inlet 82 to outlet 83 of venturi tube 80, the control fluid creates a depression in the narrow section that allows hot gases in the firing chamber 2 to be drawn through annular conduit 43 from outlet port 41 and downstream 8. Downstream of venturi 80 with respect to the direction of flow of control fluid, auxiliary line 81 is intercepted by an automatically activated valve group 84, which allows auxiliary line 81 to be opened and closed. .

As illustrated in Figure 4, when burners 4 are lit, valve group 60 is opened and oxidizing air is supplied via supply line 6 into annular conduit 46 where it flows toward the frustoconical tract of cylindrical tube 42 opening inside the firing chamber 2.

Similarly to the previous case, the fuel is regulated by the flow regulator 70 and supplied via the supply line 7 within the central tube 45, where it flows towards the outlet opening 49 provided on the transverse plate 47.

In this way, the fuel and the oxidizing air mix in the frustoconical tract of the cylindrical tube 42, where they light a free flame that develops internally in the firing chamber 2.

During the heating stages with the flame lit, the valve group 84 is opened and the control fluid flows into the auxiliary line 81, which creates the aforementioned depression in the narrow section of the venturi tube 80. This depression draws in part of the hot combustion gases present in the firing chamber 2, which flows through the annular conduit 43 of the burner 4 of the open end of the cylindrical jacket 40 towards the outlet mouth 41.

Hot gases flow from the outlet mouth 41 to the discharge line 8 until they mix with the control fluid in the venturi tube 80, such as to flow through the upstream tract of the auxiliary line 81, to the opening to outside through a chimney (not shown).

During the crossing of annular conduit 43, the heat energy of the hot gases from the firing chamber 2 is transferred at least in part to the combustion air from outside, thanks to the outer jacket 40 and the cylindrical tube 42, which function as a countercurrent heat exchanger.

In this case also, hot gases flowing out of the discharge line 8 and / or the chimney 5 may be supplied to a second ceramic furnace, distinct from one described herein, such as in order to heat it faster and / or preheat the oxidizer supplied to your burners for overall energy savings.

As illustrated in Figure 5, in order to resine the products 100, the fuel flow from the supply line 7 is interrupted, such as to cause the burner flame to extinguish.

At the same time, the valve group 84 is activated such as to close the auxiliary line 81 downstream of the venturi tube 80 such that the control fluid does not flow freely towards the chimney.

In this way, the control fluid cannot flow axially from the venturi tube 80 and is therefore forced to flow backwards along the discharge line 8, enter the burner 4 and flow along the annular conduit 43 of the outlet mouth 41 towards the firing chamber 2. The flow of the control fluid prevents the flow of hot gases from the firing chamber 2, and thus prevents the operation of the heat exchanger which is defined by the outer jacket 40 and the cylindrical tube 42.

For this reason, the control fluid, which, as mentioned above, is normally air at room temperature, is not heated in the heat exchanger and, when it opens in oven 1, dissipates part of the heat in the heating chamber by convection. firing 2, achieving faster cooling of ceramic products 100 and thus a shorter overall firing cycle duration.

While the control fluid is fully supplied by the firing chamber 2, the oxidizer can be dispensed into the furnace 1 via the supply line 6, leaving the valve group 60 open.

In this way, the simultaneous supply of two air currents increases the overall flow of cooling gas that is injected into the firing chamber 2, thereby achieving greater heat dissipation and thus faster furnace cooling.

This solution can be adopted at all stages where the cooling rate of 100 products can be as high as possible without the risk of damage, particularly during the rapid cooling stage of ceramic products 100.

However, during slow cooling stages, valve group 60 may be closed in such a way that products are cooled only by the control fluid. Preferably, the firing stages described hereinbefore are controlled by programmable control devices, which can automatically control not only valve group 60 and 84, but also the fuel supply device and all other operating organs involved in furnace operation. 1.

Of course, those skilled in the art can make numerous technical-application modifications to the intermittent oven 1 and the method of burning the products 100 as described without departing from the scope of the invention as defined in the claims.

Claims (10)

1. Method for burning products (100) in a ceramic furnace (i), the furnace (1) comprising at least one flame burner (4), which is provided with at least one nburent feed conduit (46, 6), a conduit outlet (43, 8) of the furnace hot gases, and a heat collector (40.42) to provide a heat exchange between the fluid and flow through the feed conduit (46, 6) and the heat conduit. 1, 8), characterized in that the method comprises cooling the ducts (100) by injecting a cooling fluid into the furnace via the outlet conduit (43, 8) of the at least one burner (4) when the burner (4) is deleted. Method according to Claim 1, characterized in that, during the injection phase of the coolant, the anode comprises simultaneously supplying the furnace with oxidizer via the feed nipple (46,6) of the minus one burner out (4). Method according to Claim 1, characterized in that the outlet conduit (43, 8) is associated with the Ivula device (85, 87) for placing the outlet conduit (43, 8). ) ethically in communication with the external environment or with a supply device (61) supplying a coolant, and wherein the coolant injection stage is obtained by activating the Ivula device (85, 87) such as to place the output conduit (43, 8) in communication with the supply device (61). Method according to claim 3, characterized in that activation of the valve device (85, 87) places the output idit (43, 48) in communication with supply device L) which is additionally intended for supply the oxidizer to the ment conduit (46, 6), the cooling fluid and the oxidizer being the same gone. Method according to claim 1, characterized in that the outlet conduit (43, 8) of the burner (4) opens in the restricted section of a venturi tube (80) which is axially flowed through a control fluid, which creates in the narrow section a depression for sucking in the hot gases from the furnace (1), the coolant injection stage being obtained by diverting the control fluid from within the burner outlet conduit (43, 8) (4). Method according to claim 5, characterized in that the deflection of the control fluid is obtained by preventing the control fluid from flowing axially out of the venturi tube (80). A ceramic furnace comprising at least one flame burner (4) which is provided with at least one oxidizer feed conduit (46, 6), a hot gas exhaust conduit (43, 8), and a heat exchanger. 40,42 to promote a heat exchange between the fluid flowing through the feed conduit 46,6 and the outlet conduit 43,8, wherein it comprises device 61,80, 84) for supplying a cooling fluid to the flue via the outlet conduit (43, 8) of at least one burner (4), characterized in that the outlet conduit (43, 8) is associated with the valve device (85, 87) that is intended to place the outlet conduit (43, 8) selectively in communication with the external environment or device (61) to supply the cooling fluid. A compound according to claim 7, characterized in that the device (61) for supplying the cooling fluid is additionally intended for supplying the oxidizer in the supply conduit (46,6), the cooling fluid and the oxidizing being the same fluid. A plug according to claim 7, characterized in that the outlet conduit (43, 8) opens in the narrow section of a venturi tube (80) which is inserted along an auxiliary conduit (81). ) intended to be drained by a control fluid, such as in order to create a pressure in the narrow section to draw in hot furnace gases, the> coolant supply means comprising> a device for diverting the control fluid from inside the outlet conduit 3). A method according to claim 9, characterized in that the bypass device (84) comprises a valve device for selectively closing the auxiliary conduit (81) downstream of the venturi (80).