JPH03225105A - surface combustion burner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a two-layer structure surface combustion burner constructed by bonding a flame-resistant material layer and a metal fiber mat layer, and particularly a method for bonding the two layers. Regarding.

[Conventional technology] Infrared heating equipment is expected to be applied in a wide range of fields such as food cooking, heating, and drying of painted objects. Surface combustion is one of the technologies that uses inexpensive, high-calorie gas fuel as the heat source. There's a burner.

Surface combustion burners efficiently convert the thermal energy of combustion gas, which is mostly carried away by convection in normal combustion, into radiant heat. By supplying a premixed gas fuel and burning it in the surface layer on the other side, the surface layer of the burner plate itself is heated, causing it to emit radiant heat. Therefore, in a surface combustion burner, gas combustion is maintained with the flame in close contact with the surface of the burner plate or penetrating into the surface layer, and radiant heat is radiated from the flame and the burner plate surface layer heated to a red-hot state. Ru.

Surface combustion burners that use sintered metal plates or sintered ceramic plates as the burner plate material have already been put into practical use in several fields such as cooking utensils. Products using sintered fiber mats are also being actively researched. These surface combustion burners have the advantage of not only being able to obtain radiant heat with high efficiency, but also being able to achieve stable combustion that is not affected by the external environment such as wind or temperature. The burner plate made of C (hereinafter referred to as SOS mat) can be shaped into a complex surface shape, has good strength, and if a material with high porosity is selected, it has a large area, low pressure drop, high burnup, and high Since it is easy to manufacture products with a high power density and is relatively inexpensive, it is expected to be applied to, for example, heating devices at outdoor work sites, and baking and drying of automobile paint.

FIG. 3 is a schematic diagram showing the structure of an infrared heater used at an outdoor work site, which is an example of a surface combustion burner using a burner plate made of SOS mat, and a section including the burner plate is shown.

In Fig. 3, the burner plate m has a diameter of 20 μm and a length of 50 μm.
It is composed of a 5mm thick SUS mat made by forming long fibers of 5US316 into a mat shape and sintering them together.During operation, the surface layer m1, gas combustion area, and radiant heat release area are It becomes.

Here, a gas supply system including a gas nozzle GN, a solenoid valve Sv, a fuel gas head T, and an air supply system including a blower F are connected to the burner body K to which the burner plate m is attached. Further, a spark electrode S for ignition is provided opposite the lower end of the burner plate m, and by operating the switch, the control device C operates the solenoid valve SV and the blower F, and also operates the spark electrode S. A spike-like high voltage is applied between the burner plates m to reduce the gas on the surface of the burner plates m.
Perform ignition of the air mixture. Each of the above constituent members is fixed in position relative to each other on a movable base B provided with wheels.

Now, when you operate the switch on the control device C to start this heating system, the solenoid valve SV is opened and fuel gas is injected and supplied from the nozzle GN, and at the same time the blower F is started and air is supplied to the burner. Inside the main body, fuel gas and air are in a mixed state and flow in the direction of the burner plate m, passing through this and seeping out from the surface layer m1. On the other hand, a spark is generated between the spark electrode S to which a high voltage is applied and the burner plate m, and the air-gas mixture seeped into this area is ignited, and the flame quickly spreads to the surface of the burner plate m. It spreads throughout the entire body and combustion operation starts.

Here, in order to cause this surface combustion burner to perform efficient combustion, it is necessary to closely control the amount of gas supply and the amount of air supply. In other words, the ratio of the gas supply amount to the air supply amount (mixing ratio) is approximately equivalent to the stoichiometric ratio of a chemical reaction, and the flow rate of the gas-air mixture passing through the burner plate m is determined by the flame or leaving the surface of the burner plate m. It is set within the scope of not doing so.

As a result, stable combustion is maintained in the surface layer m1 of the burner plate m, resulting in a red-hot state, and radiant heat is radiated in an amount that depends on the temperature of the surface layer m1.

[Problems to be solved by the invention] In a surface combustion burner using a burner plate made of SUS matte,
The oxidative deterioration of the surface layer of the burner plate, which becomes red-hot, progresses significantly, and the SOS mat rapidly thins and collapses.
The lifespan of the burner plate is short; for example, the lifespan of the burner plate m of a conventional heater did not exceed 100 hours even during normal operation.

FIG. 4 shows the temperature distribution in the thickness direction of the burner plate m when the conventional surface combustion burner performs normal operation.

In Fig. 4, the temperature at the surface layer m1 of the burner plate m has reached 1200°C, which is 800°C as the normal temperature.
This is a harsh environment for SUS mats, which should adopt the following. On the other hand, since the SUS mat itself is a material with low thermal conductivity and is constantly cooled by the unburned gas-air mixture that passes through it, the temperature drops rapidly as it moves away from the surface layer m1. The temperature is below 800°C, which is a temperature that the SUS mat can withstand sufficiently.

Focusing on this point, the surface layer m1 of the burner plate m is replaced with a flame-resistant material, for example, a mat made of sintered A ho 3 fibers, that is, an SUS mat and a heat-resistant material mat are joined to form a two-layer structure. Attempts were made to use it as a burner plate.

However, since the sintering temperatures of SUS fibers and heat-resistant material fibers are considerably different, it is difficult to bond mats together by sintering. In addition, 2 parts using heat-resistant screws and nuts are also available.
Attempts have been made to connect the layers by screwing them together or sewing them together using heat-resistant wire, but the holes that pass through them and the heat-resistant material cause the uniformity of combustion to be lost on the combustion surface. Since the SUS mat deteriorated along the member, the desired effect of extending the life of the burner plate could not be obtained.

An object of the present invention is to provide a long-life surface combustion burner in which the bond between the SUS mat layer and the heat-resistant material layer is strong, and combustion uniformity on the combustion surface is ensured.

[Means for Solving the Problems] The surface combustion burner according to claim (1) of the present invention includes a first layer that is resistant to combustion and forms a gas combustion zone, and a gas supply to the first layer. A surface combustion burner having a second layer that supports the first layer, and a third layer that is sewn to the first layer and sintered to the second layer is arranged between the first layer and the second layer. be.

The surface combustion burner according to claim (2) of the present invention is provided by claim (1).
), in which a ceramic cloth is used as the first layer.

[Function] In the surface combustion burner according to claim (1) of the present invention, a premixed mixture of air and gas is supplied from the second layer side,
This mixture passes through the second layer, seeps into the first layer, and burns at the surface layer of the first layer, heating the surface layer to a red-hot state. Here, the first layer includes a flame-resistant material, such as a ceramic fiber mat, and the second layer includes:
SUS mats are generally used in consideration of strength and economy.

On the other hand, the first layer and the second layer are sewn together to the first layer,
It is firmly bonded to the second layer via a third layer that is sintered and bonded. That is, the third layer is made of a material that is easily sintered with the second layer, for example, the same material, and after the first layer and the third layer are sewn together, this is sintered and joined to the second layer, or the third layer is A second layer material is stacked on top of the layer and sintered to form a mat.

This eliminates the need for the second and third layers to be directly exposed to high temperatures due to gas combustion. Furthermore, since there are no holes or heat-resistant members penetrating the burner plate, the flow rate of the air-gas mixture on the combustion surface and the uniformity of the combustion state are maintained.

Here, the first layer is made of various heat-resistant materials, such as ceramic fiber mats, high melting point metal fiber mats,
Alternatively, woven cloth or terry cloth made of similar materials are used, but the materials for the first, second, and third layers must have the same porosity, or the porosity must be the same at each joint. It is desirable to prevent steps and sudden changes from occurring. The thread used for sewing is made of a flame-resistant material, such as Kanthal, a heat-resistant metal, or twisted thread or a single wire made of ceramic fiber, but it is preferable to use a thin thread from the viewpoint of uniform combustion.

In the surface combustion burner according to claim (2) of the present invention, the first layer is easier to handle than a ceramic fiber mat or the like,
Moreover, since the ceramic cloth is resistant to crushing or collapse due to stitching, the first layer and the third layer can be easily joined using, for example, an ordinary industrial sewing machine.

Examples of the invention] Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows the structure of the burner plate portion of a surface combustion burner according to an embodiment of the present invention, (a) is a front view of the burner plate M;
(b) is an enlarged cross-sectional view of a portion thereof as seen from the side. The surface combustion burner of this embodiment has a burner plate m having a single layer structure of SUS mat of the surface combustion burner of the conventional example, with AI203 cloth 1 as the first layer and SUS mat 2.3 as the second and third layers. The burner plate M has a three-layer structure.

In FIGS. 1(a) and (b), the first layer of Al2O3 cloth 1 is a nonwoven fabric made of Al2O3 long fibers with a diameter of 8 μm and has a thickness of 1 to 2 mm, and the second and third layers are SUS mats 2. .3 is made by forming long fibers of 5US316 with a diameter of 20 μm and a length of about 50 m111 into a mat shape and sintering them together, and the thicknesses are 4 mm and 0.5 mm, respectively. In addition, A I203 cloth 1 and SUS mat 2
．． The porosity of No. 3 is approximately equal to 90% or more.

This burner plate M is made by stacking Al2O3 cloth 1 with a thickness of 1 to 2 mm and SOS mat 3 with a thickness of 0.5 mm, and using a single wire of Kanthal, which is an alloy of iron, chromium, etc., and an industrial sewing machine. After sewing vertically and horizontally according to the base stitch pattern of approximately 10 mm square,
SUS mats 2 with a diameter of 2 mm are stacked on top of each other and sintered and bonded under pressure at a high temperature.

FIG. 2 shows the relationship between the gas mixture ratio of the gas-air mixture (the ratio between the actual air supply amount and the stoichiometric equivalent amount) in the surface combustion burner of this embodiment and the interface temperature of each layer of the burner plate M. It is a line diagram showing a relationship. Here, the flow rate of the mixture is 15 cm/
sec, methane CHa is selected as the gas fuel.

As shown in the diagram in Fig. 2, in the burner plate M in which the part where gas combustion progresses and becomes red hot is replaced with Al2O3 cloth, A I203 for various gas mixture ratios.
The interface between cloth and SUS mat 3 is 800℃ or less, SUS
The operation is maintained at 600°C or less at the interface of mat 2.3.

Therefore, the oxidation progress of SUS Mat 2.3 is slowed down, and the burner plate life, which was conventionally about 100 hours, reaches 5000 hours even under maximum load operation, and the lifespan of the burner plate reaches 5000 hours even under maximum load operation.
The flame splashing on the stitch pattern on the combustion surface during operation, which was observed in the burner plate with a two-layer structure made by sewing 3 cloth 1 and SUS mat 2, did not occur, and the uniformity of combustion was improved.

In this embodiment, the SUS mat and A+20s cloth were sewn together using Kanthal wire, but these materials can be selected and combined in various ways in consideration of heat resistance and economic efficiency. For example, applications such as replacing Al2O3 cloth with Tio2 cloth and replacing Kanthal wire with platinum wire are possible.

[Effects of the Invention] In the surface combustion burner of claim (1) of the present invention, since the burner plate surface layer, which is the gas combustion area, is composed of the first layer of a flame-resistant material, oxidative deterioration of the burner plate is prevented. Progress is slow. In addition, the first layer is connected to the second layer through the sewn third layer.
Since the layers are sintered and bonded, it is easy to manufacture and handle burner plates and surface combustion burners. Oxidative deterioration phenomenon is less likely to occur. Therefore, the life of the burner plate can be extended, the operating rate can be improved, and operating costs can be reduced, thereby increasing the practicality of the surface combustion burner.

Furthermore, since the first and third layers are joined by stitching, it is possible to freely select materials without considering matching such as sintering temperature difference or affinity between materials as in the case of sintering. .

In the surface combustion burner of claim (2) of the present invention, ceramic cloth is used, which is much easier to handle and cheaper than mats with a sintered structure, so the sewing work can be performed easily and with high efficiency. .

[Brief explanation of drawings]

FIG. 1 shows the structure of a surface combustion burner according to an embodiment of the present invention, in which (a) is a plan view and (b) is a partial sectional view. FIG. 2 is a diagram showing the relationship between the operating conditions of the surface combustion burner according to the embodiment of the present invention and the interfacial temperature of each layer of the burner plate. FIG. 3 is a schematic diagram showing the structure of a heating device for outdoor work, for explaining a conventional surface combustion burner. FIG. 4 is a diagram showing the temperature distribution in the cross section of the SUS mat of a conventional surface combustion burner. [Explanation of symbols of main parts] 1... Al2O3 cloth 2.3... SUS mat 4... Kanthal wire

Claims (2)

[Claims] (1) a first layer having combustion resistance and forming a gas combustion zone;
A surface combustion burner having a second layer that supplies gas to the first layer and supports the first layer, the second layer being sewn to the first layer and sintered to the second layer. A surface combustion burner characterized in that three layers are arranged between the first layer and the second layer. (2) The surface combustion burner according to claim 1, wherein a ceramic cloth is used as the first layer.