JPS5840087B2 - burner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a burner with a wide range of supply speeds of fuel and air mixtures or fuels that are sustainable in combustion.

Conventionally, it has been attempted to increase the temperature of the burner flame opening to increase the air-fuel mixture speed at blow-out, that is, the flame blow-out speed, in order to obtain a burner that can sustain combustion over a wide range of air-fuel mixture supply speeds.

For example, if a material with low thermal conductivity such as ceramic is used at the flame mouth to receive heat radiation from the flame, the temperature at the flame mouth increases due to the low thermal conductivity, and an increase in the flame blowout rate of the mixture is observed. It was done.

In general, there is a part of the flame called the flame base or flame stability region at the burner mouth or downstream of the flame holder (downstream of the air-fuel mixture or fuel flow). Heat is taken away by the holder and the temperature is lower than that of the flame further downstream, but if the temperature of the burner mouth or flame holder rises due to receiving heat from the flame, the temperature drop in that flame part will be less and the temperature will be lower. The flame extinguishment or surfacing of the air-fuel mixture or fuel increases the critical speed.

This invention further increases the temperature of the burner mouth and flame holder through an appropriate configuration to further increase the flame blowout speed of the supplied air-fuel mixture or fuel, thereby increasing the supply speed range of the air-fuel mixture or fuel that is sustainable for combustion. The invention is aimed at obtaining a wide burner, and the invention will be explained below with reference to embodiments shown in the drawings.

Figure 1a is a surface diagram and an end view of an embodiment of the present invention.
The figure is an enlarged sectional view of a part thereof.

In FIG. 1a, 1 is a mixture of fuel and air or fuel, which passes through a burner tube 2 and a flame 3 is formed downstream of the flame opening of the tube 2.

The flame opening of the burner tube 2 is made of metal with low thermal conductivity between the base and the end, as shown in Figure 1. Ceramic with low thermal conductivity is melted onto the end face of the base 4 of the burner tube 20 base to form a ceramic layer 5, and nickel with high thermal conductivity is melted thereon to form a nickel layer 6 at the end of the base. After forming the nickel layer 6, the nickel layer 6 is polished to give it luster, thereby improving the reflection of long wavelength light.

Furthermore, black chromium, which is a mixture of Cr2O3 and Cr, is plated on the nickel layer 6 to form a thin black chromium layer 7.

The reflectance of metals such as iron and aluminum conventionally used for the burner mouth or flame holder is shown in Figure 3, which shows the relationship between the wavelength λ of the emitted wave from the flame, the reflectance ρ, and the absorption rate α. , as shown by the curve Fep Al, was large overall except for short wavelength regions, and almost all radiation waves from the flame were reflected except for some short wavelength regions.
As in the above embodiment, the metal base 4 of the burner tube 20 base
In the case where a shiny nickel layer 6 forming an end portion is bonded to a ceramic layer 5, and a thin black chromium layer 7 containing a transition metal is bonded on top of the shiny nickel layer 6, radiation waves from the flame can be absorbed as shown in the curved line. The area that absorbs a lot can be expanded in the long wavelength area 1, and the area that reflects a lot can be narrowed accordingly.

The characteristic of this embodiment is as shown in the curve in Fig. 3 because
In the short range of the radiation waves received from the flame, the radiation waves are converted into conductive heat by the black chrome layer 7, which passes through the nickel layer 6 and is absorbed and stored in the ceramic layer 5, while this heat is transferred to the black chrome layer 7. The flame is radiated from the surface of the black chrome layer 70, but since the temperature of the flame is higher than the temperature of the surface of the black chrome layer 70, the energy received from the flame increases as a whole and heat is stored, and the radiated wave becomes thin black at the longer wavelength. While the heat transmitted through the chromium layer 7 is reflected on the surface of the nickel layer 60, the heat accumulated in the ceramic layer 5 is conducted through the black chromium layer 7, but the radiation rate from the surface of the layer 70 (as shown in Figure 3) This is because, since the absorption rate (equal to the absorption coefficient α) is small, the radiation is hardly radiated, and the above-mentioned absorption and reflection of the radiated waves occur at the same time between the short and long wavelength regions.

The wavelength distribution of the emitted waves from the flame 3 shown in Figure 1a is:
Regarding the premixed flame of propane gas (the non-luminous flame when fuel and air are mixed in advance and supplied to the burner and burned),
It looks like curve a in Figure 4.

In FIG. 4, the horizontal axis shows the wavelength λ and the vertical axis shows the radiation rate εm.

In the embodiment described above, such radiation waves from the flame 3 are accumulated as heat in the ceramic layer 5 through the black chromium layer 7 and the nickel layer 6 according to the characteristics shown in the curve of FIG. Raise its temperature.

While the heat stored in the ceramic layer 5 is prevented from escaping to the upstream side of the base 4 of the burner tube 20 due to the heat insulating effect of the ceramic, there is almost no radiation loss escaping from the black chrome layer 7 downstream of the base 4. ,.

This is because the block chrome is black, and the monochromatic radiation E5° of a black body is shown with respect to the wavelength λ, as shown by the curve cp d corresponding to the black body temperature of 6000 and 800' in Figure 5. is mostly in the infrared region, and its radiation loss E is the value obtained by multiplying the curve in Figure 3 by the value in the vertical axis direction of the curve cs d in Figure 5, that is, EE = (1 - ρ) Eb2
This is because heat loss is small at wavelengths greater than 6μ, and is almost non-existent at wavelengths greater than 10μ.

The reason why the nickel layer 6 is made glossy is to more effectively prevent radiation loss from the nickel layer 6.

Therefore, the layers 5, 6, which are provided at the tip of the burner tube 2,
Although the portion 7 receives radiant heat from the flame, the heat loss is small, so the temperature rises a lot and the flame blowout limit speed of the air-fuel mixture or fuel increases.

When the flame on the shattered burner repeats the cycle of ignition and extinguishing, there is little heat loss, so there is little drop in burner temperature when extinguishing, and the flame stability when re-igniting is good.

In this embodiment, the ceramic layer 5 is formed by thermal spraying on the upper end of the base 4 of the burner tube 2, so there is no need to use a device or adhesive to fix the ceramic layer 5 to the upper end of the base 4. , and the nickel layer 6 is replaced by the ceramic layer 5.
(The reason why it is formed by thermal spraying is that not only does it not require the use of fixing devices or adhesives, but it also improves the conduction of heat received from the flame.

In this embodiment, a shiny nickel layer 6 is bonded to the base 4 of the burner tube 2 via a ceramic layer 5, and a black chrome layer 7 containing a transition metal is bonded on top of the nickel layer 6. Instead of layer 7 an oxide of a transition metal, for example M o O.

MnO, NiO, N1O-CuO-Cu20p2
2 3 Sulfides, carbides such as Z n Cz T t C-H
f C or a layer of boride ZrB2 s LaB6, a layer of stainless steel in place of the nickel layer 60, and a metal with low thermal conductivity such as stainless steel in place of the ceramic layer 5 or ceramic layer 5 and nickel layer 6. A similar effect was obtained using a layer of

Therefore, if stainless steel is used for the base 4 of the burner tube 20, the ceramic layer 5 may be omitted.

In this case, the nickel layer 6 may be replaced with a stainless steel layer and integrated with the base 4 made of stainless steel.

However, since ceramic has a lower thermal conductivity than stainless steel, using the ceramic layer 5 increases the flame extinguishing speed of the air-fuel mixture. It would be possible to use a relatively weak metal for the base 4 of the burner tube 20.

However, zinc is particularly sensitive to heat, so if you use zinc,
(The ceramic layer 5 is bonded to the burner tube 20 base 4 using a ceramic adhesive without thermal spraying.

On the other hand, stainless steel contains a lot of Cr, but by oxidizing or sulfurizing the Cr in this stainless steel, Cr
oxide film or sulfide film can be deposited.

A burner nozzle with this oxide or sulfide precipitated on its surface has characteristics similar to those shown by the curved line in FIG.

To deposit this oxide film, a molten salt solution of sodium dichromate is used and its oxidation reaction is utilized.

Further, in order to deposit a sulfide film, it is immersed in a mixed aqueous solution of caustic soda and an inorganic salt containing sulfur.

FIG. 2a is a sectional view and an end view of another embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the main part thereof.

In this embodiment, the present invention is applied to a burner that performs spray combustion, and as shown in FIG. 2a, fuel sprayed from a nozzle 8 forms a flame 10 on a flame holder 9 and burns stably. There is.

The frame holder 9 is similar to the embodiment shown in FIGS. 1a and 1b, and has a low thermal conductivity between the metal base and the end. As shown, on a stainless steel substrate 11 with a smooth surface and low thermal conductivity that forms the base of the base, the ends of the base are sequentially formed using the same method as in the case of Figure 1. A nickel layer 12 having high conductivity and a black chromium layer 13 containing a transition metal are bonded together i-Q, and a large number of primary air intake holes 14 are provided through them.

The matters described for the embodiment shown in FIG. 1 axb also hold true for this embodiment.

As described above, the burner according to the present invention has an appropriate configuration, which increases the temperature of the burner mouth part and flame holder compared to the conventional one, and further improves the speed of blowing out the fuel and air mixture or the fuel flame. This has the effect of widening the supply speed range of fuel mixture or fuel that can increase combustion efficiency.

[Brief explanation of the drawing]

1A and 1B are a side view 1, an end view, and an enlarged sectional view of the main parts of one embodiment of the present invention, and FIGS. 2A and 2B are a sectional view, an end view, and an enlarged sectional view of the main parts of another embodiment of the present invention. Figure 3 is a characteristic diagram showing the reflectance and absorption rate for the wavelength of emitted waves from the flames of burner nozzles made of different materials. FIG. 5 is a characteristic diagram showing the relationship between the radiation power and the wavelength of the radiation wave. FIG. 5 is a characteristic diagram showing the relationship between the monochromatic radiation power of a black body and the wavelength. 2... Burner tube whose tip forms a flame port, 5... Ceramic layer, 6, 12... Shiny metal layer such as nickel or stainless steel, 7, 13... Black containing transition metal Chrome layer, 9...°Frame holder, 11...
Stainless steel board of frame holder 9.

Claims (1)

[Claims] 1. A burner mouth part or a base body made of metal of a flame holder and having a low thermal conductivity between the base part and the end part,
The base of the burner nozzle or flame holder is characterized in that a layer of black chromium residue containing a transition metal, or a layer of transition metal oxide, sulfide carbide, or boride is formed on the end face of the base. 2. A burner according to claim 1, wherein the base and end portions are made of a metal with high thermal conductivity and are bonded together via a ceramic layer. 3. The burner according to claim 2, wherein the ceramic layer bonded between the base and end of the base of the burner flame port or the flame holder is formed by thermal spraying ceramic onto the base. 4. The burner according to claim 2, wherein the metal layer at the burner mouth portion or the end portion bonded to the ceramic layer of the base of the frame holder is formed by thermally spraying metal onto the ceramic layer. 5 The base of the burner mouth part or frame holder is made of a metal with high thermal conductivity at its base and end. 4 Both are bonded together via a metal layer with low thermal conductivity such as stainless steel. A burner according to claim 1. 6. A patent in which the base of the burner mouth or flame holder is made of a metal with low thermal conductivity such as stainless steel, and a metal layer with high thermal conductivity such as nickel is bonded to the V. A burner according to claim 1. 7 The base of the burner mouth or flame holder is made of a metal with high thermal conductivity at its base, a metal with low thermal conductivity such as stainless steel at the end, and the two are glued together. A burner according to claim 1. 8. The burner according to claim 1, wherein the burner mouth part or the base body of the flame holder is integrally formed at its base and end with a metal having low thermal conductivity such as stainless steel. 9 A film of chromium oxide or sulfide contained in stainless steel is deposited on the end face of the stainless steel forming the burner flame opening or the end of the frame holder base,
9. The burner according to claim 7 or 8, wherein a layer of chromium oxide or sulfide is formed.