TW201321102A - Combustion device and runner cleaning method of melting metal container - Google Patents

Abstract

The objective is to enable a combustion device to effectively melt down and delete scull attached upon the runner of a melting metal container in a short time to properly clean the runner of the melting metal container. The objective is resolved by using a combustion device disposed upon a central portion of a front end of combustion burner 10 with plural nozzles 13a for combustion to be used for inner flame having supporting gas discharging nozzles 11a capable of discharging supporting gas in a high speed and fuel gas discharging nozzles 12a for discharging fuel gas, and disposed upon an outer circumference of the nozzles for combustion to be used for inner flame with plural nozzles 13b for combustion to be used for outer flame having supporting gas discharging nozzles 11b capable of discharging supporting gas in a high speed and fuel gas discharging nozzles 12b for discharging fuel gas.

Description

Burning device and sprue cleaning method for molten metal container

The present invention relates to a combustion apparatus for melting a metal block attached to a runner of a molten metal container such as a tundish, and a metal block which is melted by the combustion apparatus to remove a sprue attached to the molten metal container, A sprue cleaning method for a molten metal container that prevents a sprue of a molten metal container from being clogged. In particular, it is characterized in that the metal block which is adhered to the runner of the molten metal container can be efficiently melted in a short time, and the runner of the molten metal container can be appropriately washed.

Conventionally, in a molten metal container such as a funnel, as shown in Patent Document 1, the molten metal is solidified by suction of heat energy through a refractory material or the like of the runner portion of the molten metal, and a metal block is attached to the runner. There is a problem that the sprue is blocked. Further, as shown in Patent Document 2, in the other form of the runner, there is a gate (the upper nozzle of the funnel), and the gate has the same problem.

Therefore, conventionally, metal blocks which are attached to the runner of the molten metal container have been continuously removed to prevent the runner from being clogged in the molten metal container.

Moreover, when the metal block attached to the runner is removed in this manner, it is conventionally heated and melted by using a burner of a burner to remove the metal block attached to the runner, but there is a desire to heat and melt to remove the adhesion. The metal block of the road requires a lot of time.

In addition, in order to rapidly heat and melt to remove the metal attached to the runner The block also uses an oxygen jet lance to blow oxygen from the opposite side of the burner.

However, when the oxygen jet lance is used to blow oxygen, the operator sets the oxygen jet lance to an appropriate position for oxygen injection, so that the operation is complicated and the metal block is heated and melted. It produces smoke and the like, and it has a bad influence on the operator.

Further, as shown in Patent Document 2, in the past, an invention has been proposed in which a seal cover is provided on the outlet side of a gate as a funnel of a sprue, and a plasma torch is passed through the inside of the envelope. The metal block attached to the runner is sprayed with a plasma jet using a non-oxidizing gas, a reducing gas, or a mixed gas as a raw material gas to wash the runner.

However, when the envelope is provided on the outlet side of the gate as the funnel of the runner, and the raw material gas as described above is used as the plasma jet to be blown from the plasma torch, the operation is complicated and costly, and there is no possibility. The problem of metal blocks attached to the runner is quickly removed.

[Previous Technical Literature] (Patent Literature)

Patent Document 1: Japanese Laid-Open Patent Publication No. Hei 9-220647

Patent Document 2: Japanese Laid-Open Patent Publication No. 11-138240

The present invention solves the above-mentioned problems in the case of melting a metal block attached to a runner of a molten metal container such as a funnel.

That is, the subject of the present invention is to efficiently melt a metal attached to a sprue of a molten metal container in a short time when the metal block attached to the runner of the molten metal container is removed by melting by a burning device. Block, and properly clean the runner of the molten metal container.

In the combustion apparatus of the present invention, in order to solve the above problems, a combustion nozzle for the inner flame is provided at the center of the burner front end, and the outer flame is provided on the outer peripheral side of the combustion nozzle for the inner flame. The nozzle is used, and the inner flame and the outer flame can be independent and controlled.

Further, in such a combustion apparatus, a plurality of combustion nozzles for the internal flame having the combustion-supporting gas delivery nozzle for delivering the combustion-supporting gas and the fuel gas delivery nozzle for discharging the fuel gas can be provided at the center of the burner front end. Further, a plurality of combustion nozzles for the outer flame having the combustion-supporting gas delivery nozzle for supplying the combustion-supporting gas and the fuel gas delivery nozzle for discharging the fuel gas can be provided on the outer peripheral side of the combustion nozzle for the inner flame.

Here, in the combustion apparatus, oxygen, air, or the like can be used as the combustion-supporting gas. However, in order to improve the combustibility of the fuel gas, it is preferred to use oxygen gas for the combustion-supporting gas.

Further, in the combustion apparatus, when the combustion-supporting gas is sent from the respective combustion-supporting gas delivery nozzles, the metal block adhering to the runner of the molten metal container is efficiently melted in a short time and blown forward. Preferably, the combustion-supporting gas is sent from the respective combustion-supporting gas delivery nozzles at a high speed. On the other hand, when the speed at which the combustion-supporting gas is sent is too fast, the flame rises and stable combustion cannot be performed. After that. Therefore, compare Preferably, the delivery rate of the combustion-supporting gas sent from the respective combustion-supporting gas delivery nozzles is set to be in the range of 450 to 500 m/s.

In addition, as described above, in order to stably burn the fuel gas even when the combustion-supporting gas is sent from the combustion-supporting gas delivery nozzle at a high speed, it is preferable to provide a concave portion for combustion at the tip end portion of each of the above-described combustion nozzles.

Further, as described above, a plurality of combustion nozzles for the inner flame and the outer flame are provided at the front end of the burner, and the combustion-supporting gas for the combustion nozzles for the inner flame and the outer flame is sent out to the nozzle and the fuel gas. When the nozzles are supplied and the combustion-supporting gas and the fuel gas are appropriately supplied, the combustion-supporting gas supply pipe for supplying the combustion-supporting gas to the combustion-supporting gas for the combustion of the internal flame can be used for the internal flame. The fuel gas supply nozzle of the combustion nozzle, the fuel gas supply pipe for supplying the fuel gas, the combustion gas supply nozzle for the combustion gas for the external flame, and the combustion gas supply pipe for the external flame for supplying the combustion-supporting gas, and the external flame The fuel gas supply nozzle of the combustion nozzle for supplying the external gas fuel gas supply pipe for supplying the fuel gas has a multi-tube structure.

Further, in the combustion apparatus, in order to make it possible to perform appropriate combustion in the adjacent combustion nozzles, and to complement each other, the inner diameter of the above-mentioned combustion-supporting gas delivery nozzle is set to D, and When the interval between the combustion-supporting gas delivery nozzles of the adjacent combustion nozzles is P, it is preferable to set the condition to satisfy 3≦P/D≦5.

Further, the combustion apparatus of the present invention is used as a sprue washing apparatus for a molten metal container. Generally, the cross section of the runner of the molten metal container is a circle having a diameter of 50 mm or more and 400 mm or less, or a circle The same area of the face.

Further, in the sprue cleaning method of the molten metal container of the present invention, the above-described burning device is used to melt and remove the metal block attached to the runner of the molten metal container.

Here, when the metal block attached to the runner of the molten metal container is melted and removed by the above-described combustion apparatus, it is preferable to melt the metal block attached to the runner of the molten metal container at the beginning of the process. The combustion of the combustion nozzle for the inner flame is stronger than the combustion of the combustion nozzle for the outer flame. In addition, in the initial stage of melting the metal block attached to the runner of the molten metal container, only the combustion nozzle for the inner flame described above may be burned, and only the combustion nozzle for the outer flame may be used thereafter. Burning.

In the combustion apparatus of the present invention, the combustion nozzle for the inner flame is provided at the center of the burner front end, and the combustion nozzle for the outer flame is provided on the outer peripheral side of the combustion nozzle for the inner flame, and is independent. Since the inner flame and the outer flame are controlled, when the runner of the molten metal container is washed by using the burning device, the inner flame can be used in the initial stage of melting the metal block attached to the runner of the molten metal container. The combustion of the combustion nozzle is stronger than the combustion of the combustion nozzle for the outer flame. Further, in the initial stage of melting the metal block of the runner attached to the molten metal container, only the combustion nozzle for the inner flame described above can be burned, and only the combustion nozzle for the outer flame can be burned thereafter. .

Further, in the combustion apparatus of the present invention, a plurality of combustion nozzles for the inner flame provided at the front end of the burner, and a plurality of burners provided on the outer peripheral side thereof In the combustion nozzle for the outer flame, when the combustion-supporting gas is sent from the combustion-supporting gas delivery nozzle to burn the fuel gas, the combustion-supporting gas can be sent from the combustion-supporting gas delivery nozzle at a high speed to strongly burn the fuel gas. Further, when the combustion-supporting gas is sent out from the combustion-supporting gas delivery nozzle at a high speed in this manner, even if the flame of a part of the combustion nozzle becomes unstable, it can be supplemented by the combustion of the adjacent combustion nozzle. Each combustion nozzle performs stable combustion without causing a flame to fly.

Further, when the metal block attached to the runner of the molten metal container is melted and removed by using the combustion apparatus of the present invention, a plurality of combustion nozzles for the inner flame provided at the front end of the burner, and a plurality of outer flames are used. In the combustion nozzle, the combustion gas can be sent from the combustion-supporting gas delivery nozzle at a high speed to burn the fuel gas. Even if the conventional oxygen jet spray gun is not used, it can be used for a plurality of internal flames provided at the front end of the burner. The combustion nozzle and the combustion nozzles for the plurality of outer flames are used to rapidly melt the metal block adhering to the runner of the molten metal container, and can be efficiently and quickly removed and adhered to the molten metal container in a short time. The metal block of the runner is able to properly clean the runner of the molten metal container.

Hereinafter, a combustion apparatus according to the present embodiment and a sprue cleaning method for melting and removing a molten metal container attached to a metal block of a molten metal container using the combustion apparatus will be specifically described based on the drawings. In addition, the burner apparatus of the present invention and the method of cleaning the runner of the molten metal container are not limited to the embodiments described below, and may be appropriately modified without departing from the scope of the invention.

As shown in FIG. 1 to FIG. 3, in the combustion apparatus of the present embodiment, a plurality of combustion-supporting gases composed of oxygen or air at a high speed of sound velocity or higher are provided in a central portion of the front end of the burner 10. The combustion-supporting gas delivery nozzle 11a of the Laval nozzle (La Laura nozzle) and the combustion nozzle 13a for the internal flame of the fuel gas delivery nozzle 12a that sends out the fuel gas, and the combustion nozzle 13a for the internal flame The outer peripheral side is provided with a plurality of combustion-supporting gas delivery nozzles 11b that use a Laval nozzle that can deliver a combustion-supporting gas composed of oxygen or air at a high speed equal to or higher than a sound velocity, and an outer flame of the fuel gas delivery nozzle 12b that sends the fuel gas. The combustion nozzle 13b is used, and the combustion portion 13b for the outer flame is provided with a cooling portion 14 for cooling the burner 10.

Here, as shown in Fig. 2, in each of the combustion nozzles 13a and 13b for the inner and outer flames, the combustion recesses 15a and 15b are provided at the front end of each of the combustion nozzles 15a and 15b. The combustion-supporting gas is sent out from the above-described combustion-supporting gas delivery nozzles 11a and 11b by the recesses 15a and 15b, and the fuel gas is sent out from the fuel gas delivery nozzles 12a and 12b, and the fuel gas is supplied to the combustion recesses 15a and 15b. The combustion-supporting gas contacts and burns.

In addition, when the combustion-supporting gas is supplied to each of the combustion-supporting gas delivery nozzles 11a and 11b of the combustion nozzles 13a and 13b for the inner and outer flames, and the fuel gas is supplied to the fuel gas delivery nozzles 12a and 12b. In the present embodiment, as shown in Fig. 3, the combustion-supporting gas supply pipe 16a for the inner flame that supplies the combustion-supporting gas to the combustion-supporting gas supply nozzle 11a of the combustion nozzle 13a for the inner flame is used for the inner flame. The fuel gas delivery nozzle 12a of the combustion nozzle 13a supplies the fuel gas for the internal flame fuel gas The supply pipe 17a, the combustion-supporting gas supply nozzle 16b for supplying the combustion-supporting gas, and the fuel gas delivery nozzle 12b for the external flame combustion nozzle 13b are supplied to the combustion-flammable gas delivery nozzle 11b for the external flame. The outer gas fuel gas supply pipe 17b for fuel gas is arranged in a concentric manner so as to have a multi-tube structure, and is connected to a burner in which the combustion nozzles 13a, 13b for the inner flame and the outer flame are provided as described above. 10 nozzle portion 10a at the front end.

In the combustion apparatus of the present embodiment, the control device 20 controls the combustion nozzles 13a for supplying the internal flame and the combustion for the outer flame from the combustion-supporting gas supply device 21. Each of the combustion-supporting gas of the nozzles 13b sends out the amount of the combustion-supporting gas of the nozzles 11a and 11b, and controls the supply of the combustion gas nozzles 13a for the internal flames and the combustion nozzles 13b for the external flames from the fuel gas supply device 22. The amount of combustion gas that the fuel gas sends out of the nozzles 12a, 12b.

Further, as shown in Fig. 5, in the molten metal container 30 such as a funnel, the metal block 33 adhering to the portion of the refractory 31 through which the molten metal passes is provided, and the combustion of this embodiment is used. When the apparatus is being melted, the front end of the burner 10 is attached to the portion of the runner 32, and the combustion recess 15a of each of the combustion nozzles 13a and 13b for the inner flame and the outer flame is attached. 15b, the combustion-supporting gas is sent from the combustion-supporting gas delivery nozzles 11a and 11b, and the fuel gas is sent out from the fuel gas delivery nozzles 12a and 12b, and the fuel gas is used for each of the combustion nozzles 13a for the inner flame and the outer flame. 13b burns and melts the metal block 33 attached to the portion of the runner 32.

Here, as described above, the combustion concave portions 15a and 15b of the combustion nozzles 13a and 13b for the inner and outer flames are respectively supplied with the combustion-supporting gas from the combustion-supporting gas supply nozzles 11a and 11b, and the fuel is supplied. When the gas is sent from the fuel gas delivery nozzles 12a and 12b, the combustion-supporting gas and the fuel gas are mixed and mixed in each of the combustion concave portions 15a and 15b, and a stable flame can be obtained in each of the combustion nozzles 13a and 13b. It also prevents the flame from generating a backfire inside the burner 10.

Here, when the combustion-supporting gas is supplied from the combustion-promoting gas delivery nozzles 11a and 11b provided in the respective combustion nozzles 13a and 13b for the inner and outer flames at a high speed equal to or higher than the speed of sound, the inner flame is used. The high-speed flame of each of the combustion nozzles 13a, 13b for the outer flame causes the metal block 33 adhering to the runner 32 to be rapidly melted, and the metal block attached to the portion of the runner 32 is rapidly melted. 33.

In addition, as described above, when the combustion-supporting gas is sent out from the combustion-supporting gas delivery nozzles 11a and 11b at a high speed equal to or higher than the sound velocity, the above-described combustion recesses for the respective combustion nozzles 13a and 13b for the inner flame and the outer flame are used. In the case of 15a and 15b, the flame is stabilized by the flame, and the combustion of the adjacent combustion nozzles 13a and 13b does not cause the flame to fly and disappear, and stable combustion can be performed in each of the combustion nozzles 13a and 13b. .

Here, when the delivery speed of the combustion-supporting gas sent from the respective combustion-supporting gas delivery nozzles 11a and 11b described above is slow, the molten metal block 33 cannot be pushed forward as described above and appropriately blown. On the other hand, when the delivery speed is too fast, the flames of the respective combustion nozzles 13a, 13b rise to make the combustion unstable, and the combustion efficiency is lowered, and the noise is accelerated. The rate is reduced and becomes larger. Therefore, it is preferable that the delivery rate of the combustion-supporting gas sent from each of the combustion-supporting gas delivery nozzles 11a and 11b is set to be in the range of 450 to 500 m/s.

In addition, in each of the combustion nozzles 13a and 13b for the inner flame and the outer flame, the adjacent combustion nozzles 13a, 13b, 13a, and 13b are appropriately combusted with each other, and the combustion of each other can be complemented. As shown in Fig. 1, it is preferable that the inner diameter of the combustion-supporting gas supply nozzles 11a and 11b is D, and the combustion nozzle 13a for the inner flame and the combustion nozzle 13b for the outer flame are preferably phased. When the interval between the combustion-supporting gas delivery nozzles 11a, 11b, 11a, and 11b of the adjacent combustion nozzles 13a, 13b, 13a, and 13b is P, the condition of 3≦P/D≦5 is satisfied.

Further, as described above, when the fuel gas is used to burn the fuel gas in the combustion nozzles 13a and 13b for the inner flame and the outer flame, and the metal block 33 adhering to the runner 32 is melted, the initial stage is In the stage, the amount of the combustion-supporting gas sent from the combustion-supporting gas for the internal flame to the nozzle 11a and the fuel gas sent from the fuel for the internal flame to the fuel gas sent from the nozzle 12a are controlled by the control device 20 described above. The amount is larger than the amount of the combustion-supporting gas sent from the combustion-supporting gas supply nozzle 11b for the outer flame and the amount of the fuel gas sent from the fuel gas delivery nozzle 12b for the outer flame, as shown in Fig. 6, It is preferable that the combustion of the inner flame combustion nozzle 13a is stronger than the combustion of the outer flame combustion nozzle 13b.

As a result, even if the opening of the runner 32 becomes small due to the metal block 33 attached to the runner 32, the metal block 33 of the center portion of the runner 32 is burned by the flame of the combustion nozzle 13a for the inner flame. Still being melted quickly, The opening is gradually enlarged by passing through the runner to appropriately melt the metal block 33 attached to the runner 32, and to prevent flame backlash. In addition, since the surrounding air is prevented from being caught by the outer flame of the combustion nozzle 13b for the outer flame described above, it is possible to reduce the speed attenuation of the inner flame and the temperature drop.

Further, in order to melt the metal block 33 at the center portion of the runner 32 in this manner, the through hole of the runner 32 to which the metal block 33 is attached is enlarged to a certain extent, and the combustion is performed from the outer flame. The amount of the combustion-supporting gas sent from the gas delivery nozzle 11b and the amount of the fuel gas sent from the fuel gas delivery nozzle 12b for the outer flame are increased, and the combustion of the combustion nozzle 13b for the outer flame is enhanced to be melted. A metal block 33 attached to the peripheral portion of the runner 32.

Furthermore, in the above-described embodiment, the combustion of the combustion nozzle 13a for the inner flame is further reduced by the combustion of the combustion nozzle 13b for the outer flame at the initial stage of melting the metal block 33 attached to the runner 32. Although it is strong, the combustion of the combustion nozzle 13b for the outer flame is stronger than the combustion of the combustion nozzle 13a for the inner flame at the later stage of melting the metal block 33 attached to the runner 32.

Further, in the initial stage of melting the metal block 33 attached to the runner 32, only the combustion nozzle 13a for the inner flame is burned, and the through hole of the runner 32 to which the metal block 33 is attached is changed. When it is large to some extent, only the combustion nozzle 13b for the outer flame is burned.

As described above, in the present invention, the combustion of the combustion nozzle 13a for the inner flame and the combustion of the combustion nozzle 13b for the outer flame are independently controlled, and the opening of the runner 32 is adhered. When the metal block 33 is made smaller, the inner flame of the combustion nozzle 13a for internal flame is burned by the outer flame. The outer flame of the nozzle 13b is also strong, so that the metal block 33 at the center portion of the runner 32 is melted, and the fuel is concentrated in order to gradually increase the opening of the through runner 32, and the opening is passed through the runner 32. When the temperature is increased to a certain extent, the combustion of the combustion nozzle 13b for the outer flame is stronger than the combustion of the combustion nozzle 13a for the inner flame, and the fuel is concentrated in order to enlarge the opening through the runner 32. Therefore, the fuel can be used efficiently, and the runner 32 can be washed in a shorter time than in the past.

10‧‧‧ burner

10a‧‧‧Nozzle Department

11a‧‧‧Combustible gas delivery nozzle

11b‧‧‧Combustible gas delivery nozzle

12a‧‧‧fuel gas delivery nozzle

12b‧‧‧fuel gas delivery nozzle

13a‧‧‧Combustion nozzle

13b‧‧‧Combustion nozzle

14‧‧‧Department of Cooling

15a‧‧‧Concave recess for combustion

15b‧‧‧burning recess

16a‧‧‧Inflammable gas supply pipe for internal flame

16b‧‧‧Combustion gas supply pipe for outer flame

17a‧‧‧Inner flame fuel gas supply pipe

17b‧‧‧External flame fuel gas supply pipe

20‧‧‧Control device

21‧‧‧Combustible gas supply device

22‧‧‧fuel gas supply device

30‧‧‧Metal metal containers

31‧‧‧ Refractory

32‧‧‧Runner

33‧‧‧metal block

D‧‧‧Inside diameter of the combustion-supporting gas delivery nozzle

P‧‧‧Interval between adjacent combustion-supporting gas delivery nozzles

Fig. 1 is a schematic front view showing a front end side of a burner in a combustion apparatus according to an embodiment of the present invention.

Fig. 2 is a cross-sectional explanatory view showing a combustion nozzle provided at the tip end of the burner in the combustion apparatus of the above embodiment.

In the combustion apparatus of the above-described embodiment, the combustion-supporting gas is supplied to the combustion gas supply nozzle of the combustion nozzle for the inner flame provided at the tip end of the burner, and the combustion-supporting gas for the combustion nozzle for the fuel and the outer flame. A schematic cross-sectional explanatory view of a structure in which a nozzle and a combustion nozzle are respectively supplied with a combustion-supporting gas and a fuel gas.

In the combustion apparatus of the above-described embodiment, the control device controls the amount of the combustion-supporting gas and the fuel gas supplied to the combustion nozzle for the internal flame, and controls the combustion for the external flame. A block diagram of the composition of the combustion-supporting gas and fuel gas of the nozzle.

Fig. 5 is a schematic cross-sectional explanatory view showing a state in which a metal block attached to a runner of a molten metal container is melted by using the combustion apparatus of the above embodiment.

Fig. 6 is a view showing the initial stage of melting a nozzle attached to a molten metal container by using the combustion apparatus of the above-described embodiment, and burning the combustion nozzle for the inner flame is stronger than the combustion of the combustion nozzle for the outer flame. A schematic illustration of the status.

10‧‧‧ burner

11a, 11b‧‧‧Combustible gas delivery nozzle

12a, 12b‧‧‧fuel gas delivery nozzle

13a, 13b‧‧‧ burner nozzle

16a‧‧‧Inflammable gas supply pipe for internal flame

16b‧‧‧Combustion gas supply pipe for outer flame

17a‧‧‧Inner flame fuel gas supply pipe

17b‧‧‧External flame fuel gas supply pipe

D‧‧‧Inside diameter of the combustion-supporting gas delivery nozzle

P‧‧‧Interval between adjacent combustion-supporting gas delivery nozzles

Claims (8)

A combustion apparatus is provided with a combustion nozzle for an internal flame at a center portion of a burner front end, and a combustion nozzle for an outer flame is provided on an outer peripheral side of the combustion nozzle for the inner flame, and the inner flame and the outer flame can be provided. Independent and controlled. The combustion apparatus according to claim 1, wherein a plurality of combustion-supporting gas delivery nozzles for supplying a combustion-supporting gas and an internal flame of a fuel gas delivery nozzle for delivering the fuel gas are provided at a central portion of the burner front end. In the combustion nozzle, a plurality of combustion nozzles for the outer flame having the combustion-supporting gas delivery nozzle for sending the combustion-supporting gas and the fuel gas delivery nozzle for discharging the fuel gas are provided on the outer peripheral side of the combustion nozzle for the inner flame. The combustion apparatus according to claim 2, wherein a combustion concave portion is provided at a front end portion of each of the combustion nozzles, and the combustion-supporting gas delivery nozzle and the fuel gas are supplied to the combustion concave portion. nozzle. The combustion apparatus according to the second aspect or the third aspect of the invention, wherein the combustion-supporting gas supply pipe for supplying the combustion-supporting gas to the combustion-supporting gas delivery nozzle of the combustion nozzle for the inner flame is In the fuel gas supply nozzle of the combustion nozzle for the internal flame, the fuel gas supply pipe for supplying the fuel gas, and the combustion gas supply nozzle of the combustion nozzle for the external flame, the external combustion gas supply pipe for supplying the combustion-supporting gas The fuel gas supply pipe for the external flame that supplies the fuel gas to the fuel gas delivery nozzle of the combustion nozzle for the external flame is configured as a multiple pipe structure. The combustion apparatus according to claim 2, wherein the delivery rate of the combustion-supporting gas sent from the combustion-supporting gas delivery nozzle is in the range of 450 to 500 m/s. The combustion apparatus according to claim 2, wherein the inner diameter of the combustion-supporting gas delivery nozzle is set to D, and the combustion-supporting gas of the adjacent combustion nozzle is sent out between the nozzles. When the interval is set to P, the condition of 3≦P/D≦5 is satisfied. A method for cleaning a sprue of a molten metal container by using the burning device according to the first or second aspect of the patent application, in the initial stage of melting a metal block attached to a sprue of a molten metal container, to cause the aforementioned inner flame The combustion nozzle used for combustion is more intense than the combustion nozzle for the outer flame. The method of cleaning a sprue of a molten metal container according to the seventh aspect of the invention, wherein, in the initial stage of melting the metal block attached to the runner of the molten metal container, only the combustion nozzle for the inner flame is used. It burns, and only the combustion of the combustion nozzle for the outer flame is performed thereafter.