JP2017020758A - Burner for heating inside of container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent back fire.SOLUTION: A burner 20 for heating the inside of a container is connected with a gas supply device 22, and mounted on a mouth of a container 24. The burner 20 for heating the inside of the container includes a gas passing section 30, a gas injecting section 32, a metal knit 34 kept into contact with a surface of the gas injection section 32, and a connecting section 36. The gas supplied from the gas supply device 22 passes through the gas passing section 30. The gas injecting section 32 is connected to the gas passing section 30 and is hollow. The connecting section 36 is connected with the container 24 so that the gas injecting section 32 and the metal knit 34 are opposed to an inner face of the container 24. The gas injecting section 32 has a plurality of gas injection holes 50. The plurality of gas injection holes 50 are covered by the metal knit 34. The metal knit 34 is spot welded to the gas injecting section 32 at a joining portion of the gas passing section 30 and the gas injecting section 32.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an in-container heating burner.

  Patent document 1 discloses a molten metal holding furnace. This molten metal holding furnace is composed of three chambers including a hot water receiving chamber having a hot water inlet, a molten metal heating chamber, and a hot water outlet chamber. The molten metal holding furnace includes a molten metal communicating portion at the bottom of each chamber between the hot water receiving chamber and the molten metal heating chamber and between the molten metal heating chamber and the molten metal heating chamber. A surface combustion heating device is provided on the lower surface of the upper lid of the molten metal heating chamber. An exhaust cylinder with an open / close damper that communicates with the upper heating space of the molten metal heating chamber is provided.

  A surface combustion burner is provided on the upper lid of the molten metal holding furnace. The surface combustion burner includes a combustion surface and a premixed gas chamber behind the combustion surface, and a premixed gas supply pipe is connected to the premixed gas chamber. Then, the premixed gas is introduced into the premixed gas chamber from the premixed gas supply pipe and burned on the surface of the combustion surface, and the molten metal is heated by the heat of the high-temperature combustion exhaust gas generated thereby and the radiant heat from the surface of the combustion surface. The molten metal in the room is heated and maintained at a predetermined temperature.

  The molten metal holding furnace disclosed in Patent Document 1 can reduce the oxidation loss of the molten metal and improve the molten metal yield with simple equipment. Since the surface combustion burner disclosed in Patent Document 1 is parallel to the surface to be heated at the upper part of the molten metal and the separation distance is reduced and radiant heat transfer is performed, the molten metal can be heated with good heat transfer efficiency.

Utility Model Registration No. 3111330

  However, the surface combustion burner disclosed in Patent Document 1 has a problem in that maintenance of members near the combustion surface must be performed frequently. The cause is that the gas is burned not only in the original combustion surface but also in the interior due to radiant heat received from the outside of the burner. When the gas burns in such a manner, the gas burns both on the original combustion surface and in the interior thereof, so that the durability of the members near the combustion surface is greatly reduced. Such a phenomenon is called “backfire”.

  The present invention has been made to solve the above-described problems. The object is to provide an in-container heating burner that can improve the durability of members near the combustion surface by preventing backfire.

  In order to achieve the above object, according to one aspect of the present invention, the in-container heating burner 20 is connected to the gas supply device 22 and attached to the mouth of the container 24. The in-container heating burner 20 includes a gas passage part 30, a gas ejection part 32, a metal knit 34 in contact with the surface of the gas ejection part 32, and a connection part 36. The gas supplied from the gas supply device 22 passes through the gas passage unit 30. The gas ejection part 32 is connected to the gas passage part 30 and is hollow. The connection part 36 is connected to the container 24 so that the gas ejection part 32 and the metal knit 34 face the inner surface of the container 24. In addition, the gas ejection part 32 has a plurality of gas ejection holes 50. The plurality of gas ejection holes 50 are covered with the metal knit 34. The metal knit 34 is spot welded to the gas ejection part 32 at the joint between the gas passage part 30 and the gas ejection part 32.

  The in-container heating burner according to the present invention can improve the durability of members near the combustion surface by preventing backfire.

It is a conceptual diagram which shows the structure of the burner system concerning embodiment of this invention. It is sectional drawing shown in the state in which the burner concerning embodiment of this invention was attached to the ladle. It is a top view of the burner concerning the embodiment of the present invention. It is sectional drawing which shows the front-end | tip part of the burner concerning embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[Description of configuration]
FIG. 1 is a conceptual diagram showing a configuration of a burner system according to the present embodiment. FIG. 2 is a cross-sectional view showing the in-container heating burner 20 according to the present embodiment attached to the ladle 24 according to the present embodiment. FIG. 3 is a plan view of the burner according to the present embodiment. FIG. 4 is a cross-sectional view showing the tip portion of the burner according to the present embodiment.

  The burner system according to this embodiment includes an in-container heating burner 20 and a gas supply device 22. The in-container heating burner 20 is attached to the ladle 24 and heats the inside thereof to evaporate water. The gas supply device 22 is connected to the in-container heating burner 20 and supplies a mixed gas of combustible gas and oxygen to the in-container heating burner 20. However, this mixed gas contains air in addition to combustible gas and oxygen.

  The configuration of the in-container heating burner 20 will be described with reference to FIGS. The in-container heating burner 20 according to the present embodiment includes a gas passage part 30, a gas ejection part 32, a metal knit 34, a connection part 36, a heat insulating material 38, a pilot burner 42, an inspection window 44, And an exhaust pipe 46.

  The gas passage unit 30 is connected to the main gas pipe 220 of the gas supply device 22 and allows the mixed gas supplied by the gas supply device 22 to pass therethrough. The gas ejection part 32 is a part from which the mixed gas that has passed through the gas passage part 30 is ejected. The gas ejection part 32 according to the present embodiment is cut out from a lump of stainless steel and is hollow. The metal knit 34 is in contact with the surface of the gas ejection part 32. The metal knit 34 is a metal cloth. The metal knit 34 according to the present embodiment is manufactured by using a metal thread as a material and the same manufacturing method as a cloth used for clothing. This metal thread is manufactured by a manufacturing method similar to that used for clothing using heat-resistant metal fibers as a material. The connection part 36 is a member for connecting the gas passage part 30 to the ladle 24. The heat insulating material 38 is a member for preventing the mixed gas passing through the gas passage portion 30 from being heated. Without the heat insulating material 38, the mixed gas is heated by the radiant heat radiated from the inside of the ladle 24. This raises the temperature of the mixed gas, which causes the mixed gas to ignite inside the gas ejection portion 32. In order to prevent such a situation, a heat insulating material 38 is attached. The pilot burner 42 is connected to the sub gas pipe 222 of the gas supply device 22. The pilot burner 42 is an ignition device for starting combustion within the container heating burner 20. The observation window 44 is for determining whether or not the combustion is continued inside the ladle 24. The exhaust cylinder 46 is a cylinder for discharging carbon dioxide and the like generated as a result of combustion inside the ladle 24.

  As shown in FIG. 4, in the present embodiment, a gas ejection hole 50 is provided in the gas ejection portion 32. The aforementioned mixed gas is ejected from the gas ejection hole 50. As is clear from FIG. 4, the gas ejection portion 32 has a frustum-shaped portion 52 and a cylindrical portion 54. The “frustum shape” means the shape of the latter part when the cone is cut along a plane parallel to the bottom surface and separated into small cones and other parts. Both the frustum-shaped part 52 and the cylindrical part 54 are provided with gas ejection holes 50.

  The metal knit 34 described above covers the gas ejection holes 50. When this embodiment is described more precisely, the metal knit 34 covers almost the entire gas ejection portion 32 and therefore covers the gas ejection holes 50. Although FIG. 2 shows a state in which a part has been removed, the metal knit 34 in the present embodiment covers almost the entire gas ejection portion 32. The metal knit 34 is spot welded to the gas ejection part 32 at the joint 60 between the gas passage part 30 and the gas ejection part 32.

  The configuration of the gas supply device 22 is well known. Therefore, detailed description thereof will not be repeated here.

  Next, the configuration of the ladle 24 according to the present embodiment will be described with reference to FIG. The ladle 24 according to this embodiment includes a burner mounting part 70, a molten metal storage part 72, and a pouring part 74. The above-described in-container heating burner 20 is attached to the burner attaching portion 70. The molten metal storage portion 72 stores the molten metal. The molten metal is discharged from the pouring part 74 when the ladle 24 according to the present embodiment is tilted.

  The burner mounting part 70 has an installation base part 80 and a connection part 82. The connection part 36 of the in-container heating burner 20 is placed on the installation table 80 and fixed. There is a hole in the center of the installation table 80. The gas passage part 30 penetrates the hole. The connection part 82 is connected to the molten metal storage part 72.

  The molten metal storage portion 72 includes an inner wall layer 90, a fireproof layer 92, a heat insulating layer 94, an outer shell layer 96, and a surface coating layer 98. The inner wall layer 90 forms the inner peripheral surface of the molten metal storage portion 72. The refractory layer 92 is disposed so as to surround the inner wall layer 90. The heat insulating layer 94 is disposed so as to surround the refractory layer 92. The outer shell layer 96 covers the surface of the heat insulating layer 94. In the present embodiment, the outer shell layer 96 is made of a steel plate. The surface covering layer 98 is attached to the surface of the outer shell layer 96. The surface coating layer 98 is formed of, for example, a heat insulating material described below. The heat insulating material includes an aggregate and a binder. If necessary, the heat insulating material further includes a dispersion medium. In the present invention, the weight percent of the aggregate and the binder is not particularly limited. The pouring part 74 protrudes from the side surface of the molten metal storage part 72. The pouring part 74 is cylindrical.

  The heat insulating material forming the surface coating layer 98 will be described below. The aggregate referred to in the present embodiment is a component having a function of maintaining the form of the surface coating layer 98. The kind of aggregate is not particularly limited. Moreover, the binding material referred to in the present embodiment refers to a substance having an action of binding aggregates. If it has the effect | action which couple | bonds aggregates, the kind, form, and density | concentration of a binder will not be specifically limited. Examples of aggregates, binders, and dispersion media include those shown in Table 1.

  Therefore, examples of the heat insulating material according to this embodiment include those shown in Table 2.

  The heat insulating material according to the present embodiment is manufactured by kneading an aggregate, a binder, and a dispersion medium. The specific procedure of the kneading is not particularly limited. For example, the heat insulating material according to the present embodiment is manufactured by kneading an aggregate, a binder, and a dispersion medium with a known kneader. This heat insulating material should just cover the surface of the thing which should be insulated. A thickness of 1 millimeter is sufficient, but is not limited to this. This heat insulating material cannot be used only for the ladle 24. For example, it can be used on the surface of a structure, such as a soot, an industrial furnace, an incinerator, or a boiler, which can transfer heat to the outside.

  The formation method of the surface coating layer 98 concerning this embodiment is not specifically limited. For example, the surface coating layer 98 according to the present embodiment is formed by spraying the above-described heat insulating material onto the outer shell layer 96 by a known spraying device. The heat insulating material sprayed and dried on the outer shell layer 96 becomes the surface covering layer 98. Incidentally, when the heat insulating material according to the present embodiment is used on the surface of a structure other than the ladle 24, the formation method may be the same as the method for forming the surface coating layer 98 according to the present embodiment.

[Description of operation]
Next, the operation of the burner system according to this embodiment will be described. It is assumed that the in-container heating burner 20 is attached to the ladle 24 and the gas supply device 22 is activated. The activated gas supply device 22 supplies a mixed gas from the auxiliary gas pipe 222 and ignites the pilot burner 42. The gas passage part 30 allows the mixed gas supplied from the main gas pipe 220 to pass through. The mixed gas that has passed through the gas passage part 30 is ejected at the gas ejection part 32 and leaks out of the metal knit 34. The mixed gas leaking out of the metal knit 34 ignites the flame of the pilot burner 42 and starts combustion.

  When the flame of the pilot burner 42 is ignited by the mixed gas ejected from the gas ejection part 32, the flame spreads over the entire metal knit 34. After the flame ignites, the gas ejection part 32 continues to eject the mixed gas. After the flame spreads, the temperature of the metal knit 34 gradually increases due to the flame. As a result, the metal knit 34 emits infrared rays. The inside of the ladle 24 is heated by the flame on the surface of the metal knit 34 and this infrared ray, and the water adhering thereto becomes water vapor. This steam is discharged from the exhaust tube 46 together with carbon dioxide.

  When the inside of the ladle 24 is sufficiently heated, infrared rays also begin to be emitted from the inside of the ladle 24. The infrared rays reach the metal knit 34. When infrared rays reach the metal knit 34, the temperature of the metal knit 34 rises. However, since the metal knit 34 is in contact with the gas ejection portion 32, the mixed gas protruding from the gas ejection hole 50 is immediately discharged out of the metal knit 34 and burns there. There is almost no gas burning inside the metal knit 34. Needless to say, the mixed gas does not burn in the gas ejection portion 32. As a result, backfire is prevented.

  On the other hand, the inner wall layer 90 of the ladle 24 receives heat by being heated by the burner system according to the present embodiment. The heat is transmitted to the refractory layer 92. The heat transferred to the refractory layer 92 is transferred to the heat insulating layer 94. The heat transferred to the heat insulating layer 94 is transferred to the outer shell layer 96. The heat transferred to the outer shell layer 96 is transferred to the surface coating layer 98. The heat transferred to the surface coating layer 98 is transferred to the outside of the ladle 24 through air. The temperature of the surface coating layer 98 varies depending on the composition of the heat insulating material that is the material of the surface coating layer 98. This is the same even if the heat applied to the inner wall layer 90 of the ladle 24 by the burner system according to the present embodiment is constant. In the following, examples and comparative examples that support the temperature will be described.

  The heat insulating material according to Examples 1 to 3 was prepared by mixing the aggregate and the binder in the container. Moreover, the heat insulating material concerning a comparative example was prepared by mixing only the component used as a binder in a container. Table 3 shows the formulations in Examples 1 to 3 and Comparative Examples. Moreover, the components of the aggregate in Examples 1 to 3 are as shown in Table 4.

  After the insulation was prepared, the insulation was sprayed onto the steel plate. The types and thicknesses of the steel plates are as shown in Table 3. After spraying, the thickness of the sprayed insulation was measured. For the measurement of thickness, Harry Digital, a film thickness meter manufactured by Sado Cow Industry Co., Ltd., was used. The thickness of the sprayed insulation is as shown in Table 3. The steel plate sprayed with insulation was left unattended. The time allowed to stand is as shown in Table 3. By this standing, the heat insulating material was naturally dried. The steel plate corresponds to the outer shell layer 96 described above. The naturally dried heat insulating material corresponds to the surface coating layer 98. After the heat insulating material was naturally dried, a sample was taken from the heat insulating material, and the moisture content of the sample was measured. A heat drying moisture meter ML-50 manufactured by A & D Co., Ltd. was used to measure the moisture content. The moisture content measured in this way is “the moisture content of the heat insulating material after natural drying”. The measured moisture content is shown in Table 3. After measuring the moisture content, the steel plate was placed on a pair of struts. The dried insulation was placed on the upper side of the steel plate. Under the steel plate, a Sbankan infrared burner manufactured by Rinnai Corporation was installed. The steel plate was heated by the Schwank gas infrared burner. Table 3 shows the distance from the Schwann gas infrared burner to the steel sheet and the temperature at the start of heating. Simultaneously with the start of heating, the temperature between the steel sheet and the spray layer and the surface temperature of the spray layer were measured successively. A temperature high tester 3441 manufactured by Hioki Electric Co., Ltd. was used for these temperature measurements. Two temperatures (one of which is referred to as “A point” and the other is referred to as “B point”) between the steel plate and the heat insulating material, and two locations on the heat insulating material surface (two points) One of which is called “C point” and the other is called “D point”). The temperature between the steel plate and the heat insulating material was measured by fixing the probe to the surface of the steel plate before spraying the heat insulating material and connecting the probe to the temperature high tester 3441 described above. The temperature on the surface of the heat insulating material was measured by fixing the probe to the surface of the heat insulating material after natural drying of the heat insulating material and connecting the probe to the temperature high tester 3441 described above. A PC card type temperature data collection system NR-250 manufactured by Keyence Corporation was used for recording these temperatures. The heating time is as shown in Table 3. This heating time was set based on an approximate time until the temperature of the steel plate reached from normal temperature to 100 ° C. After the temperature was measured, an average value of the temperature at the point A and the temperature at the point B when the heating time shown in Table 3 elapsed from the start of heating was calculated. The average value of the surface temperature at point C and the surface temperature at point D at the time when the heating time shown in Table 3 had elapsed from the start of heating was also calculated. After these average values were calculated, the difference between these average values was also calculated. These values are as shown in Table 5. Table 5 also shows changes in the surface of the heat insulating material before the start of heating and after the end of heating.

  As is apparent from Table 5, in the case of Example 1 and Example 2, the difference in the average value of the temperatures is greater depending on the presence or absence of the heat insulating material than in Example 3 and the comparative example. In particular, in the case of Example 2, the difference in the average temperature value is large. This indicates that the binding material not included in Example 1 but included in Example 2 has a great influence on the difference in average temperature value. On the other hand, in the case of Example 3 and the comparative example, there is almost no difference in the average value of temperature regardless of the presence or absence of the heat insulating material. That is, conventionally, a high temperature structure such as a ladle and a molten metal holding furnace has a problem that the temperature around the structure becomes high. This is because the heat inside such a high-temperature structure is transmitted to the outside. The heat insulating material according to Example 1 and the heat insulating material according to Example 2 are more effective than the heat insulating material according to Example 3 and the heat insulating material according to the comparative example that the heat inside the structure is transmitted to the outside. Can be suppressed. In particular, since the heat insulating material according to the second embodiment includes the binder not included in the first embodiment, the heat inside the structure can be more effectively suppressed from being transmitted to the outside.

[Effect of the burner system according to this embodiment]
As described above, the burner system according to this embodiment heats the inside of the ladle 24 while preventing backfire. Since the inside of the ladle 24 is heated to a temperature similar to that of the molten metal in this way, even if the molten metal is injected into the ladle 24, it is not necessary to receive a large heat shock.

DESCRIPTION OF SYMBOLS 20 ... Burner 22 for heating in a container ... Gas supply device 24 ... Ladle 30 ... Gas passage part 32 ... Gas ejection part 34 ... Metal knit 36 ... Connection part 38 ... Heat insulating material 42 ... Pilot burner 44 ... Peep window 46 ... Exhaust pipe DESCRIPTION OF SYMBOLS 50 ... Gas ejection hole 52 ... Frustum-shaped part 54 ... Cylindrical part 60 ... Joining part 70 ... Burner attachment part 72 ... Molten metal accommodating part 74 ... Pouring part 80 ... Installation base part 82 ... Connection part 90 ... Inner wall layer 92 Refractory layer 94 Thermal insulation layer 96 Outer shell layer 98 Surface coating layer 220 Main gas pipe 222 Sub-gas pipe

Claims (1)

A burner for heating in a container connected to a gas supply device and attached to the mouth of the container,
A gas passage part through which the gas supplied by the gas supply device passes,
A hollow gas ejection part connected to the gas passage part;
A metal knit in contact with the surface of the gas ejection part;
A connection part for connecting the gas ejection part and the metal knit so as to face the inner surface of the container;
The gas ejection part has a plurality of gas ejection holes,
The plurality of gas ejection holes are covered with the metal knit,
The burner for heating in a container, wherein the metal knit is spot welded to the gas ejection portion at a joint portion between the gas passage portion and the gas ejection portion.

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