JP6255643B2 - Powder melting burner - Google Patents

Description

  The present invention relates to a powder melting burner.

  When melting an inorganic powder raw material such as silica, alumina or glass raw material powder, a high-temperature flame is required, and therefore an oxygen / gas combustion burner is usually used. This burner includes a premixed burner and a diffusion burner.

  The premixed burner is a mixture of oxygen and combustion gas that is pre-mixed and ejected to the combustion field. In the burner, the raw material powder, oxygen, and fuel are thoroughly mixed and formed in the flame formed at the burner tip. What supplies raw material powder is known (for example, patent document 1).

  A diffusion burner is one in which oxygen and combustion gas are separately ejected and mixed in a combustion field. For example, a diffusion burner disposed in a saddle type path is composed of a concentric double tube, Many small pipes are provided between the inner pipe and the outer pipe, and the siliceous raw material is allowed to flow naturally (or under pressurized flow) from the central pipe (inner pipe) of the burner. Combustible gas from the small pipe and oxygen gas from the outer pipe In a known method, a raw material is introduced into a flame formed by the above process to produce fused silica spheres (for example, Patent Document 2).

  Further, as another diffusion burner, it is composed of concentric quintuple pipes, supplying raw material powder to the combustion chamber using oxygen gas or oxygen-enriched gas as a carrier gas from the center, and fuel gas from its outer periphery, Further, it is known that primary oxygen and secondary oxygen are supplied from the outer periphery, and a cooling jacket for cooling the burner is provided at the outermost periphery (for example, Patent Documents 3 and 4).

  Furthermore, a burner structure has also been proposed that increases the melting efficiency by providing a fuel supply path and jet holes inside and outside the raw material powder supply path and jet holes, and sandwiching the flow of the raw material with a flame (for example, Patent Document 5).

JP 62-241543 A JP 58-145613 A Japanese Patent No. 3331491 Japanese Patent No. 3322228 Japanese Patent No. 5291748

  By the way, since the conventional burner described above is used by being installed in a high-temperature furnace in order to exert its performance, it is necessary to provide a cooling jacket so as to surround the burner nozzle, and a coolant (refrigerant) for this cooling jacket. In general, cooling water is used.

  However, in the conventional cooling jacket, condensation occurs at the tip of the cooling jacket, and the raw material blown from the burner adheres and grows there, which not only inhibits the combustion state of the burner but also affects the product quality. There was a problem that there is a risk of giving.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the powder melting burner which prevents generation | occurrence | production of dew condensation and reduces adhesion of a raw material.

In order to solve this problem, the present invention has the following configuration.
That is, the invention according to claim 1 is a powder melting burner provided with a cooling means for cooling the burner nozzle, the raw material powder supply path for supplying the raw material powder, and the raw material powder in the raw material powder supply path A raw material powder supply device to be supplied; a raw material injection hole provided at the front end of the raw material powder supply path; a fuel supply path for supplying fuel; a fuel injection hole provided at the front end of the fuel supply path; A combustion-supporting gas supply path for supplying oxygen-enriched air; and a combustion-supporting gas injection hole provided at a tip of the combustion-supporting gas supply path. a cooling gas flow path having a section, and a temperature control means for controlling the surface temperature of the cooling means to a required temperature, Ri cooling structure der with the cooling gas to the raw material powder supply unit from the outlet section A powder melting burner to be supplied .

  The invention according to claim 2 is characterized in that the temperature control means is a temperature measurement means for measuring the temperature of the cooling gas on the derivation portion side, a flow rate control means for controlling the flow rate of the cooling gas introduced into the introduction portion, It is a powder melting burner of Claim 1 which has these.

  The invention according to claim 3 is the powder melting burner according to claim 1 or 2, wherein the cooling means is provided at an outermost peripheral portion of the burner nozzle.

  The invention according to claim 4 is the powder melting burner according to any one of claims 1 to 3, wherein the cooling means is provided so as to surround the burner nozzle.

  The invention according to claim 5 is the powder melting burner according to any one of claims 1 to 4, wherein the cooling gas includes a combustion-supporting gas.

The invention according to claim 6 includes a combustion-supporting gas mixer that supplies a combustion-supporting gas to the combustion-supporting gas supply path, and supplies a cooling gas from the lead-out portion to the combustion-supporting gas mixer. The powder melting burner according to any one of claims 1 to 5.

  The powder melting burner of the present invention has an air cooling structure in which the cooling means for cooling the burner nozzle has a temperature control means for controlling the surface temperature of the cooling means to a required temperature while using a cooling gas as a refrigerant. Since the surface temperature can be controlled and maintained at a temperature higher than the temperature at which condensed water does not adhere, it is possible to prevent the occurrence of condensation on the surface of the burner nozzle and reduce the adhesion of raw materials. Therefore, the combustion state of the burner can be kept good, and the problem that the adhering matter is mixed in the product and the quality is deteriorated can be solved.

It is an expanded sectional view showing the structure of the powder fusion burner which is one embodiment to which the present invention is applied. It is a systematic diagram which shows the temperature control means of the powder melting burner which is one Embodiment to which this invention is applied. It is a systematic diagram which shows an example of the utilization form of the cooling gas in the powder melting burner which is one Embodiment to which this invention is applied. It is a systematic diagram which shows the other example of the utilization supply form of the cooling gas in the powder melting burner which is one Embodiment to which this invention is applied.

  Hereinafter, a powder melting burner which is an embodiment to which the present invention is applied will be described in detail with reference to the drawings. In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent.

First, the structure of the powder melting burner which is one embodiment to which the present invention is applied will be described.
1 and 2 show a powder melting burner (hereinafter, simply referred to as “burner”) as an embodiment to which the present invention is applied, and FIG. 1 is cut along the central axis of the burner. FIG. 2 is a system diagram schematically showing the temperature control means of the burner.

  As shown in FIG. 1, the burner 1 of the present embodiment includes a raw material powder supply pipe 2 that supplies raw material powder, a fuel supply pipe 3 that supplies fuel, and oxygen or oxygen enrichment from the center side of the burner 1. Concentric, comprising a first support gas supply pipe 4 for supplying air, a second support gas supply pipe 5 for supplying oxygen or oxygen-enriched air, and a cooling jacket (cooling means) 6 having an air cooling structure. It has a multi-tube structure. Moreover, the burner 1 of this embodiment is an oxyfuel combustion burner using fuel gas and a combustion-supporting gas containing oxygen.

  The raw material powder supply pipe 2 is provided on the innermost side of the concentric multiple pipe structure of the burner 1 along the axial direction of the burner 1. The space inside the raw material powder supply pipe 2 is a raw material powder supply path 2A, which can supply a mixture of the raw material powder and the carrier gas.

  The front end of the raw material powder supply path 2 </ b> A is open to the front end surface 1 a of the burner 1. And the opening part of this raw material powder supply pipe | tube 2 becomes the raw material ejection hole 2a, and material powder is ejected in the direction inclined outside with respect to the burner central axis. The raw material powder supply pipe 2 is connected to a raw material powder feeder (reference numeral 10 shown in FIG. 3) for supplying the raw material powder together with the carrier gas.

  The raw material powder is not particularly limited, and specific examples include inorganic powder raw materials such as silica, alumina or glass raw material powder. The particle form of the raw material powder is not particularly limited, and may be non-spherical particles having corners or spherical particles having no corners.

  The particle diameter of the raw material powder is not particularly limited, but is preferably in the range of 10 to 100 μm, and more preferably in the range of 20 to 30 μm. Here, it is preferable that the particle diameter of the raw material powder is within the above range because it is easy to store and can be sufficiently melted.

  The carrier gas is not particularly limited as long as it is a gas capable of conveying the raw material powder. Specifically, for example, in consideration of safety, an inert gas such as nitrogen gas or argon gas can be used as the carrier gas. In addition, when the raw material powder has a large particle size or when combustion in an oxidizing atmosphere is slow, it is preferable to use a combustion-supporting gas containing oxygen such as air or oxygen-enriched air.

  The fuel supply pipe 3 is provided outside the raw material powder supply pipe 2 and coaxially with the raw material powder supply pipe 2. Further, a space provided between the fuel supply pipe 3 and the raw material powder supply pipe 2 is a fuel supply path 3A, which can supply fuel gas. In other words, the fuel supply path 3A is provided on the outer periphery of the raw material powder supply path 2A.

  The tip of the fuel supply path 3 </ b> A is open to the tip surface 1 a of the burner 1. As shown in FIG. 1, the opening of the fuel supply pipe 3 serves as a fuel supply hole 3 a, and jets fuel gas in a direction parallel to the burner central axis.

The fuel gas is not particularly limited, and specifically, for example, gaseous fuel such as methane (CH ₄ ) or propane (C ₃ H ₈ ) can be used. Further, if a fuel atomization mechanism is provided in the fuel supply pipe 3, liquid fuel such as kerosene and alcohol can be used.

  The first combustion-supporting gas supply pipe 4 is provided outside the fuel supply pipe 3 coaxially with the raw material powder supply pipe 2 and the fuel supply pipe 3. Moreover, the space provided between the fuel supply pipe 3 and the first combustion-supporting gas supply pipe 4 serves as the first combustion-supporting gas supply path 4A and can supply combustion-supporting gas. . In other words, the first combustion-supporting gas supply pipe 4A is provided on the outer periphery of the fuel supply path 3A.

  The front end of the first combustion-supporting gas supply path 4 </ b> A is open to the front end surface 1 a of the burner 1. The opening of the first combustion-supporting gas supply path 4A is a first combustion-supporting gas supply hole 4a so that the combustion-supporting gas is ejected in a direction perpendicular to the burner central axis. It has become.

  The second flammable gas supply pipe 5 is provided outside the first flammable gas supply pipe 4 and coaxially with the raw material powder supply pipe 2, the fuel supply pipe 3 and the first flammable gas supply pipe 4. It has been. In addition, the space provided between the first support gas supply pipe 4 and the second support gas supply pipe 5 is a second support gas supply path 5A, and the support gas is supplied. Supply is possible. In other words, the second combustion-supporting gas supply pipe 5A is provided on the outer periphery of the first combustion-supporting gas supply pipe 4A.

  The tip of the second combustion-supporting gas supply path 5 </ b> A is open to the tip surface 1 a of the burner 1. The opening of the second combustion-supporting gas supply path 5A is a second combustion-supporting gas supply hole 5a so that the combustion-supporting gas is ejected in a direction horizontal to the burner central axis. It has become.

  The combustion-supporting gas supplied to the first combustion-supporting gas supply path 4A and the second combustion-supporting gas supply path 5A is particularly limited as long as it can form a flame atmosphere by reacting with the fuel gas. It is not a thing. Specifically, for example, oxygen or oxygen-enriched air can be used as such a combustion-supporting gas.

  The cooling jacket 6 is a cooling means having an air cooling structure that cools while controlling and maintaining the surface temperature of the burner 1 to a temperature at which condensed water does not adhere (for example, 100 ° C.) or higher. As shown in FIG. 1, the cooling jacket 6 is formed on the outermost peripheral portion of the burner nozzle composed of the raw material powder supply pipe 2, the fuel supply pipe 3, and the first and second combustion-supporting gas supply pipes 4 and 5. It is provided so as to surround the burner nozzle.

  As shown in FIGS. 1 and 2, the cooling jacket 6 has a cooling gas flow path 6A having a cooling gas introduction portion 6a and a derivation portion 6b, and a temperature for controlling the surface temperature of the burner 1 to a required temperature. And a control unit (temperature control means) 6B.

  As shown in FIG. 1, the cooling gas passage 6 </ b> A is provided inside the cooling jacket 6. Specifically, the cooling gas flow path 6A has a double pipe structure, and the introduction portion 6a is provided at the base end side of the flow path on the inner peripheral side (that is, the second combustion-supporting gas supply path 5A side). Lead-out portions 6b are respectively provided on the base end side of the outer peripheral flow path (that is, the surface side of the burner 1). The inner peripheral flow path and the outer peripheral flow path are communicated with each other on the tip end side of the burner 1.

  According to the burner 1 of the present embodiment, a relatively low temperature cooling gas supplied from a cooling gas supply source (not shown) is transferred from the introduction portion 6a side to the inner peripheral flow path of the cooling gas flow path 6A. Since it can be introduced, the burner nozzle part can be protected from radiant heat from the furnace and radiant heat from the furnace body. Thereby, it can prevent that a burner nozzle part overheats and melts down.

  Moreover, since the relatively high temperature cooling gas after cooling the burner nozzle part provided inside the cooling jacket 6 flows in the flow path on the outer peripheral side of the cooling gas flow path 6A, the surface of the burner 1 It can prevent that temperature falls excessively.

  By the way, in the conventional water-cooling type cooling jacket, the cooling jacket interior is simple considering the pressure loss of the cooling water and the blockage of the cooling jacket flow path due to the precipitation of impurities (calcium, silica, etc.) contained in the cooling water. Generally, a multi-tube structure is used.

  On the other hand, the cooling jacket 6 of the air-cooling structure in the burner 1 of this embodiment can have the same flow path structure as the water-cooling cooling jacket.

  However, since the impurities contained in the cooling gas used as the refrigerant are extremely small compared to the cooling water, there is little fear of performance degradation due to precipitation of impurities. Further, since the cooling gas has a small pressure loss with the same pipe diameter as compared with the case where the cooling water is used as the refrigerant, in order to improve the cooling efficiency in the cooling jacket 6, the inside of the cooling gas channel 6A (in particular, It is preferable to improve the cooling efficiency by providing a radiator fin or the like in the inner peripheral flow path).

  As shown in FIG. 2, the cooling jacket 6 in the burner 1 of the present embodiment is connected to the introduction part 6a of the cooling gas channel 6A and the cooling gas introduction path L2 to the introduction part 6b. Has been.

  The cooling gas introduction path L1 is a pipe provided for supplying a cooling gas from a cooling gas supply source (not shown) to the cooling gas passage 6A via the introduction portion 6a. The cooling gas introduction path L1 is provided with a flow rate control valve (flow rate control means) 7 for adjusting the flow rate of the cooling gas. By adjusting the opening degree of the flow control valve 7, the flow rate of the cooling gas introduced into the cooling gas channel 6A can be adjusted.

  The cooling gas lead-out path L2 is a pipe provided for conveying the cooling gas discharged from the cooling gas flow path 6A via the lead-out part 6b. In addition, a thermometer (temperature measuring means) 8 for measuring the temperature of the cooling gas is provided on the deriving portion 6b side of the cooling gas deriving path L2.

  Here, as shown in FIG. 2, the temperature control unit 6 </ b> B is configured to include the above-described thermometer 8, the flow rate control valve 7, and a temperature indicating controller (TIC) 9. .

  According to the cooling jacket 6 in the burner 1 of the present embodiment, when the cooling gas passage 6A is circulated, the temperature control unit 6B, that is, the temperature of the cooling gas discharged from the cooling gas passage 6A is measured by the thermometer 8. The flow rate of the cooling gas can be adjusted by controlling the opening degree of the flow rate control valve 8 by the temperature indicating controller 9 while monitoring. Therefore, the capability of the cooling jacket 6 can be maintained in an optimum state so that condensation does not occur on the surface of the burner 1.

  The cooling gas supplied to the cooling jacket 6 is not particularly limited as long as it can protect the burner nozzle portion from radiant heat from the inside of the furnace and radiant heat from the furnace body. As such a cooling gas, specifically, an inert gas such as nitrogen gas or argon gas can be used. Further, like the carrier gas, a combustion-supporting gas containing oxygen such as air or oxygen-enriched air may be used.

  According to the burner 1 of the present embodiment, the cooling jacket 6 that cools the burner nozzle uses the temperature control unit 6B that uses the cooling gas as a refrigerant and controls the surface temperature of the burner 1 (that is, the cooling jacket 6) to a required temperature. It has an air cooling structure, and the surface temperature of the burner 1 can be controlled and maintained at a temperature at which condensed water does not adhere (for example, 100 ° C.) or higher. Thereby, generation | occurrence | production of dew condensation on the surface of a burner nozzle can be prevented, and adhesion of a raw material can be reduced. Therefore, the combustion state of the burner 1 can be maintained well, and the problem that the adhering matter is mixed in the product and the quality is deteriorated can be solved.

Moreover, according to the burner 1 of this embodiment, the exhaust heat of the cooling gas derived | led-out from the cooling jacket 6 can be utilized.
FIG. 3 is a system diagram illustrating an example of a usage pattern of the cooling gas in the burner 1 of the present embodiment. In addition, in this usage pattern, about the same structure as the structure of the burner 1 mentioned above, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 3, the cooling gas led out from the lead-out part 6b of the cooling jacket 6 is supplied to the raw material powder feeder 10 via the cooling gas lead-out path L2. Here, the raw material powder feeder 10 is an apparatus for supplying a mixed gas of the raw material powder and the carrier gas to the raw material powder supply path 2A. Further, the raw material powder feeder 10 includes a path L3 for supplying carrier gas from a carrier gas supply source (not shown), a path L4 for supplying mixed gas to the raw material powder supply path 2A, and a carrier. A path L5 for discharging the gas out of the system is connected. Further, a flow meter 11 is provided in the cooling gas introduction path L1, a flow control valve 12 and a flow meter 13 are provided in the path L3, and a flow control valve 14 and a flow meter 15 are provided in the path L5, respectively.

  In this usage mode, the same gas as the carrier gas is used as the cooling gas. As a result, the preheated cooling gas led out from the lead-out portion 6b of the cooling jacket 6 is supplied to the raw material powder feeder 10 via the cooling gas lead-out path L2, and the raw material powder together with the raw material powder as a carrier gas. It can be supplied to the raw material powder supply path 2A.

  Here, the cooling gas (carrier gas) discharged from the cooling jacket 6 is controlled to an appropriate flow rate so that the performance of the cooling jacket 6 can be maintained. This flow rate may not coincide with an appropriate flow rate of the carrier gas for conveying the raw material powder, and in this case, there is a problem that the raw material powder cannot be conveyed properly.

  Therefore, when the flow rate control valve and the flow meter provided in each path are controlled by the flow rate indicating controller 16, the path L5 when the flow rate of the cooling gas discharged from the cooling jacket 6 is larger than the appropriate flow rate of the carrier gas. A part of the gas is discharged into the atmosphere, and when it is insufficient, the flow rate is corrected by adding a carrier gas at room temperature through the path L3.

  As described above, according to this mode of use, the cooling gas discharged from the cooling jacket 6 is used as a carrier gas, and after being supplied to the raw material powder feeder 10, the raw material powder is partially discharged and replenished. The raw material powder can be preheated efficiently in the body feeder 10.

  FIG. 4 is a system diagram showing another example of the usage form of the cooling gas in the burner 1 of the present embodiment. In addition, in this usage pattern, about the same structure as an example of the usage pattern mentioned above, the same code | symbol is attached and description is abbreviate | omitted.

As shown in FIG. 4, in this usage mode, a combustion-supporting gas mixer 17 is provided instead of the raw material powder supply device 10, and it is supported instead of the path L <b> 4 connected to the raw material powder supply passage 2 </ b> A. A path L6 connected to the flammable gas supply paths 4A and 4B is provided. Incidentally, the route L6 is branched into a path L6A and L6B the burner 1 side, the first and second supporting-retardant gas supply passage 4A, respectively, are connected to 5A.

  In this usage mode, the cooling gas uses the same component gas as the combustion-supporting gas. As a result, the preheated cooling gas led out from the lead-out portion 6b of the cooling jacket 6 is supplied to the combustion support gas mixer 17 via the cooling gas lead-out path L2, and the first burner 1 of the burner 1 is used as the combustion support gas. The first and second combustion-supporting gas supply paths 4A and 5A can be supplied respectively.

  In the case of this usage mode, the flow rate of the cooling gas discharged from the cooling gas supply path 6A may not match the flow rate of the combustion-supporting gas necessary for combustion, as in the case of using the carrier gas. . Here, if there is an excess or deficiency in the combustion-supporting gas for combustion, the combustion state of the burner 1 cannot be maintained properly, so the flow rate of the discharged cooling gas is higher than the proper flow rate of the combustion-supporting gas. If there is too much, a part of the gas is discharged from the path L5 to the atmosphere, and if insufficient, the flow rate correction is performed by adding a combustion-supporting gas at room temperature from the path L3.

  According to this form of use, the cooling gas discharged from the cooling jacket 6 can be used as a preheated combustion-supporting gas. Thus, when the combustion-supporting gas for combustion is preheated, the combustibility of the fuel is improved and incomplete combustion can be suppressed. As a result, for example, it is possible to prevent a problem that carbon generated by incomplete combustion of the fuel is mixed into the product.

  As described above, according to the burner (powder melting burner) 1 of the present embodiment, the cooling jacket 6 having an air cooling structure is used to cool and protect the burner ejection holes (nozzles). In comparison, there is no worry of cooling water leakage.

  Further, by using a cooling gas as the refrigerant and measuring and controlling the temperature, the surface temperature of the cooling jacket 6 (that is, the surface temperature of the burner 1) is set to a temperature that is not higher than that at which condensed water does not adhere (for example, 100 ° C. or higher). ) Can be easily held. For this reason, no condensation occurs at the tip of the cooling jacket 6, so that the raw material powder can be prevented from adhering, melting and growing. Therefore, the combustion state of the burner 1 is kept good, and the problem that the adhering matter is mixed in the product and the quality is deteriorated is solved.

  Further, in the burner 1 of the present embodiment, when a combustion-supporting gas is used as the cooling gas, the combustion-supporting gas whose temperature has been increased by heat exchange in the cooling jacket is replaced with a combustion support gas for raw material conveyance, or By using it as a combustion-supporting gas for fuel combustion or both, it is possible to improve the melting efficiency by preheating the raw material powder and to improve the burner combustion efficiency by increasing the temperature of the combustion-supporting gas.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the configuration of the burner 1 of the embodiment described above is an example, and the number and arrangement order of the raw material powder supply, the fuel supply path, and the combustion-supporting gas supply path are not particularly limited. Further, the direction of each ejection hole is not particularly limited.

Examples of the present invention are shown below.
Example 1
As the burner of the present invention, an air-cooled burner shown in FIG. 1 was used. On the other hand, the water-cooled burner described in Patent Document 4 described above was used as a conventional burner.
Using the burner of the present invention and a conventional burner, silica powder having an average particle size of 20 μm is ejected into a heating furnace, and the tip of the burner is observed with a video camera from a viewing window provided in the heating furnace. The time until fusion was measured. The results are shown in Table 1 below.

The raw material powder was classified with a 200-mesh sieve until supply, and 75 μm or more was removed before use. The supply amount of the raw material powder supplied from the raw material feeder was 20 kg / h, and the raw material was supplied for 12 hours.
Oxygen was used as a carrier gas for conveying the raw material powder, and its flow rate was 7.5 Nm ³ / h.
LPG was used as the fuel gas, and the flow rate was 5 Nm ³ / h.
Oxygen was used as the combustion-supporting gas, and the flow rate was 20 Nm ³ / h.

  In addition, a bag filter was provided at the rear stage of the heating furnace to recover the flame-treated silica powder. 1 kg of the collected sample was taken and classified with a 200 mesh sieve, and the residue on the sieve was evaluated. The evaluation results are shown in Table 1 below.

As shown in Table 1, in the burner of the present invention, it was not observed that the raw material adhered to the tip of the burner during the 12 hours during which the raw material was supplied.
On the other hand, in the conventional burner, the raw material started to adhere to the tip of the burner after 2 hours from the start of the raw material supply. As the operation continued further, the adhering raw material began to melt with the heat of the burner flame. Thereafter, the melted deposits grew and a state that disturbed the combustion state of the burner flame was confirmed.

  In addition, when the sample collected by the bag filter was classified with a sieve, the particle weight of 75 μm or more not included in the raw material was 2% in the burner of the present invention, whereas the conventional burner was 15%. became. This is considered to be because in the conventional burner, the raw material adhering to the tip of the burner cooling jacket was melted and part of it was collected by the bag filter.

<Example 2>
As the burner of the present invention, an air-cooled burner shown in FIG. 1 was used. On the other hand, the water-cooled burner described in Patent Document 4 described above was used as a conventional burner.
Using the burner of the present invention and a conventional burner, silica powder having an average particle size of 20 μm was jetted into a heating furnace, and a bag filter was provided in the subsequent stage to recover the flame-treated silica powder.

Here, the burner of the present invention used oxygen as a cooling gas.
The cooling gas discharged from the cooling jacket was supplied to the raw material feeder and used as a carrier gas for the raw material powder.
The supply amount of the raw material powder supplied from the raw material feeder was 20 kg / h.
The raw material powder gas amount was 7.5 Nm ³ / h.
LPG was used as the fuel gas, and the flow rate was 5 Nm ³ / h.
Oxygen was used as the combustion-supporting gas, and the flow rate was 20 Nm ³ / h.

  The carbon concentration contained in the silica powder recovered by the bag filter was measured. The measurement results are shown in Table 2.

  As shown in Table 2, it was confirmed that the carbon concentration contained in the product was reduced in the burner of the present invention as compared with the conventional burner.

  DESCRIPTION OF SYMBOLS 1 ... Burner (powder melting burner), 1a ... Front end surface, 2 ... Raw material powder supply, 2A ... Raw material powder supply path, 2a ... Raw material injection hole, 3 ... Fuel supply pipe, 3A ... Fuel supply path, 3a ... Fuel supply hole, 4... 1st combustion-supporting gas supply pipe, 4A... 1st combustion-supporting gas supply path, 4a... 1st combustion-supporting gas supply hole, 5. 2nd combustion-supporting gas supply path, 5a ... 2nd combustion-supporting gas supply hole, 6 ... cooling jacket (cooling means), 6A ... cooling gas flow path, 6B ... temperature control unit (temperature control means), 6a ... introduction , 6b ... derivation unit, 7, 12, 14 ... flow control valve (flow control means), 8 ... thermometer (temperature measurement means), 9 ... temperature indicating controller, 10 ... raw material powder feeder, 11, 13 , 15 ... flow meter, 16 ... flow rate indicating controller, 17 ... combustion-supporting gas mixer, L1 ... cooling gas introduction path, L2 ... cooling gas lead-out Road, L3~L6 ... route

Claims (6)

A powder melting burner provided with a cooling means for cooling the burner nozzle,
A raw material powder supply path for supplying the raw material powder;
A raw material powder feeder for supplying raw material powder to the raw material powder supply path;
A raw material ejection hole provided at a tip of the raw material powder supply path;
A fuel supply path for supplying fuel;
A fuel ejection hole provided at the tip of the fuel supply path;
A combustion-supporting gas supply path for supplying oxygen or oxygen-enriched air;
A combustion-supporting gas ejection hole provided at the tip of the combustion-supporting gas supply path;
With
Said cooling means includes a cooling gas flow path having an outlet portion and inlet portion of the cooling gas, Ri cooling structure der having a temperature control means, the controlling the surface temperature of the cooling means to a required temperature,
A powder melting burner for supplying a cooling gas from the outlet to the raw material powder feeder .   The temperature control means includes temperature measurement means for measuring the temperature of the cooling gas on the derivation part side, and flow rate control means for controlling the flow rate of the cooling gas introduced into the introduction part. Powder melting burner.   The powder melting burner according to claim 1 or 2, wherein the cooling means is provided on an outermost peripheral portion of the burner nozzle.   The powder melting burner according to any one of claims 1 to 3, wherein the cooling means is provided so as to surround the burner nozzle.   The powder melting burner according to any one of claims 1 to 4, wherein the cooling gas includes a combustion-supporting gas. A combustion-supporting gas mixer that supplies the combustion-supporting gas to the combustion-supporting gas supply path;
The powder melting burner according to any one of claims 1 to 5 , wherein a cooling gas is supplied from the outlet portion to the combustion-supporting gas mixer.

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