JP5725556B2 - Glass manufacturing apparatus and glass manufacturing method - Google Patents

Description

  The present invention relates to a glass manufacturing apparatus and a glass manufacturing method that heat and melt a glass raw material in-flight to vitrify it.

  As a technology for melting glass materials, a technology that uses thermal plasma as a high-temperature heat source has been developed by applying in-flight technology instead of burning fossil fuels to heat glass materials. . Specifically, quartz glass is to be manufactured by transfer plasma melting. This is a method in which a raw material is heated and melted by a thermal plasma generated between plasma arcs formed by a pair of electrodes (anode and cathode) having opposite polarities (for example, claim 1, FIG. (See FIG. 5).

However, this method has a problem that the electrode is thermally evaporated, and the substance constituting the electrode is mixed into the fused quartz, resulting in contamination.
In order to solve this problem, it has been proposed to use inductively coupled thermal plasma by a high-frequency electric field (see, for example, claim 1 and FIG. 1 of Patent Document 2), but there are problems in terms of thermal efficiency and productivity. is there. In addition, a technique using high-frequency thermal plasma or multiphase AC arc plasma as a high-temperature heat source has been developed (see Patent Document 3).

  And in the technique of vitrifying the glass raw material by in-flight, it is shown that the high temperature of the plasma formed by the multiphase AC arc is suitable as a method for supplying sufficient energy to the glass raw material in a short time. (Refer to patent documents 3 and non-patent documents 1 to 6).

JP 2002-356337 A JP 2000-169162 A JP 2006-199549 A

Masayuki Yamane et al. “Glass Engineering Handbook”, Asakura Shoten (1999), pages 303-308 Takayuki Watanabe, Kazuyuki Yatsuda, Yao Yaochun, Tetsuji Yano, and Tsugio Matsuura: Innovative In-Flight Glass Melting Technology Using Thermal Plasmas, Pure and Applied Chemistry, accepted. Yao Yaochun, Kazuyuki Yatsuda, Takayuki Watanabe, and Tetsuji Yano: Effect of Injection Position on In-Flight Melting Behavior of Granular Alkali-Free Glass Raw Material in 12-Phase AC Arc Plasma, Plasma Science and Technology, 11 (6), p .699-703 (2009.12). Yao Yaochun, Kazuyuki Yatsuda, Takayuki Watanabe, Tsugio Matsuura, and Tetsuji Yano: Characteristics of Multi-Phase Alternating Current Arc for Glass In-Flight Melting, Plasma Chemistry and Plasma Processing, 29 (5), p.333-346 (2009.10) . Yaochun Yao, Kazuyuki Yatsuda, Takayuki Watanabe, Fuji Funabiki, and Tetsuji Yano: Investigation on In-Flight Melting Behavior of Granulated Alkali-Free Glass Raw Material in 12-Phase AC Arc, Chemical Engineering Journal, 144 (2), p.317 -323 (2008.10). Yaochun Yao, Takayuki Watanabe, Tetsuji Yano, Toru Iseda, Osamu Sakamoto, Masanori Iwamoto, and Satoru Inoue: An Innovative Energy-Saving In-Flight Glass Melting Technology and Its Application in Glass Production, Science and Technology of Advanced Materials, 9 (2 ), 025013 (2008.4-6).

  However, even if such a technique is used, a glass with a uniform vitrification state and a high vitrification rate has not been obtained. As a cause of this, in the vitrification treatment using a combustion flame such as an in-flight oxygen burner, even if the heating temperature is low and the vitrification state is uniform, a high vitrification rate cannot be obtained. Further, in the in-flight plasma vitrification treatment, a glass having a uniform vitrification state could not be obtained.

  Furthermore, even in a hybrid type vitrification process using a combustion flame and arc plasma, the uniformity of the vitrification state produced and the high vitrification rate were not sufficient. This is considered to be because the glass raw material heated by the combustion flame inhibits the arc plasma from entering the high temperature region due to the high viscosity of the arc plasma. In other words, in order to put the glass raw material into the arc plasma, a certain speed is required for the glass raw material. However, when the charging speed is high, the arc plasma becomes unstable. There was a problem of being rebounded by plasma.

  Thus, in the conventional technology, in the hybrid type glass manufacturing apparatus using the combustion flame and the arc plasma, the technology for realizing the efficient heat transfer to the glass material in the arc plasma has not been realized. is the current situation.

  Then, this invention makes it a subject to provide the hybrid type glass manufacturing apparatus and glass manufacturing method using a combustion flame and arc plasma which manufacture glass with a uniform vitrification state and high vitrification rate.

  The present invention was devised to solve the above problems, and the glass manufacturing apparatus according to claim 1 manufactures glass by heating and melting a powdery glass raw material in-flight and vitrifying it. A glass manufacturing apparatus that has a vitrification space surrounded by a heat insulating material that is a space for vitrifying the glass raw material, and is provided on the upper surface of the vitrification space and burns downward A combustion tube for generating a flame, arc plasma generating means for generating arc plasma in the vitrification space by applying multi-phase alternating currents having different phases to a plurality of columnar arc electrodes; Shield gas supply means for supplying shield gas to the tip for arc discharge, and glass for supplying the glass raw material from above the arc plasma generation region in the combustion flame And a swirl flow generating means for generating a swirl flow that descends while rotating along the inner wall of the vitrification space from above the arc plasma generation region to below the arc plasma generation region. And the plurality of arc electrodes are arranged in two upper and lower stages, each consisting of an upper electrode arranged in the upper stage and a lower electrode arranged in the lower stage, each consisting of a plurality of arc electrodes, The arc discharge tip is disposed downward, the lower electrode is disposed such that the arc discharge tip is horizontally or horizontally upward, and the polyphase alternating current applied to the arc electrode is the top view, Phase difference of alternating current applied to the arc electrodes facing each other across the center of the discharge region, which is the region surrounded by the arc discharge tip of the arc electrode The phase is determined so as not to be 180 degrees, the combustion tube is set so that the combustion flame penetrates the center of the discharge region, and the glass material supply means is arc plasma generated by the arc plasma generation means. In synchronism with the change in the spread of the high temperature region, the glass material is introduced into the combustion flame at a predetermined timing so that the glass material reaches the arc plasma generation region when the high temperature region spreads. Configured to supply.

  According to such a configuration, the glass manufacturing apparatus generates a plasma jet that flows downward by the upper electrode of the arc plasma generating means in which the tip for arc discharge is arranged downward in the glass processing space, and the tip for arc discharge. Is moderated by the lower electrode disposed upward from the horizontal to the horizontal. Here, in the glass manufacturing apparatus, a rotating magnetic field is generated by a plurality of arc electrodes to which multiphase alternating current is applied, and an induction pinch effect that contracts the arc plasma in the center direction is generated by the Lorentz force received from the rotating magnetic field.

  In addition, the glass manufacturing apparatus supplies shield gas to the tip of the arc electrode by the shield gas supply means, and prevents the tip from being oxidized by placing the tip in a shield gas atmosphere. Since the outer side of the arc plasma is cooled by surrounding it with a shielding gas, a thermal pinch effect is generated that contracts the arc plasma in the center direction.

  Moreover, a glass manufacturing apparatus generate | occur | produces the combustion flame which penetrates the center part of arc plasma with a combustion tube. Here, in the glass manufacturing apparatus, the phase difference of the alternating current applied to the arc electrodes facing each other across the center of the discharge region, which is the region surrounded by the tip of the arc electrode, is 180 degrees as viewed from above by the arc plasma generating means. That is, a multiphase alternating current is applied to each arc electrode so as not to have a maximum phase difference. For this reason, although the combustion flame penetrates the central portion of the discharge region, the arc discharge passing through the central portion is reduced, so that the arc plasma is stably formed.

  Further, the glass manufacturing apparatus generates a swirling flow that descends while rotating along the inner wall of the glass processing space by the swirling flow generating means, so that the arc plasma is generated and the inner wall of the glass processing space that is the outer periphery thereof. A pressure difference is created between the vicinity and the result is a swirling effect that contracts the arc plasma toward the center.

  Moreover, a glass manufacturing apparatus supplies a powdery glass raw material in a combustion flame by a glass raw material supply means. At this time, the glass material enters the arc plasma while being uniformly heated by the combustion flame. Then, the glass material descends on the plasma jet of arc plasma. In this way, the glass manufacturing apparatus heats and melts the glass raw material that has been heated uniformly by the combustion flame to a higher temperature in the arc plasma to be vitrified.

  Here, arc plasma is subjected to contraction force due to induction pinch effect, thermal pinch effect and swirl effect, and does not become unstable due to the combustion flame. Without being heated by the arc plasma.

Further, the glass manufacturing apparatus intermittently supplies the glass raw material by the glass raw material supply means so that the glass raw material reaches the arc plasma when the high temperature region spreads in synchronization with the change of the high temperature region of the arc plasma. Supply.
As a result, the glass manufacturing apparatus is capable of effectively producing glass by arc plasma that forms a plasma jet that does not diverge, stabilizes, and moderately relaxes the flow rate of glass raw material that has been heated and heated uniformly by a combustion flame. The raw material is heated and melted.

  A glass manufacturing apparatus according to a second aspect is the glass manufacturing apparatus according to the first aspect, wherein the combustion tube is an oxygen burner.

  According to such a configuration, the glass manufacturing apparatus generates a combustion flame having a temperature higher than that of a normal burner by the oxygen burner, and the glass raw material is heated to a higher temperature by this combustion flame and enters the arc plasma. Heat to melt and vitrify.

  The glass manufacturing apparatus according to claim 3 is the glass manufacturing apparatus according to claim 1 or 2, wherein the upper electrode has a tip at which the arc discharge with respect to the horizontal is 15 degrees or more and 45 degrees or less. The lower electrode was configured such that the arc discharge tip was installed upward at an angle of 0 ° to 10 ° with respect to the horizontal.

  According to such a configuration, the glass manufacturing apparatus heats the glass raw material by arc plasma that forms a plasma jet whose flow velocity is suitably relaxed by the arc plasma generating means, using the upper electrode and the lower electrode.

  The glass manufacturing apparatus according to claim 4 is the glass manufacturing apparatus according to any one of claims 1 to 3, wherein each of the upper electrode and the lower electrode has an arc discharge tip. The concentric circles are arranged radially so as to be located on concentric circles having a predetermined diameter in the glass processing space, and the diameter of the concentric circle where the arc discharge tip of the upper electrode is located is located at the tip of the lower electrode arcing. It was configured to be smaller than the diameter of the concentric circles.

  According to such a configuration, the glass manufacturing apparatus uses the upper electrode arranged so that the diameter of the circle where the tip is located is reduced by the arc plasma generating means, and the glass raw material heated by the combustion flame is rapidly changed. The glass raw material is not diffused by heating and generating a plasma jet at a high flow rate. In addition, the glass manufacturing apparatus uses an arc plasma generator to reduce the flow velocity of the plasma jet generated by the upper electrode by using the lower electrode arranged so that the diameter of the circle where the tip is located is relatively large. The residence time of the glass raw material in the arc plasma is lengthened. Thereby, a glass manufacturing apparatus heats a glass raw material for a long time with arc plasma.

  The glass manufacturing apparatus according to claim 5 is the glass manufacturing apparatus according to any one of claims 1 to 4, wherein the upper electrode and the lower electrode each have six arc electrodes, When viewed from above, the upper electrodes and the lower electrodes that are adjacent to each other are arranged at an angle of 60 degrees when viewed from above, and are disposed at an angle of 30 degrees when viewed from above, and the polyphase alternating current is 12 The twelve arc electrodes that are phase alternating current and arranged at an angle of 30 degrees in the top view, and the phase of the alternating current applied to one arc electrode and the second arc electrode and the second in the top view The 12-phase alternating current is applied to the arc electrode so that the difference from the alternating current phase applied to any one of the fourth adjacent arc electrodes is 180 degrees.

  According to such a configuration, the glass manufacturing apparatus generates the arc plasma by the arc plasma generating means while reducing the arc discharge passing through the central portion of the discharge region through which the combustion flame penetrates. Thereby, a glass manufacturing apparatus heats a glass raw material with the arc plasma formed stably.

  The glass manufacturing apparatus according to claim 6 is the glass manufacturing apparatus according to any one of claims 1 to 5, wherein the rotation direction of the arc plasma and the rotation direction of the combustion flame in a plan view are The rotational direction of the swirl flow is the same direction.

  According to such a configuration, the glass manufacturing apparatus aligns the rotational direction of the rotational flow of each part, so that the air current is not disturbed and arc plasma is not diffused. As a result, the glass manufacturing apparatus heats the glass material descending on the plasma jet without causing it to diverge.

  The glass production method according to claim 7, wherein the glass production method comprises producing glass by heating and melting a powdery glass raw material by in-flight and vitrifying it. A glass manufacturing method using an apparatus, the step of supplying a glass raw material into a combustion flame, the step of heating the glass raw material by a combustion flame, and the step of heating the glass raw material heated by the combustion flame by arc plasma, , Including.

  According to this procedure, in the step of supplying the glass raw material, the glass manufacturing apparatus supplies the glass raw material into the combustion flame by the glass raw material supply means. Next, in the step of heating the glass material with a combustion flame, the glass manufacturing apparatus uniformly heats and raises the temperature of the glass material with the combustion flame generated by the combustion tube. And in the process of heating a glass raw material by arc plasma, a glass manufacturing apparatus heat-melts the glass raw material heated and heated uniformly by the combustion flame to high temperature by arc plasma, and vitrifies it.

  At this time, the arc plasma does not diverge due to each pinch effect, and is formed so as to generate a plasma jet with an appropriate flow rate without becoming unstable due to the combustion flame penetrating the center portion. Then, the glass manufacturing apparatus burns the glass raw material by the glass raw material supply means so that the glass raw material reaches the arc plasma when the high temperature region spreads in synchronization with the change of the high temperature region of the arc plasma. It is vitrified efficiently by supplying it into the flame.

According to the first aspect of the present invention, the glass material heated uniformly by the combustion flame does not diverge, is stabilized, the flow rate is relaxed, and is efficiently heated by the arc plasma in which the high temperature region is widened. Therefore, glass with a uniform vitrification state and a high vitrification rate can be produced.
Since the invention according to claim 2 uses an oxygen burner that generates a high-temperature combustion flame, a glass with a more uniform vitrification state and a high vitrification rate can be produced.
According to invention of Claim 3, since a glass raw material is heated with the plasma jet by which the flow rate was moderated suitably, glass with a uniform vitrification state and a high vitrification rate can be manufactured.
According to the invention described in claim 4, since the glass raw material is rapidly heated by the arc plasma and is heated for a long time, a glass having a high vitrification rate can be produced.
According to the fifth aspect of the present invention, since the arc plasma through which the combustion flame penetrates reduces the arc discharge passing through the center of the generation region, the arc plasma can be generated stably. As a result, glass with a uniform vitrification state can be produced.
According to the invention described in claim 6, since the arc plasma is not diffused, and therefore, the glass raw material descending on the plasma jet can be heated to a high temperature without diverging. Glass can be produced with a uniform and high vitrification rate.
According to the invention described in claim 7, it is possible to produce the glass by enjoying the effects of the invention described in claims 1 to 6.

It is a typical fragmentary sectional view seen from the front which shows the composition of the glass manufacture device concerning the embodiment of the present invention. It is a typical top view which shows the structure of the arc electrode in the glass manufacturing apparatus which concerns on embodiment of this invention. It is a typical top view which shows the structure of the gas supply pipe for the swirl | flow generation in the glass manufacturing apparatus which concerns on embodiment of this invention. It is a figure explaining the phase of the alternating voltage applied to the arc electrode in the glass manufacturing apparatus which concerns on embodiment of this invention. It is a typical top view which shows the example of the electrode arrangement | positioning of the arc electrode in the glass manufacturing apparatus which concerns on embodiment of this invention. It is a flowchart which shows the flow of a process of the glass manufacturing apparatus which concerns on embodiment of this invention. It is the typical fragmentary sectional view seen from the front which shows the structure of the glass manufacturing apparatus which concerns on the Example of this invention. It is a time chart which shows an example of the operating condition of the glass manufacturing apparatus which concerns on the Example of this invention.

Embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
[Configuration of glass manufacturing equipment]
First, with reference to FIGS. 1-3, the structure of the glass manufacturing apparatus which concerns on embodiment of this invention is demonstrated.
The glass manufacturing apparatus 1 according to the embodiment of the present invention shown in FIG. 1 heats and melts the powdery glass raw material 4 in-flight (in the air) by virtue of the arc plasma 2 and the combustion flame 3. Is a device for producing glass.

  The glass manufacturing apparatus 1 includes a furnace 10, an arc plasma generation unit 20, a combustion tube 30, a swirl flow generation unit 40, and a glass raw material supply unit 50.

  The furnace 10 has a cylindrical shape and includes a heat insulating material 11, a cooling jacket 12, and a collection pot 13. Further, an exhaust port 10 a communicating with the vitrification space 11 a is provided at the lower side of the furnace 10. The exhaust port 10a is connected to an exhaust gas processing device (not shown), and appropriately processes exhaust gas generated by vitrification processing.

  The heat insulating material 11 constitutes the main body of the furnace 10, and a columnar vitrification space 11a surrounded by an inner wall 11b is formed at the center. The vitrification space 11a is a space for vitrifying the glass raw material 4 in-flight. Further, the heat insulating material 11 is provided with through holes at various places, and an upper arc electrode 21, a lower arc electrode 22, a combustion pipe 30, and a gas supply pipe 42 are disposed. Since the inside of the furnace 10 is heated to a high temperature by the arc plasma 2 and the combustion flame 3, for example, refractory bricks can be used as the heat insulating material 11.

  The cooling jacket 12 is a cooling device that covers the outer periphery (side surface and upper surface) of the heat insulating material 11 and does not radiate heat to the outside. The cooling jacket 12 in the present embodiment cools the entire jacket by supplying cooling water from a cooling water supply port 12a provided in the lower portion, and then discharges cooling water from a cooling water discharge port 12b provided in the upper portion. It is a metal water-cooling type cooling device configured to do this.

  Further, at various locations of the cooling jacket 12, through-holes communicating with the above-described through-holes provided at various locations of the heat insulating material 11 are provided, and the upper arc electrode 21, the lower arc electrode 22, the combustion tube 30, and the gas A supply pipe 42 is provided.

  The collection pot 13 is a container that is provided in the lower portion of the furnace 10 and collects glass particles that fall when the glass raw material 4 is vitrified in the vitrification space 11a. In order to collect high-temperature glass particles, for example, an iron or stainless steel container can be used as the collection pot 13.

The arc plasma generation means 20 includes an upper arc electrode 21, a lower arc electrode 22, a multiphase AC power supply 23, and a shield gas supply means 24.
The arc plasma generating means 20 applies alternating currents of different phases to the upper arc electrode 21 and the lower arc electrode 22 (hereinafter, appropriately referred to as arc electrodes 21 and 22) from the multiphase AC power source 23, respectively, to the tip 21a and Arc discharge is performed between the tip portions 22a, and arc plasma 2 is generated in a region surrounded by the tips of the tip portions 21a and 22a of the arc electrodes 21 and 222.

The arc plasma generating means 20 in the present embodiment has six columnar upper arc electrodes 21 and six columnar lower arc electrodes 22, and each has a top view as shown in FIG. They are arranged radially around the center of the vitrification space 11a at an angle of 60 degrees. Further, the upper arc electrode 21 and the lower arc electrode 22 are arranged 30 degrees apart from each other when viewed from above. Therefore, a total of 12 arc electrodes 21 and 22 are arranged at equal intervals with an angle of 30 degrees as viewed from above. And the front-end | tip part 21a of the upper side arc electrode 21 and the front-end | tip part of the front-end | tip part 22a of the lower side arc electrode 22 are each arrange | positioned so that it may be located on the concentric circle of the vitrification space 11a in top view. Hereinafter, the concentric circles will be appropriately referred to as an upper electrode tip circle 21b and a lower electrode tip circle 22b, respectively. In the example shown in FIG. 2, the diameter of the upper electrode tip circle 21 b that is a concentric circle for the upper arc electrode is smaller than the diameter of the lower electrode tip circle 22 b that is a concentric circle for the lower arc electrode 22. .
The diameter of the upper electrode tip circle 21b and the diameter of the lower electrode tip circle 22b may be set to be the same.

Further, as shown in FIG. 1, the arc electrodes 21 and 22 are disposed in the through holes of the heat insulating material 11 and the cooling jacket 12 provided on the side surface of the furnace 10.
Here, the upper arc electrode 21 is disposed obliquely downward, and the lower arc electrode 22 is disposed slightly obliquely upward with respect to horizontal or horizontal.

  The arrangement angle of the upper arc electrode 21 is preferably set to 15 degrees or more and 45 degrees or less downward with respect to the horizontal, and more preferably about 30 degrees. As a result, a downward plasma jet can be generated.

  Further, it is preferable that the arrangement angle of the lower arc electrode 22 is slightly upward with respect to horizontal or horizontal. Specifically, it is preferably 0 degree or more and 10 degrees or less upward with respect to the horizontal, and more preferably about 5 degrees. As a result, the flow velocity of the plasma arc generated by the upper arc electrode 21 toward the lower side can be relaxed, and the residence time of the glass raw material 4 in the arc plasma 2 can be lengthened. For this reason, the glass raw material 4 can be heated by the arc plasma 2 for a long time, and a vitrification process with a uniform and low vitrification rate in a vitrified state can be performed.

  Each of the arc electrodes 21 and 22 is configured to be freely movable in the axial direction by a motor drive (not shown), and the tip of the upper electrode that is a circle with which the tip of the tip portion 21a of the upper arc electrode 21 contacts. The diameter of the circle 21b and the diameter of the lower electrode tip circle 22b, which is a circle in contact with the tip of the tip portion 22a of the lower arc electrode 22, can be adjusted.

  Therefore, in this embodiment, the arc electrodes 21 and 22 are arranged so that the diameter of the upper electrode tip circle 21b is smaller than the diameter of the lower electrode tip circle 22b. As a result, the upper electrode tip circle 21b whose diameter is adjusted to be small is arranged such that the tip portions 21a are close to each other, and the glass raw material 4 heated by the combustion flame 3 is rapidly heated and melted. In addition, since the glass raw material 4 is placed on a plasma jet having a high flow velocity, the glass raw material 4 can be heated while being prevented from divergence.

  Further, the lower arc electrode 22 in which the diameter of the lower electrode tip circle 22b is adjusted to be relatively large, the tip portions 22a are slightly separated from each other, and the flow velocity of the plasma jet formed by the upper arc electrode 21 is reduced. The residence time of the glass raw material 4 in the high-temperature arc plasma 2 can be increased. Thereby, the vitrification rate can be improved.

  The diameters of the upper electrode tip circle 21b and the lower electrode tip circle 22b can be set within a range where stable arc discharge is possible, and can be separated, for example, to a diameter of about 100 [mm]. Further, the distance in the height direction between the tip of the tip portion 21a of the upper arc electrode 21 and the tip of the tip portion 22a of the lower arc electrode 22 can be increased to about 20 [mm]. Thereby, the arc plasma 2 having a sufficient volume for vitrification can be formed.

  As described above, when the arc electrodes 21 and 22 are arranged so that the diameter of the upper electrode tip circle 21b is smaller than the diameter of the lower electrode tip circle 22b, for example, the lower electrode tip circle 22b Is 100 [mm], the upper electrode tip circle 21b preferably has a diameter of about 70 to 90 [mm].

  Further, the tip portion 21a of the upper arc electrode 21 and the tip portion 22a of the lower arc electrode 22 are both provided below the combustion tube 30, and the combustion flame 3 generated by the combustion tube 30 and extending downward is discharged. The upper electrode tip circle 21b and the lower electrode tip circle 22b, which are regions, are arranged so as to pass through. Thereby, a region where the heating region by the arc plasma 2 and the heating region by the combustion flame 3 overlap is formed, and the glass raw material falling from the center of the combustion tube 30 can be efficiently heated to a high temperature.

  Since the tip portions 21a and 22a of the arc electrodes 21 and 22 are heated to high temperatures by arc discharge, it is preferable to use tungsten having a high melting point, a tungsten alloy, hafnium, or the like.

  Further, the arc electrodes 21 and 22 have a multi-tube structure, and are configured such that the shield gas is supplied by the shield gas supply means 24 through the inner layer, and the tip portions 21a and 22a have an atmosphere of the shield gas. Has been. As a result, it is possible to prevent oxidation of the tip portions 21a and 22a that become high temperature due to arc discharge and to cool the tip portions 21a and 22a.

  Further, cooling water is flown through the two outer layers of the multi-tube structure of the arc electrodes 21 and 22, so that the arc electrodes 21 and 22 are prevented from being overheated.

The multi-phase AC power supply 23 supplies electric power for applying an arc discharge between the arc electrodes by applying to the arc electrodes 21 and 22 a multi-phase AC having a predetermined phase difference for each electrode. In the present embodiment, the multiphase AC power supply 23 supplies 12-phase AC as multiphase AC.
In addition, the pattern which applies a polyphase alternating current with respect to each arc electrode 21 and 22 is mentioned later.

The number of phases of the polyphase alternating current is not limited to 12 phases, but is preferably 3 or more. As a result, the plasma arc 2 having a large volume can be generated.
In addition, it is preferable that the number of phases is a multiple of three because a multiphase alternating current can be generated relatively easily using a commercial three-phase alternating current. As such a multiphase AC power supply, for example, a known power supply device (see Japanese Patent No. 3094217) that converts commercial 3-phase AC to 12-phase AC that is shifted in phase by 30 degrees can be used.

The shield gas supply means 24 supplies shield gas to the tip portions 21a and 22a through the tubes of the tubular arc electrodes 21 and 22. As the shielding gas, for example, a rare gas such as argon gas, or a mixed gas obtained by adding about 10 mol% of hydrogen gas to argon gas can be used.
The shield gas supply means 24 is preferably provided with a pressure regulator in order to supply shield gas at an appropriate flow rate.

  Here, the shielding gas is used for the purpose of preventing oxidation of the tip portions 21a and 22a of the arc electrodes 21 and 22, but the shielding gas is used for the electric conductivity and the thermal conductivity of the arc plasma 2. It has a big influence. That is, by controlling the supply amount of the shielding gas, the electric conductivity can be adjusted to control the magnitude of the annular current flowing in the arc plasma 2, and the thermal conductivity can be adjusted from the arc plasma 2. The amount of heat transfer to the glass raw material 4 can be controlled.

Further, by cooling the outside of the arc plasma 2 with the shielding gas, a thermal pinch effect is generated to prevent the arc plasma 2 from divergence, and the glass material 4 is confined together with the arc plasma 2 in the central portion of the vitrification space 11a. be able to.
The thermal pinch effect refers to an effect of contraction to reduce the surface area in order to prevent the loss of thermal energy from increasing when the plasma is cooled.

  The combustion tube 30 is disposed in a through-hole of the heat insulating material 11 and the cooling jacket 12 provided in the center of the upper surface of the furnace 10, and generates a combustion flame 3 extending downward, It has the function of a glass raw material supply pipe that is introduced into the center of the combustion flame 3 using carrier gas.

In the present embodiment, an oxygen burner is used as the combustion tube 30. The combustion pipe 30 has a six-pipe structure, and the combustion pipe 30 has a glass raw material supply port 30a, a fuel gas supply port 30b, a primary oxygen supply port 30c, a second pipe communicating with each layer of the six-pipe structure. A secondary oxygen supply port 30d, a cooling water supply port 30e, and a cooling water discharge port 30f are provided. The hexagonal pipe is used in order from the inside for glass raw material input, fuel gas supply, primary oxygen supply, secondary oxygen supply, cooling water supply and cooling water discharge.
In addition, propane gas, hydrogen gas, etc. can be used as fuel gas.

Here, the contribution of the combustion flame 3 to vitrification will be briefly described.
In the in-vitro vitrification process using the combustion flame 3, the powdery glass raw material 4 particles are supplied from the outlet of the combustion flame 3 to the center of the combustion flame 3. At this time, compared with the heating by the arc plasma 2, although it is not necessarily sufficient for the temperature required for vitrification, it can be heated in a long time when the particles of the glass raw material 4 fall in the vertically long combustion flame 3, It is possible to uniformly raise the temperature of all the particles of the glass raw material 4 to be charged.

  In addition, by using an oxygen burner as the combustion tube 30 as in the present embodiment, the combustion flame 3 having a temperature higher than that of a normal burner can be generated. Therefore, the glass raw material 4 can be heated to a temperature higher than that of a normal burner, which is preferable for improving the vitrification rate.

  In the hybrid heating system combined with the arc plasma 2, the glass raw material 4 heated uniformly by the combustion flame 3 is heated and melted by the high-temperature arc plasma 2 and is vitrified without unevenness.

Here, the combustion flame 3 generated by the combustion tube 30 rotates about the extending direction as a central axis. The rotation direction, the rotation direction of the arc plasma 2, and the swirling flow generated by the swirling flow generating means 40. It is preferable to match the rotation direction.
Note that the rotation direction of the combustion flame 3 is determined according to the ejection direction of the fuel gas or oxygen gas, or the fuel gas and oxygen gas determined by the shape of the nozzle of the combustion tube 30.

  The swirl flow generating means 40 generates a swirl flow that is a spiral air flow descending downward from the upper part of the vitrification space 11a while rotating along the inner wall 11b of the heat insulating material 11 that is the inner wall of the furnace 10. It is something to be made. The swirling flow generating means 40 includes a gas supply source 41 and a gas supply pipe 42.

  By this swirling flow, a pressure difference can be generated between the inner wall 11b side of the vitrification space 11a and the central portion. At this time, since the pressure on the inner wall 11b side becomes high, the arc plasma 2 generated inside the swirling flow can be contracted so as to be confined in the central portion, and can be prevented from divergence. The glass material 4 can be efficiently heated to a high temperature by the arc plasma 2 contracted by the swirl effect.

  The gas supply source 41 supplies a gas for generating a swirling flow, and as such a gas, for example, nitrogen gas or air can be used. Moreover, it is preferable that the gas supply source 41 includes a pressure regulator in order to supply gas at an appropriate flow rate.

The gas supply pipe 42 is disposed in a through hole that penetrates the heat insulating material 11 and the cooling jacket 12 provided on the side surface of the furnace 10.
In the present embodiment, as shown in FIG. 3, the gas outlets of the four gas supply pipes 42 are equally spaced on the circumference of the inner wall 11b of the circular vitrification space 11a in a top view. Has been placed. Further, the gas supply pipes 42 are arranged such that airflows ejected from the outlets of the gas supply pipes 42 in the tangential direction of the inner wall 11b are in the same rotational direction along the inner wall 11b of the vitrification space 11a. ing. Note that this rotation direction is preferably the same as the rotation direction of the arc plasma 2 and the combustion flame 3. As a result, a stable rotating flow can be formed without being disturbed by each other, and the arc plasma 2 and the combustion flame 3 do not diverge. For this reason, the glass raw material 4 which descends on the plasma jet which is the rotational flow of the arc plasma 2 is efficiently heated without being diverged.

  Further, as shown in FIG. 1, the gas supply pipe 42 is disposed so as to have an angle from the horizontal to the downward in a front view. This arrangement angle is preferably 15 degrees or more and 45 degrees or less, and more preferably about 30 degrees. As a result, the gas ejected from the gas supply pipe 42 forms a downdraft that spirals.

  Moreover, in this embodiment, although the jet outlet of the gas supply pipe 42 is provided in the upper part of the vitrification processing space 11a, it is preferable to provide it at least above the upper end of the region where the arc plasma 2 is generated. Further, it is preferable that a swirl flow is formed at least below the lower end of the region where the arc plasma 2 is generated. Thereby, a swirl flow surrounding the generation region of the arc plasma 2 can be generated.

  In the present embodiment, the number of the gas supply pipes 42 is four. However, the number of the gas supply pipes 42 is not limited to this, and may be one to several. Moreover, the shape of a jet nozzle is not limited to a circle, It is good also as a polygon, an ellipse, a rectangle, etc.

  The glass raw material supply means 50 supplies the powdery glass raw material 4 to the glass raw material supply port 30a of the combustion tube 30 using carrier gas. The glass raw material supply means 50 in this embodiment is comprised from the carrier gas supply source 51, the glass raw material supply device 52, and the raw material supply amount control means 53, as shown in FIG.

  The carrier gas supply source 51 supplies a carrier gas for conveying the powdery glass raw material 4 to the glass raw material supply device 52, and a pressure cylinder or a pump can be used. As the carrier gas, air, nitrogen gas, rare gas, or the like can be used. The carrier gas supply means 51 may include a pressure regulator so as to adjust the pressure of the supplied carrier gas.

  The glass raw material supply unit 52 accumulates the powdery glass raw material 4, and the accumulated glass raw material is supplied as a powder flow through the raw material supply amount control means 53 by the carrier gas supplied from the carrier gas supply source 51. This is supplied to the glass raw material supply port 30 a of the combustion tube 30.

  The raw material supply amount control means 53 is composed of a pressure regulator, a valve, and the like, and is introduced into the glass raw material supply port 30a by controlling the carrier gas flowing out from the glass raw material supply device 52, that is, the flow rate of the powder flow. The amount of the glass raw material 4 is controlled.

Here, when the glass raw material 4 is supplied, the carrier gas supply source 51 and the gas source 4 so that the speed of the glass raw material 4 entering the arc plasma 2 is 5 [m / sec] or more and 10 [m / sec] or less. It is preferable to set the pressure and flow rate of the carrier gas by the raw material supply control means 53.
By making it 5 [m / sec] or more, it becomes easy for the arc plasma 2 having a high viscosity to enter the high temperature region, and by making it 10 [m / sec] or less, the arc plasma 2 is introduced by the entrance of the glass raw material 4. 2 can be prevented from becoming unstable.

  The glass raw material 4 is not particularly limited. For example, fine powder raw materials such as silica sand, sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate, quicklime, aluminum oxide, sodium sulfate, borax, and feldspar, and A mixed glass raw material containing glass cullet or the like is used after being formed into particles. As a method for preparing a mixed glass raw material by forming into a particulate form, a method such as spray drying or pellet processing can be used.

  The particle size of the mixed glass raw material used as the glass raw material 4 in the present embodiment may be as small as possible with a particle size of 1 mm or less because it can be heated in a short time and the generated gas can be easily diffused. Preferably, those having a particle size of 0.1 mm or more are preferable from the viewpoint of cost increase due to pulverization of raw materials and reduction in composition variation between particles.

Here, a change in the temperature distribution of the arc plasma 2 will be described.
The arc plasma 2 generated by using multi-phase alternating current (12-phase alternating current in this embodiment) has a temperature distribution inside the arc plasma 2 as the arc discharge moves through the 12 arc electrodes 21 and 22, That is, the spread of the high temperature region changes with time. The time constant of the change in the temperature distribution of the arc plasma 2 is on the order comparable to the time during which the glass raw material 4 stays inside the arc plasma 2.
For example, when a 12-phase AC power supply of 50 Hz is used, the change in temperature distribution is about 20 [ms]. Moreover, the time for the glass raw material 4 to stay in the arc plasma 2 having a height of several tens [mm] is several tens [ms].

  Therefore, among the particles of the glass raw material 4 that pass through the arc plasma 2, there are particles that are sufficiently exposed to the high temperature of the arc plasma 2 and particles that pass through a relatively low temperature portion of the arc plasma 2. However, it is considered that it affects the uniformity of the vitrification state and the vitrification rate.

  Therefore, in the present embodiment, the raw material supply amount control means 53 synchronizes with the change in the temperature distribution of the arc plasma 2 generated by the arc plasma generation means 20, and the glass raw material 4 is supplied to the arc plasma 2 at a wide timing in the high temperature region. The flow rate of the carrier gas is intermittently controlled so as to reach.

  The raw material supply amount control means 53 controls the flow rate by performing opening / closing control of a valve (not shown) in synchronization with a change in the temperature distribution of the arc plasma 2. Note that the period (frequency) of change in the temperature distribution of the arc plasma 2 is the number of phases of the multiphase alternating current used in the arc plasma generating means 20, the frequency of the alternating current, each phase of the multiphase alternating current, and the arc electrodes 21, 22. And an electrode arrangement pattern that defines the correspondence between the two. For example, when arc discharge occurs mainly between adjacent arc electrodes, the high temperature region is narrowed, and when arc discharge occurs mainly between the arc electrodes facing each other across the center, the high temperature region is widened. Therefore, the temperature distribution changes periodically depending on the configuration such as the AC frequency described above.

  Therefore, the raw material supply amount control means 53 can input multiphase alternating current from the multiphase alternating current power supply 23 via a signal line (not shown) and use it as a synchronization signal.

  In addition, the phase condition in the flow rate control for allowing the glass raw material 4 to reach the arc plasma 2 at the timing when the high temperature region is maximized in the temperature distribution of the arc plasma 2 within one cycle of the temperature distribution change is previously tested. The timing is controlled in advance.

  Note that the temperature distribution of the arc plasma 2 is, for example, 50 [Hz] when the arc electrodes 21 and 22 are driven by 12-phase alternating current with each phase being 50 Hz, and finely 50 [Hz] × 12 = It changes periodically at 600 [Hz]. For this reason, in this embodiment, the raw material supply amount control means 53 changes the flow rate of the carrier gas so as to synchronize with the change of 50 [Hz] which is the frequency of the large change.

  Further, the flow rate control of the carrier gas by the raw material supply amount control means 53 may be made to switch the flow rate on and off in a rectangular pulse within one cycle of temperature change, or smoothly in a sinusoidal flow rate. May be changed.

  In the present embodiment, the raw material supply amount control means 53 is disposed between the glass raw material supply device 52 and the glass raw material supply port 30a of the combustion tube 30, but the present invention is not limited to this. For example, the raw material supply amount control means 53 may be disposed between the carrier gas supply source 51 and the glass raw material supply device 52, or a pressure regulator, a valve, or the like is provided upstream and downstream of the glass raw material supply device 52. These components may be provided separately.

[Electrode arrangement]
Next, referring to FIGS. 4 and 5 (refer to FIGS. 1 and 2 as appropriate), the electrode arrangement pattern of the multiphase alternating current applied to the arc electrodes 21 and 22 in the arc plasma generating means 20 according to the present embodiment will be described. To do.

  FIG. 4 shows the phase difference of the alternating voltage applied to each of the twelve arc electrodes 21 and 22. In FIG. 4, the numerical values shown in 12 places of the AC voltage waveform for one cycle indicate the electrode numbers assigned to the arc electrodes 21 and 22. Here, the 12-phase AC voltage is shifted by 30 degrees (1/12 period), and is set so that the phases are sequentially delayed by 30 degrees from electrode numbers 1 to 12. Accordingly, the AC voltage applied to the first electrode and the seventh electrode is 180 degrees out of phase, and the voltage difference between the first electrode and the seventh electrode is maximized when viewed from the first electrode. That is, it means that arc discharge occurs most strongly between electrodes whose phases are shifted by 180 degrees.

FIG. 5 shows the twelve arc electrodes 21 and 22 in a top view, and shows a state in which electrode numbers are assigned to the arc electrodes 21 and 22, that is, electrode arrangement.
In the example shown in FIG. 5, the applied AC voltage is 180 degrees out of phase (that is, the phase difference is maximized) (for example, No. 1 and No. 7, No. 3 and No. 9, No. 5 and No. 11). , Etc.) are positioned so as to be separated from each other by two adjacent electrodes (the positional relationship in the top view regardless of whether the upper arc electrode 21 or the lower arc electrode 22 is located), that is, the third adjacent to each other. The arc electrodes 21 and 22 are arranged.

The order of discharge is as follows. First, if an electrode discharges first, then the opposite electrode discharges second, and the electrode next to the first electrode discharges third. This is an electrode arrangement (this electrode arrangement is referred to as electrode arrangement D).
This electrode arrangement D makes it possible to continuously maintain a stable arc discharge even in combination with the combustion flame 3 and the arc plasma 2 formed by the multiphase AC arc.

Here, in the hybrid heating system using the combustion flame 3 and the arc plasma 2 by the multiphase AC arc discharge, the electrode arrangement of the arc electrodes 21 and 22 and the stability of the arc plasma 2 generated by the arc discharge explain.
In the hybrid heating system as in this embodiment, the combustion flame 3 is blown to the centers of the upper electrode tip circle 21b and the lower electrode tip circle 22b, which are discharge regions, and face each other across the center of the discharge region. The arc plasma 2 generated by the arc discharge between the electrodes becomes unstable.

  The electrode arrangement is such that the phase difference between the electrodes facing each other across the center of the upper electrode tip circle 21b and the lower electrode tip circle 22b is always the maximum, that is, the maximum voltage, and the order of discharge is determined by the arc electrodes 21 and 22. When the electrode arrangement is such that it rotates clockwise or counterclockwise (this electrode arrangement is referred to as electrode arrangement A), the arc discharge is always directed toward the center of the upper electrode tip circle 21b and the lower electrode tip circle 22b. Therefore, the arc plasma 2 is always in the center between the opposed electrodes.

  In the case of the electrode arrangement A, considering the combination with the combustion flame 3, the flame of the combustion flame 3 is always sprayed to the center position between the opposed electrodes where the arc plasma 2 exists. Although the combustion flame 3 is considerably lower in temperature than the arc plasma 2, it is considered that the arc discharge becomes unstable when the gas of the combustion flame 3 is blown onto the arc plasma 2. Further, in the vitrification process, in addition to the arc plasma 2 being in such an unstable state, the particles of the glass raw material 4 are also sent together with a low-temperature carrier gas. Stability will be further increased.

  Therefore, in the present embodiment, in order to continuously maintain a stable arc discharge, the electrode arrangement generates the arc plasma 2 and the upper electrode tip circle 21b and the lower electrode tip circle 22b to which the combustion flame 3 is sprayed are arranged. It is intended to be removed from the center. Thereby, the stable arc plasma 2 can be continuously maintained.

  Such an electrode arrangement is not limited to the electrode arrangement D described above, and the arrangement of the electrodes having the maximum phase difference is set to a position other than the opposing positions in the circle formed by the tips of the arc electrodes 21 and 22. This can be achieved. However, when the electrode arrangement with the maximum phase difference is an adjacent electrode, the high-temperature region generated by the arc plasma 2 is narrowed, and therefore, it is preferable to set an appropriate interval. For example, in the case of a 12-phase AC arc as in the present embodiment, the phase difference is present in the electrodes (that is, the second to fourth adjacent electrodes) separating the adjacent one to three arc electrodes 21 and 22. It is preferable to arrange the electrodes so that the maximum AC voltage is applied.

Here, the property of the arc plasma 2 generated using multiphase alternating current will be described.
The twelve arc electrodes 21 and 22 are applied with AC voltages having different phases from each other by the multiphase AC power source 23, and a rotating magnetic field is generated by the current flowing through the arc electrodes 21 and 22. The rotating direction of the rotating magnetic field can be changed by the electrode arrangement which is a method of connecting the arc electrodes 21 and 22 and the multiphase AC power source 23. When the electrode arrangement is the electrode arrangement D described above, the rotation direction of the rotating magnetic field is a right rotation in a top view.

  Further, since the arc plasma 2 has conductivity, an annular current (eddy current) is generated in the arc plasma 2 by this rotating magnetic field. The annular current is generated at the tips of the tip portions 21a and 22a of the arc electrodes 21 and 22 to which a voltage is applied, and at the tips of the tip portions 21a and 22a of the arc electrodes 21 and 22 facing each other across the center, The direction of rotation is reversed. Further, these annular currents rotate together with the rotating magnetic field, and the arc plasma 2 has a large spiral motion that rotates rightward when viewed from above. For this reason, the arc plasma 2 receives the Lorentz force from the rotating magnetic field and contracts in the center direction by the induction pinch effect which is a kind of magnetic pinch effect. Furthermore, this rotating magnetic field adds kinetic energy to the electrons and charged particles in the arc plasma 2 that receives the Lorentz force, and heats the glass material 4 to a higher temperature.

  Further, since the upper arc electrode 21 is disposed at an angle downward with respect to the horizontal, the arc plasma 2 itself is a plasma jet that is pushed downward. Therefore, the arc plasma 2 forms a plasma jet that descends while rotating clockwise in a top view.

  Then, when the glass raw material 4 heated by the combustion flame 3 is introduced from above into the central portion of the arc plasma 2 that is a plasma jet, the glass raw material 4 is heated by the high-temperature arc plasma 2 while being swirled by the plasma jet. Move downward along At this time, it is preferable that the rotation direction of the gas of the combustion flame 3 at the outlet of the combustion tube 30 also coincides with the rotation direction of the arc plasma 2.

  Thereby, since the arc plasma 2 and the combustion flame 3 are not disturbed in rotation, the arc plasma 2 and the combustion flame 3 do not diverge and can maintain a stable state. The glass raw material 4 is efficiently heated by the arc plasma 2 and the combustion flame 3.

[Operation of glass manufacturing equipment]
Next, the operation of the glass manufacturing apparatus 1 according to the embodiment of the present invention will be described with reference to FIG. 6 (refer to FIGS. 1 to 3 as appropriate).

  As shown in FIG. 6, first, the glass manufacturing apparatus 1 starts supplying shield gas to the tip portions 21a and 22a of the arc electrodes 21 and 22 by the shield gas supply means 24 (step S10). Moreover, the glass manufacturing apparatus 1 starts generation | occurrence | production of the swirling flow which descends, rotating along the inner wall 11b of the vitrification space 11a by the swirling flow generation means 40 (step S11).

Next, the glass manufacturing apparatus 1 applies a multiphase AC voltage to the arc electrodes 21 and 22 by the multiphase AC power source 23 to ignite arc discharge, and starts operation of the multiphase AC arc discharge (step). S12).
At the same time, supply of cooling water to the arc electrodes 21 and 22 and the cooling jacket 12 is started, and the operation of an exhaust gas treatment device (not shown) connected to the exhaust port 10a is also started.

  After starting the arc discharge, the glass manufacturing apparatus 1 supplies the multiphase AC power to the arc electrodes 21 and 22 by the multiphase AC power source 23, and the arc plasma 2 generated by the multiphase AC arc discharge is stabilized. The operation of only the multiphase AC arc discharge is continued during the period until (step S13). The period until stabilization is, for example, about 1 to 2 minutes.

  Next, the glass manufacturing apparatus 1 supplies the fuel gas, primary oxygen, and secondary oxygen to the combustion pipe 30 and ignites them to generate the combustion flame 3 (step S14). Then, the hybrid operation is continued until the state of hybrid heating by the combustion flame 3 and the arc plasma 2 disturbed by the ignition of the combustion flame 3 is stabilized (step S15). The period until the hybrid heating state is stabilized is, for example, about 30 minutes to 1 hour.

Next, the glass manufacturing apparatus 1 uses the carrier gas to synchronize the powdery glass raw material 4 with the combustion tube 30 using the carrier gas in synchronism with the change in the high temperature region of the arc plasma 2 by the glass raw material supply means 50 while continuing the hybrid operation. To the glass raw material supply port 30a, and the glass raw material 4 is put into the vitrification space 11a. The charged glass raw material 4 is heated and heated uniformly by the combustion flame 3 and then heated and melted by the hot arc plasma 2 to be vitrified (step S16).
The vitrified glass particles fall into the collection pot 13 and are collected.

  When the vitrification process for the desired glass raw material 4 is completed, the glass manufacturing apparatus 1 stops the supply of the multiphase alternating current from the multiphase alternating current power supply 23 to the arc electrodes 21 and 22 to extinguish the arc discharge, and also burns. The flame 3 is extinguished (step S17).

And the glass manufacturing apparatus 1 stops generation | occurrence | production of the swirl | vortex flow by the swirl | vortex flow generation means 40 (step S18), and stops supply of the shield gas by the shield gas supply means 24 (step S19).
Further, the operation of the exhaust gas treatment device (not shown) is also stopped. The operation of each cooling system is preferably stopped after the temperature of the glass manufacturing apparatus 1 has sufficiently decreased.

As described above, in the glass manufacturing apparatus and the glass manufacturing method according to the present invention, the glass raw material is melted in small granular units, and the glass raw material particles are uniformly heated and melted by the combustion flame, Furthermore, sufficient heat transfer is achieved by exposure to the high-temperature arc plasma formed by the multiphase AC arc, so that the vitrification state is uniform and vitrification with a high vitrification rate can be realized, and the unmelted raw material remains. And inhomogeneous composition and residual reaction product gas are suppressed.
As a result, the vitrification treatment of the glass raw material can be shortened to the order of seconds, and the equipment can be greatly reduced and the energy consumption can be greatly reduced.

Moreover, since the glass manufacturing apparatus according to the present invention can be significantly reduced in size, it is possible to reduce construction costs and reduce the generation of waste when the glass manufacturing apparatus reaches the end of its life.
In addition, according to the present invention, since glass is produced with uniform quality, it is possible to improve the yield in glass production, improve the quality of glass products, and reduce the glass production cost.
In addition, since the present invention can greatly reduce the size of the glass manufacturing apparatus, it is possible to significantly reduce the consumption of waste materials and energy associated with the composition change in the production of a small amount of various types of glass.

Next, examples of the embodiment of the present invention will be described.
First, with reference to FIG. 7, the structure of the glass manufacturing apparatus 1 in a present Example is demonstrated.
The furnace 10 has a cylindrical shape, an inner diameter is 600 [mm], and the outside is covered with a water-cooled cooling jacket 12. The inner surface of the furnace 10 is wound with a heat insulating material 11 having a thickness of 200 [mm], and the inner diameter of the main body of the furnace 10, that is, the diameter of the columnar vitrification space 11a is 200 [mm]. The lid (upper part) of the furnace 10 is also structured as a part of the cooling jacket 12, and the lower part of the lid is burned leaving a space for inserting a cylindrical combustion tube 30 having a diameter of 100 [mm] in the center. The heat insulating material 11 is provided so as to surround the combustion tube 30 up to the outlet of the tube 30. Below the outlet portion of the combustion tube 30, a cylindrical space (vitrification space 11a) having a diameter of 200 [mm] continues to the bottom, and constitutes a main body portion of the furnace 10 in which the vitrification reaction proceeds.

  The tips of the six upper arc electrodes 21 among the arc electrodes 21 and 22 to which 12-phase alternating current is applied are located at a position 300 [mm] below the outlet portion of the combustion tube 30. Further, the tips of the six lower arc electrodes 22 are located approximately 20 [mm] below the tips of the upper arc electrodes 21. The upper arc electrode 21 is inserted into the furnace 10 at an angle of about 30 degrees downward with respect to the horizontal, and the lower arc electrode 22 is inserted into the furnace 10 almost horizontally. Further, as shown in FIG. 2, the six upper arc electrodes 21 and the lower arc electrodes 22 are respectively arranged radially at an angle of 60 degrees in the top view, and the upper arc electrode 21 and the lower arc electrode 22 The side arc electrodes 22 are arranged radially at an angle of 30 degrees as viewed from above.

  Further, in order to generate a swirling flow that descends while rotating along the inner wall of the main body portion of the furnace 10, that is, the inner wall of the heat insulating material 11, an injection is made at a position of 100 mm from the outlet portion of the combustion tube 30. Four gas supply pipes 42 are inserted into the furnace 10 at an angle of about 20 degrees with respect to the horizontal so that the outlet is located. Further, as shown in FIG. 3, the four gas supply pipes 42 are arranged at equal intervals at an angle of 90 degrees in a top view so that gas is ejected in the tangential direction of the inner wall of the furnace 10. There is a spout in the area.

  The vitrification space 11a of the furnace 10 further extends downward from the tip of the lower arc electrode 22 by 400 [mm], and below (collects) glass particles generated in the vitrification space 11a. ) Is provided. The exhaust gas generated in the vitrification space 11 a is sucked to the outside from a nozzle (exhaust port 10 a) provided on the outer wall of the furnace 10, 100 [mm] above the lower end of the main body portion of the furnace 10.

The combustion flame was generated by supplying propane gas as a fuel gas at 6 [NL / min], supplying primary oxygen at 6 [NL / min], and supplying secondary oxygen at 24 [NL / min] and burning.
A 12-phase AC arc plasma was generated using a 12-phase AC as the multi-phase AC. At this time, the arc electrodes 21 and 22 were set so that a current of approximately 100 [A] would flow, and the distance between the tips of the arc electrodes 21 and 22 facing each other was set to 100 [mm].
In this specification, the volume [NL] in the flow rate unit [NL / min] indicates the volume (liter) in the reference state (1 atm, 0 ° C.).

  The electrode arrangement of the arc electrodes 21 and 22 to which the 12-phase AC voltage is applied is the electrode arrangement D described above. In addition, in order to suppress the exhaustion due to the oxidation of the electrodes to each arc electrode 21, 22, argon gas is used as a shielding gas at 5 [NL / min] for a total of 12 arc electrodes 21, 22 in total. 60 [NL / min] was supplied.

  Further, in order to generate a swirl flow to each gas supply pipe 42, nitrogen gas is supplied at 25 [NL / min] for each one and at a total of 100 [NL / min] for the four gas supply pipes 42. did.

As the glass raw material, silica sand (SiO ₂ ) 72 mol%, sodium carbonate (soda ash) 13.5 mol%, calcium carbonate (limestone) 11 mol%, alumina 1.5 mol%, potassium carbonate molded to a particle size of about 0.1 mm A soda-lime glass raw material having a ratio of 1.5 mol% and sodium sulfate (sodium salt) 0.5 mol% was used.
The raw material supply amount was 30 to 80 [g / min], and dry air was supplied at 20 [NL / min] as a carrier gas.

  Further, the supply amount of the carrier gas for charging the glass raw material is changed at 50 Hz which is the same as that of the base AC so as to synchronize with the change in the high temperature region of the 12-phase AC arc, and the glass raw material is intermittently supplied to the vitrification processing space 11a. It was controlled so that it was put in.

  Under the above conditions, the hybrid operation from the ignition of the 12-phase AC arc to the ignition of the combustion flame, and the progress of the vitrification process by supplying the powdery glass raw material, the power supply state to each arc electrode 21, 22 FIG. 8 shows an example of the change with time of the supplied power obtained from the monitoring and recording results. In this result, the output of the 12-phase AC arc during hybrid operation is about 50 [kW]. Although the change with time of this electric power is only the electric power of the 12-phase AC arc, the output of the combustion flame is 9 [kW], and the output is about 60 [kW] in total during the hybrid operation.

  A hybrid type vitrification treatment combining a 12-phase AC arc and a combustion flame under such conditions can obtain a high vitrification rate even when the heating means is only a 12-phase AC arc even under the same energy supply conditions. Can do.

  The ratio of the output of the combustion flame to the 12-phase AC arc is about 1: 5 for the combustion flame: 12-phase AC arc under the conditions of the above-described embodiment. It is possible to maintain a high vitrification rate even if the output of is reduced.

DESCRIPTION OF SYMBOLS 1 Glass manufacturing apparatus 2 Arc plasma 3 Combustion flame 4 Glass raw material 10 Furnace 11 Heat insulating material 11a Vitrification space 11b Inner wall 12 Cooling jacket 12a Cooling water supply port 12b Cooling water discharge port 13 Recovery pot 20 Arc plasma generation means 21 Upper arc electrode (Arc electrode, upper electrode)
21a Tip portion 21b Upper electrode tip circle 22 Lower arc electrode (arc electrode, lower electrode)
22a tip portion 22b lower electrode tip circle 23 shield gas supply means 24 multiphase AC power supply 30 combustion tube 30a glass material supply port 30b fuel gas supply port 30c primary oxygen supply port 30d secondary oxygen supply port 30e cooling water supply port 30f cooling Water discharge port 40 Swirling flow generation means 41 Gas supply source 42 Gas supply pipe 50 Glass raw material supply means 51 Carrier gas supply section 52 Glass raw material supply control means 53 Glass raw material supply device

Claims (7)

A glass manufacturing apparatus that manufactures glass by heating and melting a powdery glass raw material in-flight to vitrify,
A furnace having a vitrification space surrounded by a heat insulating material that is a space for vitrifying the glass raw material;
A combustion pipe that is provided on the upper surface of the vitrification processing space and generates a combustion flame downward;
Arc plasma generating means for generating arc plasma in the vitrification space by applying multi-phase alternating currents having different phases to a plurality of columnar arc electrodes;
A shield gas supply means for supplying a shield gas to the tip of the arc discharge of the arc electrode;
During the combustion flame, glass raw material supply means for supplying the glass raw material from above the generation area of the arc plasma,
A swirl flow generating means for generating a swirl flow that descends while rotating along the inner wall of the vitrification space from above the arc plasma generation region to below the arc plasma generation region;
With
The plurality of arc electrodes are arranged in two upper and lower stages, each of which includes an upper electrode arranged in the upper stage and a lower electrode arranged in the lower stage, each of which is a tip of the arc discharge Is installed downward, and the lower electrode is installed such that the arc discharge tip is horizontally or horizontally upward.
The multiphase alternating current applied to the arc electrode is the phase difference of the alternating current applied to the arc electrodes facing each other across the center of the discharge region, which is the region surrounding the arc discharge tip of the arc electrode when viewed from above. The phase is determined so that is not 180 degrees,
The combustion tube is set so that the combustion flame penetrates the center of the discharge region,
The glass raw material supply means synchronizes with the change in the spread of the high temperature region of the arc plasma generated by the arc plasma generation means, and the glass raw material reaches the generation region of the arc plasma when the high temperature region expands. As described above, the glass raw material is intermittently supplied into the combustion flame at a predetermined timing.
The glass manufacturing apparatus characterized by the above-mentioned.   The glass manufacturing apparatus according to claim 1, wherein the combustion tube is an oxygen burner.   The upper electrode has an arc discharge tip at an angle of 15 degrees to 45 degrees with respect to the horizontal, and the lower electrode has an arc discharge tip of 0 degree with respect to the horizontal. The glass manufacturing apparatus according to claim 1 or 2, wherein the glass manufacturing apparatus is installed at an angle of 10 degrees or less.   The upper electrode and the lower electrode are arranged radially such that the arc discharge tips are positioned on concentric circles of a predetermined diameter in the glass processing space, respectively, and the arc discharge tips of the upper electrode are arranged. The diameter of the concentric circle located is smaller than the diameter of the concentric circle where the tip of arc discharge of the lower electrode is located, The glass manufacturing device according to any one of claims 1 to 3 characterized by things. Each of the upper electrode and the lower electrode has six arc electrodes, which are arranged radially at an angle of 60 degrees in a top view, and the upper electrode and the lower electrode adjacent to each other are: Arranged at an angle of 30 degrees in top view,
The multi-phase alternating current is a 12-phase alternating current, and in the twelve arc electrodes arranged at an angle of 30 degrees in a top view, the phase of the alternating current applied to one arc electrode and the one in the top view The 12-phase alternating current is applied to the arc electrode so that the difference between the arc electrode and the phase of the alternating current applied to any one of the second to fourth adjacent arc electrodes is 180 degrees. The glass manufacturing apparatus as described in any one of Claim 1 thru | or 4.   6. The rotation direction of the arc plasma, the rotation direction of the combustion flame, and the rotation direction of the swirl flow in a plan view are the same direction, 6. The glass manufacturing apparatus as described in. It is a glass manufacturing method using the glass manufacturing apparatus as described in any one of Claim 1 thru | or 6 which manufactures glass by heat-melting a powdery glass raw material in-flight, and vitrifying,
Supplying the glass raw material into the combustion flame;
Heating the glass material with the combustion flame;
Heating the glass material heated by the combustion flame with the arc plasma;
The glass manufacturing method characterized by including.

Images