JP2009132555A - Apparatus for heating very pure glass articles, and method of processing very pure glass articles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for heating very pure glass articles and a method of processing very pure glass articles capable of preventing foreign matter generated from members in a furnace case from being carried and attached to a glass preform by the purge gas in the furnace case. <P>SOLUTION: In the apparatus 31 for heating very pure glass articles by heating a cylindrical heating body 16, through which the very pure glass articles are to be inserted, by electro-magnetic induction by induction coils arranged around its outer circumference to carry out a prescribed heat treatment onto the glass preform; attachment of foreign matter by the purge gas in the furnace case can be prevented by blocking the very pure glass articles from the purge gas in the furnace case by providing a contaminating substance-blocking cylinder 33 made from a high purity carbon and air-tightly surrounding the outer circumference of the very pure glass articles from the inlet 11 of the apparatus to the outlet 12 of the apparatus in the inner peripheral side of the cylindrical heating body 16. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heating device for high-purity glass articles and a processing method for high-purity glass articles.

  As one method for producing a glass preform for an optical fiber which is an example of a high-purity glass article, a glass tube serving as a cladding layer and a glass rod serving as a core layer are separately manufactured, and then the glass tube contains glass. A so-called rod-in-tube method has been proposed in which a rod is inserted, heated, and welded and integrated (hereinafter referred to as collapse).

As shown in FIG. 5, as a glass base material manufacturing apparatus that performs such collapse, both ends of the glass base material 3 inserted into the heating device 2 on the base 1 are connected to a pair of bases 1 on the base 1. Heated as indicated by an arrow X in the figure while being held by the base material gripping chucks 5 and 6 and rotating the glass base material 3 by the rotational force transmitted to the glass base material 3 from the base material gripping chucks 5 and 6 side. It is known that the apparatus 2 is sequentially moved in the axial direction of the glass base material 3 and the glass base material 3 is collapsed sequentially from one end side thereof.
In the case of the manufacturing apparatus shown in FIG. 5, a preheating burner 8 for preheating the glass base material 3 is provided adjacent to the heating apparatus 2.

  As the heating apparatus 2 used in such a manufacturing apparatus, an induction heating type heating apparatus (so-called induction furnace) is used because it is required that the heating temperature can be quickly switched and temperature control is easy. There are many cases. Note that the induction furnace has a steeper temperature gradient than the resistance furnace, and thus is easy to collapse. Further, when collapsing with an oxyhydrogen burner, OH enters the glass, but when an induction furnace is used, OH does not enter.

FIG. 6 shows a conventional induction heating type heating device used as the heating device 2 described above.
The configuration of the heating device 2 is disclosed in the following Patent Document 1 and the like, and the glass base material 3 is inserted into the furnace case 14 in which the device inlet 11 and the device outlet 12 through which the glass base material 3 is inserted are formed. And a induction coil 17 disposed on the outer periphery of the heating element 16 and generating heat by electromagnetic induction.

The furnace case 14 is supported by the base 1 so as to be movable in the axial direction of the glass base material 3 as indicated by an arrow X in the figure.
Both ends of the heating element 16 are supported by the furnace case 14 via an insulating material 18.
Further, a heat insulating material 19 that suppresses heat radiation from the heating element 16 is provided between the heating element 16 and the induction coil 17.
The furnace case 14 is purged with an inert gas in order to suppress oxidation reactions of the in-furnace parts due to high temperatures.

JP 2003-192369 A

However, when the glass base material 3 heat-treated by the conventional heating device 2 shown in FIG. 6 is subjected to component analysis of the metal component in the base material surface layer (layer having a thickness of about 400 μm from the base material surface), FIG. As shown in the graph, the peak values p1 and p2 are generated in the Cu (copper) content graph g1 and the Zn (zinc) content graph g2, and the adhesion of these metal powders (fine particles) occurs. It was confirmed that
In practice, it is also detected that iron, nickel, chromium, and aluminum are attached to the surface layer of the base material in addition to the above copper and zinc.

If these deposits are left as they are, they will cause an increase in transmission loss in the optical fiber, leading to defective optical fiber products.
Therefore, if a step of removing the foreign matter adhering to the surface of the glass base material 3 by the peripheral grinding of the glass base material after the heat treatment by the heating device 2 is provided, the product cost increases due to the addition of the peripheral grinding. The problem that occurred.

The inventor of the present application has investigated the cause of the adhesion of the metal component in order to prevent the adhesion of the metal component as described above.
As a result, the following was found.
In order to allow thermal expansion, it is indispensable to secure a gap between the heating elements 16 and the insulating material 18 adjacent in the furnace case 14, and as shown by an arrow A in FIG. The purge gas in the furnace case 14 enters the glass base material 3 side through the gap.
For this reason, the metal impurity generated in the furnace case 14 is carried to the glass base material 3 side by the purge gas, and is attached to the surface of the glass base material 3.

  It is an object of the present invention to solve the above-mentioned problems, and that foreign matter generated from a member in the furnace case is carried to the high purity glass article by the purge gas in the furnace case, and the foreign matter adheres to the high purity glass article. Therefore, it is possible to prevent the high-purity glass article after the heat treatment from becoming defective due to the adhesion of foreign matter, or the increase in product cost due to the removal processing of the attached foreign matter. It is an object of the present invention to provide a heating device for high-purity glass articles and a method for processing high-purity glass articles.

(1) In order to solve the above-described problems, a heating apparatus for high-purity glass articles according to the present invention is configured to electromagnetically induce a cylindrical heating element through which a high-purity glass article is inserted by an induction coil disposed on the outer periphery thereof. A high-purity glass article heating device that generates heat by performing a predetermined heat treatment on the high-purity glass article,
A pollutant made of high-purity carbon that hermetically surrounds the outer periphery of the high-purity glass article on the inner peripheral side of the cylindrical heating element and from the apparatus entrance to the apparatus exit for allowing the high-purity glass article to enter and exit the apparatus A shielding cylinder is provided.

  (2) Moreover, the heating apparatus for high-purity glass articles described in the above (1) may be characterized in that the contaminant shielding cylinder has a cylindrical structure with a thickness of 5 mm or less.

  (3) In addition, in the heating device for high-purity glass articles described in (2) above, an inert gas is supplied from the entire periphery of the cylinder toward the axial center of the cylinder almost uniformly from both ends of the pollutant shielding cylinder. A gas supply ring for supplying may be provided.

  (4) Further, in the heating device for high-purity glass articles described in (3) above, a cylindrical gas induction tube is installed inside the gas supply ring with a predetermined gap, and is supplied from the gas supply ring. The inert gas flow may be caused to flow between the gas guide cylinder and the pollutant shielding cylinder, and then the gas may be caused to flow along the inner peripheral surface of the pollutant shielding cylinder.

  (5) In order to solve the above-described problem, a high-purity glass article processing method according to the present invention uses a heating device according to any one of the above (1) to (4) to provide a high-purity glass. The article is heated.

According to the heating apparatus for high-purity glass articles and the processing method for high-purity glass articles according to the present invention, the high-purity glass article inserted into the heating apparatus has a section from the apparatus entrance to the apparatus exit, and its outer periphery is shielded from contaminants. Since it is surrounded by a cylinder and is blocked by various contaminant shielding cylinders from various members in the furnace case, which is the outer wall of the device, foreign matter generated from various members in the furnace case It is possible to prevent foreign substances from adhering to the glass base material by being carried to the glass base material by the purge gas.
Accordingly, it is possible to prevent the disadvantage that the glass base material after the heat treatment becomes defective due to the adhesion of foreign matters, and it is possible to produce high-quality high-purity glass articles with a high yield.
In addition, since it is possible to prevent foreign matter from adhering to the high-purity glass article during heat treatment, it is not necessary to remove the attached foreign matter and prevent the occurrence of inconveniences such as increased product costs due to the foreign matter removal processing. It is possible to reduce the product cost.

Hereinafter, preferred embodiments of a heating device for a high-purity glass article and a method for processing a high-purity glass article according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a heating device for a glass preform for an optical fiber, which is an embodiment of a heating device for high-purity glass articles according to the present invention, and FIG. 2 is a pollutant shielding cylinder in the heating device shown in FIG. FIG. 3 is an explanatory diagram of the gas flow by the gas supply ring and the gas induction cylinder attached to the end of the gas flow. FIG. 3 shows the gas flow by the gas supply ring attached to the end of the pollutant shielding cylinder in the heating apparatus shown in FIG. FIG. 4 is an explanatory diagram and FIG. 4 is a graph showing the component analysis results regarding Cu and Zn in the surface layer of the glass base material heat-treated by the heating apparatus of FIG.

  A heating device 31 shown in FIG. 1 is an induction furnace suitable for a collapse process in which a glass tube and a glass rod inserted between the glasses are heated and integrated in a so-called rod-in-tube method. In addition, for example, it can be used for heating applications such as stretching and drawing.

  The heating device 31 is a cylindrical heat generating member through which the glass base material 3 is inserted into a furnace case 14 as an outer wall of the device in which the device inlet 11 and the device outlet 12 through which the glass base material 3 which is a high-purity glass article is inserted. A body 16 and an induction coil 17 disposed on the outer periphery of the heating element 16 and generating heat by electromagnetic induction are provided.

As indicated by an arrow X in the figure, the furnace case 14 is supported so as to be movable in the axial direction of the glass base material 3.
Both ends of the heating element 16 are supported by the furnace case 14 via an insulating material 18.
Further, a heat insulating material 19 that suppresses heat radiation from the heating element 16 is provided between the heating element 16 and the induction coil 17.
The furnace case 14 is purged with an inert gas in order to suppress oxidation reactions of the in-furnace parts due to high temperatures.

  In the case of the heating device 31 of the present embodiment, the outer periphery of the glass base material 3 from the device inlet 11 to the device outlet 12 through which the glass base material 3 enters and exits the device on the inner peripheral side of the cylindrical heating element 16 A high-purity carbon-made pollutant shielding cylinder 33 is provided.

The pollutant shielding cylinder 33 has a cylindrical structure with a thickness of 5 mm or less.
Further, as shown in FIGS. 2 and 3, the pollutant shielding cylinder 33 is substantially evenly spaced from the entire periphery of the contaminant shielding cylinder 33 at both ends of the contaminant shielding cylinder 33 located at the apparatus inlet 11 and the apparatus outlet 12. A gas supply ring 35 for supplying an inert gas toward the axis center is provided.

  Further, as shown in FIG. 2, a cylindrical gas guide cylinder 37 is installed inside the gas supply ring 35 with a predetermined gap. By this gas guide tube 37, the inert gas flow supplied from the gas supply ring 35 is caused to flow between the gas guide tube 37 and the pollutant shielding tube 33, and then is caused to flow over the inner peripheral surface of the pollutant shield tube 33. Gas is flowing.

As shown in FIG. 3, the gas supply ring 35 has a structure in which a plurality of gas injection holes 35 b are formed at equal intervals in the circumferential direction on the inner periphery of the hollow ring 35 a that circulates around the open end of the contaminant shielding cylinder 33. As shown by an arrow C in FIG. 3, the inert gas supplied from the external gas supply path 38 into the hollow ring 35 a is injected from the gas injection hole 35 b toward the axial center of the contaminant shielding cylinder 33.
The gas injection holes 35b are set in the number of arrays and the interval between the holes so that the supply of the inert gas is uniform at any position in the circumferential direction of the contaminant shielding cylinder 33.
As a specific example, the gas injection holes 35b are holes having a diameter of 2 mm formed in a row in the circumferential direction on the inner periphery of the hollow ring 35a. Is done.

As shown in FIGS. 1 and 2, the gas guiding cylinder 37 has a cylindrical portion 37a installed with a gap of about 0.5 mm inside the pollutant shielding cylinder 33, and a diameter from the end of the cylindrical portion 37a. 2 is provided with a sealing flange portion 37b extending outward in the direction and in airtight contact with the outer end surface of the hollow ring 35a. As shown by an arrow D in FIG. The injected inert gas flow is redirected to a gas flow along the inner peripheral surface of the pollutant shielding cylinder 33.
The above gas guide cylinder 37 is formed of any material of carbon, ceramic, and quartz. The axial length of the cylindrical portion 37a of the gas guiding cylinder 37 is set to about 50 to 100 mm.

The inert gas flow supplied to the openings at both ends of the pollutant shielding cylinder 33 by the gas supply ring 35 is redirected by the gas guiding cylinder 37 to a gas flow along the inner peripheral surface of the pollutant shielding cylinder 33, and FIG. As shown by the solid line arrow B, after flowing to the middle part of the pollutant shielding cylinder 33, it is exhausted to the outside from the apparatus inlet 11 and the apparatus outlet 12.
In FIG. 1, the inert gas flow supplied to the openings at both ends of the pollutant shielding cylinder 33 by the gas supply ring 35 is shown to collide with the counterflow at the middle portion of the pollutant shielding cylinder 33 and turn back. However, it is considered that there is a case where the air is exhausted to the outside from the previous apparatus inlet 11 and apparatus outlet 12 without colliding.

  On the other hand, the inert gas supplied to the furnace case 14 for purging in the furnace case 14 flows from the outer periphery to the inner periphery of the furnace case 14 as indicated by the broken arrow E in FIG. Although it goes to the glass base material 3 side through the gap between the body 16 and the insulating material 18, the glass base material 3 side is cut off by the pollutant shielding cylinder 33, and therefore along the outer periphery of the pollutant shielding pipe 33. Then, the gas flows to the apparatus inlet 11 and the apparatus outlet 12 side, and is exhausted to the outside from an exhaust port (not shown) secured between the gas supply ring 35 and the furnace case 14.

When the contaminant shielding cylinder 33 made of high-purity carbon is in contact with oxygen, the exhaustion of oxidation starts at about 400 ° C. or higher. However, as in the above-described embodiment, when contact with oxygen is avoided by flowing an inert gas on the surface, oxidation exhaustion can be prevented up to about 3000 ° C. Therefore, it is possible to suppress deterioration due to oxidation consumption of the pollutant shielding cylinder 33 and reduce the replacement frequency of the pollutant shielding cylinder 33, thereby reducing the maintenance cost and improving the apparatus operating rate.
Moreover, although the pollutant shielding cylinder 33 is made of high-purity carbon, it contains about 1 ppm of metal impurities. However, as described above, the inert gas supplied by the gas supply ring 35 and the gas guide cylinder 37 suppresses the deterioration of the pollutant shielding cylinder 33 due to oxidation consumption, so that the metal contained in the pollutant shielding cylinder 33 itself is contained. The emission of impurities is prevented, and the glass base material 3 can be more thoroughly prevented from being contaminated.
In addition, since it explains supplementarily, since the gas supply ring 35 and the gas induction cylinder 37 are arrange | positioned in the position where temperature is comparatively low, a foreign material does not generate | occur | produce from these components.

Since the inert gas for purging in the furnace case 14 and the inert gas supplied into the pollutant shielding cylinder 33 by the gas supply ring 35 are usually cheaper than argon gas, nitrogen is used. Gas is used.
However, in order to prevent the cyanation of nitrogen gas at a high temperature, argon gas may be used instead of nitrogen gas when the ambient temperature for supplying the inert gas exceeds 2200 ° C.
The amount of inert gas supplied from the gas supply ring 35 is, for example, about 20 liters per minute, and the flow rate of the inert gas flow on the inner peripheral surface of the contaminant shielding cylinder 33 by the gas guiding cylinder 37 is about 2 to 4 m / s. Then, the oxygen concentration at the furnace center in the pollutant shielding cylinder 33 can be maintained in a good state of about 20 to 50 ppm.

  According to the heating device 31 of the present embodiment described above, the optical fiber glass base material 3 as a high-purity glass article inserted into the device is a section from the device inlet 11 to the device outlet 12, and its outer periphery. Is surrounded by the pollutant shielding cylinder 33 and is blocked by the pollutant shielding cylinder 33 from the various members in the furnace case 14 which is the outer wall of the apparatus. It is possible to prevent the generated foreign matter from being carried to the glass base material 3 by the purge gas in the furnace case 14 and attaching the foreign matter to the glass base material.

Accordingly, it is possible to prevent the disadvantage that the glass base material 3 after the heat treatment becomes a product defect due to adhesion of foreign matters, and it is possible to produce a high-quality optical fiber glass base material with a high yield.
In addition, foreign matter can be prevented from adhering to the optical fiber glass preform during the heat treatment, so there is no need to remove the adhering foreign matter and prevent the occurrence of inconveniences such as increased product costs due to the foreign matter removal processing. It is possible to reduce the product cost.

In order to confirm the foreign matter adhesion preventing effect, the inventors of the present application conducted a component analysis of the metal component in the surface layer of the base material of the glass base material 3 heat-treated with the heating device 31 of the above-described embodiment. As shown in FIG. 7, the peak values as shown in FIG. 7 do not appear in the Cu (copper) content graph g1 or the Zn (zinc) content graph g2, and the adhesion of these metal powders (fine particles) does not occur. It was confirmed that it was prevented.
Furthermore, in addition to the above copper and zinc, the component analysis of the metal component in the base material surface layer is performed, and the heat treatment after the countermeasure according to the above embodiment and the heat treatment before the countermeasure (conventional heating device), The contamination concentration by various metal components on the base material surface layer was compared.
The following Table 1 shows the measurement results.

  As shown in Table 1, even in iron, nickel, chromium, aluminum, etc. other than copper and zinc, it can be confirmed that the contamination is reduced by the above embodiment, and the usefulness of the above embodiment is confirmed. I was able to.

Further, in the above embodiment, the pollutant shielding cylinder 33 has a cylindrical structure made of high-purity carbon having a thickness of 5 mm or less. With this thickness, the influence of induction heating of the pollutant shielding cylinder 33 itself is small. Deterioration of the pollutant shielding cylinder 33 due to heating can be prevented.
Further, in the case of the thickness of the pollutant shielding cylinder 33 of 5 mm or less, the heat capacity itself of the pollutant shielding cylinder 33 can be kept small, so that the heating energy to be transmitted to the glass base material 3 has little influence and heat generation. A decrease in heating efficiency due to the body 16 can also be suppressed.

Further, in the heating device 31 of the present embodiment, the inner peripheral surface of the pollutant shielding cylinder 33 is covered with an inert gas supplied into the pollutant shielding cylinder 33 by the gas supply ring 35 and the gas guiding cylinder 37, Further, the outer peripheral surface of the pollutant shielding cylinder 33 is also covered with an inert gas used for purging in the furnace case 14. That is, each of the inner peripheral surface and the outer peripheral surface of the pollutant shielding cylinder 33 is covered with an inert gas, and contact of oxygen with the surface of the pollutant shielding cylinder 33 is avoided. Oxidation consumption can be satisfactorily prevented, deterioration due to oxidation consumption of the pollutant shielding cylinder 33 can be suppressed, and the replacement frequency of the pollutant shielding cylinder 33 can be reduced, thereby reducing maintenance costs and improving the apparatus operating rate.
Further, as described above, the suppression of deterioration due to oxidative consumption of the pollutant shielding cylinder 33 prevents the release of metal impurities contained in the pollutant shielding cylinder 33 itself, thereby further preventing the contamination of the glass base material 3. be able to.

In the heating device for high-purity glass articles according to the present invention, the structure of both ends of the contaminant shielding cylinder is not limited to the above embodiment.
For example, both ends of the pollutant shielding cylinder 33 are equipped with only the gas supply ring 35 shown in the above embodiment, and the gas guiding cylinder 37 is omitted, thereby reducing the apparatus cost by reducing the number of components. be able to.
However, when the inert gas supply at both ends of the pollutant shielding cylinder 33 is performed only by the gas supply ring 35 as described above, contact with oxygen on the inner peripheral surface of the pollutant shielding cylinder 33 is avoided. The performance is lower than that in the above embodiment, the deterioration of the pollutant shielding cylinder 33 due to oxidation consumption is faster than in the above embodiment, and the replacement frequency of the pollutant shielding cylinder 33 is higher than that in the above embodiment. Get higher.

Moreover, in the heating apparatus for high-purity glass articles of the present invention, the foreign matter generated from various members in the furnace case 14 is carried to the glass base material 3 by the purge gas in the furnace case 14 and the foreign matter adheres to the glass base material. If only an effect is required to prevent this, both the gas supply ring 35 and the gas guide tube 37 described in the above embodiment may be omitted.
However, when both the gas supply ring 35 and the gas guide cylinder 37 are omitted, the inner peripheral portion of the pollutant shielding cylinder 33 is more easily deteriorated due to oxidation consumption than the case where only the gas supply ring 35 is provided. The frequency of exchanging the pollutant shielding cylinder 33 is increased.

In the measurement test by the inventors of the present application, in the configuration in which the gas supply ring 35 and the gas guide tube 37 are provided at both ends of the pollutant shielding cylinder 33 as in the above embodiment, the center of the furnace in the pollutant shielding cylinder 33 is used. The oxygen concentration in can was kept at 20-50 ppm, and the daily operation could be repeated 30 times or more without replacing the pollutant shielding cylinder 33.
Here, the above-mentioned one-day operation is an operation condition in which the heat treatment is repeatedly performed 3 to 4 times a day after the heating element 16 is heated to about 2000 ° C. and held for 3 to 5 hours. Means.

  On the other hand, in the case where only the gas supply ring 35 is provided at both ends of the pollutant shielding cylinder 33, the oxygen concentration in the center of the furnace in the pollutant shielding cylinder 33 is 400 to 5000 ppm, and the operation is performed for one day. It was found that after repeating about 10 times, it is necessary to replace the pollutant shielding cylinder 33. As a result, it has been found that the effect of the gas guide tube 37 is remarkable.

  Further, when neither the gas supply ring 35 nor the gas guide tube 37 is provided at both ends of the pollutant shielding cylinder 33, the oxygen concentration in the furnace center in the pollutant shielding cylinder 33 is equal to that in the atmosphere. It became about 18%, and it turned out that it is necessary to replace the pollutant shielding cylinder 33 every day of operation. Thus, it has been found that the effect of the gas supply ring 35 is also remarkable.

  In addition, the articles | goods heat-processed with the heating apparatus which concerns on this invention are not restricted to the glass preform | base_material for optical fibers shown in the said embodiment. Various high-purity glass articles that are important requirements for preventing the adhesion of foreign matters can be heated.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the heating apparatus of the glass preform for optical fibers used as one embodiment of the heating apparatus for high-purity glass articles according to the present invention. It is explanatory drawing of the gas flow by the gas supply ring and gas induction cylinder with which the edge part of the contaminant shielding cylinder in the heating apparatus shown in FIG. 1 was mounted | worn. It is explanatory drawing of the gas flow by the gas supply ring with which the edge part of the contaminant shielding cylinder in the heating apparatus shown in FIG. 1 was mounted | worn. It is a graph which shows the component analysis result regarding Cu and Zn of the surface of the glass base material heat-processed with the heating apparatus of FIG. It is explanatory drawing of schematic structure of the manufacturing apparatus of the conventional glass base material. It is a schematic block diagram of the heating apparatus used for the manufacturing apparatus of FIG. It is a graph which shows the component analysis result regarding Cu and Zn of the surface of the glass base material heat-processed with the heating apparatus of FIG.

Explanation of symbols

3 Glass base material for optical fiber (high-purity glass article)
DESCRIPTION OF SYMBOLS 11 Apparatus inlet 12 Apparatus outlet 14 Furnace case 16 Heating element 17 Induction coil 18 Insulation material 19 Heat insulating material 31 Heating apparatus (induction furnace)
33 Pollutant shielding cylinder 35 Gas supply ring 37 Gas induction cylinder

Claims (5)

A heating device for high-purity glass articles that heats a cylindrical heating element through which a high-purity glass article is inserted by electromagnetic induction by an induction coil arranged on the outer periphery of the cylindrical heating element and performs a predetermined heat treatment on the high-purity glass article Because
A pollutant made of high-purity carbon that hermetically surrounds the outer periphery of the high-purity glass article on the inner peripheral side of the cylindrical heating element and from the apparatus entrance to the apparatus exit for allowing the high-purity glass article to enter and exit the apparatus A heating apparatus for high-purity glass articles, comprising a shielding cylinder.   The heating apparatus for high-purity glass articles according to claim 1, wherein the pollutant shielding cylinder has a cylindrical structure with a wall thickness of 5 mm or less.   3. A gas supply ring for supplying an inert gas from the entire circumference of the cylinder toward the axial center of the cylinder is provided at both ends of the pollutant shielding cylinder. The heating apparatus for high-purity glass articles described in 1.   A cylindrical gas guide tube is installed inside the gas supply ring with a predetermined gap, and an inert gas flow supplied from the gas supply ring is placed between the gas guide tube and the contaminant shielding tube. The heating apparatus for high-purity glass articles according to claim 3, wherein the gas is allowed to flow, and then the gas is caused to flow over the inner peripheral surface of the pollutant shielding cylinder.   A method for processing a high-purity glass article, comprising heating the high-purity glass article using the heating device according to any one of claims 1 to 4.

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