JPH0379606B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a quartz glass burner having a multi-tube structure, and particularly to a quartz glass burner capable of producing a large-diameter flame with high thermal power.

"Conventional technology" Quartz glass has excellent optical, thermal, and chemical properties, so it is used for a variety of purposes, but in recent years its use has expanded to electronics such as optical fibers and the semiconductor industry. As the field expanded, higher purity and precision were required.

Conventionally, metal oxyhydrogen burners have been used as jigs for heat treatment and processing of quartz glass, but when metal burners are used, metal vapor released from the metal is released. There is a problem in that the oxides thereof adhere to the surface of the quartz glass together with the gas flow or the flame flow, making it impossible to obtain a high-purity product.

For this reason, a method of processing using a quartz glass burner instead of the metal burner has been proposed in recent years, but unlike metals, precise cutting of silica glass is difficult, so tubular bodies are generally used. The tubular body was formed by thermal processing such as bending, reducing or expanding the diameter, or welding while heating the tubular body.

For example, in this type of quartz glass burner, a plurality of pipes with different cross-sectional diameters are arranged concentrically, combustion gas and oxygen gas are introduced into the pipes, and both gases are introduced from the outlet at the tip side. Conventionally, a gas burner with a concentric tube structure was used, which performs external mixing while blowing out oxygen gas.However, in such a concentric tube structure, the larger the diameter of the outlet, the more the oxygen gas ejected from the inner tube and the outside are mixed. The hydrogen gas ejected from the cylinder was not sufficiently mixed, and strong firepower could not be obtained.

In order to eliminate such drawbacks, the present applicant first developed an outer cylinder whose diameter was enlarged on the outlet side to conduct combustion gas, and a conduit inserted into the outer cylinder to conduct combustion-supporting gas. quartz, wherein the combustion-supporting gas pipe line is bulged along the enlarged diameter portion on the outlet side of the outer cylinder, and a large number of branch pipes are extended from the end side of the bulged portion toward the outlet side. We suggest a glass burner. (Utility Application No. 61-140553) According to this prior art, the diameter of the outlet side of the outer cylinder 1 made of quartz glass through which combustion gas is conducted is enlarged,
Although a large-diameter combustion gas outlet is formed, a large number of branch pipes that communicate with combustion-supporting gas pipes for supporting the combustion of combustion gas are inserted into the enlarged-diameter part, which prevents oxygen deficiency. In particular, in the prior art, combustion gas and combustion-supporting gas are respectively led out into the combustion-supporting gas pipe. By inserting a double pipe and extending the double pipe along the central axis of the outlet, it is possible to eject a mixed flow from the center of the outlet. It has the effect of being able to obtain strong firepower even though it has a large diameter, and that the flame length and firepower can be easily adjusted by opening/closing or controlling the gas supply to the double pipe.

``Problems to be Solved by the Invention'' However, in this prior art, the combustion-supporting gas pipe and a number of branch pipes scattered within the outer cylinder are connected via an expansion part. Therefore, the combustion gas introduced to the outlet side is introduced to the inner wall side of the outlet through the air gap formed on the outer peripheral side of the expansion part, and of course the combustion gas also flows around to the center side of the outlet. The amount is relatively small compared to the inner wall side, and it has been difficult to obtain a flame flow with an even flame distribution.

For this reason, in the prior art, a double pipe from which combustion gas and combustion-supporting gas are respectively led out is inserted in the center of the outlet, so that a strong thermal power can be ejected from the center. The double pipe merely has an auxiliary role in correcting uneven flame distribution and is not a basic solution.

In addition, when manufacturing a preform to be used as a master tube for manufacturing an optical fiber, a step of cutting the preform with a burner after heat treatment is included, but the double tube incorporated in the burner in the prior art is Since it is an external mixing type, it is difficult to obtain a flame flow strong enough to cut the large quartz glass material that is the workpiece, and in this respect, its function as a burner is lacking. .

In view of such technical requirements, the present invention has been developed using quartz glass that can smoothly form a large-diameter flame flow with an even flame distribution without reducing the thermal power while forming a large-diameter combustion gas outlet. The goal is to provide burners.

Another object of the present invention is to provide a quartz glass burner that can easily adjust the flame length and can form a strong flame stream of small diameter necessary for cutting.

"Means for Solving the Problems" In order to achieve the above technical problems, the present invention provides an expansion portion 8 as shown in FIGS. 1 and 2 C and E.
One or more bypass passages 14 are provided on the combustion-supporting gas pipe 2 located on the inlet side or the upstream side of the pipe 2 from the outer circumferential side to the inner circumferential side of the pipe line 2. The introduced combustion gas is transferred to the expansion section 8.
It is configured such that it can be distributed to the inner circumferential side of the bulging portion 8 through the bypass passage 14, and the combustion gas and combustion supporting gas are distributed along the central axis of the outlet on the inner circumferential side of the expanding portion 8. An internal mixing means 5 which extends a mixed gas pipe in which a combustible gas is mixed, and mixes combustion gas and combustion supporting gas by an aspirator action via a throttle passage 62 on the upstream side of the mixed gas pipe 6. We propose a quartz glass burner equipped with

Furthermore, the present invention is not limited to oxyhydrogen burners, but can be easily applied to burners that use other combustion gases, and even burners that use chlorine gas as the combustion-supporting gas.

Furthermore, it is obvious that the member to be heated by the burner is not limited to only quartz glass members, but can also be used to heat silicon and other semiconductors.

"Operation" According to this technical means, the combustion gas is not supplied to the center side of the outlet while going around the outer periphery of the expansion part, but the distribution means 14 is provided at least on the inlet side of the expansion part 8, Since the combustion gas is directly supplied to the outer circumferential side and the inner circumferential side of the bulging portion 8 by the distribution means 14, as in the prior art, the amount of combustion gas supplied to the center side of the outlet 7 is reduced by the amount of combustion gas supplied to the center side of the outlet 7. The amount of gas supplied to the inner wall side (the outer circumferential side of the expansion part) is not relatively small compared to the amount of gas supplied to the inner wall surface side (the outer peripheral side of the expansion part), and the combustion gas introduced into the outer cylinder 1 is distributed centrally to the peripheral edge of the outlet. The fuel gas can be evenly introduced to each side, and as a result, it is possible to form a large-diameter flame flow with an even flame distribution in the cross-sectional direction of the outlet 7.

In this case, the gas is not introduced into the outer circumferential side and the inner circumferential side of the bulging part 8 separately, but the distribution means (bypass passage 14) located at least on the inlet side of the bulging part 8 is introduced from one conductive passage 10. Since the structure is such that distribution is performed through the pipe, the internal pipe configuration is simplified accordingly.

In particular, in the present invention, since the bulging portion and the combustion-supporting gas pipe 2 connected thereto are formed to have a hollow ring shape in cross section, the formation of the bypass pipe 14 is facilitated. The combustion gas introduced from the combustion gas introduction pipe 11 into the ring-shaped conduit 10 in the outer cylinder 1 is supplied to the inner peripheral wall side of the outlet 7 through the outer peripheral side 81 of the expansion part 8, and A part of the combustion gas introduced into the ring-shaped conduit 10 is also introduced into the inner peripheral side 82 of the expansion section 8 through the bypass path 14, and is also supplied to the center side of the outlet 7. It becomes possible to configure.

Further, in a preferred embodiment of the present invention, a mixed gas pipe for blowing out a mixed gas in which combustion gas and combustion-supporting gas are mixed is provided to extend along the central axis of the outlet on the inner peripheral side of the expansion part. Therefore, the flame length and heating power can be easily adjusted as in the prior art, and in particular, in the present invention, the internally mixed mixed flow can be ejected from the mixed gas pipe by the aspirator action. Because of this structure, it is possible to form a flame flow that is more powerful and has a smaller diameter than the double pipe of the prior art, and since the mixed gas pipe is a single pipe, its diameter can be freely changed. and can be easily adjusted.

Moreover, by blowing out the mixed flame only from the mixed gas pipe after heat treatment or processing with this burner, it is possible to easily cut large workpieces, which was difficult with double pipes. Therefore, a series of operations from processing or heat treating a large workpiece to cutting it can be easily performed with one burner.

Furthermore, in the present invention, since the mixed gas is formed by the action of an aspirator, the mixing ratio can be easily adjusted, and the flame length and heating power can be adjusted even more easily.

Furthermore, since the mixed gas pipe and the internal mixing means communicate through the throttle passage, even if a backfire occurs, for example, it will be blocked by the throttle passage, and there is no risk of backfire reaching the internal mixing means. , which is also preferable in terms of safety.

"Embodiments" Hereinafter, preferred embodiments of the present invention will be described in detail by way of example with reference to the drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described in this example are as follows, unless otherwise specified.
This is not intended to limit the scope of the invention, but is merely an illustrative example.

FIG. 1 is a partially cutaway front view showing an oxyhydrogen burner for processing quartz glass according to an embodiment of the present invention, and FIG.
Figures A to 2D show each part of Figure 1 (A-A', B-B',
C-C', D-D', E-E').

The oxyhydrogen burner according to the present embodiment has a combustion-supporting gas pipe 2 concentrically inserted into an outer cylinder 1 made of quartz glass into which hydrogen gas is introduced, and further has oxygen in the gas pipe 2. Double pipes 3 and 4 through which gas and hydrogen gas are conducted are inserted concentrically, and the tips of the double pipes 3 and 4 are connected to a mixed gas pipe line 6 via an internal mixing means 5. There is.

The outer cylinder 1 has a straight shape, and a hydrogen gas introduction pipe 11 is connected to the peripheral edge of the inlet end side of the outer cylinder 1.
A cylindrical dome-shaped air outlet 7 is formed by gradually expanding the diameter of the outlet side of the outer cylinder 1 and gradually decreasing the diameter of the tip side thereof, and the outlet end of the air outlet 7 is flush with the surface. The outlet 7 is extended slightly forward from the opening end of the branch pipe formed in the opening end, and the extended portion 7a is reduced in diameter toward the center.
The configuration is such that the hydrogen gas spouted out can be focused toward the center.

The combustion-supporting gas pipe line 2 includes an outer circumferential pipe 21 and an inner circumferential pipe 22.
The inlet end side thereof is connected to the oxygen gas introduction pipe 23, and the outer circumferential tube 21 and the inner circumferential tube 22 are concentrically connected to the outer cylinder 1 in a straight line up to the inlet end of the air outlet 7. After extending the outer peripheral pipe 21
The inner circumferential tube 22 is extended almost parallel to the center line, and the maximum diameter part of the outlet 7 is expanded. Ring plate-shaped sealing surface 2 at approximately corresponding positions
4 to seal. As a result, an expansion portion 8 having a hollow annular cross-section and concentric with the outlet 7 is formed on the forward side of the combustion-supporting gas pipe 2 along the enlarged diameter portion of the outlet 7. (See FIG. 2 E-E') Furthermore, on the inlet side of the expansion section 8, a plurality of bypass pipes 14 are inserted along the circumferential direction, penetrating the walls of the outer circumferential tube 21 and the inner circumferential tube 22. The combustion gas introduced into the ring-shaped conduit 10 in the outer cylinder 1 from the first hydrogen gas introduction pipe 11 flows into the outer circumferential wall space of the expansion part 8.
A part of the combustion gas introduced into the ring-shaped conduit 10 is supplied to the inner circumferential wall side of the blow-off port 7 through the section 81 , and a part of the combustion gas is introduced into the inner circumferential wall of the expansion section 8 through the bypass pipe 14 . It is configured so that it is also introduced into the bottom part 82 and also supplied to the center side of the air outlet 7.

On the other hand, the ring shape (doughnut shape) of the expansion part 8
A large number of branch pipes 9 are arranged and connected to the sealing surface 24 in a triple ring shape along the virtual concentric circle of the sealing surface 24, and the branch pipes 9 are extended to the vicinity of the opening end of the air outlet 7.

The branch pipes 9 may extend in parallel along the inner circumferential wall of the outlet 7 with a slight inclination toward the center, or at any focal point located on the extended line of the center of the outlet 5. Extend it so that it is focused at.

Now, the double pipes 3 and 4 inserted on the central axis of the outer cylinder 1 have their inlet ends connected to the oxygen gas introduction pipe 31 on the inlet end side of the outer cylinder 1, and are placed on the center line of the outer cylinder 1. An inner pipe 3 extends along the outer cylinder 1 and is connected to the internal mixing means 5 at the center of the outer cylinder 1, and an inner pipe 3 is connected to the hydrogen gas introduction pipe 41 on the inlet end side of the outer cylinder 1 and runs concentrically along the outer periphery of the inner pipe 3. The internal mixing means 5
The outer pipe 4 is connected to the mixed gas pipe line 6 which is fixed in contact with the outer pipe 4.
It consists of.

The internal mixing means 5 has a nozzle 51 having a tapered outer circumferential surface of a distal end opening of a passage whose diameter is smaller than the inner diameter of the inner tube 3, and a cylindrical mixing chamber 52 that surrounds the outer circumferential surface of the nozzle 51. The mixing chamber 52 has a guide hole 53 in its center for sucking the gas flow flowing through the outer tube 4, and its tip is tapered along the tapered surface of the nozzle 51 to serve as an outlet opening. do.

The mixed gas pipe line 6 that comes into contact with the tapered surface of the mixing chamber 52 is made of a quartz glass tube that is thicker than the above-mentioned quartz glass pipe lines, and the base end connected to the outer pipe 4 is connected to the mixing chamber 52. A mortar-shaped tapered surface 61 that can make surface contact with the tapered surface on the tip side is formed, and the diameter of the tip side of the tapered surface 61 is reduced by a predetermined section to form a constricted portion 62. After forming the enlarged diameter passage 63, the distal end thereof is gradually tapered and connected to the air outlet 7.

As a result, the velocity of the oxygen gas flow flowing inside the inner tube 3 is amplified by passing through the nozzle 51, and by injecting the oxygen gas flow from the outlet opening of the nozzle 51, the mixing chamber 52 is brought under negative pressure. , hydrogen gas flowing through the outer tube 4 enters the mixing chamber 5 through the introduction hole 53.
2 and is ejected from around the nozzle 51 while being mixed with the oxygen gas flow on the exit opening side of the nozzle 51 and led out to the constriction section 62 on the mixed gas pipe line 6 side, and then the constriction section 62 Expanded route 6
3, the mixture is further uniformly stirred, and a powerful mixed flame flow is led out from the outlet 7.

In addition, since the internal mixing means 5 is fixed in contact with the mixed gas pipe line 6 through the constriction part 62, even if a backfire occurs, it is blocked by the constriction part 62.
The inside of the internal mixing means 5 will not be ignited, so it is safe in this respect as well.

Therefore, according to this embodiment, since the bypass pipe 14 is perforated on the inlet side of the expansion section 8, a part of the combustion gas introduced into the outer cylinder 1 is transferred to the expansion section 8.
The other part is introduced into the inner peripheral wall side of the air outlet 7 along the outer peripheral surface, and the other part is introduced into the inner peripheral wall side of the air outlet 7 along the inner peripheral side of the expansion part 8 through the bypass pipe 14, resulting in a scattered arrangement. The combustion gas can be evenly distributed and ejected within the blow-off port 7 as if sandwiching the branch pipe 9 between the two sides. Moreover, even the oxygen gas led from the combustion-supporting gas pipe 2 can be expanded and agitated by the expansion part 8, and then evenly distributed within each branch pipe 9 and ejected from the outlet 7. Air outlet 7
As an extension of this, both of the gases are mixed externally, form a large-diameter flame, and can be ejected to the workpiece position while being focused. In this embodiment, since a strong mixed flame is ejected from the mixed gas pipe line 6 located on the center side of the outlet 7, the flame intensity decreases as it moves from the center side of the outlet 7 toward the periphery.
A desirable firepower distribution curve can be obtained.

Furthermore, the four oxygen and hydrogen introduction pipes 1
By adjusting the gas flow rates introduced from 1, 23, 31, and 41, the thermal power distribution curve can be adjusted freely and accurately.

On the other hand, after the prescribed heat treatment or processing is completed by the burner, the hydrogen gas introduction pipe 11 is connected to the ring-shaped conduit 10 in the outer cylinder 1, and the branch pipe 9 is connected via the combustion-supporting gas pipe 2 and the expansion part 8. By closing the connected oxygen gas introduction pipe 23, the mixed gas pipe line 6
It is possible to eject a powerful and small-diameter mixed flame stream, and using this mixed flame, it is easy to cut, for example, preforms for synthetic quartz glass production, large furnace core tubes, etc. after the processing or heat treatment is completed. You can do it.

``Effects of the Invention'' As described above, according to the present invention, a distribution means is provided at least on the inlet side of the inflated region or on the upstream side thereof, and the distribution means directly distributes the outer circumferential side and the inner circumferential side of the inflated region, respectively. Since the configuration allows combustion gas to be supplied, the combustion gas introduced into the outer cylinder can be introduced equally to the peripheral side and the center side of the outlet through the communication portion, and the outlet To smoothly form a large-diameter flame without reducing the thermal power even though large-diameter combustion gas jet ports are formed on the center side of the mouth and on the peripheral side thereof.

Further, according to the present invention, since the mixed gas pipe line for ejecting the mixed flow is inserted on the central axis within the outlet,
In addition to being able to obtain strong firepower, by adjusting the gas flow rate of the gas introduction pipe connected to these, the flame length and firepower can be freely and arbitrarily adjusted, and furthermore, the mixture ejected from the mixed gas pipe Using flame, it is possible to easily cut the workpiece after the processing or heat treatment.

It has various effects such as

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view showing an oxyhydrogen burner for processing quartz glass according to an embodiment of the present invention, and FIG.
The diagram shows each part of Figure 1 (A-A', B-B', C-C',
DD′, E-E′).

Claims (1)

[Scope of Claims] 1. The front side of a combustion-supporting gas pipe inserted into an outer cylinder whose diameter is enlarged on the outlet side and conducts combustion gas is bulged, and a large number of gases are bulged from the end side of the swollen part. In a quartz glass burner with a branch pipe extending toward the outlet side, a combustion-supporting gas pipe located on the inlet side of the expansion section or on the upstream side thereof is penetrated from the outer circumferential side to the inner circumferential side of the conduit. One or more bypass passages are provided so that the combustion gas introduced into the outer cylinder can be distributed to the outer circumferential side of the bulging part as well as to the inner circumferential side of the bulging part via the bypass passage; A mixed gas pipe containing a mixture of combustion gas and combustion-supporting gas is extended along the center axis of the outlet on the inner peripheral side of the expansion part, and a throttle passage is provided upstream of the mixed gas pipe. A quartz glass burner characterized in that it is provided with internal mixing means for mixing combustion gas and combustion-supporting gas by an aspirator action.