JPS62162632A - Working of glass pipe - Google Patents

Abstract

PURPOSE:To obtain a glass pipe having prescribed outer diameter, inner diameter and cross-sectional area with simple process in high accuracy and efficiency, by simultaneously carrying out a drawing process and an expansion process under controlled condition. CONSTITUTION:A glass pipe is melted under rotation and worked to a desired size under simultaneous drawing and expanding operations in controlled manner. The above process can be carried out by heating the glass pipe while monitoring the outer diameter of the pipe with an outer diameter monitoring apparatus 8, transferring a heat-source 7 and an end of the glass pipe 1 at constant speeds v and V and, at the same time, controlling the pressure in the glass pipe 1 preferably by controlling the amount of pressurizing gas supplied from a pressurizing gas supplying tube 9. The material of starting glass tube is preferably pure quartz glass or quartz glass added with at least one kind of metal oxide.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a novel method for efficiently and precisely manufacturing a glass pipe having a desired outer diameter, inner diameter, and cross section 81) in a clean state. It is related to.

[Conventional technology]

The size of the conventional F glass pipe is l, l! ! As a means of adjusting the outer diameter of the glass pipe, the diameter expansion method is used to adjust the entire outer diameter of the glass pipe, and the cross-sectional area of the glass pipe is 1)! l! I!
There is a known stretching method for the purpose of obtaining glass pipes of the desired size by completely separating these two methods and repeating them several times.

To explain the diameter expansion method and stretching method in detail here, in both methods, first, a glass pipe as a starting material is held in a lathe, a heat source is placed around the glass pipe, and a part of the F-glass pipe is placed in the heat source. By rotating the glass pipe around its own axis while heating the glass pipe, the temperature distribution in the outer circumferential direction of the glass pipe is made uniform.

In the diameter expansion method, the pressure inside the glass pipe is increased to the pressure outside it, and the outside diameter is expanded while keeping the cross-sectional area of the heated and melted part of the glass pipe constant, and the outside diameter near the expanded diameter part is increased. By moving the heat source in a direction parallel to the axis of the glass pipe at a controlled rate while monitoring A glass pipe with a constant outer diameter and a constant cross-sectional area is obtained.

On the other hand, in the stretching method, one end of the glass pipe is moved at a controlled speed in the stretching direction, and the volume of the heated and melted portion of the glass pipe remains constant before and after this operation. As the length increases, the cross-sectional area of that portion decreases, and the outer diameter contracts due to the effect of surface tension. Then, while monitoring the vicinity of the heated and molten part, the heat source is moved at a controlled speed in a direction parallel to the axis of the glass pipe, and a continuous stretching operation is performed in the longitudinal direction of the glass pipe. The purpose is to obtain a glass pipe with a uniformly shrunk outer diameter and cross-sectional area.

[Problems that the invention attempts to solve]

However, in the conventional technology, as described above, the diameter expansion method and the stretching method are separated and repeated several times. In order to obtain the glass byte 1 having the desired size, the amount of effort and time required for caroe processing was enormous. However, there have been rare cases where glass pipes have been contaminated by the atmosphere during the process, or deformed and broken due to residual heat and their own weight. A particularly important problem is that repeated machining causes errors in each machining step to accumulate, which deteriorates the precision of the glass pipe that is the final objective.

The present invention aims at a processing method that eliminates the drawbacks of the conventional method and efficiently obtains a glass pipe of a predetermined size with a simple process and with high precision.

[Friendly means of solving problems]

In view of the problems listed above, the present invention aims to efficiently manufacture glass pipes having desired outer diameters, inner diameters, and cross-sectional areas by simultaneously carrying out the open stretching method and diameter expanding method in a controlled manner. Moreover, it is manufactured in a clean state with high precision.

That is, the present invention is a method of processing a glass pipe, in which a glass pipe is heated and melted while being rotated and processed into a predetermined size, which is characterized in that a drawing method and a diameter expanding method are carried out simultaneously while being controlled.

The material of the glass tube which is the starting material used in the present invention is particularly preferably pure quartz glass or glass in which a metal oxide of at least % Ifi is added to quartz glass, but of course other glasses may also be used. Can be used.

Particularly preferred heat sources for use in the present invention include oxyhydrogen flame, thermal plasma, and electric resistance furnaces, but are not limited to these.

In the present invention, the pressure inside the glass tube can be controlled by introducing nitrogen gas, inert gas, etc. into the glass tube to increase the pressure inside the glass tube relative to atmospheric pressure and obtain a diameter expansion effect. A similar effect can also be obtained by depressurizing the external closed space containing the material using a vacuum pump or the like.

Hereinafter, the present invention will be specifically explained with reference to the drawings.

Figure 1 is a diagram illustrating an embodiment of the present invention, in which 1 indicates a glass pipe as a starting material, and 2 indicates a glass lathe. The glass lathe 2 includes a fixed headstock 5, a chuck 4 peering into the headstock 3, a movable headstock 5, and a chuck 6 attached to the headstock 5.
Further, between the headstock 5 and the headstock 5, an oxyhydrogen burner 7 as a heat source and an outer diameter monitor device 8 for measuring the outer diameter of the glass pipe 1 are provided with a construction that can be moved between the headstock 3 and the headstock 50. It is equipped with sea urchins. Further, numeral 9 in the figure is a pressurizing gas supply pipe such as nitrogen gas or inert gas.

Connect one end of the glass pipe 1 to the pressurizing gas supply t9,
The other glass is sealed and held by chucks 4 and 6, and the chucks 4 and 6 are rotated synchronously around the axis of the glass pipe 1. At the same time, hydrogen and oxygen are introduced into the oxyhydrogen burner 7 to form an oxyhydrogen flame, which partially heats the glass pipe 1.

The chuck 6 and the oxyhydrogen burner 7 are moved at preset speeds V and V in the directions shown by the arrows in FIG. 1, respectively. This operation provides a stretching effect. Further, the outer diameter monitoring device 8 is also moved in synchronization with the oxyhydrogen burner 7 to continuously measure the outer diameter of the glass pipe 1. The output signal of the outer diameter monitor device 8 is transmitted to an outer diameter control device (not shown).
The amount of pressurizing gas, such as nitrogen gas, introduced into the glass pipe 1 via the pressurizing scum supply pipe 9 is controlled so as to minimize the tolerance with the input and preset outer diameter, The internal pressure of glass pipe 1 is l! 1) 1I and F obtain extremely high-precision diameter expansion effects.

V and V, which should be carefully set in performing these series of operations, are determined in the following manner. First, the cross-sectional area of the glass pipe 1 made of starting materials is 80. If the length is t-L and the cross-sectional area of the glass pipe after processing is 81, then the following relationship (1) (%) holds true. Therefore, the following formula (2) s, /s1
= (1+v/V) -so (21 and 7!, Bo/B, the ratio of V and V is determined.

Next, regarding the values of V and V, consider the cross-sectional area and material of the glass pipe 1, the ability of the oxyhydrogen flame, etc., and set the value within a range that does not apply excessive tension to the glass pipe 1 and allows the outer diameter to be controlled. selected from. Generally, the larger V and V are, the greater the tension applied to the glass pipe 1 is, and the smaller v and V are, the lower the viscosity of the glass pipe is, making it difficult to control the outer diameter. Table 1 below shows an example of these V and the optimum conditions for V, which were obtained as a result of intensive studies by the present inventors. In this way, a glass pipe having the desired outer diameter, inner diameter, and cross section of 8tt is obtained.

Table 1 An example of optimal conditions for v and V (starting material: gas: 18
t/min] FIG. 2 is a diagram showing another embodiment of the present invention. In the figure, 1 indicates a glass pipe as a starting material, and 10 indicates a frame. The mount 10 includes movable headstocks 1) and 12 and chucks 4 and 6 attached to these headstocks,
Between the headstock 1) and 12, there is an electric resistance furnace 13 that is a heat source and an outer diameter monitor device 8't that measures the outer diameter of the glass pipe 1.
- It is fixed. Further, numeral 9 in the figure is a pressurizing gas supply pipe such as nitrogen gas or inert gas. glass pipe 1
One end is connected to the pressurizing gas supply pipe 9, the other end is completely sealed and held concentrically with the electric resistance furnace 13 by the chucks 4 and 6, and the glass pipe 1) is partially heated by the electric resistance furnace 13. . The chucks 4 and 6 are moved in the direction shown by the arrow in Fig. 2 at preset speeds #V and v (V (v) to obtain the F stretching effect. In this case, V and M are expressed by the following formula ( 3) and Fig. 1 are determined from the same optimum conditions.

so7'sl=v/7"" (3) However, So: cross-sectional area of the starting material pipe S1: cross-sectional area of the pipe after processing. A glass pipe having an outer diameter, an inner diameter, and a cross section of 8t can be obtained.

Further, even if thermal plasma is used as the heat source instead of the electric resistance furnace 13 in FIG. 2, a glass pipe of a desired size can be obtained by performing the same operation.

〔Example〕

Example 1 According to the structure and method shown in FIG. 1, a glass pipe 1 was prepared with an outer diameter, an inner diameter, and a cross-sectional area of 259 m, respectively.
9 tram, 224.5 wm"C; h Le MJ Iki! Combined H quartz tube was used. During processing, the flow rate of Kusui gas and oxygen gas were each 55 t /
min and 18 t/min. Furthermore, the moving speeds V and V of the chuck 6 and the oxyhydrogen burner 7 are 45.01) m7 min and 59.5 wa/min, respectively. As a result, the outer diameter, inner diameter, and cross-sectional area of the glass pipe obtained after processing were 27.
0m, 25.8mm, 127, 7wm", we achieved the desired outer diameter and cross-sectional area with very good accuracy that matches the design value. In addition, the longitudinal outer diameter variation of the glass pipe after processing was within ±15 mm. The time required for this processing was approximately 30 minutes, including the time for preparation work, which was less than half the time required to obtain such a glass pipe using the conventional method. .

Example 2 Similar to Example 1, a quartz glass pipe was processed using the configuration and method shown in Figure 1. Fluorine t- as the starting material glass pipe 1
A synthetic quartz tube containing t5 weight percent was used, and the outer diameter, inner diameter, and cross-sectional area of the quartz tube were 25.01 m and 15.0 m, respectively.
．． The flow rate of hydrogen gas and oxygen gas introduced into the oxyhydrogen burner 7 during processing was 514.2 m'' on day 0.
t/min.

It was 20t/min. Further, the transfer speeds V and V of the chuck 6 and the oxyhydrogen burner 7 are each 45. gourd/min, 26.8
It was days/minutes.

As a result, the outer diameter, inner diameter, and cross-sectional area of the glass pipe obtained after processing were 5 IIOarm, 27.4 m, and 1, respectively.
) With 7.2 and 8, the outer diameter and inner diameter matched the design values, and the cross-sectional area was -cL1 m'', achieving the desired outer diameter, inner diameter, and cross-sectional area with extremely high machining accuracy. The variation in the outer diameter of the glass pipe in the longitudinal direction was within a range of ±0.2.

Example 3 A glass pipe was processed according to the vI7K method shown in FIG. As a starting material glass pipe, the outer diameter, inner diameter, and cross-sectional area are 510 m, 21.0 m, and 50 m, respectively.
A 9S+" synthetic quartz tube was used. The temperature inside the electric resistance furnace during processing was measured using a thermocouple and the temperature was 1850℃ at 9.
Met. The moving speeds V and V of the chucks 4 and 6 are 22. Ovm 7 minutes, and 6a 5.7 minutes.

The outer diameter, inner diameter, and cross-sectional area of the resulting glass pipe were 2aO, 240, and 1654, respectively, and the desired outer diameter and cross-sectional area were achieved with very good accuracy, which matched the design values. Furthermore, when the OH group content of the obtained glass pipe was measured by infrared spectroscopy, it was found to be a glass pipe with a very low OH content, below the detection limit (100 ppm).

Example 4 In this Example 4, the frame was made horizontal with the configuration shown in Fig. 2, and the structure was made horizontal by the same operation as in Example 3, except that thermal plasma was used instead of a 13K electric resistance furnace as the heat source. The retained synthetic quartz pipe was processed. The outer diameter, inner diameter, and cross-sectional area of the quartz pipe are 2 &Osm and 1 aom, respectively.
, 276.5 s+". Also, the moving speeds of the chucks at both ends, V and vVi, were each 34.0 mIl+/min and 66.9 tm/min. As a result, the outer diameter of the glass pipe was 9. , inner diameter and cross-sectional area are respectively 2 & O
ws, 24.6 m, 14α5 m", the desired outer diameter and cross section of 8F were achieved with very high machining accuracy that matched the design values. In addition, the obtained nine-kilogram tube had a very high OH as in Example 3. It was rare because the content was low.

As described above, by using an electric resistance furnace or heat plus -r (i = i) as a heat source, a glass pipe with extremely low OH content can be obtained. The chuck that holds both ends of the is moved, but this is done by fixing the chuck on one side in the same manner as in Example 1.
It goes without saying that the same effect can be obtained by moving the other chuck and heat source.

In addition, in the above-mentioned Examples 1 to 4, the flow rate of the pressurizing nitrogen gas introduced into the glass pipe was α6 to 2.0.
It is controlled within a range of 27 minutes.

Comparative Example 1 In Comparative Example 1, when processing a pure synthetic quartz pipe, the stretching process and the diameter expanding process were carried out separately. The mechanical equipment used was roughly the same as that shown in Figure 1, but
In both processes, the outer diameter control device controls the moving speed of the hydrogen phosphate burner 7 and the chuck 6, and in the diameter expansion process, the flow rate of nitrogen gas introduced into the inside of the glass pipe 1 is kept constant. Nine. First, a quartz glass pipe was processed by a stretching method to obtain the desired cross-sectional area. To explain the operation of this stretching method in detail, in FIG.
The glass pipe 1 is partially heated and melted by the oxyhydrogen flame formed by the hydrogen gas and oxygen gas introduced into the oxyhydrogen burner 7 while rotating around the axis of the glass pipe 1. Then, while monitoring the outer diameter near the heated and melted portion of the glass pipe 1 with the outer diameter measuring device 8, control is performed so that the tolerance between the preset outer diameter and the measured outer diameter of the glass pipe 1 is minimized. The oxyhydrogen burner 7 and the chuck 6 are moved in the direction of the arrow shown in FIG. 1 at a specific speed. In this way, the outer diameter of the glass pipe 1 is controlled over its entire length, and the machined cross-sectional area is adjusted. Next, the outer diameter of the glass pipe 1 was adjusted using the diameter expansion method.

In the diameter expansion method, operations are roughly the same as in the stretching method, but the position of the chuck 6 and the flow rate of nitrogen gas introduced into the glass pipe 1 are kept constant, and only the moving speed of the oxyhydrogen burner 7 is monitored. Control was carried out to minimize the tolerance between the outer diameter of the glass pipe 1 and the outer diameter set by the crimping process.

By this simple operation, the outer diameter of the glass pipe 1 is adjusted to v! over the entire length. I made 4 adjustments. The initial outer diameter, inner diameter, and cross-sectional area of the quartz glass pipe used for this series of processing were 2αOx.

1 (10m1), 255. ．． 6- Ivy. Extension work s-
The flow rates of hydrogen gas and oxygen gas introduced into the "ca" hydrogen burner 7 were 60 t/min and 184/min, respectively.

The outer diameter, inner diameter, and cross-sectional area of the quartz glass pipe after stretching are 15.2 m and 7.6 cages, respectively.

I failed at 156.1-. At this time, the variation in the outer diameter of the quartz glass pipe in the longitudinal direction was within a range of ±12 m. In the diameter expansion process, the flow rates of hydrogen gas and oxygen gas introduced into the oxyhydrogen burner 7 were 50 t/min and 18 t/min, respectively, and the outer diameter, inner diameter, and cross-sectional area of the glass pipe after processing were 27.
0m.

216m, 155.6wx”C height.The outer diameter variation in the longitudinal direction of the quartz glass pipe near the top was ±α7■, which was a slightly large variation range.The time required for these series of processing was the preparation work time. Including that, it took about 1:15.

[Effects of the Invention] As described above, when processing a glass pipe, the drawing process and the diameter expanding process are carried out simultaneously while controlling the pressure inside the glass pipe. F,
It becomes possible to obtain glass pipes with high precision in an efficient and short time.9.

[Brief explanation of drawings]

An example using a heat source and a fixed headstock, and FIG. 2 shows an example using an electric resistance furnace heat source and a movable headstock.

Claims (7)

[Claims] (1) A method for processing a glass pipe, which involves heating and melting a glass pipe while rotating it and processing it into a predetermined size, which is characterized in that a stretching method and a diameter expanding method are carried out simultaneously while being controlled. (2) Move the heating, heat source and one end of the glass pipe at a constant speed while monitoring the outer diameter of the glass pipe, and at the same time control the pressure inside the glass pipe, thereby adjusting the outer diameter and cutting edge of the glass pipe. A method for processing a glass pipe according to claim (1), wherein the area is a predetermined size. (3) While monitoring the outside diameter of the glass pipe, both ends of the glass pipe are moved at a constant speed, and at the same time, the pressure inside the glass pipe is controlled, thereby adjusting the outside diameter and cross-sectional area of the glass pipe to a predetermined value. A method for processing a glass pipe according to claim (1), wherein the size of the glass pipe is determined. (4) A method for processing a glass pipe according to any one of claims (1) to (3), wherein the glass pipe is made of pure silica glass. (5) Processing of the glass pipe according to any one of claims (1) to (3), wherein the glass pipe is made of quartz glass added with at least one metal oxide. Method. (6) The method for processing a glass pipe according to any one of claims (1) to (3), wherein the glass pipe is made of fluorine-doped quartz glass. (7) A method for processing a glass pipe according to any one of claims (1) to (3), in which heating is performed using an oxyhydrogen flame, an electric resistance furnace, or thermal plasma.