JPS6024062B2 - Flange sealed quartz tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a flange-sealed quartz tube that enables direct welding and sealing to a metal container, etc., in which a metal flange is hermetically sealed at a predetermined position of a quartz tube or solid quartz tube. It is related to pipes.

Conventionally, quartz tubes have been used to protect thermocouples used to measure temperatures inside high-temperature containers, but when measuring temperatures inside high-temperature, high-pressure containers, airtightness at the part where the quartz tube is inserted into the high-temperature, high-pressure container is an issue. becomes.

It is impossible to shield the insertion portion with resin or the like because of burnout caused by heat.

Furthermore, fireproof cement or the like may crack or peel due to the heat cycle of the container, making it difficult to provide a complete shield.

In addition, recently, optical fibers used for information transmission have adopted a two-layer structure consisting of a core with a high refractive index and a cladding with a lower refractive index in order to confine and propagate light. Multi-mode optical fibers include step-type optical fibers that propagate while repeating total internal reflection, graded-type optical fibers that propagate while changing the path continuously according to the refractive index distribution in the ridge direction, and multi-mode optical fibers with a small core diameter to reduce the propagating mode. There are single-mode optical fibers that allow only a single mode to propagate, but low-loss silica glass is mainly used in these fibers.

However, when using a quartz-based optical fiber, for example, when extracting information inside a sealed high-temperature, high-pressure container, there is a problem in maintaining the airtightness of the penetrating portion of the wall of the sealed high-temperature, high-pressure container.

Due to the high temperature, it is impossible to shield with resin, and even with shields using inorganic shielding agents, it is difficult for the shield to withstand heat cycles.

In addition, when a particularly high degree of airtightness is required, such as space-related equipment or nuclear power-related equipment, the resin itself has an airtightness limit for resin shields, and if a certain airtight differential pressure is exceeded,
It is impossible to maintain airtightness. Therefore, under high-temperature, high-pressure conditions or when particularly high airtightness is required, metal flanges are melt-sealed to quartz tubes used for thermocouple protection tubes, optical fibers, and solid quartz tubes. However, if this metal flange is welded to a high-temperature, high-pressure container, an airtight container, etc. by silver brazing or the like, airtightness that satisfies high-temperature, high-pressure or ultra-high airtightness conditions can be imparted. However, in this case, it has been difficult to weld and seal a metal flange, such as Kovar, to a quartz tube because of the large difference in coefficient of thermal expansion between the two. In other words, the hot-blood tension coefficient of quartz glass is 5 x 10-7/°C.
On the other hand, Kovar (Fe-Nj-Co) has a thermal expansion coefficient of 45 to 51×1, which is widely used as an airtight seal for glass.
0-7/℃, and the thermal expansion coefficient of the shelf silicate glass sealed to this is 38 to 53 x 10-7/℃, and the difference in thermal expansion coefficient between the two is small and there is no problem, but quartz glass has a thermal expansion coefficient of 38 to 53 x 10-7/℃. Because the difference in expansion coefficient is too large, cracks may occur during melt-sealing, making it difficult to melt-seal, for example, a Kovar metal flange to quartz.
It has been difficult to weld and seal a quartz tube through a metal container in a heat-resistant and airtight manner.

The present invention has made it possible to fuse and seal metal flanges to fused quartz glass, which was considered difficult. A sealed glass cut tube 3 made of shelf silicate glass or the like is melt-sealed to the narrow tube side of a metal flange tube 2 for glass sealing with one side narrowed.
A plurality of glass cut tubes 4 having a constant length each having a different coefficient of thermal expansion are interposed between the two tubes and the quartz tube 1 to sequentially reduce the gradient of the coefficient of thermal expansion between the two tubes. The fused quartz tube sealing flange portion A is melt-sealed at a predetermined position outside of the quartz tube B using the end 6 of the quartz tube 1 so that the quartz tube B is located in the center. This is a flange-sealed quartz tube with an integrated structure.

In addition, a plurality of glass cutting tubes 4a, 4b...4n
are the quartz cut tube 1 (thermal expansion coefficient 5 × 10-7/℃) and the sealed glass cut tube 3 (for example, the thermal expansion coefficient unevenness of shelf cirate glass ~ 5
In order to alleviate the gradient of the thermal expansion coefficient between 3xlo-7°C), for example, the glass cutting tube 4a has a thermal expansion coefficient of 10x10-7°C.

〇 4b is 17 x 10-7. 〇・・・--・4n is 3
Cut glass tubes of a certain length, each having a different coefficient of thermal expansion, are melt-sealed one after another so that the coefficient of thermal expansion between the two changes in stages, such as 5 x 10-'/℃. This is what I wore. Further, glasses having predetermined coefficients of thermal expansion different from 4a, 4b, . . . 4n can be made by suitably blending glass materials having different coefficients of thermal expansion. In addition, quartz tube 1
The end portion 6 of the quartz tube B is melt-sealed to the quartz tube B by holding the space between the quartz cut tube sealing flange portion A and the quartz tube B with a spacer or the like.
The end portion 6 of the quartz cut tube 1 may be heated and welded with a burner.

As shown in FIG. 3, a heat-resistant inorganic buffer material 7, for example, a ceramic fiber material, is applied in advance to the gap between the quartz tube B and the quartz tube 1 and glass tube 4 portion of the quartz tube sealing flange portion A. If a bulk, vapor, plunket, or felt material is interposed, the quartz can be removed with a smoother or the like when the end 6 of the cut quartz tube 1 is melt-sealed to the quartz tube B. There is no need to hold the sealing flange part A of the teaching tube, and since the quartz tube sealing flange part A is held with the heat-resistant inorganic buffer material 7 during use, it is strong and the sealed end The impact applied to the portion 6 can be alleviated.

Next, quartz tube B can be used as a hollow tube used for protection tubes such as thermocouples, a solid tube consisting of a core part and a cladding part used for optical fibers, or ordinary quartz birch. It can be used by sealing the cut tube or by melting and sealing the flange portion A.

To use the flange-sealed quartz tube of the present invention, the flange-sealed quartz tube of the present invention is inserted into the insertion hole of a high-temperature, high-pressure container or a container that requires high airtightness, and the flange-sealed quartz tube of the present invention is inserted into the metal flange tube 2 for glass sealing. The metal container may be silver-brazed or soldered.

As stated above, the flange-sealed quartz tube of the present invention has high airtightness and low leakage because each joint is sealed with glass or with a metal and a glass. , 1 x 10-2 Tor with mass spectrometer type helium leak detection
r'-1/s or less, and can be used in ultra-airtight containers, high-temperature, high-pressure containers, etc.

Furthermore, a glass cut tube 4 having a fixed length having different thermal expansion and cough coefficients is interposed between the quartz tube B and the metal flange tube 2 for sealing the glass to gradually reduce the gradient of the thermal expansion coefficient. Because of this, it can withstand heat cycles well, etc.
It has many features and has made it possible to weld and seal a metal flange to a quartz tube, which was previously considered difficult. Furthermore, the flange-sealed quartz tube of the present invention has
Metal containers are usually soldered with silver so that they can be used under high-temperature airtight conditions, but in this case, the metal flange tube 2 for glass sealing becomes quite high temperature and is also subject to the thermal stress of the metal container, but the thermal expansion coefficient of Kovar etc. The metal flange tube 2 is made of metal whose thermal expansion coefficient is close to that of glass and is made in two thin layers to minimize the effect of heat on the glass cutting tube 4, and the glass tube of a certain length has a plurality of sequentially different thermal expansion coefficients. The glass cut tube 4 and the quartz cut tube 1 have a structure that successively reduces thermal stress, so the metal flange tube 2 can be brazed to a metal container without causing thermal abnormalities in each part. In addition, the thermal stress from the metal container during use is relieved one after another in the metal flange tube 2, the glass teaching tube 4, and the cut quartz tube 1, without causing any abnormality in each part. The end portion 6 is melt-sealed in a small area to the quartz tube B.
Since the influence of thermal stress and melting strain on the quartz tube B during welding and use is reduced, even if the quartz tube B is an optical fiber, its function will not be impaired. It has many features, such as enabling the tube B to be soldered and sealed to a metal container and to be used in a high-temperature environment.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view of a flange portion of the present invention, and FIGS. 2 and 3 are explanatory cross-sectional views of a flange-sealed quartz tube of the present invention. 1 is a quartz cut pipe, 2 is a metal flange pipe for glass sealing, 3
4 is a sealed glass tube, 4 is a plurality of glass tubes having different coefficients of thermal expansion, 4a, 4b...4n are each of the glass tubes, and 5 is a quartz tube B and a quartz tube. The gap between the sealing flange part A and 6 is the end of the quartz tube, 7 is the heat-resistant inorganic buffer material, A is the quartz tube sealing flange part, and B is the quartz tube. 1st
Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. Between a sealed glass tube and a quartz tube that are sealed on the thin tube side of a metal flange tube for glass sealing, one of which is thin,
A quartz cut tube sealing flange made by welding together a plurality of glass cut tubes each having a different coefficient of thermal expansion to sequentially reduce the gradient of the thermal expansion coefficient between the two cut tubes, is attached to a quartz tube or a solid quartz tube. A quartz tube or a solid quartz tube or a solid quartz tube is placed at a predetermined position on the outside, and the end of the cut quartz tube is integrated with the end of the quartz tube to allow direct welding to the metal container. A flange-sealed quartz tube characterized by: 2. Between the sealed glass cut tube and the quartz cut tube that are sealed on the thin tube side of the metal flange tube for glass sealing with one side narrowed,
A quartz cut tube sealing flange made by welding together a plurality of glass cut tubes each having a different coefficient of thermal expansion to sequentially reduce the gradient of the thermal expansion coefficient between the two cut tubes, is attached to a quartz tube or a solid quartz tube. A heat-resistant inorganic buffer material is interposed in the cut glass tube part so that the quartz tube or solid quartz tube is located at the center of the tube, and the ends of the cut quartz tube are integrated by welding. A flange-sealed quartz tube characterized in that it can be directly melt-sealed to a metal container.