JPH0368726B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for sealing the ends of a bundle of capillary tubes with a sealing material made of glass, ceramics or a mixture thereof.

Relationship with prior art When manufacturing a separation membrane device in which a bundle of porous glass tubes is housed in a cylindrical container, it is necessary to create a separation membrane device in which the porous glass tubes pass through and the gaps between the porous glass tubes are filled. bulkhead is required. As a means of forming such partition walls, a method is used in which the end of a porous glass tube is placed in a mold together with powder of a sealing material, held at a predetermined sintering temperature for a predetermined time, and then cooled and released from the mold. Since the apparent volume of the sealing material is reduced, a void remains inside the partition wall, which has the disadvantage that a partition wall that is airtight against the fluid to be treated cannot be obtained.

Purpose of the Invention The present inventors have discovered a method that is effective when using glass or ceramic-based sealing materials, which have low fluidity and whose apparent volume decreases through the sealing process. The present invention was achieved through extensive research into a method for sealing thin tube bundles.

Structure of the Invention That is, the present invention provides an upper member having an opening A through which the bundle of capillaries can pass through when sealing the ends of a bundle of capillaries made of a large number of capillaries with a sealing material made of glass, ceramics, or a mixture thereof. , capable of forming an opening B into which the capillary bundle is inserted; a pressure member that can slide in a direction perpendicular to the bundle axis of the capillary bundle; an intermediate member and a lower member; and fixing the upper member, the intermediate member, and the lower member. It has an upper plate, a side plate, and a lower plate that have openings that can penetrate the thin tube bundle, and can partially concentrate stress at the engagement portion between the side plate and the upper plate and the engagement portion between the side plate and the lower plate. Using a mold loaded with a liner, the pressure member is inserted into the opening formed by the framework of the upper, middle and lower members, and the capillary bundle is inserted into the opening A of the upper member.
The sealing material is placed around the thin tube bundle, and the sealing material is heated and slid toward the thin tube bundle axis of the pressure member. The present invention relates to a method for sealing the end of a bundle of thin tubes, which is characterized in that sintering is performed by applying pressure.

Next, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a cross-sectional view of a separation membrane device in which a bundle of thin tubes made up of a large number of thin tubes is housed inside a cylindrical container, and FIG. 2 is a perspective view of an element made of the bundle of thin tubes shown in FIG. 1.

In FIG. 1, an element consisting of a capillary bundle 4 and a partition wall 5 is housed in a cylindrical container composed of a cylindrical member 1 and end plates 2 and 3, and the capillary tubes constituting the capillary bundle 4 pass through the partition wall 5. It opens on the left side. On the other hand, the other ends of the capillary tubes are all closed, and this can be done, for example, by embedding the capillary bundle in the septum without penetrating it. Alternatively, the opening may be fused by heating and melting the end of the thin tube.

The partition wall 5 is sandwiched between the cylindrical member 1 and the end plate 2. Here, 7, 8, 9, 1
0 is a gasket, and 11, 12, 13, and 14 are bolt holes. Further, 15 is a raw fluid inlet, 16 is a permeated fluid outlet, and 17 is an unpermeated fluid outlet. The raw fluid introduced from 15 flows along the outside of the capillary parallel to the tube axis toward the retentate fluid outlet 17, and the permeate fluid that has permeated the capillary wall passes through the capillary and reaches the permeate fluid outlet. The retentate exit 17 is reached. In FIG. 2, one end of the capillary bundle is shown opening through the partition wall 5, while the other end 6 is closed and embedded in the block. In addition, in FIG. 3, one end of the thin tube bundle is opened through the partition wall 5 as in FIG. 2, but the other end 6
The tube has a closed structure by heat-sealing the end of the tube.

FIG. 4 shows a partition wall 5 manufactured by the method of the present invention.
is a partial cross-sectional view of FIG. 1, showing a state in which the capillary tube 18 has passed through the sealing material 19 and is fixed with its end open.

FIG. 5 explains the method for sealing the ends of a thin tube bundle according to the present invention. Further, FIG. 6 shows a specific example of the upper member, pressure member, intermediate member, and lower member of the mold used in the end sealing method of the present invention, and FIG. 7 shows the fixed holding of the upper member, intermediate member, and lower member. FIG. 3 is a perspective view showing a specific example of a reinforcing tool that includes an upper plate, a side plate, and a lower plate. A cross-sectional view of this mold during the sealing process is shown in FIG. The mold includes an upper member 21 having an opening A27 through which the thin tube bundle 20 passes, a frame having two openings consisting of intermediate members 25, 26, and a lower member 24, and an upper plate 30, side plates 31, 32 and a lower plate 33, the upper plate 30, side plates 31, 32, and lower plate 33 are fixed using bolts and nuts so as to surround the frame. 35, 36, 37, 38 in Figure 7
is a bolt hole.

Pressure members 22 and 23 are provided that slide in close contact with the two openings.
The pressure members 22 and 23 are provided with semicircular notches so that an opening B28 can be formed into a cylindrical shape when the left and right sides meet after the sliding ends. If necessary, a thin cylinder 29 divided into two parts may be attached to the inside of the notch so as to improve mold release properties after formation.

FIG. 8 is a perspective view showing the assembled state of the mold used in the present invention, with side plates 31, 32 and upper plate 3.
A liner 3 that can partially concentrate stress is provided at the engaging portions of 0 and the engaging portions of the side plates 31 and 32 and the lower plate 33.
9, 40, 41, 42, 43 are loaded,
It absorbs the thermal stress generated in the sealed body during the cooling process after sintering the sealing material, and is effective in preventing destruction of the sealed body. The occurrence of the thermal stress is caused by the difference in coefficient of thermal expansion between the sealed body and the side and bottom plates of the reinforcing member. That is, the sealing material in the present invention is glass, ceramics, or a mixture thereof, and their coefficient of thermal expansion is often in the range of 20 to 30 × 10 ^-7 °C ^-1. For example, stainless steel alloy is used in consideration of heat resistance, but its coefficient of thermal expansion is 17×10 ^-6 °C ^-1 , which is a considerably large value compared to the sealing material. Therefore, for example
When sintering at 700°C and cooling to 20°C, if the Young's modulus of the sealed body is 7000 Kg/ ^mm2 , the stress generated in the sealed body in a mold without liner loading and no stress concentration mechanism is Since it is calculated as the product of the expansion coefficient difference, Young's modulus, and temperature difference, under the above conditions, a compressive stress of 67 to 71 Kg/ ^mm2 , which exceeds the fracture strength of the sealed body, is generated in the sealed body, and the sealed body It is estimated that the probability of damage is extremely high.

On the other hand, when the liner is loaded, even if the upper plate 30 and the lower plate 33 shrink in the A-A direction during the cooling process after sintering, the center portions of the side plates 31 and 32 do not have a liner as shown in Fig. 8. Since it has a greater degree of freedom and can be deformed outward, it relieves stress on the sealed body and is effective in preventing destruction of the sealed body. The material of the liner is not particularly limited as long as it can withstand the temperature and press pressure during sintering, but it is preferably a material that does not have unnecessarily high strength, such as carbon. This is because the compressive stress generated in the sealed body during the cooling process is extremely large and cannot be absorbed sufficiently by deformation of the side plates alone.
This is because the liner itself is compressively destroyed, thereby alleviating the stress of the sealed body and preventing the sealed body from being destroyed.

Next, the sealing process will be explained. First, the mold framed by the upper member 21, intermediate members 25, 26, and lower member 24 is fixed with a reinforcing device consisting of the upper plate 30, side plates 31, 32, and lower plate 33, and then the two horizontal openings are fixed. Then, the pressure members 22 and 23 are respectively inserted to form a chamber as shown by diagonal lines in FIG. In this case, the pressure members 22 and 23 are kept apart from each other by a suitable gap and away from the bundle axis of the capillary bundle 20, without contacting each other.Then, the capillary bundle 20 is passed into this chamber through the opening A27 of the upper member 21. It is inserted until the end reaches the surface of the lower member 24, and the other gap in this chamber is filled with the sealing material 19 through the opening A27 so that it is present around the thin tube bundle 20.
Note that there are no particular restrictions on the method of filling the sealing material, and in addition to the method described above, the upper member may be fixed after filling this chamber. Alternatively, if necessary, the slurry may be made into a slurry, filled, and then dried. Next, after heating to a predetermined temperature, the pressure members 22 and 23 are slid toward the thin tube bundle axis in the direction of the arrow shown in FIG. The volume of B28 is gradually reduced. By such pressurizing operation, the sealing material 1
The gaps 9 are eliminated and a uniform molten or sintered body is formed, and at the same time, the gaps between the thin tubes constituting the thin tube bundle 20 are also filled with the sealing material 19. In this case, if there is any excess sealing material, it will be discharged from the upper opening A27. After the pressurization and heating operation is completed, the reinforcing tool is cooled, the bolts of the reinforcing tool are removed, and each member of the mold is separated, thereby obtaining a partition wall penetrated by a bundle of thin tubes as shown in FIG. 9.

In the specific example shown in FIGS. 4 and 5, the mold has two openings perpendicular to the central axis of the opening A28, but the mold has one or more openings in the horizontal direction. A molded body can also be used.

Although the present invention has been explained above mainly using a separation membrane device as a specific example, the present invention is not limited to these applications. For example, it can also be applied to the manufacture of tube sheets in shell-and-tube heat exchangers equipped with a large number of thin tubes.

The material of the thin tube in the present invention is an inorganic material such as glass, ceramics, or metal. Although there is no particular restriction on the outer diameter of the capillary, the envelope method of the present invention is most effective when the capillary diameter is sufficiently thin, such as 2 mm or less. Although it is preferable to use porous glass as the thin tube in the present invention, a typical composition thereof is
_SiO2 22-75% by weight, _Na2O2-16 % by weight, _{Al2O3 0-5} % by weight, ZrO2 0-5 _% by weight.
Examples include high silicic acid porous glass whose raw material glass is borosilicate glass containing 5% by weight and 0 to 5% by weight of TiO ₂ . Such porous glass can be manufactured by melting and forming the above-mentioned raw material glass, then subjecting it to heat treatment at a temperature of 500 to 650°C to cause phase separation, and eluting the resulting sodium borate-rich phase with acid. I can do it. The resulting porous glass is a high silicate glass containing more than 95 weight percent _SiO2 .

The sealing material in the present invention is made of common glass, ceramics, or a mixture thereof. These materials are in a solid phase at room temperature, and at least a portion of them must melt or have sinterability at the sealing temperature, and the selection criterion is that they must have sufficient airtightness after sealing. and a small difference in coefficient of thermal expansion with the thin tube. Poor airtightness causes a decline in fluid separation performance. Furthermore, if the difference in thermal expansion coefficient is large, thermal stress will concentrate on the thin tube during the cooling process after sealing, causing breakage of the thin tube.

Therefore, it is necessary to be very careful in selecting the sealing material. For example, when sealing the above-mentioned porous glass, it is preferable to use ceramics with a negative coefficient of thermal expansion (for example, Al ₂ O ₃ , LiO ₂ , SiO (β _{- eucryptite} consisting of
A mixture with a low melting glass consisting of 18% by weight of B ₂ O ₃ and 18% by weight of K ₂ O2 provides a sealing material with a coefficient of thermal expansion approximately equal to that of the porous glass capillary.

Effects of the Invention As explained above, when using the method for sealing the end of a thin tube bundle according to the present invention, it is possible to apply sufficient press pressure when sintering the sealing material and to seal the bundle in the cooling process after sintering. It becomes possible to relieve the compressive stress generated in the body, and a sealed body with good airtightness can be obtained with a high yield. In addition, when the thin tube bundle is made of porous glass, by using a mixture of ceramics with a negative coefficient of thermal expansion and an inorganic bonding material with a softening point of 1000°C or less as the sealing material, it is possible to By reducing the difference in expansion coefficient, it is possible to prevent damage to the porous glass tube.

Examples Example 1 Composition: 62.5% by weight of SiO ₂ , 27.5% by weight of B ₂ O ₃ , 7.2% by weight of Na _{2 O} , 2.8% by weight of Al ₂ O ₃
Weight percent borosilicate glass capillary (outer diameter 2
mm, inner diameter 1 mm) is heat treated at 580℃ to separate the phases,
Next, a portion of the phase was eluted by treatment with sulfuric acid at 95°C, followed by heat treatment at 800°C to produce a porous glass tube.

On the other hand, the molar ratio of Li ₂ O ₂ , Al ₂ O ₃ and SiO ₂ is 1:
Ceramics with a negative coefficient of thermal expansion were produced by firing at 1400°C for 5 hours with a composition of 1:1.5. The average coefficient of thermal expansion of this ceramic at 300 to 600°C was -60×10 ^-7 °C ^-1 . This ceramic powder (average particle size 60 μm) and commercially available low melting glass (SiO ₂ 80 weight percent, B ₂ O ₃ 18 weight percent, K ₂ O 2 weight percent) powder (average particle size 60 μm) were mixed in a weight ratio of 35: 65 was used as a sealing material.

A mold consisting of a carbon upper member, an intermediate member, a lower member, and a liner, a stainless steel pressure member, an upper plate, a side plate, and a lower plate having the shapes shown in FIGS. 5, 6, and 7 was prepared. A bundle of 50 porous glass tubes (outer diameter 2 mm) is inserted through the opening A of the upper member until it reaches the lower member, and the mounting material is applied through the opening A into the interior of the mold. was filled. Next, the mold, the ends of the thin tube bundle, and the sealing material were heated to 700° C. and held at this temperature for 2 hours, and then a pressure member was slid to apply pressure, followed by cooling. After cooling, the mold was disassembled, and a partition wall with good airtightness and no cracks penetrated by the bundle of porous glass tubes as shown in FIG. 7 was obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a separation membrane device in which a bundle of thin tubes is housed in a cylindrical container, and FIGS. 2 and 3 are perspective views thereof. Further, FIG. 4 is a partial sectional view of a partition wall according to the method of the present invention. Furthermore, Figures 5 and 6
Figures 7 and 8 are for explaining the end sealing method of the present invention, and Figure 9 is similar to Figures 5, 6, and 8.
9 is a perspective view of a partition wall manufactured by the method of FIGS. 7 and 8. FIG. 5: Partition wall, 6: Sealed end, 19: Sealing material, 2
0: Thin tube bundle, 21: Upper member, 25, 26: Intermediate member, 24: Lower member, 30: Upper plate, 31, 3
2: Side plate, 33: Lower plate, 27: Opening A, 28:
Opening B, 38: Opening C, 39-43: Liner.

Claims (1)

[Claims] 1. The end of a tubule bundle consisting of a large number of tubules is made of glass,
When sealing with a sealing material made of ceramics or a mixture thereof, an upper member having an opening A through which the capillary bundle can pass, an opening B into which the capillary bundle can be inserted, and which is perpendicular to the bundle axis of the capillary bundle. a pressure member, an intermediate member, and a lower member that can be slid in a direction in which the upper member, the intermediate member, and the lower member are fixed; 1. A method for sealing the end of a thin tube bundle, comprising using a mold loaded with a liner capable of partially concentrating stress on the engaging portion between the upper plate and the side plate and the lower plate. 2. In claim 1, the capillary bundle is made of porous glass capillaries, and the sealing material is a mixture of ceramics with a negative coefficient of thermal expansion and an inorganic composite with a softening point of 1000°C or less, A method for sealing the end of a bundle of thin tubes having a small difference in thermal expansion coefficient from the above-mentioned porous glass.