JPS5914678B2 - Manufacturing method of insulation pipe joints - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is applicable to a central part of a pipe which is installed, for example, by penetrating the wall of a metal airtight container, or which is used to maintain electrical insulation by being interposed between metal pipes. The present invention relates to a manufacturing method for an insulated pipe joint having a through hole.

Note that in this invention, insulation means electrical insulation. The insulated pipe joint according to the present invention, that is, the electrically insulated pipe joint is:
For example, it is suitable for use in cooling devices that use low-temperature liquids such as liquid nitrogen or liquid helium, and for distributing liquids or gases at temperatures higher than room temperature (100°C to 200°C) while maintaining insulation. It is something. used for the above purposes
The following are the main characteristics required for insulated pipe joints used in this industry. It has good airtightness, has excellent resistance to cold and thermal shocks and does not deteriorate due to repeated rapid rises and falls in temperature, has high mechanical impact strength, and has no unevenness on the inner diameter of the tube and has low flow resistance. These characteristics include low performance, no deterioration over time, and long-term reliability.

In addition, for practical use, it must be easy to attach to the vessel wall or connect to a metal pipe, have an outer diameter of 100 mm for a constant flow rate, have a suitable shape5, and be easy to manufacture. There is an urgent need for it to be easy and inexpensive.
In the case of this type of insulated pipe joint, the basic structure is a structure in which an insulator is interposed between two conduits.

In this case, it is the insulator that has the greatest control over the characteristics.
This insulator will be explained below. When organic materials are used as insulators, there is a fatal flaw in that airtightness deteriorates due to changes in the properties of the material itself over time when the temperature rises or the temperature rises and falls repeatedly. Therefore, it cannot be used in reality. Next, if vitreous material is used, cracks may occur due to sudden changes in temperature, or there may be defects such as low mechanical impact strength. As in the case of , they also have a fatal flaw of low thermal and mechanical impact strength, which also makes them unusable in reality. Insulators made of glass and microplastics, which will be described in detail below, are the most excellent in terms of the above-mentioned properties. Glass and mica plastic bodies are made from a mixture of vitreous powder and mica powder, heated to a temperature at which the vitreous material softens and flows under pressure, and then press-molded in the heated state. It is an insulator obtained by

The most ideal insulated pipe joint using glass or mica plastic as an insulator was previously proposed by the present inventors (Japanese Patent Application No. 1983-
51151).

The structure will be explained below with reference to FIG. FIG. 1 is a joint cross-sectional view showing the structure. In FIG. 1, 1 is a first tubular member having a cylindrical body 1-1, 2 is a concave second tubular member, The cylindrical body 1-1 of the first tubular member 1 is connected to one end of the cylindrical body 2-3, which has the same inner and outer diameters as the inner and outer diameters of the cylindrical body 1-1 of the first tubular member 1, via the shoulder 2-1. It is provided with an outer peripheral fitting 2-2 having an inner diameter larger than an outer diameter.

All of them are made of metal that can withstand heating at about 600°C, and iron, stainless steel, and the like are preferably used. The first hexagram and the second tubular members 1 and 2 are supported by holding spaces 3 and 3-1, and the spaces 3 and 3-1 are filled with an insulator 4 made of glass and mica plastic. The first tubular member 1 and the second tubular member 2 are completely sealed and fixed, and insulation is maintained. 1a and 2a are connected to the vessel wall or metal pipe by an appropriate method such as welding or screwing.

This insulated pipe joint completely maintains the required basic properties such as airtightness, thermal and mechanical impact strength, and reliability against aging. If the inner diameter of 2 is as thin as 1 inch (2.54 cm), manufacturing is relatively easy, but if the inner diameter is large, for example 8 inches (7.62 cm) or 10
inch (25.4 (-m)), it is also related to molding equipment, and manufacturing is extremely difficult. Even if equipment that meets the necessary conditions is installed, the manufacturing process will be complicated and the manufacturing price will be high. However, this invention provides a method that allows even large-sized products to be manufactured easily.

Prior to explaining the contents, a conventional manufacturing method for small-sized products will be explained with reference to FIG. Figure 2 is a longitudinal cross-sectional view showing the state of molding for a conventional small-shaped product, and Figure 2a (
Figure 2 b1 (right half) shows the state immediately before pressure molding (left half)
This figure shows the state after pressure molding is completed.

Figure 2 shows 1, 1-1, 2, 2-1, 2-2, 2-
3, 3, 3-1 and 4 are the same parts as in FIG. 1
-2 is a support portion provided at the bottom of the first tubular member.

Reference numeral 5 denotes a wall portion of the divided structure, 6 a frame, and 7 a holding stand, which is located in the central through hole of the second tubular member and supports the support portion 1-2 of the first tubular member 1. The space 3-1 of the second tubular member 2 and the first tubular member 1 has a structure that maintains a conical shape.

A support 8 is located between the wall 5 and the second tubular member 2 and supports the shoulder 2-1 of the second tubular member 2.

Reference numeral 9 is made of pressurized metal so as to fit into the wall portion 5 and the first tubular member 1.

Reference numeral 10 denotes a presser metal, which is located above the first tubular member 1 and functions to pressurize the first tubular member 1 by receiving the pressing force of the drive unit 11.

The wall portion 5, frame 6, and support base 8 constitute an external mold, and the holding base 7 constitutes an internal mold. The molds 5, 6, 7, 8 and the pusher 10, which are composed of the above five parts, are used.

Reference numeral 12 denotes a preformed body, which is made by adding water to a mixed powder of vitreous powder, which is the raw material for the insulator 4, and mica powder to make it wet.
It is molded in advance into a cylindrical product with a through hole in the center using another mold (not shown) and dried to remove moisture. , the holding table 7 and the support table 8 are assembled, and the pressurizing metal 9 is not assembled.
and heat to a predetermined temperature.

The presser metal 10 is not heated. The first tubular member 1, the second tubular member 2, and the preformed body 12 are each heated to a predetermined temperature. When heating is completed, the second tubular member 2 is first inserted into the space between the holding table 7 and the supporting table 8. Next, the first tubular member 1 is placed on the support base 7. Next, the pusher 10 is placed on the first tubular member 1, and finally the preform 12 is placed on the second tubular member 2. The state at this time is shown in FIG. 2a. When the insertion is completed, the pressurized metal 9 is attached to the preformed body 1.
2, pressure is applied to the pusher metal 10 by the drive unit 11, and then the presser metal 9 is pressurized using a pressure molding machine. The preform 12 flows and fills the voids 3 and 3-1, and forms the insulating part 4. The state at this time is shown in FIG. 2b. When the preform 12 flows, a floating pressure shown by an arrow 13 is generated on the bottom surface of the first tubular member 1, and a phenomenon in which the first tubular member 1 floats occurs. In order to prevent this floating, it is necessary to apply a pressure greater than the floating pressure to the presser bar 10 prior to pressurizing the presser bar 9 to prevent floating.
When the pressure molding process is completed, the molded product is cooled to a predetermined temperature, the mold is disassembled, and the molded product is taken out. The molded product is made into the product shown in FIG. 1 by removing the deleted portion 14 shown by the vertical chain line in FIG. 2b by machining. However, when the inner diameter of the tubular members 1 and 2 is small (about 1 inch), the above-mentioned conventional method can be applied very effectively, but as the inner diameter becomes thicker, the specific application becomes difficult. It becomes difficult. The second reason will be explained below. Generally, when molding a glass or mica molded body, a pressing force of 1/2t0n/Cd is required during carving. Specifically, in FIG. 2, when the total pressure on the preform 12 is set to 400 ton, the floating blade indicated by the arrow 13 reaches 200 to 250 ton. In order to satisfy the above conditions, the pressure molding machine is equipped with a main drive section (not shown) having a capacity of 400 tons for pressurizing the pressure metal 9. Oshikin 10
It is necessary to have a sub-drive section 11 with a capacity of 250t0n for pressurizing. When an independent sub-drive section is provided inside the main drive section as described above, the capacity of the sub-drive section is generally limited to 80% of the capacity of the main drive section. Therefore, if the capacity of the sub-drive section is set to 250ta1, the capacity of the main drive section will inevitably be about 800t0n. In this way, the pressure molding machine used as molding equipment becomes huge, which inevitably causes the product price to rise.As the size of the paper and equipment increases, the molding operation becomes difficult and stable molding becomes difficult.
A fatal flaw is that many problems occur on the manufacturing side, making production impossible in reality. The inventor is
Using a special, large-capacity pressure molding machine, large-sized products that fully retain the excellent characteristics of small-sized insulated pipe fittings using glass and mica plastic as an insulator and sealant are used. After conducting as much research as possible to find an insulated pipe joint that could be manufactured at low cost, we succeeded in obtaining a satisfactory product. An embodiment of the method for manufacturing an insulated pipe joint according to the present invention will be described with reference to FIGS. 3 and 4. FIG.

FIG. 3a is a vertical cross-sectional view showing a state in which molding has been completed, and FIG. 3 is a vertical cross-sectional view showing the structure of a product that has undergone bilt machining.

Prior to detailed explanation, the manufacturing method will be explained with reference to FIG. The mold used is composed of five parts: a wall portion 5, a frame 6, an external mold for a support base 8, an internal mold for a holding base 7, and a pressurizing metal 9. The holding stand 7 is a wall tube 1-4 of the first tubular member 1.
It is structured to place and hold. Second tubular member 2
A similar product to the conventional product shown in FIG. 2 is used for this purpose. 1st
For the tubular member 1, a tubular member 1-1 having the same inner and outer diameters as the inner and outer diameters of the tubular member 2-3 of the second tubular member is used. - Wall tube 1 that fits with the inner diameter of 3
-4, and a ring-shaped flange 1-3 whose outer diameter is smaller than the outer diameter of the outer peripheral fitting 2 is used in the middle part of the cylindrical body 1-1. The molding is the same as the conventional method explained in Fig. 2.
The forming molds 5, 6, 7, 8, the pressurizing metal 9, the first and second tubular members 1, 2, and the preform 12 are heated to a predetermined temperature, and the second The tubular member 2 is inserted between the outer mold and the inner mold, placed on the support 8, and the wall tubes 1-4 of the first tubular member 1 are inserted into the second tubular member 2.
It is inserted into the cylindrical body 2-3 and placed on the holding stand 7, and is inserted so that there is a gap between the lower surface of the flange 1-3 and the upper surface of the outer peripheral fitting 2-2, and the preforming is performed. The body 12 is placed on the outer peripheral fitting 2-2.

This situation is shown in Figure 4a. Next, pressurize gold 91fC
The preformed body 12 is pressurized and press-fitted into the spaces 3, 3-1 formed by the first hexagram and the second tubular members 1, 2 to form the insulator 4. The state at this time is shown in FIG. 4b. In the case of the above manufacturing method, since the insulator is press-fitted into the lower surface of the first tubular member 1, the first tubular member 1 naturally floats for the same reason as explained in FIG. Pressure is generated, but the flanges 1-3 receive downward pressure through the preformed body 12, which cancels out the levitation pressure, so the levitation of the first tubular member 1 is eventually completed. is prevented.

Therefore, unlike conventional manufacturing methods, it is not necessary to apply pressure to the first tubular member 1 to prevent floating prior to applying pressure to the preform 12. The molded product is machined into a product having the shape shown in Figure 3b. In the case of this shape, the flange portion 1-3 remains inside the insulator 4, but it is a matter of course that a structural product can be manufactured from which this portion is removed.
However, when this manufacturing method is used, a flange 1-3 having strength to withstand the pressure of the pressurizing metal 9 is provided on the outer circumference of the first tubular member.
It is necessary to provide Next, another embodiment will be explained as shown in FIGS. 5 and 6.

FIG. 5a is a longitudinal cross-sectional view showing the structure after molding, and FIG. 5b is a longitudinal sectional view showing the structure of the product after machining. Prior to detailed explanation, the manufacturing method will be explained with reference to FIG. The mold used is made up of five parts, 5, 6, 7, 8, and 9, as shown in Fig. 4. Second tubular member 2
A similar product to the conventional product shown in FIG. 2 is used. The first tubular member 1 has the same wall tube 1-4 as that in FIG. 4, but does not have the flange 1-3.
A jig 18 for forming a triangle is used. The molding jig 18 has an outer diameter equal to or smaller than the inner diameter of the first tubular member, and has a base metal 18-1 at the bottom that can be placed on the top surface of the first tubular member. That's fine. Pressurized metal 9
The outer diameter of the molding jig 18 is adapted to fit with the outer periphery of the molding jig 18. The molding is performed by heating the inner and outer molds, the pressurizing metal, the first and second tubular members 1, 2}, and the preform 12 to predetermined temperatures, in the same manner as described with reference to FIG. The molding jig 18 is heated to the same temperature as the tubular members 1 and 2.
As shown in FIG. 6a, the first and second tubular members 1 and 2 are arranged in the same manner as in FIG. 12 is placed on the second tubular member as a shaped product that can fill the space formed between the first tubular member 1 hexagram and the wall portion 5 with a small gap. .

This state is shown in Figure 6a. Next, the preformed body 12 is pressurized by the pressurizing metal 9, and the first and second tubular members 1 are
, 2, between the first tubular member 1 and the wall portion 5, and between the pressurizing metal 9 and the base metal 18-1.

In this manufacturing method, since the first tubular member 1 itself receives pressing force via the base metal 18-1, floating pressure is no longer generated. There is no need to apply pressure to the tubular member 1 to prevent it from floating. The molded product is machined into a product having the shape shown in FIG. 5b of V1. As is clear from the description of the above embodiments, if the manufacturing method according to the present invention is followed, the phenomenon that the first tubular member 1 floats when the raw material to be an insulator is injected under pressure disappears. Unlike the manufacturing method, it is no longer necessary to apply pressure to the first tubular member 1 to prevent floating before pressurizing the raw material that will become the insulating snout, so even if the product shape becomes large, a special mechanism is not required. It is possible to manufacture the product easily and inexpensively using a general pressure molding machine without using a pressure molding machine having a pressure molding machine. Although the gist of the present invention is clear from the above description, in order to facilitate understanding, the relationship between the pressure molding pressure and the floating pressure of the first tubular member 1 will be specifically explained together with the molding conditions.

First, the preformed body 12 is created, and the glass material is Pb.
O: 0.7, Zn0: 0.3, B203: 0.5, S1
A glassy powder 48W96 obtained by crushing a product with a molar ratio of 02:0.5 into 200 meshes and 52W% of a synthetic fluorine-containing gold mica powder with a 60 to 150 mesh size were mixed, and 5W of water (F
6 was added to the wet state as a raw material, and another mold (
(not shown) is molded into a cylindrical shape that can be filled with the required amount according to the size and shape of the molded product by cold pressure molding, and kept in a dryer at 120°C to remove moisture. Created.

Iron material was used for the tubular members. Next, regarding the molding conditions, the temperature of the inner and outer molds and the pressurizing metal is 450°C, and the temperature of the "th" tubular member 1, the second tubular member 2, and the molding jig 18 is 550°C.
℃, and the preformed body 12 was press-molded at 650°C. The relationship between the pressure force during pressure molding and the floating blade of the first tubular member 1 will be specifically explained with reference to the structural shape of the insulated pipe joint.

First, the first tubular member 1 and the second tubular member are small-sized products.
The inner diameter of the cylinder of the tubular member 2 is 25 mφ, the outer diameter is 35 Fmφ,
A tubular member having an inner diameter of 41 mφ for the outer peripheral fitting 2-2, an outer diameter of 51 Fmφ for the support portion 1-2, and an inner diameter of 15 mφ for the support portion 1-2 was used, and was formed by the method shown in FIG. The diameter of the upper end of the support stand 7 at this time is 19
It is mφ. The pressure applied to the preformed body 12 by the pressurizing metal 9 is 15t0/C! 1i, the total pressure is 16.2t0n.
The area receiving the levitation pressure at this time is (352192) x π/4
= 6.78 cd and the total floating pressure is 10.16 t0n. However, this value is a calculated value when the internal resistance of the fluid in the preform 12 is ignored; in reality, it is reduced by about 20% to about 8t0n. As mentioned above, the capacity limit of the sub-drive section is generally about 80% of the capacity of the main drive section, so it can be easily manufactured by using a pressure molding machine with a capacity of 50 tons for the main drive section and 10 tons for the sub-drive section. I can do it. Next, regarding large-sized products, the inner diameter of the cylinders of the first tubular member 1 hexagram and the second tubular member 2 is 250 Fmφ, the outer diameter is 300 mφ, the inner diameter of the outer peripheral fitting 2-2 is 312 rmφ, the outer diameter is 362 mφ, and the support part When a tubular member with an inner diameter of 262mm is used as shown in Fig. 1-2 and formed by the method shown in Fig. 2, the diameter of the upper end of the support is 234r.
fr1r1φ. In this case, if the pressing force of the preform 12 is set to 15t0n/d, the pressing area will be 3218cm
r! i, so the total pressure is 482t0n.In this case, the area receiving the levitation pressure is (3002-2842)×π4
The total floating pressure is 276.6cd, which is a calculated value of 415t.
If it is 0n and the rate of decrease due to internal resistance is 20%, the actual floating pressure will be 331t0n. If the capacity of the auxiliary drive section is 331t0n and this is 30% of the main drive section, the main drive section will need a capacity of approximately 1100t0n.
The reality is that without a pressure molding machine with first-half performance, production will be impossible. When the manufacturing method of the present invention is used, no floating pressure is generated, so the main drive section
Production is possible with a pressure molding machine having a pressurizing capacity of 2 tons. As described above, by the manufacturing method of the present invention, 1. a large-sized product that is fully equipped with the characteristics required of small-sized products manufactured by conventional manufacturing methods, such as airtightness, thermal and mechanical impact strength, and reliability against changes over time; The shape-shaped insulated pipe joint does not require a special function, that is, a pressure forming machine that includes a sub-drive section that drives independently in the same direction in the center of the main drive section, and can be used with general pressure forming. It is possible to easily manufacture by using multiple machines, the capacity of the pressure molding machine can be utilized without wasting it, and the increase in the size of the equipment and the complexity of its functions can be avoided, which naturally eliminates the rise in prices. This makes it possible to provide inexpensive products without being constrained by the size of the shape.The practical effects of this are extremely large.

In explaining the present invention, the glass used is lead-containing glass and the tubular member is made of iron. However, it goes without saying that the glass quality is not limited to this type of glass. Enamel glazes for ironware can also be used.

In addition, the tubular member may be made of iron, stainless steel, or steel, and is not particularly limited as long as it maintains mechanical strength comparable to that of iron when heated to about 650°C.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing the structure of an insulated pipe joint, Fig. 2 is a longitudinal sectional view showing a conventional manufacturing method for small-shaped products, and Fig. 2a shows the state immediately before pressure forming. FIG. 2b shows the state after pressure molding is completed.

Claims (1)

[Claims] 1. A first tubular member having a wall tube at one end of the cylindrical body that can be fitted into a cylindrical body having the same inner diameter as the cylindrical body, a cylindrical body of the first tubular member; A second tubular member having a cylindrical body having an inner and outer diameter that is the same as the inner and outer diameters, and a second tubular member having an outer peripheral fitting having an inner diameter larger than the outer diameter of the second tubular member at one end of the cylindrical member. arranging an external mold on the outer periphery and arranging an internal mold in the cylindrical body of the second tubular member; fitting the wall tube of the first tubular member into the cylindrical body of the second tubular member; The process of placing the second tubular member in the internal mold inside the cylinder, press-fitting the raw material that will become the electrically insulating glass or mica plastic body between the outer periphery of the first tubular member and the inner periphery of the second tubular member. Along with molding,
A step of pressing the first tubular member through the raw material to prevent the first tubular member from floating when press-fitting the raw material, and removing the wall tube of the first tubular member to expose the molded plastic body. A method for manufacturing an insulated pipe joint, comprising: adjusting the inner diameter of the cylindrical bodies of the first and second tubular members to match the inner diameter of the exposed plastic body. 2. In the item described in claim 1, the cylindrical body of the first tubular member is provided with a flange on its outer periphery, and when the raw material to be the electrically insulating glass or mica plastic body is press-fitted, the raw material is A method for manufacturing an insulated pipe joint, in which the flange is pressed through the flange to prevent the first tubular member from floating. 3. In the item described in claim 1, a jig is placed on the first tubular member, and when the raw material to be the electrically insulating glass or mica plastic body is press-fitted, the jig is inserted through the raw material. A method for manufacturing an insulated pipe joint, which presses a tool to prevent a first tubular member from floating up.