JPH0244088B2 - ZETSUENKINZOKUBOJOTAINOSEIZOHOHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an insulated metal rod, and more specifically, the invention relates to a method for manufacturing an insulated metal rod, and more specifically, an insulating layer is formed on the outer peripheral surface of a metal tube or a metal rod, and This article relates to a method for producing a long insulated metal rod that maintains high mechanical strength, cold and mechanical impact strength, and high electrical properties in a temperature range of 300°C without peeling or falling off the insulation. be.

Insulated metal rods, which have an insulating material on the outer circumferential surface of the metal tube or metal rod, are used as fixing devices for contactors in circuit breakers. materials are used,
A sheet material wound with mica flakes attached with an organic adhesive as needed is used.

Recently, chemical factories, especially petroleum-related factories,
Transport pipes that transport gas or liquid at operating temperatures as high as 200 to 300 degrees Celsius are now required to have long insulated pipes with an insulating layer on their outer circumferential surfaces. In insulating tubes used under such conditions, if the insulating material is made of an organic material, the insulating material will peel off or fall off when the temperature rises. This is an unavoidable physical phenomenon based on the difference in the coefficient of thermal expansion, and there is absolutely no room for solving it, making it unusable. Among inorganic materials, when porcelain tubular bodies are used, there are gaps, making it difficult to fix and mechanical impact strength cannot be obtained. In the case of composite materials using , it maintains a certain degree of mechanical strength and maintains fairly high electrical insulation properties at high temperatures, but since it is a porous material after all, it encounters high humidity conditions at room temperature. As a result, there are inevitable fatal defects such as sudden deterioration of insulation properties, and the current situation is that there are no conventional products that maintain satisfactory properties.

In this regard, the glass-mica plastic body proposed earlier by the present inventors is used as an insulator, and of course there is no phenomenon such as peeling or falling off even at operating temperatures of around 300℃, and there is no phenomenon of peeling or falling off at room temperature. It maintains high mechanical strength in the temperature range of 300℃ to 300℃, has high cold and mechanical impact strength, and maintains good electrical properties, without deteriorating even when subjected to repeated cold and heat cycles. Although it is an extremely excellent insulator, it had a fatal flaw in the manufacturing method that made it impossible to obtain long products.

This invention has been made with attention to the above points, and uses a glass-mica plastic body as an insulator, and removes a part of the insulator layer at the end of a metal rod-shaped body having a first insulator layer. By preparing a plurality of pieces with exposed metal parts, welding them to each other at the exposed parts, and forming a second insulating layer on the welded joints, the above-mentioned conventional problems are solved. The object of the present invention is to provide a method for manufacturing a rod-shaped body.

Here, in order to facilitate understanding, the characteristics of the glass-mica plastic body and the conventional manufacturing method of the insulating metal rod-shaped body will be explained before a detailed explanation of the present invention.

A glass/mica plastic body is made from a mixture of glassy powder and mica powder, heated to a temperature where the glassy material in the raw material softens and flows during processing, and then press-molded in the heated state. It is an insulator obtained by The properties of this insulator are largely controlled by the properties of the glass used, and those using glass with a transition temperature of about 400°C are
Even when the operating temperature reaches around 300℃, it does not soften and deform, and maintains the same mechanical strength as at room temperature.
Electrical properties are largely related to the composition of the constituent components, and as long as they do not contain extremely large amounts of alkali metal oxides, the properties will not deteriorate significantly even at 300°C, and the necessary insulation properties will be easily ensured. Those containing lead oxide or zinc oxide as the active ingredient and boric acid or silicic acid as the acidic ingredient retain particularly excellent properties.

Next, regarding the mica powder used, when natural mica is mixed with a glassy powder and heated, it reacts with the glassy substance and decomposes by disappearing crystal water at a lower temperature than when heated alone. In this respect, synthetic mica powder that does not contain water of crystallization is ideal because it does not have the above-mentioned tendency, and synthetic fluorine-containing gold mica is particularly suitable.

Next, regarding the coefficient of thermal expansion of the glass-mica plastic body, one having a coefficient of thermal expansion of 8 to 11×10 ⁻⁶ at room temperature or below the transition temperature of glass can be obtained.

A conventional insulating metal rod-shaped body using the above glass-mica plastic body as an insulator is shown in FIGS. 1a and 1b. 1st
Figure a shows an insulating rod, and Figure 1 b shows an insulating tube.
Or it is formed on the outer peripheral surface of the metal tube 3,
The metal rod 2 and the metal tube 3 are preferably those that maintain sufficient mechanical strength under heating conditions of 500 to 600°C and have a coefficient of thermal expansion of 8 to 11 x 10 ^-6 , and steel is preferably used. .

Next, an example of a conventional manufacturing method will be explained with reference to FIGS. 2a and 2b. FIG. 2 shows a method of manufacturing an insulating tube having a metal tube 3 at its center, using a mold. The molding die includes a frame 4, a divided wall 5 having a raw material loading chamber 5-1 at the top, a support 6 having a protrusion 6-1 in the center for fixing the metal tube 3, and a pressurizing mold. Gold 7, consists of the above four parts.

The raw materials are pbO: 1.0 mol, B ₂ O ₃ : 0.3 mol,
SiO ₂ : 35% by volume of powder made by crushing glass with a dislocation temperature of 420°C into 200 mesh with a composition of 1.2 mol.
A mixture of 65% by volume of synthetic fluorine-containing gold mica powder that has been ground into 60 to 100 meshes is used, approximately 5% by weight of water is added to the mixed powder to make it moist, and the mixture is cold-pressed (forming mold). (not shown) into a cylindrical body that can be loaded into the raw material loading chamber 5-1, and used as a preformed body 8 from which moisture has been removed by drying. Further, as shown in FIG. 2, the insulating tube 3 is one in which the upper part of the central through hole is sealed.

For molding, the frame 4, wall 5, and support metal 6 in the mold are assembled as shown in Figure 2a, and the pressure metal 7 is heated to 500°C without being assembled, and the metal tube 3 is heated to 600°C. , the preforms 8 are heated to 800°C. When the heating is completed, the metal tube 3 is loaded onto the support 6 within the wall 5, and then the preform 8 is loaded into the raw material loading chamber 5-1. The state at this time is shown in FIG. 2a. Next, the pressurizing metal 7 is placed on the preformed body 8, and the pressurizing metal 7 is pressurized by a pressure forming machine (not shown), so that the preformed body 8 is composed of the wall body 5 and the metal tube 3. The insulator layer 1 is formed by press-fitting into the space 9.
The state at this time is shown in FIG. 2b. The temperature of insulator layer 1 is 400℃ (lower than the transition temperature of glass)
The mold is disassembled, the molded product is taken out, and the cylindrical insulation layer 1 is machined
The manufacturing process is completed by finishing the insulating tube as shown in FIG. 1b having the following characteristics.

When using the above conventional manufacturing method, the insulating rod or the insulating tube has a short length, with respect to the constructed insulating material layer 1, at a position 1-1 near the pressurizing part and at a position 1-2 at the tip. As mentioned above, products with similar densities and extremely favorable properties can be obtained, but products with long lengths have a fatal flaw in that it is impossible to obtain products that retain desirable properties. The reason for this will be explained below. The raw material, a mixture of glass and mica powder, has extremely high viscosity even when heated, and this viscosity is largely controlled by temperature, decreasing as the temperature rises and rapidly increasing as the temperature decreases. Therefore, the preformed body 8 during molding
The higher the heating temperature, the lower the viscosity, but as the temperature rises, the erosion of the glassy mica becomes more intense, so there is naturally a limit to the heating temperature, which is 800 to 850°C. Furthermore, molding molds are also limited to 500°C due to strength issues. Preformed body 8 pressurized by pressurizer 7 during pressure molding
begins to flow into the space 9, but when the temperature drops in contact with the wall 5, the viscosity increases rapidly and the flow becomes poor, and as the length of the product increases, the tip 1
In case of -2, complete filling is not performed and the density does not increase. Therefore, a uniform insulating layer 1 will not be formed.

Since the above-mentioned phenomenon is unavoidable, a long product cannot be obtained, which is a fatal flaw in the conventional manufacturing method.

This invention completely overcomes the fatal defect of not being able to obtain a long product as described above, and provides a long insulator that not only does not crack the constructed insulating layer but also maintains perfect insulation properties. This was done to obtain pipes and insulating rods, and they succeeded in developing them, established a manufacturing method, and were able to provide long products.

Hereinafter, embodiments of the present invention shown in the drawings will be described. FIG. 3 shows a long insulating tube, and for each of a plurality of short insulating tubes 100 manufactured by a conventional manufacturing method, the insulating layer 1 at the end is removed by machining to expose the metal tube 3, The metal tubes 3 are butted against each other at the exposed portions and joined 10 by a method such as welding to form a long product. 11
is a covering insulator that fills the outer circumferential surface of the joint 10 of the metal tube 3 and the side surface of the insulating layer 1, and also covers a part of the outer circumferential surface of the insulating layer 1 to form a band-like shape. The covering insulator 11 is made of a glass-mica plastic body similar to the insulator layer 1, and is completely fused to the insulator layer 1 to form an integral structure of the insulator. This also applies to insulating rods.

The long product with the above structure has the excellent characteristics that conventional short products have, namely, there is no peeling or falling off even when the operating temperature reaches around 300℃, and there is no phenomenon such as peeling or falling off even when the usage temperature reaches about 300℃ In general, it has to maintain high mechanical strength in a temperature range, has high cold and mechanical impact strength, has high electrical properties, and does not deteriorate even when subjected to repeated heating and cooling. It is equipped with this.

In addition, it is possible to connect three to four or more short insulating tubes 100, which will be explained in detail later in the explanation of the manufacturing method, so that a product of the required length can be obtained, and a long There is no tendency for the above-mentioned necessary characteristics to change even when the product is upgraded.

Next, an example of the manufacturing method will be described.

First, the insulating tube that becomes the base of the covering insulator 11 will be explained with reference to FIG. The figure shows base insulation tube 1
01, an end portion of an insulator 1 formed in a short insulating tube 100 manufactured by a conventional manufacturing method is removed 1-3 by machining to expose a metal tube 3. The exposed end faces of the metal tubes 3 are welded and joined 10. For welding, insulator layer 1 is added during welding.
Electron beam welding is particularly suitable because it causes less temperature rise in the surrounding areas, including the welding process.

Next, the molding molds used for molding are shown in Figure 5 a and b.
This is explained by: The molding mold has a molding part made up of an upper metal 12 and a lower metal 13 whose lower and upper surfaces are in contact with each other, and has a through hole 14 in the center of the contact area into which the base insulating tube 101 can be inserted. A space 19 in which the covering insulator 11 can be formed is provided. Also top money 1
A filling hole 16 communicating with a space 19 is provided in the upper part of the mold 2, and a reservoir 17 is provided in the bottom of the lower mold 13, and a flow hole 1 is provided between the reservoir 17 and the space 19.
8 connects the two. 15 is a raw material filling metal whose lower surface is in contact with the upper surface of the upper metal 12, has a raw material filling chamber 15-1 in the center, and has a raw material filling chamber 15-1 at the bottom thereof.
An outflow hole 15-2 communicating with the filling hole 16 is provided. 20 is a pressurized metal fitting that fits into the inner wall of the raw material filling chamber 15-1. Reference numeral 21 denotes a base metal whose upper surface is in contact with the lower surface of the lower metal 13. Note that the upper metal 12, the lower metal 13, and the raw material filling metal 15 may be divided into two in the vertical direction in consideration of ease of disassembly. However, in that case, measures are required to prevent separation during pressure molding.

Next, the raw material of the coated insulator 11 will be explained.
The same glass and mica as those used in manufacturing the insulating tube 100 are used. It is desirable to increase the mixing ratio of glass somewhat, and a mixture of 40% by volume of glass powder and 60% by volume of mica powder is used. Approximately 5% by weight of water is added to the above mixed powder to make it moist, and it is formed into a cylindrical body that can be loaded into the raw material filling chamber 15-1 by cold pressing (the mold is not shown), and then dried to remove moisture. It is used as a preformed body 22 from which .

The molding is carried out by assembling the base metal 21, the lower metal 13, the upper metal 12, and the raw material filling metal 15 into an integral structure, and then pressing the pressurized metal 20.
is heated to 450°C without assembly, the base insulating tube 101 with the joint 10 is heated to 400°C, and the preform 22 is heated to 750°C.
Heat each to ℃. When the heating is completed, the base insulating tube 101 is inserted into the through hole 14 formed by the upper metal 12 and the lower metal 13 and held so that the joint part 10 is located at the lower part of the filling hole 16. Next, preform 2
2 is loaded into the raw material filling chamber 15-1. The state at this time is shown in FIGS. 5a and 5b. Next, the pressurized metal 20 is placed on the preformed body 22, and the pressurized metal 20 is pressurized by a pressurized molding machine (not shown). The pressurized preform 22 flows, and the outflow hole 15-
2 and the filling hole 16 to reach the upper part of the space 9,
It branches to the left and right of the base insulating tube 101 and flows through the space 19, and the leading portions merge at the lowest part of the space 19.
Next, it passes through the flow hole 18 and reaches the reservoir 17, and the fluid stops flowing after filling the reservoir 17. Further, the density of the fluid increases under pressure, and a covering insulator 11 made of glass/mica plastic is formed.
The state at this time is shown in FIGS. 6a and 6b. When the temperature of the formed insulator 11 reaches 400°C, the mold is disassembled and the molded product is taken out. At this time, the portions of the filling hole 16 and the communication hole 18 are broken, but the breakage hardly causes any damage to the covering insulator 11. Then, if necessary, the surface of the coated insulator 11 is polished to finish the production into a glossy insulator.

In order to connect three to four or more insulating tubes 100, a method is used in which the required number of base insulating tubes 101 are joined 10 and the covering insulator 11 is sequentially formed on each connecting portion 10. In this case, it is not necessary to heat the entire connected base insulating tube 101 to 400°C, but use a ring furnace with both sides open to heat the connection part 10 to 400°C, and locally heat it while maintaining the temperature gradient. It is possible to configure the covering insulator 11 by doing the following.

In the insulating tube according to the present invention manufactured by the above-mentioned manufacturing method, an essential condition is that the constructed insulating material 11 is an insulating layer that is completely bonded and integrated with the insulating material layer 1 and maintains perfect insulating properties. It consists in composing. For this purpose, not only must there be no voids at the contact surface between the insulator layer 11 and the covering insulator 11, but also the occurrence of cracks must not be allowed at all.

The features of the manufacturing method according to the present invention, which can obtain an insulating tube that satisfies the above conditions, will be explained below.

First, as raw materials for the covering insulator 11, 40% by volume of glass powder and 60% by volume of mica powder are used. This is the raw material ratio of glass powder for insulator layer 1.
The content of glass powder is 35% by volume, which is higher than that of mica powder by volume. This is a coated insulator 1 which is a glass-mica plastic body below the glassy transition temperature.
The purpose is to make the coefficient of thermal expansion of the insulator layer 1 smaller than that of the insulator layer 1. As a result, both side surfaces of the insulating coating 11 are compressed by the side surfaces of the insulating layer 1 when the temperature decreases after completion of molding, so that a perfect joint surface with no voids is created.

Next, the raw material preform 22, the base insulating tube 10
Regarding the relationship between 1 and the heating temperature of the molding die, first, the heating of the molding die to 450°C is to maintain the temperature higher than the glassy transition temperature of 420°C so that the preform 22 is cooled. The purpose is to prevent solidification, and if the temperature is too high, the temperature of the insulator layer 1 will rise too much when the base insulating tube 101 is inserted into the through hole 14, which is not desirable. Next, the base insulation tube 1
The heating temperature is 0.01, which is closely related to the transition temperature of the raw material glass. When the temperature of the base insulating tube 101 is raised to a high temperature exceeding this transition temperature, the vitreous viscosity decreases and the tube swells, the density decreases, and the properties essentially deteriorate. Furthermore, if the temperature is too low, cracks will occur when the material comes into contact with the fluidized high-temperature preform 22 and is subjected to pressure. When heated to a temperature slightly lower than the dislocation temperature of the raw material glass, no swelling phenomenon is observed, and even when it comes into contact with the high-temperature preform 22 and is subjected to pressure, no cracks occur at all, and no dislocation occurs. than temperature
It is desirable to set the temperature 20-40 degrees Celsius lower. In the above example, the temperature was set at 400°C, which is 20°C lower than the glass transition temperature of 420°C. Furthermore, regarding the heating temperature of the preform 22, it is an essential condition that the preform 22 be heated to a temperature at which it has a viscosity that allows it to flow under pressure and form the covering insulator 11 with equal density in each part. In order to minimize the thermal effect on the material layer 1 and the absolute amount of shrinkage, it is desirable that the temperature be as low as possible, and in the example, it was set at 750°C.

Finally, regarding the structure of the mold, a major feature is that a reservoir 17 having a flow hole 18 is provided at the bottom of the lower mold 13. As a result, during molding, the preformed body 22 pressurized by the pressurizing metal 20 is placed in the outflow hole 1.
5-2 and the filling hole 16, and the upper metal 12 and the lower metal 1
The space 1 formed between 3 and the base insulating tube 101
It reaches the top of 9, where it branches left and right and flows.
They collide and coalesce at the lower part of the base insulating tube 101, and the combined part passes through the flow hole 18 and reaches the reservoir 17.
is filled and the flow stops. After that, pressurize gold 20
Preformed body 22 whose flow has stopped due to pressure applied by
The density of the glass-mica plastic material increases, and a covering insulator 11 made of a glass-mica plastic body is formed. In addition, the filling hole 16
The preformed body 22 that has passed through is branched left and right, flows, collides with the lower part of the base insulating tube 101, and is combined, but the leading part of the preform 22 flows between the mold wall for molding and the base insulating tube 10.
Since it is flowing in contact with the surface of 1, the temperature is decreasing. Therefore, the joint surfaces formed by collision cannot maintain a completely fused state. If the molding die does not have the reservoir 17, a joint surface that does not maintain the above-mentioned completely fused state will appear at the bottom of the base insulating tube 101, causing cracks and impairing its mechanical and electrical properties. Although the molding die according to the present invention is provided with a reservoir portion 17 and a communication hole 18 that communicates with the reservoir portion 17, the joint portion that does not maintain the above-mentioned completely fused state is caused by the communication hole 18. It passes through and is pushed out into the reservoir 17, forming a bonding surface that maintains a completely fused state at the bonded portion at the bottom of the base insulating tube 101.

For the above reasons, the coated insulator 11 formed by the manufacturing method according to the present invention is completely free from cracks. In addition, since the flow distance of the preform 22 is extremely short compared to conventional manufacturing methods,
The density of each portion of the molded insulation covering 11 is extremely uniform.

Note that although the above embodiments were directed to the manufacture of insulating tubes, the manufacturing method of the present invention is not limited to this, and can also be applied to insulating rods, and can be applied to products with a rectangular shape instead of a circular cross section. It also applies to

As is clear from the above description, according to the manufacturing method of the present invention, it has become possible to easily obtain long insulating metal rods such as long insulating tubes or insulating rods, which were previously unobtainable. Moreover, this long product has the excellent properties that conventional short products have, such as no cracking, and can be used at room temperature.
It maintains high mechanical strength and high electrical insulation properties in the temperature range of 300°C, and has excellent long-term reliability with no property deterioration due to aging. In addition, it is used in a wide range of applications as a component that maintains stable properties, making it possible to improve the properties and downsize equipment and equipment, and its technical and economical effects are extremely large.

[Brief explanation of the drawing]

Figure 1 shows a conventional insulated metal bar;
Figure 2 shows the insulating bar, Figure b shows the insulating tube, and Figure 2 is for explaining the conventional manufacturing method. 3 to 6 are views for explaining an embodiment of the present invention, and FIG. 3 is a partially longitudinal front view of the completed product, Figure 4 is a longitudinal sectional front view for explaining the first process, Figures 5 a and b are a partially sectional front view and a partially sectional side view showing the state immediately before pressure forming, respectively, and Figures 6 a and b. These are a partially sectional front view and a partially sectional side view, respectively, showing the state after pressure molding is completed. DESCRIPTION OF SYMBOLS 1...Insulator layer, 2...Metal rod, 3...Metal tube, 10...Joint part, 11...Coated insulator, 12
...Top metal, 13...Bottom metal, 14...Through hole, 15
...Raw material filling money, 15-1...Raw material filling room, 15
-2... Outflow hole, 16... Filling hole, 17... Reservoir, 18... Distribution hole, 19... Space, 20...
Pressure metal, 21... base metal, 22... preformed body, 1
00... Insulating tube, 101... Base insulating tube (base insulating rod). In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. Through-holes are formed in contact with each other to insert and hold the base insulating rods, and when the base insulating rods are inserted into the through-holes, the joined portions of the base insulating rods are wound. A space is formed in the space, and the space has a filling hole communicating with the upper surface, a communication hole communicating with the bottom surface, and a reservoir communicating with the communication hole, and an upper metal plate and a lower metal plate that can be disassembled from each other; A molding die consisting of a raw material filling chamber with a raw material filling chamber having an outlet leading to a filling hole and a pressurizing metal inserted into the raw material filling chamber is used, and a glass-mica plastic body is formed on the outer peripheral surface. a first step of forming the base insulating rod-like body by removing a part of the insulating layer and butt-welding the ends of two metal rod-like bodies on which insulating layers are formed; a second step of forming a preformed body made of a glass-mica plastic body of a covering insulator to be applied to the welded joint; a third step of heating each preform to a predetermined temperature; a fourth step of inserting and holding the heated base insulating rod into the through hole; and loading the preform into the raw material filling chamber. The preform is pressurized by the pressurizing metal, and the preform is press-fitted from the outlet through the filling hole into the base insulating rod and the space, and further through the communication hole into the reservoir to cover the coating. a fifth step of forming an insulator; a sixth step of disassembling the molding die to take out the molded product after cooling to a predetermined temperature; and performing machining on the molded product to finish it into a long product. A method for manufacturing an insulated metal bar, comprising a seventh step.