KR20060013555A - Heat-resistant protective tube, method for producing same, and apparatus for producing heat-resistant protective tube - Google Patents

Abstract

A heat-resistant protective tube (1) is composed of a material obtained by binding wollastonite or a heat- resistant inorganic powder containing 20 weight% or more of wollastonite with use of 1.5-15 weight% of an additive. The heat-resistant protective tube (1) can be produced by mixing wollastonite or the heat-resistant inorganic powder with the additive and an adequate amount of water or an organic solvent, thereby preparing a mixed material, then forming the mixed material into a tubular shape, and drying the thus-formed tubular body.

Description

TECHNICAL FIELD [0001] The present invention relates to a heat-resistant protection tube, a method of manufacturing the same, and a manufacturing apparatus for a heat-resistant protection tube.

TECHNICAL FIELD The present invention relates to a heat-resistant protective pipe that can be used for applications such as protecting a measuring means such as a thermocouple from a high temperature, a method for manufacturing the same, and an apparatus for manufacturing a heat-resistant protective pipe.

Conventionally, the temperature of the molten metal is measured by immersing the probe in molten metal at about 1000 캜 to 1700 캜 for 5 to 10 seconds. In general, a paper tube has been used as the probe. However, water and organic components contained in the paper tube are rapidly vaporized and burned at a high temperature, and the molten metal is scattered by the gas generated at that time, Workers may be at risk. In addition, since the paper tube is easy to burn and disappears in a short time, there are many cases in which the holder can not be sufficiently performed, for example, at a high temperature of 1600 占 폚 or more.

Therefore, as an outer cover material of a paper tube, it is possible to use a paper product obtained by dispersing a clay mineral in a ceramic fiber, a product obtained by kneading a binder in a ceramic fiber to form a tubular shape, or a product obtained by kneading a ceramic diatomaceous earth, alumina, silica, Glass fibers and rock wool are mixed and reinforced. An example of a protective pipe for molten metal immersion is disclosed, for example, in Japanese Utility Model Publication No. 3-45152.

Patent Document 1: Japanese Utility Model Publication No. 3-45152

SUMMARY OF THE INVENTION

The above-mentioned edible product is wrapped around the outer circumference of the paper tube, and a step difference is produced by the thickness of the article to be wrapped at the end of the wrapping, and the number of times of wrapping varies depending on the place, There is a growing tendency.

Further, the ceramic fiber molded article is adhered to the paper tube, and at this time, a gap is formed between the ceramic fiber molded article and the paper tube, and the fiber is strongly weakened. For this reason, there is a case where a shock at the time of transportation or a pressure at the time of fitting into the stationary clamp at the time of mounting on the automatic injector is broken.

In the case of using diatomaceous earth or the like, since it has a crystal number in the unfilled state, when it is immersed in the molten metal, it is rapidly vaporized and released, and a phenomenon of scattering of the molten metal called splash may occur. For this reason, diatomaceous earth fired at a temperature of about 1000 ° C or higher is often used, but fired diatomite also readily absorbs atmospheric moisture and absorbs moisture in the atmosphere during periods of high humidity such as rainy season. Therefore, it is difficult to sufficiently prevent splashing.

In recent years, it has been pointed out that ceramics, artificial amorphous fibers and powders adversely affect the human body. From IARC (International Agency for Research on Cancer), it has been reported that cristobalite contained in ceramics fiber or calcined diatomaceous earth Powder, glass fiber, and rocky surface.

Disclosure of the Invention The present invention has been made to solve the above problems, and it is an object of the present invention to prevent scattering of an object to be measured when it is used as a protective tube for measuring a temperature and an oxygen concentration by immersing in an object to be measured at a high temperature, A heat-resistant protective tube excellent in heat resistance, heat insulating property and impact resistance, and made of a material having a small adverse effect on the human body, a method for manufacturing the same, and an apparatus for manufacturing the heat-resistant protective tube.

Means for solving the problem

The heat-resistant protection pipe according to the present invention is made of a material obtained by bonding heat resistant inorganic powder containing wastedite or wollastonite in an amount of 1.5 wt% or more and 15 wt% or less in terms of solid content.

Wollastonite is a material which hardly absorbs moisture in the atmosphere and has almost no crystal number, so that splash can be effectively suppressed. Also, wollastonite is a material excellent in heat resistance and mono-aging property, and the protective tube manufactured using the wollastonite has a strength higher than that of the prior art. Furthermore, there is no indication that Wurassonite is adversely affecting the human body. Therefore, it is possible to suppress scattering (splash) of an object to be measured when the object is immersed in the object to be measured, and it is possible to obtain a heat-resistant protection tube that is excellent in heat resistance, heat insulation and impact resistance and further, has little adverse effect on the human body.

The additive includes at least one of, for example, an organic dispersant, an organic binder, and an inorganic binder. Further, the wollastonite is preferably acicular wollastonite.

A method for manufacturing a heat-resistant protective pipe according to the present invention comprises the following steps. A heat resistant inorganic powder containing at least 20 wt% of wollastonite or wollastonite, at least 1.5 wt% and at most 15 wt% of an additive in terms of solid content, and water or an organic solvent are mixed to prepare a mixed material. And the mixed material is formed into a tubular shape to produce a tubular shaped body. The tubular shaped body is dried.

The inventors of the present invention have been made aware of the fact that by using the above-mentioned method, it is possible to produce a heat-resistant protective tube having excellent properties as described above, using a material containing wollastonite.

It is preferable that the tubular shaped body is formed by extrusion molding. Further, the heat-resistant protective pipe may be formed on the outer peripheral surface of the paper tube. In this case, the manufacturing process of the tubular shaped body includes a step of manufacturing the tubular formed body on the outer peripheral surface of the paper tube by moving the paper tube in the axial direction while extruding the mixed material onto the outer peripheral surface of the paper tube, The drying step includes a step of drying the tubular shaped body on the outer peripheral surface of the paper tube. In addition, it is preferable that the flow of the mixed material is locally narrowed by providing a place where the flow path area of the mixed material is reduced.

The apparatus for manufacturing a heat-resistant protective pipe according to the present invention is a device for forming a heat-resistant protective pipe on the outer circumferential surface of a paper tube, comprising a cylinder for mixing and supplying a material therein, a space And a molding die having a flow path for guiding the material supplied from the cylinder onto the outer peripheral surface of the paper tube. A neck portion for locally reducing the area of the flow path is provided in the flow path of the material positioned in the forming die.

As described above, since the apparatus for manufacturing a heat-resistant protective pipe includes the space portion for receiving the paper tube and the forming die having the flow path for guiding the material supplied from the cylinder onto the outer peripheral surface of the paper tube, The material can be supplied onto the outer circumferential surface of the paper tube from the cylinder through the flow path in the forming die while the paper tube is inserted into the portion. Thereby, the heat-resistant protective pipe can be formed on the outer peripheral surface of the paper tube. At this time, by providing the above-mentioned neck portion in the flow path in the molding die, the material can be brought into a compact state, and the material in the compact state can be supplied onto the outer peripheral surface of the paper tube.

Effects of the Invention

According to the present invention, since the heat resistant protection pipe is manufactured using wollastonite, it is possible to suppress scattering (splash) of the measured object when it is immersed in the measured object, and is excellent in heat resistance, heat insulating property and impact resistance It is possible to obtain an anti-aging protective tube having a small adverse effect on the human body.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view of a heat-resistant protective tube according to one embodiment of the present invention. Fig.

2 is a partial cross-sectional view of a lance thermocouple using the heat-resistant protective tube shown in Fig.

3 is a sectional view showing an example of a holder for a lance thermocouple shown in Fig.

4 is an enlarged cross-sectional view of a head portion of an apparatus for manufacturing a heat-resistant protective pipe according to one embodiment of the present invention.

5 is a view showing the relationship between the amount of the additive and the bending strength of the heat resistant protective pipe material.

6 is a view showing the relationship between the content of wollastonite and the bending strength of a heat resistant protective tube material;

Explanation of symbols

1: heat-resistant protective tube 2: paper tube

3: Temperature detection stage 4: Cap

5: Connector block 6: Poles

7: Copper sheath compensation lead 8: Extension pipe

9: Cap tire compensation lead 10: Handle

11: metal connector 12: cylinder

13: Mixed material 14: Molding mold

15: space part 16: upper pressure plate

17: Inner pipe 18: Euro

19: detention 20: neck

21: Lower presser plate

Carrying out the invention  Best form for

Hereinafter, embodiments of the present invention will be described with reference to Figs. 1 to 4. Fig.

The heat resistant protection pipe in the present embodiment is a heat resistant protection pipe which is made of heat resistant inorganic powder containing at least 20 wt% (preferably at least 40 wt%) of wollastonite or wollastonite in an amount of 1.5 wt% to 15 wt% Preferably 3 wt% or more and 10 wt% or less, and more preferably 3 wt% or more and 57 wt% or less).

Further, in the present specification, the amount of wollastonite, heat-resistant inorganic powder and additive is an amount based on solid content conversion. The amount of the additive added when the heat resistant inorganic powder and the wollastonite are mixed is an amount relative to the total amount of the heat resistant inorganic powder and the wollastonite.

Further, even when the content of wollastonite in the heat-resistant inorganic powder is less than 20% by weight, it should be interpreted that it is equivalent to the heat-resistant protective tube in this embodiment as long as the effects described later can be obtained. The amount of the additive is also equivalent to that of the heat resistant protective tube in this embodiment even if the amount of the additive is less than 1.5 wt% or more than 15 wt% something to do.

Wollastonite (melting point: about 1500 ° C, hardness (moss): about 4.5 to 5.0) is a silicate mineral represented by the formula CaSiO ₃ . Wollastonite, which is produced as natural minerals, is a mineral developed by metamorphism at the contact area of limestone and granite. The color is white with white luster, tournament color, and brown (dark brown). Crystalline forms of wollastonite are acicular and massive. Wollastonite contains substantially equal amounts of SiO ₂ and CaO as main components, and Al ₂ O ₃ and Fe ₂ O ₃ as minor constituents.

Since the wollastonite has little hygroscopicity, when the heat-resistant protective pipe made of the material containing the wollastonite is immersed in the object to be measured at a high temperature such as molten metal, moisture contained in the heat- Vaporization can be suppressed, and scattering (splashing) of the object to be measured accompanying therewith can be effectively suppressed. Furthermore, since wollastonite is excellent in heat resistance and heat insulation property, it is also possible to suppress burning of the sensor portion and the paper tube in the heat-resistant protective pipe.

Further, by using walastonite as the material of the heat-resistant protective pipe, it is possible to secure the strength of the heat-resistant protective pipe, and to prevent the heat-resistant protective pipe from being damaged by external force applied during transportation, pressure at the time of clamping, and the like.

In addition, the International Agency for Research on Cancer (IARC) reports from studies on chronic toxicity that walassonite does not cause tumors and can not classify walassonite as a carcinogen. From this, it can be said that walastonite is a safe substance compared with rock wool.

As the heat-resistant protection pipe of the present embodiment, acicular (fibrous) wollastonite is preferably used. Thereby, not only the strength of the heat-resistant protective pipe can be improved, but also it is not necessary to add a rock surface or glass fiber for reinforcement. Therefore, the adverse effect on the human body can be suppressed more effectively.

Examples of heat-resistant inorganic powders usable in the present embodiment include inorganic materials such as diatomaceous earth, alumina, zirconia, mullite, cordierite, zircon, magnesia, calcia, stearate, talc, silicon carbide, silicon nitride, Ceramic powder having a particle size close to 1 may be used alone or in combination.

The use of the particulate ceramic powder having an aspect ratio close to 1 improves the moldability of the heat resistant protective tube and improves the surface smoothness of the heat resistant protective tube. Further, by selecting a ceramic powder excellent in heat resistance, the heat resistance of the heat-resistant protective pipe can be improved, and splash can be suppressed by selecting a ceramics powder with no crystal number. In addition, by using the ceramic powder having a particulate shape whose aspect ratio is close to 1, which does not indicate the carcinogenicity, a heat-resistant protective tube with less harmfulness to the human body can be obtained.

The additive that can be used in the present embodiment includes at least one of, for example, an organic dispersant, an organic binder, and an inorganic binder. As the organic dispersant, for example, polyacrylate, polycarbonate, ligninsulfonate, hexametaphosphate and the like can be used. As the organic binder, for example, polyvinyl alcohol, methylcellulose, carboxymethylcellulose, emulsified (vinyl acetate) acetate and the like can be used. As the inorganic binder, for example, silica sol, alumina sol, silica sol-alumina sol mixture, lithium silicate, silicate, phosphate and the like can be used.

Next, a structural example of the heat-resistant protective pipe according to the present embodiment will be described with reference to Fig. Fig. 1 is a view showing an example of the structure of a heat-resistant protective pipe in the present embodiment.

As shown in Fig. 1, the heat-resistant protective pipe 1 is formed on the outer peripheral surface of the paper tube 2, for example. The heat-resistant protective pipe 1 can be used as a protective tube for immersing in a molten metal and measuring the temperature and oxygen concentration of the molten metal. More specifically, it can be used as a protective tube of a lance thermocouple.

When both ends of the dissimilar metal are electrically connected and a temperature difference is applied to both ends, a current flows in the circuit due to the Seebeck effect. Using this principle, it is the lance thermocouple that is immersed directly in the molten metal to measure the temperature.

Fig. 2 shows a partial sectional view of a lance thermocouple using the heat-resistant protective tube 1 shown in Fig. As shown in Fig. 2, the lance thermocouple has a temperature detecting stage 3 provided inside the paper tube 2 and a cap 4 attached to the front end of the heat resistant protective tube 1. As shown in Fig.

When a lance thermocouple is immersed in a molten metal, a mechanism called a holder is often used. An example of this holder is shown in Fig. 3, the holder includes a connector block 5, a pawl 6, a copper sheath compensation lead 7, an extension pipe 8, a cap tire compensation lead 9, (10), and a metal connector (11). A lance thermocouple is attached to the tip of the holder together with the heat resistant protection tube 1 described above, and these are directly immersed in the molten metal to measure the temperature of the molten metal.

Further, the heat-resistant protective pipe of the present embodiment can be used as a protective pipe (thermocouple protection pipe) for molten metal immersion as described above, but can be used for other purposes. For example, there is a need for heat resistance, such as a hot-water insulation material, a heat-resistant pipe for flowing a high-temperature fluid such as molten metal, a heat-insulating material provided outside a pipe through which a hot fluid flows, It can be used for shape part.

Generally, when a metal is molded by casting, since the metal shrinks, the molten metal is allowed to flow into the mold excessively. If the portion to which the molten metal flows into the excess becomes harder than the portion to be the product, the product is damaged. Therefore, the portion into which the molten metal is injected as an extra is kept warm, and the molten metal in the portion hardens finally. As described above, it is the above-mentioned hot-tap insulating material that is used when the molten metal is warmed by being installed around the portion where the molten metal flows in excess. Since the molten metal is in contact with the inside of the protective pipe when it is used for this purpose, it is necessary to remove the paper pipe, or to remove the paper pipe by using a water repellent material or a material having the material disposed on the surface thereof .

Next, a method of manufacturing the heat-resistant protection pipe according to the present embodiment will be described. The heat-resistant protective tube according to the present embodiment is produced by first preparing heat-resisting inorganic powder containing at least 20 wt% (preferably at least 40 wt%) of wollastonite or wollastonite and at least 1.5 wt% (Preferably 3 wt% or more and 10 wt% or less, more preferably 3 wt% or more and 57 wt% or less) and an appropriate amount of water or an organic solvent are mixed (kneaded) to prepare a mixed material . The mixed material is typically clay (clay), and the mixed material is formed into a tubular shape to produce a tubular shaped body. Then, the tubular shaped body is dried.

The above tubular shaped body is preferably formed by extrusion molding. Thereby, a tubular shaped body having a uniform thickness can be easily manufactured. Further, the heat-resistant protective pipe may be formed on the outer peripheral surface of the paper tube. In this case, for example, a paper tube is moved in the axial direction (longitudinal direction) while the mixed material is being extruded on the outer circumferential surface of a paper tube, thereby producing a tubular formed body on the outer circumferential surface of the paper tube, .

At this time, it is preferable that the flow of the mixed material is locally narrowed by providing a place where the flow path area is reduced in the flow path of the mixed material. Thereby, the mixed material can be dense and a high-quality heat-resistant protective pipe can be obtained.

Next, an apparatus for manufacturing a heat-resistant protective pipe according to the present embodiment will be described. When the heat-resistant protection tube is formed on the outer peripheral surface of the paper tube, for example, the heat-resistant protection tube can be formed by using the manufacturing apparatus having the head portion shown in Fig.

As shown in Fig. 4, the apparatus for manufacturing a heat-resistant protective pipe according to the present embodiment includes a cylinder 12 for mixing and supplying a material therein and a molding die 14. The molding die 14 has a space 15 connected to the front end of the cylinder 12 and receiving the paper tube 2 and a flow passage 18 of the mixed material 13 supplied from the cylinder 12 .

In the example shown in Fig. 4, the cylinder 12 extends in the direction intersecting the longitudinal direction of the forming die 14 (the axial direction of the paper tube 2), and has a screw (not shown) therein. The mixed material 13 is fed to the tip end side of the cylinder 12 while the mixed material 13 is being produced by mixing the materials by rotating the screw so that the mixed material 13 is fed into the forming die 14 from the tip of the cylinder 12 .

The tip end of the cylinder 12 is fitted into the molding die 14 and the space in the cylinder 12 accommodating the mixed material 13 and the space of the flow path 18 of the mixed material 13 provided in the molding die 14 ). Thereby, the mixed material 13 can be fed into the forming die 14 from the inside of the cylinder 12 into the flow path 18.

4, the upper press plate 16 and the lower press plate 21 are provided at both ends in the longitudinal direction of the forming die 14, and the upper press plate 16 and the lower press plate 21 form the molding die 14 . An inner tube 17 is mounted on the inner side of the molding die 14 and a part of the space 15 is defined by the inner circumferential surface of the inner tube 17. [ A flow path 18 is formed between the outer circumferential surface of the inner pipe 17 and the inner surface of the forming die 14.

On the inner side of the lower presser plate 21, a tubular needle mouth 19 is mounted. A tapered portion is provided on the inner circumferential surface of the nipping portion 19 and a place where the area of the flow path 18 is locally reduced is provided between the tapered portion and the distal end portion of the inner tube 17. [ That is, a neck portion 20 is provided in the flow path 18 of the mixed material 13 located in the forming die 14, the flow path area of the mixed material 13 being locally reduced. The neck portion 20 may be provided in the flow path 18 of the mixed material 13 by any other method.

Next, a method of forming the heat-resistant protective pipe on the outer peripheral surface of the paper tube 2 will be described using the apparatus for manufacturing a heat-resistant protective tube in this embodiment.

The paper tube 2 is inserted into the inside of the inner tube 17, that is, into the space 15 of the forming die 14, as shown in Fig. In this state, the cylinder 12 is operated to supply the mixed material 13 after kneading from the inside of the cylinder 12 to the flow path 18 in the forming die 14.

The mixed material 13 flows from the right side to the left side in Fig. 4, is extruded from the inside of the cylinder 12, and is fed into the forming die 14. The mixed material 13 fed into the molding die 14 collides against the outer peripheral surface of the inner tube 17 and the flow direction changes by about 90 degrees. Thereafter, the mixed material 13 moves along the outer peripheral surface of the inner tube 17 from the upper side to the lower side in Fig. 4, is tightened by the neck portion 20, and then supplied onto the outer peripheral surface of the paper tube 2.

By feeding the mixed material 13 onto the outer circumferential surface of the paper tube 2 after joining the flow path area by the neck portion 20 as described above, the dense mixed material 13 is uniformly supplied onto the outer peripheral surface of the paper tube 2 Can supply. Therefore, it is possible to form the heat-resistant protective pipe having a smooth thickness and a uniform thickness on the outer peripheral surface of the paper tube 2.

The paper tube 2 is moved in its axial direction (from the upper side to the lower side in Fig. 4) while supplying the mixed material 13 onto the outer peripheral surface of the paper tube 2 as described above. Thereby, the heat-resistant protective pipe can be continuously formed on the outer peripheral surface of the paper tube 2. After forming the heat-resistant protective tube in this way, the heat-resistant protective tube is dried on the outer surface of the paper tube 2, whereby the heat-resistant protective tube can be manufactured on the outer peripheral surface of the paper tube 2.

Hereinafter, embodiments of the present invention will be described with reference to Tables 1 to 4 and Figs. 5 and 6. Fig.

(Example 1)

About 10% by weight in terms of solid content was added to wollastonite having an average particle size of 17.6 탆 and an aspect ratio of about 10 to 20 by using an aqueous solution of sodium polycarboxylate as an organic dispersing agent, carboxymethyl cellulose as an organic binder and silica sol as an inorganic binder 100% by weight, ion exchange water equivalent to 80% by weight thereof is added, and the mixture is stirred and mixed with a Henschel mixer to prepare a clay-shaped molding material. The formed molding material was sandwiched in a mold of 20 mm x 20 mm x 80 mm and heated and dried to prepare a test piece. This test piece was subjected to a three-point bending test by an autograph, and the fracture strength was measured.

In addition, a test piece was similarly prepared with the formulation shown in Table 1 below, subjected to a three-point bending test, and the fracture strength was measured. The results are shown in Fig. As the conventional product (2) in Fig. 5, 10% by weight of an aqueous solution of sodium polycarbonate as an organic dispersant, carboxymethyl cellulose as an organic binder, and silica sol as an inorganic binder was added as an additive to diatomaceous earth.

From the results shown in Fig. 5, it can be seen that all of the test pieces have higher bending strength than the conventional product (2). It has been found that there is no problem in terms of strength in actual use for the conventional product (2), so it can be said that the test pieces having higher bending strength than the conventional product (2) . That is, it is presumed that by using a material in which the additive is added to the wollastonite group in an amount of about 1.5 wt% or more, a heat-resistant protective tube that can be used without any problem in strength can be obtained.

From the results shown in Fig. 5, it is expected that the bending strength as in the conventional product (2) can be obtained even when the amount of the additive is about 1.0% by weight. . In addition, it was confirmed from the results of FIG. 5 that the bending strength of the test piece tends to increase as the amount of the binder increases, and the amount of the additive is 15 wt% It is presumed that a heat-resistant protective pipe that can be used without any problem of strength is obtained.

(Example 2)

An aqueous solution of sodium polycarbonate as an organic dispersing agent, carboxymethyl cellulose as an organic binder and silica sol as an inorganic binder were added to about 80 wt% of wollastonite having an average particle size of 17.6 탆 and an aspect ratio of about 10 to 20 and 20 wt% The amount of the addition of about 7% by weight (ratio of wollastonite to diatomaceous earth) to the total amount of wollastonite and diatomaceous earth in terms of solid content was determined to be 100% by weight, ion-exchanged water equivalent to 70% by weight thereof was added and stirred with a Henschel mixer A clay-phase molding material is produced. The formed molding material was sandwiched in a mold of 20 mm x 20 mm x 80 mm, and heated and dried to prepare a test piece. This test piece was subjected to a three-point bending test by an autograph, and the breaking strength was measured.

In addition, a test piece was similarly prepared with the formulation shown in Table 2 below, subjected to a three-point bending test, and the fracture strength was measured. The results are shown in Fig. As the conventional product (2) in Fig. 6, 10% by weight of an aqueous solution of sodium polycarboxylate, an organic binder, carboxymethyl cellulose and an inorganic binder silica, which is an organic dispersant, was added to the diatomaceous earth.

As shown in Fig. 6, the higher the content of wollastonite, the higher the strength of the test piece. Specifically, it can be seen that the strength of the conventional product (2) or more can be obtained if the wollastonite is about 20% by weight or more.

It can also be seen that the strength of the test piece varies due to the amount of the additive. That is, it can be seen that as the amount of the additive increases, the strength of the test piece increases. Therefore, when the amount of the additive is about 7 wt%, the amount of the wollastonite is about 20 wt% or more, and the amount of the additive is about 5 wt% It can be seen that when wollastonite is about 30 to 40 wt% or more and the amount of additives is about 3 wt%, wollastonite is required to be about 70 to 80 wt% or more.

(Example 3)

10% by weight in terms of solid content was added to wollastonite having an average particle size of 17.6 占 퐉 and an aspect ratio of 10 to 20 占 using an aqueous solution of sodium polycarboxylate as an organic dispersing agent, carboxymethyl cellulose as an organic binder and silica sol as an inorganic binder as additives Ion-exchanged water corresponding to 80 wt% of the ion-exchanged water is added to the resulting mixture, and the mixture is stirred and mixed by a Henschel mixer to produce a clay-shaped molding material. The formed molding material is put in a vacuum extrusion molding machine cooled to about 5 캜 to obtain a pipe-shaped molded body. Thereafter, the pipe-shaped molded body is heated and dried to produce a heat-resistant protective pipe. By bonding the inner circumferential portion of the heat resistant protective tube and the outer circumferential portion of the paper tube with sodium silicate, a protective tube for molten metal immersion, which is a heat resistant protective tube, can be manufactured.

(Example 4)

An average particle diameter of 17.6 mu m and an aspect ratio of about 10 to 20, an aqueous solution of sodium polycarboxylate as an organic dispersing agent, carboxymethylcellulose as an organic binder, silica sol and alumina sol as inorganic binders, %, Ion-exchanged water corresponding to 70% by weight is added to the weight, and the mixture is stirred and mixed with a Henschel mixer to prepare a clay-shaped molding material. The formed molding material is put into a vacuum extrusion molding machine cooled to about 5 캜.

The vacuum extrusion molding machine used in the fourth embodiment has the head portion shown in Fig. A paper tube is inserted into a space portion provided at the center of the mouth of the head of the vacuum extrusion molding machine and the mixed material is supplied from the cylinder of the vacuum extrusion molding machine to the outer peripheral surface of the paper tube through the flow path in the head. Then, while feeding the mixed material onto the outer peripheral surface of the paper tube, the paper tube is moved in its axial direction (longitudinal direction). Thereby, the cylindrical shaped article can be formed on the outer peripheral surface of the paper tube. This is put in a drier at 60 캜 for 8 hours and dried to obtain a protective pipe for molten metal immersion, which is a heat resistant protective pipe in the present Example 4. [ In addition, the drying may be naturally dried or the same protective tube may be obtained even if left for 4 days from the 2nd day.

Since the protective tube of the fourth embodiment is manufactured by applying the material directly on the outer peripheral surface of the paper tube and drying it as described above, it is possible to obtain high adhesion between the paper tubes without using an adhesive, .

(Example 5)

Heat resistant inorganic powder containing about 80% by weight of wollastonite having an average particle size of 17.6 탆 and an aspect ratio of about 10 to 20 and about 20% by weight of diatomaceous earth having an average particle diameter of 10 to 20 탆, an aqueous sodium polycarbonate solution By weight of carboxymethyl cellulose as a binder, silica sol as an inorganic binder and alumina sol as an additive were added in an amount of about 3% by weight in terms of solid content (ratio with respect to the total amount of wollastonite and diatomaceous earth) Ion exchanged water is added, and the mixture is stirred and mixed by a Henschel mixer to produce a clay-shaped molding material. The formed molding material is put into a vacuum extrusion molding machine cooled to about 5 캜.

Also in the case of the fifth embodiment, a vacuum extrusion molding machine having a head part similar to that of the above-described fourth embodiment is used, a paper tube is inserted into the head of the vacuum extrusion molding machine, the air is passed from the cylinder of the vacuum extrusion molding machine The mixed material is supplied onto the outer peripheral surface of the paper tube. Then, while supplying the mixed material onto the outer peripheral surface of the paper tube, the paper tube is moved in its axial direction (longitudinal direction) to form a tubular formed body on the outer peripheral surface of the paper tube. This is put in a drier at 60 DEG C for 8 hours and then dried to obtain the heat resistant protection tube in the fifth embodiment. In addition, the drying may be naturally dried or the same heat-resistant protective tube may be obtained even if left for two days to four days.

(Example 6)

(Conventional product (1)), a diatomaceous earth molded product (conventional product (2)), a ceramic fiber molded product (conventional product (3)) wrapped in a conventional paper product Since the inventive articles prepared by the methods of Examples 4 and 5 were prepared at the compounding ratios and the performance was evaluated for each of them, the results will be described with reference to Tables 3 and 4.

In this evaluation, three small lance thermocouples were fabricated using the above-mentioned protective tubes, and their performance was evaluated. In the present evaluation, the most severe steelmaking site was assumed, and the lance thermocouple was immersed in molten steel at 1700 DEG C for 15 seconds to observe the degree of splash and the debris after pulling, . The results are shown in Tables 3 and 4.

As shown in Table 3, in the conventional products, all of the four performances of splash, heat resistance, heat insulation and impact resistance were not satisfied, but as shown in Table 4, the present invention satisfies all of the four performances It can be seen that there are many.

Specifically, when the wollastonite is 100 wt%, the additive is 3 wt% or more and 5 wt% or less. When the wollastonite is 90 wt% and the diatomite is 10 wt%, the additive is 5 wt% By weight, the wollastonite is not less than 40% by weight and not more than 80% by weight, and the diatomaceous earth is not less than 60% by weight and not more than 20% by weight, It can be seen that a protective tube having excellent performance can be obtained.

Even outside the numerical range described above, it is considered that the same effect can be expected if it is in the vicinity of the numerical value range. For example, when the amount of the additive is less than 3% by weight or greater than 5% by weight in the case of 100% by weight of wollastonite, excellent performances of satisfying all of the above four performances It is thought that there may be cases where a protective shield can be obtained. Therefore, even when the above-mentioned numerical range is outside the range, it can be interpreted that the same effect as that of the heat-resistant protective tube of the embodiment can be obtained, which is equivalent to the heat-resistant protective tube of the embodiment.

(Example 7)

Next, the strength evaluation by the bending test was carried out on the conventional product and the present invention, and the results are described with reference to Tables 5 and 6. Fig. Table 5 lists the materials and additive amounts of each conventional product and the present invention, and Table 6 lists the test results. As the bending test, a three-point bending test was performed at a point-to-point distance of 260 mm.

Conventional products were prepared by wrapping a paper making inorganic sheet in a paper tube (conventional product (1)), a diatomaceous earth molded product (conventional product (2)), and a ceramic fiber molded product (conventional product (3)). In addition, since the conventional product (1) and the conventional product (3) are made by a third party, the amount of the additive contained in the conventional product (1) and the conventional product (3) is not clear. As materials of the present invention, materials shown in A to E of Table 5 and additives were prepared.

The size of the sample to be tested is 31 mm in outer diameter, 18.5 mm in inner diameter (having a paper tube having an outer diameter of 25 mm and an inner diameter of 18.5 mm on the inner side). As for the ceramic fiber molded product, a product having an outer diameter of 39 mm and an inner diameter of 31 mm was used in which a paper tube having an outer diameter of 30 mm and an inner diameter of 17.6 mm was inserted.

As shown in Table 6, it can be seen that the bending strength of the product of the present invention is higher than the bending strength of the conventional products (1 to 3). More specifically, 100 wt% of wollastonite increases in strength as the amount of the additive increases, and the strength of the additive is 3 wt%, which is higher than that of the conventional product.

From the results shown in Table 6, it is possible to increase the strength of the heat-resistant protective pipe to be higher than that of the conventional product by setting the amount of additive to 3 wt% or more and 10 wt% or less in the case of 100 wt% wollastonite. It is also clear that the strength of the heat-resistant protective tube is increased as the amount of the additive is increased. Therefore, it is presumed that the strength of the heat-resistant protective tube can be made higher than that of the conventional product even when the amount of the additive exceeds 10% by weight.

In the present invention in which diatomite is added to wollastonite, when the amount of additive is 3% by weight and the amount of wollastonite is 80% by weight, the amount of additive is 5% by weight and the amount of wollastonite is 40% It can be seen that the same strength as that of the conventional product can be secured.

As shown in Table 6, the bending strength of the conventional product (3) is extremely low compared to the bending strengths of the conventional products (1, 2) It is thought that the presence of a gap between the two layers affects the effect. It can be said that the conventional product (3) has a problem in terms of strength in practical use.

As described above, the embodiments and the embodiments of the present invention have been described. However, it is also originally planned to properly combine the features of the embodiments and the embodiments.

It is also to be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in all respects. It is intended that the scope of the invention be indicated by the appended claims and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

INDUSTRIAL APPLICABILITY The present invention can be effectively applied to a heat-resistant protection pipe, a manufacturing method thereof, and an apparatus for manufacturing a heat-resistant protection pipe.

Claims (8)

Heat resistant inorganic powder containing at least 20% by weight of wollastonite or wollastonite at a ratio of 1.5% by weight or more and 15% by weight or less of an additive in solid content. The method according to claim 1, Wherein the additive comprises at least one of an organic dispersant, an organic binder and an inorganic binder. The method according to claim 1, Wherein the wollastonite is an acicular wollastonite. A step of producing a mixed material by mixing heat resistant inorganic powder containing at least 20% by weight of wollastonite or wollastonite with at least 1.5% by weight and at most 15% by weight of an additive in terms of solid content, A step of forming the tubular shaped body by molding the mixed material into a tubular shape, And a step of drying the tubular shaped body. 5. The method of claim 4, Wherein the tubular shaped body is produced by extrusion molding. 6. The method of claim 5, The heat-resistant protective pipe (1) is formed on the outer peripheral surface of the paper tube (2) The manufacturing process of the tubular molded body is characterized in that the paper tube 2 is moved in the axial direction while the mixed material is being extruded on the outer peripheral surface of the paper tube 2, The method comprising the steps of: Wherein the step of drying the tubular shaped body includes a step of drying the tubular shaped body on the outer peripheral surface of the paper tube (2). The method according to claim 6, Wherein a flow path of the mixed material is locally narrowed by providing a portion where the area of the flow path (18) is reduced in the flow path (18) of the mixed material. A heat-resistant protection tube (1) for forming a heat-resistant protection tube (1) on the outer surface of a paper tube (2) A cylinder 12 for mixing and supplying the materials therein, A space portion 15 connected to the front end of the cylinder 12 for receiving the paper tube 2 and a flow path for guiding the material supplied from the cylinder 12 onto the outer surface of the paper tube 2 And a molding die (14) having a plurality of projections (18) Wherein a neck portion (20) for locally reducing the area of the flow path (18) is provided in the flow path (18) of the material located in the forming die (14).

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